Spectrometer and spectrum detection system

Abstract

The embodiment of the invention discloses a spectrograph and a spectrum detection system, which are used for reducing the installation, adjustment and processing complexity of the spectrograph. The spectrometer provided by the embodiment of the invention comprises an input unit, a collimating mirror, a dispersion unit and a single-point detector. The input unit is used for receiving an input optical signal of the spectrometer. The collimating mirror is connected with the input unit and is used for collimating the input optical signal and projecting the collimated input optical signal to the dispersion unit. The dispersion unit is used for carrying out dispersion on the collimated input optical signals to obtain to-be-measured optical signals with multiple wavelengths, changing the emergent directions of the to-be-measured optical signals with the multiple wavelengths, and projecting target to-be-measured optical signals with target wavelengths in the to-be-measured optical signals with the multiple wavelengths to the single-point detector. The single-point detector is used for detecting a target optical signal to be detected.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of spectral analysis, and in particular to a spectrometer and a spectral detection system. Background Art

[0002] Spectral analysis technology is a technology that uses the spectrum of a substance to identify the substance and determine the chemical composition and relative content of the substance. Spectral analysis technology has the advantages of being sensitive, rapid, and non-destructive, and is widely used in food safety, water quality analysis, biomedicine and other fields.

[0003] The optical path structure of current spectrometers is mainly the Chenier-Turner (CT) optical path structure. The CT optical path structure includes two concave reflectors. The two concave reflectors are used for collimation and convergence respectively, so as to project spectral signals of different wavelengths to the detector of the spectrometer to realize spectral detection and analysis.

[0004] In the optical path structure of CT, in order to project the light beam onto the detector, whether it is a collimating mirror or a converging mirror, the focus of the concave mirror needs to be aligned to the preset light beam axis. The focus alignment requirement leads to high installation accuracy requirements for components such as concave mirrors in the spectrometer, making the assembly and processing of the spectrometer more complicated. Summary of the invention

[0005] The embodiments of the present application provide a spectrometer and a spectrum detection system, which are used to reduce the complexity of assembly and processing of the spectrometer.

[0006] In a first aspect, an embodiment of the present application provides a spectrometer. The spectrometer includes: an input unit, a collimator, a dispersion unit and a single-point detector. The input unit is used to receive an input optical signal of the spectrometer. The collimator is connected to the input unit, and is used to collimate the input optical signal, and project the collimated input optical signal to the dispersion unit. The dispersion unit is used to disperse the collimated input optical signal to obtain a plurality of wavelengths of optical signals to be measured, and change the emission direction of the plurality of wavelengths of optical signals to be measured, and project a target optical signal to be measured of a target wavelength among the plurality of wavelengths of optical signals to be measured to the single-point detector. The single-point detector is used to detect the target optical signal to be measured.

[0007] In an embodiment of the present application, the collimator is directly connected to the input unit, and after the input light signal enters the spectrometer from the input unit, it enters the collimator before it has time to diverge, thereby avoiding the amplification of the focus offset caused by the divergence of the light beam. Compared with the light path that first diverges and then collimates in the CT optical path structure, the position deviation between the position of the focus of the collimator in the embodiment of the present application and the optical axis of the input unit will not be amplified due to the divergence of the light beam. Therefore, the influence of the deviation of the installation position (of components such as the input unit and the collimator) on the position overlap (between the focus and the optical axis) can be reduced, thereby reducing the requirements for the installation accuracy of the components on the spectrometer and reducing the complexity of the assembly and processing of the spectrometer.

[0008] In addition, the collimator is connected to the input unit, so that the spot of the signal to be measured inside the spectrometer becomes smaller. On the one hand, reducing the spot can reduce the optical path required for light beams of different wavelengths to separate from each other after the dispersion unit, so there is no need to use a converging concave mirror to reduce the optical path, avoiding the high precision requirements caused by the need to align the focus of the converging concave mirror with the optical axis. This reduces the requirements for the installation accuracy of the components on the spectrometer and reduces the complexity of the assembly and processing of the spectrometer. On the other hand, reducing the spot can reduce the distance between the dispersion unit and the single-point detector, thereby reducing the equipment volume of the spectrometer.

[0009] In an optional implementation, the spectrometer further includes at least one plane reflector. The at least one plane reflector is located on the optical path between the dispersion unit and the single point detector. The target optical signal to be measured from the dispersion unit is projected to the single point detector via the at least one plane reflector.

[0010] In the embodiment of the present application, the optical path between the dispersion unit and the single-point detector is increased by a plane reflector located on the optical path between the dispersion unit and the single-point detector. On the one hand, increasing the optical path can increase the distance between the light spots of the optical signals to be measured of different wavelengths, thereby increasing the number of light beams dispersed by the dispersion unit (see Figure 4a , can be obtained from Figure 4a The three wavelengths of light beams shown in the figure are increased to more light beams), thereby improving the resolution of the spectrometer. On the other hand, when other conditions remain unchanged, increasing the optical path can reduce the distance between the dispersion unit and the single-point detector, thereby reducing the device volume of the entire spectrometer.

[0011] In an optional implementation, the spectrometer further comprises a first substrate, and the number of the reflectors in the at least one plane reflector is greater than or equal to two. The first substrate is used to carry the dispersion unit and the first plane reflector in the at least one plane reflector.

[0012] In the embodiment of the present application, the first substrate is used as the substrate to realize the assembly between the dispersion unit and the first plane reflector, which simplifies the assembly process and reduces the difficulty of assembly.

[0013] Optionally, in a static state, the target surface of the dispersion unit can be parallel to the first plane reflector. The target surface is a plane where the optical signals to be measured of multiple wavelengths are dispersed. Making the two planes parallel can reduce the complexity of the optical path design.

[0014] In an optional implementation, the spectrometer further comprises a second substrate on which a collimating mirror and a second plane reflector of at least one plane reflector are mounted, wherein an angle between a reflective surface of the first plane reflector and a reflective surface of the second plane reflector is less than or equal to 30°.

[0015] In the embodiment of the present application, the angle between the reflection surface of the second plane mirror and the reflection surface of the first plane mirror is made less than or equal to 30°, so that the optical path can be folded, thereby reducing the volume of the spectrometer. In addition, the second plane reflector and the collimator are integrated on the second substrate, and the positions of the second plane reflector and the collimator can be marked in advance on the second substrate, reducing the difficulty of assembly.

[0016] In an optional implementation, the dispersion unit includes a dispersion element, a rotating shaft, a fixed structure and a driving structure. The dispersion element is used to disperse the collimated input optical signal to obtain optical signals to be measured of multiple wavelengths. The rotating shaft is fixedly connected to the dispersion element and movably connected to the fixed structure. The driving structure is used to drive the dispersion element to rotate.

[0017] In an optional implementation, the center of gravity of the rotating shaft is offset from the rotation centerline of the rotating shaft.

[0018] In an embodiment of the present application, the center of gravity of the rotating shaft is deviated from the rotation center line of the rotating shaft, which will generate a torque in a certain direction on the rotation center line (for example, if the center of gravity is located on the right side of the rotation center line, the torque is a clockwise torque). This torque is used to achieve pre-deflection of the dispersion element, making the dispersion element easier to vibrate.

[0019] In an optional implementation, the dispersion unit further comprises a thin film. The thin film is grown on a target surface of the rotating shaft, the target surface is oriented in the same direction as the dispersion surface of the dispersion element, and the geometric center of the thin film is offset from the rotation centerline of the rotating shaft.

[0020] Since the film is obtained on the rotating shaft through a growth process, and the growth process requires a high temperature environment, residual stress will be generated between the film and the rotating shaft. The residual stress of the film acts on the bonding surface between the film and the rotating shaft, and from the bonding surface toward the rotating shaft. The film grown on the target surface of the rotating shaft, and the geometric center is offset from the rotation center line, will generate residual stress on the rotating shaft on the bonding surface. The residual stress will generate a torque in a certain direction on the rotation center line (for example, the film is located on the upper surface of the rotating shaft, and the geometric center of the film is located on the right side of the rotation center line, and the torque is a clockwise torque), thereby realizing the pre-deflection of the dispersion element, making the dispersion element easier to vibrate.

[0021] In the embodiment of the present application, the dispersion surface of the dispersion element is a surface that causes the passing light beam to disperse (for example Fig.10 The upper surface of the reflective grating 3311 is also the grating surface of the reflective grating 3311). The light beam is projected to the dispersion element from a certain direction, and the dispersion surface of the dispersion element disperses and reflects the light beam. The dispersion surface is perpendicular to the dispersion surface and points in the direction of the light beam (for example Fig.10 The light beam is projected from top to bottom onto the dispersion surface, dispersed and reflected by the dispersion surface, and then leaves the dispersion surface from bottom to top. Fig.10 The medium dispersion surface is oriented upward).

[0022] Optionally, the target surface of the rotating shaft can be a plane or a curved surface. If the target surface is a plane, the target surface can optionally be a surface parallel to and facing the dispersion surface. If the target surface is a curved surface (for example, the rotating shaft is a cylinder), the target surface can optionally be a portion of the outer surface (curved surface) of the rotating shaft facing the same direction as the dispersion plane.

[0023] Optionally, the film grown on the rotating shaft may be a metal film or a non-metal film, which is not limited in the present application.

[0024] In an optional implementation, the dispersion unit further comprises a thin film. The thin film is grown on a target surface of the rotating shaft, and the target surface is oriented in the same direction as the dispersion surface of the dispersion element. The geometric center of the thin film and the center of gravity of the rotating shaft are located on the same side of the rotation centerline of the rotating shaft.

[0025] In the embodiment of the present application, the geometric center of the film and the center of gravity of the shaft are located on the same side of the rotation centerline of the shaft, and the direction of the torque generated on the rotation centerline by the center of gravity of the shaft is the same as the direction of the torque generated on the rotation centerline by the residual stress of the film. The superposition of the two torques can make the dispersion element easier to vibrate.

[0026] Optionally, if the center of gravity of the shaft is located on the right side of the rotation centerline, the gravity of the shaft will provide a clockwise torque to the shaft. In order to strengthen the torque in this direction, in addition to growing a film on the target surface of the shaft, a film can also be grown on other surfaces of the shaft to provide a clockwise torque to the shaft through the residual stress of the film. For example, assuming that the target surface is the surface with the shaft facing upward; if a film is grown on the surface with the shaft facing downward, the geometric center of the film can be located on the left side of the rotation centerline; if a film is grown on the surface with the shaft facing right, the geometric center of the film can be located on the lower side of the rotation centerline; if a film is grown on the surface with the shaft facing left, the geometric center of the film can be located on the upper side of the rotation centerline.

[0027] It is worth noting that the number of films is not limited in the embodiments of the present application, and one or more films can be grown on the rotating shaft. If multiple films are grown, the torques generated by the multiple films on the rotating shaft should be in the same direction.

[0028] Similarly, if the center of gravity of the shaft is located to the left of the rotation centerline, the gravity of the shaft will provide a counterclockwise torque to the shaft. The counterclockwise torque can also be enhanced by growing a film on the shaft.

[0029] In an optional implementation, the dispersive element includes a reflective grating or a metasurface structure.

[0030] In an optional implementation, the input unit includes an incident optical fiber. The input end of the incident optical fiber is used to receive an input optical signal, and the output end of the incident optical fiber is connected to the collimator. In this structure, the incident optical fiber is directly connected to the collimator, and the optical signal can directly enter the collimator from the incident optical fiber.

[0031] In an embodiment of the present application, the incident optical fiber and the collimator can be processed in an integrated manner (the two can be processed in an integrated manner into an optical fiber with a microlens), and the focus of the collimator can be ensured to be on the optical axis of the incident optical fiber during the integrated processing. Therefore, there is no need to consider the alignment of the focus to the optical axis in terms of collimation, which reduces the installation accuracy requirements of the components on the spectrometer. In this structure, the input light signal of the spectrometer enters the optical fiber with a microlens, and is transmitted to the microlens directly connected to the optical fiber, thereby being collimated by the microlens. The light beam is collimated before it has time to diverge, and the collimated light spot is small.

[0032] In an optional implementation, the input unit includes a coupling unit. The coupling unit is used to receive an input optical signal of the spectrometer and couple the input optical signal to the collimating mirror.

[0033] In the embodiment of the present application, the coupling unit is equivalent to the incident slit in the CT optical path structure, so the range of the light spot on the coupling unit is small, and the actual optical axis position is easier to determine. In addition, the coupling unit is connected to the collimator, so the focus of the collimator is easier to align with the actual optical axis of the input optical signal, reducing the installation accuracy requirements of the device on the collimated optical path (i.e., the optical path of the input optical signal from the input unit to the collimator).

[0034] In an optional implementation, the collimating lens includes a microlens or a lens.

[0035] In a second aspect, an embodiment of the present application provides a spectrum detection system. The spectrum detection system includes a light source and the spectrometer described in the first aspect. The light source is used to illuminate the substance to be measured to obtain an input light signal of the spectrometer. The spectrometer is used to receive and detect the input light signal.

[0036] The beneficial effects of the second aspect refer to the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of the structure of the spectrum detection system provided in this application;

[0038] Figure 2 A schematic diagram of the CT optical path structure provided for this application;

[0039] Figure 3 A schematic diagram of the structure of a spectrometer provided in an embodiment of the present application;

[0040] Figure 4a A schematic diagram of reducing the light spot to achieve a reduction in optical path provided in an embodiment of the present application;

[0041] Figure 4b A schematic diagram of the light beam of the CT optical path structure provided in this application;

[0042] Figure 5 A schematic structural diagram of a spectrometer including a plane reflector provided in an embodiment of the present application;

[0043] Figure 6 A schematic structural diagram of a spectrometer including a first substrate provided in an embodiment of the present application;

[0044] Figure 7 A schematic diagram of the structure of a dispersion unit provided in an embodiment of the present application;

[0045] Figure 8 Another schematic diagram of the structure of the dispersion unit provided in the embodiment of the present application;

[0046] Fig. 9 A schematic diagram of the structure of a spectrometer with a replaceable single-point detector provided in an embodiment of the present application;

[0047] Fig.10 A structural schematic diagram of a MEMS grating scanning mirror provided in an embodiment of the present application;

[0048] Fig.11 Another structural schematic diagram of the MEMS grating scanning mirror provided in an embodiment of the present application;

[0049] Fig.12 A schematic diagram of the thin film growth position provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] The embodiments of the present application are described below in conjunction with the accompanying drawings. Those skilled in the art will appreciate that, with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0051] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged in appropriate circumstances, which is only to describe the distinction mode adopted by the objects of the same attribute in the embodiments of the present application when describing. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment containing a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment. In addition, "at least one" refers to one or more, and "multiple" refers to two or more. "And / or", describes the association relationship of associated objects, indicating that three relationships can exist, for example, A and / or B, can represent: A exists alone, A and B exist simultaneously, and B exists alone, wherein A, B can be singular or plural. The character " / " generally represents that the associated objects before and after are a kind of "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0052] Since each substance has its own characteristic spectrum, the spectrum can be used to identify the substance and determine its chemical composition, relative content, etc. This analysis method is called spectral analysis technology. Spectral analysis technology has the advantages of being sensitive, rapid, and non-destructive, and is widely used in food safety, water quality analysis, biomedicine and other fields.

[0053] Figure 1 This is a schematic diagram of the structure of the spectrum detection system provided in this application. Figure 1 As shown, the spectrum detection system includes a light source and a spectrometer. The light source is used to emit a light beam, and the light beam emitted by the light source is irradiated onto the substance to be tested (such as liquid, gas, etc.) to obtain an input light signal of the spectrometer. The spectrometer is used to obtain the spectrum of the input light signal, thereby obtaining the spectrum of the substance to be tested.

[0054] like Figure 2 As shown, a traditional spectrometer includes components such as an incident slit, a collimating concave mirror, a grating, a concave concave mirror and a detector. The input light signal is input into the spectrometer from the incident slit and projected onto the collimating concave mirror. The collimating concave mirror collimates the input light signal and projects it onto the grating. The grating disperses the collimated input light signal to obtain light signals of different wavelengths. After being projected onto the concave concave mirror, the light signals of different wavelengths are converged to the detector by the concave concave mirror. There is a slit in front of the detector. By rotating the grating, the exit angle of the light signal from the grating can be changed, thereby changing the light signal passing through the slit. For example Figure 2 The wavelengths of the light beams projected onto the detector are λ1 to λ3 from left to right. Figure 2 The state of the light beam is λ2 and projected onto the detector. By rotating the grating, the light beam of λ1 or λ3 can be projected onto the detector. Thus, the detector can detect light signals of different wavelengths and obtain the spectrum of the input light signal, that is, the spectrum of the substance to be tested.

[0055] This optical path structure that first aligns the divergent light signal to the grating for dispersion, and then converges the dispersed light signals of different wavelengths onto the detector is called a CT optical path structure. In the CT optical path structure, in order to ensure that the divergence angle of the light beam is small when it is incident on the grating, it is necessary to ensure the collimation effect, and it is necessary to ensure that the focus of the collimating concave mirror is on the optical axis of the light beam; in order to ensure that the light signals of each wavelength can be received by the detector, it is necessary to ensure that the focus of the converging concave mirror is on the optical axis of the light beam.

[0056] The design and manufacture of the spectrometer includes steps such as optical axis design, device position design and device installation. From the above, it can be seen that after the installation of the various devices in the spectrometer is completed, the focus of the collimating concave mirror should be on the actual optical axis of the light beam, and the focus of the converging concave mirror should be on the actual optical axis of the light beam.

[0057] However, there may be a certain deviation between the actual installation position of each component in the spectrometer and the preset installation position, resulting in a certain deviation between the actual optical axis of the light beam and the preset optical axis of the light beam. There may also be a certain deviation between the actual installation position of the collimating concave mirror and the converging concave mirror and the preset installation position, resulting in a certain deviation between the actual focal position and the preset focal position. The combination of these two factors makes it difficult to align the focus of the collimating concave mirror and the focus of the converging concave mirror to the actual optical axis. Currently, the alignment of the focus to the optical axis can only be achieved by improving the installation accuracy of each component. This leads to high requirements for the installation accuracy of the components in the spectrometer, making the assembly and processing of the spectrometer more complicated.

[0058] In addition, the structure of the double concave mirror of the CT optical path structure results in a large volume of the spectrometer. The large device structure cannot meet the demand for the development of spectrometers towards miniaturization and lightness.

[0059] In order to solve the above problems, the embodiments of the present application provide a spectrometer and a spectrum detection system. The spectrometer provided in the embodiments of the present application realizes collimation through a transmission collimator connected to the incident slit, which reduces the difficulty of focus alignment of the collimator on the one hand, and reduces the spot size on the other hand, so that there is no need to converge light beams of different wavelengths, thus eliminating the need for convergent focus alignment. The spectrometer provided in the embodiments of the present application can reduce the installation accuracy requirements of the components in the spectrometer, thereby reducing the complexity of the assembly and processing of the spectrometer.

[0060] like Figure 3 As shown, the spectrometer 3000 provided in the embodiment of the present application includes: an input unit 3100, a collimator 3200, a dispersion unit 3300 and a single point detector 3400. The input unit 3100 is used to receive an input optical signal of the spectrometer 3000. The collimator 3200 is connected to the input unit 3100 and is used to collimate the input optical signal.

[0061] For example, the input unit 3100 and the collimator 3200 may be directly connected, or the distance between the two may be very close. In this structure, the optical path of the light beam between the input unit 3100 and the collimator 3200 is very small, and the light beam does not diverge or the degree of divergence is very small.

[0062] In the embodiment of the present application, the collimator 3200 is connected to the input unit 3100. After the input light signal enters the spectrometer 3000 from the input unit 3100, it enters the collimator 3200 before it has time to diverge, thereby avoiding the amplification of the focus offset by the divergence of the light beam. Compared with the light path that first diverges and then collimates in the CT optical path structure, the position deviation between the position of the focus of the collimator 3200 and the optical axis of the input unit 3100 in the embodiment of the present application will not be amplified due to the divergence of the light beam. Therefore, the influence of the deviation of the installation position (of the input unit 3100, the collimator 3200 and other devices) on the position overlap (between the focus and the optical axis) can be reduced, thereby reducing the requirements for the installation accuracy of the devices on the spectrometer 3000 and reducing the complexity of the assembly and processing of the spectrometer 3000.

[0063] In the embodiment of the present application, the input optical signal of the spectrometer obtained after the light beam passes through the substance to be measured can enter the spectrometer in different ways. Optionally, the input optical signal can be input into the spectrometer through optical fiber or spatial optical coupling. Correspondingly, the input unit 3100 of the spectrometer 3000 can be an incident optical fiber, a coupling unit, etc., which is not limited in the present application.

[0064] If the input optical signal is input to the spectrometer 3000 through an optical fiber, the input unit 3100 is an incident optical fiber. The input end of the incident optical fiber is used to receive the input optical signal, and the output end is used to connect to the collimator 3200. Optionally, the incident optical fiber and the collimator 3200 can be integrated, and the focus of the collimator 3200 can be ensured on the optical axis of the incident optical fiber during the integrated processing. Therefore, there is no need to consider the alignment of the focus to the optical axis in terms of collimation, which reduces the installation accuracy requirements of the components on the spectrometer 3000.

[0065] For example, the collimator 3200 can be a microlens (also called a microlens), and the incident optical fiber and the microlens can be integrated into an optical fiber with a microlens, or the optical fiber with a microlens can be directly used as a raw material during the processing, thereby reducing the installation accuracy requirements of the components on the spectrometer 3000. In this structure, the input optical signal of the spectrometer 3000 enters the optical fiber with a microlens, and is transmitted to the microlens directly connected to the optical fiber, and is collimated by the microlens. The light beam is collimated before it has time to diverge, and the collimated light spot is small.

[0066] If the input optical signal is input to the spectrometer 3000 through spatial optical coupling, the input unit 3100 is a coupling unit. The coupling unit can be a lens, a lens group, a prism, etc., which is not limited in this application. The coupling unit is used to receive the input optical signal of the spectrometer 3000 and couple the input optical signal to the collimator 3200. The coupling unit is equivalent to the incident slit in the CT optical path structure, so the range of the light spot on the coupling unit is small, and the actual optical axis position is easier to determine. And the coupling unit is connected to the collimator 3200, so the focus of the collimator 3200 is easier to align to the actual optical axis of the input optical signal, reducing the installation accuracy requirements of the device on the collimated optical path (i.e., the optical path of the input optical signal from the input unit 3100 to the collimator 3200).

[0067] In the embodiment of the present application, the collimator 3200 is a transmissive collimator. Optionally, the collimator 3200 may be a microlens, a lens, etc., which is not limited in the present application.

[0068] After the input optical signal is collimated, the collimator 3200 is further used to project the collimated input optical signal to the dispersion unit 3300. The dispersion unit 3300 is used to disperse the collimated input optical signal to obtain optical signals to be measured of multiple wavelengths.

[0069] In order to obtain the spectrum of the substance to be measured, the spectrometer 3000 needs to detect the optical signals to be measured of the multiple wavelengths one by one to obtain the light intensities of the optical signals to be measured of different wavelengths. Therefore, it is necessary to project the optical signals to be measured of different wavelengths to the single point detector 3400 at different times. The embodiment of the present application adjusts the wavelength of the optical signal to be measured projected to the single point detector 3400 through the dispersion unit 3300.

[0070] Specifically, the dispersion unit 3300 can change the emission direction of the optical signals to be measured of multiple wavelengths, and project the target optical signal to be measured of the target wavelength (among the optical signals to be measured of the multiple wavelengths) to the single point detector 3400. The single point detector 3400 is used to detect the target optical signal to be measured. Optionally, the dispersion unit 3300 may include a microelectromechanical system (MEMS) grating scanning mirror, a metasurface structure, etc., which is not limited in the present application.

[0071] For example, the default position of the spectrometer 3000 at the initial moment is as follows: Figure 3As shown, at this time, the second optical signal to be measured with a wavelength of λ2 is projected onto the single-point detector 3400. If it is desired to detect the first optical signal to be measured with a wavelength of λ1 at the first moment, and to detect the third optical signal to be measured with a wavelength of λ3 at the second moment, the dispersion unit 3300 rotates the emission directions of the optical signals to be measured with multiple wavelengths counterclockwise by β-α at the first moment (compared to the initial position), so that the first optical signal to be measured with a wavelength of λ1 is projected onto the single-point detector 3400; and rotates the emission directions of the optical signals to be measured with multiple wavelengths clockwise by γ-β at the second moment (compared to the initial position), so that the third optical signal to be measured with a wavelength of λ3 is projected onto the single-point detector 3400.

[0072] In the embodiment of the present application, after the incident light signal enters the spectrometer 3000, it is collimated by the collimator 3200 without being diverged. Therefore, compared with the existing CT optical path structure, the collimated light beam in the embodiment of the present application has a smaller spot size. Figure 4a As shown, the grating has the same dispersion angle (i.e. the angle between light signals of different wavelengths, e.g. Figure 4a The collimated optical signal is dispersed into optical signals from λ1 to λ3. Since the light spot in the CT optical path structure is large, after leaving the grating, signals of different wavelengths need to go through a long optical path so that they will not overlap with each other. This results in a large optical path structure. Therefore, a converging concave mirror is set in the CT optical path to reduce the divergence angle of the light beam (such as Figure 4b As shown), the optical path is reduced and the size of the equipment is reduced.

[0073] In the optical path structure of the embodiment of the present application, since the light spot is small, after leaving the grating, the optical signals to be measured of different wavelengths will not overlap with each other after a shorter optical path, so there is no need to set a concave concave mirror to reduce the dispersion angle of the light beam and shorten the optical path.

[0074] Therefore, the structure of the spectrometer 3000 provided in the embodiment of the present application makes the spot of the signal to be measured inside the spectrometer 3000 smaller. On the one hand, reducing the spot can reduce the optical path required for light beams of different wavelengths to separate from each other after the dispersion unit 3300, so that there is no need to use a converging concave mirror to reduce the optical path, avoiding the problem of high precision requirements caused by the need to align the focus of the converging concave mirror with the optical axis. On the other hand, the reduction of the spot can reduce the distance between the grating (dispersion unit 3300) and the detector (single point detector 3400), thereby reducing the device volume of the spectrometer.

[0075] Optionally, the spectrometer 3000 provided in the embodiment of the present application may further be provided with one or more plane reflectors 3500 on the optical path between the dispersion unit 3300 and the single-point detector 3400 to increase the optical path length of the optical signals to be measured of different wavelengths.

[0076] like Figure 5 As shown, the spectrometer 3000 further includes a plane reflector 3500-1 and a plane reflector 3500-2. The plane reflector 3500-1 and the plane reflector 3500-2 are both located on the optical path between the dispersion unit 3300 and the single point detector 3400. The target optical signal to be measured from the dispersion unit 3300 is projected to the single point detector 3400 after passing through the plane reflector 3500-1 and the plane reflector 3500-2.

[0077] In the embodiment of the present application, the optical path between the dispersion unit 3300 and the single point detector 3400 is increased by a plane reflector located on the optical path between the dispersion unit 3300 and the single point detector 3400. On the one hand, increasing the optical path can increase the distance between the light spots of the optical signals to be measured of different wavelengths, thereby increasing the number of light beams dispersed by the dispersion unit 3300 (see Figure 4a , can be obtained from Figure 4a The three wavelengths of light beams shown in the figure are increased to more light beams), thereby improving the resolution of the spectrometer 3000. On the other hand, when other conditions remain unchanged, increasing the optical path can reduce the distance between the dispersion unit 3300 and the single-point detector 3400, thereby reducing the device volume of the entire spectrometer 3000.

[0078] It is worth noting that Figure 5 The embodiment shown is only an example and does not limit the number of plane reflectors. The number of plane reflectors included in the spectrometer 3000 may also be one, three or more, which is not limited in the present application.

[0079] Optionally, if the number of the plane mirrors 3500 is greater than or equal to 2, the dispersion unit 3300 and some of the plane mirrors may be integrated on one substrate to simplify the assembly process.

[0080] like Figure 6 As shown, the spectrometer 3000 further includes a first substrate 3600. The first substrate 3600 is used to carry the dispersion unit 3300 and the plane reflector 3500-2. In the embodiment of the present application, the plane reflector 3500 located on the first substrate 3600 is called a first plane reflector, and the first plane reflector is parallel to the target surface of the dispersion unit 3300.

[0081] In the embodiment of the present application, the first substrate 3600 is used as a substrate to realize the assembly between the dispersion unit 3300 and the first plane reflector, which simplifies the assembly process and reduces the difficulty of assembly.

[0082] Optionally, in a static state, the target surface of the dispersion unit 3300 can be parallel to the plane reflector. The target surface is a plane where the optical signals to be measured of multiple wavelengths are dispersed. If the dispersion unit 3300 is a grating, the target surface is a grating surface. By making the two planes parallel, the complexity of the optical path design can be reduced.

[0083] The following uses the MEMS grating scanning mirror 3310 as an example of the dispersion unit 3300 to illustrate the specific connection method of the first substrate 3600, the dispersion unit 3300 and the first plane reflector.

[0084] Optional, such as Figure 7 As shown, the MEMS grating scanning mirror 3310 is independent from the first substrate 3600, and the first plane reflector is also independent from the first substrate 3600. The MEMS grating scanning mirror 3310 and the first plane reflector can be fixed on the first substrate 3600 by mounting, gluing, welding, bonding, etc.

[0085] Optional, such as Figure 8 As shown, the MEMS grating scanning mirror 3310 and the first plane reflecting mirror can also be processed in an integrated manner with the first substrate 3600. That is, the first substrate 3600 is directly used as a substrate, and the MEMS grating scanning mirror 3310 and the first plane reflecting mirror are prepared on the first substrate 3600 through various semiconductor preparation processes. Integrated processing can simplify the processing flow and reduce the difficulty of assembly.

[0086] Optional, such as Figure 6 As shown, the spectrometer 3000 may further include a second substrate 3700. A collimator 3200 and a plane reflector 3500-1 are mounted on the second substrate 3700. In the embodiment of the present application, the plane reflector located on the second substrate 3700 is referred to as a second plane reflector. The angle between the reflective surface of the first plane mirror (e.g., plane reflector 3500-2) and the reflective surface of the second plane reflector (e.g., plane reflector 3500-1) is less than or equal to 30°.

[0087] If the angle between the reflection surfaces of the two plane mirrors is greater than 30°, the path of the light beam will become flatter and flatter after being reflected by the two plane mirrors, resulting in the overall length of the spectrometer 3000 being very long. Figure 6 For example, if the left end of the second substrate 3700 is higher than the right end, so that there is an angle toward the left between the reflection surfaces of the plane reflector 3500-1 and the plane reflector 3500-2, then after the light beam is dispersed by the dispersion unit 3300, the incident angle projected onto the plane reflector 3500-1 is smaller than Figure 6will be larger, and the corresponding exit angle on the plane reflector 3500-2 will also be larger. The light beam is reflected by the plane reflector 3500-1 to the plane reflector 3500-2. The position of the plane reflector 3500-2 is relatively Figure 6 The incident angle of the light beam incident on the plane reflector 3500-2 is more to the left than Figure 6 As shown, the angle of incidence increases, and the position of the single-point detector 3400 is also based on Figure 6 Moving to the left makes the entire spectrometer longer and larger.

[0088] by Figure 6 For example, if the left end of the second substrate 3700 is moved downward so that the right end of the second substrate 3700 is higher than the left end, there is an angle between the reflection surfaces of the plane reflector 3500-1 and the plane reflector 3500-2 that faces the right side. In order to ensure the resolution of the spectrometer, it is necessary to ensure that the optical path from the dispersion unit 3300 to the single point detector 3400 is equal to Figure 6 If the optical path shown is consistent, the dispersion unit 3300, the input unit 3100 and the collimating lens 3200 need to be moved to the right as a whole, so that the entire spectrometer becomes longer and the volume increases.

[0089] Therefore, in the embodiment of the present application, the angle between the second plane mirror and the first plane mirror is less than or equal to 30°, so that the optical path can be fully folded, thereby reducing the volume of the spectrometer 3000. In addition, the second plane reflector and the collimator 3200 are integrated on the second substrate 3700, and the positions of the second plane reflector and the collimator 3200 can be marked in advance on the second substrate 3700, thereby reducing the difficulty of assembly.

[0090] Optionally, the single point detector 3400 may also be integrated on the second substrate 3700. For example Fig. 9 As shown, a hole may be reserved on the second substrate for installing a single point detector 3400. By replacing different single point detectors 3400, the sensitivity of the spectrometer 3000 may be adjusted.

[0091] In the embodiment of the present application, the dispersion unit 3300 can be a MEMS grating scanning mirror, a metasurface structure, etc., and the present application does not limit this.

[0092] like Fig.10As shown, if the dispersion unit 3300 is a MEMS grating scanning mirror 3310, the MEMS grating scanning mirror 3310 includes a reflective grating 3311, a rotating shaft 3312, a fixed structure 3313 and a driving structure 3314. The reflective grating 3311 is used to disperse the input optical signal after alignment to obtain optical signals to be measured of multiple wavelengths. The rotating shaft 3312 is fixedly connected to the reflective grating 3311 and movably connected to the fixed structure 3313. The driving structure 3314 is used to drive the reflective grating 3311 to rotate along the rotation center line, so that the optical signals to be measured of multiple wavelengths rotate along the rotation center line, thereby projecting the target optical signal to be measured to the single point detector 3400.

[0093] The rotation center line is a straight line passing through the rotating shaft 3312. The rotating shaft 3312 is usually a cylinder, etc., and the rotation center line is the axis of the cylindrical rotating shaft 3312. If the rotating shaft 3312 is another shape, the rotation center line corresponds to the axis of the shape. Fig.10 In the structure shown, the rotation center line is in the y-axis direction, located on the grating plane of the reflective grating 3311 , and passes through the rotation axis 3312 .

[0094] Optionally, the driving structure 3314 may be an electrostatic comb, an electromagnetic coil, a piezoelectric film, etc., which is not limited in the present application.

[0095] Optionally, the embodiment of the present application can realize pre-deflection of the reflective grating 3311 through some special structural designs, so that the reflective grating 3311 is easier to vibrate. These structural designs include but are not limited to center of gravity offset, residual stress of the film, etc., which will be described separately below.

[0096] For example Fig.11 As shown, the rotating shaft 3312 can be set as a prism extending along the y-axis direction, and the rotation center line is the axis of the rotating shaft 3312 (the axis is at the same distance from the leftmost and rightmost sides of the rotating shaft). A shallow groove can be dug on the left side of the rotating shaft 3312 (the three-dimensional structure is as shown in FIG. Fig.10 As shown in FIG. 3 ), the center of gravity of the rotating shaft 3312 is located on the right side of the rotation center line. Fig.11 As shown, the gravity on the right side of the rotating shaft 3312 can provide a clockwise torque for the rotating shaft 3312, making it easier for the reflective grating 3311 to vibrate.

[0097] In the embodiment of the present application, the center of gravity of the rotating shaft 3312 is offset from the rotation center line of the rotating shaft 3312. The deviation of the center of gravity of the rotating shaft 3312 from the rotation center line will generate a torque in a certain direction (for example, clockwise) on the rotation center line. The torque is used to achieve pre-deflection of the reflective grating 3311, making it easier for the reflective grating 3311 to oscillate.

[0098] Similarly, a shallow groove can be dug on the right side of the rotating shaft 3312 so that the center of gravity is offset to the left side of the rotation centerline. The gravity of the rotating shaft 3312 on the left side can provide a counterclockwise torque for the rotating shaft 3312. The present application does not limit this. Optionally, the density distribution in the rotating shaft 3312 can also be changed so that the center of gravity of the rotating shaft 3312 is offset to the left or right side of the rotation centerline.

[0099] For example Fig.11 As shown, a thin film can also be grown on the target surface of the rotating shaft 3312, and the geometric center of the thin film is offset from the rotation center line. The target surface of the rotating shaft 3312 is oriented in the same direction as the dispersion surface of the reflective grating 3311. Since the thin film is obtained on the rotating shaft 3312 through a growth process, and the growth process requires a high temperature environment, residual stress will be generated between the thin film and the rotating shaft 3312. The residual stress of the thin film acts on the bonding surface between the thin film and the rotating shaft 3312, and from the bonding surface toward the rotating shaft 3312. A thin film grown on the target surface of the rotating shaft 3312, with its geometric center offset from the rotation center line (for example Fig.11 The film in the middle is located on the right side of the rotation centerline), which will generate residual stress on the rotation shaft 3312 on the bonding surface. The residual stress will generate a torque in a certain direction on the rotation centerline (for example Fig.11 As shown, the film is located on the upper surface of the rotating shaft 3312, and the geometric center of the film is located on the right side of the rotation center line, and the torque is the clockwise torque), thereby realizing the pre-deflection of the reflective grating 3311, making the reflective grating 3311 easier to oscillate.

[0100] In the embodiment of the present application, the dispersion surface of the reflective grating 3311 is a surface that causes the passing light beam to disperse (for example Fig.10 The upper surface of the reflective grating 3311 is also the grating surface of the reflective grating 3311, which is the xOy plane in the coordinate system). The light beam is projected to the reflective grating 3311 from a certain direction, and the dispersion surface of the reflective grating 3311 disperses and reflects the light beam. The dispersion surface is perpendicular to the dispersion surface and points in the direction of the light beam (for example Fig.10 The light beam is projected from top to bottom onto the dispersion surface, dispersed and reflected by the dispersion surface, and then leaves the dispersion surface from bottom to top. Fig.10 The dispersion surface is oriented upward, i.e., pointing to the positive direction of the z-axis). Fig.10 In the example, the target surface of the rotation axis 3312 is a plane of the xOy plane facing the positive direction of the z axis.

[0101] Optionally, the target surface of the rotating shaft can be a plane or a curved surface. If the target surface is a plane, the target surface can optionally be a surface parallel to the dispersion surface and facing the same direction (e.g. Fig.10If the target surface is a curved surface (for example, the rotating shaft is a cylinder), the target surface may be a portion of the outer surface (curved surface) of the rotating shaft 3312 that faces the same direction as the dispersion plane (for example, a portion of the cylindrical surface that faces upward).

[0102] Optionally, the film grown on the rotating shaft may be a metal film or a non-metal film, which is not limited in the present application.

[0103] Optionally, on the rotating shaft 3312, the deviation between the center of gravity and the rotation center line can be set separately, or a film can be set separately, or the center of gravity deviation and the film can be combined to achieve pre-deflection of the reflective grating 3311, and this application does not limit this.

[0104] Optionally, if the center of gravity offset and the residual stress of the film are combined in the same structure, the torque generated by the center of gravity offset of the rotating shaft 3312 should be consistent with the direction of the torque generated by the film stress of the film, so that the effects of the two forces (torques) are superimposed, making it easier for the reflective grating 3311 to vibrate.

[0105] Fig.11 for Fig.10 Schematic diagram of the structure shown on the target surface. Fig.11 As shown in FIG. 1 , the center of gravity of the rotating shaft 3312 is on the right side of the rotation centerline, and the gravity of the rotating shaft 3312 provides a clockwise torque for the rotating shaft 3312. In order to strengthen the torque in this direction, the rotating shaft 3312 can be Fig.11 As shown, a film is grown on the right side of the rotation centerline (the offset with the center of gravity is on the same side of the rotation centerline) on the target surface of the rotation axis 3312. The residual stress of the film is downward, and the residual stress will produce a clockwise rotation axis on the rotation axis 3312.

[0106] In the embodiment of the present application, the geometric center of the film and the center of gravity of the shaft 3312 are located on the same side of the rotation center line of the shaft 3312, and the center of gravity of the shaft 3312 deviates from the direction of the torque generated on the rotation center line, which is the same as the direction of the torque generated on the rotation center line by the residual stress of the film. The superposition of the two torques can make the reflective grating 3311 easier to vibrate.

[0107] Optionally, if it is desired to provide torque to the rotating shaft 3312 by growing a thin film, in addition to Fig.11 The thin film is grown on the target surface of the rotating shaft 3312 as shown, and the thin film can also be grown on other surfaces of the rotating shaft 3312. Fig.12As shown, if you want to obtain a clockwise torque, assume that the target surface is the surface with the rotating shaft 3312 facing upward (i.e., the surface with the xOy plane facing the positive direction of the z-axis); if a certain film grows on the surface with the rotating shaft 3312 facing right, the geometric center of the film can be located below the rotation center line; if a certain film grows on the surface with the rotating shaft facing downward, the geometric center of the film can be located on the left side of the rotation center line (if the film is located on the surface of the rotating shaft 3312 facing opposite to the target surface, the center of gravity of the rotating shaft 3312 and the geometric center of the film are located on different sides of the rotation center line); if a certain film grows on the surface with the rotating shaft facing left, the geometric center of the film can be located above the rotation center line. In this way, a clockwise torque can be provided to the rotating shaft 3312 through the residual stress of the film.

[0108] Similarly, if the center of gravity of the rotating shaft 3312 is on the left side of the rotation center line, the gravity of the rotating shaft 3312 provides a counterclockwise torque for the rotating shaft 3312. Then the film can be grown at any of the following positions so that the residual stress of the film provides a counterclockwise torque for the rotating shaft 3312. The film growth positions include: on the upward surface of the rotating shaft 3312 (i.e., the target surface), and the geometric center of the film is on the left side of the rotation center (the center of gravity of the rotating shaft 3312 and the geometric center of the film are on the same side of the rotation center line); on the downward surface of the rotating shaft 3312, and the geometric center of the film is on the right side of the rotation center line; on the right surface of the rotating shaft 3312, and the geometric center of the film is on the upper side of the rotation center line; on the left surface of the rotating shaft 3312, and the geometric center of the film is on the lower side of the rotation center line. It is worth noting that the number of films is not limited in the embodiment of the present application, and one or more films can be grown on the rotating shaft. If multiple films are grown, the torque directions generated by the multiple films on the rotating shaft 3312 should be the same.

[0109] Optionally, in addition to the MEMS grating structure, the dispersion unit 3300 may also be a metasurface structure. Fig.10 and Fig.11 In the structure shown, the reflective grating 3311 serving as a dispersion element is replaced with a metasurface structure to obtain a dispersion unit 3300 including a metasurface structure, which will not be described in detail here.

[0110] Optionally, the signal emission direction of the metasurface structure can also be changed by other means. For example, the metasurface structure can be a dispersion layer, a modulation layer, etc. The metasurface structure is used to modulate the amplitude or phase of the optical signal, thereby changing the emission direction of the optical signals to be measured of multiple wavelengths, and projecting the target optical signal to be measured to a single point detector.

[0111] Will Figures 3 to 11 The spectrometer 3000 shown is used in Figure 1 The system shown is the spectral detection system provided in the embodiment of the present application.

[0112] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0113] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0114] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0115] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0116] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program code.

Claims

1. A spectrometer, characterized in that: include: Input unit, collimator, dispersion unit and single point detector; The input unit is used to receive an input optical signal of the spectrometer; The collimator is connected to the input unit and is used to collimate the input optical signal and project the collimated input optical signal to the dispersion unit; The dispersion unit is used to disperse the collimated input optical signal to obtain optical signals to be measured of multiple wavelengths, change the emission directions of the optical signals to be measured of the multiple wavelengths, and project the target optical signal to be measured of the target wavelength among the optical signals to be measured of the multiple wavelengths to the single point detector; The single-point detector is used to detect the target optical signal to be measured.

2. The spectrometer according to claim 1, characterized in that The spectrometer further comprises at least one plane reflector, wherein the at least one plane reflector is located on an optical path between the dispersion unit and the single point detector; The target optical signal to be measured from the dispersion unit is projected to the single-point detector via the at least one plane reflector.

3. The spectrometer according to claim 2, characterized in that The spectrometer further comprises a first substrate, the number of reflectors in the at least one plane reflector being greater than or equal to two; The first substrate is used to support the dispersion unit and the first plane reflector of the at least one plane reflector.

4. The spectrometer according to claim 3, characterized in that The spectrometer further includes a second substrate on which the collimating mirror and a second plane reflector of the at least one plane reflector are mounted, and an angle between a reflective surface of the first plane reflector and a reflective surface of the second plane reflector is less than or equal to 30°.

5. The spectrometer according to any one of claims 1 to 4, characterized in that: The dispersion unit includes a dispersion element, a rotating shaft, a fixing structure and a driving structure; The dispersion element is used to disperse the collimated input optical signal to obtain optical signals to be measured of multiple wavelengths; The rotating shaft is fixedly connected to the dispersive element and movably connected to the fixed structure; The driving structure is used to drive the dispersive element to rotate.

6. The spectrometer according to claim 5, characterized in that The center of gravity of the rotating shaft is offset from the rotation center line of the rotating shaft.

7. The spectrometer according to claim 5, characterized in that The dispersion unit further comprises a film, which is grown on a target surface of the rotating shaft, wherein a geometric center of the film is offset from a rotation center line of the rotating shaft, and the target surface and a dispersion surface of the dispersion element are oriented in the same direction.

8. The spectrometer according to claim 6, characterized in that: The dispersion unit also includes a film, which is grown on a target surface of the shaft, wherein the geometric center of the film and the center of gravity of the shaft are located on the same side of the rotation centerline of the shaft, and the target surface and the dispersion surface of the dispersion element face the same direction.

9. The spectrometer according to any one of claims 5 to 8, characterized in that The dispersive element includes a reflective grating or a metasurface structure.

10. The spectrometer according to any one of claims 1 to 9, characterized in that: The input unit includes an incident optical fiber; The input end of the incident optical fiber is used to receive the input optical signal; The output end of the incident optical fiber is connected to the collimator.

11. The spectrometer according to any one of claims 1 to 9, characterized in that: The input unit comprises a coupling unit; The coupling unit is used to receive the input light signal of the spectrometer and couple the input light signal to the collimating mirror.

12. The spectrometer according to any one of claims 1 to 11, characterized in that The collimating lens includes a microlens or a lens.

13. A spectrum detection system, characterized in that: A spectrometer comprising a light source and any one of claims 1 to 12; The light source is used to illuminate the substance to be measured to obtain an input light signal of the spectrometer; The spectrometer is used to receive and detect the input optical signal.

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