WO1997005507A1 - Detector - Google Patents

Abstract

A detector comprising object lenses (116 and 117) and photodetectors (PSD or PD) (118 and 119) for receiving the rays of light passing through the object lenses (116 and 117), wherein a plurality of fields of view are observed. The output signals from the photodetectors (118 and 119) are processed to detect changes in the quantity of light in a plurality of fields of view, or the displacement of the optical center of a field of view. This detection serves to find the appearance of objects that do not exist under the initial state.

Description

 Description Detecting device for objects

Technical field

The present invention relates to a device for detecting an object or the like, and particularly to a device for detecting an object or the like that optically detects the presence or absence of a person or an object ₍

Background art

 As an example of this type of conventional detection device, a reflection type photoelectric sensor will be described with reference to FIG. The conventional photoelectric sensor has a light-emitting element 1101 for projecting light toward an object to be detected and a light-receiving element 1102 for receiving the reflected light, and is obtained from an oscillation circuit 1103. The light emitting circuit 1104 is driven by the pulse signal, and the light emitting element 1101 is turned on. The light emitted from the light projecting element 111 hits the detection object, and the reflected light enters the light receiving element 110 2, where it is subjected to light-to-current conversion and amplified by the amplifier circuit 110 5. The amplified light receiving signal is compared with a preset threshold value by a comparator circuit 106, synchronized with the light emission pulse in a gate circuit 107, and integrated by a integrating circuit 1 for noise removal. After passing through 108, it is output from the output circuit 1109 to the outside of the sensor.

As a detection device with a relatively simple configuration, there is a passive type device. The passive detector is the detector itself. Or, as a device that works in conjunction with the detection device, it does not have an element that actively acts on the detection target (for example, a light source that shares a timing signal with the light receiving unit and illuminates in pulses). It uses energy from the target that is generated by an uncoupled artificial or natural energy source (eg, a lighting device or sunlight) acting on the target. As an example, a stationary human body detector using an integrating infrared detecting element (thermopile) as the detecting element will be described. Figure 2 shows the circuit diagram. When a person enters the detection area of the stationary human body detector, infrared rays emitted from the human body enter the thermopile 111 and an electromotive force corresponding to the amount of light is transmitted through the buffer 111 to the next stage. Sent to 13. The signal is amplified by the amplifier 11 13, the high-frequency noise is removed by the low-pass filter 11 14, and the signal is compared with the preset threshold value by the comparison circuit 11 15. When a signal exceeding the threshold value is input, the comparator circuit 110 outputs an ON signal. VR1 is a variable resistor for adjusting the offset voltage of the amplifier 111, VS is the power supply, and V is the offset voltage.

However, the conventional photoelectric sensor as shown in Fig. 1 emits light by itself and detects an object based on the amount of reflected light, so that the detection performance greatly depends on the amount of projected light. Since the amount of emitted light is determined by the current flowing through the light emitting element 111, it is difficult to reduce current consumption. On the other hand, when the sensor is driven by a battery, it is difficult to drive the sensor for a long time. Had a problem that it was difficult to reduce heat generation.

 In the detector shown in Fig. 2, since the output from the thermopile 1 1 1 1 1 appears as an integrated signal, the amplifier 1 1 1 3 must perform DC amplification, and the noise cut is Since it is necessary to perform only with a pass filter and cannot pass through a high pass filter, there is a problem that it is weak to low frequency noise.

 Also, since the output signal of the thermopile 111 is very small and equal to or less than the offset voltage V of the amplifier 111, when the DC is amplified by the amplifier 113, the offset voltage V Cannot be ignored. In order to eliminate the offset voltage V, a high-precision amplifier with a small off-voltage V is used for the amplifier 111 or an off-voltage adjustment circuit V R 1 as shown in Fig. 2 is required. However, the former has a problem that the price of the amplifier is high, and the latter has a problem that an adjustment process is required at the time of assembling, and the manufacturing cost is increased.

 Therefore, one of the objects of the present invention is to provide a device for detecting an object or the like having a low current consumption and a simple configuration.

 Another object of the present invention is to provide a detection device for an object or the like capable of removing high-frequency noise, offset noise of an amplifier, and other external noise.

Still another object of the present invention is to reduce the size, cost, and current consumption of the sensor, and to provide a highly accurate circuit. It is possible to provide a device for detecting objects, etc., which is not required.

 Still another object of the present invention is to provide a passive object detection device capable of securing a high S / N ratio and suppressing costs.

 Still another object of the present invention is to provide a passive-section-type object detection device capable of reducing the scale of a signal processing circuit.

 Still another object of the present invention is to provide an object detector which can surely detect an object to be detected, can reduce a light emission current, and can reduce current consumption. . Disclosure of the invention

 According to the present invention, there is provided a detection device for optically detecting the presence or absence of an object, comprising: an optical system; a photodetector configured to form a plurality of light receiving fields by a photodetector that receives light passing through the optical system; and a photodetector. Includes a light intensity fluctuation detector that detects the light intensity fluctuation between a plurality of light-receiving fields based on the output from

 The object detection device does not have a light projecting unit as in the related art, and detects an object based on a change in light amount from a plurality of light receiving fields. As a result, an object detection device having a simple configuration with low power consumption and current consumption can be provided.

Preferably, the optical system includes an optical fiber. Since an optical fiber is used, a plurality of light receiving fields corresponding to a plurality of light detecting elements can be set freely. According to another aspect of the present invention, a passive detection device that detects the presence or absence of an object or the like includes a detection element that detects a physical quantity, an amplifier that amplifies an output from the detection element, and a detection element that detects the output from the amplifier. It includes a determination unit that determines the state of the target in binary, and a switch that periodically interrupts the transmission of the output of the detection element to the amplifier. The output from the detection element is converted into a pulse signal by a switch and an amplifier, and the pulse signal is output as a more reliable binary signal by a determination unit according to the presence or absence of a detection target. The determination unit may change the output when the magnitude of the signal for each pulse pulsed by the switch and amplified by the amplifier continuously exceeds a predetermined value a predetermined number of times. . Also, the determining unit includes a first comparing unit that is pulsed by the switch and that pulses the signal amplified by the amplifier into a binary value based on a magnitude relationship with a predetermined reference value; An integration unit that integrates the output of the comparison unit and a second comparison unit that binarizes the output of the integration unit based on a magnitude relationship with a predetermined reference value and outputs the binary value. In addition, the detection device may include a filter that passes a signal in a band including the switching frequency of the switch.

The signal generated according to the physical quantity of the detection target by the detection element is switched into a pulse signal and amplified by an amplifier, and from the output of the amplifier, the state of the detection target is binarized by the judgment unit and output. . Since the signal size is binarized for each pulse, the pulse width is small and the wave height is large. The detector does not respond to impulsive noise. Therefore, a high SZN ratio can be secured. In addition, even if the signal obtained by the detection element is a very small signal, it is hardly affected by the offset voltage of the amplifier or low-frequency noise, so there is no need for an expensive high-precision amplifier or an offset adjustment step during manufacturing. become. As a result, costs can be reduced.

 In addition, by using a filter that passes signals in the band including the switching frequency of the switch, external low-frequency noise such as AC power can be cut off by high-frequency noise generated by signal processing circuits. As a result, a high SZN ratio can be secured and high sensitivity can be achieved.

 According to still another aspect of the present invention, a passive object detector for detecting an object to be detected by receiving light from the object to be detected comprises a plurality of light receiving fields, A plurality of light receiving elements receive light from an object to be detected or a background object present in the field of view, and a photodetector that outputs detection signals of a plurality of systems based on the received light amount. A gate that time-divisions each, a pulse generator that supplies a pulse signal to the gate so that each detection signal passes through this gate asynchronously and time-divisionally, A signal processor for detecting light amount fluctuations between the light-receiving fields by performing signal processing in one system by combining the divided detection signals.

Multiple detection signals output from the receiver are sent to the signal processor. By switching the input at a timing so as to be time-shared asynchronously by the gate, it is possible to process detection signals of a plurality of systems with a single signal processor. Unlike conventional photoelectric sensors, there is no need to provide signal processing circuits such as light receiving circuits and amplifier circuits, the number of which is equal to the number of light receiving outputs, and the size of the signal processing circuit can be reduced. The circuit section

□

 It is possible to reduce □ D, reduce current consumption, reduce the outer shape of the detector, reduce cost, and reduce the manufacturing defect rate. Also, by simplifying the circuit configuration, it is not necessary to match the characteristics of a plurality of circuits, so that high-precision components are not required.

 According to still another aspect of the present invention, a passive detector for detecting an object to be detected by receiving light from the object to be detected comprises: a plurality of light receiving fields; A light receiving device that receives light from a detected object or a background object within the device and outputs a light receiving signal based on the received light amount, and a determining unit that determines the presence or absence of the detected object based on the output of the light receiving device. And an auxiliary projector for projecting auxiliary light toward the inside of the light receiving field according to the output of the determination unit.

In passive detectors, when the ambient illuminance decreases or when an object to be detected enters the light-receiving field, a change in the amount of light received by the light-receiving device is detected by the determination unit, and an auxiliary light is emitted accordingly. The auxiliary light is used to detect the object to be detected, so that it is possible to detect the object reliably. Wear. Also, since there is no need to constantly emit light, it is possible to reduce the light emission current and reduce the current consumption. In addition, by reducing the current consumption, when the object detector is driven by the battery, the life of the battery can be extended. As a result, the number of battery replacements can be reduced, and installation in a place without power supply is possible.

 In still another aspect of the present invention, the object detection device includes:

A photodetector that outputs two light-receiving signals, a differential calculator that calculates the difference between the two light-receiving signals, and an object based on a comparison between the output of the differential calculator and two thresholds. A judgment unit for judging the presence or absence, an adjuster for adjusting the output of the differential arithmetic unit so that the output of the differential arithmetic unit becomes a predetermined value in an initial state, and a differential operation by the adjuster An adjustment amount detector that detects the amount of output adjustment, and a threshold setting device that sets two thresholds or a hysteresis width given to each threshold based on the output of the adjustment amount detector. including.

In the adjustment of the initial state, if there is no difference between the two received light signals when there is no sensing object (there is no contrast in the two received light fields), the noise components of the two received light signals are almost equal. And the noise component of the differential output becomes almost zero. Conversely, if there is a difference between the two light-receiving signals (contrast is present in multiple light-receiving fields), the noise component of the differential output will be the difference between the two light-receiving signals, that is, the magnitude of the signal component of the differential output It grows accordingly. Therefore, in the initial setting, the difference in the initial state The adjustment is performed by the adjuster so that the output of the dynamic operation unit becomes a predetermined value.The adjustment amount at that time is detected by the adjustment amount detector. Set the threshold or the hysteresis width of each threshold. By doing so, the threshold value or the hysteresis width can be appropriately set according to the amount of change in the differential output of the differential operator at the time of the initial setting. Then, the threshold is set above and below the detection signal, and when the level deviates from that level, a signal indicating that the object has been detected is output, so that the object can be detected regardless of the output change direction. As a result, it is possible to provide a high-sensitivity passive detection device that can perform appropriate sensitivity adjustment independent of the use environment and the like. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a diagram showing the configuration of a conventional reflective photoelectric sensor. FIG. 2 is a configuration diagram showing an example of a conventional detection device.

 FIG. 3 is a block diagram showing the basic principle of the object detection device according to the first embodiment.

 FIG. 4A is a diagram showing a configuration of a light receiving unit of the detection device according to one embodiment of the present invention, and FIG.

 FIGS. 5A to 5D are a diagram showing a configuration of a light receiving unit according to Example 1a and a light intensity distribution diagram on a PSD.

FIG. 6 is a block diagram of the signal processing unit according to the embodiment 1a. 7A to 7D are a configuration diagram of a light receiving unit, a light intensity distribution diagram on a PSD, and a block configuration diagram of a signal processing unit according to Example 1b.

 FIG. 8 is a block diagram of the light receiving unit and the signal processing unit according to the embodiment 1c.

 FIG. 9 is a block diagram of a signal processing unit according to a modification of the embodiment 1c.

 FIG. 10 is a block diagram of a light receiving unit and a signal processing unit according to Embodiment 1d.

 FIG. 11a is a block diagram of the light receiving unit and the signal processing unit according to the embodiment 1e.

 FIG. 11b is a block diagram of a modification of the embodiment 1e. FIG. 12 is a block diagram when a division circuit is used for the signal processing of the embodiment 1e.

 FIG. 13 is a diagram illustrating a configuration of a detection device according to a modified example of Example 1f.

 FIG. 14 is a configuration diagram of an apparatus according to Example 1g.

 FIG. 15 is a configuration diagram showing a modification of the embodiment 1g.

 FIG. 16 is a configuration diagram of an apparatus according to Example 1h.

 Figure 17 shows the spectral distribution of various light sources.

 FIG. 18 is a view showing a modification of the embodiment 1h.

 FIG. 19a is a diagram showing the configuration of the device according to Example 1i, and FIG. 19b is a circuit diagram thereof.

FIG. 20a is a diagram showing the configuration of the device according to the embodiment 1j, FIG. 20b is the circuit diagram.

 FIG. 21a is a diagram showing the configuration of the device according to Example 1k, and FIG. 21b is a circuit diagram thereof.

 FIG. 22A is a diagram showing the configuration of the device according to Example 1m, and FIG. 22B is a circuit diagram thereof.

 FIG. 23A is a diagram showing the configuration of the device according to Example 1n, and FIG. 23B is a circuit diagram thereof.

 FIG. 24 is a diagram illustrating a detection device according to Example 1o.

 FIGS. 25a to 25i are time charts of the operation of the embodiment 1o.

 FIG. 26 is a circuit diagram showing a specific example of a judgment unit including a comparison circuit, an integration circuit, and an output circuit.

 Figure 27a to Figure 27d are time charts for the above operation.o

 FIG. 28 is a circuit diagram showing another example of the determining unit.

 Figures 29a to 29e are time charts of the above operation.

 FIG. 30 is a circuit diagram showing still another example of the judgment unit.

 FIGS. 31a to 311 are time charts of the above operation.

 FIG. 32 is a diagram illustrating a basic configuration of a passive-type detection device according to the second embodiment.

 FIG. 33 is a configuration diagram of a photodetector according to Embodiment 2a.

Figures 34a to 34h are time charts of Example 1a. O

 FIG. 35a is a diagram showing a configuration example of a cycle Z duty ratio variable circuit for generating a switching signal SG, and FIG. 35b is a timing chart thereof.

 Fig. 36 is a diagram showing the configuration of the detection device according to the embodiment 2b.

 FIG. 37 is a diagram showing the relationship between the circuit components and the parallel capacitance C i of the capacitor in Example 2b.

 FIG. 38 is a circuit diagram showing a specific example of the above-described comparison circuit and a determination unit including a determination unit.

 Fig. 39a to Fig. 39 d are the timing charts for the above operation.

Q O

 FIG. 40 is a circuit diagram showing another example of the determining unit.

 Figure 41a to Figure 41e are time charts for the above operation.

 FIG. 42 is a circuit diagram showing still another example of the judgment unit. FIGS. 43a to 431 are time charts of the above operation.

 FIG. 44 is a diagram showing the configuration of the infrared detector according to the embodiment 2c.

 FIG. 45 is a diagram illustrating a configuration of a detection unit of a temperature detector according to Embodiment 2d.

FIGS. 46a to 46d are a plan view and a cross-sectional view, an equivalent circuit diagram, and signals showing a configuration of the pressure detector according to the embodiment 2e. FIG. 3 is a diagram illustrating a configuration of a processing unit.

 Figures 47a to 47h are time charts of Example 2c.

O

 FIG. 48 is a diagram illustrating the configuration of the detection unit of the temperature sensor according to Embodiment 2f.

 FIG. 49 shows a configuration according to Example 2g.

 FIG. 50 is a diagram showing a configuration according to Example 2h.

 FIG. 51 is a configuration diagram of a detector according to Embodiment 3a.

 FIGS. 52a to 52i are time charts of the detection operation of the detector according to the embodiment 3a.

 FIG. 53 is a configuration diagram of a detector according to Embodiment 3b.

 FIG. 54 is a diagram showing a configuration near the switch of the detector according to the embodiment 3c.

 FIG. 55 is a diagram showing a configuration near the switch of the detector according to Embodiment 3b.

 FIG. 56 is a configuration diagram of a detector according to Embodiment 3e.

 FIGS. 57a to 57m are time charts of the detection operation of the detector according to Example 3e.

 FIG. 58 is a configuration diagram of a detector according to Embodiment 3f.

 Figs. 59a to 59i are time charts of the detection operation of the detector according to the embodiment 3f.

 FIG. 60 is a configuration diagram of a detector according to Embodiment 3g.

FIGS. 61a to 61j are time charts of the detection operation of the detector according to the third embodiment. Figures 62a to 62j are time charts of the detection operation of the detector according to Example 3h.

 FIG. 63 is a configuration diagram of a detector according to Embodiment 3i.

 FIGS. 64a to 64j are time charts of the detection operation of the detector according to Embodiment 3j.

 FIG. 65 is a configuration diagram of a detector according to Embodiment 3j.

 FIGS. 66a to 66j are configuration diagrams of the detector according to the embodiment 3j.

 FIG. 67 is a configuration diagram of a detector according to Embodiment 3k.

 Fig. 68a to Fig. 68j are time charts of the detector field detection operation according to embodiment 3k.

 FIG. 69 is a configuration diagram of a detector according to Embodiment 31.

 FIG. 70 is a configuration diagram of a detector according to Embodiment 3m.

 FIG. 71 is a configuration diagram of an infrared sensor according to Embodiment 3n. FIG. 72 is a configuration diagram of the temperature sensor according to the third embodiment. FIG. 73A is a plan view and a sectional view of a pressure sensor according to Example 3p, and FIG. 73B is a circuit diagram of the sensor.

 FIG. 74 is a configuration diagram of a gas sensor according to Embodiment 3q. FIG. 75 is a block diagram showing a basic configuration of the detector according to the fourth embodiment.

 FIGS. 76a to 76e are diagrams showing the distribution of the amount of received light on the photodetector.

FIG. 77 is a block diagram showing the internal configuration of the comparison circuit and the discrimination circuit. FIGS. 78a to 78p are time charts of the output of the differential amplifier and the operation of the comparison circuit and the discrimination circuit.

 Fig. 79 is a block diagram showing the configuration of the detector in the case where the number of reflecting surfaces is greater than the number of receiving and emitting light.

 FIG. 80 is a diagram showing a change in the amount of received light with respect to the position of the detection object.

 Fig. 81 is a block diagram showing a detection circuit that uses a battery as the power supply and supplies power intermittently.

 Figure 82 is a block diagram of the detector when power is supplied to the storage battery by the solar cell.

 Fig. 83 is a block diagram showing the configuration of a detector that supplies power to a storage battery by hydroelectric power generation.

 Figure 84 is a schematic diagram showing a method for adjusting the position of the detector.

 FIG. 85 is a diagram showing the configuration of a light receiving section having a built-in LED for position adjustment.

 FIG. 86a shows a reflector, and FIG. 86b shows a configuration of a four-divided PD.

 Fig. 87 shows the optical system with an aperture between the photodetector and the lens.

 Fig. 88 is a diagram showing the arrangement of detectors in the parking lot system.

Figure 89 is a block diagram showing the configuration of the parking lot system. Figure 90 is a block diagram showing the configuration of the vehicle detection system on the road surface. FIG.

 Figure 91 is a block diagram showing the configuration of the system for measuring the number of axles.

 Figure 92 is a block diagram showing the configuration of the passgate system.

 Figure 93 shows the arrangement of detectors in the passgate ο

 Figure 94 is a block diagram showing the configuration of the number-of-entrants management system.

 FIG. 95 is a block diagram showing the configuration of the positioning device. Figure 96 shows the analog output of the detector.

 FIG. 97 is a schematic diagram showing the configuration of the length measuring device.

 Figure 98 is a block diagram showing the configuration of the monitoring system. FIG. 99 is a schematic diagram showing the configuration in the fifth embodiment. FIG. 100 is a diagram showing an area sensor using the detector according to the fifth embodiment.

 FIG. 101 is a diagram showing a specific usage example of the area sensor. FIGS. 102 to 104 are diagrams illustrating examples of use of an area sensor using a detector according to the fifth embodiment.

 FIG. 105 is a configuration diagram of a detector according to Embodiment 6a.

 FIGS. 106a to 1061 are timing charts of the detection operation of the detector according to the embodiment 6a.

Fig. 107a shows the auxiliary light emitting part of the detector according to Example 6a, and Fig. 107b shows the detector of Example 6a. It is a circuit diagram and a logic diagram of a light emission trigger circuit.

 FIG. 108 is a configuration diagram of a detector according to Embodiment 6b. FIG. 109 is a configuration diagram of a detector according to Embodiment 6c. FIGS. 110a to 110n are time charts of the detection operation of the detector according to the embodiment 6c.

 FIG. 11a is a time chart of the detection operation of the detector according to Example 6c, and FIG. 11b is a diagram showing the characteristics of the detection operation.

 FIG. 112 is a block diagram showing a configuration of a detector according to Example 6d.

 Figures 1 1 3 3 to 1 1 3 e are given by the time chart of the detection operation.

 FIG. 114 is a diagram showing the configuration of the output inhibition circuit.

 FIG. 115 is a configuration diagram of a detector according to Example 6e.

 FIG. 116 is a configuration diagram of a detector according to Example 6f.

 FIG. 117 is a diagram showing a configuration of a detector according to Example 6g.

 Fig. 118 is a circuit diagram of a detection circuit equipped with both output prohibition circuits, that is, output prohibition at power reset and output prohibition at voltage drop.

 Figure 1 19 shows the time chart of the detection operation.

 FIGS. 12 and 0 are circuit diagrams of the warning display circuit of the detector according to Example 6h.

FIG. 121 is a configuration diagram of a comparison unit, a calculation unit, and a determination unit of the detector according to the embodiment 6i, and FIG. 122 is a circuit diagram of an output inhibition circuit. FIG. 123 is a block diagram showing the configuration of the detector according to Embodiment 6j.

 FIGS. 124a to 124d are timing charts of the detection operation.

 FIG. 125 is a block diagram of a detection device according to Example Ίa.

 FIGS. 126a to 126i are time charts of the operation according to the embodiment 7a.

 FIG. 127 illustrates the basic concept of the initial setting. Fig. 128a and Fig. 128b are a circuit diagram when the reference voltage of the operation calculator is changed and a diagram showing the relationship between the reference voltage and the two threshold values at that time. c and FIG. 128 d are a circuit diagram when the amplification factor of the amplifier circuit is changed and a diagram showing the relationship between the reference voltage and the two thresholds at that time.

 Fig. 12a and Fig. 12b are a circuit diagram in the case of attenuation of the received light signal and a diagram showing the relationship between the reference signal and the two thresholds at that time. Fig. 1229d is a circuit diagram in the case of changing the DC offset value of the amplification circuit output and a diagram showing the relationship between the reference voltage and the two thresholds at that time.

 FIG. 130 is a block diagram of a detection device according to Example 7b.

FIG. 13 1 is a specific circuit diagram for the initial setting in the embodiment 7a. Fig. 13 2 is a main circuit diagram when only the hysteresis width is changed at the time of initial setting.

 Fig. 13 3 is a main circuit diagram when only the threshold is changed at the time of initial setting.

 FIG. 13A is a partial circuit diagram showing a modification of the change amount detection unit at the time of initial setting, and FIG. 13B is a time chart for explaining its operation.

 Fig. 135 is a main part circuit diagram when the threshold value is changed at the time of initial setting.

 FIG. 136 is a circuit diagram of a light receiving section of a detection device according to Embodiment 7c of the present invention.

 FIGS. 137a to 137g are time charts for explaining the operation. BEST MODE FOR CARRYING OUT THE INVENTION

 (1) First embodiment

First, the basic principle of the device for detecting an object or the like according to the present invention will be described. Referring to FIG. 3, detection device 100 does not have a light projecting unit, but includes a light receiving unit and its signal processing unit. The plurality of light receiving elements 101, 102 receive light from the detected object in the plurality of light receiving fields, and the signal processing unit receives signals from the light receiving elements 101, 102. Amplification circuits 103, 104 and 105, 106, Differential amplification circuits 107, 108, and 109, Comparison circuit 110, Oscillator circuit 111, Integrator circuit 1 1 2, output The circuit is composed of 1 1 and 3. The output circuit 113 converts the output of the integration circuit 112 into a binary value based on a magnitude relationship with a predetermined reference value. Fig. 4a shows the configuration of the light receiving sections 101 and 102. The light-receiving elements 101, 102 are composed of lenses 116, 117, which form a plurality of light-receiving fields, and a position-sensing device (position detecting element: hereinafter, referred to as PSD). , 1 19. Figures 4b and 4c show the light intensity distribution on the PSD with and without the detected object. As shown in the figure, by detecting the movement of the center of gravity G on the PSD 118 or PSD 119 due to the change of the image in the light receiving field or the fluctuation of the light quantity between the multiple light receiving fields, the background 1 can be detected. Before 4, the presence or absence of the detected object 15 that did not exist in the initial state is detected.

 Hereinafter, specific examples applying the above principle will be described.

 (l a) Example 1a

 5a to 5d show the light receiving portion and P according to Embodiment 1a of the present invention.

4 shows a light intensity distribution on SD. The receiving field of view a is constituted by the lens 1 16 and the PSD 1 18, and the receiving field b is constituted by the lens 1 17 and the PSD 1 19. These fields are illuminated by natural scattered light (illumination light, sunlight, etc.) from the surroundings. When no object is detected, the background images illuminated by natural scattered light are reflected on the PSDs 118 and 119 through the lenses 116 and 117, respectively. When there is no contrast in the background, the light intensity distribution on the PSD is uniform, as shown in Fig. 5b. Become a heart. If there is contrast in the background, the initial setting is performed so that the position of the center of gravity G becomes the center of the PSD.

 Here, when a detection object 15 having a high reflectance equal to or higher than the background is within the light receiving field, the reflected light from the detection object 15 is larger than the reflected light from the background 14. As shown in FIG. 5c, on the PSD, the light intensity P at the portion where the image of the detection object 15 is reflected is large, and the light intensity P at the portion where the background 14 is reflected is small. Therefore, the position of the center of gravity G moves toward the image on the detection object 15 side. The movement amount is ALa in PSD118, and ALB in PSD119.

 Also, when a detection object 15 having a low reflectance equal to or lower than that of the background 14 is within the light receiving field, the reflected light from the detection object 15 is smaller than the reflected light from the background 14. As shown in 5b, on the PSD, the light intensity P of the portion where the image of the detection object 15 is reflected is small, and the light intensity P of the portion where the background is reflected is large. Therefore, the position G of the center of gravity moves toward the image on the background side.

 FIG. 6 shows a block configuration of the signal processing unit according to the embodiment 1a.

Each PSD outputs a photocurrent corresponding to the light input power to the PSD and the position of the optical center of gravity. The currents I 1 and I 2 are output from PSD 118, and the currents I 3 and I 4 are output from PSD 119. Is output. Each of these photocurrents is converted to a voltage by the I conversion circuit. The current I 1 is set to the voltage V 1 by the I / V conversion circuit 1 2 1, and the current I 2 is set to 1 V conversion circuit 1 2 2 to voltage V 2, current I 3 to I V conversion circuit 1 2 3 to voltage V 3, current I 4 to I conversion circuit 1

At 24, they are converted to voltages V4, respectively. The voltages V 1 and V 2 are subtracted by the differential amplifier circuit 107 to obtain (V 1—V 2), and the voltages V 3 and V 4 are subtracted by the differential amplifier circuit 108 to obtain (V

3-V). These are further subtracted by the differential amplifier circuit 109, and the output is

 (Output) = (V 1-V 2) one (V 3-V 4)

Becomes This result is compared with a preset threshold value by a comparator circuit 110, passes through an integration circuit 112 for noise removal, and is output from an output circuit 113.

 As described above, the detection device for the object and the like in Example 1a does not emit light by itself, operates using natural scattered light as a light source, and receives an object that did not exist in the initial state into the light reception field. Since the position of the optical center of gravity on the element fluctuates and the amount of the fluctuation is detected to detect the presence or absence of an object, current consumption can be easily reduced. However, if there is a change in either the light-receiving field a or the light-receiving field b shown in Fig. 5a, an output can be obtained, so that the light-receiving field can be widened compared to the case with one receiver, and Since the amount of movement of each PSD is added at the overlapping part of, the sensitivity is doubled.

 (l b) Example b

FIGS. 7A to 7D show block diagrams of a light receiving unit, a light intensity distribution on a PSD, and a signal processing unit according to the embodiment 1b. This implementation In the example, a light receiving field is constituted by one lens 116 and a PSD 118. This field is illuminated by natural scattered light (illumination light, sunlight, etc.) from the surroundings. In the absence of an object, PSD 118 reflects the background image illuminated by natural scattered light through lens 16. If there is no contrast in the background 14, the light intensity distribution on the PSD is uniform as shown in Fig. 7b, and the light center of gravity G of the PSD becomes the center of the PSD. If the background 14 has contrast, the initial settings are made so that the center of gravity G is the center of the PSD.

 The PSD 118 outputs a photocurrent according to the light input power to the PSD 118 and the position of the optical center of gravity, and the PSD 118 outputs the photocurrents I 1 and I 2. These photocurrents are converted to voltages by the IZV converters 1 2 1 and 1 2 2. Converted to V2. The voltages V 1 and V 2 are subtracted by the differential amplifier circuit 107 to obtain (VI−V 2). This result is compared with a preset threshold value by a comparator circuit 110, passes through an integration circuit 112 for noise removal, and is output from an output circuit 113.

If the detected object 15 having a contrast different from that of the background 14 is in the light receiving field, the image is reflected on the PSD, the position of the center of gravity G moves, and the Each output photocurrent is different from the initial state where the background image is shown. Here, P when there is no detected object 15 (the background is detected) If the output current of SD18 is I11, 121, the voltage after IZV conversion is VII, V21, and the voltage after differential amplification is (VII-V21). If the output current of PSD 18 with sensing object 15 is I12 and 122, the voltage after IV conversion is V12 and V22, and the voltage after differential amplification is (V12-V22). Here, the threshold value of the comparator circuit 10 is set above and below the output value (VII-V21) of the differential amplifier circuit 107 when there is no detection object 15. Signals that cross this threshold value are set. For example, when (V12-V22) is input, an ON signal is output from the comparison circuit 110, and the signal passes through the integration circuit 112 for noise removal and then from the output circuit 113. An intrusion signal of the detected object is output.

 Thus, the detection device of Example 1b does not emit light by itself, operates using natural scattered light as a light source, and when an object that was not present in the initial state enters the light receiving field, the light weight on the light receiving element Since the position of the heart fluctuates and the difference of the photocurrent according to the fluctuation amount is detected to detect the presence or absence of an object, current consumption can be easily reduced. This is advantageous in terms of size and cost as compared with those having a plurality of light receivers.

 (1c) Example 1c

FIG. 8 shows a block configuration of the light receiving unit and the signal processing unit according to the embodiment 1c. The receiving field of view 1 is composed of the lens 1 16 and the PD 1 of the two-part photodiode (PD) 1 3 1, and the receiving field 2 is composed of the lens 1 16 and the PD 2 of the two-part 13 1 Lens 1 1 7 and split by PD 3 of PD 1 3 2 An optical field of view 3 is constituted, and a light receiving field of view 4 is constituted by the lens 1 17 and the PD 4 of the two divided PDs 13 2. These fields are illuminated by natural scattered light (illumination light, sunlight, etc.) from the surroundings. Each PD outputs a photocurrent according to the light input power to the PD, PD 1 outputs I 1, PD 2 outputs I 2, PD 3 outputs I 3, and PD 4 outputs I 4 . These photocurrents are converted into voltages by the IZV conversion circuits 1 2 1 to 1 2 4, and the current I 1 is V 1 by the I conversion circuit 1 2 1, and the current I 2 is V 2 by the I / V conversion circuit 1 2 2 The current I 3 is converted to V 3 by the IZV conversion circuit 123 and the current I 4 is converted to V 4 by the IV conversion circuit 124. The voltages V 1 and V 2 are subtracted by the differential amplifier circuit 107 to obtain (V 1 − V 2), and the voltages V 3 and V 4 are subtracted by the differential amplifier circuit 108 to obtain (V 3− V 4). These are further subtracted by the differential amplifier circuit 109, and the output is

 (Output) = (V 1 — V 2) — (V 3 — V 4)

Becomes This result is compared with a preset threshold value by a comparator circuit 110, passes through an integrating circuit 112 for noise removal, and is output from an output circuit 113.

When there is no object to be detected, the background image illuminated by the naturally scattered light is reflected through the lens on the two-divided PDs 13 1 and 13 2. If there is no contrast in the background, the amount of light incident on PD 1 and PD 2 and the amount of light incident on PD 3 and PD 4 are equal, and the output of the differential amplifier circuit 109 becomes zero. If there is contrast in the background, the amount of light incident on PD 1 and PD 2 and PD 3 Since the amount of light incident on PD 4 is different and the output of the differential amplifier circuit 109 does not become 0, the initial setting is made so that this becomes 0.

 Now, if a detection object 15 with a reflectance equal to or higher than that of the background is in the light receiving fields 1 and 4, the reflected light from the detection object 15 will be larger than the light reflected from the background. Then, the light intensity P in the portion where the image of the detection object 15 is reflected is large, and the light intensity P in the portion where the background is reflected is small. Therefore,

 (V1-V2)> 0, (V3-V4) <0, and the output of the differential amplifier circuit 109 becomes 0 or more, which is different from the initial state. Intrusion can be detected.

 In addition, when a detection object 15 having a low reflectance equal to or less than that of the background is within the light receiving fields 1 and 4, the reflected light from the detection object 15 is smaller than the light reflected from the background. Above, the light intensity P in the part where the image of the detected object is reflected is small, and the light intensity P in the part where the background is reflected is large. Therefore,

 (V1-V2) <0, (V3-V4)> 0, and the output of the differential amplifier circuit 109 becomes 0 or less, which is different from the initial state. Intrusion can be detected. ,

As described above, the detection device of Example 1c does not emit light by itself, and operates using naturally scattered light as a light source. The balance of the light amount is lost, and the fluctuation amount is detected to detect the presence or absence of the detected object, so that current consumption can be easily reduced. According to the present embodiment, an output can be obtained if there is a change in any of the light-receiving fields 1, 2, 3, 4, and so on. The object can be detected, and in the overlapping part of the field of view, the amount of change in the amount of light of each PD is added, so the sensitivity is doubled.

 FIG. 9 shows a block configuration of a signal processing unit according to a modification of the embodiment 1c.

 In the figure, only the configuration after the output of the above-mentioned IV conversion circuits 12 1 to 12 4 is shown. The voltages V 1 and V 2 are subtracted by the differential amplifier circuit 107 to obtain (VI−V 2) and added by the adder 107 ′ to obtain (V 1 + V 2). V 3 and V 4 are subtracted by the differential amplifier circuit 108 to obtain (V 3 — V 4), and are added by the adder 108 ′ to obtain (V 3 + V 4). Furthermore, each of the differences is divided by the sum in the divider circuits 1 3 5 and 1 3 6 to obtain (V 1 -V 2) / (V 1 + V 2), (V 3 -V 4) / (V 3 + V 4), and is subtracted by the differential amplifier circuit 13 7 to obtain (VI-V 2) / (V 1 + V 2)-(V 3-V 4) / (V 3 + V 4). Since the output ratio is handled by using such a division process, the object can be accurately detected even when the entire field of view becomes bright or dark.

(Id) Example 1 d FIG. 10 shows a block diagram of a light receiving unit and a signal processing unit according to the embodiment 1d. In the present embodiment, a two-divided PD 140 is used as a light receiving element, and the divided PDs are designated as PDa and PDb. The light receiving field of view a is constituted by PD a and the lens 1 16, and the light receiving field b is constituted by PD b and the lens 1 16. These fields are illuminated by natural scattered light (illumination light, solar light) from the surroundings. When no object is detected, the background image illuminated by natural scattered light is reflected on the PD a and b through the lens 16. If there is no contrast in the background, the light intensity distribution on the PD is uniform, and the photocurrents output from PD a and b are equal. If there is contrast in the background, the photocurrents output from PD a and b are different.

Now, if a detection object 15 having a contrast different from the background is within the light receiving field, the image is reflected on PD 10 and the photocurrent output from PD a and b is reflected in the background image. Is different from the initial state. When there is no sensing object 1 5 (background), the output of PD a is I al, the output of PD b is I bl, the output of PD a with sensing object is I a2, and the output of PD b is I b2 You. As shown in FIG. 10, the photocurrent output of PD a is converted to a voltage Va by an I / Ί converter circuit 121, and the photoelectric output power of PD b is converted to a voltage by an I / V converter circuit 122. Converted to V b. If there is no object 15, Val and Vbl are obtained. If there is 15 object, Va2 and Vb2 are obtained. These are subtracted by the differential amplifier circuit 109, and if there is no sensing object 15 (V al-Vbl), and if there is a detected object 15 (Va2-Vb2).

 The threshold value of the comparator circuit 110 is set above and below the output value (Val-Vbl) of the differential amplifier circuit 109 when there is no sensing object 15. Signals that cross this threshold, for example (Va2 — When Vb2) is input, an ON signal is output from the comparator circuit 110, and the signal passes through the noise removal integration circuit 112, and then enters the detection object 15 from the output circuit 113. Is output.

 As described above, the detection device of Example 1d does not emit light by itself, operates using natural scattered light as a light source, and when an object that did not exist in the initial state enters the light receiving field, the light detecting field Since the amount of light fluctuates and the amount of fluctuation is detected to detect the presence or absence of an object, current consumption can be easily reduced. This is advantageous in terms of size and cost as compared with those having a plurality of light receivers.

 (1 e) Example 1 e

 FIG. 11a shows a block configuration of the light receiving unit and the signal processing unit according to the embodiment 1e. In this embodiment, two PDs 14 1 and 14 2 are used as light receiving elements. The light receiving field of view a is constituted by the PD 141 and the lens 1 16, and the light receiving field b is constituted by the PD 142 and the lens 117. These fields of view are separated from each other, and both fields are irradiated with natural scattered light (illumination light, solar light) from the surroundings.

When no object is detected, the background image illuminated by natural scattered light is output to the PDs 14 1 and 14 2 through the lenses 1 16 and 1 17. It is reflected. When there is no contrast in the background, the light intensity distribution on the PD is uniform, and the photocurrents output from the PDs 141 and 142 are equal. If there is contrast in the background, the photocurrent output from PDs 14 1 and 14 2 will be different.

 Now, the detection object 1

Consider the case where 5 enters. At this time, the image is projected on the PD 142, and the photocurrent output from the PD 142 is different from the initial state where the background image is projected. If there is no sensing object 15, the output current of PD 14 1 in the background is Ial, the output current of PD 14 2 is I bl, and the output of PD 14 1 when sensing object 15 is in the light-receiving field b. The current remains at Ial, and the output current of PD142 becomes Ib2. As shown in Fig. 11a, the photocurrent output of PD 14 1 is converted to voltage Va by the I / V converter 121, and the photocurrent output of PD 14 2 is converted by the IV converter 12 2. Since it is converted to voltage Vb, Val and Vbl are obtained when there is no sensing object 15, and Val (no change) and Vb2 are obtained when there is a sensing object. These are subtracted by the differential amplifier circuit 109 to obtain (Val-Vbl) when there is no detected object 15 and (Val-Vb2) when there is a detected object.

The threshold value of the comparator circuit 110 is set above and below the output value (Val—Vbl) of the differential amplifier circuit 109 when no object is detected, and a signal that crosses the threshold value, for example, (Val— When Vb2) is input, an ON signal is output from the comparator circuit 110, and the signal passes through the integration circuit 112 for noise elimination. The intrusion signal of the detection object 15 is output from the circuit 1 13.

 Thus, the detection device of Example 1e does not emit light by itself, operates using natural scattered light as a light source, and when an object that did not exist in the initial state enters the light-receiving field, the light-receiving field Since the amount of light fluctuates and the amount of fluctuation is detected to detect the presence or absence of an object, current consumption can be easily reduced. Also, in this case, since the light receiving fields are separated from each other, there is an advantage that the light receiving field can be widened and a larger object can be detected.

 Next, a modified example of the embodiment 1e will be described with reference to FIG. 11B. Referring to FIG. 11b, in a modified example, optical fibers 151, 152 are provided instead of lenses 116, 117. The other parts are the same as in FIG.

 Since an optical fiber is used instead of a lens, the light-receiving field can be set freely.

 (If) Example 1

 FIG. 12 is a block diagram in the case where a division circuit is used for the signal processing of the embodiment 1e and a power supply circuit is added. If a division circuit 144 is used in place of the differential amplifier circuit and the ratio between the voltages Va and Vb is calculated, the output will be V bl ZV al if there is no sensing object, and if there is an sensing object, Since V b2 ZV al, this ratio does not change even if the entire field of view becomes brighter or darker at the same ratio, and is more resistant to changes in natural scattered light.

In the example shown in Fig. 12 above, battery 145 is used as the power source. This eliminates the need for electrical work and allows installation of the detector in places where there is no commercial power supply, eliminating the restrictions on installation locations.

 In the example of Fig. 12 above, the detection device 51 is an I / V conversion circuit 121, 122, a division circuit 144, a comparison circuit 110, an integration circuit 112, and an output circuit 111. 3 and the like, and the power supply thereto is performed by a power supply circuit 146 which is intermittently supplied by the clock of the oscillation circuit 111. As a result, the current consumption can be further reduced.

 FIG. 13 shows another configuration of the detection device 51 shown in FIG. A solar battery 52 is used as a power supply for the detector 51 having the above-described configuration, and the power is supplied to a battery 53 including a large-capacity capacitor or a secondary battery. As a result, electrical work is not required, and there is no restriction on the installation location of the detector 51 o

 (1 g) Example 1 g

FIG. 14 shows the configuration of the device according to Example 1g. The present embodiment is a detection device that detects a person's hand or the like that has entered the wash basin 55 with the detector (sensing unit) 51 and absorbs water into the faucet 56. A detector (sensing part) 51 is installed near the wash basin 55. When a hand or the like is detected by the detector 51, a solenoid valve (valve) 5 7 disposed on the water passage is provided. A valve open signal for is input to the control unit (valve drive circuit) 58, and the output drives the solenoid valve 57 to open. Opening of this solenoid valve 5 7 Perform more spouting. When the hand comes off the detection area of the detector 51, a valve close signal is output from the detector 51, and the control unit 58 closes the solenoid valve 57 to stop water.

 In addition, a hydraulic generator 59 with an impeller is arranged on the water channel, and the power generated by the generator 59 is charged into the storage battery 60, and the output is used as the power source for the detector 51. . When the valve is open, the impeller is rotated by water force, and the generator 59 outputs a current with a frequency corresponding to the rotation speed.This output current is full-wave rectified by the rectifier circuit 61 and the charging circuit 6 2. It is supplied to the storage battery 60 via the diode 63, and is charged. The detector 51 is operated by the charged power. According to this configuration, since there is no need to supply power from the outside, there is an effect that it is not necessary to install the detector 51 in a non-power supply place or to perform electrical work.

 As shown in FIG. 15, the detector 51 of the present embodiment

5. Also applicable to human body detection for automatic water washing.

 (1 h) Example 1 h

FIG. 16 shows the configuration of the device according to Example 1h. When the light receiving element 67 of the detector 51 directly receives sunlight, the light output of the light receiving element 67 is saturated by the strong light, and the light output of the light receiving element 67 changes with respect to the change of the optical signal due to the intrusion of the object into the light receiving field. Loses sensitivity. Therefore, the illuminator 68 in the space is used as the light source of the detector 51, and of the light emitted by the illuminator 68, only light in a predetermined wavelength range including a wavelength range having a large light amount is transmitted. Optical filter Arrange 69 in front of the light receiving element 67 to cut out light (mainly sunlight) other than illumination light as much as possible. Figure 17 shows the spectral distribution of various light sources. As can be seen from the figure, for example, when an incandescent lamp is used as the light source, an optical filter that cuts light of 700 nm or less is used, and when a fluorescent lamp is used as the light source, 550 to 65 Use an optical filter that cuts light other than 0 nm light. Further, as shown in FIG. 18, a configuration in which an optical filter 69 is arranged on the front of the lenses 116 and 117 is also conceivable. In this case, the optical filter 69 may have a detachable structure so that the optical filter 69 can be attached later according to the wavelength of the illumination light in the space of the detector 51.

 (1i) Example 1 i

 FIGS. 19a and 19b show the configuration and circuit of the device according to Example 1i. The detector 51 of the present embodiment is installed around a display device 70 such as a television or a guidance display, and monitors the visual field in front of the display device 70 with the detector 51. When a person enters the field of view, that is, when the presence of a person is detected, the detector 51 outputs a signal to turn on the power switch 71 of the display device 70, and when the person goes out of the field of view, Outputs a signal to turn off the power switch 71. Thereby, the power of the display device 70 is automatically turned on / off.

 (1 j) Example 1 j

FIGS. 20a and 20b show the configuration and circuit of the device according to Example 1j. The detector 51 of this embodiment is used for It is installed around each device 73 (hereinafter referred to as a pachinko machine) such as an ATM, a vending machine, and a vending machine, and monitors the field of view in front of it. Detection signals from the ball detection unit 74 and the detector 51 of each pachinko machine 73 are transmitted to the control unit 75. When the detector 51 does not detect a person in the field of view, the control unit 75 controls so that the ball is not ejected from the ball ejection unit 76. In the case of vending machines and vending machines, control is performed so that transactions are not performed unless a person is detected in the field of view of the detector. This functions as a security system.

 (l k) Example 1 k

 FIGS. 21a and 21b show the configuration and circuit of the device according to Example 1k. The detector 51 of the present embodiment is installed so as to be in front of a desk 78, and when a person enters the field of view, the switch 71 of the illuminator 79 is automatically turned on, and The switch 71 of the illuminator 79 is automatically turned off when it comes off. This can save energy.

 (1 m) Example 1 m

Figures 22a and 22b show the configuration and circuit of the device of Example 1m. The detector 51 of this embodiment is installed around the door 80 in a room or toilet, and when a person enters the field of view, the switch 71 of the ventilation fan 81 is automatically turned on, and When it goes out of the field of view, the switch 71 of the ventilation fan 81 is automatically turned off. As a result, energy can be saved as described above. Also, In addition to the ventilation fan, it can be applied to air conditioners such as air conditioners to control so that the wind does not blow in the direction where people are directly.

 (I n) Example 1 n

 FIGS. 23a and 23b show the configuration of the device and the circuit block according to Embodiment 1n. The detector 51 of this embodiment is installed so as to monitor the vicinity of the automatic door 82, and when a person enters the field of view, sends a detection signal to the motor control unit 83 to drive the motor 84. And open the automatic door 82. Such an automatic door configuration is suitable for retrofitting, since the detector can operate on battery power and there are few restrictions on the mounting location as described above.

 (1 o) Example 1 o

 FIG. 24 is a configuration and a circuit diagram of the detection device according to the embodiment 1o, and FIG. 25 is a time chart of the operation.

 The receiving field of view 1 is composed of the lens 1 16 and the PD 1 of the two-part PD 131, and the receiving field of view 2 is composed of the lens 1 16 and the PD 2 of the two-part PD 131, and the lens 1 17 The receiving field of view 3 is composed of the PD 3 of the two-part PD 1 32, and the receiving field of view 4 is composed of the lens 1 17 and the PD 4 of the two-part PD 132. These fields are illuminated by natural scattered light (illumination light, sunlight, etc.) from the surroundings.

Each PD outputs a photocurrent according to the light input power to the PD, I 1 from PD 1, I 2 from PD 2, and PD 3 Outputs I 3 and PD 4 outputs I 4. These photocurrents are converted to voltages by the I conversion circuit. V 3 and 14 are converted to V 4 by the I ZV conversion circuit 124. The voltages V 1 and V 2 are subtracted by the differential amplifier circuit 107 to obtain (V 1 —V 2), and the voltages V 3 and V 4 are subtracted by the differential amplifier circuit 108 to obtain (V 3 — V 4). Here, VI to V4 include noise such as the offset voltage of the operational amplifier, the power supply low-frequency noise included in the fluorescent lamp, and the high-frequency noise generated in the light-receiving element / light-receiving circuit. Since the DC component is dominant in the received light signal, it is difficult to remove the offset voltage and low-frequency noise.

Therefore, by periodically switching the analog switches 91 to 94 inserted in the output lines of the light receiving elements with the pulse signal SG, the output from each light receiving element is converted from a DC signal to a pulse signal. Convert. In this case, the output signal waveforms of operational amplifiers 1, 4 and 2, 3 of each IZV conversion circuit are shown in Figures 25c and 25d. These signals are passed through a high-pass filter (HPF1 to HPF4) composed of capacitors C1 to C4 and resistors R5 to R8 to remove offset voltage and low-frequency noise. The signal waveforms are shown in Figure 25e and 25 2. In addition, high frequency noise is removed by a port-pass filter composed of capacitors C5 to C6 and resistors R9 to R10. The signal waveforms of the operational amplifiers 5 and 6 are shown in Figures 25g and 25h. Noy These noise-removed signals are further subtracted by the differential amplifier circuit 109, and the output is

 (Output) = (V 1-V 2) one (V 3-V 4)

 Becomes The signal waveform is shown in Figure 25i. This result is compared with a preset threshold value by a comparator circuit 110, passes through an integration circuit 112 for noise removal, and is output from an output circuit 113. Specific examples of the comparison circuit 110, the integration circuit 112, and the output circuit 113 will be described later.

In the above configuration, when there is no object to be detected, the background image illuminated by natural scattered light is reflected on the two divided PDs 13 1 and 13 2 through the lenses 1 16 and 1 17. When there is no contrast in the background, the amount of light incident on PD 1 and PD 2 and the amount of light incident on PD 3 and PD 4 are equal, and the output of the differential amplifier circuit 109 becomes 0. If there is a contrast, the amount of light incident on PD 1 and PD 2 and the amount of light incident on PD 3 and PD 4 are different, and the output of the differential amplifier circuit 109 does not become 0, and Depending on the relationship between the background and the reflectance of the detection object 15, the output of the differential amplifier circuit 109 takes both positive and negative values. Therefore, the sensitivity setting circuit 95 sets the output V 0 in the absence of the detection object 15 so that it is the center between the threshold values V thl and V th2 (see Fig. 25i). The sensitivity can be set using a variable resistor or by setting the differential output V 0 to AZD conversion and using a microcomputer. In addition, the sensitivity setting may be performed inside or outside the detection device. Here, if a detection object with a reflectance equal to or higher than that of the background is in the light-receiving fields of view 1 and 4, the light reflected from the detection object will be larger than the light reflected from the background. The light intensity P in the part where the image of the object is reflected is large, and the light intensity P in the part where the background is reflected is small. Therefore,

 (V1-V2)> 0, (V3-V4) <0, and the output of the differential amplifier circuit 109 becomes Vthl or more, which is different from the initial state. Detects intrusion. .

 In addition, if there is a detected object with low reflectance equal to or lower than that of the background in the light-receiving fields 1 and 4, the reflected light from the detected object will be smaller than the reflected light from the background. The light intensity の at the part where the image of the object is reflected is small, and the light intensity の at the part where the background is reflected is large. Therefore,

 (V I — V 2) <0, (V 3 — V 4)> 0, and

Since the output of the differential amplifier circuit 109 becomes Vth2 or less, which is different from the initial state, the intrusion of an object is detected by detecting this difference.

As described above, according to the detection apparatus of the present embodiment, when an object that does not emit light by itself and operates using natural scattered light as a light source and an object that did not exist in the initial state enters the light receiving visual field, the two-divided PD is used. Since the balance of the amount of light entering the device is lost, the amount of change is detected, and the presence or absence of the detected object is detected, so that current consumption can be easily reduced. Also, if there is a change in any of the light receiving fields 1, 2, 3, 4 Since the detection signal is output, the field of view of the received light can be widened and a large object can be detected compared to the case where only one photodetector is used. The sensitivity is also doubled.

 FIG. 26 shows specific examples of the comparison circuit 110, the integration circuit 112, and the output circuit 113. These circuits constitute a determination unit based on an integration method for obtaining a more reliable binary output from the pulse signal output of the differential amplifier circuit 109. The variable resistor VR at the input terminal of the comparison circuit 110 corresponds to the sensitivity adjustment circuit 95, and can change the threshold value (ON / OFF level). The substantial content of the output circuit 113 is a comparison circuit 113a. FIG. 27a to FIG. 27d are timing charts of the operation. When the output of the differential amplifier circuit 109 exceeds the threshold value 0N level, the output of the COM 3 of the comparator circuit 110 becomes L. At this time, the transistor TR5 of the integration circuit 112 is turned on by INV1, and the capacitor C2 is charged by the current I '. When the output of the differential amplifier circuit 109 falls below the threshold OFF level, the output of COM3 goes high. At this time, the transistor TR5 is in the OFF state due to INV1, and the charge of the capacitor C2 is discharged at a predetermined time constant (C2x, R13) through the resistor R13.

By employing the above configuration, when the output of the differential amplifier circuit 109 continuously exceeds the ON level a predetermined number of times, the output of the comparison circuit 113a changes. Charge and discharge of integration circuit 1 1 2 Since the output of the differential amplifier circuit 109 is temporarily lower than the ON level of the comparator circuit 110 due to disturbance during the signal period, The output of circuit 1 13 a remains ON. As described above, since the signal is binarized for each pulse, the signal does not respond to an impulse noise having a small pulse width and a large wave height, thereby eliminating a malfunction due to the pulse width. Note that the embodiment shown in Fig. 24 above introduces a Chiotsuba-type amplifier known as a technique for removing the effects of offset generated by a general signal processing circuit and low-frequency noise. Although apparently similar to the above, the Chitsubasa-type amplifier has a smoothing section for DC conversion on the output side, whereas the present embodiment does not use a smoothing section and has a binary value as shown in FIG. The difference is that a judgment unit including a comparison circuit for obtaining an output is used. For this reason, in the present embodiment, a specific effect of preventing malfunction due to impulse noise as described above can be obtained.

Next, FIG. 28 shows a modified example of the judgment unit of the integration method. The time chart of the operation is shown in Figs. 29a to 29e. When the output of C0M1 of the comparison circuit 110 is L and the pulse signal SG is H, the transistor TR1 is in the 0N state and AND1 is in the L level, so that the transistor TR4 is in the OFF state. Therefore, the capacitor C 1 is charged by the current I ′. When the output of COM1 is H and the pulse signal SG is H, the transistor TR1 is in the 0FF state and AND1 is at the H level, so that the transistor TR4 is in the ON state. The charge of the capacitor C1 is discharged at once through the transistor TR4.

 The comparator circuit 110 outputs an L level when the output of the differential amplifier circuit 109 exceeds a predetermined threshold value 0 N level, and outputs a predetermined threshold value 0 FF level If the value is lower than, the H level is output. The integrator circuit 112 is charged when the output signal of the comparison circuit 110 is at the L level, and the charged potential of the capacitor C1 changes from 0 [V] to Va (point (1) c in Fig. 29c). After that, it is discharged with a predetermined time constant (C 1 XR 5), and the charging potential changes from Va to Vb (Vb> 0) by the next input signal (point ② in Figure 29c). The input changes from Vb to Va + Vb (point c in Fig. 29c), and if the output of the comparison circuit 110 is at the H level, the integration circuit 112 continues to be charged. On the other hand, if the output of the comparison circuit 110 is at the L level (the point in FIG. 29c), the integration circuit 112 is discharged at once, and becomes 0 [V]. If the output signal of the integration circuit 112 exceeds the predetermined threshold ON level, the comparison circuit 113a outputs an H level to detect the presence of an object or the like.

By having such a judgment unit, as shown in FIG. 29a to FIG. 29e, when the signal is not in the signal period, the signal comes close to the signal and there is a disturbance. Even if the output temporarily exceeds the ON level of the comparison circuit 110, the output of the comparison circuit 113a does not go to 0 N, and an accurate binary output can be obtained. In other words, adopt the configuration shown in Figure 28 Therefore, if there is a signal of a predetermined size or more for a predetermined period, the output will be

When turned ON, the process can be performed without being affected by the signal history immediately before the predetermined period, and the conditions for turning ON and OFF the output can be set independently.

 FIG. 30 shows another example of the judgment unit. This determination unit is a pulse power counting system, and the comparison circuit 110 and the determination unit 96

(Functioning as a digital filter). Figure 31a to Figure 311 show the time chart of the operation. When the output of the differential amplifier circuit 109 has an input that exceeds the 0 N level T h (ON) = R 2 x (I 1 + I 2), the comparison circuit 110 The output goes to H level. If the output of the differential amplifier circuit 109 has an input lower than the OF F level T h (O F F) = R 2 × I 1, the output of the COM 1 goes to the L level.

In the discriminator 96, the RS latch 1 has Q 0 = H when the output signal of COM 1 is H. Then, Q 0 is reset by the RST signal (Fig. 31c), becomes L level, and waits for the next input signal. When the output signal of CAM1 is L, Q0 = L, and it is reset by RST and maintains L level. D—FF 1 to 3 are at the rising edge of clock CK, Q = H if D input is H level, L = D input, and Q = L if D input. Since AND1 outputs AND of Ql to Q3, all of Q1 to Q3 are at the H level. That is, as shown in (3) in Fig. 31a, a predetermined number of times, and here, C3 Signal above the 0 M1 threshold level When input, the output of AND 1 changes to H level. AND 2 outputs AND of inverted Q 1 to inverted Q 3, so all inverted Q 1 to inverted Q 3 are at H level, that is, when there is no input, they are at H level, but at least once If there is an input, it will be at L level, and it will be at L level for at least three cycles. R—S Latch 2 outputs Q 4 = H when AND 1 is at the H level, that is, when there are three consecutive input signals. Inverting Q 4 sets the threshold level of COM 1 to T h ( 0 N) to T h (OFF). In this example, the same advantages as in the case of FIG. 28 are obtained.

 (2) Second embodiment

Hereinafter, a second embodiment will be described with reference to the drawings. In the second embodiment, a description will be given of a passive detection device that can be used for other purposes, including the detection device of the first embodiment. FIG. 32 is a diagram showing the basic configuration of a passive-type detection device. Referring to FIG. 32, the passive detector 200 includes a detecting element 211, an analog switch 211 receiving a detecting element switching signal SG, an IZV converter 211, and a high-pass filter. The filter includes a filter 2 14, an amplifier 2 15, a low-pass filter 2 16 and a decision unit 2 17. The physical quantity to be detected is detected by the detection element 211, and the detection output is periodically intermittently turned into a pulse signal by the analog switch 212, and is converted from the current to the voltage by the IZV converter 211. And then passed through the high-pass filter 2 14, the amplifier 2 15 and the low-pass filter 2 16 The signal is processed and given to the judgment unit 217. The judging unit 217 outputs the state of the detection target from each pulse signal in binary. Note that the no-pass filter and the two-pass filter pass signals in the band including the switching frequency of the analog switch and allow offsets and external signals generated in the signal processing circuit to pass. Low frequency noise and high frequency noise.

 Hereinafter, a photodetector embodying the passive type detection device will be described.

 (2a) Example 2a

 The configuration of the photodetector according to the embodiment 2a is shown in Fig. 33, and its time chart is shown in Figs. 34a to 34h. The detecting section 220 is composed of two light receiving elements (photodiodes: PD 1 and PD 2) as detecting elements 211 and two lenses 201 and 202, respectively. Light-receiving field 1 and light-receiving field 2 are configured. These fields of view are separated from each other and illuminated by natural scattered light (light from sunlight, fluorescent lights, etc.). In addition, light receiving circuits such as the IZV converters 2 13a and 2 13b, differential amplifiers 2 15 and filter circuits 2 14 and 16 and a comparison circuit 2 1 8. The supply of power (Vs.Vr) to the discriminator 219 is performed by switching signal PG (period:

The switching is performed intermittently by switching the analog switches 2 12 c and 2 12 d (Fig. 34c) using the T, dew, and tee ratios tp ZT) to reduce the current consumption of the circuit.

PD 1 and PD 2 output the photocurrent according to the incident light, The photocurrent is switched by the analog switches 211a and 212b using the switching signal SG (period: T, duty ratio ts / T, synchronized with PG) (Fig. 34b). The switched photocurrent is converted to a voltage by the IZV converters 21a and 21b, respectively. The light receiving signals of PD1 and PD2, which dominates the DC component, include the offset voltage generated by the operational amplifiers of the low-frequency noise of the AC power supply and the I / V converters 213a and 213b. In order to remove noise, the received signal is given a high-frequency component by switching as shown above (Fig. 34d), and the high-pass filter at the subsequent stage is used.

The low frequency noise is removed by HPF 2 14 a and 2 14 b (FIGS. 34 e and 34 f). At this time, by setting the cut-off frequency of this high-pass filter lower than the switching signal SG and higher than the switching signal PG, it is possible to remove the offset voltage and power supply low-frequency noise, Can only be taken out.

The two light receiving signals (V 1, V 2) from which the low-frequency noise has been removed are differentially amplified by the differential amplifier 215 to obtain (V 1 −V 2) (FIG. 34 g). After that, the low-frequency noise is removed again by the high-pass filter HPF214c, and the high-frequency noise is removed by the single-pass filter LPF216, and the signal is as shown in Fig. 34h. This signal is compared with a preset threshold value by the comparison circuit 218. The cut-off frequency of the mouth-to-mouth filter is determined by the switching signal SG, Higher than switching signal PG.

 Here, if a person or an object enters only the light receiving field 1, more light enters the PD 1 than the PD 2 and (V 1 −V 2) increases. When this (VI-V 2) exceeds the threshold value, the comparison circuit 218 outputs an ON signal, and based on the result, the discriminating unit 219 removes noise to remove the presence of a person or an object. It outputs a signal that informs the user. As described above, in the passive-type light detection device, by switching the light-receiving element and removing the noise using the filter circuit at the subsequent stage, it is possible to easily and reliably extract a light-receiving signal with a high SZN ratio. It becomes possible.

 (2b) Example 2b

Next, Embodiment 2b in which the ON / OFF cycle and the duty ratio of the switch stage are made variable will be described with reference to FIGS. 35A to 37. FIG. Fig. 35a shows a configuration example of a variable cycle duty ratio circuit that generates the switching signal SG, and Fig. 35b shows its time chart. This circuit consists of a current source 231, a capacitor CO charged by the current source, a comparator COM1 that outputs a switching signal SG, etc., and a capacitor charged by the current I of the current source 231. The potential V of the capacitor C 0 becomes the potential of the negative input terminal of COM 1. Assuming that the threshold at which COM 1 turns on is VI and the threshold at which 0 FF is turned off is V 2, if the potential V is between V 2 and V 1, the output of C 0 M 1 is H And the switching signal SG is H. At this time, transistor TR1 is ON and transistor TR2 Is 0 FF. This time is the charging time t1.

 When the potential V rises due to the charging of the capacitor C0 and reaches V1, the output of COM1 becomes L, and the switching signal SG becomes L. At this time, the transistor TR 1 is OFF and the transistor TR 2 is ON. When the transistor T R2 is turned on, the charge stored in the capacitor C O is discharged through the resistor R5 with a time constant (C 0 X R 5). The potential V of the capacitor C 0 gradually decreases until it reaches V 2. This time is the discharge time t 2. When the potential V reaches V2, the output of COM1 becomes H as described above, and the switching signal SG becomes H. In this way, the switching signal SG becomes H during the charging time t1 of the capacitor C0, becomes L during the discharging time t2 of the capacitor C20, and repeats the oscillation. Voltages V 1 and V 2, current I and charging time t 1 can be expressed by the following equations.

 V 1 = R 2 / (R 2 + R 1 // R 3)

 V 2 = (R 2 / / 3) / (R 1 + R 2 // R 3)

 I = {Vs-Vbe (TR4)} / R6

 t l = C 0 x (V 1-V 2) / I

 Note that R 1 // R 3 and the like represent the parallel resistance of the resistor R 1 and the resistor R 3, and V and be (TR 4) represent the base emitter potential of the transistor TR 4. V s is the power supply voltage.

By the way, FIG. 35a shows that the current value I of the current source 231 can be changed by the value of the variable resistor R26. formula (1) and (2) show that the charging time tl to the capacitor C 20 can be changed by the current I. Therefore, the cycle (t1 + t2) of the switching signal SG and the pulse duty ratio tlZ (tl + t2) can be changed by the value of the variable resistor R6.

 FIG. 36 shows the configuration of the detection device according to the second embodiment, in which the pulse signal SG and the filter frequency of the high-pass filter HPF 214 are interlocked and variable. As the switching signal SG, the output of the circuit shown in FIG. 35A may be used. In order to make the filter frequency variable, current source 2 3 1 binding 0] ^ 1 to 3, analog switch 2 12 b to 2 12 d, capacitor connected in parallel with capacitor C 1 C 2, C 3 and C 4 are used. The input voltage V 0 of C 0 M 1 to 3 can be changed by the value of the variable resistor R 6. The cutoff frequency f of the HPF 214 is determined by the parallel capacitance C i of the capacitors C 1 to C 4 and the resistor R 8, and V 0, which is the negative input voltage of COM 1 to 3, is as follows: Can be expressed.

 f = 1/2 ^ R8 C i

 V 0 = I X R 1 1

FIG. 37 shows the relationship between the state of each part of the circuit and the parallel capacitance C i of the capacitors C 1 to C 4. The cut-off frequency f of the HPF 2 14 is controlled by the ONZO FF control of the analog switches 2 12 b to 2 12 d controlled according to the voltage V 0, and the connection state of the capacitors C 1 to C 4 Is determined, thereby parallel It can be changed by changing the value of the capacitance C i. For example, if the variable resistor R6 is made larger, the current I becomes smaller, the charging time t1 becomes longer, and the frequency of the switching signal SG becomes smaller. Further, the voltage V 0 decreases, the parallel capacitance C i increases, and the cutoff frequency の of the HPF 214 also decreases in conjunction with the frequency of the switching signal SG. On the other hand, if the resistance R6 is reduced, the current I increases, the charging time t1 decreases, and the frequency of the switching signal SG increases. Further, the voltage V 0 increases, the parallel capacitance C i decreases, and the cut-off frequency f of the HPF 214 increases in conjunction with the frequency of the switching signal SG.

 As described above, in this embodiment, since the period and the duty ratio of the switching signal SG can be freely changed, the external noise is reliably removed by setting the frequency to be different from the external noise in the use environment. It is possible to prevent a malfunction caused by the above.

Further, FIG. 38 shows a specific example of the comparison circuit 218 and the judgment unit 219 which constitute the above judgment unit. These circuits constitute a judgment unit based on the integration method for obtaining a more reliable binary output from the pulse signal output of the LPF 2 16. The variable resistor VR at the input terminal of the comparison circuit 218 corresponds to the sensitivity adjustment circuit, and the threshold value (ON / OFF level) can be changed. The discriminating unit 219 includes an integrating circuit 219a and a comparing circuit 219b. Fig. 39a to Fig. 39d are operation time charts. When the output of the LPF 216 exceeds the threshold ON level, the output of the COM 3 of the comparison circuit 218 becomes L. Then I

The transistor TR 5 of the integrating circuit 2 19 a

In the ON state, the capacitor C2 is charged by the current I '. When the output of LPF2 16 falls below the threshold OFF level,

The output of COM 3 becomes H. At this time, the transistor TR5 is in the 0 FF state due to I NV1, and the charged charge of the capacitor C2 passes through the resistor R13 to a predetermined time constant (C2XR1

Discharged in 3).

 By adopting the above configuration, when the output of LPF216 continuously exceeds the ON level a predetermined number of times, the comparison circuit 2

The output of 19 b changes. Since the charge and discharge of the integration circuit 2 19 a are slow, there is a disturbance during the signal period, and L P F 2 1

Even if the output of 6 temporarily drops below the ON level of the comparison circuit 218, the output of the comparison circuit 219b remains ON. In this way, the signal is binarized and handled for each pulse, so it does not react to impulse noise having a small pulse width and a large wave height, and the malfunction due to it is eliminated. Note that the embodiment shown in FIG. 36 described above is known as a technique for removing the effects of offset and low-frequency noise generated in a general signal processing circuit, as in the previous embodiment. At first glance, this is similar to the one using a Chipotle-type amplifier.However, the Chipotter-type amplifier has a smoothing part on the output side for DC conversion, but in this embodiment, no smoothing part is used. Binary values as shown in Figure 3 8 The difference is that a judgment unit including a comparison circuit for obtaining an output is used. For this reason, in the present embodiment, a specific effect of preventing malfunction due to impulse noise as described above can be obtained. Next, FIG. 40 shows a modified example of the judgment unit of the integration method. The time chart of the operation is shown in Figs. 41a to 41e. When the output of COM1 of the comparison circuit 218 is L and the switching signal SG is H, the transistor TR1 is in the 0N state and AND1 is in the L level, so that the transistor TR4 is in the OFF state. Thus, the capacitor C1 is charged by the current I '. When the output of COM1 is H and the switching signal SG is H, the transistor TR1 is in the 0FF state and AND1 is in the H level, so that the transistor TR4 is in the 0N state, and thus the capacitor is The charge of C1 is discharged at once through the transistor TR4.

The comparison circuit 218 outputs the L level when the output of the LPF 216 exceeds the preset threshold ON level, and outputs the L level when the output is below the preset threshold 0 FF level. Outputs H level. The integrator circuit 219a is charged when the output signal of the comparator circuit 218 is at the L level, and the charged potential of the capacitor C1 changes from 0 [V] to Va (point cc in FIG. 41). After that, the battery is discharged with a predetermined time constant (C 1 XR 5), and the charged potential changes from Va to Vb (Vb> 0) by the next input signal (② point in FIG. 41 c). The input changes from Vb to Va + Vb (point 3 in Fig. 4 1c), and the output of the comparison circuit 2 18 If it is at the H level, the integration circuit 2 19 a continues to be charged. On the other hand, if the output of the comparison circuit 218 is at the L level (the point in FIG. 41 c), the integration circuit 219 a is discharged at once and becomes 0 [V]. If the output signal of the integration circuit 219b exceeds the preset threshold ON level, the comparison circuit 219b outputs an H level to detect the presence of an object or the like.

 By having such a determination unit, as shown in FIG. 41, when the signal is not in the signal period, the signal comes close to the signal and there is a disturbance, and the output of the LPF 216 is temporarily changed to the comparison circuit 218. Even if the ON level exceeds the ON level, the output of the comparison circuit 219b does not go to 0 N, and an accurate binary output can be obtained. In other words, by adopting the configuration of FIG. 40, when a signal having a magnitude equal to or greater than a predetermined value is provided for a predetermined period, the process of setting the output to 0 N affects the signal history immediately before the predetermined period. This has the advantage that the conditions for turning on and off the output can be set independently.

Fig. 42 shows another example of the judgment unit. This judging unit is of a pulse count type and is composed of a comparing circuit 218 and a judging unit 219 (which functions as a digital filter). The time chart for the operation is shown in Figs. When the output of the LPF 2 16 has an input higher than the 0 N level Th (ON) = R 2 x (I 1 + I 2), the output of the COM 1 changes to the H level. Become. LPF2 16 output is off level T h (OFF) = below R 2 x I 1 When there is a rotating input, the output of COM 1 goes to L level. In the discriminator 219, the RS latch 1 has Q 0 = H when the output signal of COM 1 is H. Then, Q 0 is reset by the RST signal (Fig. 43c), becomes L level, and waits for the next input signal. When the output signal of CAM1 is L, Q0 = L, and it is reset by RST and maintains L level. D—FF 1 to 3 are at the rising edge of clock CK, Q = H if the D input is H level, and Q = L if the D input is L level. AND 1 outputs AND of Q 1 to Q 3, so that all of Q 1 to Q 3 are at the H level, that is, a predetermined number of times, as shown in (1) and (3) in FIG. When a signal that exceeds the threshold level of COM 1 is input, the output of AND 1 changes to H level. AND 2 outputs AND of inverted Q 1 to inverted Q 3, so once inverted Q 1 to inverted Q 3 are all at H level, that is, once there is no input, they are at H level once. However, if there is an input, it will be at the L level, and at least three cycles will be at the L level. The R-S latch 2 outputs Q 4 = H when AND 1 is at the H level, that is, when there are three consecutive input signals, and the inverted level of Q 4 causes the threshold level of C 0 M 1 to be T h ( ON), then T h (OFF). Also in this example, the same advantages as in the case of FIG. 40 can be obtained.

 (2c) Example 2c

FIG. 4 shows a configuration of an infrared detector according to Embodiment 2c of the present invention. Shown in The thermopile 211a, which is an infrared detecting element of the detecting section 220, is an element that can obtain an electromotive force according to the amount of infrared light. When a person enters the detection area, the infrared radiation emitted from the person is detected by the thermopile 211a, and is switched by a switching signal SG (frequency ί) at the analog switch 212 via a buffer. Is cut. The switched signal passes through the HPF 21 whose cut-off frequency is lower than the switching frequency f, and is amplified by the amplifier 215. The amplified signal passes through the LPF 216 whose cut-off frequency is higher than the switching frequency ί. If the cut-off frequency exceeds the threshold value, the comparison circuit 218 outputs a 0 Ν signal. It is determined whether there is any intrusion and existence of, and it is output.

 (2d) Example 2d

 FIG. 45 shows the configuration of the detection unit of the temperature detector according to Embodiment 2d of the present invention. The configuration downstream of the detection unit may be the same as in Fig. 36. The temperature thermistor Rth of the temperature detection element shown in the figure is an element whose resistance value changes according to the temperature. The change is detected as a voltage value V 0 and used for temperature control and the like. Since the detection result is binarized and output, it can be used to perform on / off control over the night. Further, a thermocouple or the like may be used as the temperature detector. The output voltage V 0 at the connection point between the temperature thermistor R th and the resistor R can be expressed by the following equation. However, Vs is the power supply voltage.

V 0 = {R / (R th + R)} V s (2 e) Example 2 e

 Fig. 46a and 46b show the configuration of the pressure detector according to Embodiment 2e of the present invention, Fig. 46c shows the equivalent circuit, Fig. 46d shows the signal processing unit, and Fig. 46 shows the time chart. 47a to 47h. This detector is used for fluid pressure control. As shown in FIGS. 46a and 46b, the pressure sensing element is provided with a pressure-sensitive diaphragm 22 on an Si single crystal substrate 221, and a strain gauge (diffusion resistance) R l, R In this configuration, 2, R3 and R4 are arranged. Regarding the strain due to the pressure of the strain gauge, the rate of change of the radial gauges Rl and R3 is greater than the rate of change of the circumferential gauges R2 and R4. This difference is detected by the wheel bridge shown in the equivalent circuit of Fig. 46c, processed by the signal processing unit shown in Fig. 46d, and output. The output voltage V 0 of this equivalent circuit can be expressed by the following equation.

 V 0 = (V 1-V 2)

 = (R 4 / (R 1 + R 4)-R 3 / (R 2 + R

 3)} V 1

When pressure is applied to the detector, the resistance changes as described above, causing the potential of VI to drop (Fig. 47c) and conversely, the potential of V2 to rise (Fig. 47d). . VI is analog switch 2 12a and V 2 is analog switch 2 12b. (Figures 47e and 47f :). After that, it is amplified by the differential amplifier 2 15 (Fig. 47g), and the high-frequency noise is removed by the LPF 216 (Fig. 47h). If the detection signal exceeds the threshold value, the comparison circuit 218 outputs an ON signal, and the judgment unit 219 judges whether the pressure is higher or lower than the set value, and outputs the result. This pressure detector can be applied to the detection of abnormal pressure reduction due to the opening of city gas valves.

 (2 f) Example 2 f

FIG. 48 shows the configuration of the detection unit of the humidity sensor according to Embodiment 2f of the present invention. The configuration subsequent to the detection unit may be the same as in FIG. 46d. This detector can be used for controlling air conditioners. The detection sensor element 2 25 (R 1) is arranged in the air to be detected, and the compensation sensor element 2 26 (R 4) is arranged in the dry air. These elements 2 25 and 2 26 are elements whose resistance changes according to the humidity. They are bridge-connected together with the other resistors R 2 and R 3. Is converted to a voltage value V 0 and output. The output of this humidity sensor can be used for on / off control of the humidifier. A gas sensor replaces this humidity detection element with an element whose resistance changes according to the mixture ratio of the gas mixture, and is used for controlling the gas mixture and detecting gas leakage. In this case, the detection sensor element 225 (R, l) is disposed in the gas to be detected, and the compensation sensor element 226 (R4) is disposed in the reference gas. The change amount of the resistance value is detected after being converted into the voltage value V 0. This gas sensor can be used as a city gas leak sensor. (2 g) Example 2 g

 FIG. 49 shows a configuration according to Example 2g of the present invention. In this example, a switch 211a for switching a detection signal from the detection element 211 is constituted by an FET (field effect transistor). According to this configuration, switching can be performed at a high speed, and since there is almost no leakage current, a very small amount can be detected. In addition, the power consumption of FET can be reduced because of voltage control.

 (2h) Example 2h

 FIG. 50 shows a configuration according to Example 2h of the present invention. In this example, a switch 212b for switching a detection signal from the detection element 211 is constituted by a bipolar transistor. According to this configuration, there is an effect that spike noise due to switching is small.

 (3) Third embodiment

 Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

 (3a) Example 3a

FIG. 51 is a block diagram of the detector according to the embodiment 3a, and FIGS. 52a to 52i are time charts showing the operation of the detector. The detector 301 receives the background 14 of natural scattered light (for example, lighting equipment and sunlight) at the place where the detector 301 is placed and the reflected light from the detection object 15 to detect the object. It is a passive type detector that detects presence / absence. The detector 301 includes a light-receiving lens 303 as a light-receiving unit, It is composed of a two-division photo diode 3, 02 (light receiving element, hereinafter abbreviated as PD1, PD2) provided behind the light receiving lens 303, and the first and second light receiving fields are provided. It is composed. FIG. 51 shows a state in which the detection object 15 has entered one of the two light receiving visual fields (the visual field 2).

 Normally, reflected light from the background (for example, all over white) 14 passes through the lens 303? 0 1, incident on PD2. The light incident on PD 1 and PD 2 is converted to light-to-current here, and the detection current I 1 from PD 1 and the detection current I 2 from PD 2 are intermittently switched by switches SW 1 and SW 2. It is sent to the light receiving circuit 308. The switches SW1 and SW2 are connected to the oscillation circuit 3

Oscillation pulse signals SG1 and SG2 supplied from 07 are switched alternately by the clock of SG1 and SG2, so that the currents I1 and I2 passing through the switches SW1 and SW2 are switched. Timing 2 is asynchronous and time division. Detection current I 1,

12 is converted into a voltage by the light receiving circuit 308 and then amplified by the amplifying circuit 309 to become detection voltages V 1 and V 2. The voltages V 1 and V 2 are sampled by the SZH circuit 310 at the timing of the sample and hold signal SH of the oscillation circuit 307, and then converted to digital signals by the A / D conversion circuit 311. And outputs Dl, D2, respectively. These outputs Dl and D2 are subjected to a difference operation (D1-D2) in the operation unit 312 to obtain an operation result D. Threshold value that differentiates the level above and below this operation result D

(VT 1, VT 2) is set in the threshold setting circuit 3 1 4 O

 Now, when the detection object (one black surface) 15 enters the field of view 2, the amount of light entering the PD 2 decreases and D 2 decreases. At this time, the operation result D by the operation unit becomes larger than the previous D. This is compared with the above threshold value (VT1, VT2) in the comparison circuit 316. When the output D exceeds VT1 or falls below VT2 as shown in FIG. 16 0N signal is output. This ON signal passes through an integration circuit 317 to remove noise, and is then output from the output circuit 318 to the outside of the detector 301 as an ONZO FF signal. The integrator circuit 317 outputs the 0N signal when the number of consecutive 0N signals of the comparison circuit 316 becomes three or more, and the 0FF signal of the comparison circuit 316 output continues. If the number becomes three or more, a 0FF signal is output.

In this way, two systems of detection signals (11, 12) are alternately switched, and each detection signal is processed as a pair and processed by one system of signal processing circuit. This eliminates the need for the same number of light-receiving circuits, amplifier circuits, SZH circuits, AZD conversion circuits, etc. as the number of light-receiving outputs, thus reducing the size of the signal processing circuit, reducing the number of circuit components and reducing current consumption. It is possible to reduce the size, the size, the cost, and the manufacturing defect rate. Further, by simplifying the circuit configuration, it is not necessary to match the characteristics of a plurality of circuits, so that high-precision components are not required. Also, In this configuration, detection is performed by a passive method that does not require a light emission current, so that current consumption can be reduced. In addition, by reducing the current consumption, the life of the battery can be extended when the battery is driven.

 (3b) Example 3b

 FIG. 53 is a block diagram of a detector according to Example 3b. This detector 320 is different from the detector 301 shown in FIG. 51 in that the switches SW 1 and SW 2 provided between the PD 1 and PD 2 and the light receiving circuit 308 are replaced by This is provided between the amplifier circuit 309 and the SH circuit 310. After the detection currents I 1 and I 2 from PD 1 and PD 2 are converted to voltages by the respective light receiving circuits 3 08 a and 3 08 b and amplified by the amplifier circuits 3 0 9 a and 3 09 b , And are switched alternately by switches SW1 and SW2 in accordance with the clocks of signals SG1 and SG2, and become voltages VI and V2. In this way, switching is performed after amplifying the detection signal in the amplifier circuits 309a and 309b, thereby switching to a high impedance line (small signal line). Since no element is required, switching noise superimposed on the received light signal can be reduced.

 (3c), Example 3c

FIG. 5 is a configuration diagram near the switch of the detector according to Example 3c. In Example 3c, the switch SW is constituted by a field-effect transistor (hereinafter, referred to as FET). This As a result, high-speed switching becomes possible, and since there is almost no leakage current, a minute change in the detection current can be detected, and the presence or absence of an object can be detected more accurately. In addition, since the FET is controlled by voltage, current consumption can be further reduced.

 (3d) Example 3d

 FIG. 55 is a configuration diagram near the switch SW of the detector according to Example 3d. In this embodiment, the switch SW is constituted by a bipolar transistor. Since the bipolar transistor has a small spike noise due to switching, it can detect minute changes in the detection current, and can more accurately detect the presence or absence of an object.

 (3 e) Example 3 e

FIG. 56 is a block diagram of the detector 3221 according to the third embodiment 3e, and FIGS. 57a to 57m are time charts of the operation of the detector. This detector 3221 is obtained by switching the switch SW2 in the detector 301 shown in FIG. 51 described above by ANDing the signal SG2 with the output signal of the second comparison circuit 322. That's what I did. The light received by PD 1 and PD 2 is converted into detection currents 11 and 12, and the currents II and I 2 are supplied to the light receiving circuit 308, the amplifying circuit 309, After passing through the SZH circuit 310 and the AZD conversion circuit 311, the outputs become D 1 and D 2. Here, the output D1 is input to the second comparison circuit 32, and the value of the output D1 is sampled. If they are different before and after one evening, the comparator circuit 3 2 2 outputs an ON signal. Switch SW 2 is switched by ANDing this output signal with signal SG 2. On the other hand, the output D 2 continues to output the previous data until the release signal due to the ON signal of the second comparison circuit 32 2 is input by the data holding circuit 32 3, and the second comparison circuit 32 2 When the release signal by the 0 N signal is input, the data held in the data holding circuit 3 2 3 is updated. The output D 2 and the output D 1 are subjected to a differential operation in the operation unit 3 12 to obtain an operation result D. The calculation result D is compared with threshold values VT 1 and VT 2 set in advance by the comparison circuit 316. The comparison circuit 316 outputs the 0N signal when the operation result D exceeds VT1 or falls below VT2. If the number of 0 N signals becomes three or more in succession, a binary ON signal is obtained from the integrating circuit 3 17, and this signal is output from the output circuit 3 18 and the detector 3 2 1 Inform the outside that the object 15 has entered the field of view.

As described above, since the signal (I 1) of one path (SW 1) is monitored, and if there is a change, the other path (SW 2) is operated. The current consumption can be further reduced as compared with 301. Also, since the two detection signals (I1, I2) obtained by the passive and sieve methods are processed by the signal processing circuit including one light receiving circuit, the scale of the signal processing circuit can be reduced. The same operation and effect as those of the first embodiment can be obtained. (3 f) Example 3 f

 FIG. 58 is a block diagram of the detector 32 6 according to the embodiment 3f, and FIGS. 59a to 59i are time charts of the operation of the detector. The detector 326 is obtained by adding a modulation circuit 328 to the detector 301 shown in FIG. 51 described above. The modulation circuit 328 performs pulse time modulation of sg1, sg2, sh, and a / d sine waves supplied from the oscillation circuit 327, and generates pulse signals of SG1, SG2, SH, and AZD. Is converted to.

The light incident on PD 1 and PD 2 is converted to light-to-current here, and the detection current I 1 from PD 1 and the detection current 12 from PD 2 are intermittent at switches SW 1 and SW 2 Is sent to the light receiving circuit 308. The switches SW1 and SW2 are alternately switched by the clock of the oscillating pulse signals SG1 and SG2 supplied from the oscillating circuit 307, whereby the switches SW1 and SW2 are switched. 1, The timing of currents I31 and I32 passing through SW2 is asynchronous and time-division. The detection currents I 1 and I 2 are converted into voltages by the light receiving circuit 308 and then amplified by the amplifier circuit 309 to become the detection voltages V 1 and V 2. These voltages VI and V2 are sampled by the SZH circuit 310 at the timing of the sample and hold signal SH of the oscillation circuit 307, and then converted to digital signals by the AZD conversion circuit 311. The outputs are Dl and D2, respectively. These outputs D l and D 2 are subjected to a difference operation (D 1 — D 2) in the operation section 3 1 2, and the operation result D is obtained. obtain. This value D is compared with the threshold value VT by the comparison circuit 316, and if it exceeds VT, the 0N signal is output. If the number of ON signals becomes three or more in succession, a binarized 0 N signal is obtained from the integrating circuit 3 17, and this signal is output from the output circuit 3 18 and the detector 3 2 6 Notify the detection object 2 invasion to the outside.

 In this way, data is held by alternately switching the two detection signals II and I2 obtained by the passive method, sampling and holding each detection signal as a pair, and holding the data. Since the processing is performed by the signal processing circuit including the light receiving circuit, the scale of the signal processing circuit can be reduced, and the same operation and effect as those of the third embodiment can be obtained. In addition, the clock signal that performs switching of the detection signal is pulse-time modulated, synchronized with the signal, and processed to remove physical and electrical noise that is different from the periodic detection target. Therefore, a high SZN detection signal can be obtained. As a result, a smaller change in the detected current can be handled, so that the presence / absence of an object can be detected more accurately.

 (3 g) Example 3 g

FIG. 60 is a block diagram of the detector according to Example 3g, and FIGS. 61 a to 61 i are timing charts of this detector. The detector 330 is different from the detector 310 shown in FIG. 51 in that the timing of power supply to the signal processing circuit is controlled. Switch SW 3 is added. This switch SW3 is switched by a signal AG synchronized with the signals SG1 and SG2 supplied from the oscillation circuit 307, respectively. As a result, power is supplied only for the time necessary for signal processing for each of the signals SG1 and SG2, as shown in the time chart of FIG.

 As described above, the two systems of the detection signals 11 and 12 obtained by the passive method are alternately switched, and each of the detection signals is sampled and held as a pair. Since the processing is performed by the signal processing circuit including the light receiving circuit of the system, the scale of the signal processing circuit can be reduced, and the same operation and effect as those of the third embodiment can be obtained. In addition, power supply to each signal processing circuit is intermittently performed for the time required for signal processing, so that current consumption can be further reduced. In addition, since power is supplied according to the respective oscillation pulse signals of the signal SG1 and the signal SG2, the signal SG1 and the signal SG2 are controlled so that the signals of the voltage V1 and the voltage V2 do not interfere with each other. Even if the pulse interval is wide, it is possible to respond to an excessive input detection signal while maintaining the effect of reducing current consumption.

 (3 h), Example 3 h

Figures 62a to 62j show time charts of the operation of the detector according to Example 3h. The detector according to the present embodiment has the same configuration as the detector 330 according to the third embodiment. Switch SW3 uses the signals SG1 and SG2 supplied from the oscillating circuit as the ground signals, and is switched by the signal AG synchronized with this pair of signals. Thus, as shown in the time charts of FIGS. 62a to 62j, the power is supplied only for the time required for the signal SG1 and the signal SG2 at the same time for the signal processing related thereto.

 In this way, the data is held by alternately switching the two detection signals 11 and 12 obtained by the passive method and sampling and holding each detection signal as a pair. Since the signal is processed by the signal processing circuit including the light receiving circuit, the size of the signal processing circuit can be reduced, and the same operation and effect as those of the first embodiment can be obtained. In addition, power is supplied to each signal processing circuit only for the time required for signal processing of signal SG1 and signal SG2.If the pulse period of signal SG1 and signal SG2 is lengthened, power Since the supply time is shorter, it is possible to further reduce the current consumption.

 (3i) Example 3i

FIG. 63 is a block diagram of a detector 331 according to the embodiment 3i, and FIG. 64 is a time chart of this detector. The detector 331 performs the switching of the switch SW3 by the signals SG1 and SG2 supplied from the oscillation circuit 307 in the detector 3330 shown in FIG. Things. In this way, supply of power to each circuit and switching of the detection signal are performed. By using the same signal, the number of oscillation pulse signals can be reduced, and the configuration of the oscillation circuit 7 can be simplified, so that the circuit scale and current consumption can be further reduced.

 (3j) Example 3j

 FIG. 65 is a block diagram of the detector according to the present embodiment, and FIG.

~ Figure 66 j is the time chart of this detector. This detector 3332 is the same as the detector 301 shown in FIG. 51 except that a switch 34 is added between PD1 and PD2 and the light receiving circuit 308. A bandpass filter 319 is added between the amplifier circuit 309 and the SZH circuit 310. The switch SW4 is switched by a signal FG synchronized with the signals SG1 and SG2.

Each PD outputs a detection current in accordance with the light input power to the PD, PD 1 outputs a current II, and PD 2 outputs a current I 2. The detection currents II and 12 pass through the switches SW 1 and SW 2, respectively, pass through the switch SW 4, and are sent to the light receiving circuit 308. Since the pulse width of the signal FG that controls the switch SW30 is smaller than the pulse widths of the signals SG1 and SG2, the detection currents I1 and I2 are chopped and converted to high-frequency signals. It is possible to do. The detection currents II and I2 are converted into voltages by the light receiving circuit 308 and amplified by the amplifier circuit 309 to become voltages V1 and V2. By passing these voltages VI and V2 through the bandpass filter 319, the power supply generated when a fluorescent lamp is used as the light source is reduced. Noise such as frequency noise and high-frequency noise generated by the light receiving elements PD1, PD2 and the light-receiving circuit 308 can be eliminated. The noise-removed signals F 1 and F 2 are sampled by the SZH circuit 310 at the sampling and holding signal SH of the oscillation circuit 307, and then digitalized by the AZD conversion circuit 311. And output D 1 and D 2 respectively. These outputs Dl and D2 are subjected to a difference operation (D1-D2) in the operation unit 312 to obtain an operation result D. This value D is compared with the threshold value VT by the comparison circuit 316. When the value exceeds VT, an ON signal is output. If this 0 N signal becomes three or more consecutively, a binary ON signal is obtained from the integrating circuit 3 17, and this signal is output from the output circuit 3 18, and the detector 3 3 2 Inform the detection object 15 of the intrusion.

As described above, according to the detector 33 of the present embodiment, the two detection signals I 1 and 12 obtained by the passive method are switched alternately, and each detection signal is sampled and held as a pair. As a result, since the data is held and processed by the signal processing circuit including one light receiving circuit, the scale of the signal processing circuit can be reduced, and the same operational effects as those of the above-described embodiment 3a can be obtained. Obtainable. In addition, by chopping the detection signal, converting it to a high-frequency signal, and removing the noise with a filter 319, optical and electrical noise can be removed. A high S / N detection signal can be obtained. This makes it possible to handle smaller changes in the detection signal. As a result, the presence or absence of an object can be detected more accurately.

 (3k) Example 3k

 FIG. 67 is a block diagram of the detector 33 33 according to the embodiment 3k, and FIGS. 68a to 68j are schematic diagrams of the detector. The detector 333 according to the present embodiment converts the detection signal into a high-frequency signal when the switches SW1 and SW2 are switched. That is, the current I from P D 1

The currents 12 from I and PD 2 are alternately switched by switches SW 1 and SW 2 with the clocks of signals SGI and SG 2. These detection currents I 1 and I 2 include power supply low-frequency noise generated when a fluorescent lamp is used as a light source. In order to remove them, conversion to high-frequency signals that are separated from low-frequency noise when switching switches SW1 and SW32 are also performed, and then pass through a band-pass filter 319.

 Thus, the two detection signals obtained by the passive method

Switching between II and 12 alternately, sample-holding each detection signal as a pair, and holding the data, which is processed by a signal processing circuit including a single light-receiving circuit. The circuit scale can be reduced.

The same operation and effect as 3a can be obtained. In addition, by performing time regulation and waveform shaping at the same time, a dedicated switching gate for waveform shaping and an oscillating pulse signal given to it can be deleted. Times The road scale can be reduced.

 (31) Example 31

 FIG. 69 is a block diagram of a detector 334 according to the embodiment 31. This detector 334 is different from the detector 333 shown in FIG. 67 in that the oscillation circuit 307 is configured to output an oscillation pulse signal having a plurality of frequencies. By changing the pass frequency of the filter 319 in the same way, it is possible to cope with a change in the noise situation caused by a change in the use environment.

 The light incident on PD 1 and PD 2 is converted from light to current here, and the detection current I 1 from PD 1 and the detection current I 2 from PD 2 are converted into switches SW 1 and SW 2 Light receiving circuit 3 intermittently

Sent to 08. The switches SW1 and SW2 are alternately switched by the oscillation pulse signals SG1 and SG2 supplied from the oscillation circuit 307. 1, current I 1, passing through SW 2

The timing of 132 is asynchronous and time division. Current I 1,

I2 is converted into a voltage by the light receiving circuit 308 and then amplified by the amplifying circuit 309 to become voltages V1 and V2. The voltages VI and V 2 are passed through a band-pass filter 319 to remove low-frequency noise and become voltages F 1 and F 2. The voltages F 1 and F 2 are sampled by the SZH circuit 310 at the timing of the sample and hold signal SH. The sampled detection signal is converted to a digital signal by the AZD conversion circuit 311 and then converted to a digital signal. The outputs are Dl and D2, respectively. These outputs Dl and D2 are subjected to a difference operation (D1-D2) in the operation unit 312 to obtain an operation result D. The calculation result D is compared with the threshold value VT by the comparison circuit 316. When the threshold value VT is exceeded, a 0 N signal is output. If the number of consecutive 0 N signals becomes three or more, a binarized ON signal is obtained from the integrating circuit 3 17, and the detection circuit 3 3 4 is output to the outside of the detector 3 3 4 from the output circuit 3 18. Signal an intrusion.

 When the use environment in which the detector 334 is placed changes, the frequency of noise such as a power supply low-frequency noise included in the detection signal output from the PD also changes. Therefore, in order to accurately detect the presence or absence of an object, the oscillation frequency of the oscillation pulse signals SG 1 and SG 2 output from the oscillation circuit 307 is changed according to the change in the use environment, and It is necessary to change the pass frequency of the filter 319 so as to take out only the detection signal in conjunction with it. The detector 3 3 4 according to the present embodiment is provided with a switch SW 5 for externally changing the frequency of the signals SG 1 and SG 2 in order to avoid the noise frequency of the use environment. Depending on the position of the switch SW5, the low cut-off frequency 1 (27ΓR s C s) of the filter 319 is changed to the oscillation frequency 1Z (27ΓR Co) of the oscillation pulse signals SG1, SG2. It can be changed in conjunction with it.

In this way, the two systems of detection signals (11, 12) obtained by the passive method are alternately switched, and each detection signal is sampled and held as a base to retain data. Is performed, and processing is performed by a signal processing circuit including a single light receiving circuit. Therefore, the scale of the signal processing circuit can be reduced, and the same operation and effect as those of the third embodiment can be obtained. Furthermore, the oscillation frequency of the oscillating pulse signals SG 1 and SG 2 of the received light signal is changed according to the noise situation in the use environment, and in conjunction with this, the pass frequency of the filter 19 that extracts only that signal is changed. This makes it possible to remove physical quantity noise and electrical noise that are different from the periodic detection target, so that a high S / N detection signal can be obtained and smaller signals can be handled.

 (3 m) Example 3 m

 FIG. 70 is a block diagram of the detector 335 according to the third embodiment. The detector 335 according to the present embodiment has a configuration in which the gain of the amplifier circuit 309 can be changed in accordance with a change in the oscillation frequency of the oscillation pulses SG 1 and SG 2.

 The light incident on PD 1 and PD 2 undergoes photo-current conversion, and the detection current I 1 from PD 1 and the detection current I 2 from PD 2 are converted into switches SW 1 and SW 2 Light receiving circuit 3 intermittently

Sent to 08. The switches SW1 and SW2 are alternately switched by the oscillation pulse signals SG1 and SG2 supplied from the oscillation circuit 307. The current I 1, passing through SW 1 and SW 2

The evening of 1 and 2 is asynchronous and time division. After the currents I 1 and I 2 are converted into voltages by the photodetector circuit 108, It is amplified by 9 and becomes voltages V 1 and V 2. The voltages V 1 and V 2 are passed through a band-pass filter 319 to remove low-frequency noise and become voltages F 1 and F 2. The voltages F 1 and F 2 are sampled by the S / H circuit 310 at the timing of the sample hold signal SH. The sampled detection signal is converted into a digital signal by the AZD conversion circuit 311 and then output as Dl and D2, respectively. These outputs Dl and D2 are subjected to a difference operation (D1-D2) in the operation unit 312 to obtain the operation result D. The calculation result D is compared with the threshold value VT by the comparison circuit 316, and when it exceeds VT, an ON signal is output. If the number of ON signals becomes three or more in succession, a binarized ON signal is obtained from the integrating circuit 3 17, and the detection circuit 3 3 5 Signal an intrusion.

When the use environment where the detector 335 is placed changes, the frequency of noise such as power supply low-frequency noise included in the detection signals output from PD1 and PD2 also changes. Therefore, in order to accurately detect the presence or absence of an object, the oscillating frequency of the oscillating pulse signals SG 1 and SG 2 output from the oscillating circuit 307 is changed according to the change of the use environment, and furthermore, It is necessary to change the gain of the amplifier circuit 309 so that only the detection signal is taken out in conjunction with it.p The detector 335 according to this embodiment is designed to avoid noise frequencies in the operating environment. The switch SW5 for changing the frequency of the signals SG1 and SG2 from the outside is added, and the position of the switch SW5 allows the gain of the amplifying circuit 309 to be changed. R f ZRs can be changed in conjunction with the oscillation frequency 1 / (2TTROCO) of the oscillation pulse signals SG1, SG2.

 In this way, data is retained by alternately switching the two detection signals II and I2 obtained by the passive method and sampling and holding each detection signal as a pair. Since the processing is performed by the signal processing circuit including the light receiving circuit, the scale of the signal processing circuit can be reduced, and the same operation and effect as those of the above-described embodiment 3a can be obtained. Furthermore, it is necessary to change the oscillation frequency of the oscillation pulse signals SG 1 and SG 2 of the light reception signal according to the noise situation of the use environment, and to change the gain of the amplification circuit 309 in conjunction with it. Therefore, it is possible to more accurately remove physical quantity noise and electrical noise that are different from those to be detected periodically, so that a high SZN detection signal can be obtained and a smaller signal can be handled.

 (3 n) Example 3 n

FIG. 71 is a diagram showing a configuration of an infrared sensor according to Example 3m. The infrared sensor 340 according to this embodiment is the same as the detector shown in the above embodiments 3a to 3m, except that an infrared detecting element 342 (such as a thermopile) is provided instead of the PD. . As a result, the circuit size and simplification of the infrared sensor 342 for detecting the intrusion of a person 343 into the detection area can be reduced, and the size of the sensor 340 can be reduced. Can be reduced. (3o) Example 3o

 FIG. 72 is a diagram illustrating the configuration of the temperature sensor according to the third embodiment. The temperature sensor 344 according to this embodiment is the same as the detector shown in the above-described 3a or 3 m embodiment, except that a temperature detection element 345 is provided instead of the PD. This makes it possible to reduce and simplify the circuit scale of the temperature sensor 344 used for temperature control and the like in a device such as a molding machine.

 (3p) Example 3p

 FIGS. 73a and 73b are diagrams showing a configuration of a pressure sensor according to the present embodiment and an equivalent circuit thereof. The pressure sensor 346 according to the present embodiment is the same as the detector shown in the above-described embodiments 3a to 3m, except that a pressure detecting element 347 is provided instead of the PD. This makes it possible to reduce and simplify the circuit scale of the pressure sensor 346 that controls the pressure section of a device such as a molding machine.

 (3 q) Example 3 q

 FIG. 74 is a diagram showing the configuration of the gas sensor according to the third embodiment q. The gas sensor 348 according to this embodiment is the same as the detector shown in the above-described 3a or 3 m embodiment, except that a gas detection element 349 is provided instead of the PD. This makes it possible to reduce and simplify the circuit scale of the gas sensor 348 for controlling mixed gas and detecting gas leakage and the like.

 (4) Fourth embodiment

Next, a fourth embodiment will be described. In the fourth embodiment A light-dark pattern is provided on the background 14 of the first embodiment.

 (4a) Example 4a

 FIG. 75 shows the basic configuration of the object detector 401 according to the fourth embodiment. The optical system portion includes a reflector 414, a light receiving lens 403, and a photodetector 418. Natural scattered light from the period

 (Lighting equipment, sunlight, etc.) are reflected by the reflector 4 14 and the detection object 15. The reflected light enters the light receiving lens 403. Further, the light is condensed on the light detecting element 418 by the light receiving lens 403. In the present embodiment, the photodetecting element 418 uses two divided PDaPDb. Each PD outputs a current proportional to the amount of light incident on the light receiving surface. When PSD is used as another photodetector, a current corresponding to the position of the center of gravity of the light intensity distribution in the light receiving surface is output. When a two-segment PD is used, the light receiving field of view is two, light receiving fields a and b, as shown in Fig. 75, and the contrast pattern of the reflector is correspondingly two patterns. Here, a white and black pattern is used for simplification.

The output currents Ia and Ib of the two divided PDa and PDb are periodically switched by a pulse signal SG by analog switches 412a and 412b input to the PD output line. The DC signal is converted to a pulse signal. The output currents Ia, I, and b are voltage-converted by the I / V converters 421 and 422, and Va also becomes Vb. Next, Vb−Va is obtained by the differential amplifier circuit 409, and this Vb−Va is a light amount difference signal between the light receiving fields b and a. Figures 76a to 76e show the relationship between the position of the detected object, the distribution of the received light amount on PDa and PDb, and the light amount difference signal Vb-Va. In the state without the detection object 15, the distribution of received light on PD a and PD b is as shown in Figure 76a, and the received light of PD a corresponds to the contrast pattern of the reflector 4 14. It is small and the amount of light received by PD b is large. The output current from the PD is I b> I a, and the output (light intensity difference signal) V b— from the differential amplifier circuit 409 switched by the analog switches 412 a and 412 b V a is as shown in FIG. If the detection object enters the light receiving field of view without this detection object 15, the received light distribution and light intensity difference signal on the PD are changed from Fig. 76 b to Fig. 76 c-Fig. 76 d → It changes to Figure 76 e.

 In the figure, w indicates the range occupied by the detected object. Figure 76a shows the case where there is no sensing object 15; Figure 76b shows the case where sensing object 15 has begun to obstruct the light receiving field of view a; Fig. 76 d shows the case where the detection object 15 has begun to block the light-receiving field b, and Fig. 76 e shows the case where the detection object 15 has completely blocked the light-receiving field b. Is shown.

In order to see the change in the light amount difference signal due to the presence or absence of the detection object 15, the sensitivity of the detector is adjusted as follows. Vb—Va with sensing object 15 is both larger and smaller than Vb—Va without sensing object 15 due to the reflectance of sensing object 15 There is. for that reason, The threshold value has two levels, V thl and V th2. The sensitivity adjustment circuit 4 1 1 is set so that the peak level V 0 of V b -V a without the detection object 15 comes to the center of the threshold values V thl and V th2. The sensitivity can be set by a variable resistor, or by a AZD conversion of the light intensity difference signal Vb-Va and then by a microcomputer. Also, the sensitivity setting may be performed inside or outside the detector 401.

 The light amount difference signal Vb—Va is compared with the threshold value set by the sensitivity adjustment circuit 4 1 1 by the comparison circuit 4 10, and the ON / OFF of the output is determined by the determination circuit 4 1 2. The result of the determination is output from 13.

Figure 77 shows the internal configuration of the comparison circuit 410 and the discrimination circuit 4122, and Figure 78a to Figure 78p show the time chart of its operation. When the differential amplified signal exceeds V th 1, the output of C 0 M 1 goes to H level, and when it falls below V th 1, it goes to L level. Similarly, when the voltage exceeds V th 2, the output of C 0 M 2 becomes H level. The discriminating circuit 412 first synchronizes the output of C0M1,2 with the switching period by AND1,2 gate (referred to as gate signal GATE). Next, at DFF 1 and 2, the output of C0M1 and 2 at the rising edge of the clock signal (falling edge of the SG signal) is output (see the timing charts in Figs. 78a to 78p). Become) . In addition, the differentially amplified signal Vb—Va is applied to the output of DFF 1 and 2 by the ENOR gate, and the threshold value Vth1, Vth The logic configuration is H level if both are above or below both, and L level if between V thl and V th 2. The next DFFs 3 to 5 are three-stage shift registers, which take the AND of the outputs of DFFs 3 to 5 and the inverted output, and use that output as the RSFF set signal and reset signal, respectively. RSFF is not set unless the EN0R output is at the H level for at least three periods of the SG signal. Similarly, the EN 0 R output is not reset unless the SG signal is at the L level for at least three cycles. Then, this RSFF output is sent to the output circuit and becomes the sensor output. In other words, if the differential amplified signal Vb—Va exceeds or falls below both Vth1 and Vth2 for at least three cycles of the SG signal, the sensor output is 0 N, and Vb—Va is the SG signal. Is between V th1 and V th2 for more than 3 cycles, the sensor output becomes 0FF.

 In the present embodiment, the reflection plate 14 and the detection object 15 are discriminated using the light amount difference signal of the two light receiving fields, but the divided value of the light amount of the two light receiving fields or the sum of the light amount difference and the light amount sum is obtained. It is also possible to determine using values.

 (4b) Example 4b

In Example 4b, the reflector was a black-and-white pattern, but if the object to be detected had a contrast, the reflector had no contrast. The difference between the object and the detected object is more likely to occur when the object has the reflectance or the reflection directivity. In addition, it is easier to discriminate if the reflectance is large. For example, automatic When detecting the passage of a vehicle body on a car production line, the detection object 15 is a metal surface, that is, a regular reflection surface without contrast. Therefore, the reflection plate 14 is a diffuse reflection surface with contrast (for example, blank paper). And black paper). In addition, when detecting the passage of a cardboard box on a transport line of a packaged article, since the detection object 15 is a diffuse reflection surface, the reflection plate is preferably a regular reflection surface (for example, a mirror).

 In some cases, the number of reflective surfaces is larger than the light receiving field. Fig. 79 shows one configuration. As shown in FIG. 79, there is one light-receiving field for the four divided reflecting surfaces. The received light amount changes as shown in FIG. 80 according to the position of the detection object 15. If the threshold is set to the level of a or b in FIG. 80, it can be determined that the detection object 15 is located in the area of ① or ③ on the reflection plate 14. It is assumed that the reflectances of the reflectors ② and と and the detection object are the same.

 (4c) Example 4c

Figure 81 shows a detector 450 of an object detection device that uses a battery as the power supply and supplies power intermittently. Since batteries 416 are used as the power supply, no work is required for wiring the power supply when installing the detector, and the installation location is not restricted. In addition, the power supply to the signal processing units such as the IZV conversion circuit 421 and the differential amplifier circuit 409 is intermittently supplied by the clock of the oscillation circuit 414, further reducing power consumption. Battery life can be prolonged. Fig. 82 shows a detector powered by the solar cell 4 17 to the storage battery 4 16. No external power supply is required by the solar cell 417, so maintenance after installation is not required.

 Fig. 83 shows a detector 450 that is supplied to the storage battery 4 16 by the hydroelectric power 4 32. As with detectors using solar cells, maintenance after installation is not required.

 (4d) Example 4d

In the case of the conventional regression reflection type photoelectric sensor, it is necessary to adjust the position of the sensor and the reflector, but the same applies to the present detector. Figure 84 shows the adjustment points. There are two adjustment points around the X-axis and Y-axis in the figure. When the distance between the reflector 14 and the detector 450 is short, it is possible to adjust the position visually, but when the distance is long, the visual adjustment becomes difficult. Therefore, as shown in Fig. 85, the detector 4 51 has a built-in light emitting LED 4 42, and the position of the detector 4 5 1 and the reflector 4 14 4 is adjusted using the light beam. There is a way to do it. FIG. 85 is a diagram showing a configuration in which the optical axis of the light receiving element and the optical axis of the light-emitting LED 442 are made coaxial by using a die mirror 441. The die mirror has the property of reflecting only the light in the wavelength range of the LED for light emission. The light beam emitted from the light-emitting LED 442 is reflected by the dichroic mirror 441, enters the light-receiving lens 403, and is emitted to the reflector 414. When adjusting the position, look at the projected beam reflected on the reflector 4 1 4 Adjust the position of the detector 4 15 from this.

 As another position adjustment method, there is a method using a reflector 414 and a four-divided PD 418a shown in FIGS. 86a and 86b. The circle at the center of the reflector 4 14 forms an image as shown by the dotted line in FIG. 80 b on the four-divided PD 418 a by the light receiving lens 40 3.

 Using the output II, 12, 13, and 14 differential outputs 13-II and 14-1-2 from the 4-split PD 4 18a, the center circle of the reflector 41 and the 4-split PD 4 An output corresponding to the displacement of the center of 18a is obtained. When the center circle of the reflector 4 1 4 and the center of the 4-split PD 4 18 a coincide with each other, 1 3 — 1 1 = 0, 1 4 1 I 2 = 0. For example, in FIG. If the center circle of the reflector and the center of the four-divided PD 4 18a are displaced as described above, I 3 1 1 1 = 0 and 1 4 1 1 2 are 0. 1 3 — 1 1, 1 4 1 By looking at the output of I 2, the direction of deviation between the center of the reflector 4 14 and the center of the 4-split PD 4 18 a can be determined, and it is provided on the detector 4 51 during position adjustment. If the direction is indicated on a display or the like, the adjustment can be simplified.

 (4 e) Example 4 e

Since the photodetector is a surface rather than a point, the light receiving field of view increases as the distance increases. Therefore, when the reflector 414 is placed at a long distance, the light receiving field becomes larger than the reflector 414, and the amount of light in the light receiving field may change due to an object outside the reflector 414. In this case, even though there is no detection object between the detector 45 1 and the reflection plate 41, the amount of light in the light receiving field of view changes and it may be determined that there is a detection object. That Therefore, as shown in FIG. 87, an aperture 443 is provided between the photodetector element 418 and the light receiving lens 403 to limit the light receiving field. In other words, there is a method in which the light-receiving field is contained within the reflector.

 (4 f) Example 4 f

 A parking lot system using the detector will be described. Figure

Figure 8 shows the layout of the detectors, and Figure 89 shows the system configuration. Indoor parking lots such as buildings can be considered as parking lots, and detectors 45 2 are installed on the ceiling of each parking lot. There is only the mark 447, for example, the number of the parking lot, in the field of view of the detector 452 when there is no car. On the other hand, if there is a car 4446, the reflected light from the car body is received by the detector 452, and the distance between the light-receiving field when there is no car (only with a mark) and when there is a car The detector 452 outputs whether or not there is a car in the parking lot by comparing the light quantity difference. In addition, the output from the detectors 45 2 installed at each parking lot is processed by the processing unit 4 44 4, and the parking lot is displayed by displaying the empty parking lot at the entrance on the display display 44 5. Parking lot users can stop the car smoothly.

 (4 g) Example 4 g

A vehicle detection system using the detector will be described. Figure 89 shows the system configuration diagram. As with the conventional sensitive traffic lights, the signal control unit 449 switches the signal from red to blue if there is an output from the detector 452 that there is a car. Mark 4 4 7 is provided on the road below detector 4 5 2 It is used as a reflector to determine the presence or absence of a vehicle that stops under the detector 452.

 (4 h) Example 4 h

 The axle number measurement system using the detector will be described. Figure 91 shows the system configuration diagram. This axle number measurement system is used in the vehicle type discrimination system used at unmanned toll booths on expressways. The detector 453 is arranged so that the car passes between the detector 453 and the reflector 414. When the car passes, the output of detector 453 turns ON. Based on the output from the detector 453, the axle force is counted at the axle number force point part 461, and the discriminator part 462 is used to determine the vehicle type using the axle number output. Is performed.

 (4i) Example 4i

A passgate system using this detector will be described. Figure 92 shows the system configuration. Figure 93 shows the detector arrangement. The passgate system of the automatic ticket gate at the station is a system that closes the exit door when a ticket that cannot be passed is entered, confirms that there are no more people in the passgate 463, and then opens the door again. I have. This sensor is used to confirm that no one is in passgate 463. When a person passes between the reflector 41 and the detector 45 54, it is determined whether the passer is in or out of the passgate 463 by judging the direction of passage. The output is processed by the people counting section 464 to determine the number of people in the passgate 463. Count. The processing unit 465 determines whether the number of people in the passgate is 0 or not. If it is 0, an instruction to open the door is output to the controller 466, and the door is opened.

 (4 j) Example 4 j

 An entry / exit management system using this detector is described. Figure 94 shows the system configuration. Detector 455 is installed on the ceiling of the entrance. A reflector (for example, a mark painted on the floor) 4 14 a is placed underneath. When a person passes between the detector 4 5 5 and the reflecting plate 4 14 a, it is possible to determine whether the person passing through the room exits or enters the room. It is possible to count the number.

 (4 k) Example 4 k

 A positioning device using the present detector will be described. Figure 95 shows the configuration. When the object 15 passes between the detector 4 56 and the reflecting plate 4 14, the light amount difference signal between the light receiving fields changes according to the amount of blocking the reflecting plate 4 14. The change amount is processed in the detector 456 to output an analog signal as shown in FIG. Using the output and the data set by the position setting section 474, it is determined whether or not the detected object 15 is at the set position. When it is at the set position, the position of the detection object 15 is determined by controlling the motor 471 which sends out the detection object 15 using the processing unit 473.

 (4 m) Example 4 m

Refer to Fig.97 for the length measuring device using this detector. Will be explained. In this embodiment, a car is used as the detection object 15, but it is naturally possible to detect other objects than the car. A linear image sensor using a PD array can be considered as the photodetector of the detector 457. A linear output according to the length is obtained. Further, instead of using a linear image sensor, the reflecting plate 4 14 may be constituted by a large number of reflecting surfaces. If the vehicle is a detected object as in this embodiment, the length W can be measured to be used as data for vehicle type determination or to determine whether or not the vehicle width can be parked in a parking lot. it can.

 (4 n) Example 4 n

 A monitoring system using this detector will be described with reference to FIG. This system detects the movement of an exhibit, such as an expensive artwork, that is, an almost stationary object. If the light amount difference in the light receiving field changes even a little, the output of detector 457 turns ON. The movement of the exhibit 472 is detected, and the security company 474 is notified of the abnormality of the exhibit 472 through the security monitoring system 473.

 (5) Fifth embodiment

 The detector in the fifth embodiment is basically the same as that in the fourth embodiment. The only difference is that the light portion of the light-dark pattern of the reflector 4 14 is used as the light-emitting body.

Referring to FIG. 99, in the fifth embodiment, a reflector 414 includes a light source 414a and a reference plane 414b. With this configuration Therefore, the passage of the detection object 15 can be detected stably even at night.

 Since the detector 450 is the same as that of the fourth embodiment, the light source 414 e does not need to have directivity, and may be, for example, a general lighting device. Further, since it is not necessary to have directivity, as shown in FIG. 100, an area sensor that can easily detect a plurality of areas with one light source can be configured.

 Furthermore, as shown in Fig. 101, the emergency light 511 is used as a light source and can be used for human body detection in case of fire. Since the detector 450 can be realized with extremely low power consumption, it can be very easily installed in an existing building by combining battery driving and wireless signal transmission. In addition, there is a merit that can be used as a failure detector that detects an emergency light bulb burnout in normal times.

 FIG. 102—FIG. 104 is a diagram showing an example of use of an area sensor using the detector 450 of the present embodiment. An area sensor having no mutual interference can be easily realized. According to this method, it is possible to detect not only the presence or absence of a detected object but also the moving direction of the detected object. In a place where there is always illumination, a similar effect can be obtained by arranging a contrast pattern instead of the light source at a position facing the light receiver.

 (6), sixth embodiment

In the sixth embodiment, an auxiliary light is added to the first embodiment. Hereinafter, a specific example of the sixth embodiment will be described with reference to the drawings. (6a) Example 6a

 FIG. 105 shows a configuration of the detector 600 according to the embodiment 6a, and FIGS. 106a to 1061 are time charts of the operation. This detector 600 is normally detected by receiving the natural scattered light (for example, lighting equipment and sunlight) reflected from the background object 14 and the detection object 15 at the place where the detector 600 is placed. A passive type detector 600 that performs light detection. The light receiving section 600 is composed of a light receiving lens 602 and a two-part photodiode 603 disposed behind the light receiving lens 602. The first and second light-receiving fields are configured for a contrasted background. Note that the detection object 15 shown in FIG. 105 has entered one of a plurality of light-receiving fields of the light-receiving unit 601. A detection operation is performed by emitting auxiliary light when the detection object 15 enters the light receiving field of view and receiving reflected light from the detection object 15.

When the presence or absence of the sensing object 15 is as shown in Fig. 106a and the ambient illuminance is as shown in Fig. 106b, the two light-to-current converted light signals by the two-part The signal is pulse-modulated by the pulse signal SG (FIG. 106c) for noise removal, and further amplified by the first and second amplifier circuits 606a and 606b. The amplified two light receiving signals (FIG. 106 d and 106 e) are subjected to differential operation by the differential amplifier 607, and the differential operation output (FIG. 106 ί) is output to the first, and second signals. Second comparison The circuits 608 a and 608 b compare the thresholds Vthl and Vth2 (Vth2 <Vthl) with two preset thresholds (Fig. 106 g, 106 h). The signal is processed by a signal processing unit 611 composed of a unit 609 and a judgment unit 610 (FIG. 106i106j). The outputs of the arithmetic unit 609 and the judging unit 610 are supplied to a light emitting trigger generating circuit 613. The auxiliary light projector 614 that emits the auxiliary light includes a light emitting element driving circuit 615 that receives an output of the light emitting trigger circuit 613 and operates and a light emitting element 616. The oscillating circuit 617 supplies the oscillating output to the calculating section 609, the judging section 610, and the light emitting element driving circuit 615, and outputs a signal SG. In the signal processing unit 611, the outputs of the first and second comparison circuits 608a and 608b (FIGS. 106g and 106h) are subjected to coincidence calculation by the calculation unit 609. Then, if the output of the arithmetic unit 609 is at the H level for three pulses of the pulse signal SG, the judgment unit 610 outputs an H level signal (FIG. 106 j), and The detection output is output from the output circuit 612 (Fig. 1061). If the outputs of the comparison circuits 608a and 608b match at the H level, the auxiliary light emitting section 614 starts emitting auxiliary light (FIG. 106k). When the determination unit 6110 outputs an H level signal, the emission of the assist light is stopped.

In this way, from the output circuit 612, if Vth2 <(differential operation output) and Vthl, the non-detection output (OFF: no detection object in the light-receiving field, ie, only the background object exists) Output, (differential output) Vth2 or V In case of thl (differential operation output), detection output (ON: detection object is present in the light receiving field) is output.

 Here, the auxiliary light emitting method will be described with reference to FIGS. 107A and 107B. In the light emitting element driving circuit 6 15 shown in FIG. 107a, when the light emitting trigger signal from the light emitting trigger circuit 613 is at the L level, the transistor TR 1 is in the 0 FF state. Therefore, the transistor TR 2 is in the 0FF state, and the light emitting element 6 16 is not turned on. When the light emission trigger signal from the light emission trigger circuit 6 13 is at the H level, the transistor TR 1 is turned on, so that the transistor TR 2 is pulse-driven by the light emission drive pulse of the oscillation circuit 6 17 Then, the light emitting elements 6 16 are turned on. Further, FIG. 107b is a logic circuit and a logic diagram of the light emission trigger circuit 613 for sending a light emission trigger signal to the light emission element drive circuit 615, and as shown in the logic diagram, the light emission is performed. The optical trigger circuit 613 outputs an H level light trigger signal when the operation unit output (Fig. 106i) is at H level, but the judgment unit output (Fig. 106j) is at L level. Is output.

In this way, when the detection object 15 enters the light receiving field of view, or when the output of the calculation unit 609 becomes H level due to noise, the emission of the auxiliary light is started, and the illuminance of the surface of the detection target object is started. And the output of the differential operation increases, so that reliable detection can be performed. Also, since the light emission time is extremely short, the amount of current consumption is extremely small, and it is possible to perform long-time driving even when driven by a battery. In addition, In this configuration, the passive type light receiving circuit that processes the light receiving signal for the auxiliary light projection and the light receiving circuit that processes the light receiving signal for the naturally scattered light are shared, so the number of components can be reduced and the cost is reduced. be able to.

 (6b) Example 6b

 FIG. 108 is a configuration diagram of a detector according to Embodiment 6b. The detector according to the present embodiment is configured to drive the detector of the above-described embodiment 6a with a battery, further detect the amount of battery by the detector, and a battery exhaustion detection circuit 618, And a display light driving circuit 619 for displaying the detection output of the light emitting element 619 of the above-described embodiment 6a. Shared with 6 1 5. That is, the indicator light drive circuit 6 19 is an oscillation circuit 6 1 that changes a light emission pulse in accordance with the output signal of the battery exhaustion detection circuit 6 18 and the light emission trigger of the light emission trigger circuit 6 13. Driven by 7 pulse signals. In addition, the light emission pulse for lighting this display and the light emission pulse for the auxiliary light emission are unsynchronized pulse signals.

 As described above, since the detector of this embodiment is provided with the dead battery detection circuit 618, it is possible to know in advance that the battery level is low, and it is possible to reduce malfunctions due to a drop in power supply voltage. In addition, since the auxiliary projector and indicator light are shared, the number of parts can be reduced and cost can be reduced.

(6c) Example 6c FIG. 109 is a configuration diagram of the detector according to the embodiment 6c, and FIG. 110 is a time chart of the operation. This detector is obtained by adding a threshold value correction circuit 620 and a light receiving circuit 621 for processing a light receiving signal of auxiliary light to the detector having the configuration shown in FIG. The light receiving circuit 621, which processes the light receiving signal of the auxiliary light, includes an addition circuit 62, a BP F.23 that passes only the light emission pulse frequency, and a third comparison circuit 608c. Hereinafter, the detection operation of this detector will be described with reference to the time charts of FIG. 11Oa to FIG. 11On by listing differences from the above-described embodiment 6a.

 (1) When the output of the operation unit (Fig. 110i) and the output of the judgment unit (Fig. 110j) do not match, the light emission trigger becomes H level and light is emitted (Fig. 110k). Detects by auxiliary light emission.

 (2) Even when the ambient illuminance decreases (Fig. 110b), Vth1 <(differential operation output) (Fig. 110ί).

609 becomes the Η level (Fig. 110i), and the auxiliary light is projected (Fig. 11Ok). However, when the presence of the detection object 15 is not detected by the detection using the auxiliary light, the light emission is stopped (FIG. 11Ok), and the detection output is not output (FIG. 1101). Then, the threshold value is automatically corrected by the threshold value correction circuit 62 so that the differential operation output falls between the threshold values (FIG. 110f).

As described above, whether the output of the arithmetic unit 609 has become the H level due to the entry of the detection object 15, noise, illuminance change, or The auxiliary light can be used to confirm whether the H level has been reached due to a change in the background object, and the detection accuracy can be improved. In addition, automatic detection of the threshold value enables stable detection without erroneous operation with respect to changes in illuminance and changes in background objects.

 Next, the algorithm of the auxiliary light emission in this embodiment will be described with reference to the time chart of FIG. As the detection method of this embodiment, the following methods (1) to (4) can be considered.

①When the object 15 enters the light-receiving field of view, the output of the calculation unit 609 is inverted, and when it becomes H level, light emission starts, and the object

When the presence of 15 is detected, the output of the judgment unit 61 is inverted and goes to H level, the detection output is output, and the light emission stops at the same time. Then, when the detection object 15 goes out of the light receiving field of view and the output of the arithmetic unit 609 is inverted and becomes L level, light emission starts, and the judgment unit 6100 determines that the presence of the detection object 15 is not detected. The output is inverted and goes to L level, non-detection output is output, and emission stops at the same time.

(2) When the detection object 15 enters the light-receiving field of view, the output of the calculation unit 609 goes to H level, the output is inverted by the judgment unit 6100 and the output is inverted. When the presence of 15 is detected, the detection output is output and the light emission stops at the same time. Then, the detection object 15 comes out of the light receiving field of view, the output of the calculating section 609 becomes L level, the output is inverted by the judging section 6100 and the output is inverted. And stop emitting light at the same time.

 (3) When the detection object 15 enters the light-receiving field of view, the output of the calculation unit 609 is inverted. When the H level is reached, light emission starts, and the presence of the detection object 15 is detected and the output of the judgment unit 6100 is inverted. Then, it becomes H level and the detection output is output. Thereafter, when the presence of the detected object 15 in the light-receiving field of view is no longer detected due to the detection operation by light emission, the output of the judgment unit 6100 is inverted to L level, and a non-detection output is output and Stop emitting light.

 に よ り When the detection object 15 enters the light-receiving field of view, the output of the calculation unit 609 becomes H level, the output is inverted by the judgment unit 610 and the output is inverted. When the presence of 15 is detected, a detection output is output. After that, when the presence of the detected object 15 in the light-receiving field of view is no longer detected due to the detection operation by light emission, the output of the arithmetic unit 609 becomes L level, the output is integrated by the judgment unit 610 and the output is inverted. Then, the L level is output, the non-detection output is output, and the emission stops at the same time.

 FIG. 11b is a diagram showing the features of the detection methods (1) to (4) described above. As shown in the figure, the detection methods ① to ④ have different characteristics in detection accuracy, response time, and current consumption. Therefore, it is possible to provide a detector that meets the purpose by utilizing each characteristic.

 (6 d) Example 6 d

FIG. 112 is a configuration diagram of a detector according to Embodiment 6d. This detector is designed to counter natural scattered light (eg lighting, sunlight). This is a passive type detector that performs detection by receiving emitted light, with the addition of an output prohibition circuit 624 that prohibits output in accordance with the detected illuminance. Is shown. In this embodiment, unlike the above embodiments, no auxiliary projector is provided.

 The detection operation of this detector will be described with reference to the time charts of FIGS. As shown in Fig. 11a, when the illuminance of the naturally scattered light decreases and the illuminance becomes undetectable with the passive type, the sum of the received light amounts of the two light receiving elements PD 1 and PD 2 is added. The output of the illuminance detector (Figure 13c), which is detected by the above, falls below the threshold value Vth3 of the comparison circuit 608c, and an H level signal is output from the output inhibition circuit 624 (Figure 11) 3 e :).

 The configuration of the output inhibition circuit 624 is as shown in FIG. When an L level signal is output from the comparison circuit 6 08 c, the output Q of the D flip-flop circuit 6 25 becomes L level. This L level signal is inverted by the inverter, and the H level signal is inverted. Become. The H level signal causes the output TR in the signal processing unit 6 1 1 to form a 0 FF circuit, and the transistor TR 1 becomes the ON state, so that the detection output is forcibly set to the L level and the output is OFF.

As described above, the detector of the present embodiment includes the output prohibition circuit 624 that prohibits the detection output in accordance with the change in the illuminance, so that the device controlled by the detector does not malfunction. In addition, If the output of this output prohibition circuit 6 24 is connected to the light emission trigger circuit 6 13 of the above-described embodiment 6a, it can be detected by the auxiliary light emission even under illuminance that cannot be detected by the passive method, and detection is continued be able to.

 (6 e) Example 6 e

 FIG. 115 is a configuration diagram of a detector according to Example 6e. Although the detector of Example 6d described above performs illuminance detection by detecting the total amount of light received by the light receiving element, the detector of this embodiment detects the illuminance by detecting the amount of light received by one light receiving element. It performs detection. Further, the detection operation is the same as that in the above-described embodiment 6d. This makes it possible to reduce the number of parts as compared with the detector according to Embodiment 6d described above.

 (6 f) Example 6 f

FIG. 116 is a configuration diagram of a detector according to Example 6f. This embodiment is obtained by adding a second light receiving section 604b to the configuration of the above-described embodiment 6d. This detector is provided with two light receiving sections, detects a detection object by a first light receiving section 604a, and performs illuminance detection by a second light receiving section 604b. Since the light receiving circuit of the light receiving section 604b can be designed with specifications limited to illuminance detection, illuminance can be detected with high accuracy. Also, if the light receiving field of illuminance detection is configured to look at a field of view different from that of the object to be detected, for example, the illumination, it is possible to reliably detect whether the illumination is on or off, and to perform accurate detection. (6 g) Example 6 g

 Fig. 117 is a circuit diagram showing the configuration near the output unit of the detector according to the embodiment 6g.This embodiment uses the detectors described in the above embodiments 6d to 6f to detect This is an addition of an output prohibition circuit at power reset that prohibits output from being output. To the OR circuit 626, a signal from the output prohibition circuit 624 that operates in response to a change in illuminance and a signal from the output prohibition circuit when the power is reset are input. Then, if one of these two signals is an H level signal, a prohibition signal is output. Since the transistor 627 is turned ON by this prohibition signal, the detection output from the signal processing unit 611 is not output. As described above, when the power supply voltage is lower than the voltage at which normal operation can be performed when the power is turned on, the output prohibition circuit operates when the power is reset, and the output of the detection output is prohibited. Malfunctions due to the above can be reduced, and a stable detection operation can be performed.

In addition, the above-described output prohibition circuit at power supply reset may be an output prohibition circuit due to a drop in power supply voltage (hereinafter referred to as an output prohibition circuit at voltage drop). Malfunctions due to the decrease can be reduced. In addition, the OR circuit 626 may be provided with three input terminals. These terminals are connected to three output inhibit circuits (output inhibit circuits that operate in response to changes in illuminance) and power reset. Output inhibit circuit, output inhibit circuit when voltage drops) A more reliable detection operation can be performed.

 Here, Fig. 118 shows a configuration in which both output prohibition circuits for output prohibition at power supply reset and output prohibition at voltage drop are shared, and the detection operation of this detection circuit is shown in the time chart of Fig. 119. It will be described with reference to FIG.

 First, the output prohibition circuit at power reset will be described. When the power is turned on by the switch SW, the voltage Vcc gradually rises due to the RC time constant, but when Vcc is low, the detection output is unstable because the detection is unstable. Output must be prohibited. When V cc is lower than the threshold value V thl (a voltage at which the detector can operate normally) of the comparator circuit 629, the comparator circuit 629 outputs an L level signal, and the L level signal is an The signal is inverted by the signal 631 and becomes an H level signal, and the transistor 627 is turned on via the OR circuit 626. Therefore, no detection output is output. Conversely, when V cc exceeds V thl, the output of the comparison circuit 629 becomes H level, and the disabled state is released.

Next, the output prohibition circuit when the voltage drops will be described. If the voltage Vcc decreases, the detection becomes unstable, and it is necessary to prohibit the output of the detection output. When V cc becomes lower than the detection voltage V th2 of the voltage detector 30, the voltage detector 63 0 outputs an L level signal, and this L level signal is inverted by the inverter — the H level signal Since the transistor 6 27 is turned on via the 0 R circuit 6 26, No detection output is output. Conversely, when V cc is higher than V th2, the voltage detector 630 outputs an H-level signal, and the detection output is output.

 With this configuration, devices that control the detector due to output prohibition do not malfunction. Also, by sharing the two prohibited circuits, the number of parts can be reduced and the cost can be reduced.

 (6 h) Example 6 h

 FIG. 120 shows Example 6h, and Example 6c! A warning indicator is provided to indicate that detection has become difficult by the output of the output prohibition circuit 624 as shown in Figs. If the output of the output prohibition circuit 624 is an H level signal, the transistor 633 is in the ON state, and the light emitting element 634 is turned on to indicate that the detection becomes difficult. On the other hand, if the output of the output inhibition circuit 624 is an L-level signal, the transistor 633 is in the 0 FF state, and the light emitting element 634 is not driven. In this way, the user can know that the ambient illuminance has decreased and no detection operation has been performed, and that the battery voltage has dropped and the battery cannot be used.

 (6i) Example 6i

FIGS. 12, 1, and 122 show the embodiment 6i and explain a method of prohibiting output. FIG. 12 1 is a diagram showing a configuration of a comparison unit 633, a calculation unit 609, and a determination unit 610 of the detector, and FIG. 122 is a configuration diagram of an output forced OFF circuit. Above The transistor TR61 is turned on by the output prohibition signal from the output prohibition circuit 624, and the detection signal is forcibly turned off. The four signals A, B, C, and D can be considered as OFF signals. 0 When the signal to be flipped is the detection output signal D, the output is quickly inhibited in response to the output inhibit signal. On the other hand, the method of 0FFing the signal of the output signal A of the differential amplifier, the Ex-NOR output signal B of the signal processing unit, and the input signal C to the AND gate of the shift register of the signal processing unit is differential. The closer to the amplifier, the more the output prohibition signal is delayed, but the detection output can be reliably prohibited.

 (6 j) Example 6 j

FIGS. 12 3 and 12 24 a to 12 4 d show the embodiment 6 j, in which a detector having an output inhibition circuit 6 24 is supplied to the detector according to the output inhibition output. A power supply cycle changer that changes the power supply pulse is added. Fig. 123 shows the configuration, and Figs. 124a to 124d show the time chart of the operation. The power supply cycle changer includes first and second oscillation circuits 635a and 635b having different oscillation cycles and a two-input multiplexer 636. This detector normally performs detection based on the pulse period oscillated from the first oscillation circuit 635a, and an output inhibition signal is output from the output inhibition circuit 624 due to a decrease in ambient illuminance, etc. In this case, the selection signal is input to the 2-input multiplexer 36, and the pulse cycle is switched from the first oscillation circuit 635a to the second oscillation circuit 635b with longer oscillation cycle. Change. Thereby, low current consumption can be achieved.

 (7) Seventh embodiment

 Next, a seventh embodiment will be described. In the seventh embodiment, the content of the signal processing in the first embodiment is specified.

 (7a) Example 7a

 A specific example of this embodiment will be described with reference to the drawings. Fig. 125 is a block diagram of the detection device 700 according to the embodiment 7a, and Figs. 126a to 126i are time charts of operations in the detection device. The detection device 700 detects an object or the like that was not in the initial state, and the object to be detected 1 is detected by natural scattered light such as illumination light or sunlight at the place where the detection device 700 is installed. It comprises a photodetector 701 for detecting the signal No. 5 and various processing circuits such as a differential amplifier circuit 706 for processing and outputting the detected light receiving signal.

The light detection section 701 is composed of a light receiving lens 703 that collects naturally scattered light reflected from the detection object 15 and the background object 1, and two photo diodes PD 1 and PD that convert light into current. 2 The processing circuit includes two amplifier circuits 704 and 705, a differential amplifier circuit 706, a high-pass filter HPF 707, a comparison circuit 708, an integration circuit 709, and an output circuit. It comprises a power circuit 7, 10 and an oscillation circuit 71. To perform the initial setting, the initial setting circuit 7 11, the change amount detection circuit (adjustment amount detector) 7 1 2 at the time of initial setting, and the discrimination level setting circuit (threshold value setting device) 7 1 and 3 are included. Light reflected by the detection object 15 and the background object 14 is condensed by the light-receiving lens 703, and the light passing through the lens 703 is divided into two light-receiving fields forming two light-receiving fields. The light is received by the photo diode PD1, PD2 (photodetector) and converted into light-current.

 These two light-to-current converted light receiving signals are converted into high-frequency signals by a switching pulse SG (FIG. 12B), and are amplified by the amplifier circuits 704 and 705, respectively (see FIG. 1). 26 c, 126 d). Here, when the detection object 15 enters one light receiving field of view (Fig. 12 26a), the outputs of both amplifier circuits show a change. These two amplified light receiving signals are subjected to differential operation by the differential operation circuit 706 (FIG. 12E). The low-frequency noise is removed from the differentially calculated light-receiving signal by the HPF 707 (see FIG. 126), and the comparison circuit 108 sets two thresholds V thl and V th 2 (V th 2 <V th 1). In order to prevent the output from becoming unstable due to the noise amount of the received light signal, the larger threshold V th1 is set to V th1−S at the output of the integrating circuit 709, The threshold V th2 is changed to V th 2 + y (β, r> 0), respectively. The comparison circuit 708 outputs an H level signal if the differential output is out of the discrimination range, and outputs an L level signal if the differential output is not out of the discrimination range (Fig. 126g).

Subsequently, the output signal of the comparison circuit 708 is sent to the integration circuit 709. The noise is further removed (Fig. 126h), and output by the output circuit 710. Specifically, as shown in Fig. 126 i, if V th 2 <(the differentially calculated light receiving signal) <V th 1, the non-detection output (OFF: no detected object is in the light receiving field) (Ie, the state where only the background object exists) is output to the outside of the sensor. In addition, when (differentially calculated light receiving signal) is less than V th2 or V th 1 <(differentially calculated light receiving signal), the detection output (ON: the detected object is within the light receiving field) Is output outside the sensor. In this way, the object can be detected based on the fluctuations of the two received light signals, so that O o

Next, the light receiving signal in the initial state (the state where there is no detected object) will be described. In the initial state, there is almost no contrast between the two light receiving fields, and there is some contrast, so that the signal component of the differential output of the differential arithmetic circuit 706 is a signal There are levels. In addition, the noise component included in the light reception signals received from the two light reception fields increases according to the amount of received light. When the two light receiving signals are subjected to differential operation, if there is no difference between the two light receiving signals (there is no contrast), the noise components of the two light receiving signals are almost equal and are removed, and the noise of the differential output is reduced. The component is almost zero. Conversely, if there is a difference (contrast) between the two received light signals, the noise component of the differential output will depend on the difference between the two received light signals, that is, the magnitude of the signal component of the differential output. growing. Therefore, the detection device needs to be initialized so that the detection signal is output properly regardless of the change in the signal component of the differential output in the initial state and the environment in which the detection device is used. The initial setting is a process to put the differential operation output in the initial state (the state where there is no sensing object) within the levels of the two thresholds Vth1, Vth2 (Vth2 <Vth1). is there. The target of the initial setting is the initial setting circuit 711, the change amount detection circuit 712 at the time of the initial setting, and the discrimination level setting circuit 713.

 The initial setting circuit 7 1 1 is a circuit that allows the differential operation output to fall within the levels of the two thresholds V thl and V th 2 when there is no sensing object. There is a way to change the threshold without changing the differential output.

 The change amount detection circuit 7 1 2 at the time of the initial setting is a circuit which detects how much the differential operation output has been changed at the time of the initial setting, or how much the threshold value has been changed, and the physical quantity thereof. The discrimination level setting circuit 713 is a circuit that sets a threshold value and a hysteresis width according to the physical quantity detected by the change amount detection circuit 712 at the time of initial setting. The method of changing the threshold value without changing the differential output at the time of initial setting only sets the hysteresis width.

In this way, it is possible to set the threshold and hysteresis width according to the amount of change at the time of initial setting (the signal component of the differential output in the initial state). The detection device malfunctions due to the usage environment Nothing. Further, the threshold value is set above and below the detection signal, and an output signal is output when the detection signal deviates from the level. Therefore, the direction in which the light-receiving output changes is not limited. Here, according to the detection device of the present embodiment, the object can be detected without selecting the contrast between the visual field and the background for detecting the detected object, and the sensitivity of the sensor is greatly improved.

 Hereinafter, the method of initial setting will be described with reference to FIGS. In FIG. 127 to FIG. 127 d, only the initial setting method is shown, and the threshold value and the hysteresis width setting method are not shown. They will be described in Figure 13 1 and thereafter. FIG. 127 illustrates the basic concept of the initial setting. As shown in this figure, the initial setting means that the output signal level Vsp of the differential amplification output is set to two thresholds Vthl, Vth2 (Vth2 <Vth1 ) Level.

 FIGS. 128a and 128b are a circuit diagram when the reference voltage of the differential amplifier circuit 706 is changed and a diagram showing the relationship between the reference voltage and two thresholds at that time. In this case, the output V s [= V ref-(R i / R s) v] of the amplifier circuit is changed by changing the reference voltage V ref (V ref —A e) to obtain the V s shown in FIG. 127. 0 changes to set Vsp within the threshold level. In this way, the dynamic range of the amplifier can be used effectively.

Figure 128c and 128d show changes in the amplification factor of the amplifier circuit 706. FIG. 9 is a circuit diagram in a case where the threshold voltage is changed, and a diagram showing a relationship between a reference voltage and two threshold values at that time. In this case, the output Vs is changed by changing the amplification factor (RfZRs) of the amplifier circuit 706, and Vsp is set within the threshold level. In this method, it can be used even in a high-light environment.

 FIGS. 12a and 12b are a circuit diagram in the case of attenuation of the received light signal and a diagram showing the relationship between the reference voltage and the two thresholds at that time. In this case, the output Vs is set within the threshold level by the output of the amplifier circuit being attenuated by (R a 1 / R a) times by the resistance voltage division. In this method, the cost is reduced because the configuration is simple.

 FIGS. 1229c and 1229d are a circuit diagram in the case where the DC offset value of the output of the amplifier circuit is changed, and a diagram showing the relationship between the reference voltage and the two threshold values at that time. In this case, by changing the DC offset of the output of the amplification circuit, V 0 shown in Fig. 127 is changed, and the output V s becomes V s = V ccx (RD 2 RD)-( R f / R s) X v, and sets the output V s within the threshold level. In this method, the same effect as in FIGS.

 (7b) Example 7b

 The embodiment shown in FIG. 130 is a teaching method in which the initial setting and the setting of the threshold value are automatically performed by a command from the outside of the detecting device.

In Fig. 130, the differential output of the received light Sample and hold by the sample and hold circuit 715, AZD conversion by the AZD conversion circuit 716, and comparison by the comparison circuit 108 with the discrimination range stored in the memory 122 by the initial setting. After passing through an integrating circuit 709 for noise removal, the output of is output to the outside of the sensor by an output circuit 710.

 The initial setting is that when the external switch SW1 that executes the execution command is set to 0 N, a plurality of light-receiving outputs are output from a plurality of memories 718 and 719 by the trigger signal of the initialization circuit 717. It is memorized. The stored light receiving signal is calculated by the arithmetic circuit 720 (for example, an average value, an intermediate value between the maximum value and the minimum value), and a discrimination range is set. The set value is stored in the memory 721, and the initial setting is performed. According to this method, initial settings can be made very easily.

Next, a specific circuit configuration of the above-described embodiment 7b will be described with reference to FIG. In FIG. 13 3, the initial setting circuit 71 1 is a reference voltage V 0 = V cc X (R 3 1 / R 3). The buffer output V 0 of the same circuit 71 1 is input to the absolute value circuit 73 1. The absolute value circuit 731 outputs the difference Vl = Vref + | Vref-VOi between the reference voltage value Vref and V0 of the amplifier. Then, the differential amplifier 722 performs a differential operation between V 1 and V ref, and outputs V 2 = V BE 1 + IV ref -V 0 I. Voltage V 2 is converted by the current source 1 into a current I l = (V _BE l + | V ref — V 0 I-V BE 2) / R 1 0 ^ | V ref-V 0 I / R 10. When the output of the detection device is 0 FF, hys is at the H level, and the transistor TR 3 is in the 0 FF state. Therefore, I0 = (R14 / R16) XIIV thl = Vref + R17xI0. Vth2 = Vref-R18XI0. When the output of the detector is ON, hys is at L level and transistor TR3 is ON. Therefore, I 0 ((R 1 3 // R 1 4) / R 1 6) XI 1 (where R 1 3 // R 1 4 represents the parallel connection resistance of R 1 3 and R 1 4). :), Vth1 = Vref + R17xI0, Vth2 = Vref-R18xI0. Therefore, by changing the resistance R31 of the initial setting circuit 711, the initial setting, the threshold value, and the hysteresis width can be changed in conjunction. With this configuration, optimal initial settings can be easily made.

 Regarding the operation of the absolute value circuit 731, when V 0 <V ref, the diode D 1 becomes 0 N, and the negative feedback loop passing through the diode D 1, the amplifier AMP 4, and the resistor R 5 The output is Vl = Vref + Vref-V0. When V 0 ≥ V r e i, the diode D 1 is turned off and the amplifiers A M P 3 and A M P 4 are separated, and the output becomes V l = V r e f — (V r e f-V 0).

Fig. 13 2 shows the discrimination level setting circuit 7 1 3 that changes only the hysteresis width according to the amount of change at the time of initial setting. FIG. The change amount V2 at the time of initial setting is converted to the current value I1 = (V2-VBE1) / R1 by the current sources 1 and 2. Also, the current value of the current source 2 is I 2 = (V 2 −V BE 2 −V BE 3) / R 6. When the output of the detector is OFF, hys is at H level and transistor TR1 is set to 0N. Therefore, the sum of the current I 1 of the current source 1 and the current I 2 of the current source 2 flows through the resistors R 4 and R 5, and V thl = V ref + R 4 x (1 1 + 1 2), V th 2 = V ref-R 5 x (1 1 + 1 2). When the output of the detector is ON, hys is at L level, transistor TR1 is OFF, and I1 = 0. Therefore, V thl = V ref + R 4 XI 2, V th 2 = V ref —R 5 xI 2. Therefore, the current value I 1 = (V 2-V BE 1) / R 1 of the current source changes according to the change amount V 2, so that only the hysteresis width changes according to the change amount at the initial setting. Is done. According to this configuration, when the differential operation output at the time of initial setting is small (where there is no background contrast), fine initial setting can be performed in accordance with the ambient illuminance, and detection accuracy can be improved.

FIG. 13 is a circuit diagram of a discrimination level setting circuit 7 13 in which only the threshold value is changed according to the amount of change at the time of initial setting. The change amount V2 at the time of the initial setting is converted into a current value I1 = (V2-VBE1) / R1 by the current sources 1 and 2. The current value of the current source 2 is I 2 = (V 2 -V BE 2 -V BE 3) ZR 6. When the output of the detector is OFF, hys is at H level and transistor TR1 is set to 0N. Therefore, the resistors R 4 and R 5 , The sum of the current I 1 of the current source 1 and the current I 2 of the current source 2 flows, and V thl = V ref + R 4 x (1 1 +1 2), V th 2 = V ref — R 5 x ( 1 1 + 1 2). When the output of the detector is ON, hys is at L level, transistor TR1 is OFF, and 1 2 = 0. Therefore, V thl = V ref + R 4 XI 1, and V th 2 = V ref —R 5 XI 1. Therefore, the current value I 1 = (V 2-V _BE 1) / R 1 of the current source changes according to the change amount V 2, and only the threshold value changes according to the change amount at the initial setting. Is done. According to this configuration, initial setting is easy when the differential operation output at the time of initial setting is large (where there is a background contrast). FIGS. 13A and 13B are modified examples of the change amount detection circuit 7 12 at the time of the initial setting described above, and are diagrams showing circuits suitable for detecting the change amount of the AC signal. 1334a is a part of the circuit diagram, and Fig.136b is its time chart. In the case where the initial setting unit described above attenuates the received light output or changes the DC offset, the present embodiment detects the magnitude of V 0 and outputs the detected signal to the absolute value circuit 7 3 1 in FIG. To detect the amount of change. Then, the threshold and the hysteresis width are set by the above-described discrimination level setting circuit 711 according to the amount of change. Regarding the detection of the magnitude of V0, when the control signal CTL of the transistor TR1 is at the H level, the diode D1 does not conduct and the potential between VS and VG becomes the same potential, and the transistor TR1 changes to the 0N state. Become. Therefore, capacitor CH is charged to VS It is. When the control signal CTL goes to L level, the diode D1 conducts, a potential difference occurs between VS and VG, and the transistor TR1 becomes 0FF. Therefore, the capacitor CH is held at the immediately preceding potential V 0. Buffer amplifier 2 outputs V = V 0. This configuration is effective when the signal whose variation is to be detected is an AC signal.

Fig. 13 5 is a circuit diagram of the discrimination level setting circuit 7 13 that performs initial setting by changing the threshold and the hysteresis width, and according to the center value of the two threshold levels, It shows a changer that changes the threshold and the hysteresis width. The center value of the threshold value is determined by changing the VR of the resistor R1 as the initial setting circuit 711. VB is input via the buffer to the + input of the buffer in the change amount detection circuit 7 12 in the initial setting shown in Figure 13 1 according to the output V 2 of the differential amplifier in Figure 13 1. Current source current I 1 = (V 2-V _BE ) / R 1. When the output of the detection device is 0 FF, hys is at the H level, and the transistor TR1 is in the OFF state. Therefore, I0 = (R2 / R4) XII, Vthl = Vref + R8xlO, Vth2 = Vref-R9xI0. When the output of the detection device is 0 N, hys is at the L level and the transistor TR 1 is set to 0 N. Therefore, I0 ^ ((R2 // R5) ZR4) xI1, Vthl = Vref + R8xI0, Vth2 = Vrei-R9XI0. Therefore, the voltage between the two thresholds and the hysteresis width change according to the voltage at the center of the threshold. I do. If this configuration is adopted, a stable light receiving signal can be obtained because there is no change in the differential amplifier circuit (706 in FIG. 125).

 (7c) Example 7c

 The circuit diagram of the embodiment 7c is shown in Fig. 136, and the timing chart of the operation is shown in 137a to 137g. In this embodiment, three photodiodes PD1, PD2, and PD3 are used as detection elements. As described above, when there are two detection elements, there is no contrast on the detection object surface, and a large object that covers the entire field of view cannot be detected. On the other hand, by expanding the field of view by using three detection elements and amplifying each detection signal as shown in the figure, it is also possible to detect large objects with the output of the differential amplifier AMP3 .

 Thus, more reliable detection can be performed by determining the number of detection elements according to the size of the detection object and the area to be detected. Note that the initial setting may be performed using any of the various methods described above. Industrial applicability

 As described above, the object detection device according to the present invention is an automatic water supply device in a washroom or a toilet, or a detector for operating a machine that needs to be automatically operated only when a person is present. It is particularly suitable for use in automatic operation control of equipment where energy saving is required.

Claims

The scope of the claims

1. A detecting device for optically detecting the presence or absence of an object, comprising: an optical system; and a light detecting element configured to form a plurality of light receiving fields by a light detecting element that receives light passing through the optical system;

 An object detection device, comprising: a light amount fluctuation detecting unit configured to detect a light amount fluctuation between the plurality of light-receiving fields based on an output from the light detection element.

 2. The apparatus according to claim 1, wherein said optical system includes an optical fiber.

 3. The apparatus according to claim 1, wherein the background includes a pattern composed of a first color and a second color different from the first color.

 4. The apparatus according to claim 3, wherein the first color includes a light color, and the light-colored pattern is formed of a luminous body.

 5. The device according to claim 1, wherein the optical system includes a light receiving lens.

 6. The object detection device according to claim 1, wherein the light receiving visual fields are adjacent to each other.

 7. The object detection device according to claim 6, wherein the photodetection element is constituted by a plurality of divided photodiodes.

 8. The object detecting device according to claim 1, wherein the light receiving field of view is constituted by a plurality of the light receiving means.

9. The plurality of light-receiving fields are spaced apart from each other. Item 9. The object detection device according to Item 8.

 10. The object detection device according to claim 8, wherein the plurality of light-receiving fields overlap.

 11. A water supply unit that controls water supply by opening and closing a valve, a water washer supplied from the water supply unit, a sensing unit that senses that the water washer has been used, and a sensing signal from the sensing unit A control unit that outputs a signal for opening and closing the valve of the water supply unit based on the following.A battery is used as a driving power source, and the detection unit described in claim 1 is used for the sensing unit. Characteristic water supply control device.

 1 2. In a transaction device such as an automatic ticketing machine that enables transaction processing when the presence of a person is detected, the detection device described in claim 1 is used for detecting the human body. Transaction machines such as automatic ticketing machines.

 13. A display device which is turned on when the presence of a person is detected, wherein the detection device according to claim 1 is used for detecting the human body. o

 1. A pachinko ball-feeding device which is powered on when the presence of a person is detected, wherein the detection device according to claim 1 is used for detecting the human body. . ,

15. Automatic lighting or an air conditioner that is turned on when the presence of a person is detected, characterized in that the detecting device according to claim 1 is used for detecting the human body. or Is an air conditioner.

 16. An automatic door device which automatically opens a door when a human body is detected, wherein the human body is detected using the detection device according to claim 1.

 17. A detection device for optically detecting the presence or absence of an object, comprising: a light-receiving lens; a light-receiving unit that forms a light-receiving field by a light-detecting element that receives light passing through the light-receiving lens; A signal processing means for detecting a change in the position of the center of gravity of the light in the light receiving visual field by performing signal processing on an output from the detection element.

 1 8. A passive detection device that detects the presence or absence of an object.

 A detection element for detecting a physical quantity,

 An amplifier for amplifying the output from the detection element;

 Judging means for judging the state of the detection target from the output of the amplifier,

 Switch means for periodically interrupting transmission of the output of the detection element to the amplifier.

 19. The determining means changes the output when the magnitude of the signal for each pulse pulsed by the switch means and amplified by the amplifier exceeds a predetermined value by a predetermined number of times, 19. The object detection device according to claim 18, wherein:

20. The determining means

Pulsed by the switch means and amplified by the amplifier First comparing means for binarizing the received signal into a binary pulse based on a magnitude relationship with a predetermined reference value;

 An integrating means for integrating an output of said first comparing means, and a second comparing means for binarizing and outputting the output of said integrating means based on a magnitude relationship with a predetermined reference value. Item 19. The object detection device according to Item 18.

 21. The object detection device according to claim 18, further comprising a filter that passes a signal in a band including a switching frequency of the switching means.

22. The object detection device according to claim 18, wherein the detection element is configured by a light detection element.

23. The object detection device according to claim 18, wherein the detection element is an infrared detection element.

 24. The object detection device according to claim 18, wherein the detection element is a temperature sensor.

 25. The object detection device according to claim 18, wherein the detection element is a pressure sensor.

 26. The object detection device according to claim 18, wherein the detection element is a humidity sensor.

 27. The object detection device according to claim 18, wherein the detection element is a gas sensor.

 28. A passive detector for detecting the detected object by receiving light from the detected object,

Configuring a plurality of light-receiving fields; Light receiving means for receiving light from a detected object or a background object by a plurality of light receiving elements and outputting detection signals of a plurality of systems based on the amount of received light;

 Gate means for respectively time-dividing each of the detection signals of the plurality of systems,

 Pulse generation means for supplying a pulse signal to the gate means so that the timing at which the detection signals pass through the gate means is asynchronous and time-division;

 A signal processing means for detecting a light quantity fluctuation between the light receiving fields by performing signal processing in one system by combining the respective detection signals time-divided by the gate means. .

 29. A control means for controlling supply of power to the signal processing means,

 29. The package according to claim 28, wherein said control means supplies power in synchronization with a pulse of said pulse generation means and for a time necessary for said signal processing means to process said combined detection signal. Shiv type detector.

 30. A passive detector for detecting the detected object by receiving light from the detected object,

 A plurality of light-receiving fields, light-receiving means for receiving light from the detected object or the background object present in the light-receiving field, and outputting a light-receiving signal based on the amount of received light;

The presence or absence of the detected object is determined based on the output of the light receiving unit. Determining means for determining;

 A supplementary light projecting unit for projecting supplementary / assisting light toward the inside of the light receiving field according to the output of the determining unit.

 3 1. The detector further includes output display means for displaying a detection output,

 30. The passive type detector according to claim 30, wherein said display means and said auxiliary light projecting means are shared.

32. The light receiving unit is a light receiving unit that receives light emitted by the auxiliary light projecting unit and reflected by the detected object, and is projected from a light source different from the auxiliary light projecting unit. 30. The detector according to claim 30, wherein said detector shares a light receiving unit for receiving light reflected by said detected object.

33. The light receiving unit is a first light receiving unit that receives light emitted by the auxiliary light projecting unit and reflected by the detected object, and a light source different from the trapping light projecting unit. A second light-receiving portion that receives light reflected by the detected object.

30. The detector according to claim 30, comprising two light receiving units.

 34. The determination means comprises: a first light reception signal when the light receiving means receives light from a light source different from the auxiliary light projection means; and a light reception signal when the auxiliary light is received by the auxiliary light projection means. No.

 30. The passive detector according to claim 30, wherein the presence / absence of the detected object is determined based on a combination with two light receiving signals.

3 5. By receiving light from the object to be detected, A passive type detector that detects a detection object,

 A plurality of light-receiving fields, light-receiving means for receiving light from the detected object or the background object present in the light-receiving field, and outputting a light-receiving signal based on the amount of received light;

 A signal processing unit including: a calculation unit that calculates the light reception signal; and a determination unit that determines the presence or absence of the detected object based on a comparison between an output of the calculation unit and a predetermined threshold value.

 Output means for outputting a detection output by the signal processing means to the outside,

 A passive type detector comprising: illuminance detection means for detecting illuminance in the light-receiving field; and output inhibition means for inhibiting output of the detection output in accordance with the illuminance detected by the illuminance detection means.

 36. A passive object detection device that detects an object by receiving light that is not the light emitted by the detection device itself.

 A light detection unit that outputs two light reception signals,

 Differential operation means for performing a differential operation on the two light receiving signals; determining means for determining the presence or absence of an object based on a comparison between an output of the differential operation means and two thresholds;

Adjusting means for adjusting the output of the differential arithmetic means so that the output of the differential arithmetic means has a predetermined value in an initial state; and adjusting for detecting the amount of the differential arithmetic output adjusted by the adjusting means. Quantity detection means; A threshold value setting unit that sets the two threshold values or the hysteresis width given to each of the threshold values based on the output of the adjustment amount detection unit.

 37. A passive object detection device that detects an object by receiving light that is not the light emitted by the detection device itself.

 A light detection unit that outputs two light reception signals,

 Differential operation means for calculating the two light receiving signals,

 Determining means for determining the presence or absence of an object based on a comparison between the output of the differential operation means and two thresholds;

 Adjusting means for adjusting the output of the differential operation means so that the output of the differential operation means has a predetermined value in an initial state; and adjusting for detecting an amount of two threshold values adjusted by the adjustment means. Quantity detection means;

 A threshold setting means for setting a hysteresis width given to each of the thresholds based on an output of the adjustment amount detecting means.

 3 8. A passive detection device that detects an object by receiving light that is not the light emitted by the detection device itself.

 Two light receiving and light detecting units for outputting light signals,

Differential operation means for performing a differential operation on the two light receiving signals; determining means for determining the presence or absence of an object based on a comparison between an output of the differential operation means and two thresholds; Adjusting means for interlockingly adjusting the two threshold values so that the output of the differential operation means is substantially the center value of the two threshold values in an initial state;

 Adjusting amount detecting means for detecting an amount adjusted with respect to the two threshold values by the adjusting means;

 An object or the like detection device comprising: threshold value setting means for setting an interval between the two threshold values or a hysteresis width given to each threshold value based on an output of the adjustment amount detection means.