Miniaturized spectral sensing system and method based on MEMS grating scanning

Abstract

The application relates to the technical field of spectral analysis, and discloses a miniaturized spectral sensing system and method based on MEMS grating scanning, which comprises the following: an optical input module for receiving to-be-detected light; a collimating optical element for collimating the to-be-detected light to form a parallel light beam; a MEMS grating scanning micromirror for dispersing and spectrally analyzing the parallel light beam; a focusing optical element for focusing the incident light to form to-be-detected light signals of different wavelengths; a single infrared detector for converting the to-be-detected light signals into electrical signals; and a signal processing module for extracting the intensity of the to-be-detected light signals based on the electrical signals, identifying the wavelengths of the to-be-detected light signals corresponding to the electrical signals, thereby binding the wavelengths and the intensity of the to-be-detected light signals, and drawing a spectral graph. The application utilizes a micro-electro-mechanical system integrated micro-nano optical surface, combines a high-performance single infrared detector, realizes high-precision and miniaturized measurement of infrared spectrum, and improves the error resistance of grating scanning.

Description

Technical Field

[0001] This application relates to the technical field of spectral analysis, specifically to a miniaturized spectral sensing system and method based on MEMS grating scanning. Background Technology

[0002] Traditional infrared spectrometers typically employ gratings or prisms for beam splitting, coupled with linear or area array infrared focal plane array detectors. This results in problems such as large size, high cost, and complex manufacturing processes. Fourier transform infrared spectrometers use Michelson interferometers and unit detectors, avoiding array detectors, but the moving mirror scanning mechanism is complex and precise, making miniaturization difficult, and they are sensitive to environmental vibrations. Spectrometers based on digital micromirror devices, such as the DLP solution from Texas Instruments, have no macroscopic moving parts and offer good programmability, but they suffer from low light energy utilization, a significant decrease in infrared reflectivity, and diffraction crosstalk issues, which limit the signal-to-noise ratio in weak infrared signal detection.

[0003] In existing technologies, unit detectors typically acquire the intensity of incident light signals at different times. Their output signals not only contain useful spectral information but also include dark current, low-frequency drift, environmental noise, and interference introduced by the electronic system. Due to limitations in overall system size, it is difficult to incorporate complex optical modulation structures or multi-stage optical path isolation. These interferences often directly affect the detected signal, adversely impacting the identification of weak absorption features. This is especially true in the mid-infrared band, where the detector itself is highly sensitive to temperature and background radiation, making the low-frequency noise problem even more pronounced.

[0004] For example, Chinese Patent CN114838823B discloses a method and system for reconstructing spectral information based on a scanning grating micromirror spectrometer. This method acquires the data to be reconstructed from the scanning grating micromirror spectrometer, generates a position sequence based on the scanning speed feedback signal, a preset length, and a preset time interval, generates the reconstructed wavelength corresponding to each position sequence value based on the characteristic peak wavelength value of the light source and the position sequence value, and generates the reconstructed spectral information of the scanning grating micromirror spectrometer based on the reconstructed wavelength and light intensity signal corresponding to each position sequence value. Through the spectral information reconstruction method, in the design of a miniature near-infrared spectrometer system based on a scanning grating micromirror, the reconstructed spectral information can be generated by combining the light intensity signal of a single-tube photodetector and the scanning speed feedback signal of the scanning grating micromirror, which can directly reflect the spectral information required by the user.

[0005] For example, Chinese patent application CN113552090A discloses a near-infrared fluorescence spectrometer based on a micro-scanning grating micromirror, including a detection chamber, a fluorescence excitation module, and a near-infrared fluorescence spectroscopy and spectrum acquisition module. This invention achieves rapid acquisition of near-infrared full-spectrum information by integrating a scanning grating micromirror. Combined with the fluorescence excitation module, it can obtain the three-dimensional full spectrum of the analyte within one minute. The fluorescence excitation module can effectively reduce the influence of coma. The plano-convex cylindrical mirror in the near-infrared fluorescence spectroscopy and spectrum acquisition module ensures the imaging quality of the near-infrared fluorescence spectrum, reduces aberrations caused by the optical system during fluorescence spectral information acquisition, and improves spectral resolution and signal-to-noise ratio. It uses a single-tube detector to realize near-infrared spectral information detection. While ensuring the speed of spectral information acquisition, it simplifies the optical system structure and reduces costs, and has the advantages of wide spectrum, high resolution, and fast detection speed.

[0006] All of the above technical solutions suffer from the problem mentioned in the background of this application: low-frequency noise is difficult to suppress.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The technical problem to be solved by this application is to overcome the defects of the prior art and provide a miniaturized spectral sensing system and method based on MEMS grating scanning. It utilizes micro-nano optical surfaces integrated by micro-electromechanical systems (MEMS) and combines them with high-performance unit infrared detectors to achieve high-precision and miniaturized infrared spectral measurement.

[0009] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0010] On the one hand, this application provides a miniaturized spectral sensing system based on MEMS grating scanning, comprising:

[0011] An optical input module is provided with an entrance slit for receiving the light to be measured; a collimating optical element is provided for collimating the light to be measured to form a parallel beam.

[0012] MEMS grating scanning micromirrors are used to disperse the parallel beam and, through scanning motion, cause light of different wavelengths to be reflected sequentially into the entrance aperture of the focusing optical element; the focusing optical element focuses the incident light to form light signals of different wavelengths to be measured.

[0013] The unit infrared detector is used to convert the light signal to be measured into an electrical signal; the signal processing module extracts the intensity of the light signal to be measured based on the electrical signal and identifies the wavelength of the light signal to be measured corresponding to the electrical signal, thereby binding the wavelength and intensity of the light signal to be measured and plotting the spectrum.

[0014] A control and drive module is used to drive the MEMS grating scanning micromirror to introduce phase identification information during the scanning motion; a signal processing module corrects the wavelength of the optical signal to be measured corresponding to the electrical signal based on the phase identification information.

[0015] MEMS grating scanning micromirrors include a reflective surface, a driving mechanism, and a support beam;

[0016] The driving mechanism also includes a second driver; the driving MEMS grating scanning micromirror introduces phase identification information during the scanning motion, specifically including: generating a second driving signal and sending it to the second driver, the second driver driving the reflective surface to jitter around the second scanning axis based on the second driving signal, so that the light entering the entrance aperture of the focusing optical element carries phase identification information; the phase identification information includes the phase and frequency of the jitter motion;

[0017] For any given moment, the wavelength of the optical signal under test corresponding to the electrical signal is corrected based on the phase identification information, specifically including:

[0018] The electrical signal output by the unit infrared detector is multiplied with the second drive signal output by the control drive module at the same time to obtain the synchronous product signal;

[0019] The synchronous product signal is low-pass filtered to obtain the complex demodulated quantity of the electrical signal;

[0020] The phase residual of the electrical signal is extracted based on the complex demodulation quantity, and the modulation phase of the electrical signal is calculated based on the phase residual.

[0021] The rotation angle at the corresponding moment is corrected based on the modulation phase of the electrical signal, and the wavelength corresponding to the corrected rotation angle is queried based on the mapping relationship, which is used as the correction result.

[0022] The reflective surface is integrated with micro-nano optical surfaces for dispersing the parallel beam and providing different reflection angles for different wavelengths of light. The micro-nano optical surfaces are formed by bonding on the reflective surface through micro-nano fabrication processes or by integral etching on the reflective surface.

[0023] As a preferred embodiment of the miniaturized spectral sensing system based on MEMS grating scanning described in this application, the driving mechanism includes a first driver for driving the reflective surface to perform scanning motion; the scanning motion is a unidirectional continuous sawtooth wave scanning or a unidirectional step scanning around the first scanning axis, specifically including: causing the angle between the reflective surface and the reference plane to change continuously or stepwise, so that the reflection direction of light of each wavelength changes continuously or stepwise, thereby realizing that light of different wavelengths is reflected sequentially into the entrance aperture of the focusing optical element;

[0024] The support beam is used to provide rotational freedom and stiffness for the rotation of the reflecting surface.

[0025] As a preferred embodiment of the miniaturized spectral sensing system based on MEMS grating scanning described in this application, wherein: the unit infrared detector is disposed in the focal region of the focusing optical element, and the diameter of the photosensitive surface is greater than or equal to μm;

[0026] The MEMS grating scanning micromirror also includes a position sensing unit for real-time detection of the rotation angle of the reflecting surface; the rotation angle is the angle between the reflecting surface and the reference plane; the position sensing unit includes a movable interdigitated electrode and a fixed interdigitated electrode; the movable interdigitated electrode is disposed on the outer side of the micro / nano optical surface, and the fixed interdigitated electrode is disposed on the substrate of the MEMS grating scanning micromirror.

[0027] As a preferred embodiment of the miniaturized spectral sensing system based on MEMS grating scanning described in this application, the signal processing module has a built-in mapping relationship between rotation angle and wavelength; the mapping relationship is used to query the wavelength of the light signal to be measured received by the infrared detector of the unit according to the rotation angle of the reflective surface.

[0028] The identification of the wavelength of the optical signal to be tested corresponding to the electrical signal specifically includes: synchronously receiving the rotation angle output by the position sensing unit and the electrical signal output by the unit's infrared detector; querying the wavelength of the optical signal to be tested corresponding to the currently received rotation angle based on the mapping relationship, and using it as the wavelength of the optical signal to be tested corresponding to the currently received electrical signal.

[0029] As a preferred embodiment of the miniaturized spectral sensing system based on MEMS grating scanning described in this application, the control driving module is further configured to generate a first driving signal and send it to a first driver; the first driving signal is used to control the first driver to drive the scanning motion of the reflective surface.

[0030] As a preferred embodiment of the miniaturized spectral sensing system based on MEMS grating scanning described in this application, the second driving signal includes a phase encoding function; the phase encoding function is used to set the phase of the second driving signal according to the rotation angle detected in real time by the position sensing unit.

[0031] As a preferred embodiment of the miniaturized spectral sensing system based on MEMS grating scanning described in this application, wherein: the phase residual of the electrical signal is the phase of the complex demodulated quantity; the modulation phase of the electrical signal is calculated based on the phase residual, specifically including: extracting the phase of the second driving signal at the corresponding time as a reference phase; the modulation phase of the electrical signal is the sum of the reference phase and the phase residual;

[0032] The method of correcting the rotation angle at the corresponding moment based on the modulation phase of the electrical signal specifically includes: substituting the modulation phase of the electrical signal into the inverse function of the phase encoding function, and solving for the rotation angle at the corresponding moment as the correction result.

[0033] Secondly, this application provides a miniaturized spectral sensing method based on MEMS grating scanning, comprising the following steps:

[0034] Receive the light to be measured and collimate it to form a parallel beam;

[0035] The parallel beam is dispersed and split; the reflection direction of light of different wavelengths is changed by scanning motion, and phase identification information is introduced in the scanning motion;

[0036] Light of each wavelength is focused sequentially to form light signals of different wavelengths to be measured;

[0037] The optical signal to be tested is converted into an electrical signal;

[0038] The intensity of the optical signal to be measured is extracted based on the electrical signal, and the wavelength of the optical signal to be measured corresponding to the electrical signal is identified.

[0039] Based on the phase identification information, the wavelength of the optical signal under test corresponding to the corrected electrical signal is determined, thereby binding the wavelength and intensity of the optical signal under test and plotting the spectrum.

[0040] Compared with the prior art, the beneficial effects achieved by this application are as follows:

[0041] This application addresses the common problems of scan motion error accumulation, zero-point drift, and dynamic nonlinearity in miniature scanning spectral sensing systems. It enhances the ability to perceive and constrain changes in scanning state at the system level, significantly improving the consistency of spectral data acquired at different working times and scanning cycles on the wavelength axis, and effectively reducing the probability of overall spectral shift and local distortion.

[0042] Compared to traditional solutions that rely on a single angle or displacement measurement signal, this application effectively mitigates measurement errors caused by manufacturing deviations in the scanning structure, non-ideal driving conditions, or environmental changes, thereby improving the system's robustness under complex operating conditions. This application does not rely on adding large optical components or complex external modules, avoiding a significant increase in size, power consumption, and cost, making it suitable for applications with high requirements for size, power consumption, and integration. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0044] Figure 1 A schematic diagram of a miniaturized spectral sensing system based on MEMS grating scanning provided in this application;

[0045] Figure 2 This is a top view of the structure of the MEMS grating scanning micromirror provided in this application;

[0046] Figure 3 This is a cross-sectional view of the MEMS grating scanning micromirror provided in this application;

[0047] Figure 4 A schematic diagram of the spectral scanning principle provided in this application.

[0048] Explanation of reference numerals in the attached figures: 110, Optical input module; 120, Collimating optical element; 130, MEMS grating scanning micromirror; 140, Focusing optical element; 150, Unit infrared detector; 160, Control and drive module; 170, Signal processing module; 131, Reflecting surface; 132, Micro / nano optical surface; 133, Drive mechanism; 133a, First driver; 133b, Second driver; 134, Support beam; 135, Position sensing unit; 135a, Movable interdigitated electrode; 135b, Fixed interdigitated electrode. Detailed Implementation

[0049] The technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of this application, rather than limitations thereof. In the absence of conflict, the embodiments and technical features in the embodiments can be combined with each other.

[0050] Example 1

[0051] This solution can be implemented as a spectrometer of various specifications and applications. This embodiment, focusing on the application and functional characteristics of a mid-wave infrared gas analysis spectrometer, introduces a miniaturized spectral sensing system based on MEMS grating scanning; refer to... Figure 1 The system includes an optical input module 110, a collimating optical element 120, a MEMS grating scanning micromirror 130, a focusing optical element 140, a unit infrared detector 150, a control and drive module 160, and a signal processing module 170. The functions and related parameter settings of each part are as follows.

[0052] The optical input module 110 is provided with an entrance slit for receiving the light to be measured; the collimating optical element 120 is used to collimate the light to be measured to form a parallel beam.

[0053] Optionally, the entrance slit of the optical input module 110 has a width of 100 μm and a height of 2 mm, and is used to receive infrared light from the gas sample to be tested. The collimating optical element 120 uses an off-axis parabolic mirror with a focal length of 50 mm and an off-axis angle of 30°. The material is gold-plated aluminum alloy to ensure high reflectivity, thereby collimating the diverging light emitted from the entrance slit into a parallel beam.

[0054] MEMS grating scanning micromirror 130 is used to disperse the parallel beam and, through scanning motion, cause light of different wavelengths to be reflected sequentially into the entrance aperture of focusing optical element 140; focusing optical element 140 focuses the incident light to form light signals of different wavelengths to be measured.

[0055] like Figure 2 As shown, the MEMS grating scanning micromirror 130 includes a reflective surface 131, a driving mechanism 133, and a support beam 134;

[0056] A micro-nano optical surface 132 is integrated on the reflective surface 131 to disperse the parallel beam and provide different reflection angles for different wavelengths of light; the micro-nano optical surface 132 is formed by bonding on the reflective surface 131 through micro-nano fabrication process, or by integral etching on the reflective surface 131.

[0057] Optionally, the MEMS grating scanning micromirror 130 uses a single-crystal silicon substrate with a size of 5mm x 5mm, and the reflective surface 131 has a size of 3mm x 3mm. For example... Figure 3 As shown, the grating constant of the micro-nano optical surface 132 is 3.33 μm; the diffraction efficiency is optimized for mid-wave infrared light, and the blaze angle is 31.65°.

[0058] The driving mechanism 133 includes a first driver 133a for driving the reflective surface 131 to perform scanning motion; the scanning motion is a unidirectional continuous sawtooth wave scanning or a unidirectional step scanning around the first scanning axis, specifically including: making the angle between the reflective surface 131 and the reference plane change continuously or stepwise, so that the reflection direction of light of each wavelength changes continuously or stepwise, thereby realizing that light of different wavelengths is reflected sequentially into the entrance aperture of the focusing optical element 140;

[0059] Optionally, the drive mechanism 133 can be selected from electrostatic comb drive, electromagnetic drive, and piezoelectric drive; the first driver 133a is a set of differential comb drivers, using quasi-static drive, with a maximum mechanical scanning angle of ±15°; the reference plane can be a horizontal plane or other plane that can provide a reference. The first scanning axis is in Figure 2 The plane shown is vertical and perpendicular to... Figure 3 and Figure 4 The plane shown.

[0060] The support beam 134 is used to provide rotational freedom and stiffness for the rotation of the reflector 131.

[0061] The focusing optical element 140 is an off-axis parabolic mirror with a focal length of 50mm and an off-axis angle of 30°. It is made of gold-plated aluminum alloy and is used to focus and reflect light of any wavelength entering its entrance aperture to the unit infrared detector 150.

[0062] The unit infrared detector 150 is used to convert the light signal to be measured into an electrical signal; the signal processing module 170 extracts the intensity of the light signal to be measured based on the electrical signal and identifies the wavelength of the light signal to be measured corresponding to the electrical signal, thereby binding the wavelength and intensity of the light signal to be measured and plotting a spectrum.

[0063] The unit infrared detector 150 is disposed in the focal region of the focusing optical element 140, and the diameter of the photosensitive surface is greater than or equal to 200μm.

[0064] Optionally, the unit infrared detector 150 is a mercury cadmium telluride unit detector with a photosensitive surface diameter of 500 μm and an operating wavelength of 3-5 μm, cooled by liquid nitrogen or thermoelectric cooling.

[0065] Reference Figure 3The MEMS grating scanning micromirror 130 also includes a position sensing unit 135 for real-time detection of the rotation angle of the reflecting surface 131; the rotation angle is the angle between the reflecting surface 131 and the reference plane; the position sensing unit 135 includes a movable interdigitated electrode 135a and a fixed interdigitated electrode 135b; the movable interdigitated electrode 135a is disposed on the outer side of the micro / nano optical surface 132, and the fixed interdigitated electrode 135b is disposed on the substrate of the MEMS grating scanning micromirror 130. The two interdigitate in a plane to form a capacitive structure for angle detection, and the rotation angle is measured in real time by detecting changes in differential capacitance, with a resolution of less than 0.001°.

[0066] The signal processing module 170 has a built-in mapping relationship between rotation angle and wavelength; the mapping relationship is used to query the wavelength of the light signal to be measured received by the infrared detector 150 of the unit according to the rotation angle of the reflective surface 131.

[0067] The identification of the wavelength of the optical signal to be tested corresponding to the electrical signal specifically includes: synchronously receiving the rotation angle output by the position sensing unit 135 and the electrical signal output by the unit infrared detector 150; querying the wavelength of the optical signal to be tested corresponding to the currently received rotation angle based on the mapping relationship, and using it as the wavelength of the optical signal to be tested corresponding to the currently received electrical signal.

[0068] Optionally, the mapping relationship can be stored and retrieved in the form of tables, mapping functions, etc. When the rotation angle of the reflecting surface 131 changes, the reflection direction of each wavelength of light changes accordingly. At any given moment, only one wavelength of light happens to enter the incident aperture of the focusing optical element 140, thereby forming a light signal to be measured, which is recorded as an electrical signal by the unit infrared detector 150. This application determines which wavelength of light corresponds to the detected light intensity at each moment by detecting the rotation angle in real time, thereby binding the wavelength and intensity of the light signal to be measured. The signal processing module 170 sorts the intensities of different light signals to be measured based on the wavelength, and generates spectral data with equal wavelength intervals by interpolation through smoothing or super-resolution algorithms, thereby drawing a spectral graph. Optionally, the signal processing module 170 is also equipped with a correction algorithm for performing dark current correction and response nonlinearity correction on the electrical signal output by the unit infrared detector 150.

[0069] Figure 4 A schematic diagram of the scanning principle of the spectral sensing system described in this application is provided. Figure 4 The two arrows in the diagram represent the reflection directions of the two light rays with wavelengths λ1 and λ2 after dispersion at the same moment. Figure 4For simplicity, neither the collimating optical element 120 nor the focusing optical element 140 is shown. When the rotation angle changes from θ-x1 to θ-x2, the reflection directions of the two light paths with wavelengths λ1 and λ2 will change. The positions of the focusing optical element 140 and the unit infrared detector 150 in the spectral sensing system remain fixed. Therefore, at any given time, only one wavelength of light is detected. Furthermore, as the rotation angle changes over time, the wavelength of the light sent into the subsequent optical path and detected changes accordingly.

[0070] The control drive module 160 is used to drive the MEMS grating scanning micromirror 130 to introduce phase identification information during the scanning motion; the signal processing module 170 corrects the wavelength of the optical signal to be measured corresponding to the electrical signal based on the phase identification information.

[0071] The control drive module 160 is also used to generate a first drive signal and send it to the first driver 133a; the first drive signal is used to control the first driver 133a to drive the scanning motion of the reflective surface 131.

[0072] Optionally, the control drive module 160 is implemented based on FPGA or ARM; the first drive signal is a low-frequency sawtooth wave voltage with a frequency range of 0.1-200Hz.

[0073] The driving mechanism 133 also includes a second driver 133b; the driving MEMS grating scanning micromirror 130 introduces phase identification information in the scanning motion, specifically including: generating a second driving signal and sending it to the second driver 133b, the second driver 133b driving the reflecting surface 131 to jitter around the second scanning axis based on the second driving signal, so that the light entering the incident aperture of the focusing optical element 140 carries phase identification information; the phase identification information includes the phase and frequency of the jitter motion.

[0074] Optionally, the second driver 133b is a set of differential comb drivers, employing resonant drive, with a maximum mechanical scanning angle of ±2°; the second scanning axis is in Figure 2 The plane shown represents the horizontal direction. The second driving signal is a high-frequency sinusoidal voltage with an adjustable frequency range of 2-50kHz. Under the control of the second driving signal, the light spot focused on the unit infrared detector 150 will exhibit small-range periodic high-frequency jitter, achieving high-frequency jitter modulation of the optical signal under test. Combined with subsequent wavelength correction, the jitter design around the second scanning axis can suppress low-frequency noise caused by DC drift, dark current bias, and environmental disturbances, thereby improving the signal-to-noise ratio of the electrical signal without introducing complex optical paths or causing light flux loss.

[0075] The second drive signal includes a phase encoding function; the phase encoding function is used to set the phase of the second drive signal according to the rotation angle detected in real time by the position sensing unit 135.

[0076] For example, the second driving signal can be expressed as the following function:

[0077] ;

[0078] Where t represents any time point; This represents the amplitude of the second driving signal at time t; Let be the expression for the phase encoding function, representing the phase of the second driving signal at time t; This represents the rotation angle detected by the position sensing unit 135 at time t; The carrier frequency is fixed and is set to the resonant frequency of the second scanning axis. The phase encoding function can be set to a linear function, that is, the phase of the second driving signal is the product of the rotation angle and a fixed coefficient. Those skilled in the art can set the specific value of this coefficient based on actual needs.

[0079] For any given moment, the wavelength of the optical signal under test corresponding to the electrical signal is corrected based on the phase identification information, specifically including:

[0080] The electrical signal output by the unit infrared detector 150 is multiplied with the second drive signal output by the control drive module 160 at the same time to obtain the synchronous product signal.

[0081] The synchronous product signal is low-pass filtered to obtain the complex demodulated quantity of the electrical signal;

[0082] In this scheme, the second driving signal is first expanded into a complex form and then multiplied with the electrical signal; the resulting synchronous product signal is also in complex form. The second driving signal is the same source signal as the jitter of the optical signal under test. After multiplying with the electrical signal, frequency mixing occurs. The components in the electrical signal that are in phase and frequency with the second driving signal will generate a DC component after multiplication, which is retained after low-pass filtering. The low-frequency components generated by noise interference, dark current, clutter, or sensor drift in the electrical signal will generate a high-frequency component after multiplication, which is filtered out by the low-pass filter, thereby improving the signal-to-noise ratio.

[0083] The phase residual of the electrical signal is extracted based on the complex demodulation quantity, and the modulation phase of the electrical signal is calculated based on the phase residual.

[0084] The phase residual of the electrical signal is the phase of the complex demodulated quantity; the modulation phase of the electrical signal is calculated based on the phase residual, specifically including: extracting the phase of the second driving signal at the corresponding time as the reference phase; the modulation phase of the electrical signal is the sum of the reference phase and the phase residual.

[0085] When detecting rotation angle using a sensor, measurement errors can occur due to nonlinearity at small angles or across measurement ranges, hysteresis in sampling relative angle changes, and zero-point drift. If the sensor reading is directly used as the rotation angle at the current moment based on a mapping relationship, the wavelength of the measured optical signal will be incorrect, leading to spectral shift. This application uses a second driving signal as a reference to construct a complex demodulated quantity. The phase of the complex demodulated quantity is used as the phase residual to quantify the phase deviation between the true rotation angle and the measured rotation angle, thereby correcting the wavelength of the measured optical signal and solving the systemic problem of wavelength deviation caused by rotation angle error.

[0086] The rotation angle at the corresponding moment is corrected based on the modulation phase of the electrical signal, and the wavelength corresponding to the corrected rotation angle is queried based on the mapping relationship, which is used as the correction result.

[0087] The method of correcting the rotation angle at the corresponding moment based on the modulation phase of the electrical signal specifically includes: substituting the modulation phase of the electrical signal into the inverse function of the phase encoding function, and solving for the rotation angle at the corresponding moment as the correction result.

[0088] Example 2

[0089] This embodiment is the second embodiment of this application; based on the same inventive concept as Embodiment 1, this embodiment introduces a miniaturized spectral sensing method based on MEMS grating scanning, including the following steps:

[0090] The light to be tested is received and collimated to form a parallel beam, thereby providing stable and consistent incident light conditions for subsequent dispersive spectroscopy and scanning reflection.

[0091] The parallel beam is dispersed and split; the reflection direction of light of different wavelengths is changed by scanning motion, and phase identification information is introduced in the scanning motion; this is used to realize the temporal separation of light of different wavelengths during the scanning process and to provide an identifiable phase reference for the scanning state.

[0092] Light of each wavelength is focused sequentially to form light signals of different wavelengths to be measured; this is used to convert the single wavelength light selected sequentially during the scanning process into detectable light signals.

[0093] The optical signal to be tested is converted into an electrical signal, realizing the energy and information conversion from optical signal to electrical signal.

[0094] The intensity of the optical signal under test is extracted based on the electrical signal, and the wavelength of the optical signal under test corresponding to the electrical signal is identified; this is used to obtain the light intensity information corresponding to each wavelength and establish the initial wavelength correspondence.

[0095] The wavelength of the optical signal under test corresponding to the phase identification information is corrected to correct the wavelength identification deviation, so as to achieve accurate correspondence between wavelength and intensity, thereby binding the wavelength and intensity of the optical signal under test and drawing a spectrum.

[0096] The specific functions of each of the above steps are described in the relevant content of the miniaturized spectral sensing system based on MEMS grating scanning in Example 1, and will not be repeated here.

[0097] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code, including but not limited to disk storage, CD-ROM, optical storage, etc.

[0098] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of protection of this application, and these forms are all within the protection scope of this application.

Claims

1. A miniaturized spectral sensing system based on MEMS grating scanning, characterized in that: include: The optical input module (110) is provided with an entrance slit for receiving the light to be measured; A collimating optical element (120) is used to collimate the light to be measured to form a parallel beam. MEMS grating scanning micromirror (130) is used to disperse the parallel beam and make light of different wavelengths reflect into the entrance aperture of the focusing optical element (140) in sequence through scanning motion; the focusing optical element (140) focuses the incident light to form light signals of different wavelengths to be measured. A single infrared detector (150) is used to convert the optical signal to be measured into an electrical signal; The signal processing module (170) extracts the intensity of the optical signal to be measured based on the electrical signal and identifies the wavelength of the optical signal to be measured corresponding to the electrical signal, thereby binding the wavelength and intensity of the optical signal to be measured and plotting the spectrum. A control drive module (160) is used to drive the MEMS grating scanning micromirror (130) to introduce phase identification information during the scanning motion; a signal processing module (170) corrects the wavelength of the optical signal to be measured corresponding to the electrical signal based on the phase identification information; MEMS grating scanning micromirror (130) includes a reflective surface (131), a driving mechanism (133), and a support beam (134). The driving mechanism (133) includes a second driver (133b); the driving MEMS grating scanning micromirror (130) introduces phase identification information in the scanning motion, specifically including: generating a second driving signal and sending it to the second driver (133b), the second driver (133b) driving the reflecting surface (131) to jitter around the second scanning axis based on the second driving signal, so that the light entering the incident aperture of the focusing optical element (140) carries phase identification information; the phase identification information includes the phase and frequency of the jitter motion; For any given moment, the wavelength of the optical signal under test corresponding to the electrical signal is corrected based on the phase identification information, specifically including: The electrical signal output by the unit infrared detector (150) is multiplied with the second drive signal output by the control drive module (160) at the same time to obtain the synchronous product signal; The synchronous product signal is low-pass filtered to obtain the complex demodulated quantity of the electrical signal; The phase residual of the electrical signal is extracted based on the complex demodulation quantity, and the modulation phase of the electrical signal is calculated based on the phase residual. The rotation angle at the corresponding moment is corrected based on the modulation phase of the electrical signal, and the wavelength corresponding to the corrected rotation angle is queried based on the mapping relationship, which is used as the correction result.

2. The miniaturized spectral sensing system based on MEMS grating scanning as described in claim 1, characterized in that: A micro-nano optical surface (132) is integrated on the reflective surface (131) for dispersing the parallel beam and providing different reflection angles for different wavelengths of light; the micro-nano optical surface (132) is formed by bonding on the reflective surface (131) through micro-nano processing technology, or by integral etching on the reflective surface (131).

3. The miniaturized spectral sensing system based on MEMS grating scanning as described in claim 2, characterized in that: The driving mechanism (133) includes a first driver (133a) for driving the reflective surface (131) to perform scanning motion; the scanning motion is a unidirectional continuous sawtooth wave scan or a unidirectional step scan around the first scanning axis, specifically including: making the angle between the reflective surface (131) and the reference plane change continuously or stepwise, so that the reflection direction of light of each wavelength changes continuously or stepwise, thereby realizing that light of different wavelengths is reflected sequentially into the entrance aperture of the focusing optical element (140); The support beam (134) is used to provide rotational freedom and stiffness for the rotation of the reflecting surface (131).

4. The miniaturized spectral sensing system based on MEMS grating scanning as described in claim 3, characterized in that: The unit infrared detector (150) is located in the focal region of the focusing optical element (140), and the diameter of the photosensitive surface is greater than or equal to 200 μm; The MEMS grating scanning micromirror (130) also includes a position sensing unit (135) for real-time detection of the rotation angle of the reflecting surface (131); the rotation angle is the angle between the reflecting surface (131) and the reference plane; the position sensing unit (135) includes a movable interdigitated electrode (135a) and a fixed interdigitated electrode (135b); the movable interdigitated electrode (135a) is disposed on the outside of the micro-nano optical surface (132), and the fixed interdigitated electrode (135b) is disposed on the substrate of the MEMS grating scanning micromirror (130).

5. A miniaturized spectral sensing system based on MEMS grating scanning as described in claim 4, characterized in that: The signal processing module (170) has a built-in mapping relationship between rotation angle and wavelength; the mapping relationship is used to query the wavelength of the light signal to be measured received by the infrared detector (150) of the unit according to the rotation angle of the reflective surface (131); The wavelength of the optical signal to be measured corresponding to the identification electrical signal specifically includes: synchronously receiving the rotation angle output by the position sensing unit (135) and the electrical signal output by the unit infrared detector (150); Based on the mapping relationship, the wavelength of the optical signal to be measured corresponding to the currently received rotation angle is queried and used as the wavelength of the optical signal to be measured corresponding to the currently received electrical signal.

6. A miniaturized spectral sensing system based on MEMS grating scanning as described in claim 5, characterized in that: The control drive module (160) is also used to generate a first drive signal and send it to the first driver (133a); the first drive signal is used to control the first driver (133a) to drive the scanning motion of the reflective surface (131).

7. A miniaturized spectral sensing system based on MEMS grating scanning as described in claim 6, characterized in that: The second drive signal contains a phase encoding function; the phase encoding function is used to set the phase of the second drive signal according to the rotation angle detected in real time by the position sensing unit (135).

8. A miniaturized spectral sensing system based on MEMS grating scanning as described in claim 7, characterized in that: The phase residual of the electrical signal is the phase of the complex demodulated quantity; The modulation phase of the electrical signal is calculated based on the phase residual, specifically including: extracting the phase of the second driving signal at the corresponding time as a reference phase; the modulation phase of the electrical signal is the sum of the reference phase and the phase residual; The method of correcting the rotation angle at the corresponding moment based on the modulation phase of the electrical signal specifically includes: substituting the modulation phase of the electrical signal into the inverse function of the phase encoding function, and solving for the rotation angle at the corresponding moment as the correction result.

9. A miniaturized spectral sensing method based on MEMS grating scanning, implemented based on the miniaturized spectral sensing system based on MEMS grating scanning as described in any one of claims 1-8, characterized in that: Includes the following steps: Receive the light to be measured and collimate it to form a parallel beam; The parallel beam is dispersed and split; the reflection direction of light of different wavelengths is changed by scanning motion, and phase identification information is introduced in the scanning motion; Light of each wavelength is focused sequentially to form light signals of different wavelengths to be measured; The optical signal to be tested is converted into an electrical signal; The intensity of the optical signal to be measured is extracted based on the electrical signal, and the wavelength of the optical signal to be measured corresponding to the electrical signal is identified. Based on the phase identification information, the wavelength of the optical signal under test corresponding to the corrected electrical signal is determined, thereby binding the wavelength and intensity of the optical signal under test and plotting the spectrum.

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