DE102015209234A1 - Device for emitting and / or receiving acoustic signals - Google Patents

Abstract

The present invention relates to a device (1) for emitting and / or receiving acoustic signals. This device (1) comprises an electroacoustic transducer (2) which has at least two first contacts (3a, 3b, 3c, 3d) which are electrically insulated from one another, via which different regions of the electroacoustic transducer (2) can be excited to oscillate, wherein the device (1) is arranged so that when emitting acoustic signals at each of the first contacts (3a, 3b, 3c, 3d) is applied in each case an electrical signal, wherein the applied electrical signals have a mutually different temporal course, and / or upon receiving acoustic signals at each of the first contacts (3a, 3b, 3c, 3d) is tapped in each case an electrical signal to determine from the different time course of the tapped electrical signals, a swing of the electro-acoustic transducer.

Description

State of the art

The present invention relates to a device for emitting and / or receiving acoustic signals.

For quite some time, tongue frequency meters have proven themselves in many applications. In this case, a plurality of vibration tongues are attached to an acoustically rigid Schwingungseinkoppelelement, which each reach their maximum vibration at different excitation frequencies. An observer sees from the tongue, which shows its greatest excursion, with which frequency the oscillation coupling element is excited.

A disadvantage of such tongue frequency meters is that only a portion of the available means, such as in this case the vibrating tongues, is used. Equivalent to this would be to place a plurality of electroacoustic transducers of different resonant frequency on a membrane and to use another electroacoustic transducer depending on the frequency to be transmitted or received. However, the respectively unused area of the membrane would unnecessarily pull sound energy out of the sound field or cause it to oscillate during a transmission.

From the field of telecommunications, it is known that with frequency modulation, such as frequency hopping, in a very narrow frequency band information with very good reliability, ie separation capability can be transmitted. This is especially true when using orthogonal modulation, as used for example in W-LAN systems.

It is based on analysis of variance, that is, signal analysis by means of second-order moments in the DE 10 2009 027 842 A1 directed. Using variance reciprocal, it is possible to achieve a very good signal synchronization and thus localization with second-order moments.

Current electro-acoustic transducers usually have only two contacts and are therefore optimal for a vibration mode, that is to say exactly one resonance frequency.

DE37337761A1 discloses an ultrasonic probe constructed of a composite piezoelectric material consisting of a plurality of ceramic piezoelectric rod elements embedded in an organic material. Strip electrodes are formed from this composite material to improve flexibility and sensitivity of the probe.

Disclosure of the invention

The device according to the invention for emitting and / or receiving acoustic signals comprises an electroacoustic transducer which has at least two electrically insulated first contacts, via which in each case different regions of the electroacoustic transducer can be excited to oscillate. In this case, the device is set up so that an electrical signal is applied to each of the first contacts when emitting acoustic signals, wherein the applied electrical signals have a mutually different temporal course, and / or upon receiving acoustic signals at each of the first contacts in each case an electrical signal is tapped in order to determine a swinging of the electroacoustic transducer from the different temporal course of the tapped electrical signals.

Such a device is advantageous because a particularly efficient implementation between acoustic signals and electrical signals takes place. That is, the device has a high efficiency in transmitting acoustic signals and high sensitivity in receiving acoustic signals. The device is characterized by a particularly advantageous signal-to-noise ratio, for example noise of an internal resistance of the device. The electroacoustic transducer, in particular when emitting acoustic signals, a predetermined vibration behavior can be impressed, whereby the vibration behavior of the electroacoustic transducer can be precisely controlled and thus optimally adapted to any environmental conditions.

The dependent claims show preferred developments of the invention.

It is advantageous if the first contacts form concentric circles on a surface of the electroacoustic transducer. In particular, it is advantageous if the electroacoustic transducer has the shape of a circular disk. In this way, an arrangement of the contacts is achieved by which individual vibration modes of the electro-acoustic transducer can be excited particularly efficient. At the same time, the contacts have a somewhat complex shape, which simplifies manufacture of the device and at the same time achieves high stability.

It is also advantageous if the different time profile of the electrical signals applied to the first contacts is selected such that the electroacoustic transducer oscillates selectively in a first vibration mode or in a second vibration mode. In particular, the first vibration mode is a vibration mode of a first frequency and the second vibration mode is a vibration mode of a second frequency. It can thus always be chosen a vibration mode, which allows a particularly high sensitivity or a particularly high efficiency of the device. In this case, an adaptation of the device to a desired frequency is made possible.

Furthermore, it is advantageous if the electroacoustic transducer has at least one second contact, which is electrically conductively connected to an associated first contact, wherein the second contact is arranged such that the second contact in response to a predefined incoming acoustic signal with respect to frequency and / or or amplitude and / or phase oscillates in an identical manner as the associated first contact. Thus, a number of electrical signals needed when transmitting acoustic signals through the device are reduced and / or processing of electrical signals when receiving acoustic signals is simplified as those regions of the electroacoustic transducer which cause similar electrical signals are combined.

When receiving acoustic signals, it is equally advantageous to filter each of the electrical signals picked up at the first contacts to a predetermined time profile. In this way, interference when receiving acoustic signals can be particularly efficiently suppressed.

Furthermore, it is advantageous if the device according to the invention comprises a delay unit which is adapted to change a phase of an incoming electrical signal and to apply the incoming electrical signal to one of the first contacts and the incoming electrical signal changed in phase to another of the first create first contacts. In particular, the phase of the incoming electrical signal is changed by means of a passive component. Thus, at least a part of the electrical signals required for emitting an acoustic signal is generated in a particularly simple manner.

It is advantageous if the electroacoustic transducer is a bending oscillator, wherein the first and / or second contacts are arranged on a first side of the electroacoustic transducer and a reference electrode is arranged flat on a second side opposite the first side of the electroacoustic transducer. In this way, the entire first side of the electroacoustic transducer can be used for the first and / or second contacts and a particularly precise excitation of the electroacoustic transducer can take place.

It is also advantageous if the electrical signals applied to the first contacts are chosen such that the acoustic signal emitted or received by the device is within a predetermined frequency range and in particular has a constant frequency. Thus, the device can be operated at such a frequency in which this achieves a particularly high efficiency and has a particularly high sensitivity.

Furthermore, it is advantageous if the acoustic signal emitted or received by the device is an ultrasonic signal. This is advantageous since, especially in the field of transmitting and receiving ultrasound signals, high demands are placed on the sensitivity and efficiency of devices for emitting and / or receiving acoustic signals.

Further, a method for producing a device according to the invention is advantageous in which the electroacoustic transducer is arranged on a membrane and in particular glued to this, a contacting layer on a side facing away from the membrane of the electroacoustic transducer is applied and the first and / or second contacts of the Contacting layer are formed by the areas of the bonding layer, which lie between the first and / or second contacts are removed. Such a method enables a precise arrangement of the contacts and avoids breaking of the electroacoustic transducer.

Furthermore, it is advantageous if the device is set up to be arranged on a vehicle and in particular to be integrated into an electrical system of the vehicle. It is also advantageous if the device is set up to send and / or receive information about the acoustic signal.

Brief description of the drawings

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawing is:

1 a device according to the invention for emitting and / or receiving acoustic signals in a first embodiment of the invention,

2 a representation of an oscillating in a first mode vibration electroacoustic transducer at three successive times,

3 a representation of a vibrating in a second vibration mode electroacoustic transducer at three successive times, and

4 a device according to the invention for emitting and / or receiving acoustic signals in a second embodiment of the invention.

Embodiments of the invention

1 shows a device according to the invention 1 for emitting and / or receiving acoustic signals in a first embodiment of the invention. The device 1 includes an electroacoustic transducer 2 , The electroacoustic transducer 2 is a piezoelectric bending vibrator. The electroacoustic transducer 2 is in 1 shown in a cross section. In a plan view is the electroacoustic transducer 2 a circular disk. The electroacoustic transducer 2 has a first page 6 and one of the first page 6 opposite second side 7 on. The first page 6 and the second page 7 are the flat surfaces of the circular disk.

The electroacoustic transducer 2 lies in a region of its outer circumference on a membrane carrier 8th on, and is at this point with a membrane carrier 8th welded.

The electroacoustic transducer 2 has at least two mutually electrically insulated first contacts 3a . 3b . 3c . 3d on. The at least two mutually electrically insulated first contacts 3a . 3b . 3c . 3d be in this first embodiment by a circular disc-shaped contact 3a , a first annular contact 3b , a second annular contact 3c and a third annular contact 3d educated. The circular disk-shaped contacting 3a has the shape of a circular disk. A center of the circular disc-shaped contacting 3a is so on the electroacoustic transducer 2 arranged this over a center of the electroacoustic transducer 2 lies. The center of the electroacoustic transducer 2 is a center of one of the circular disk-shaped surfaces of the electroacoustic transducer 2 ,

The first annular contact 3b is concentric with the circular disk-shaped contacting 3a arranged. The first annular contact 3b rotates the circular disk-shaped contact 3a , wherein an outer circumference of the circular disc-shaped contacting 3a a distance to an inner circumference of the first annular contact 3b having. The second annular contact 3c is concentric with the circular disk-shaped contacting 3a arranged. The second annular contact 3c rotates the circular disk-shaped contact 3a wherein an outer circumference of the first annular contact 3b a distance to an inner periphery of the second annular contact 3c having. The third annular contact 3d is concentric with the circular disk-shaped contacting 3a arranged. The third annular contact 3d surrounds the second annular contact 3c wherein an outer circumference of the second annular contact 3c a distance to an inner periphery of the third annular contact 3c having. As a material from which the electro-acoustic transducer 2 is manufactured, is not conductive and the first contacts 3a . 3b . 3c . 3d are spaced apart, are the first contacts 3a . 3b . 3c . 3d electrically isolated from each other.

The first contacts 3a . 3b . 3c . 3d are on the second page 7 of the electroacoustic transducer 2 arranged. On the first page 6 of the electroacoustic transducer 2 is a reference electrode 5 arranged. This extends over the entire, on the first page 6 the electroacoustic transducer surface of the electroacoustic transducer 2 ,

We put tension between one of the first contacts 3a . 3b . 3c . 3d and the reference electrode 5 applied, there is an elastic deformation of the electroacoustic transducer in the area in which the first contact 3a . 3b . 3c . 3d is, to which the electrical signal was applied.

Each of the first contacts 3a . 3b . 3c . 3d is in each case via an electrical line with a signal unit 4 coupled. Through the signal unit 4 several, mutually different electrical signals are generated, which are connected to the first contacts 3a . 3b . 3c . 3d be transmitted via the electrical leads to the first contacts. In addition, the signal unit 4 via an electrical line to the reference electrode 5 coupled.

When emitting acoustic signals through the device 1 is to each of the first contacts 3a . 3b . 3c . 3d from the signal unit 4 each applied an electrical signal, wherein the applied electrical signals to each other have different time course. That means the first contacts 3a . 3b . 3c . 3d not be excited by a common electrical signal.

In this first embodiment, the electroacoustic transducer 2 from the signal unit 4 optionally be excited to oscillate either in a first mode of vibration or in a second mode of vibration.

2 shows the electroacoustic transducer 2 at a first time t _1a , at a second time t _1b and at a third time t _1c , wherein the electroacoustic transducer 2 vibrates in the first vibration mode. At the first time t _1a is the electroacoustic transducer 2 arched upwards over its entire surface. At the second time t _1b is the electroacoustic transducer 2 not arched, which also corresponds to its expression in its resting state. At the third time t _1c is the electroacoustic transducer 2 arched down over its entire surface.

It is a position of the circular disk-shaped contacting 3a , the first annular contact 3b , the second annular contact 3c and the third annular contact 3d on the electroacoustic transducer 2 shown. It is first the second annular contact 3c considered. It can be seen that the entire area in which the second annular contact 3c is characterized by a similar vibration behavior. So is the second annular contact 3c in their entirety to each of the in 2 shown at an equal height above a rest position of the acoustic transducer 2 , The same applies to the area of the electroacoustic transducer as well 2 in which the first annular contact 3b is arranged and for the range of the electroacoustic transducer 2 in which the third annular contact 3d is arranged.

It will be apparent that the electroacoustic transducer 2 to the in 2 shown vibration can be excited by each of the first contacts 3a . 3b . 3c . 3d in each case a sinusoidal electrical signal is applied, wherein the sinusoidal electrical signals have a same phase and one to the deflection of the region in which the associated first contact 3a . 3b . 3c . 3d is arranged, having adapted amplitude.

3 shows the electroacoustic transducer 2 in the second vibration mode. In this case, the electroacoustic transducer 2 at a fourth time t _{2a, 2b} and a fifth time t to a time t sechsen _2c. It can be seen that an inner region of the electroacoustic transducer 2 opposite to an outer region of the electroacoustic transducer 2 swings. For example, it can be seen that the range of the electroacoustic transducer 2 in which is the third annular contact 3d located at the fourth time t _2a relative to a rest position of the electroacoustic transducer 2 has moved down, whereas the area of the electroacoustic transducer 2 , in which the first annular contact 3b located opposite the rest position of the electroacoustic transducer 2 has moved upwards. It is thus apparent, by a corresponding excitation of the first contacts 3a . 3b . 3c . 3d the electroacoustic transducer 2 can be forced to vibrate in the second vibration mode. So in the in 3 shown example of each of the first contact 3a . 3b . 3c . 3d each applied a sinusoidal electrical signal, wherein the sinusoidal electrical signals are out of phase with each other. A frequency of the electrical signals in the second oscillation mode may differ from the frequency of the electrical signals in the first oscillation mode.

In the signal unit 4 is in this first embodiment, a time course for a first electrical signal deposited, which is connected to the circular disc-shaped contact 3a is created. Furthermore, a second electrical signal is deposited, which is connected to the first annular contact 3b is created. Furthermore, a third electrical signal is deposited, which is connected to the second annular contact 3c is created. Furthermore, a fourth electrical signal is deposited, which is connected to the third annular contact 3d is created. In this case, all electrical signals are sinusoidal electrical signals, which differ, however, at least in their phase relationship to each other or their amplitude.

In each case, a first to fourth electric stored for the first mode of vibration and each deposited a first to fourth electrical for the second mode of vibration. Deposited means that the signal unit 4 generates the electrical signals upon request. Thus, each of the first contacts 3a . 3b . 3c . 3d applied electrical signals each have a predetermined time course. In the control / evaluation of the electroacoustic transducer 2 a climate dependency of the electrical signals is considered.

In this first embodiment, the electrical signals associated with the first vibration mode have a first frequency f1 and the electrical signals associated with the second vibration mode have a second frequency f2. This causes the electroacoustic transducer 2 by doing oscillates first vibration mode with a first frequency f1 and oscillates in the second vibration mode at a second frequency f2. Both the first frequency f1 and the second frequency f2 are in a high-frequency range, so that the electroacoustic transducer 2 is excited to a vibration that leads to an acoustic signal in the ultrasonic range.

The electrical signals associated with the first vibration mode have a constant frequency. Thus, that also shows that of the electroacoustic transducer 2 generated acoustic signal to a constant frequency. Thus, at the first contacts 3a . 3b . 3c . 3d applied electrical signals selected such that the acoustic signal is at a constant frequency in a predetermined frequency range.

When receiving acoustic signals we at each of the first contacts 3a . 3b . 3c . 3d each tapped an electrical signal and determined from the different time course of the tapped electrical signals swinging of the electro-acoustic transducer. Will the electroacoustic transducer 2 excited by an incoming acoustic signal to a vibration, it is through the electro-acoustic transducer 2 converted into electrical signals. These are the first contacts 3a . 3b . 3c . 3d tapped, in which case each of the first contacts 3a . 3b . 3c . 3d an electrical signal is applied, which in its time course from that at the other first contacts 3a . 3b . 3c . 3d different electrical signals. From each of the first contacts 3a . 3b . 3c . 3d Thus, in each case an electrical signal to the signal unit 4 transfer. The device 1 In this first embodiment, it is designed to receive a specific acoustic signal. Therefore, each of the electrical signals coming from the first contacts 3a . 3b . 3c . 3d to the signal unit 4 is filtered by a matched filter.

The device 1 thus indicates for each of the first contacts 3a . 3b . 3c . 3d an associated matched filter. The matched filters are designed so that they pass only those portions of the electrical signals resulting from the particular acoustic signal. Thus, when receiving acoustic signals, each of the first contacts 3a . 3b . 3c . 3d tapped electrical signals filtered to a predetermined time course out.

Is it the electro-acoustic transducer 2 as in this first embodiment, a bending transducer in the form of a round disc and are the electrical signals from a narrower frequency range, so can the number of necessary first contacts 3a . 3b . 3c . 3d be significantly reduced compared to other embodiments. When transmitting and / or receiving an acoustic signal, the time histories of the voltages of the electrical signals of some of the first contacts 3a . 3b . 3c . 3d with each other close to zero and with other signal forms, such as another frequency, they vary with time, in particular against each other out of phase. The exact relationships of the contact voltage can be determined either experimentally and / or by simulation.

In an optional embodiment, the signal unit comprises 4 a delay unit configured to change a phase of an incoming electrical signal and the incoming electrical signal to one of the first contacts 3a . 3b . 3c . 3d create and changed in its phase incoming electrical signal to another of the first contacts 3a . 3b . 3c . 3d to apply. Thus, for example, the first electrical signal, which at a transmission of the acoustic signal to the circular disk-shaped contact 3a is applied as an incoming electrical signal to the delay unit. By passive components in the delay unit, in particular by a capacitor, a phase of the incoming electrical signal, ie the first electrical signal, is shifted. By a resistance of the delay unit, an amplitude of the incoming electrical signal is changed. The first electrical signal, which is changed in amplitude and in phase, is referred to as the second electrical signal to the first annular contact 3b created.

A second embodiment of the device for emitting and / or receiving acoustic signals is shown in FIG 4 shown. The second embodiment substantially corresponds to the first embodiment. However, the acoustic transducer points 2 a second contact 9 on. The second contact 9 replaces the first annular contact 3b and is with this in shape and location on the electroacoustic transducer 2 identical. The second contact 9 is via an electrical connection with the third annular contact 3d connected. A direct connection between the second contact 9 and the signal unit 4 eliminated.

The second contact 9 and the third annular contact 3b are arranged in this embodiment on the electro-acoustic transducer that the area in which the second contact 9 is arranged and the area in which the third annular contact 3d is arranged for at least one, in particular two, predetermined vibration modes have an identical vibration behavior. The electroacoustic transducer 2 thus has at least a second contact 9 on that with an associated first contact 3a . 3b . 3c . 3d is electrically conductively connected, wherein the second contact 9 is arranged such that the second contact 9 in response to a predefined incoming acoustic signal in terms of frequency and / or amplitude and / or phase oscillates in an identical manner as the associated first contact 3a . 3b . 3c . 3d ,

The second contact 9 and the third annular contact 3d are thus shared by the signal unit 4 output electric signal is excited to generate one of the predetermined vibration modes.

The electroacoustic transducer ideally consists of a large variety of contacts. It can often be assumed that similar charge shifts take place in regions of equal deflection and correspondingly similar voltage potentials exist. According to the invention, the same potentials are thus combined in one contact in order to reduce the effort.

In the following, an exemplary method for producing a device for emitting and / or receiving electroacoustic signals is described. First, a continuous contacting layer on the first side 6 and on the second page 7 of the electroacoustic transducer 2 applied. Then the electroacoustic transducer 2 with his second page 7 arranged on a membrane and glued to it. The areas of the continuous contacting layer on the first side 6 of the electroacoustic transducer 2 will be in areas where none of the first contacts 3a . 3b . 3c . 3d should lie, removed. In order to remove these areas, they are etched out of the continuous contacting layer, cut or milled.

In addition to the advantage that the vibration behavior for each waveform, in particular for a pulse of fixed frequency, can be adjusted so that the functional target, such as maximum frequency and / or phase angle can be optimally achieved, there is a further advantage of the inventive control of electroacoustic transducer 2 in that the electroacoustic transducer 2 for each of the first contacts 3a . 3b . 3c . 3d can be set separately. So can the vibration behavior of the electroacoustic transducer 2 detailed in its course over the electroacoustic transducer 2 be set. For example, the operating limits of a currently common electro-acoustic transducer having only two contacts, among other things, predetermined by the part of the electro-acoustic transducer, which can be destroyed with further increase first. Typical destruction effects are, for example, voltage breakdown or change in the crystal structure as a result of depolarization. If the operating values of each contacting can be set separately, a more efficient use is possible, which can be felt, for example, as a high level of activation.

It is known to the person skilled in the art that alternative derivations of the basic idea according to the invention are also possible, for example by carrying out at least parts of the signal processing with sampled time and value-discrete data signals.

In addition to the above written disclosure, explicit reference is made to the disclosure of 1 to 4 directed.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009027842 A1 [0005]
• DE 37337761 A1 [0007]

Claims (10)

Contraption ( 1 ) for emitting and / or receiving acoustic signals, comprising an electroacoustic transducer ( 2 ), the at least two mutually electrically isolated first contacts ( 3a . 3b . 3c . 3d ), over each of which different areas of the electroacoustic transducer ( 2 ) can be excited to a vibration, wherein the device ( 1 ) is set up so that • when emitting acoustic signals at each of the first contacts ( 3a . 3b . 3c . 3d ) is applied in each case an electrical signal, wherein the applied electrical signals have a mutually different temporal course, and / or • upon receiving acoustic signals at each of the first contacts ( 3a . 3b . 3c . 3d ) is tapped in each case an electrical signal to determine a swing of the electro-acoustic transducer from the different time course of the tapped electrical signals. Device according to claim 1, characterized in that the first contacts ( 3a . 3b . 3c . 3d ) concentric circles on a surface of the electroacoustic transducer ( 2 ) form. Device according to one of the preceding claims, characterized in that the different temporal course of the first contacts ( 3a . 3b . 3c . 3d ) is selected such that the electroacoustic transducer ( 2 ) oscillates either in a first mode of vibration or in a second mode of vibration. Device according to one of the preceding claims, characterized in that the electroacoustic transducer ( 2 ) at least one second contact ( 9 ) associated with an associated first contacting ( 3a . 3b . 3c . 3d ) is electrically conductively connected, wherein the second contact ( 9 ) is arranged such that the second contact ( 9 ) oscillates in response to a predefined incoming acoustic signal in terms of frequency and / or amplitude and / or phase in an identical manner as the associated first contact ( 3a . 3b . 3c . 3d ). Device according to one of the preceding claims, characterized in that when receiving acoustic signals each of the first contacts ( 3a . 3b . 3c . 3d ) tapped electrical signals in each case a predetermined time course is filtered out. Device according to one of the preceding claims, further comprising a delay unit which is adapted to change a phase of an incoming electrical signal, and the incoming electrical signal to one of the first contacts ( 3a . 3b . 3c . 3d ) and the incoming electrical signal changed in its phase to another of the first contacts ( 3a . 3b . 3c . 3d ). Device according to one of the preceding claims, characterized in that the electro-acoustic transducer ( 2 ) is a bending oscillator, wherein the first and / or second contacts ( 3a . 3b . 3c . 3d ) on a first side of the electroacoustic transducer ( 2 ), and a reference electrode ( 5 ) flat on one of the first side opposite the second side of the electroacoustic transducer ( 2 ) is arranged. Device according to one of the preceding claims, characterized in that the at the first contacts ( 3a . 3b . 3c . 3d ) are selected such that the acoustic signal is in a predetermined frequency range and in particular has a constant frequency. Device according to one of the preceding claims, characterized in that the acoustic signal is an ultrasonic signal. Method for producing a device according to one of the preceding claims, characterized in that the electroacoustic transducer ( 2 ) is arranged on a membrane, in particular glued to this, a contacting layer on a side facing away from the membrane of the electro-acoustic transducer ( 2 ) is applied, and the first and / or second contacts are formed from the contacting layer by the areas of the contacting layer, which between the contacts ( 3a . 3b . 3c . 3d ) are removed.

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