A miniature grating spectrometer

Abstract

The present invention relates to a miniature grating spectrometer, comprising: a housing, the housing being provided with a penetrating light inlet; a light homogenizer, the light homogenizer being fixedly connected to the inner side of the housing and covering the light inlet; a first light baffle, arranged on the side of the light homogenizer away from the housing, the first light baffle being provided with a penetrating first incident slit; a diffraction grating, the diffraction grating being arranged on the inner wall of the housing and being on the same optical path as the first incident slit; a detection component, the detection component being fixed in the housing and arranged opposite to the diffraction grating; a computing unit, the computing unit being arranged inside or outside the housing and electrically connected to the detection component. The miniature grating spectrometer of the present invention is composed only of a slit, a grating, a detector and a computing unit. By omitting a collimating element and a focusing element, the optical path is greatly shortened and the size of the spectrometer is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of spectrometers, and in particular to a miniature grating spectrometer. Background Art

[0002] Spectral analysis is the most widely used method in scientific work, and is used to solve basic and applied problems in physics, chemistry, biology, medicine and other disciplines. The spectrometer is an indispensable tool in the spectral analysis method. It is an optical instrument that decomposes complex light into spectral lines. It is composed of prisms or diffraction gratings. By capturing and analyzing light information, the spectrometer can measure the reflected light on the surface of an object and detect the material composition of the object. It is widely used in industries such as air pollution, water quality monitoring, food hygiene, metal industry, and medical applications.

[0003] The current spectrum acquisition technology is mainly based on dispersion spectrometry, including prism spectrometry and grating spectrometry. The most widely used in the market is the grating spectrometer using grating as a dispersion element. The traditional grating spectrometer is usually composed of one or more diffraction gratings, an optical path and a detector array, wherein the optical path generally includes an incident slit, a collimating lens, a focusing imaging system and other parts. After the light to be measured passes through the incident slit, it is collimated by the collimating lens and irradiated on the diffraction grating. The diffraction grating disperses the spectral components in different directions. Finally, the focusing imaging system focuses the scattered light on the detector array to obtain the spectral distribution. Traditional spectrometers have the advantages of high precision, wide application range, and stable structure, but at the same time, they also have the disadvantages of complex structure, limited use environment, inconvenient to carry and high price, which cannot meet the market demand for on-site detection and real-time monitoring. Therefore, the micro-spectrometer has become an important direction for market selection. Compared with the traditional spectrometer, the micro-spectrometer has the same optical structure and detection principle as it. While ensuring the realization of basic functions, it has the advantages of small size, easy to carry, and simple structure.

[0004] In the design of spectral instruments, the Czerny-Turner structure is the most commonly used structure. This structure consists of an incident slit, a collimating element, a dispersion element, a focusing element and a detector, but has the disadvantages of multiple elements and a long optical path. Summary of the invention

[0005] The object of the present invention is to provide a miniature grating spectrometer, which has a simple and compact structure and low manufacturing cost.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A miniature grating spectrometer, comprising:

[0008] A housing, wherein a light inlet is provided through the housing;

[0009] A light homogenizer, which is fixedly connected to the inner side of the housing and covers the light entrance;

[0010] A first light blocking plate is arranged on a side of the light homogenizing plate away from the housing, and a first incident slit is provided on the first light blocking plate;

[0011] a diffraction grating, the diffraction grating being arranged on the inner wall of the housing and being on the same optical path as the first incident slit;

[0012] A detection member, the detection member is fixed in the housing and arranged facing the diffraction grating;

[0013] A computing unit is disposed inside or outside the shell and is electrically connected to the detection element.

[0014] Preferably, the micro-grating spectrometer also includes a fixing part, which is fixedly connected to the side of the light homogenizer away from the light entrance, and the fixing part is provided with a penetrating light-transmitting hole, the first light-blocking plate is arranged on one side of the light-transmitting hole, and the projection of the light-transmitting hole on the first light-blocking plate covers the first incident slit; a second light-blocking plate is provided on the side of the fixing part away from the light homogenizer, and a penetrating second incident slit is provided on the second light-blocking plate, and the projection of the light-transmitting hole on the second light-blocking plate covers the second incident slit.

[0015] Preferably, a first groove is provided on the surface of the fixing member close to the light homogenizing plate, and the first light baffle is embedded in the first groove; a second groove is provided on the surface of the fixing member away from the light homogenizing plate, and the second light baffle is embedded in the second groove; the light-transmitting hole passes through the first groove and the second groove.

[0016] Preferably, the light entrance, the first incident slit, and the second incident slit are arranged in the same plane, and the angle formed by the line connecting the second incident slit and the center point of the diffraction grating and the line connecting the center point of the diffraction grating and the detection element is 30-150°.

[0017] Preferably, the width of the first incident slit and the second incident slit is 50-1000 μm, and the distance between the first incident slit and the second incident slit is 100-3000 μm.

[0018] Preferably, the size of the light homogenizing sheet is 1-80 mm.

[0019] Preferably, the diffraction grating is a plane reflection grating or a concave reflection grating.

[0020] Preferably, the plane reflection grating has a length of 2-50 mm, a width of 2-50 mm, a height of 2-50 mm, a spectral range of 300-1100 nm, and a number of 500-2000 lines; the plane reflection grating and the second incident slit are on the same optical path and have an inclination angle of 10-80°.

[0021] Preferably, the detection element is a detector module or an image sensor group.

[0022] Preferably, the image sensor is a CMOS area array image sensor with a field of view of 40-150°, a focal length of 2-5 mm, and an effective pixel array of 1-1920H×1-1080V.

[0023] Preferably, the shell has a length of 10-80 mm, a width of 10-80 mm, and a height of 10-80 mm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The micro grating spectrometer provided in the above technical solution is composed only of a slit, a grating, a detector and a computing unit. By omitting the collimating element and the focusing element, the optical path is greatly shortened and the size of the spectrometer is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the overall structure provided for an embodiment of the present invention.

[0027] Figure 2 for Figure 1 Section view along plane AA.

[0028] Figure 3 for Figure 1 Another angle cross-sectional view along the AA plane.

[0029] Figure 4 for Figure 2 The enlarged structural diagram at B in the middle. Reference numerals: 1, housing; 11, light inlet; 2, light homogenizer; 3, fixing member; 31, first groove; 32, second groove; 33, light-transmitting hole; 4, first light-blocking plate; 41, first incident slit; 5, diffraction grating; 6, detection member; 7, calculation unit; 8, second light-blocking plate; 81, second incident slit. DETAILED DESCRIPTION

[0030] The present invention will be described in more detail below in conjunction with the accompanying drawings. It should be noted that the description of the present invention with reference to the accompanying drawings is only illustrative and not restrictive. The various embodiments can be combined with each other to form other embodiments not shown in the following description.

[0031] See also Figure 1-4 In an embodiment of the present invention, a miniature grating spectrometer is provided, including a housing 1, a light homogenizer 2, a first light baffle 4, a diffraction grating 5, a detection component 6, and a computing unit 7. The housing 1 is provided with a penetrating light inlet 11, the light homogenizer 2 is connected to the inner side of the housing 1 and covers the light inlet 11, and the light homogenizer 2 can be bonded to the inner side of the housing 1, or fixed to the inner side of the housing 1 by a fastener. The first light baffle 4 is arranged on the side of the light homogenizer 2 away from the housing 1, and a penetrating first incident slit 41 is arranged on the first light baffle 4. The diffraction grating 5 is arranged on the inner wall of the housing 1, and is on the same optical path as the first incident slit 41. The detection component 6 is fixed in the housing 1, and is arranged opposite to the diffraction grating 5. The computing unit 7 can be arranged inside or outside the housing 1, and is electrically connected to the detection component 6.

[0032] The working principle of the micro grating spectrometer in the case of a single slit is as follows: the incident light enters from the light inlet 11, the light becomes more uniform after passing through the light homogenizer 2, and then diffracts after passing through the first incident slit 41, the diffraction grating 5 disperses the incident light, disperses the complex light incident from the slit into monochromatic light, and then reflects it to the detection element 6 at different angles, the detection element 6 receives the light source signal and converts it into an electrical signal and transmits it to the calculation unit 7, which analyzes it to obtain the complex light spectrum information. The analysis result is stored in the calculation unit 7 or output through the data transmission interface provided thereon. If the calculation unit 7 is provided inside the housing 1, a connection hole needs to be opened on the side wall of the housing 1 near the calculation unit 7.

[0033] Preferably, the micro-grating spectrometer further comprises a fixing member 3, which is bonded or fixed by fasteners to a side of the light baffle away from the light entrance 11. A first groove 31 is provided on the surface of the fixing member 3 close to the light homogenizing plate 2, and the first light baffle 4 is embedded in the first groove 31; a second groove 32 is provided on the surface of the fixing member 3 away from the light homogenizing plate 2, and a second light baffle 8 is embedded in the second groove 32. A light-transmitting hole 33 is also provided on the fixing member 3, and the light-transmitting hole 33 passes through the first groove 31 and the second groove 32. A penetrating second incident slit 81 is provided on the second light baffle 8, and the width range of the second incident slit 81 and the first incident slit 41 are both 50-1000μm, and the distance between the second incident slit 81 and the first incident slit 41 is 100-3000μm. In addition, the light inlet 11, the first incident slit 41, and the second incident slit 81 are arranged in the same plane, and the angle formed by the line connecting the second incident slit 81 and the center point of the diffraction grating 5 and the line connecting the center point of the diffraction grating 5 and the detection element 6 is preferably 30-150°, and more preferably 90°. The projections of the first incident slit 41 and the second incident slit 81 on the fixing member 3 are both located in the light-transmitting hole 33. Therefore, the first light baffle 4 and the second light baffle 8 are respectively connected to the two sides of the fixing member 3, that is, the first incident slit 41 and the second incident slit 81 are respectively formed on the two sides of the fixing member 3, so that the incident light is diffracted by the double slits, which can provide a better incident light coherent light source for the spectrometer system.

[0034] The working principle of the micro grating spectrometer with double slits is as follows: the incident light enters from the light inlet 11, and the light becomes more uniform after passing through the light homogenizer 2, and then diffracts through the first incident slit 41, the light-transmitting hole 33, and the second incident slit 81 in sequence. The diffraction grating 5 disperses the incident light, disperses the complex light incident from the slit into monochromatic light, and then reflects it to the detection element 6 at different angles. The detection element 6 receives the light source signal and converts it into an electrical signal and transmits it to the calculation unit 7, which analyzes it to obtain the complex light spectrum information. The analysis result is stored in the calculation unit 7 or output through the data transmission interface provided thereon. If the calculation unit 7 is provided inside the housing 1, a connection hole needs to be opened on the side wall of the housing 1 near the calculation unit 7.

[0035] The housing 1 includes four side walls and two end walls, with a length of 10-80 mm, a width of 10-80 mm, and a height of 10-80 mm. In other embodiments, the side walls of the housing 1 may also be six, eight, etc., or a closed annular surface. The material of the housing may be a metal material or a polymer material. The housing is closed and can provide a light-proof environment for the spectrometer detection system, eliminate the influence of the external ambient light source on the light source to be measured, and also provide a corresponding installation framework for other structures such as the diffraction grating 5 and the detection member 6. The material of the light homogenizer 2 may be fused quartz, sapphire or a polymer material, and the size is 1-80 mm. The light homogenizer 2 can perform multiple light homogenization operations on the incident light beam. When the light beam is incident, the light homogenizer 2 projects the part of the light irradiated thereon as a light spot with uniform energy distribution, and superimposes all the light spots to form a uniform light spot, thereby providing a uniform incident light source for the system, avoiding the phenomenon that the central light intensity of the diffraction grating 5 is high and the edge light intensity is weakened, and improving the diffraction efficiency of the grating.

[0036] The diffraction grating 5 can disperse the complex light incident from the first incident slit 41 into monochromatic light of each wavelength with different diffraction angles, and can be preferably a plane reflection grating with a length of 2-50mm, a width of 2-50mm, a height of 2-50mm, a spectral range of 300-1100nm, and a number of lines of 500-2000. The plane reflection grating has a certain tilt angle, and its tilt angle is preferably 10-80°. Most of the plane reflection gratings are copied by machine-engraved gratings (master gratings), which are low in cost and easy to produce, solve the problem of batch production of gratings, greatly reduce production costs and shorten production cycles, and are easy to assemble and adjust. In other embodiments, concave reflection gratings or other substitute devices with the same principle as the plane grating, such as CD discs, DVDs or blueray-DVD discs, can also be used to replace the plane reflection grating.

[0037] The detection element 6 is a detector module or an image sensor group, such as a surface (line) array CCD or other linear array photoelectric sensors, etc., and can preferably be a complementary metal oxide semiconductor (CMOS) surface array image sensor, with a field of view of 40-150°, a focal length of 2-5mm, and an effective pixel array of 1-1920H×1-1080V, so that the resolution of the spectrometer in the present invention reaches 5-15nm. Compared with the linear array sensor, the surface array image sensor can obtain the two-dimensional light signal space and intensity information, so that the detected light signal center space and intensity information after the dispersion of the light source to be measured are more accurate. In addition, the surface array image sensor also has the advantages of fast transmission speed, low noise, and a large dynamic response range.

[0038] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A micro grating spectrometer, characterized in that: include: A housing (1), wherein the housing (1) is provided with a penetrating light inlet (11); A light homogenizer (2), the light homogenizer (2) being fixedly connected to the inner side of the housing (1), and the light homogenizer (2) covering the light entrance (11); A first light blocking plate (4) is arranged on a side of the light homogenizing plate (2) away from the housing (1), the first light blocking plate (4) being provided with a first incident slit (41) penetrating therethrough; a diffraction grating (5), the diffraction grating (5) being arranged on the inner wall of the housing (1) and being on the same optical path as the first incident slit (41); A detection element (6), the detection element (6) being fixed in the housing (1) and arranged facing the diffraction grating (5); a calculation unit (7), the calculation unit (7) being arranged inside or outside the housing (1) and being electrically connected to the detection element (6); The micro-grating spectrometer further comprises a fixing member (3), the fixing member (3) being fixedly connected to a side of the light homogenizing plate (2) away from the light entrance (11), the fixing member (3) being provided with a penetrating light-transmitting hole (33), the first light-blocking plate (4) being arranged on a side of the light-transmitting hole (33), and the projection of the light-transmitting hole (33) on the first light-blocking plate (4) covering the first incident slit (41); a second light-blocking plate (8) being provided on a side of the fixing member (3) away from the light homogenizing plate (2), the second light-blocking plate (8) being provided with a penetrating second incident slit (81), and the projection of the light-transmitting hole (33) on the second light-blocking plate (8) covering the second incident slit (81); The width of the first incident slit (41) and the second incident slit (81) is 50-1000 µm, and the distance between the first incident slit (41) and the second incident slit (81) is 100-3000 µm; The detection element (6) is a detector module or an image sensor group; the image sensor group adopts a CMOS area array image sensor with a field of view of 40-150°, a focal length of 2-5 mm, and an effective pixel array of 1-1920H×1-1080V.

2. A micro grating spectrometer as claimed in claim 1, characterized in that: A first groove (31) is provided on a surface of the fixing member (3) close to the light homogenizing plate (2), and the first light blocking plate (4) is embedded in the first groove (31); a second groove (32) is provided on a surface of the fixing member (3) away from the light homogenizing plate (2), and the second light blocking plate (8) is embedded in the second groove (32); and the light-transmitting hole (33) passes through the first groove (31) and the second groove (32).

3. A micro grating spectrometer as claimed in claim 1, characterized in that: The light entrance (11), the first incident slit (41), and the second incident slit (81) are arranged in the same plane, and an angle formed by a line connecting the second incident slit (81) and the center point of the diffraction grating (5) and a line connecting the center point of the diffraction grating (5) and the detection element (6) is 30-150°.

4. A micro grating spectrometer as claimed in claim 1, characterized in that: The size of the light homogenizing sheet (2) is 1-80 mm.

5. A micro grating spectrometer as claimed in claim 1, characterized in that: The diffraction grating (5) is a plane reflection grating or a concave reflection grating.

6. A micro grating spectrometer as claimed in claim 5, characterized in that: The plane reflection grating has a length of 2-50 mm, a width of 2-50 mm, a height of 2-50 mm, a spectral range of 300-1100 nm, and a number of engraved lines of 500-2000. The plane reflection grating and the second incident slit (81) are on the same optical path and have an inclination angle of 10-80°.

7. A micro grating spectrometer as claimed in claim 1, characterized in that: The shell (1) has a length of 10-80 mm, a width of 10-80 mm, and a height of 10-80 mm.

Images