An optical microseismometer device based on MEMS three-dimensional interferometer

Abstract

The present invention discloses an optical microseismometer device based on a MEMS three-dimensional interferometer, including a packaging shell, a MEMS interferometer module, a laser module, an optical power stabilization module, a photoelectric detection module, and a temperature control module. Physical vibration is converted into a phase change of a diffraction spot by the MEMS interferometer module, further converted into a voltage signal by the photoelectric detection module, and the acceleration response of the physical vibration is solved by a subsequent demodulation circuit; while providing a detection light source, the laser module separates a beam of light through a prism into the optical power stabilization module to suppress the drift of the laser power caused by environmental changes such as temperature, and cooperates with the temperature control module to control the stability of the internal temperature of the device, so that the low-frequency performance of the device is guaranteed and the low-frequency seismic measurement capability is greatly improved. All functional modules are fixed in the metal packaging shell to form a high-precision portable optical microseismometer device.

Description

Technical Field

[0001] The invention relates to the field of photoelectric detection technology and micro-inertial instruments and systems, and in particular to an optical microseismometer device based on a MEMS three-dimensional interferometer. Background Art

[0002] Traditional inertial instruments used for measuring ground motion usually consist of a large metal mass suspended by an elastic beam with extremely low stiffness, so as to reduce the thermal noise of the mechanical system, so that the mass can be sensitive to the ultra-weak natural vibration of the earth and convert it into mass displacement. Such instruments usually convert this displacement into a capacitance change through a capacitor plate, and then convert it into a voltage signal through a C / V circuit. With the development of global aerospace technology, the exploration of extraterrestrial planets such as the moon and Mars, and the need to explore gravitational waves in outer space, seismometers are no longer limited to use on the surface of the earth. They have become important instruments for balance control of aerospace equipment and survey of extraterrestrial landforms. Therefore, further requirements are put forward for their size, portability, and measurement accuracy. Their miniaturization technology is one of the important directions for the development of my country's national defense equipment.

[0003] Optical MEMS is a new type of optical sensor miniaturization technology developed on the basis of traditional MEMS. Various micro-nano sensitive cavities made based on MEMS, such as FP cavity, photonic crystal cavity, grating interferometer cavity, etc., have many advantages over traditional capacitive plate detection, such as no parasitic effects, ultra-high sensitivity, and no external electromagnetic interference. It has become the most important solution for micro-inertial instruments to break through performance bottlenecks. The miniaturization of sensitive structures of large seismic inertial instruments through MEMS technology and combining it with optical micro-nano cavities to achieve high-performance, small-volume microseismometers are important applications of MEMS.

[0004] At present, miniaturized seismometers made of grating interferometer cavities have been developed abroad, but their sensitive structures still use the traditional macroscopic metal structures. Therefore, there is still a lot of room for improvement in their degree of integration and mass manufacturability. China started late in this regard and no mature products have appeared yet. Summary of the invention

[0005] In order to solve the miniaturization problem of the current ground vibration survey inertial instruments, the present invention discloses an optical microseismometer device based on a MEMS three-dimensional interferometer, including a packaging shell, a MEMS interferometer module, a laser module, an optical power stabilization module, a photoelectric detection module and a temperature control module;

[0006] The packaging shell is a rectangular metal tube shell, including a coil current input / output port, a laser module power / signal port, a temperature control module power / signal port, and a photoelectric detection / optical power control module power / signal port;

[0007] The MEMS interferometer module includes a MEMS sensitive structure, a feedback coil, a coil winding bracket, coil current input and output terminals, and a module bracket. The MEMS sensitive structure is placed on the module bracket and is locked and fixed by a first screw group and a nut group, and the module bracket is fixed to the packaging shell by a second screw; wherein the MEMS sensitive structure includes an upper MEMS chip, a lower MEMS chip, a gasket, and a micro-nano grating; wherein the upper and lower MEMS chips have the same cantilever beam structure, but the thickness of the mass block is different, the thickness of the upper MEMS chip is twice the thickness of the lower MEMS chip, the upper MEMS chip is bonded to the lower MEMS chip, and the directions are arranged in opposite directions to form a three-dimensional cantilever beam structure;

[0008] The laser module includes a semiconductor laser, a collimating lens, a collimating beam, a beam splitter, a prism, a prism bracket, a driving circuit, a wedge-shaped base, a first power / signal terminal, a first power / signal interface, and the driving circuit is fixed to the wedge-shaped base through a third screw group;

[0009] The optical power stabilization module includes a photodetector, a power control circuit, a first rectangular base, a reference beam, a second power / signal terminal, a second power / signal interface, and the power control circuit is fixed to the first rectangular base through a fourth screw group;

[0010] The photoelectric detection module includes three photoelectric detectors, an interface circuit, a second rectangular base, a third power supply / signal terminal, three diffraction spots, a third power supply / signal interface, and the interface circuit is fixed to the second rectangular base through a fifth screw group;

[0011] The temperature control module includes a thermistor, a heating / cooling plate, a temperature control circuit, a third rectangular base, a fourth power / signal terminal, a fourth power / signal interface, and the temperature control circuit is fixed to the third rectangular base through a sixth screw group.

[0012] The present invention is further preferred that the upper MEMS chip in the MEMS interferometer module is composed of an upper anchor point, a first inner cantilever beam group, an upper isolation frame, a first outer cantilever beam group, an upper mass block, a permanent magnetic film, and an upper mounting aperture group; the upper mass block is square and located in the center of the structure, the permanent magnetic film is also square, has a width smaller than the upper mass block, and is located in the center of the upper mass block; the upper mass block is suspended on the anchor point by the first inner and outer cantilever beam groups, and the first inner and outer cantilever beam groups are separated by an isolation frame in the middle to avoid excessive stress concentration on the beam connection section; the first inner cantilever beam group includes first to fourth inner cantilever beams; the first outer cantilever The beam group includes the first to fourth outer cantilever beams, wherein the first inner and outer cantilever beam groups are both U-shaped structures; the length of the first to fourth inner cantilever beams is longer than the width of the upper mass block, and the length of the first to fourth outer cantilever beams is longer than the width of the upper isolation frame, so as to increase space utilization and maximize the elasticity of the beam; the thickness of the first inner and outer cantilever beam groups is less than the thickness of the upper mass block, and the thickness of the upper isolation frame and the upper anchor point is the same as that of the upper mass block, so as to obtain a sufficiently small support stiffness; the upper mounting aperture group includes the first to fourth circular apertures; wherein the first to fourth circular apertures are distributed at the four corners of the upper anchor point, and are used to fix the MEMS sensitive structure on the module bracket;

[0013] The structure of the lower MEMS chip is consistent with that of the upper MEMS chip, but the coating material and thickness are different. The lower MEMS chip consists of a lower anchor point, a lower inner cantilever beam, a lower isolation frame, a second outer cantilever beam group, a lower mass block, a reflective film, a thermosensitive film, a resistive film, and a lower mounting aperture group; the lower mass block is square and located in the center of the structure, and the reflective film is also square, with a width smaller than that of the lower mass block, and is located in the center of the lower mass block; the lower mass block is suspended on the lower anchor point by the second inner and outer cantilever beam groups, and the second inner and outer cantilever beam groups are separated by the lower isolation frame;

[0014] The second inner cantilever beam group includes the fifth to eighth inner cantilever beams; the second outer cantilever beam group includes the fifth to eighth inner cantilever beams; the length of the fifth to eighth inner cantilever beams is longer than the width of the lower mass block, and the length of the fifth to eighth outer cantilever beams is longer than the width of the lower isolation frame; the second inner and outer cantilever beam groups are smaller than the thickness of the lower mass block,

[0015] The thickness of the lower isolation frame and the lower anchor point is the same as that of the lower mass block; the thermal film is composed of a rectangular thermal module and a first input and output module, and is located in the middle position above the lower anchor point; the resistance film is composed of a "snake-shaped" resistance module and a second input and output module, and is located in the middle position below the lower anchor point, and both are used to more precisely monitor and control the temperature of the MEMS sensitive structure when the temperature in the package shell is basically stable; the lower mounting aperture group includes the fifth to eighth circular apertures; the fifth to eighth circular apertures are distributed at the four corners of the lower anchor point, and are used to fix the MEMS sensitive structure on the module bracket;

[0016] The gasket is an annular structure, which is consistent with the structure of the upper and lower anchor points, but the thickness is different. The thickness of the gasket is one fifth of the thickness of the lower MEMS chip; the four corners of the gasket are provided with ninth to twelfth circular apertures for fixing the MEMS sensitive structure on the module bracket;

[0017] The micro-nano grating consists of a substrate and a grating rack. The substrate is a transparent material, and the substrate area is consistent with the total area of ​​the upper and lower MEMS chips; the width of the grating rack is 1.5 to 2 microns, and the rack width is consistent with the gap width, that is, the duty cycle is 50%, the thickness is 50 to 100 nanometers, and the material is a highly reflective metal material, such as gold, silver, chromium, etc.

[0018] The four corners of the substrate are provided with thirteenth to sixteenth circular apertures for fixing the MEMS sensitive structure on the module bracket.

[0019] The present invention is further preferred that the module bracket is a "concave" structure, wherein the lengths of the left and right fixing pages are smaller than the middle supporting page portion, the upper and lower ends of the left fixing page are provided with first and second screw apertures; the upper and lower ends of the right fixing page are provided with third and fourth screw apertures for fixing it to the packaging shell; the middle supporting page is a hollow structure, the opening area is larger than the total area of ​​the cantilever beam portions of the upper and lower MEMS chips, the nut group includes first to fourth nuts; the first screw group includes first to fourth screws;

[0020] The MEMS sensitive structure is fixed to the outside of the four corners of the opening by the first to fourth screws and the first to fourth nuts, so that the first outer and inner cantilever beam groups and the upper mass block can move freely up and down in the opening; the main body of the coil winding bracket is a hollow square ring structure, the winding shape of the coil is also square, the width of the coil is smaller than the width of the permanent magnetic film, which is three-quarters of the width, and the center of the coil coincides with the center of the permanent magnetic film to ensure that the direction of the electromagnetic feedback force is perpendicular to the upper mass block; the coil winding bracket is fixed to the support page of the module bracket by the long strip support arms on both sides thereof, and the screws and nuts on both sides are located to the left and right of the center of the left and right support arms respectively.

[0021] The present invention is further preferred, wherein the area of ​​the driving circuit in the laser module is smaller than the area of ​​the wedge-shaped base, the centers of the two coincide, and the third screw group includes first to fourth driving circuit screws; the driving circuit is fixed to the wedge-shaped base by first to fourth driving circuit fixing screws on its four corners; the semiconductor laser is located to the right of the middle of the driving circuit in the horizontal direction and in the middle of the driving circuit in the vertical direction; the beam splitter prism is a cube, which is supported directly above the semiconductor laser by a circular hollow bracket to ensure that the light beam can propagate along the original path; the bottom area of ​​the collimating lens is smaller than the upper surface area of ​​the semiconductor laser and is located in its center; the first power / signal interface is located to the right of the semiconductor laser and is used to connect the first power / signal terminal.

[0022] The present invention is further preferred that the area of ​​the power control circuit in the optical power stabilization module is slightly smaller than the area of ​​the first rectangular base, the centers of the two coincide, the fourth screw group includes first to fourth power control circuit fixing screws; the power control circuit is fixed to the first rectangular base through the first to fourth power control circuit fixing screws on its four corners; the photodetector is located in the middle of the control circuit both horizontally and vertically; the light-sensitive chip of the photodetector is square and located in the center of the circular packaging tube shell; the second power / signal interface is located directly below the photodetector and is used for the second connection power / signal terminal.

[0023] The present invention is further preferred, the area of ​​the interface circuit in the photoelectric detection module is slightly smaller than the area of ​​the second rectangular base, the centers of the two coincide, the fifth screw group includes first to fourth interface circuit fixing screws; the interface circuit is fixed on the second rectangular base by the first to fourth interface circuit fixing screws; the first to third photodetectors are located in the middle of the interface circuit in the horizontal direction, the second photodetector is located in the middle of the interface circuit in the vertical direction, the first and third photodetectors are respectively located above and below the second photodetector; the first to third photodetector light sensitive chips are all square, and are located in the center of the first to third circular packaging tube shells; the third power / signal interface is located to the right of the second photodetector, and is used to connect the third power / signal terminal.

[0024] The present invention is further preferred that the area of ​​the temperature control circuit in the temperature control module is smaller than the area of ​​the third rectangular base, and the centers of the two coincide; the sixth screw group includes first to fourth temperature control circuit fixing screws, and the temperature control circuit is fixed to the third rectangular base through the first to fourth temperature control circuit fixing screws; the thermistor is located on the left side of the third rectangular base, and the heating / cooling plate is located on the right side of the third rectangular base, and both are located in the middle of the third rectangular base in the vertical direction; the fourth power / signal interface is located on the left side of the middle of the temperature control circuit, flush with the thermistor and the heating / cooling plate, and is used to connect the fourth power / signal terminal.

[0025] The implementation method of the optical microseismometer device based on MEMS three-dimensional interferometer includes the following process:

[0026] The laser module generates a collimated laser beam, which is split by a beam splitter into two sub-beams with the same intensity and perpendicular directions. One sub-beam is directed toward the MEMS interferometer module from the original path, and the other sub-beam is directed toward the optical power stabilization module from the vertical direction to the right.

[0027] The sub-beam directed to the MEMS interferometer module is divided into several diffraction spots by the interference cavity formed by the micro-nano grating and the reflective film. The phases of these diffraction spots are modulated by the length of the MEMS interference cavity. The ultra-sensitive detector composed of the upper and lower MEMS chips converts the environmental vibration into the displacement of the reflective film, which in turn brings about the change of the interference cavity length. Therefore, the phase of the diffraction spot can reflect the vibration of the physical environment in which the device is located, thereby achieving the purpose of detecting weak earthquakes; because the laser emits the laser beam at an angle, the first three order diffraction spots are reflected at an angle along the symmetrical direction, which can be simultaneously received by the photoelectric detection module located on the bottom right, which converts the optical signal into voltage signal, so that the magnitude of the detected vibration can be solved by the subsequent demodulation circuit; the 0-level spot is in opposite phase to the ±1-level spot, and the purpose of differential detection can be achieved by subtracting the 0-level spot interface voltage from the -1 / +1-level interface voltage, which is beneficial to suppress the common-mode noise of the interface module; when the feedback coil is energized, a feedback electromagnetic force is generated between it and the permanent magnetic film, stabilizing the detection mass block in a balanced position to increase the detection bandwidth and dynamic range of the device; the lower MEMS chip contains a thermal film and a resistor film, which are used to precisely measure and control the temperature of the MEMS sensitive structure to minimize the interference caused by the drift of the interference cavity length;

[0028] The intensity of the sub-beam directed to the optical power stabilization module does not change with environmental vibrations. It is converted into a voltage signal by the photodetector in the module and controlled at a constant ideal power by the power control circuit, thereby suppressing the power drift of the laser caused by changes in environmental factors such as temperature, thereby achieving the purpose of enhancing the low-frequency noise performance of the device;

[0029] The thermistor in the temperature control module can detect the ambient temperature inside the metal packaging shell. Since temperature drift will have a large noise impact on the MEMS sensitive module, laser module, and various analog circuits, the temperature control circuit is used to control the heating / cooling plate to achieve the purpose of stabilizing the internal temperature of the device, thereby enhancing the long-term stability of the device and the overall noise performance.

[0030] Beneficial effects of the present invention:

[0031] (1) The present invention encapsulates the laser module, MEMS interferometer, photoelectric detection module, optical power stabilization module, and temperature control module in a compact metal housing to form a portable microseismometer, the total volume of which can be controlled at the order of hundreds of cubic centimeters. Compared with large commercial instruments such as seismometers and gravimeters, the integration level is greatly improved and the cost is greatly reduced;

[0032] (2) The present invention bonds two silicon micro-sensitive chips of different thicknesses together as a detector. The bonded structure is completely symmetrical in the vertical and horizontal directions. The first two resonant frequencies of the structure can be separated to more than 100 Hz, forming a high-sensitivity, low cross-coupling MEMS detector. In addition, the structure of a 3D beam is realized by planar MEMS processing.

[0033] (3) The present invention uses photoelectric detection to detect tiny vibrations, overcoming the parasitic capacitance effect caused by capacitance detection in traditional inertial instruments. Differential detection suppresses common-mode noise in the interface circuit, thereby greatly improving the device's ability to detect ultra-small vibrations, acceleration and other physical quantities;

[0034] (4) The present invention controls the light source power by separating a reference beam through a prism, and maintains the internal temperature of the device at a stable value through a temperature control module. At the same time, a thermistor film and a resistor film are plated on the MEMS chip to further refine the temperature control of the MEMS sensitive structure, effectively solving the interference to the device caused by ambient temperature changes, greatly improving the low-frequency noise of the device, and enhancing its low-frequency measurement capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is an overall front cross-sectional view of the present invention;

[0036] Figure 2 The top view or bottom view of each substructure of the MEMS sensitive structure of the present invention, wherein (a) is a bottom view of the upper MEMS chip, (b), (c), and (d) are top views of the lower MEMS chip, the gasket, and the micro-nano grating, respectively;

[0037] Figure 3 A top view of the MEMS interferometer module of the present invention;

[0038] Figure 4 is a top view of the laser module of the present invention;

[0039] Figure 5 It is a left view of the optical power stabilization module of the present invention;

[0040] Figure 6 is a top view of the photoelectric detection module of the present invention;

[0041] Figure 7It is a top view of the temperature control module of the present invention. DETAILED DESCRIPTION

[0042] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0043] like Figure 1 As shown, this embodiment provides an optical microseismometer device based on a MEMS three-dimensional interferometer, including a packaging shell 1, a MEMS interferometer module 2, a laser module 3, an optical power stabilization module 4, a photoelectric detection module 5 and a temperature control module 6;

[0044] The package shell 1 is a rectangular metal tube shell, including a coil current input / output port 101, a laser module power / signal port 102, a temperature control module power / signal port 103, and a photoelectric detection / optical power control module power / signal port 104;

[0045] The MEMS interferometer module 2 includes a MEMS sensitive structure 201, a feedback coil 212, a coil winding bracket 211, coil current input and output terminals 206a, 206b, a module bracket 209, the MEMS sensitive structure 201 is placed on the module bracket 209 and is locked and fixed by a first screw group 207 and a nut group 208, and the module bracket 209 is fixed to the packaging shell 1 by a second screw 210; wherein the MEMS sensitive structure 201 includes an upper MEMS chip 202, a lower MEMS chip 203, a gasket 204, and a micro-nano grating 205; wherein the upper and lower MEMS chips 202, 203 have the same cantilever beam structure, but the thickness of the mass block is different, the thickness of the upper MEMS chip 202 is twice the thickness of the lower MEMS chip 203, the upper MEMS chip 202 is bonded to the lower MEMS chip 203, and the directions are arranged in opposite directions to form a three-dimensional cantilever beam structure;

[0046] The optical power stabilization module 4 includes a photodetector 401, a power control circuit 402, a first rectangular base 403, a reference beam 405, a second power / signal terminal 406, a second power / signal interface 407, and the power control circuit 402 is fixed to the first rectangular base 403 by a fourth screw group 404;

[0047] The photoelectric detection module 5 includes three photoelectric detectors 501, an interface circuit 502, a second rectangular base 503, a third power supply / signal terminal 505, three diffraction light spots 506, a third power supply / signal interface 507, and the interface circuit 502 is fixed to the second rectangular base 503 by a fifth screw group 504;

[0048] The temperature control module 6 includes a thermistor 601, a heating / cooling plate 602, a temperature control circuit 603, a third rectangular base 604, a fourth power / signal terminal 606, a fourth power / signal interface 607, and the temperature control circuit 603 is fixed to the third rectangular base 604 by a sixth screw group 605.

[0049] The MEMS interferometer module 2 is fixed to the middle left position of the top of the package shell 1 through the module bracket 209, which is easy to disassemble so that the laser beam can be irradiated to its center position. The coil current input and output terminals 206a, 206b are led out through the coil current input / output port 101 on the package shell 1, and the port 101 is located at the middle left position of the top of the package shell 1; the laser module 3 is fixed to the middle position of the left side wall of the package shell 1 through the inclined wedge-shaped base 307, while reducing the laser intensity loss, so that the diffracted light beam 506 can be tilted to irradiate into the photoelectric detection module 5, and its first power / signal terminal 309 is led out through the laser module power / signal port 102 on the package shell 1, and the port 102 is located at the middle upper position of the left side wall of the package shell 1; the optical power stabilization module 4 is fixed to the package The middle position of the right side wall of the shell 1 is convenient for receiving the reference beam 405, and its power / signal terminal 406 is led out through the power / signal port 104 of the photoelectric detection / optical power control module on the packaging shell 1, and the port 104 is located in the middle and lower position of the right side wall of the packaging shell; the photoelectric detection module 5 and the temperature control module 6 are fixed to the bottom of the packaging shell 1, wherein the photoelectric detection module 5 is located on the right side, so as to receive the reflected diffracted beam 506, and its power / signal terminal 505 is led out through the power / signal port 103 of the temperature control module 6 on the packaging shell 1, and the port 103 is located in the middle and lower position of the left side wall of the packaging shell 1, and the temperature control module 6 is located on the right side, and its fourth power / signal terminal 606 is led out through the power / signal port 104 of the photoelectric detection / optical power control module on the packaging shell 1.

[0050] The implementation method of the micro optical seismometer based on MEMS three-dimensional interferometer includes the following processes:

[0051] The laser module 3 generates a collimated laser beam 303, and the beam splitter prism 305 splits the beam into two sub-beams with the same intensity and perpendicular directions. One of the sub-beams is directed toward the MEMS interferometer module 2 from the original path, and the other sub-beam 405 is directed toward the optical power stabilization module 4 from the vertical direction to the right.

[0052] The sub-beam directed to the MEMS interferometer module 2 is divided into a number of diffraction spots by the interference cavity formed by the micro-nano grating 205 and the reflective film 2036. The phases of these diffraction spots are modulated by the length of the MEMS interference cavity. The ultra-sensitive detector composed of the upper and lower MEMS chips 202 and 203 converts the environmental vibration into the displacement of the reflective film 2036, which in turn brings about the change of the interference cavity length. Therefore, the phase of the diffraction spot can reflect the vibration of the physical environment in which the device is located, thereby achieving the purpose of detecting weak earthquakes; since the laser 301 obliquely emits the laser beam 303, the first three-order diffraction beams 506a, 506b, and 506c are obliquely reflected in the symmetrical direction, which can be simultaneously received by the photoelectric detection module 5 located on the bottom right, which converts the optical signal into The voltage signal is converted into a voltage signal, so that the magnitude of the detected vibration can be solved by the subsequent demodulation circuit; the 0-level light spot 506b is opposite in phase to the ±1-level light spots 506a and 506c, and the purpose of differential detection can be achieved by making a difference between the 0-level interface voltage and the -1 / +1-level interface voltage, which is beneficial to suppressing the common-mode noise of the interface module; when the feedback coil 212 is energized, a feedback electromagnetic force is generated between it and the permanent magnetic film 2026, stabilizing the detection mass block at a balanced position to increase the detection bandwidth and dynamic range of the device; the lower MEMS chip 203 includes a thermal film 2038 and a resistor film 2039, which are used to precisely measure and control the temperature of the MEMS sensitive structure 201 to minimize the interference caused by the drift of the interference cavity length;

[0053] The intensity of the sub-beam 405 directed to the optical power stabilization module 4 does not change with environmental vibrations. It is converted into a voltage signal by the photodetector 401 in the module, and is controlled at a constant ideal power by the power control circuit 402, thereby suppressing the power drift of the laser 301 caused by changes in environmental factors such as temperature, thereby achieving the purpose of enhancing the low-frequency noise performance of the device;

[0054] The thermistor 601 in the temperature control module 6 can detect the ambient temperature inside the metal packaging shell 1. Since temperature drift will produce a large noise impact on the MEMS sensitive module 201, the laser module 3, and the analog circuits 306, 402, 502, and 603, the heating / cooling plate 602 is controlled by the temperature control circuit 603 to achieve the purpose of stabilizing the internal temperature of the device, thereby enhancing the long-term stability of the device and the overall noise performance.

[0055] like Figure 2As shown in (a), the upper MEMS chip 202 in the MEMS interferometer module 2 is composed of an upper anchor point 2021, a first inner cantilever beam group 2023, an upper isolation frame 2024, a first outer cantilever beam group 2022, an upper mass block 2025, a permanent magnetic film 2026, and an upper mounting aperture group 2027; the upper mass block 2025 is square and located in the center of the structure, and the permanent magnetic film 2026 is also square, with a width smaller than the upper mass block 2025, and is located in the center of the upper mass block 2025; the upper mass block 2025 is square and located in the center of the structure. The block 2025 is suspended on the anchor point 2021 by the first inner and outer cantilever beam groups 2023 and 2022. The first inner and outer cantilever beam groups 2023 and 2022 are separated by an isolation frame 2024 to avoid excessive stress concentration on the beam connection section; the first inner cantilever beam group 2023 includes the first to fourth inner cantilever beams 2023a, 2023b, 2023c, and 2023d; the first outer cantilever beam group 2022 includes the first to fourth outer cantilever beams 2022a, 2022b, 2022 c, 2022d, wherein the first inner and outer cantilever beam groups are both U-shaped structures; the lengths of the first to fourth inner cantilever beams 2023a, 2023b, 2023c, 2023d are longer than the width of the upper mass block 2025, and the lengths of the first to fourth outer cantilever beams 2022a, 2022b, 2022c, 2022d are longer than the width of the upper isolation frame 2024, so as to increase space utilization and maximize the elasticity of the beams; the thickness of the first inner and outer cantilever beam groups 2023, 2022 is less than the thickness of the upper mass block 202 5, the thickness of the upper isolation frame 2024 and the upper anchor point 2021 is the same as that of the upper mass block 2025, so as to obtain a sufficiently small support stiffness; the upper mounting aperture group 2027 includes first to fourth circular apertures 2027a, 2027b, 2027c, and 2027d; wherein the first to fourth circular apertures 2027a, 2027b, 2027c, and 2027d are distributed at the four corners of the upper anchor point 2021, and are used to fix the MEMS sensitive structure 201 on the module bracket 209;

[0056] like Figure 2As shown in (b), the lower MEMS chip 203 has the same structure as the upper MEMS chip 202, but the coating material and thickness are different. The lower MEMS chip 203 consists of a lower anchor point 2031, a lower inner cantilever beam 2033, a lower isolation frame 2034, a second outer cantilever beam group 2032, a lower mass block 2035, a reflective film 2036, a thermosensitive film 2038, a resistive film 2039, and a lower mounting aperture group 2037; the lower mass block 2035 is square and located in the center of the structure, and the reflective film 2036 is also square, with a width smaller than that of the lower mass block 2035, and is located in the center of the lower mass block 2035; the lower mass block 2035 is suspended on the lower anchor point 2031 by the second inner and outer cantilever beam groups 2033 and 2032, and the second inner and outer cantilever beam groups 2033 and 2032 are separated by the lower isolation frame 2034;

[0057] The second inner cantilever beam group 2033 includes the fifth to eighth inner cantilever beams 2033a, 2033b, 2033c, and 2033d; the second outer cantilever beam group 2032 includes the fifth to eighth inner cantilever beams 2033a, 2033b, 2033c, and 2033d; the length of the fifth to eighth inner cantilever beams 2033a, 2033b, 2033c, and 2033d is longer than the width of the lower mass block 2035, and the length of the fifth to eighth outer cantilever beams 2032a, 2032b, 2032c, and 2032d is longer than the width of the lower isolation frame 2034; the second inner and outer cantilever beam groups 2033 and 2032 are smaller than the thickness of the lower mass block 2035,

[0058] The thickness of the lower isolation frame 2034 and the lower anchor point 2031 is the same as that of the lower mass block 2035; the thermal film 2038 is composed of a rectangular thermal module 2038a and a first input and output module 2038b1 and 2038b2, and is located in the middle position above the lower anchor point 2031; the resistance film 2039 is composed of a "snake-shaped" resistance module 2039a and a second input and output module 2039b1 and 2039b2, and is located in the middle position below the lower anchor point 2031. In the case where the temperature in the package housing 1 is basically stable, the temperature of the MEMS sensitive structure 201 can be more precisely monitored and controlled; the lower mounting aperture group 2037 includes fifth to eighth circular apertures 2037a, 2037b, 2037c, and 2037d; wherein the fifth to eighth circular apertures 2037a, 2037b, 2037c, and 2037d are distributed at the four corners of the lower anchor point 2031, and are used to fix the MEMS sensitive structure 201 on the module bracket 209;

[0059] like Figure 2As shown in (c), the gasket 204 is an annular structure, which is consistent with the structure of the upper and lower anchor points 2021 and 2031, but the thickness is different. The thickness of the gasket 204 is one fifth of the thickness of the lower MEMS chip 203; the four corners of the gasket 204 are provided with ninth to twelfth circular apertures 2041a, 2041b, 2041c, and 2041d, which are used to fix the MEMS sensitive structure 201 on the module bracket 209;

[0060] like Figure 2 As shown in (d), the micro-nano grating 205 is composed of a substrate 2051 and a grating rack 2052. The substrate 2051 is a transparent material, and the area of ​​the substrate 2051 is consistent with the total area of ​​the upper and lower MEMS chips 202 and 203; the width of the grating rack 2052 is 1.5 to 2 microns, and the rack width is consistent with the gap width, that is, the duty cycle is 50%, and the thickness is 50 to 100 nanometers. The four corners of the substrate 2051 are provided with thirteenth to sixteenth circular apertures 2053a, 2053b, 2053c, and 2053d, which are used to fix the MEMS sensitive structure 201 on the module bracket 209.

[0061] like Figure 3 As shown, the module bracket 209 is a "concave" structure, wherein the lengths of the left and right fixed pages are smaller than the middle support page part, the upper and lower ends of the left fixed page are provided with the first and second screw holes 210a, 210b; the upper and lower ends of the right fixed page are provided with the third and fourth screw holes 210c, 210d, which are used to fix it to the package shell 1; the middle support page is a hollow structure, and the opening area is larger than the total area of ​​the cantilever beam part of the upper and lower MEMS chips 202, 203, the nut group 208 includes the first to fourth nuts 208a, 208b, 208c, 208d; the first screw group 207 includes the first to fourth screws 207a, 207b, 207c, 207d;

[0062] The MEMS sensitive structure 201 is fixed to the outside of the four corners of the opening by the first to fourth screws 207a, 207b, 207c, 207d and the first to fourth nuts 208a, 208b, 208c, 208d, so that the first outer and inner cantilever beam groups 2022, 2023 and the upper mass block 2025 can move freely up and down in the opening; the main body of the coil winding bracket 211 is a hollow square ring structure, and the winding shape of the coil 212 is also square. The width of the coil 212 is smaller than the width of the permanent magnetic film 2026, which is three-quarters of the width. The center of the coil 212 coincides with the center of the permanent magnetic film 2026 to ensure that the direction of the electromagnetic feedback force is perpendicular to the upper mass block 2025; the coil winding bracket 211 is fixed to the support page of the module bracket 209 by the long strip support arms on both sides thereof, and the screws and nuts 213a, 213b on both sides are located at the left and right positions of the center of the left and right support arms respectively.

[0063] like Figure 4 As shown, the area of ​​the driving circuit 306 in the laser module 3 is smaller than the area of ​​the wedge-shaped base 307, and the centers of the two coincide. The third screw group 308 includes first to fourth driving circuit screws 308a, 308b, 308c, and 308d; the driving circuit 306 is fixed on the wedge-shaped base 307 through the first to fourth driving circuit fixing screws 308a, 308b, 308c, and 308d on its four corners; the semiconductor laser 301 is located to the right of the middle of the driving circuit 306 in the horizontal direction and in the middle of the driving circuit 306 in the vertical direction; the beam splitter prism 305 is a cube and is supported by a circular hollow bracket 304 directly above the semiconductor laser 301 to ensure that the light beam can propagate along the original path; the bottom area of ​​the collimating lens 302 is smaller than the upper surface area of ​​the semiconductor laser 301 and is located in the center thereof; the first power / signal interface 310 is located to the right of the semiconductor laser 301 and is used to connect the first power / signal terminal 309.

[0064] like Figure 5 As shown, the area of ​​the power control circuit 402 in the optical power stabilization module 4 is smaller than the area of ​​the first rectangular base 403, and the centers of the two coincide. The fourth screw group includes first to fourth power control circuit fixing screws 404a, 404b, 404c, and 404d; the power control circuit 402 is fixed to the first rectangular base 403 through the first to fourth power control circuit fixing screws 404a, 404b, 404c, and 404d on its four corners; the photodetector 401 is located in the middle of the control circuit 402 both horizontally and vertically; the light sensitive chip 401a of the photodetector 401 is square and located in the center of the circular packaging tube shell 401b; the second power / signal interface 407 is located directly below the photodetector 401 and is used for the second connection power / signal terminal 406.

[0065] like Figure 6 As shown, the area of ​​the interface circuit 502 in the photoelectric detection module 5 is smaller than the area of ​​the second rectangular base 503, and the centers of the two coincide. The fifth screw group 504 includes first to fourth interface circuit fixing screws 504a, 504b, 504c, and 504d; the interface circuit 502 is fixed on the second rectangular base 503 by the first to fourth interface circuit fixing screws 504a, 504b, 504c, and 504d; the first to third photodetectors 501a, 501b, and 501c are located in the middle of the interface circuit 502 in the horizontal direction, and the second photodetectors 501a, 501b, and 501c are located in the middle of the interface circuit 502 in the horizontal direction. The electrical detector 501b is located in the middle of the interface circuit 502 in the vertical direction, and the first and third photodetectors 501a and 501c are respectively located above and below the second photodetector 501b; the first to third photodetector light sensitive chips 501a1, 501b1, 501c1 are all square and located in the center of the first to third circular packaging tube shells 501a2, 501b2, 501c2; the third power / signal interface 507 is located to the right of the second photodetector 501b, and is used to connect the third power / signal terminal 505.

[0066] like Figure 7 As shown, the area of ​​the temperature control circuit 603 in the temperature control module 6 is smaller than the area of ​​the third rectangular base 604, and the centers of the two coincide. The sixth screw group 605 includes the first to fourth temperature control circuit fixing screws 605a, 605b, 605c, and 605d. The temperature control circuit 603 is fixed on the third rectangular base 604 through the first to fourth temperature control circuit fixing screws 605a, 605b, 605c, and 605d; the thermistor 601 is located on the left side of the third rectangular base 604, and the heating / cooling plate 602 is located on the right side of the third rectangular base 604, and both are located in the middle of the third rectangular base 604 in the vertical direction; the fourth power / signal interface 607 is located on the left side of the middle of the temperature control circuit 603, flush with the thermistor 601 and the heating / cooling plate 602, and is used to connect the fourth power / signal terminal 606.

[0067] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above technical features.

Claims

1. An optical microseismometer device based on a MEMS three-dimensional interferometer, characterized in that: It comprises a packaging shell (1), a MEMS interferometer module (2), a laser module (3), an optical power stabilization module (4), a photoelectric detection module (5) and a temperature control module (6); The packaging shell (1) is a rectangular metal tube shell, comprising a coil current input / output port (101), a laser module power / signal port (102), a temperature control module power / signal port (103), and a photoelectric detection / optical power control module power / signal port (104); The MEMS interferometer module (2) comprises a MEMS sensitive structure (201), a feedback coil (212), a coil winding bracket (211), coil current input and output terminals (206a, 206b), a module bracket (209), the MEMS sensitive structure (201) is placed on the module bracket (209) and is locked and fixed by a first screw group (207) and a nut group (208), and the module bracket (209) is fixed to the packaging shell (1) by a second screw (210); wherein the MEMS The sensitive structure (201) comprises an upper MEMS chip (202), a lower MEMS chip (203), a gasket (204), and a micro-nano grating (205); wherein the upper and lower MEMS chips (202, 203) have the same cantilever beam structure, but different mass block thicknesses, the thickness of the upper MEMS chip (202) being twice that of the lower MEMS chip (203), and the upper MEMS chip (202) being bonded to the lower MEMS chip (203) in opposite directions to form a three-dimensional cantilever beam structure; The laser module (3) comprises a semiconductor laser (301), a collimating lens (302), a collimated light beam (303), a beam splitter (305), a prism bracket (304), a driving circuit (306), a wedge-shaped base (307), a first power supply / signal terminal (309), a first power supply / signal interface (310), and the driving circuit (306) is fixed to the wedge-shaped base (307) via a third screw group (308); The optical power stabilization module (4) comprises a photodetector (401), a power control circuit (402), a first rectangular base (403), a reference beam (405), a second power supply / signal terminal (406), a second power supply / signal interface (407), and the power control circuit (402) is fixed to the first rectangular base (403) via a fourth screw group (404); The photoelectric detection module (5) comprises three photoelectric detectors (501), an interface circuit (502), a second rectangular base (503), a third power supply / signal terminal (505), three diffraction light spots (506), a third power supply / signal interface (507), and the interface circuit (502) is fixed to the second rectangular base (503) via a fifth screw group (504); The temperature control module (6) comprises a thermistor (601), a heating / cooling sheet (602), a temperature control circuit (603), a third rectangular base (604), a fourth power / signal terminal (606), a fourth power / signal interface (607), and the temperature control circuit (603) is fixed to the third rectangular base (604) via a sixth screw group (605); the upper MEMS chip (202) in the MEMS interferometer module (2) is composed of an upper anchor point (2021), a first inner cantilever beam group (2023), an upper isolation frame (2024), a first outer cantilever beam group (2022), an upper mass block (2025), a permanent magnetic thin film The upper mass block (2025) is square and located at the center of the structure; the permanent magnetic film (2026) is also square and has a width smaller than that of the upper mass block (2025) and is located at the center of the upper mass block (2025); the upper mass block (2025) is suspended on an anchor point (221) by first inner and outer cantilever beam groups (2023, 2022); the first inner and outer cantilever beam groups (2023, 2022) are separated by an isolation frame (224) in the middle to avoid excessive stress concentration on the beam connection section; the first inner cantilever beam group (2023) includes first to fourth inner cantilever beams (2023a, 2023b, 2023c, 2023d); the first outer cantilever beam group (2022) includes first to fourth outer cantilever beams (2022a, 2022b, 2022c, 2022d), wherein the first inner and outer cantilever beam groups are both U-shaped structures; the length of the first to fourth inner cantilever beams (2023a, 2023b, 2023c, 2023d) is longer than the width of the upper mass block (2025), and the length of the first to fourth outer cantilever beams (2022a, 2022b, 2022c, 2022d) is longer than the width of the upper isolation frame (2024), so as to increase space utilization and maximize the elasticity of the beams; the first inner, The thickness of the outer cantilever beam group (2023, 2022) is less than the thickness of the upper mass block (2025), and the thickness of the upper isolation frame (2024) and the upper anchor point (2021) is the same as that of the upper mass block (2025), thereby obtaining a sufficiently small support stiffness; the upper mounting aperture group (2027) includes first to fourth circular apertures (2027a, 2027b, 2027c, 2027d); wherein the first to fourth circular apertures (2027a, 2027b, 2027c, 2027d) are distributed at the four corners of the upper anchor point (2021), and are used to fix the MEMS sensitive structure (201) on the module bracket (209); The lower MEMS chip (203) has the same structure as the upper MEMS chip (202), but has different coating materials and thicknesses. The lower MEMS chip (203) is composed of a lower anchor point (2031), a lower inner cantilever beam (2033), a lower isolation frame (2034), a second outer cantilever beam group (2032), a lower mass block (2035), a reflective film (2036), a thermosensitive film (2038), a resistance film (2039), and a lower mounting aperture group (2037); The lower mass block (2035) is square and located in the center of the structure; the reflective film (2036) is also square and has a width smaller than that of the lower mass block (2035) and is located in the center of the lower mass block (2035); the lower mass block (2035) is suspended on the lower anchor point (2031) by the second inner and outer cantilever beam groups (2033, 2032); the second inner and outer cantilever beam groups (2033, 2032) are separated by a lower isolation frame (2034); The second inner cantilever beam group (2033) includes fifth to eighth inner cantilever beams (2033a, 2033b, 2033c, 2033d); the second outer cantilever beam group (2032) includes fifth to eighth inner cantilever beams (2033a, 2033b, 2033c, 2033d); the length of the fifth to eighth inner cantilever beams (2033a, 2033b, 2033c, 2033d) is longer than the width of the lower mass block (2035); the length of the fifth to eighth outer cantilever beams (2032a, 2032b, 2032c, 2032d) is longer than the width of the lower isolation frame (2034); the thickness of the second inner and outer cantilever beam groups (2033, 2032) is smaller than the thickness of the lower mass block (2035); The thickness of the lower isolation frame (2034) and the lower anchor point (2031) is the same as the thickness of the lower mass block (2035); the thermal film (2038) is composed of a rectangular thermal module (2038a) and a first input and output module (2038b1, 2038b2), and is located in the middle of the upper side of the lower anchor point (2031); the resistance film (2039) is composed of a "snake-shaped" resistance module (2039a) and a second input and output module (2039b1, 2039b2), and is located in the middle of the lower side of the lower anchor point (2031). Both are used to more precisely monitor and control the temperature of the MEMS sensitive structure (201) when the temperature in the packaging shell (1) is basically stable; the lower mounting aperture group (2037) includes fifth to eighth circular apertures (2037a, 2037b, 2037c, 2037d); wherein the fifth to eighth circular apertures (2037a, 2037b, 2037c, 2037d) are distributed at the four corners of the lower anchor point (2031) and are used to fix the MEMS sensitive structure (201) on the module bracket (209); The gasket (204) is an annular structure, which is consistent with the structure of the upper and lower anchor points (2021, 2031), but has a different thickness. The thickness of the gasket (204) is one fifth of the thickness of the lower MEMS chip (203); the gasket (204) is provided with ninth to twelfth circular apertures (2041a, 2041b, 2041c, 2041d) at four corners, which are used to fix the MEMS sensitive structure (201) on the module bracket (209); The micro-nano grating (205) is composed of a substrate (2051) and a grating rack (2052); the substrate (2051) is made of a transparent material, and the area of ​​the substrate (2051) is consistent with the total area of ​​the upper and lower MEMS chips (202, 203); The width of the grating rack (2052) is 1.5 to 2 microns, the rack width is consistent with the gap width, that is, the duty cycle is 50%, and the thickness is 50 to 100 nanometers. The four corners of the substrate (2051) are provided with thirteenth to sixteenth circular apertures (2053a, 2053b, 2053c, 2053d) for fixing the MEMS sensitive structure (201) on the module bracket (209).

2. The optical microseismometer device based on MEMS three-dimensional interferometer according to claim 1, characterized in that: The module bracket (209) is a concave structure, wherein the lengths of the left and right fixed pages are smaller than the middle support page portion, the upper and lower ends of the left fixed page are provided with first and second screw apertures (210a, 210b); the upper and lower ends of the right fixed page are provided with third and fourth screw apertures (210c, 210d) for fixing it to the packaging shell (1); the middle support page is a hollow structure, the opening area is larger than the total area of ​​the cantilever beam portion of the upper and lower MEMS chips (202, 203), the nut group (208) includes first to fourth nuts (208a, 208b, 208c, 208d); the first screw group (207) includes first to fourth screws (207a, 207b, 207c, 207d); The MEMS sensitive structure (201) is fixed to the outside of the four corners of the opening by means of first to fourth screws (207a, 207b, 207c, 207d) and first to fourth nuts (208a, 208b, 208c, 208d), so that the first outer and inner cantilever beam groups (2022, 2023) and the upper mass block (2025) can freely move up and down in the opening; the main body of the coil winding support (211) is a hollow square ring structure, and the winding shape of the coil (212) is also The module is square, the width of the coil (212) is smaller than the width of the permanent magnetic film (2026), being three quarters thereof, and the center of the coil (212) coincides with the center of the permanent magnetic film (2026) to ensure that the direction of the electromagnetic feedback force is perpendicular to the upper mass block (2025); the coil winding bracket (211) is fixed to the support page of the module bracket (209) through the long strip support arms on both sides thereof, and the screws and nuts (213a, 213b) on both sides are located at the left and right positions of the center of the left and right support arms respectively.

3. The optical microseismometer device based on MEMS three-dimensional interferometer according to claim 1, characterized in that: The area of ​​the driving circuit (306) in the laser module (3) is smaller than the area of ​​the wedge-shaped base (307), and the centers of the two coincide with each other; the third screw group (308) includes first to fourth driving circuit screws (308a, 308b, 308c, 308d); the driving circuit (306) is fixed to the wedge-shaped base (307) through first to fourth driving circuit fixing screws (308a, 308b, 308c, 308d) at its four corners; the semiconductor laser (301) is located to the right of the center of the driving circuit (306) in the horizontal direction, and is located in the middle of the driving circuit (306) in the vertical direction; the beam splitter (305) is a cube, and is supported by a circular hollow bracket (304) directly above the semiconductor laser (301) to ensure that the light beam can propagate along the original path; the bottom area of ​​the collimating lens (302) is smaller than the upper surface area of ​​the semiconductor laser (301), and is located in the center thereof; The first power / signal interface (310) is located on the right side of the semiconductor laser (301) and is used to connect to the first power / signal terminal (309).

4. The optical microseismometer device based on MEMS three-dimensional interferometer according to claim 1, characterized in that: The area of ​​the power control circuit (402) in the optical power stabilization module (4) is smaller than the area of ​​the first rectangular base (403), and the centers of the two coincide with each other. The fourth screw group comprises first to fourth power control circuit fixing screws (404a, 404b, 404c, 404d); the power control circuit (402) is fixed on the first rectangular base (403) through the first to fourth power control circuit fixing screws (404a, 404b, 404c, 404d) at its four corners; the photodetector (401) is located in the middle of the control circuit (402) in both the horizontal and vertical directions; the light sensitive chip (401a) of the photodetector (401) is square and located in the center of the circular packaging tube shell (401b); and the second power supply / signal interface (407) is located directly below the photodetector (401) and is used for the second connection power supply / signal terminal (406).

5. The optical microseismometer device based on MEMS three-dimensional interferometer according to claim 1, characterized in that: The area of ​​the interface circuit (502) in the photoelectric detection module (5) is smaller than the area of ​​the second rectangular base (503), and the centers of the two coincide. The fifth screw group (504) includes first to fourth interface circuit fixing screws (504a, 504b, 504c, 504d); the interface circuit 502 is fixed on the second rectangular base (503) by the first to fourth interface circuit fixing screws (504a, 504b, 504c, 504d); the first to third photoelectric detectors (501a, 501b, 501c) are located in the middle of the interface circuit 502 in the horizontal direction, and the second photoelectric detectors (501a, 501b, 501c) are located in the middle of the interface circuit 502 in the horizontal direction. The electric detector 501b is located in the middle of the interface circuit 502 in the vertical direction, and the first and third photodetectors (501a, 501c) are respectively located above and below the second photodetector 501b; the first to third photodetector light sensitive chips (501a1, 501b1, 501c1) are all square and located in the center of the first to third circular packaging tube shells (501a2, 501b2, 501c2); the third power / signal interface (507) is located to the right of the second photodetector (501b) and is used to connect the third power / signal terminal (505).

6. The optical microseismometer device based on MEMS three-dimensional interferometer according to claim 1, characterized in that: The area of ​​the temperature control circuit (603) in the temperature control module (6) is smaller than the area of ​​the third rectangular base (604), and the centers of the two coincide with each other. The sixth screw group (605) includes first to fourth temperature control circuit fixing screws (605a, 605b, 605c, 605d), and the temperature control circuit (603) is fixed on the third rectangular base (604) through the first to fourth temperature control circuit fixing screws (605a, 605b, 605c, 605d); the thermistor (601) is located on the left side of the third rectangular base (604), and the heating / cooling plate (602) is located on the right side of the third rectangular base (604), and both are located in the middle of the third rectangular base (604) in the vertical direction; the fourth power / signal interface (607) is located on the left side of the middle of the temperature control circuit (603), flush with the thermistor (601) and the heating / cooling plate (602), and is used to connect the fourth power / signal terminal (606).

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