TWI468653B - Micro spectrometer capable of receiving zeroth-order and first-order spectrum components - Google Patents

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.

The photometry of the radiation source is usually measured using a spectrometer, which requires a slit structure to control a certain amount of light source into it, and then a diffraction grating to cooperate with a collimator and a correction lens ( The combination of correcting lenses 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 diagram 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 the 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. 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 a plurality of spectral components, in order to focus the 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 zero-order spectral components and the focus position of the first-order spectral components far away, and the general photosensor The length is also limited, so this feature cannot be achieved. Applicants are not sure if the following technologies are conventional techniques. In order to obtain the signals of the zero-order spectral components and the first-order spectral components 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. However, this method is not convenient and will increase the cost and is not economical. 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. The zero-order spectral components of the spectrometer have long been used without being extracted. Therefore, in order to obtain all the diffracted light intensities, the spectral components of the first, second, and third order must be added together, and since the spectral components other than the zeroth order are separated by the wavelength length, the summation itself will be required. It consumes 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 the intensity of the diffracted light, various applications of zero-order light (such as calibration, alignment, etc.) will be difficult to achieve in conventional spectrometers.

Accordingly, it is an object of the present invention to provide a miniature spectrometer capable of receiving zero-order spectral components and first-order spectral components, breaking the position of the prior art for spectrometers, and obtaining the total intensity of the diffracted light, as a special measurement calculation, correction, and For the purpose of 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 unit is configured to receive an optical signal. The micro-diffraction grating has a focusing curved surface and a diffraction pattern formed on the focusing curved surface, and is configured to receive an optical signal and separate the optical signal into a plurality of spectral components, wherein the spectral components include a zero-order spectral component and a first-order spectral component. Component. The photo sensor has a first sensing section and a second sensing section for receiving 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 is configured to receive an optical signal. The micro-diffraction grating receives the optical signal and is used to separate 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 focus the spectral components on the photo sensor, thereby shortening the spectrometer Optical path. The second wafer section has a reflective surface. A light sensor is used to receive the spectral components. The waveguide device includes a first waveguide piece and a second waveguide piece facing each other to define a light path together with the input portion, the micro diffraction grating and the photo sensor. The first waveguide sheet is located on an upper surface of one of the first wafer segments. The second waveguide sheet is in partial contact with the reflective surface of the second wafer segment such that the first portion of the optical signal reaches the diffraction pattern, and the second portion of the optical signal reaches the reflective surface and is 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.

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 a zero-order spectral component and a first-order spectral component 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 unit 10 includes, for example, a slit for receiving 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 (shown in detail in FIG. 4) formed on the focusing curved surface 23, and is used for receiving the optical signal SO and separating the optical signal SO into a plurality of spectra. Component SO0, SO1, SO2, etc. It is worth noting that the spectral components SO0, SO1, and SO2 include a zero-order spectral component SO0, a first-order spectral component SO1, a second-order spectral component SO2, 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 the micro winding. The spectral components SO0, SO1, SO2, etc., which are separated and focused by the grating grating 20. The first sensing section 32 receives the zero-order spectral component SO0 and the second sensing section 34 receives the first-order spectral component SO1. 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 SO2, the third-order spectral component, the fourth-order spectral component, and the like.

In this embodiment, the first sensing section 32 and the second sensing section 34 are arranged in a line and connected. The photo sensor 30 has a plurality of photosensitive cells 36, which are also arranged in a line.

In addition, the micro spectrometer 1 may further include a light emitting device 40, a waveguide device 60, and a casing 80. The input unit 10, the micro-diffraction grating 20, the photo sensor 30, and the waveguide device 60 are mounted in the casing 80. The illuminating device 40 is configured to generate a light signal SO after passing a sample 50 (for example, a chemical to be tested). In this way, the micro 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 is configured to receive the optical signal SO. The micro-diffraction grating 20 receives the optical signal SO and is used to separate the optical signal SO into a plurality of spectral components SO0, SO1, SO2, . The micro-diffraction grating 20 includes a first wafer segment 22 and a second wafer segment 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, SO1, SO2, ... and focus the spectral components on the light. On the sensor 30, thereby shortening 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 typically a substrate or portion thereof used in the microelectromechanical process to scribe the diffraction pattern 24 and has a reflective surface 27. The photo sensor 30 is configured to receive the spectral components SO0, SO1, and SO2. 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 defined together with the input portion 10, the micro-diffraction grating 20, and the photo sensor 30. A light channel 66. The first waveguide sheet 62 is located on an upper surface 25 of one of the first wafer segments 22. The second waveguide 64 is in partial contact with the reflective surface 27 of the second wafer section 26 such that a first portion of the optical signal SO, SOA, reaches the diffraction pattern 24 and a second portion of the optical signal SO, SOB, 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 SOB of the optical signal SO. The second portion 27B is in contact with the second waveguide sheet 64 and is thus blocked by the second waveguide sheet 64 without receiving the optical signal.

The so-called miniature spectrometer in which the micro-diffraction grating 20 is manufactured by a microelectromechanical 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 light tunnel 66 is generally between several tens of micrometers and hundreds of micrometers, compared to the internal light source of the conventional spectrometer. An open space reaches a planar grating 140 and is split, and the optical path 66 of the micro spectrometer is extremely flat. In one example, the height of the light tunnel 66 is 150 microns. miniature The total thickness (H22 + H26) of the 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 microns included in the light tunnel 66. The second portion SOB of the optical signal SO can be reflected by the reflective surface 27. The results measured according to this size are shown in Fig. 4. In FIG. 4, the horizontal axis represents the pixel number of the photo sensor 30, and the vertical axis represents 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 or first order light appears above the pixel number of 700, and the picture of the pixel number 1-700 is drawn. The element senses zero-order light and light that is directly reflected by 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 has no focusing effect, so the optical signal SOB spreads to hundreds of paintings of the sensor. The segment of the prime. 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 of the pixel number 150 senses the intensity of the light reflected by the diffraction pattern 24 and the intensity of the light reflected by the reflection surface 27, so that the total intensity of the sum 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 the end from 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 will There is a change, so the width of section BB will be changed.

Figure 5 is a schematic diagram illustrating the reason why the miniature spectrometer of the present invention can focus on a straight line sensor in the conventional theory of Rowland circle. As shown in FIG. 5, according to the theory of Rowland circle, the incident light passes through the input portion 10 of the slit structure, for example, and is diffracted by the micro-diffraction grating 20' and focused and imaged on the Roland circle RC. Thus, a photosensor 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, only the spectral components can be focused and imaged at two points of the line. Changing the pitch can change the size of the Roland circle, so the diffraction pattern is designed to have a non-fixed pitch, and at least three spectral components can be focused on a straight line, that is, the effect of FIG. 1 is achieved.

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. As shown in FIG. 6, the spectrometer 1 of the present embodiment is similar to FIG. 1, except that the angle between the first sensing section 32 and the second sensing section 34 in the photo sensor 30 is not equal to 0 degrees or 180 degrees. In this way, the zero-order and first-order spectral components can be sensed using the two sensing sections of the photosensor, respectively, when the zero-order spectral component is not coplanar with the focal plane of the first-order spectral component.

7 shows a schematic diagram of a spectrometer capable of receiving a zero-order spectral component and a first-order spectral component in accordance with yet another embodiment of the present invention. As shown in FIG. 7, the embodiment is similar to the first embodiment, except that the spectrometer 1 further includes a stray light filtering structure 90 for filtering out the optical signal SO. One of the stray light components SOC. 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 94T that faces the first toothed structure 92T. A channel 96 is defined between the first tooth structure 92T and the second tooth structure 94T for the non-stray light components SOA, SOB in the optical signal SO to pass. 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 should be noted that the stray light component SOC may include an optical signal to be measured when the incident angle is not correct, in addition to the noise. In the case where the stray light filtering structure 90 is not provided, 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 spectral components and affect the interpretation results of the photosensor. The thickness of the stray light filtering structure can be quite thin and can be made of metal, plastic or semiconductor materials. When the inventor implemented the architecture according to FIG. 1, the results of installing a stray light filtering structure and a 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 of this case does have a substantial improvement in its performance, and is particularly suitable for miniature spectrometers.

By sensing the zero-order spectral component, the user does not need to In the case where the spectral components are summed, the total light intensity output by the micro-diffractive grating 20 can be quickly obtained, and the user can use the data for correction, positioning or other subsequent processing, such as calculating the ratio of the first-order spectral components, second order. The ratio of the spectral components, etc.

The specific embodiments of the present invention are intended to be illustrative only and not to limit the invention to the above embodiments, without departing from the spirit of the invention and the following claims. The scope of the invention and the various changes made are within the scope of the invention.

RC‧‧‧Roland

SO‧‧‧ optical signal

SOA‧‧‧Part 1 (non-stray light components)

SOB‧‧‧Part 2 (non-stray light components)

SOC‧‧‧ stray light components

SO0, SO1, SO2‧‧‧ spectral components

1‧‧‧ Spectrometer

10‧‧‧ Input Department

20, 20'‧‧‧ miniature diffraction grating

22‧‧‧First wafer section

23‧‧‧Focused surface

24‧‧‧Diffraction pattern

25‧‧‧ upper surface

26‧‧‧Second wafer section

27‧‧‧reflecting surface

27A‧‧‧Part 1

27B‧‧‧Part II

30‧‧‧Light sensor

32‧‧‧First sensing section

34‧‧‧Second sensing section

36‧‧‧Photosensitive unit

40‧‧‧Lighting device

50‧‧‧sample

60‧‧‧Wave device

62‧‧‧First waveguide

64‧‧‧Second waveguide

66‧‧‧Light channel

80‧‧‧shell

92‧‧‧First filter section

92T‧‧‧First tooth structure

94‧‧‧Second filter section

94T‧‧‧second tooth structure

96‧‧‧ channel

100‧‧‧ Spectrometer

110‧‧‧Light source

120‧‧‧ Input Department

130‧‧ ‧collimating mirror

140‧‧‧Flat grating

150‧‧‧Focus mirror

160‧‧‧Linear light sensor

170‧‧‧Mirror

180‧‧‧Light sensor

200‧‧‧Optical signal

1 shows a schematic diagram of a miniature spectrometer capable of receiving zero-order spectral components and first-order spectral components in accordance with a preferred embodiment of the present invention.

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

Figure 3 is a schematic illustration of the operation of a diffraction grating in accordance with 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 of the 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 shows a schematic diagram of a spectrometer capable of receiving a zero-order spectral component and a first-order spectral component in accordance with yet another embodiment of the present invention.

Figure 8 shows a schematic of a conventional spectrometer.

SO‧‧‧ optical signal

SOA‧‧‧Part 1

SOB‧‧‧Part II

SO0, SO1, SO2‧‧‧ spectral components

1‧‧‧ Spectrometer

10‧‧‧ Input Department

20‧‧‧Micro Diffraction Grating

23‧‧‧Focused surface

24‧‧‧Diffraction pattern

27‧‧‧reflecting surface

30‧‧‧Light sensor

32‧‧‧First sensing section

34‧‧‧Second sensing section

36‧‧‧Photosensitive unit

40‧‧‧Lighting device

50‧‧‧sample

60‧‧‧Wave device

80‧‧‧shell

Claims (15)

A miniature spectrometer capable of receiving a zero-order spectral component and a first-order spectral component, comprising: an input portion for receiving an optical signal; and a micro-diffraction grating having a focusing surface and a diffraction pattern formed on the focusing surface a pattern for receiving the optical signal and for separating the optical signal into a plurality of spectral components, the spectral components comprising at least a zero-order spectral component and a first-order spectral component; and a light sensor having a first sense a measurement section and a second sensing section for receiving the spectral components separated and focused by the micro-diffraction grating, wherein the first sensing section receives the zero-order spectral component, the first The second sensing section receives the first-order spectral component, and the first sensing section is coupled to the second sensing section. The spectrometer of claim 1, wherein the first sensing section and the second sensing section are arranged in a line, the photo sensor has a plurality of photosensitive units, and the photosensitive units are arranged in a line. And the number of the spectral components is greater than or equal to two. The spectrometer of claim 1, further comprising a light emitting device for emitting a light through a sample to generate the optical signal. The spectrometer of claim 1, further comprising: a housing, wherein the input portion, the micro-diffraction grating, and the photo sensor are mounted in the housing. The spectrometer of claim 1, wherein the spectral components further comprise a second-order spectral component, and the photosensor is The second sensing section further receives the second order spectral component. The spectrometer of claim 1, wherein an angle between the first sensing section and the second sensing section is not equal to 0 degrees or 180 degrees. A miniature spectrometer comprising: an input portion for receiving an optical signal; a micro-diffraction grating for receiving the optical signal and for separating the optical signal into a plurality of spectral components, the micro-diffraction grating comprising a first a wafer segment and a second wafer segment, the first wafer segment having a focusing curved surface and a diffraction pattern formed on the focusing curved surface, the second wafer segment having a reflecting surface; a light sensing And receiving the spectral components separated and focused by the micro-diffractive grating; and a waveguide device including a first waveguide sheet and a second waveguide sheet, the two facing each other to input with the input The micro-diffraction grating and the photo sensor together define an optical channel, the first waveguide is located on an upper surface of the first wafer segment, the second waveguide and the second wafer segment The reflective surface is in partial contact such that a first portion of the optical signal reaches the diffraction pattern and a second portion of the optical signal reaches a portion of the reflective surface that is not in contact with the second waveguide. The micro spectrometer of claim 7, wherein: the spectral components comprise a zero-order spectral component and a first-order spectral component; and the photo sensor has a first sensing segment and a second sensing region. Segment, the first sensing section receives the zero-order spectral component, the second sensing The segment receives the first-order spectral component, and the first sensing segment and the second sensing segment simultaneously receive the second portion of the optical signal reflected from the reflective surface. The spectrometer of claim 8, wherein the first sensing section and the second sensing section are arranged in a line, the photo sensor has a plurality of photosensitive units, and the photosensitive units are arranged in a line. And the number of the spectral components is greater than or equal to two. The spectrometer of claim 8 further comprising a light-emitting device for emitting a light through a sample to generate the optical signal. The spectrometer of claim 8, further comprising: a housing, wherein the input portion, the micro-diffraction grating, the photo sensor, and the waveguide device are mounted in the housing. The spectrometer of claim 8, wherein the spectral components further comprise second-order spectral components, and the second sensing segment of the photosensor further receives the second-order spectral components. The spectrometer of 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 of claim 7, further comprising a stray light filtering structure for filtering out one of the stray light components of the optical signal, the stray light filtering structure comprising: a first filtering section Having a first toothed structure; and a second filter section having a second toothed structure facing the first toothed structure, defined between the first toothed structure and the second toothed structure An optical channel is provided for the passage of non-stray light components in the optical signal. The spectrometer of claim 14, wherein the first filter section and the second filter section are on the same plane.