MEMS accelerometers

Abstract

The present invention provides a micro-electromechanical system accelerometer, comprising: a proof mass, at least one pair of oppositely arranged seesaw structures, and an out-of-plane displacement detection assembly, wherein the out-of-plane displacement detection assembly is used to detect the rotation of the seesaw structure or the out-of-plane linear motion of the proof mass; wherein each two oppositely arranged seesaw structures are coupled to each other on a first side via a first coupling structure, and the second sides of the two seesaw structures coupled by the first coupling structure are connected to the proof mass via a second coupling structure, and the first coupling structure and the second coupling structure are both elastic coupling structures. The present invention is beneficial for improving the linearity of capacitive displacement detection and is beneficial for other non-capacitive detection methods. At the same time, the dual coupling structure is adopted to suppress the remaining translational and rotational modes of the seesaw structure.

Description

Technical field

[0001] The present invention relates to the field of micro-electromechanical systems, and in particular to a micro-electromechanical system accelerometer. [Background Technology]

[0002] Traditional out-of-plane acceleration sensors use a seesaw structure to test out-of-plane displacement. Figure 1 As shown, the seesaw structure includes an anchor point, a torsion spring, an out-of-plane detection plate, and a proof mass. Under acceleration, the asymmetric proof mass M1 drives the torsion spring to rotate along the axis formed by the torsion spring and the anchor point. Capacitive detection plates are positioned above or below the structure, forming a differential capacitance. Acceleration changes are detected by detecting changes in capacitance.

[0003] like Figure 2 As shown, since the structure is asymmetric, the seesaw structure will swing in the X direction under the action of the X direction acceleration.

[0004] To address the above issues, Murata's patent application (US20200018777A) discloses a structure using two seesaws. The main body of the rotating test mass is on the seesaw structure, and a rigid body is added to the outside as a coupling structure. As a linear mass, when out-of-plane acceleration acts, the linear mass moves linearly in the out-of-plane direction. This structure places the detection plate at a distance from the rotation axis, ensuring the gain of the capacitance change from rotation and eliminating the swing in the X direction (IP1 direction). However, it cannot suppress the rotation of the two seesaws in the same direction around the Z axis (OP) and the rotation in the same direction around the X axis (IP1 axis).

[0005] ADI's patent application (US20200132716A1) discloses a multi-axis accelerometer whose out-of-plane accelerometer uses a butterfly structure. This structure uses an inner coupling structure to achieve kinematic coupling between two seesaw structures, suppressing both in-plane rotation of a single seesaw structure and unidirectional rotation around the axis of rotation. Compared to Murata's structure, it lacks a linear proof mass for linear motion along the Z axis as an outer coupling structure, resulting in a poorer suppression of the two seesaw structures' opposing motion around the Z axis. [Summary of the invention]

[0006] An object of the present invention is to provide a micro-electromechanical system accelerometer to solve at least one of the above technical problems.

[0007] To achieve the above objectives, the present invention provides a micro-electromechanical system accelerometer comprising: a proof mass, at least one pair of oppositely arranged seesaw structures, a substrate, and an out-of-plane displacement detection assembly, wherein the seesaw structures are fixedly connected to the substrate via anchor points, and the out-of-plane displacement detection assembly is used to detect the rotation of the seesaw structures or the out-of-plane linear motion of the proof mass;

[0008] Among them, each two relatively arranged seesaw structures are coupled and connected on the first side through a first coupling structure, and a second coupling structure is provided on the second side of the two seesaw structures coupled by the first coupling structure. The first coupling structure and / or the second coupling structure are connected to the inspection mass, and the first coupling structure and the second coupling structure are both elastic coupling structures.

[0009] Preferably, only the first coupling structure or only the second coupling structure is connected to the proof mass.

[0010] Preferably, each pair of relatively arranged seesaw structures includes a first seesaw structure and a second seesaw structure, the first seesaw structure including: a first anchor point fixed to the base, a first elastic torsion spring fixed on the first anchor point, and a first connecting beam relatively arranged on both sides of the first elastic torsion spring, the first end of the first connecting beam on the side away from the first coupling structure is connected to the first elastic torsion spring, and the second end is connected to one second coupling structure; the second seesaw structure includes: a second anchor point fixed to the base at one end, a second elastic torsion spring fixed on the other end of the second anchor point, and a second connecting beam relatively arranged on both sides of the second elastic torsion spring, the first end of the second connecting beam on the side away from the first coupling mechanism is connected to the second elastic torsion spring, and the second end is connected to another second coupling structure, and the second coupling structure is connected to the inspection mass.

[0011] Preferably, each pair of relatively arranged seesaw structures includes a first seesaw structure and a second seesaw structure, the first seesaw structure including: a first anchor point fixed to the base, a first elastic torsion spring fixed on the first anchor point, and a first electrode plate setting portion A and a first electrode plate setting portion B relatively arranged on both sides of the first elastic torsion spring, the first electrode plate setting portion A and the first electrode plate setting portion B on both sides are respectively connected to the first elastic torsion spring through a first connecting beam, the out-of-plane displacement detection assembly includes a first out-of-plane detection electrode plate A and a first out-of-plane detection electrode plate B arranged on the first electrode plate setting portion A and the first electrode plate setting portion B; the second seesaw structure includes: a second anchor point fixed to the base, a second elastic torsion spring fixed on the second anchor point, and a second electrode plate setting portion A and a second electrode plate setting portion B relatively arranged on both sides of the second elastic torsion spring, the second electrode plate setting portion A and the second electrode plate setting portion B on both sides are respectively connected to the second elastic torsion spring through a second connecting beam, and the out-of-plane displacement detection assembly also includes a second out-of-plane detection electrode plate A and a second out-of-plane detection electrode plate B arranged on the second electrode plate setting portion A and the second electrode plate setting portion B.

[0012] Preferably, in each pair of relatively arranged seesaw structures, one of the first pole plate setting parts B is arranged between the second pole plate setting part B and the second elastic torsion spring, and the second pole plate setting part B is arranged between one of the first pole plate setting parts B and the first elastic torsion spring, forming a structure in which the first pole plate setting part B of the first seesaw structure and the second pole plate setting part B of the second seesaw structure are nested with each other, and the first coupling structure is arranged between the first pole plate setting part B and the second pole plate setting part B that are nested with each other.

[0013] Preferably, the first connecting beam is provided with a first bending portion to avoid the second electrode plate setting portion B, and the second connecting beam is provided with a second bending portion to avoid the first electrode plate setting portion B.

[0014] Preferably, the out-of-plane displacement detection component is a Z-axis displacement detection component, and an X-axis acceleration detection component and / or a Y-axis acceleration detection component are arranged between the first electrode setting part A, the second electrode setting part A and the first elastic torsion spring, the second elastic torsion spring respectively.

[0015] Preferably, the out-of-plane displacement detection component is a Z-axis displacement detection component, and the first accommodating space A, the first accommodating space B, the second accommodating space A, and the second accommodating space B are respectively provided with an X-axis acceleration detection component and / or a Y-axis acceleration detection component.

[0016] Preferably, the micro-electromechanical system accelerometer includes two pairs of oppositely arranged seesaw structures, and the two pairs of oppositely arranged seesaw structures share a first coupling structure.

[0017] Preferably, the second coupling structure is an elastic coupling structure having at least one bending portion.

[0018] Preferably, the proof mass includes a first proof mass and a second proof mass, and the first coupling structure and the second coupling structure are connected to the first proof mass and the second proof mass, respectively.

[0019] (Inside plus outside)

[0020] Preferably, each pair of oppositely arranged seesaw structures includes a first seesaw structure and a second seesaw structure, the first seesaw structure including: a first anchor point, a first elastic torsion spring fixed to the first anchor point, and first connecting beams arranged on both sides of the first elastic torsion spring, wherein a first end of the first connecting beam is connected to the first elastic torsion spring, and a second end of the first connecting beam is connected to one of the second coupling structures; the second seesaw structure includes: a second anchor point, a second elastic torsion spring fixed to the second anchor point, and second connecting beams arranged on both sides of the second elastic torsion spring, wherein a first end of the second connecting beam is connected to the second elastic torsion spring, and a second end of the second connecting beam is connected to another of the second coupling structures, a first accommodation space A is formed between the first elastic torsion spring, the second coupling structure located on one side of the first seesaw structure, and the first connecting beam, and a first accommodation space B is formed between the first elastic torsion spring, the first coupling structure, and the first connecting beam;

[0021] A second accommodation space A is formed between the second elastic torsion spring, the second coupling structure located on one side of the second seesaw structure, and the second connecting beam, and a second accommodation space B is formed between the second elastic torsion spring, the first coupling structure, and the second connecting beam.

[0022] The first accommodating space A is provided with a first electrode plate setting portion A formed by extending the second proof mass, the first accommodating space B is provided with a first electrode plate setting portion B formed by extending the first proof mass, and the out-of-plane displacement detection assembly includes a first out-of-plane detection electrode plate A and a first out-of-plane detection electrode plate B provided on the first electrode plate setting portion A and the first electrode plate setting portion B;

[0023] The second accommodating space A is provided with a second electrode setting part A formed by extending the second inspection mass, and the second accommodating space B is provided with a second electrode setting part B formed by extending the first inspection mass. The out-of-plane displacement detection component includes a second out-of-plane detection electrode plate A and a second out-of-plane detection electrode plate B arranged on the second electrode setting part A and the second electrode setting part B.

[0024] Preferably, the micro-electromechanical system accelerometer includes two pairs of oppositely arranged seesaw structures, and the two pairs of oppositely arranged seesaw structures share a first coupling structure.

[0025] Compared with the related art, in the micro-electromechanical system accelerometer of the present invention, two or more seesaw structures are used as the structure of the proof mass support, so that the proof mass moves linearly along the Z axis under the action of the acceleration in the out-of-plane direction (Z direction). This linear displacement is not only conducive to improving the linearity of capacitive displacement detection, but also conducive to other non-capacitive detection methods, such as optical displacement detection. In addition, in the embodiment of the present invention, a dual coupling structure (first coupling structure, second coupling structure) is adopted to make the rotation of the seesaw co-coupled, thereby suppressing the other translational and rotational modes of the seesaw structure. Furthermore, in the embodiment of the present invention, the proof mass is mainly distributed on the second coupling structure (outside) (it can also be the first coupling structure on the inside), and a small amount of rotating proof mass is arranged on the seesaw structure or no rotating proof mass is arranged, so that the center of mass of the seesaw structure is close to or at the rotating axis. This distribution method of the proof mass makes the mass more concentrated, the structure more reasonable, and the parasitic modes less.

Brief Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0027] Figure 1 Schematic diagram of the structure of an existing out-of-plane acceleration sensor;

[0028] Figure 2 for Figure 1 Schematic diagram of the sensor's motion state;

[0029] Figure 3 This is a schematic diagram of the structure of an accelerometer according to the first embodiment of the present invention;

[0030] Figure 4 2 is a schematic structural diagram of the accelerometer according to the first embodiment of the present invention from another perspective;

[0031] Figure 5 This is a schematic diagram of the structure of an accelerometer according to the second embodiment of the present invention;

[0032] Figure 6 This is a schematic structural diagram of the accelerometer according to the second embodiment of the present invention from another perspective;

[0033] Figure 7 This is a schematic diagram of the structure of an accelerometer according to the third embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the structure of an accelerometer according to the fourth embodiment of the present invention;

[0035] Figure 9 This is a schematic diagram of the structure of an accelerometer according to a fifth embodiment of the present invention;

[0036] Figure 10 This is a schematic diagram of the structure of an accelerometer according to the sixth embodiment of the present invention;

[0037] Figure 11 This is a schematic diagram of the structure of an accelerometer according to the seventh embodiment of the present invention;

[0038] Figure 12 This is a schematic diagram of the structure of an accelerometer according to the eighth embodiment of the present invention;

[0039] Figure 13 This is a schematic diagram of the structure of an accelerometer according to the ninth embodiment of the present invention. [Specific implementation method]

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] Example 1

[0042] Please also see Figure 3-4 This embodiment provides a micro-electromechanical system accelerometer 200, comprising: a proof mass 230, at least one pair of oppositely arranged seesaw structures (210, 220), a substrate (not shown in the figure), and an out-of-plane displacement detection component 240, wherein the out-of-plane displacement detection component 240 is used to detect the rotation of the seesaw structures (210, 220) or the out-of-plane linear motion of the proof mass 230.

[0043] Among them, each two relatively arranged seesaw structures (210, 220) are coupled and connected on the first side through a first coupling structure 250 to form a symmetrical arrangement, and the second side of the two seesaw structures (210, 220) coupled and connected through the first coupling structure 250 is provided with a second coupling structure 260. In this embodiment, the second coupling structure 260 is connected to the inspection mass 230, and the first coupling structure 250 and the second coupling structure 260 are both elastic coupling structures.

[0044] Of course, in other optional embodiments, the coupling connection between each two oppositely arranged seesaw structures (210, 220) on the first side through the first coupling structure 250 can also be asymmetrical. The specific selection can be made according to actual conditions and will not be described one by one here.

[0045] In this embodiment, each pair of relatively arranged seesaw structures (210, 220) includes a first seesaw structure 210 and a second seesaw structure 220, and the first seesaw structure 210 includes: a first anchor point 211 fixed to the base at one end, a first elastic torsion spring 212 fixed to the other end of the first anchor point 211, and a first electrode plate setting portion A213a and a first electrode plate setting portion B213b relatively arranged on both sides of the first elastic torsion spring 212, the first electrode plate setting portion A213a and the first electrode plate setting portion B213b on both sides are respectively connected to the first elastic torsion spring 212 through a first connecting beam 214, the first end of the first connecting beam 214 close to the first coupling structure 250 is connected to the first elastic torsion spring 212, and the second end is connected to one of the first coupling structures 250, and the out-of-plane displacement detection component 240 includes a first out-of-plane detection electrode plate A241a and a first out-of-plane detection electrode plate B241b arranged on the first electrode plate setting portion A and the first electrode plate setting portion B213. The second seesaw structure 220 includes: a second anchor point 221 fixed to the base at one end, a second elastic torsion spring 222 fixed on the other end of the second anchor point 221, and a second pole plate setting portion A223a and a second pole plate setting portion B223b relatively arranged on both sides of the second elastic torsion spring 222, the second pole plate setting portion A223a and the second pole plate setting portion B223b on both sides are respectively connected to the second elastic torsion spring 222 through a second connecting beam 224, and the out-of-plane displacement detection component 240 also includes a second out-of-plane detection pole plate A242a and a second out-of-plane detection pole plate B242b arranged on the second pole plate setting portion A223a and the second pole plate setting portion B223b.

[0046] Example 2

[0047] like Figure 5 and Figure 6As shown, different from the first embodiment, one of the first electrode plate setting portions B213b is arranged between a second electrode plate setting portion B223b and the second elastic torsion spring 222, and a second electrode plate setting portion B223b is arranged between a first electrode plate setting portion B213b and the first elastic torsion spring 212, forming a structure in which a first electrode plate setting portion B213b of the first seesaw structure 210 and a second electrode plate setting portion B223b of the second seesaw structure 220 are nested with each other, and the first coupling structure 250 is arranged between the nested first electrode plate setting portion B213b and the second electrode plate setting portion B223b.

[0048] Furthermore, due to the symmetry of the seesaw structure, the first connecting beam 214 of the first seesaw structure 210 is provided with a first bending portion 215 to form a second electrode setting portion B223b that avoids the second seesaw structure 220. Similarly, the second connecting beam 224 of the second seesaw structure 220 is also provided with a second bending portion 225 to avoid the first electrode setting portion B213b.

[0049] In this embodiment, compared with the first embodiment, the out-of-plane capacitance detection plate is farther away from the rotation axis, so a greater gain can be obtained.

[0050] Example 3

[0051] Different from the second embodiment, in this embodiment, Figure 7 As shown, and reference Figure 5 The out-of-plane displacement detection assembly formed by the first out-of-plane detection plate A241a, the first out-of-plane detection plate B241, the second out-of-plane detection plate A242a, and the second out-of-plane detection plate B242b is a Z-axis displacement detection assembly. At the same time, an X-axis acceleration detection assembly 270 is provided between the other first plate setting portion A213a of the first seesaw structure 210 and the first elastic torsion spring 212 to detect acceleration in the X-axis direction. A Y-axis acceleration detection assembly 280 is provided between the other second plate setting portion A223a of the second seesaw structure 220 and the second elastic torsion spring 222 to detect acceleration in the Y-axis direction. Of course, the positions of the X-axis acceleration detection assembly 270 and the Y-axis acceleration detection assembly 280 can be interchanged, and the X-axis acceleration detection assembly 270 and the Y-axis acceleration detection assembly 280 can be provided selectively or simultaneously, depending on specific needs.

[0052] Example 4

[0053] like Figure 8As shown, in this embodiment, each pair of relatively arranged seesaw structures includes a first seesaw structure 210 and a second seesaw structure 220, and the first seesaw structure includes: a first anchor point 211, a first elastic torsion spring 212 fixed on the first anchor point 211, and first connecting beams 214 relatively arranged on both sides of the first elastic torsion spring 212, wherein the first end of the first connecting beam 214 close to the first coupling structure 250 is connected to the first elastic torsion spring 212, and the second end is connected to one of the first coupling structures 250, and the first end of the first connecting beam 214 away from the first coupling structure 250 is connected to the first elastic torsion spring 212, and the second end is connected to one of the second coupling structures 260.

[0054] The second seesaw structure 220 includes: a second anchor point 221, a second elastic torsion spring 222 fixed on the second anchor point 221, and second connecting beams 224 arranged on both sides of the second elastic torsion spring 222. The first end of the second connecting beam 224 on the side away from the first coupling structure 250 is connected to the second elastic torsion spring 222, and the second end is connected to another second coupling structure 260.

[0055] Different from the above-mentioned embodiment, this embodiment does not set a displacement detection component on the seesaw structure. Based on the seesaw structure of this embodiment, the out-of-plane displacement detection of the inspection mass can be achieved by arranging a capacitive detection plate on the inspection mass (upper surface or lower surface), and the out-of-plane displacement of the inspection mass can also be detected by setting an optical interference measurement component.

[0056] Example 5

[0057] Based on the above fourth embodiment and with reference to the attached Figure 8 A first accommodating space A215 is formed between the first elastic torsion spring 211, the second coupling structure 260 located on one side of the first seesaw structure 210, and the first connecting beam 214, and a first accommodating space B216 is formed between the first elastic torsion spring 211, the first coupling structure 250, and the first connecting beam 214.

[0058] A second accommodating space A225 is formed between the second elastic torsion spring 222, the second coupling structure 260 located on one side of the second seesaw structure 220, and the second connecting beam 224, and a second accommodating space B226 is formed between the second elastic torsion spring 222, the first coupling structure 250, and the second connecting beam 224.

[0059] like Figure 9 Shown and combined Figure 8Different from the fourth embodiment, in this embodiment, the proof mass includes a second proof mass 232 connected to the second coupling structure 260 and a first proof mass 231 connected to the first coupling structure 250 .

[0060] The first accommodating space A215 is provided with a first electrode setting portion A213a formed by extending the second inspection mass 232, and the first accommodating space B216 is provided with a first electrode setting portion B213b formed by extending the first inspection mass 231. The out-of-plane displacement detection component includes a first out-of-plane detection electrode A241a and a first out-of-plane detection electrode B241b arranged on the first electrode setting portion A213a and the first electrode setting portion B213b.

[0061] The second accommodating space A is provided with a second electrode setting portion A formed by extending the second inspection mass, and the second accommodating space B is provided with a second electrode setting portion B formed by extending the first inspection mass. The out-of-plane displacement detection component includes a second out-of-plane detection electrode plate A and a second out-of-plane detection electrode plate B provided on the second electrode setting portion A and the second electrode setting portion B.

[0062] In this embodiment, proof masses (first proof mass 231 and second proof mass 232) are provided in both first and second coupling structures 250 and 260. Capacitive detection plates are also provided on first and second proof masses 231 and 232. Second proof mass 232 forms a differential capacitor with the capacitive detection plates on first proof mass 231, while the masses cancel each other out. This structure has the advantage of converting all out-of-plane capacitance detection plate displacements into linear displacements, improving the linearity of acceleration detection. Furthermore, the out-of-plane capacitance detection plates are located at the top of the seesaw, ensuring the gain from acceleration to capacitance change.

[0063] Example 6

[0064] like Figure 10 As shown, this embodiment is based on the fourth embodiment and is a specific embodiment of a setting method for the out-of-plane displacement detection component. Figure 8 and combined Figure 10 ,

[0065] A first accommodating space A215 is formed between the first elastic torsion spring 211, the second coupling structure 260 located on one side of the first seesaw structure 210, and the first connecting beam 214, and a first accommodating space B216 is formed between the first elastic torsion spring 211, the first coupling structure 250, and the first connecting beam 214.

[0066] A second accommodating space A225 is formed between the second elastic torsion spring 222, the second coupling structure 260 located on one side of the second seesaw structure 220, and the second connecting beam 224, and a second accommodating space B226 is formed between the second elastic torsion spring 222, the first coupling structure 250, and the second connecting beam 224.

[0067] The out-of-plane displacement detection assembly is a Z-axis displacement detection assembly, which can be an out-of-plane capacitive detection plate installed on the proof mass, or other optical detection assembly. The first accommodation space A215, the first accommodation space B216, the second accommodation space A225, and the second accommodation space B226 are respectively equipped with an X-axis acceleration detection assembly 217 and / or a Y-axis acceleration detection assembly 218.

[0068] As an alternative embodiment, a groove may be formed on the proof mass 230 to place the X-axis acceleration detection assembly 270 and / or the Y-axis acceleration detection assembly 280 .

[0069] Example 7

[0070] The difference from the above embodiments is that the above embodiments all have a pair of seesaw structures, while this embodiment uses two pairs of seesaw structures. Figure 11 As shown, the MEMS accelerometer includes two pairs of seesaw structures arranged opposite to each other, namely a first seesaw structure 210a, a second seesaw structure 220a, a first seesaw structure 210b, and a second seesaw structure 220b. The two pairs of seesaw structures arranged opposite to each other share a first coupling structure 250.

[0071] In this embodiment, the first coupling structure 250 includes four symmetrically arranged connection points, and the two pairs of oppositely arranged seesaw structures (210, 220) are respectively connected to the four connection points to form a cross-arranged symmetrical structure.

[0072] On a plane, each seesaw structure is arranged in a square shape. Two pairs of seesaw structures, totaling four seesaw structures, are arranged crosswise on the plane to form a square occupied area. Test mass 230 is arranged around the periphery of the four seesaw structures. Of course, the shape of each seesaw structure is not limited to that provided in this embodiment.

[0073] In this embodiment, the second coupling structure 260 is an elastic coupling structure having at least one bending portion 261. Figure 11 As shown in FIG, in this embodiment, a bent portion 261 is used to make the second coupling structure 260 into a U-shaped structure. This allows the proof mass 230 to more easily drive the seesaw structure to rotate.

[0074] In this embodiment, the arrangement of four seesaw structures makes the structure more reasonable and better suppresses the motion of the non-sensitive axis mode. At the same time, more out-of-plane capacitance detection plates can be provided to provide a greater gain.

[0075] Example 8

[0076] like Figure 12 As shown, this embodiment adopts a multiple-pair seesaw structure setting similar to that of Example 7, except that a mutually nested structure similar to that of Example 2 is adopted, that is, a mutually nested setting structure is formed between one of the first electrode setting parts B231b of a pair of seesaw structures and a second electrode setting part B232b of the other pair of seesaw structures.

[0077] In this embodiment, a nested arrangement is adopted so that the out-of-plane capacitance detection plate is away from the rotation axis, thereby obtaining a greater gain and making the structure more compact.

[0078] Embodiment 9

[0079] like Figure 13 As shown, different from the eighth embodiment, the seesaw structure does not have an out-of-plane capacitance detection plate. Instead, the out-of-plane capacitance detection plate is provided on the second inspection mass 232 and the first inspection mass 231 . The first inspection mass 231 and the first coupling structure 250 are an integrated structure.

[0080] Based on the above embodiments, it can be seen that in various embodiments of the present invention, the proof mass can be the second proof mass 232 disposed only on the second coupling structure 260 , or the first proof mass 231 disposed only on the first coupling structure 250 .

[0081] Based on the above embodiments, it can be seen that in various embodiments of the present invention, the second proof mass 232 can be symmetrically arranged around the seesaw structure, or can be independently arranged similar to the first proof mass 231.

[0082] Based on the above embodiments, it can be seen that in the embodiments of the present invention, the number of seesaw structures can be an even number, and a symmetrical arrangement can be achieved through the first coupling structure.

[0083] Based on the above embodiments, it can be seen that in the embodiments of the present invention, the out-of-plane displacement detection component can be an out-of-plane capacitance detection plate, or can be other optical detection components, or other types of displacement detection components.

[0084] Based on the above embodiments, it can be seen that in the embodiments of the present invention, the out-of-plane displacement detection component can be arranged on the proof mass, or on the seesaw structure, or on the first coupling structure.

[0085] Compared with the related art, in the MEMS accelerometer of each embodiment of the present invention, two or more seesaw structures are used as the structure for supporting the test mass, so that the test mass moves linearly along the Z axis under the action of acceleration in the out-of-plane direction (Z direction). This linear displacement is not only beneficial to improving the linearity of capacitive displacement detection, but also beneficial to other non-capacitive detection methods, such as optical displacement detection. In addition, in the embodiment of the present invention, a dual coupling structure (first coupling structure, second coupling structure) is adopted to make the rotation of the seesaw co-coupled, thereby suppressing the other translational and rotational modes of the seesaw structure. Furthermore, in the embodiment of the present invention, the test mass is mainly distributed on the second coupling structure (outside) (it can also be the first coupling structure on the inside), and a small amount of rotating test mass is arranged on the seesaw structure or no rotating test mass is arranged, so that the center of mass of the seesaw structure is close to or at the rotation axis. This distribution method of the test mass makes the mass more concentrated, the structure more reasonable, and the parasitic modes less.

[0086] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. A micro-electromechanical system accelerometer, characterized in that: include: a proof mass, at least one pair of opposing seesaw structures, a substrate, and an out-of-plane displacement detection assembly, wherein the seesaw structures are fixedly connected to the substrate via anchor points, and the out-of-plane displacement detection assembly is configured to detect rotation of the seesaw structures or out-of-plane linear motion of the proof mass; Wherein, each two of the seesaw structures arranged opposite to each other are coupled on a first side via a first coupling structure, a second coupling structure is provided on a second side of the two seesaw structures coupled via the first coupling structure, the first coupling structure and / or the second coupling structure are connected to the proof mass, and both the first coupling structure and the second coupling structure are elastic coupling structures; Each pair of oppositely arranged seesaw structures includes a first seesaw structure and a second seesaw structure, wherein the first seesaw structure includes: a first anchor point fixed to the base, a first elastic torsion spring fixed on the first anchor point, and first connecting beams arranged on both sides of the first elastic torsion spring, wherein the first end of the first connecting beam on the side away from the first coupling structure is connected to the first elastic torsion spring, and the second end is connected to one of the second coupling structures; the second seesaw structure includes: one end fixed to the second anchor point of the base, a second elastic torsion spring fixed on the other end of the second anchor point, and second connecting beams arranged on both sides of the second elastic torsion spring, wherein the first end of the second connecting beam on the side away from the first coupling structure is connected to the second elastic torsion spring, and the second end is connected to another of the second coupling structures.

2. The micro-electromechanical system accelerometer according to claim 1, characterized in that: Only the first coupling structure or only the second coupling structure is connected to the proof mass.

3. The micro-electromechanical system accelerometer according to claim 1, characterized in that: The micro-electromechanical system accelerometer includes two pairs of seesaw structures arranged opposite to each other, and the two pairs of seesaw structures arranged opposite to each other share a first coupling structure.

4. The micro-electromechanical system accelerometer according to claim 3, characterized in that: The second coupling structure is an elastic coupling structure having at least one bending portion.

5. The MEMS accelerometer according to claim 1, wherein: The proof mass includes a first proof mass and a second proof mass, and the first coupling structure and the second coupling structure are connected to the first proof mass and the second proof mass, respectively.

6. The micro-electromechanical system accelerometer according to claim 5, characterized in that: A first accommodation space A is formed between the first elastic torsion spring, the second coupling structure located on one side of the first seesaw structure, and the first connecting beam, and a first accommodation space B is formed between the first elastic torsion spring, the first coupling structure, and the first connecting beam; A second accommodation space A is formed between the second elastic torsion spring, the second coupling structure located on one side of the second seesaw structure, and the second connecting beam, and a second accommodation space B is formed between the second elastic torsion spring, the first coupling structure, and the second connecting beam. The first accommodating space A is provided with a first electrode plate setting portion A formed by extending the second proof mass, the first accommodating space B is provided with a first electrode plate setting portion B formed by extending the first proof mass, and the out-of-plane displacement detection assembly includes a first out-of-plane detection electrode plate A and a first out-of-plane detection electrode plate B provided on the first electrode plate setting portion A and the first electrode plate setting portion B; The second accommodating space A is provided with a second electrode setting part A formed by extending the second inspection mass, and the second accommodating space B is provided with a second electrode setting part B formed by extending the first inspection mass. The out-of-plane displacement detection component includes a second out-of-plane detection electrode plate A and a second out-of-plane detection electrode plate B arranged on the second electrode setting part A and the second electrode setting part B.

7. The micro-electromechanical system accelerometer according to claim 6, characterized in that: The out-of-plane displacement detection component is a Z-axis displacement detection component, and the first accommodating space A, the first accommodating space B, the second accommodating space A, and the second accommodating space B are respectively provided with an X-axis acceleration detection component and / or a Y-axis acceleration detection component.

8. The MEMS accelerometer according to claim 5, wherein: The micro-electromechanical system accelerometer includes two pairs of seesaw structures arranged opposite to each other, and the two pairs of seesaw structures arranged opposite to each other share a first coupling structure.

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