T-shaped decoupling vibration isolation composite beam frame structure and high-precision four-mass double-axis micro-accelerometer

Abstract

The application discloses a square-shaped decoupling vibration isolation combined beam frame structure and a high-precision four-mass double-axis micro accelerometer, and relates to the technical field of micro-electro-mechanical system (MEMS) accelerometers. The structure comprises at least four outer ring straight beam mechanisms and at least four decoupling vibration isolation rings. The accelerometer comprises a substrate layer and a device layer, wherein the device layer comprises the square-shaped decoupling vibration isolation combined beam frame structure, an X-axis double-mass sensitive unit and a Y-axis double-mass sensitive unit. The application solves the problem of cross coupling between axes in double-axis acceleration detection, realizes the isolation and vibration reduction of the MEMS accelerometer to the surrounding environment, effectively suppresses the influence of temperature and environmental vibration on the measurement accuracy of the device, adopts a cross arrangement electrode position mode, effectively suppresses the output error of the MEMS micro structure caused by process mismatch, and thus improves the output accuracy of the device. The combined mode of parallel connection of double-mass sensitive unit modules in each axis is adopted, which doubles the detection sensitivity of the device.

Description

Technical Field

[0001] This invention relates to the field of MEMS accelerometer technology, specifically to a grid-shaped decoupled vibration isolation composite beam frame structure and its high-precision four-mass biaxial micro accelerometer. Background Technology

[0002] With the continuous development of MEMS accelerometer sensing technology, its application scenarios are becoming increasingly diversified. Single-axis accelerometers can no longer meet the needs of practical applications. For example, dual-axis or even multi-axis accelerometers are needed in areas such as vehicle safety, unmanned equipment navigation, and aircraft attitude control.

[0003] Traditional, earlier dual-axis accelerometers often used two single-axis accelerometers assembled together in a board-level orthogonal configuration. This method resulted in a large dual-axis micro accelerometer with significant inter-axis crosstalk errors, and the accuracy of dual-axis detection was greatly affected by installation interference. Of course, in existing MEMS micro accelerometer products, there are also designs that use a single structure to detect acceleration in two axes simultaneously. This approach has the advantages of small size and light weight, but in application, it still suffers from output measurement errors caused by process mismatches, as well as low sensitivity and poor signal-to-noise ratio, resulting in low overall detection accuracy of the micro accelerometer device. Summary of the Invention

[0004] The main objective of this invention is to address the shortcomings of existing technologies. First, by innovatively designing a grid-shaped sensitive mass unit basic module and adopting a cross-arrangement of electrode positions, the output error caused by process mismatch in MEMS microstructures can be effectively suppressed. Second, the design of parallel combination of dual-mass sensitive unit modules in each axis will significantly improve the detection sensitivity of the device. Finally, the overall frame of the device adopts a grid-shaped decoupled vibration isolation composite beam design, which makes the four mass sensitive unit modules symmetrical about the structural center and suspended, and can move independently and collaboratively in their respective sensitive axes, thereby solving the problem of inter-axis cross-coupling in dual-axis acceleration detection. At the same time, this frame can realize the isolation and vibration reduction of the MEMS accelerometer from the surrounding environment, effectively suppressing the influence of temperature and environmental vibration on the measurement accuracy of the device. Ultimately, a grid-shaped decoupled vibration isolation composite beam frame structure and its high-precision four-mass dual-axis micro accelerometer are obtained.

[0005] To achieve the above objectives, one of the technical solutions adopted by the present invention is: a grid-shaped decoupling and vibration isolation composite beam frame structure, which includes:

[0006] At least four outer ring straight beam mechanisms 1 and at least four decoupled vibration isolation rings 2 work together to isolate and reduce vibration from the surrounding environment, effectively suppressing temperature and environmental vibrations;

[0007] Each of the outer ring straight beam mechanisms 1 is symmetric about the center of the structure, forming a cross shape, and is mounted on the substrate layer;

[0008] Each of the decoupling vibration isolation rings 2 is mounted in the corresponding outer ring straight beam mechanism 1, so that the sensitive unit mounted on the structure is symmetric about the center of the structure and is suspended, so that the sensitive unit independently cooperates in movement in the respective sensitive axis, avoiding cross coupling between axes in biaxial acceleration detection.

[0009] Further, each of the outer ring straight beam mechanisms 1 includes eight straight beams 101; the eight straight beams 101 are connected two by two to form an L shape, located at the four corners of the outer ring straight beam mechanism 1.

[0010] Further, two straight beams 101 located at the four corners of the substrate layer are fixedly mounted on the substrate layer through a single-mass fixed anchor point 102;

[0011] Four straight beams 101 located at the centers of the four edges of the substrate layer are fixedly mounted on the substrate layer through a double-mass fixed anchor point 103;

[0012] Eight straight beams 101 located at the center of the substrate layer are fixedly mounted on the substrate layer through a four-mass fixed anchor point 104.

[0013] Further, the five edges of each of the decoupling vibration isolation rings 2 are connected to the eight straight beams 101 of the corresponding outer ring straight beam mechanism 1, respectively.

[0014] To achieve the above object, one of the technical solutions adopted by the present application is: a high-precision four-mass biaxial micro-accelerometer, which is used for detecting the acceleration of a navigation device, and the accelerometer comprises:

[0015] The substrate layer 3 is made of silicon;

[0016] The device layer 4 is located above the substrate layer 3 and is fixedly mounted on the substrate layer 3 through corresponding anchors;

[0017] The device layer 4 includes the above-mentioned cross-shaped decoupling vibration isolation combined beam frame structure, the X-axis double-mass sensitive unit 5, and the Y-axis double-mass sensitive unit 6.

[0018] The X-axis double-mass sensitive unit 5 is mounted in the upper half of the cross-shaped decoupling vibration isolation combined beam frame structure, and the Y-axis double-mass sensitive unit 6 is mounted in the lower half of the cross-shaped decoupling vibration isolation combined beam frame structure;

[0019] When there is an acceleration input along the X-axis, the X-axis dual-mass sensitive unit 5 will displace in the X-axis direction, and the X-axis dual-mass sensitive unit 5 will generate a capacitance change, which is read out by the control of the peripheral circuit to complete the detection of the X-axis acceleration, and the Y-axis dual-mass sensitive unit 6 has a zero capacitance and no signal output in the Y-axis direction, which will not be disturbed by the X-axis input and remain in the zero position.

[0020] When there is an acceleration input along the Y-axis, the Y-axis dual-mass sensitive unit 6 will displace in the Y-axis direction, and the Y-axis dual-mass sensitive unit 6 will generate a capacitance change, which is read out by the control of the peripheral circuit to complete the detection of the Y-axis acceleration, and the X-axis dual-mass sensitive unit 5 has a zero capacitance and no signal output in the X-axis direction, which will not be disturbed by the Y-axis input and remain in the zero position.

[0021] Further, the X-axis dual-mass sensitive unit 5 comprises:

[0022] At least two X-axis H-shaped single-mass comb tooth frames 501, two X-axis H-shaped single-mass comb tooth frames 501 are respectively located in the two outer ring straight beam mechanisms 1 of the upper half part;

[0023] At least eight X-axis folding beams 502; each X-axis H-shaped single-mass comb tooth frame 501 is connected to the decoupling and vibration isolation ring 2 of the corresponding outer ring straight beam mechanism 1 along the X-axis direction through the X-axis folding beam 502;

[0024] An X-axis dual-mass H-shaped connector 503 is used to connect the adjacent four X-axis folding beams 502 to connect the two X-axis H-shaped single-mass comb tooth frames 501.

[0025] At least four X-axis positive detection fixed comb tooth frames 504; one end of each X-axis positive detection fixed comb tooth frame 504 is fixedly installed on the scale bottom layer 3 through an X-axis positive detection fixed anchor point 505, and the other end is suspended; each X-axis positive detection fixed comb tooth frame 504 is located in the X-axis H-shaped single-mass comb tooth frame 501;

[0026] A plurality of X-axis positive detection fixed combs 506, each X-axis positive detection fixed comb 506 is installed on the X-axis positive detection fixed comb tooth frame 504;

[0027] At least four X-axis negative detection fixed comb tooth frames 507; one end of each X-axis negative detection fixed comb tooth frame 507 is fixedly installed on the scale bottom layer 3 through an X-axis negative detection fixed anchor point 510, and the other end is suspended; each X-axis negative detection fixed comb tooth frame 507 is located in the X-axis H-shaped single-mass comb tooth frame 501;

[0028] A plurality of X-axis negative detection fixed comb teeth 508, each of which is mounted on the X-axis negative detection fixed comb tooth frame 507;

[0029] A plurality of X-axis detection movable comb teeth 509, each of which is mounted on the X-axis T-shaped single-mass comb tooth frame 501;

[0030] Among them, the X-axis positive detection fixed comb teeth 506 and the X-axis detection movable comb teeth 509 are arranged in each other;

[0031] The X-axis negative detection fixed comb teeth 508 and the X-axis detection movable comb teeth 509 are arranged in each other.

[0032] Further, the X-axis folding beam 502 is driven to move along the X-axis by the external X-axis acceleration, which drives the X-axis T-shaped single-mass comb tooth frame 501 to move along the X-axis, and further drives the X-axis detection movable comb teeth 509 to move along the X-axis, and the X-axis detection movable comb teeth 509 are respectively arranged in each other with each X-axis positive detection fixed comb teeth 506 、 The X-axis negative detection fixed comb teeth 508 generate differential capacitance changes between them, and the values are read out by the control of the peripheral circuit.

[0033] Further, the Y-axis double-mass sensitive unit 6 comprises:

[0034] At least two Y-axis T-shaped single-mass comb tooth frames 601, two of which are respectively located in the two outer ring straight beam mechanisms 1 of the lower half;

[0035] At least eight Y-axis folding beams 602; each Y-axis T-shaped single-mass comb tooth frame 601 is connected to the decoupling vibration isolation ring 2 of the corresponding outer ring straight beam mechanism 1 along the Y-axis through the Y-axis folding beam 602;

[0036] A Y-axis double-mass H-shaped connector 603 is used to connect the adjacent four Y-axis folding beams 602, so as to connect the two Y-axis T-shaped single-mass comb tooth frames 601.

[0037] At least four Y-axis positive detection fixed comb tooth frames 604; one end of each Y-axis positive detection fixed comb tooth frame 604 is fixedly mounted on the scale bottom layer through a Y-axis positive detection fixed anchor point 605, and the other end is suspended; each Y-axis positive detection fixed comb tooth frame 604 is located in the Y-axis T-shaped single-mass comb tooth frame 601;

[0038] A plurality of Y-axis positive detection fixed comb teeth 606, each of which is mounted on the Y-axis positive detection fixed comb tooth frame 604;

[0039] At least four Y-axis negative detection fixed comb tooth frames 607, one end of each Y-axis negative detection fixed comb tooth frame 607 is fixedly installed on the scale bottom layer through a Y-axis negative detection fixed anchor point 610, and the other end is suspended, and each Y-axis negative detection fixed comb tooth frame 607 is located in the Y-axis single-mass T-shaped comb tooth frame 601;

[0040] A plurality of Y-axis negative detection fixed combs 608, each of the Y-axis negative detection fixed combs 608 is installed on the Y-axis negative detection fixed comb tooth frame 607;

[0041] A plurality of Y-axis detection movable tooth combs 609, each of the Y-axis detection movable tooth combs 609 is installed on the Y-axis single-mass T-shaped comb tooth frame 601;

[0042] Wherein, the Y-axis positive detection fixed comb tooth 606 and the Y-axis detection movable tooth comb 609 are arranged in interpenetration;

[0043] The Y-axis negative detection fixed comb tooth 608 and the Y-axis detection movable tooth comb 609 are arranged in interpenetration.

[0044] Further, the Y-axis folding beam 602 is driven to move along the Y-axis by external Y-axis acceleration, drives the Y-axis single-mass T-shaped comb tooth frame 601 to move along the Y-axis, and then drives the Y-axis detection movable tooth comb 609 to move along the Y-axis, the Y-axis detection movable tooth comb 609 is respectively arranged in interpenetration with each Y-axis positive detection fixed comb tooth 606 、 The Y-axis negative detection fixed comb tooth 608 generates differential capacitance change, and the value is read out through the control of the peripheral circuit.

[0045] Compared with the prior art, the application has the following beneficial effects:

[0046] 1. The application can solve the cross-coupling problem between the two axes of the acceleration detection, and can realize the isolation and vibration reduction of the surrounding environment of the MEMS accelerometer, effectively suppress the influence of temperature and environmental vibration on the measurement accuracy of the device;

[0047] 2. The cross-arranged electrode position mode can effectively suppress the output error of the MEMS microstructure caused by process mismatch, thereby improving the output accuracy of the device;

[0048] 3. The combination mode of parallel connection of the double-mass sensitive unit modules in each axis can double the detection sensitivity of the device and further enhance the signal-to-noise ratio of the device;

[0049] 4. The device has high measurement accuracy, small size, easy-to-process overall structure, can be mass-produced, and has low cost. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 It is a structural schematic view of the T-shaped decoupling vibration isolation combined beam frame structure of the application;

[0051] Figure 2 Structure diagram of high-precision four-mass double-axis micro-accelerometer of the present application;

[0052] Figure 3 Structure diagram of X-axis single-mass T-shaped comb tooth frame of the present application;

[0053] Figure 4 Structure diagram of Y-axis single-mass T-shaped comb tooth frame of the present application;

[0054] Figure 5 Structure diagram of X-axis double-mass sensitive unit of the present application;

[0055] Figure 6 Structure diagram of Y-axis double-mass sensitive unit of the present application.

[0056] In the figure: 1, outer ring straight beam mechanism; 101, straight beam; 102, single-mass fixed anchor point; 103, double-mass fixed anchor point; 104, four-mass fixed anchor point;

[0057] 2, decoupling vibration isolation ring;

[0058] 3, substrate layer;

[0059] 4, device layer;

[0060] 5, X-axis double-mass sensitive unit; 501, X-axis single-mass T-shaped comb tooth frame; 502, X-axis foldable beam; 503, X-axis double-mass H-shaped connector; 504, X-axis positive detection fixed comb tooth frame; 505, X-axis positive detection fixed anchor point; 506, X-axis positive detection fixed comb tooth; 507, X-axis negative detection fixed comb tooth frame; 508, X-axis negative detection fixed comb tooth; 509, X-axis detection movable tooth comb; 510, X-axis negative detection fixed anchor point;

[0061] 6, Y-axis double-mass sensitive unit; 601, Y-axis single-mass T-shaped comb tooth frame; 602, Y-axis foldable beam; 603, Y-axis double-mass H-shaped connector; 604, Y-axis positive detection fixed comb tooth frame; 605, Y-axis positive detection fixed anchor point; 606, Y-axis positive detection fixed comb tooth; 607, Y-axis negative detection fixed comb tooth frame; 608, Y-axis negative detection fixed comb tooth; 609, Y-axis detection movable tooth comb; 610, Y-axis negative detection fixed anchor point. DETAILED DESCRIPTION

[0062] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below with reference to the accompanying drawings.

[0063] Example 1

[0064] AsFigure 1 As shown in the figure, the structure includes:

[0065] The at least four outer ring straight beam mechanisms 1 and the at least four decoupling vibration isolation rings 2 jointly function to isolate and reduce vibration from the surrounding environment, effectively suppressing temperature and environmental vibration;

[0066] Each of the four outer ring straight beam mechanisms 1 is symmetric about the center of the structure, forming a square, and is mounted on the substrate layer;

[0067] Specifically, each of the outer ring straight beam mechanisms 1 includes eight straight beams 101; two of the eight straight beams 101 are connected to form an L shape at each of the four corners of the outer ring straight beam mechanism 1.

[0068] Specifically, two straight beams 101 located at the four corners of the substrate layer are fixedly mounted on the substrate layer through a single-mass fixed anchor point 102;

[0069] Four straight beams 101 located at the centers of the four sides of the substrate layer are fixedly mounted on the substrate layer through a double-mass fixed anchor point 103;

[0070] Eight straight beams 101 located at the center of the substrate layer are fixedly mounted on the substrate layer through a four-mass fixed anchor point 104.

[0071] Each of the decoupling vibration isolation rings 2 is mounted in the corresponding outer ring straight beam mechanism 1, so that the sensitive units mounted on the structure are symmetric about the center of the structure and are suspended, allowing the sensitive units to move independently and cooperatively in the respective sensitive axes, avoiding cross-coupling between axes in dual-axis acceleration detection.

[0072] Specifically, the five edges of each of the decoupling vibration isolation rings 2 are connected to the eight straight beams 101 of the corresponding outer ring straight beam mechanism 1.

[0073] Embodiment 2

[0074] As shown in the figure, a high-precision four-mass dual-axis micro-accelerometer for detecting acceleration of a navigation device, the accelerometer comprising: Figures 2-6

[0075] A substrate layer 3 made of silicon;

[0076] A device layer 4 located above the substrate layer 3 and fixedly mounted on the substrate layer 3 through corresponding anchors;

[0077] The device layer 4 includes the square decoupling vibration isolation combined beam frame structure, the X-axis dual-mass sensitive unit 5, and the Y-axis dual-mass sensitive unit 6 as described in Embodiment 1;

[0078] ​The X-axis double-mass sensitive unit 5 is installed in the upper half of the field-shaped decoupling vibration isolation combined beam frame structure, and the Y-axis double-mass sensitive unit 6 is installed in the lower half of the field-shaped decoupling vibration isolation combined beam frame structure.

[0079] As shown in Figure 5 , specifically, the X-axis double-mass sensitive unit 5 comprises:

[0080] As shown in Figure 3 , at least two X-axis field-shaped single-mass comb tooth frames 501 are respectively located in the two outer ring straight beam mechanisms 1 of the upper half;

[0081] At least eight X-axis folding beams 502; each X-axis field-shaped single-mass comb tooth frame 501 is connected to the decoupling vibration isolation ring 2 of the corresponding outer ring straight beam mechanism 1 along the X-axis through the X-axis folding beam 502;

[0082] Specifically, the four square holes thereof are symmetric about the single-mass base module center, detection comb teeth are uniformly distributed on the tooth combs inside the four square holes during design, and positive and negative electrode cross arrangement is performed according to the corresponding comb tooth electrodes, so that the output error of the MEMS microstructure caused by process mismatch can be effectively suppressed, thereby optimizing the output precision of the device.

[0083] The X-axis double-mass I-shaped connector 503 is used for connecting the adjacent four X-axis folding beams 502, so as to connect the two X-axis field-shaped single-mass comb tooth frames 501.

[0084] At least four X-axis positive detection fixed comb tooth frames 504; one end of each X-axis positive detection fixed comb tooth frame 504 is fixedly installed on the scale bottom layer 3 through an X-axis positive detection fixed anchor point 505, and the other end is suspended; each X-axis positive detection fixed comb tooth frame 504 is located in the X-axis field-shaped single-mass comb tooth frame 501;

[0085] A plurality of X-axis positive detection fixed combs 506 are provided, and each X-axis positive detection fixed comb 506 is installed on the X-axis positive detection fixed comb tooth frame 504;

[0086] At least four X-axis negative detection fixed comb tooth frames 507; one end of each X-axis negative detection fixed comb tooth frame 507 is fixedly installed on the scale bottom layer 3 through an X-axis negative detection fixed anchor point 510, and the other end is suspended; each X-axis negative detection fixed comb tooth frame 507 is located in the X-axis field-shaped single-mass comb tooth frame 501;

[0087] A plurality of X-axis negative detection fixed combs 508 are provided, and each X-axis negative detection fixed comb 508 is installed on the X-axis negative detection fixed comb tooth frame 507;

[0088] A plurality of X-axis detection movable comb teeth 509, each of which is mounted on the X-axis cross-shaped single-mass comb teeth frame 501;

[0089] Among them, the X-axis positive detection fixed comb teeth 506 and the X-axis detection movable comb teeth 509 are arranged in each other.

[0090] The X-axis negative detection fixed comb teeth 508 and the X-axis detection movable comb teeth 509 are arranged in each other.

[0091] Specifically, one of the X-axis positive detection fixed comb teeth 506 and one of the X-axis detection movable comb teeth 509 form a pair of positive detection capacitors, and there are N pairs, and the X-axis positive detection electrode is composed of N pairs of positive detection capacitors; one of the X-axis negative detection fixed comb teeth 508 and one of the X-axis detection movable comb teeth 509 form a pair of negative detection capacitors, and there are N pairs, and the X-axis negative detection electrode is composed of N pairs of positive detection capacitors; through the parallel combination design, the acceleration detection sensitivity of the device X-axis is doubled.

[0092] Of course, there are many ways to detect acceleration by using comb teeth differential capacitors, including open-loop detection, closed-loop detection, and increasing separate detection feedback electrodes.

[0093] As shown in Figure 6 Specifically, the Y-axis double-mass sensitive unit 6 includes:

[0094] As shown in Figure 4 At least two Y-axis cross-shaped single-mass comb teeth frames 601, two of which are located in the two outer ring straight beam mechanisms 1 of the lower half;

[0095] At least eight Y-axis folding beams 602; each Y-axis cross-shaped single-mass comb teeth frame 601 is connected to the decoupling vibration isolation ring 2 of the corresponding outer ring straight beam mechanism 1 along the Y-axis through the Y-axis folding beam 602;

[0096] Specifically, the four square holes are symmetric about the single-mass base module center, and detection combs are uniformly distributed on the combs inside the four square holes during design, and positive and negative electrode cross arrangement is performed according to the corresponding comb electrodes, which can effectively suppress the output error of the MEMS microstructure caused by process mismatch, thereby optimizing the output precision of the device.

[0097] The Y-axis double-mass H-shaped connector 603 is used to connect the adjacent four Y-axis folding beams 602, so as to connect the two Y-axis cross-shaped single-mass comb teeth frames 601.

[0098] At least four Y-axis positive detection fixed comb tooth frames 604; one end of each Y-axis positive detection fixed comb tooth frame 604 is fixedly installed on the scale bottom layer through a Y-axis positive detection fixed anchor point 605, and the other end is suspended; each Y-axis positive detection fixed comb tooth frame 604 is located in the Y-axis single-mass T-shaped comb tooth frame 601;

[0099] A plurality of Y-axis positive detection fixed combs 606, each of which is installed on the Y-axis positive detection fixed comb tooth frame 604;

[0100] At least four Y-axis negative detection fixed comb tooth frames 607; one end of each Y-axis negative detection fixed comb tooth frame 607 is fixedly installed on the scale bottom layer through a Y-axis negative detection fixed anchor point 610, and the other end is suspended; each Y-axis negative detection fixed comb tooth frame 607 is located in the Y-axis single-mass T-shaped comb tooth frame 601;

[0101] A plurality of Y-axis negative detection fixed combs 608, each of which is installed on the Y-axis negative detection fixed comb tooth frame 607;

[0102] A plurality of Y-axis detection movable tooth combs 609, each of which is installed on the Y-axis single-mass T-shaped comb tooth frame 601;

[0103] Among them, the Y-axis positive detection fixed comb 606 and the Y-axis detection movable tooth comb 609 are arranged in interpenetration;

[0104] The Y-axis negative detection fixed comb 608 and the Y-axis detection movable tooth comb 609 are arranged in interpenetration.

[0105] Specifically, one Y-axis positive detection fixed comb 606 and one Y-axis detection movable tooth comb 609 form a pair of positive detection capacitors, and there are N pairs, and the Y-axis positive detection electrode is composed of N pairs of positive detection capacitors; one Y-axis negative detection fixed comb 608 and one Y-axis detection movable tooth comb 609 form a pair of negative detection capacitors, and there are N pairs, and the Y-axis negative detection electrode is composed of N pairs of negative detection capacitors; through the parallel combination design, the acceleration detection sensitivity of the device Y-axis is multiplied.

[0106] Of course, there are many ways to detect acceleration by using comb differential capacitors, including open-loop detection, closed-loop detection, and increasing separate detection feedback electrodes.

[0107] Its working process: when there is an acceleration input along the X axis, the X axis double mass sensitive unit 5 will displace in the X axis direction, the X axis double mass sensitive unit 5 will generate a capacitance change, through the control reading of the peripheral circuit, the detection of the X axis acceleration is completed, and through the decoupling vibration isolation combined beam frame structure, the Y axis double mass sensitive unit 6 capacitance is zero, the Y axis has no signal output, and will not be disturbed by the X axis input and keep in the zero position;

[0108] Specifically, the X axis folding beam 502 is driven to move along the X axis by the external X axis acceleration, the X axis single mass comb tooth frame 501 is driven to move along the X axis, and the X axis detection movable tooth comb 509 is driven to move along the X axis, the X axis detection movable tooth comb 509 is respectively arranged between each X axis positive detection fixed comb tooth 506 、 The X axis negative detection fixed comb tooth 508 generates a differential capacitance change, and the value is read out through the control of the peripheral circuit.

[0109] When there is an acceleration input along the Y axis, the Y axis double mass sensitive unit 6 will displace in the Y axis direction, the Y axis double mass sensitive unit 6 will generate a capacitance change, through the control reading of the peripheral circuit, the detection of the Y axis acceleration is completed, and through the decoupling vibration isolation combined beam frame structure, the X axis double mass sensitive unit 5 capacitance is zero, the X axis has no signal output, and will not be disturbed by the Y axis input and keep in the zero position.

[0110] Specifically, the X axis folding beam 502 is driven to move along the X axis by the external X axis acceleration, the X axis single mass comb tooth frame 501 is driven to move along the X axis, and the X axis detection movable tooth comb 509 is driven to move along the X axis, the X axis detection movable tooth comb 509 is respectively arranged between each X axis positive detection fixed comb tooth 506 、 The X axis negative detection fixed comb tooth 508 generates a differential capacitance change, and the value is read out through the control of the peripheral circuit.

[0111] The basic principle, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the present application is not limited to the above examples, the above examples and descriptions in the specification are only preferred examples of the present application, and are not intended to limit the present application, various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A high-precision four-mass biaxial micro accelerometer, used for detecting the acceleration of navigation devices, characterized in that, The accelerometer includes: The substrate (3) is made of silicon; Device layer (4) is located above substrate layer (3) and is fixedly mounted on substrate layer (3) by corresponding anchoring; Among them, the device layer (4) includes a grid-shaped decoupled vibration isolation composite beam frame structure, an X-axis dual mass sensitive unit (5), and a Y-axis dual mass sensitive unit (6); The grid-shaped decoupled vibration isolation combined beam frame structure includes at least four outer ring straight beam mechanisms (1) and at least four decoupled vibration isolation rings (2), which work together to isolate and reduce vibration from the surrounding environment, effectively suppressing temperature and environmental vibrations; Each of the four outer ring straight beam mechanisms (1) is symmetrical about the center of the structure, forming a grid shape, and is mounted on the substrate layer; Each of the decoupling vibration isolation rings (2) is installed in the corresponding outer ring straight beam mechanism (1), so that the sensitive unit installed on the structure is symmetrical about the center of the structure and suspended, so that the sensitive unit moves independently and collaboratively in its own sensitive axis, avoiding the cross coupling between axes of dual-axis acceleration detection; Each of the outer ring straight beam mechanisms (1) includes eight straight beams (101); the eight straight beams (101) are connected in pairs to form an L-shape, located at the four corners of the outer ring straight beam mechanism (1); Two straight beams (101) located at the four corners of the substrate are fixedly installed on the substrate by single-mass fixed anchor points (102); Four straight beams (101) located at the center of the four sides of the substrate are fixedly installed on the substrate by double mass fixing anchors (103); Eight straight beams (101) located at the center of the substrate are fixedly mounted on the substrate by four mass anchor points (104); Each of the five sides of the decoupling vibration isolation ring (2) is connected to the eight straight beams (101) of the corresponding outer ring straight beam mechanism (1); The X-axis dual mass sensitive unit (5) is installed in the upper half of the grid-shaped decoupled vibration isolation composite beam frame structure, and the Y-axis dual mass sensitive unit (6) is installed in the lower half of the grid-shaped decoupled vibration isolation composite beam frame structure. When there is an external acceleration input along the X-axis, the X-axis dual mass sensing unit (5) will be displaced in the X-axis direction, and the X-axis dual mass sensing unit (5) will generate a capacitance change. The X-axis acceleration is detected by the control of the peripheral circuit. Furthermore, through the grid-shaped decoupling and vibration isolation combined beam frame structure, the capacitance of the Y-axis dual mass sensing unit (6) is zero, and there is no signal output in the Y-axis direction. It will not be disturbed by the X-axis input and will remain in the zero position. When there is an external acceleration input along the Y-axis, the Y-axis dual mass sensing unit (6) will be displaced in the Y-axis direction, and the Y-axis dual mass sensing unit (6) will generate a capacitance change. The Y-axis acceleration is detected by the control of the peripheral circuit. Furthermore, through the grid-shaped decoupling and vibration isolation combined beam frame structure, the capacitance of the X-axis dual mass sensing unit (5) is zero, and there is no signal output in the X-axis direction. It will not be disturbed by the Y-axis input and will remain in the zero position.

2. The high-precision four-mass biaxial micro accelerometer according to claim 1, characterized in that, The X-axis dual mass sensing unit (5) includes: At least two X-axis grid-shaped single-mass comb frames (501), the two X-axis grid-shaped single-mass comb frames (501) are respectively located in the two outer ring straight beam mechanisms (1) in the upper half; At least eight X-axis folding beams (502); each X-axis grid-shaped single-mass comb frame (501) is connected along the X-axis to the decoupling vibration isolation ring (2) of the corresponding outer ring straight beam mechanism (1) through the X-axis folding beam (502); X-axis dual-mass I-beam connector (503) is used to connect four adjacent X-axis folding beams (502) to connect two X-axis grid-shaped single-mass comb frames (501); At least four X-axis positive detection fixed comb frames (504); one end of each X-axis positive detection fixed comb frame (504) is fixedly installed on the weighing bottom layer (3) through X-axis positive detection fixed anchor point (505), and the other end is suspended; each X-axis positive detection fixed comb frame (504) is located inside the X-axis grid-shaped single mass comb frame (501); Multiple X-axis positive detection fixed comb teeth (506), each of the X-axis positive detection fixed comb teeth (506) is mounted on an X-axis positive detection fixed comb tooth frame (504); At least four X-axis negative detection fixed comb frames (507); one end of each X-axis negative detection fixed comb frame (507) is fixedly installed on the weighing bottom layer (3) through X-axis negative detection fixed anchor point (510), and the other end is suspended; each X-axis negative detection fixed comb frame (507) is located inside the X-axis grid-shaped single mass comb frame (501); Multiple X-axis negative detection fixed comb teeth (508), each of the X-axis negative detection fixed comb teeth (508) is mounted on an X-axis negative detection fixed comb tooth frame (507); Multiple X-axis detection movable toothed combs (509), each of the X-axis detection movable toothed combs (509) is mounted on an X-axis grid-shaped single-mass comb tooth frame (501); Among them, the X-axis positive detection fixed comb teeth (506) and the X-axis detection movable comb teeth (509) are interleaved; The X-axis negative detection fixed comb teeth (508) and the X-axis detection movable comb teeth (509) are interleaved.

3. The high-precision four-mass biaxial micro-accelerometer according to claim 2, characterized in that, The X-axis folding beam (502) is driven by external X-axis acceleration to move along the X-axis, which in turn drives the X-axis grid-shaped single-mass comb frame (501) to move along the X-axis, thereby driving the X-axis detection movable comb (509) to move along the X-axis. The X-axis detection movable comb (509) generates differential capacitance changes with each X-axis positive detection fixed comb tooth (506) and X-axis negative detection fixed comb tooth (508), and the values ​​are read out by the control of the peripheral circuit.

4. The high-precision four-mass biaxial micro accelerometer according to claim 1, characterized in that, The Y-axis dual mass sensing unit (6) includes: At least two Y-axis grid-shaped single-mass comb frames (601), the two Y-axis grid-shaped single-mass comb frames (601) are respectively located in the two outer ring straight beam mechanisms (1) in the lower half; At least eight Y-axis folding beams (602); each Y-axis grid-shaped single-mass comb frame (601) is connected along the Y-axis to the decoupling vibration isolation ring (2) of the corresponding outer ring straight beam mechanism (1) through the Y-axis folding beam (602); Y-axis dual-mass I-beam connector (603) is used to connect four adjacent Y-axis folding beams (602) to connect two Y-axis grid-shaped single-mass comb frames (601); At least four Y-axis positive detection fixed comb frames (604); one end of each Y-axis positive detection fixed comb frame (604) is fixedly installed on the weighing bottom layer (3) through a Y-axis positive detection fixed anchor point (605), and the other end is suspended; each Y-axis positive detection fixed comb frame (604) is located inside the Y-axis grid-shaped single mass comb frame (601); Multiple Y-axis positive detection fixed comb teeth (606), each of the Y-axis positive detection fixed comb teeth (606) is mounted on a Y-axis positive detection fixed comb tooth frame (604); At least four Y-axis negative detection fixed comb frames (607); one end of each Y-axis negative detection fixed comb frame (607) is fixedly installed on the weighing bottom layer (3) through the Y-axis negative detection fixed anchor point (610), and the other end is suspended; each Y-axis negative detection fixed comb frame (607) is located inside the Y-axis grid-shaped single mass comb frame (601); Multiple Y-axis negative detection fixed comb teeth (608), each of the Y-axis negative detection fixed comb teeth (608) is mounted on a Y-axis negative detection fixed comb tooth frame (607); Multiple Y-axis detection movable toothed combs (609), each of the Y-axis detection movable toothed combs (609) is mounted on a Y-axis grid-shaped single-mass comb tooth frame (601); Among them, the Y-axis positive detection fixed comb teeth (606) and the Y-axis detection movable comb teeth (609) are interleaved; The Y-axis negative detection fixed comb (608) and the Y-axis detection movable comb (609) are interleaved.

5. The high-precision four-mass biaxial micro-accelerometer according to claim 4, characterized in that, The Y-axis folding beam (602) is driven by external Y-axis acceleration to move along the Y-axis, which in turn drives the Y-axis grid-shaped single-mass comb frame (601) to move along the Y-axis, thereby driving the Y-axis detection movable comb (609) to move along the Y-axis. The Y-axis detection movable comb (609) generates differential capacitance changes with each Y-axis positive detection fixed comb tooth (606) and Y-axis negative detection fixed comb tooth (608), and the values ​​are read out by the control of the peripheral circuit.

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