WO2011120234A1

WO2011120234A1 - Micro spectrometer capable of receiving zero order and first order spectral components

Info

Publication number: WO2011120234A1
Application number: PCT/CN2010/071541
Authority: WO
Inventors: 柯正浩
Original assignee: 晶兆科技股份有限公司
Priority date: 2010-04-02
Filing date: 2010-04-02
Publication date: 2011-10-06
Also published as: CN102812340B; CN102812340A

Abstract

A micro spectrometer (1) capable of receiving zero order spectral component (SO0) and first order spectral component (SO1) comprises an input part (10) for receiving optical signals, a micro diffraction grating (20) and a light sensor (30). The diffraction grating (20) has a focusing curved surface (23) and diffraction patterns (24) formed on the focusing curved surface (23), receives optical signals (SO) and separates the optical signals (SO) into a plurality of spectral components including the zero order spectral component (SO0) and the first order spectral component (SO1). The light sensor (30) has a first sensing portion (32) and a second sensing portion (34), and receives the spectral components separated and focused by the diffraction grating (20). The first sensing portion (32) receives the zero order spectral component (SO0), and the second sensing portion (34) receives the first order spectral component (SO1).

Description

Miniature spectrometer capable of receiving zero-order spectral components and first-order spectral components

The present invention relates to a spectrometer, and more particularly to a spectrometer capable of receiving a zero-order spectral component and a first-order spectral component.

Background technique

The photometry of the radiation source is usually measured using a spectrometer. The spectrometer needs to use a slit structure to control a certain amount of light source into it, and then pass through the diffraction grating to match the collimator (collimator and correcting lens (correcting lens) The combination of the lens focuses the output spectral components on an image plane. A light sensor can be placed on the image plane so that individual spectral components can be obtained.

Figure 8 shows a schematic of a conventional spectrometer 100. As shown in FIG. 8, the conventional spectrometer 100 includes a light source 110, an input portion 120, a collimating mirror 130, a planar grating 140, a focusing mirror 150, and a linear photo sensor 160. The light source 110 outputs an optical signal 200 through the input portion 120 and is then processed by the collimating mirror 130 to reach the planar grating 140. The macroscopic profile of the diffraction pattern 142 of the planar grating 140 is a plane, and the planar grating 140 is more suitable for the conventional processing method of scribing the diffraction pattern with a diamond knife, but it is therefore impossible to make the contour of the grating into a focusing effect. The curved surface, therefore, after the planar grating 140 separates the optical signal into several spectral components, in order to focus these spectral components on the linear photosensor 160, it is necessary to add the focusing mirror 150. Therefore, the optical path of the entire spectrometer 100 is long and relatively bulky.

Therefore, the traditional spectrometer cannot receive the zero-order spectral components and the first-order spectral components at the same time, because the long optical path makes the focal position of the zero-order spectral components and the first-order spectral components far away, and the general optical sensor The length is also limited, so this function cannot be achieved. In order to obtain a signal of a zero-order spectral component and a first-order spectral component in a conventional spectrometer, Applicants believe that a movable mirror 170 and another photosensor 180 can be used. When it is desired to measure the zero-order spectral components, the mirror 170 is moved to the optical path to reflect the light to the light sensor 180. But this This method is inconvenient and adds cost and does not meet economic benefits. In addition, the zero-order spectral component and the first-order spectral component thus obtained are actually obtained in a time-sharing manner, not at the same time. Therefore, when the signal of the light source 110 changes with time, the signal of the zero-order spectral component obtained by this method will not be reliable. Therefore, conventional spectrometers are usually designed only for first-order spectral components. For a long time, the zero-order spectral components of the spectrometer were not used for extraction. Therefore, in order to obtain all the diffracted light intensities, the first, second, third, and other spectral components must be added together, and since the spectral components other than the zeroth order are separated by the wavelength length, the summation itself will It takes a lot of computational resources, and when the spectrometer cannot receive spectral components other than the second and third orders, the resulting error will be greater. In addition to obtaining the intensity of the diffracted light, various applications of zero-order light (such as correction, alignment, etc.) will be difficult to achieve in conventional spectrometers.

Summary of the invention

Accordingly, it is an object of the present invention to provide a miniature spectrometer capable of receiving a zero-order spectral component and a first-order spectral component, breaking the prior art position of the spectrometer, and obtaining the total intensity of the diffracted light, as a special measurement calculation and correction. Used with the alignment.

To achieve the above object, the present invention provides a miniature spectrometer capable of receiving a zero-order spectral component and a first-order spectral component, comprising an input portion, a micro-diffraction grating, and a photo sensor. The input receives an optical signal. The micro-diffraction grating has a focused curved surface and a diffraction pattern formed on the focused curved surface, and receives the optical signal and separates the optical signal into a plurality of spectral components, the spectral component comprising a zero-order spectral component and a first-order spectral component. The photo sensor has a first sensing section and a second sensing section that receive the spectral components separated and focused by the micro-diffraction grating. The first sensing section receives the zeroth order spectral component and the second sensing section receives the first order spectral component.

The invention also provides a miniature spectrometer comprising an input portion, a micro-diffraction grating, a photo sensor and a waveguide device. The input unit receives an optical signal. The micro-diffraction grating receives the optical signal and separates the optical signal into a plurality of spectral components. The micro-diffraction grating comprises a first wafer segment and a second wafer segment. The first wafer segment has a focusing curved surface and a diffraction pattern formed on the focusing curved surface, and the focusing curved surface and the diffraction pattern can generate the aforementioned spectral components and gather the aforementioned spectral components Focus on the light sensor to shorten the optical path of the spectrometer. The second wafer section has a reflective surface. A light sensor receives the spectral component. The waveguide device includes a first waveguide piece and a second waveguide piece facing each other to define an optical channel together with the input portion, the micro diffraction grating and the photo sensor. The first waveguide sheet is located on an upper surface of the first wafer section. The second waveguide sheet is in partial contact with the reflective surface of the second wafer segment such that a first portion of the optical signal reaches the diffraction pattern and a second portion of the optical signal reaches the reflective surface in contact with the second waveguide sheet Partial.

In this way, the miniature spectrometer can capture the zero-order spectral components for subsequent analysis or processing. DRAWINGS

1 shows a schematic diagram of a micro spectrometer capable of receiving a zero-order spectral component and a first-order spectral component in accordance with a preferred embodiment of the present invention;

Figure 2 shows a side view of a miniature spectrometer in accordance with a preferred embodiment of the present invention;

3 is a schematic view showing the operation of a diffraction grating according to a preferred embodiment of the present invention;

Figure 4 shows the results measured by a miniature spectrometer in accordance with a preferred embodiment of the present invention; Figure 5 shows a schematic view of a Rowland circle;

6 shows a schematic diagram of a spectrometer capable of receiving a zero-order spectral component and a first-order spectral component in accordance with another embodiment of the present invention;

7 is a schematic diagram showing a spectrometer capable of receiving a zero-order spectral component and a first-order spectral component according to still another embodiment of the present invention;

Figure 8 shows a schematic of a conventional spectrometer.

Reference number:

RC: Roland Round

SO: optical signal

S0A: Part 1 (non-stray light components)

SOB: Part 2 (non-stray light components)

S0C: stray light component

SO0, S01, S02: spectral components 1: Spectrometer

10: Input section

20, 20': Micro diffraction 22: First wafer section 23: Focused surface 24: Diffraction pattern 25: Upper surface

26: second wafer section 27: reflective surface

27A: Part 1 27B: Part 2 30: Light Sensor 32: First Sensing Section 34: Second Sensing Section 36: Photosensitive Unit 40: Illuminating Device 50: Sample

60: waveguide device 62: first waveguide piece 64: second waveguide piece 80: housing

92: First filter section 92T: first toothed knot 94: second filter section 94T: second toothed knot 96: optical channel 100: Spectrometer

110: light source

120: Input section

130: Collimating mirror

140: Planar grating

142: Diffraction pattern

150: Focusing mirror

160: Linear light sensor

170: Mirror

180: Light sensor

200: optical signal

detailed description

In order to make the above description of the present invention more comprehensible, a preferred embodiment will be described below in detail with reference to the accompanying drawings.

1 shows a schematic diagram of a miniature spectrometer 1 capable of receiving zero-order spectral components and first-order spectral components in accordance with a preferred embodiment of the present invention. As shown in FIG. 1, the micro spectrometer 1 of the present embodiment includes an input portion 10, a micro diffraction grating 20, and a photo sensor 30.

The input portion 10 includes, for example, a slit that receives an optical signal SO and, if necessary, a filter to filter out unnecessary components.

The micro-diffraction grating 20 has a focusing curved surface 23 and a diffraction pattern 24 formed on the focusing curved surface 23 (the detailed structure is shown in FIG. 4), and receives the optical signal SO and separates the optical signal SO into a plurality of spectral components SO0. , S01, S02, etc. It should be noted that the spectral components SO0, S01, and S02 include a zero-order spectral component SO0, a first-order spectral component S01, a second-order spectral component S02, a third-order spectral component, and a fourth-order spectral component. The photo sensor 30 is, for example, a charge coupled device (CCD) sensor or a CMOS sensor, and has a first sensing section 32 and a second sensing section 34 for receiving micro-diffraction. The spectral component SO0 that the grating 20 separates and focuses on, S01, S02, etc. The first sensing section 32 receives the zero-order spectral component SO0 and the second sensing section 34 receives the first-order spectral component S01. In addition, depending on the length of the sensor used in the actual design, the second sensing section 34 can further receive the second-order spectral component S02, the third-order spectral component, and the fourth-order spectral component. In this embodiment, the first sensing Section 32 and second sensing section 34 are aligned. The photo sensor 30 has a plurality of photosensitive cells 36, which are also arranged in a line.

Further, the micro spectrometer 1 may further include a light emitting device 40, a waveguide device 60, and a casing 80. The input portion 10, the micro-diffraction grating 20, the photo sensor 30, and the waveguide device 60 are mounted in the casing 80. The illumination device 40 emits a light source through a sample 50 (e.g., a chemical to be tested) to produce an optical signal SO. In this way, the miniature spectrometer 1 can be an independent measuring device, and the user can carry the micro spectrometer 1 to any place for detection and achieve the purpose of action.

Figure 2 shows a side view of a spectrometer in accordance with a preferred embodiment of the present invention. Figure 3 is a schematic illustration of the operation of a micro-diffraction grating in accordance with a preferred embodiment of the present invention. Referring to FIGS. 1 through 3, the present invention proposes another combined miniature spectrometer 1 comprising an input portion 10, a micro-diffraction grating 20, a photo sensor 30, and a waveguide device 60. The input unit 10 receives the optical signal SO. The micro-diffraction grating 20 receives the optical signal SO and separates the optical signal SO into a plurality of spectral components SO0, S01, S02o. The micro-diffraction grating 20 comprises a first wafer section 22 and a second wafer section 26. The first wafer section 22 has a focusing curved surface 23 and a diffraction pattern 24 formed on the focusing curved surface 23. The micro-diffraction grating 20 having the focusing curved surface 23 and the diffraction pattern 24 can separate the optical signal SO into the spectral components SO0, S01, S02 and focus the spectral components on the photo sensor 30. Shorten the optical path of the spectrometer. The function of the focusing surface 23 is spectral focusing, and the main function of the diffraction pattern 24 is spectral separation, and the two functions together to achieve the function of separating and focusing the optical signal SO. The second wafer section 26 is generally a substrate or portion thereof used in the microelectromechanical fabrication process to scribe the diffraction pattern 24 and has a reflective surface 27. The light sensor 30 receives the spectral components SO0, S01, and S02. The waveguide device 60 includes a first waveguide sheet 62 and a second waveguide sheet 64, both of which are planar waveguide sheets facing each other to be input to the input portion. 10, micro-diffraction grating 20 and Light sensor 30 collectively defines an optical channel 96. The first waveguide sheet 62 is located on an upper surface 25 of the first wafer section 22. The second waveguide sheet 64 is in partial contact with the reflective surface 27 of the second wafer section 26 such that a first portion SOA of the optical signal SO reaches the diffraction pattern 24 and a second portion SOB of the optical signal SO reaches the reflective surface 27 A portion that is not in contact with the second waveguide sheet 64. The reflecting surface 27 has a first portion 27A and a second portion 27B. The first portion 27A receives the second portion S0B of the optical signal SO. The second portion 27B is in contact with the second waveguide piece 64, so that it is blocked by the second waveguide piece 64 without receiving an optical signal.

The so-called miniature spectrometer, in which the micro-diffraction grating 20 is manufactured by a microelectromechanical manufacturing process (MEMS). The height of the diffraction pattern 24 of the micro-diffraction grating 20 is generally about several tens of micrometers to several hundreds of micrometers, and the height of the optical channel 96 is generally between several tens of micrometers and hundreds of micrometers, compared to the internal light source of the conventional spectrometer. The optical path 96 of the micro spectrometer is extremely flat when it reaches a plane grating 140 in an open space and is split. In one example, the height of the light tunnel 96 is 150 microns. The total thickness (H22 + H26) of the micro-diffraction grating 20 is 625 μm, and the height of the diffraction pattern 24 is 80 μm, that is, H22 of Fig. 3 is equal to 80 μm. Therefore, the second wafer section 26 has a height of 70 μm included in the light tunnel 96. The second portion SOB of the optical signal SO can be reflected by the reflective surface 27. The results measured based on this size are shown in Figure 4. In Fig. 4, the horizontal axis is the pixel number of the photo sensor 30, and the vertical axis is the intensity index.

As shown in FIG. 4, since the surface of the sensor filters out light of a wavelength of about 250 nm or less, the first-order or higher-order light appears above the pixel number 700 in the figure, and the pixel of the pixel number 1-700 is sensed. To zero order light and light reflected directly through the first portion 27A of the reflective surface 27. The section AA represents the optical signal reflected by the first portion 27A of the reflecting surface 27, because the first portion 27A is a flat reflecting surface and does not have a focusing effect, so the optical signal SOB spreads to hundreds of sensors. The segment of the pixel. Because of the optical signal reflected by the first portion 27A, the segment thus increases the overall light intensity by approximately 5000 units. The pixel around pixel number 150 senses the intensity of the light reflected by the diffractive pattern 24 and the intensity of the light reflected by the reflective surface 27, so that the total total intensity is about 66,000 units. It should be noted that the present invention can also be used to correct the positioning of the micro-diffractive grating 20. When the micro-diffraction grating 20 is properly placed, the width of the section BB is fixed, and the width of the section BB is a fixed value which can be derived from optical theory, wherein the section BB is from the end of the section AA. The distance between the peaks of a pre-selected characteristic spectrum. When the micro-diffraction grating 20 is skewed, the entire optical path changes, so the width of the section BB is changed.

Figure 5 is a schematic illustration of the theory of the Rowland circle of the known sensor of the present invention in which the microspectrometer can be focused on a straight line. As shown in Fig. 5, according to the theory of Rowland circle, the incident light passes through the input portion 10 such as the slit structure, is diffracted by the micro-diffraction grating 20' and is focused and imaged on the Roland circle RC. Therefore, a photo sensor 30 that intersects the Roland circle RC can receive at least two spectral components. Since the diffraction pattern of the micro-diffraction grating 20' suitable for the Roland circle has a fixed pitch (Pkch), only the spectral components can be focused and imaged at two points of the line. Changing the pitch changes the size of the Roland circle, so designing the diffraction pattern to have a non-fixed pitch allows the at least three spectral components to be focused on a straight line, which is the effect of Figure 1.

Figure 6 shows a schematic diagram of a spectrometer capable of receiving zero-order spectral components and first-order spectral components in accordance with another embodiment of the present invention. As shown in FIG. 6, the spectrometer 1 of the present embodiment is similar to FIG. 1, except that the first sensing section 32 and the second sensing section 34 are separated, and the first sensing section 32 and the first The angle between the two sensing sections 34 is not equal to 0 or 180 degrees. In this way, two photo sensors can be used to sense the spectral components when the zero-order spectral components are far from the focal plane of the first-order spectral components.

7 shows a schematic diagram of a spectrometer capable of receiving zero-order spectral components and first-order spectral components in accordance with yet another embodiment of the present invention. As shown in FIG. 7, this embodiment is similar to the first embodiment except that the spectrometer 1 further includes a stray light filtering structure 90 that filters out a stray light component SOC in the optical signal SO. The stray light filtering structure 90 includes a first filter section 92 and a second filter section 94, which may be separate components or integrally formed components. The first filter section 92 has a first toothed structure 92T. The second filter section 94 has a second toothed structure 94 facing the first tooth Shaped structure 92T. A channel 96 is defined between the first tooth structure 92A and the second tooth structure 94A for the passage of the non-stray light components S0A, SOB in the optical signal SO. In this embodiment, the first filter section 92 and the second filter section 94 are two sheet structures and are located on the same plane.

It is worth noting that the stray light component S0C may contain, in addition to noise, an optical signal to be measured when the incident angle is incorrect. In the case where the stray light filtering structure 90 is not installed, such an optical signal having an incorrect incident angle passes through the input portion 10, and is reflected by the housing 80 or the internal waveguide several times to reach the micro-diffractive grating 20, Therefore, it will interfere with the diffraction result. In addition, the stray light filtering structure 90 can also be disposed between the diffraction grating 20 and the photo sensor 30.

With the spectrometer of the present invention, unnecessary stray light components can be filtered out to avoid interference with the spectral components and affect the interpretation results of the photosensor. The thickness of the stray light filtering structure can be quite thin, and the material can be metal, plastic or semiconductor materials. When the inventor implemented the structure according to Fig. 1, the results of the stray light filtering structure and the stray light filtering structure were compared, and it was found that a spectrometer equipped with a stray light filtering structure can obtain better interpretation results. . Therefore, the spectrometer in this case does have a significant increase in its performance and is particularly suitable for miniature spectrometers.

By sensing the zero-order spectral component, the user can quickly obtain the total light intensity output by the micro-diffraction grating 20 without adding the spectral components of each order, and the user can use the data to perform correction. , positioning or other subsequent processing, such as calculating the ratio of the first-order spectral components, the proportion of the second-order spectral components, and so on.

The specific embodiments set forth in the detailed description of the preferred embodiments of the present invention are not to be construed as being limited to the scope of the present invention. The various changes made are within the scope of the invention.

Claims

Claim

A micro spectrometer capable of receiving a zero-order spectral component and a first-order spectral component, characterized in that said micro spectrometer comprises:

An input unit receiving an optical signal;

a micro-diffraction grating having a focused curved surface and a diffraction pattern formed on the focused curved surface, and receiving the optical signal and separating the optical signal into a plurality of spectral components, the plurality of spectral components Having at least a zero-order spectral component and a first-order spectral component;

a photo sensor having a first sensing section and a second sensing section, receiving the plurality of spectral components separated and focused by the micro-diffractive grating, wherein The first sensing section receives the zero-order spectral component, and the second sensing section receives the first-order spectral component.

2 . The micro spectrometer according to claim 1 , wherein the first sensing section and the second sensing section are arranged in a line, and the photo sensor has a plurality of photosensitive units. The plurality of photosensitive cells are arranged in a line, and the number of the plurality of spectral components is greater than or equal to two.

The micro spectrometer according to claim 1, wherein the micro spectrometer further comprises a light emitting device, wherein the light emitting device generates a light signal after passing through a sample.

4. The micro spectrometer according to claim 1, wherein the micro spectrometer further comprises:

A housing, the input portion, the micro-diffraction grating, and the photo sensor are mounted in the housing.

5. The micro spectrometer of claim 1, wherein the plurality of spectral components further comprise second order spectral components, and wherein the second sensing segment of the photosensor further receives the Second-order spectral component.

6. The microspectrometer according to claim 1, wherein an angle between the first sensing section and the second sensing section is not equal to 0 or 180 degrees.

7. A miniature spectrometer, characterized in that said micro spectrometer comprises: An input unit receiving an optical signal;

a micro-diffraction grating that receives the optical signal and separates the optical signal into a plurality of spectral components, the micro-diffraction grating comprising a first wafer segment and a second wafer segment, the first wafer The segment has a focusing surface and a diffraction pattern formed on the focusing curved surface, and the second wafer segment has a reflecting surface;

a photosensor that receives the plurality of spectral components separated and focused by the micro-diffractive grating;

a waveguide device comprising a first waveguide sheet and a second waveguide sheet facing each other to define an optical channel together with the input portion, the micro diffraction grating and the photo sensor, The first waveguide sheet is located on an upper surface of the first wafer segment, and the second waveguide sheet is in partial contact with the reflective surface of the second wafer segment to enable one of the optical signals The first portion reaches the diffraction pattern and causes a second portion of the optical signal to reach a portion where the reflective surface is not in contact with the second waveguide sheet.

8. The miniature spectrometer of claim 7 wherein:

The plurality of spectral components comprise a zero-order spectral component and a first-order spectral component;

The photo sensor has a first sensing section and a second sensing section, the first sensing section receives the zero-order spectral component, and the second sensing section receives the first a spectral component of the order, and the first sensing section and the second sensing section simultaneously receive the second portion of the optical signal reflected from the reflective surface.

The micro spectrometer according to claim 8, wherein the first sensing section and the second sensing section are arranged in a line, and the photo sensor has a plurality of photosensitive cells. The plurality of photosensitive cells are arranged in a line, and the number of the plurality of spectral components is greater than or equal to two.

10. The micro spectrometer of claim 8, wherein the micro spectrometer further comprises a light emitting device that emits the optical signal after passing a light source through a sample.

11. The micro spectrometer according to claim 8, wherein the micro spectrometer further comprises: A housing, wherein the input portion, the micro-diffraction grating, the photo sensor, and the waveguide device are mounted in the housing.

12. The microspectrometer of claim 8, wherein the plurality of spectral components further comprise a second order spectral component, and wherein the second sensing segment of the photosensor further receives the Second-order spectral component.

13. The microspectrometer according to claim 8, wherein an angle between the first sensing section and the second sensing section is not equal to 0 or 180 degrees.

The micro spectrometer according to claim 7, wherein the micro spectrometer further comprises a stray light filtering structure, which filters out a stray light component in the optical signal, and the stray light filtering The construct contains:

a first filter section having a first tooth structure;

a second filter section having a second toothed structure facing the first tooth structure, and an optical path defined between the first tooth structure and the second tooth structure The non-stray light component in the optical signal passes.

15. The microspectrometer of claim 14, wherein the first filter zone and the second filter zone are on the same plane.