MEMS element and electro-acoustic conversion device

Abstract

The invention provides an MEMS element and an electro-acoustic conversion device, and relates to the technical field of microphones. The MEMS element includes a spacer, a counter electrode, a first diaphragm, and a second diaphragm. The spacers and the counter electrodes are located on the same horizontal plane and are alternately arranged on the cross section of the MEMS element. The first diaphragm and the second diaphragm are disposed on opposite sides of the spacer, respectively, and are hermetically connected. The first membrane comprises a plurality of first protrusions arranged at intervals in the first direction, and the second membrane comprises a plurality of second protrusions arranged at intervals in the first direction. The first protrusions and the second protrusions are in one-to-one correspondence and are aligned with each other to form a cavity, and the counter electrode is arranged in the cavity in a suspended mode. The first protrusion comprises a first front wall and a first rear wall, the second protrusion comprises a second front wall and a second rear wall, and at least part of the first front wall, the first rear wall, the second front wall or the second rear wall is of a sub-corrugated structure. The MEMS element can reduce the maximum stress applied to the diaphragm under high-pressure impact, so that the mechanical firmness of the device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electroacoustic conversion devices, and in particular to a MEMS element and an electroacoustic conversion device. Background Art

[0002] In the field of Micro-Electro-Mechanical System (MEMS) microphones, some structures may be designed with a sealed cavity surrounded by two corrugated diaphragms, where the sealed cavity presents a reduced air pressure and is provided with a back plate that acts as a counter electrode to form a capacitive differential sensing system.

[0003] When the dual diaphragm structure is subjected to high pressure (from falling or air impact - about 1 MPa), the diaphragm will be subjected to high upward or downward displacement (about tens of microns) accordingly. Under such high displacement, high stress will appear locally in the diaphragm and cracks may be generated in the material, which will damage the structure and eventually damage the microphone.

[0004] It would therefore be desirable to provide an improved MEMS component that overcomes at least one of the above-mentioned problems. Summary of the invention

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a MEMS element, including:

[0006] a plurality of spacers arranged along a first direction,

[0007] A plurality of pairs of electrodes arranged along a first direction,

[0008] a plurality of slots, each of which is formed between adjacent counter electrodes and spacers;

[0009] A first diaphragm, comprising a plurality of first protrusions spaced apart along a first direction;

[0010] A second diaphragm includes a plurality of second protrusions spaced apart along the first direction, the second protrusions extending in a direction away from the first protrusions;

[0011] The plurality of spacers and the plurality of counter electrodes are located in the same horizontal plane and are alternately arranged in a cross section of the MEMS element;

[0012] The first diaphragm and the second diaphragm are respectively disposed on opposite sides of the spacer and are airtightly connected;

[0013] The plurality of first protrusions correspond to the plurality of second protrusions one by one, and the corresponding first protrusions and second protrusions are aligned with each other to form a cavity, and the counter electrode is suspended in the cavity;

[0014] The portion between two adjacent first protrusions is the first portion, the portion between two adjacent second protrusions is the second portion, the corresponding first portions and second portions are aligned, and the spacer is sandwiched between the first portion and the second portion;

[0015] The first protrusion includes a first front wall and a first rear wall which are arranged opposite to each other along a first direction, and the second protrusion includes a second front wall and a second rear wall which are arranged opposite to each other along the first direction;

[0016] At least a portion of the first front wall, the first rear wall, the second front wall, and the second rear wall is a sub-corrugated structure.

[0017] In some embodiments, the first front wall and the first rear wall adjacent to the first portion of the spacer connected to the edge of the first diaphragm are sub-corrugated structures, and the second front wall and the second rear wall adjacent to the second portion of the spacer connected to the edge of the second diaphragm are sub-corrugated structures.

[0018] In some embodiments, the first front wall and the first rear wall adjacent to the first portion of the spacer connected to the outermost circle or the sub-outer circle of the first diaphragm are sub-corrugated structures, and the second front wall and the second rear wall adjacent to the second portion of the spacer connected to the outermost circle or the sub-outer circle of the second diaphragm are sub-corrugated structures.

[0019] In some embodiments, the first front wall and the first rear wall adjacent to the first portion of the spacer connected to the outermost two or three turns of the first diaphragm are sub-corrugated structures, and the second front wall and the second rear wall adjacent to the second portion of the spacer connected to the outermost two or three turns of the second diaphragm are sub-corrugated structures.

[0020] In some embodiments, the first front wall and the first rear wall adjacent to the first portion of all spacers connected to the first diaphragm are sub-corrugated structures, and the second front wall and the second rear wall adjacent to the second portion of all spacers connected to the second diaphragm are sub-corrugated structures.

[0021] In some embodiments, the sub-corrugated structure includes a third peak and a third valley connected to each other along the first direction, the third peak is connected to the first portion and the second portion respectively, and the third valley is connected to the top of the first protrusion and the second protrusion respectively.

[0022] In some embodiments, the top of the third peak and the bottom of the third valley are conical or flat.

[0023] In some embodiments, the top of the third peak is lower than or flush with the tops of the first protrusion and the second protrusion.

[0024] In some embodiments, the bottom of the third valley is higher than or flush with the height of the first portion and the second portion.

[0025] In some embodiments, the length of the sub-corrugated structure in the first direction is smaller than the length of the first protrusion, the second protrusion, the first portion, or the second portion.

[0026] In some embodiments, the sub-corrugated structure is integrally formed with the first diaphragm or the second diaphragm.

[0027] In some embodiments, the shape and size of the first protrusion are the same as the shape and size of the second protrusion, and the length of the first portion is the same as the length of the second portion.

[0028] In some embodiments, the tops of the first protrusion and the second protrusion are flat, and the first portion and the second portion are flat.

[0029] In some embodiments, the cavity is sealed and the internal pressure is less than the external atmospheric pressure.

[0030] In some embodiments, the cavity is in a vacuum state.

[0031] In some embodiments, the first direction is radial or lateral.

[0032] In some embodiments, the first diaphragm and the second diaphragm are made of a conductive material, or include a layer of insulating film with a conductive element disposed on the film.

[0033] In some embodiments, the first diaphragm and the second diaphragm further each include a plurality of spokes, dividing the first diaphragm and the second diaphragm into a plurality of parts along a circumferential direction.

[0034] In some embodiments, at least a portion of the counter electrode is suspended between the sub-corrugated structure of the first diaphragm and the corresponding sub-corrugated structure of the second diaphragm, and two opposite surfaces of the counter electrode are not in contact with the sub-corrugated structures of the first diaphragm and the second diaphragm respectively.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] By setting at least a portion of the first front wall, the first rear wall, the second front wall or the second rear wall to be a sub-corrugated structure, since the sub-corrugated structure has an additional degree of bending freedom, it is allowed to have a different deformation from the double diaphragm structure and release stress through the deformation. Therefore, it can share the stress at the corner where the first protrusion or the second protrusion is connected to the respective diaphragms, thereby ultimately reducing the maximum stress of the diaphragm; at the same time, the MEMS element can also maintain the original stiffness of the first diaphragm and the second diaphragm, so that the original performance can be maintained, thereby greatly improving the robustness of the equipment, effectively reducing the maximum stress applied to the diaphragm under high-pressure shock (drop, air shock), and ultimately improving the mechanical robustness of the device.

[0037] In addition, the MEMS component of the present invention has higher acoustic compliance and sensitivity.

[0038] In order to solve the above technical problems, the present invention further provides an electroacoustic conversion device, comprising the MEMS element as described above, and a circuit electrically connected to the MEMS element.

[0039] The advantages of the electroacoustic converter over the prior art are the same as those of the above-mentioned MEMS element, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0041] Figure 1 A schematic top view of a MEMS element including radial corrugations in some embodiments of the present invention;

[0042] Figure 2 For the embodiment of the present invention Figure 1 A partial cross-sectional view of a MEMS element;

[0043] Figure 3 A partial cross-sectional view of a MEMS element having sub-corrugations in some embodiments of the present invention;

[0044] Figure 4 Partial cross-sectional views of MEMS elements with sub-corrugations in other embodiments of the present invention.

[0045] The following are the explanations of the reference numerals: The reference numerals should not be construed as limiting the claims.

[0046] 11. spacer; 12. counter electrode; 13. slot; 2. first diaphragm; 21. first protrusion; 22. first portion; 211. first front wall; 212. first rear wall; 4. spoke; 3. second diaphragm; 31. second protrusion; 32. second portion; 311. second front wall; 312. second rear wall; 41. cavity; 5. corrugated structure; 51. third peak; 52. third valley. DETAILED DESCRIPTION

[0047] The present invention will be further described with reference to the accompanying drawings. It should be noted that elements of similar structure or function are represented by the same reference numerals throughout the figures. The embodiments described herein are not intended to be an exhaustive description or description of various other embodiments, nor are they intended to be a limitation on the scope of the claims or the scope of certain other embodiments that would be apparent to a person of ordinary skill in the art based on the embodiments described herein. In addition, the illustrated embodiments do not necessarily have all the aspects or advantages shown. In the description of the present invention, it should be understood that the terms "first", "second", "third", etc. are primarily used to distinguish between different devices, elements, or components (specific types and configurations may be the same or different), and are not intended to indicate or imply the relative importance and quantity of the indicated devices, elements, or components. Unless otherwise specified, the meaning of "multiple" is two or more.

[0048] The terms used in the various embodiments described herein are only used to describe specific embodiments and are not restrictive. As used in the description of the various embodiments described and the appended claims, the singular forms "one", "an" and "said" are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any and all possible combinations of one or more related listed items. It should be further understood that the terms "include", "comprise", "have", "have" when used in this specification, specify the presence of the features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0049] Reference Figures 1 to 4 , an embodiment of the present invention provides a MEMS element. The MEMS element includes a plurality of spacers 11, a plurality of counter electrodes 12, a first diaphragm 2 and a second diaphragm 3. The plurality of spacers 11 and the plurality of counter electrodes 12 are arranged along a first direction, are located in the same horizontal plane, and are alternately arranged on the cross section of the MEMS element. A gap is left between adjacent counter electrodes 12 and spacers 11 to form a narrow groove 13. The first diaphragm 2 and the second diaphragm 3 have similar corrugated structures, each including a plurality of protrusions arranged at intervals along the first direction, and each protrusion extends in opposite directions in the second direction. In addition, the first diaphragm 2 is arranged opposite to the second diaphragm 3 and is airtightly connected. In which, the first direction is expressed as radial or transverse, and the second direction is expressed as vertical.

[0050] For the convenience of description, the protrusion of the first diaphragm 2 may be referred to as the first protrusion 21, and the protrusion of the second diaphragm 3 may be referred to as the second protrusion 31. The first protrusion 21 and the second protrusion 31 may have the same shape and size. On the surface perpendicular to the first diaphragm 2 and the second diaphragm 3 (i.e., the surface in the second direction), the shape of the first protrusion 21 and the second protrusion 31 may be a rectangle, a trapezoid, a triangle, etc.

[0051] The portion between two adjacent first protrusions 21 on the first diaphragm 2 is called the first portion 22 (i.e., the portion on the first diaphragm 2 other than the first protrusions 21), and the portion between two adjacent second protrusions 31 on the second diaphragm 3 is called the second portion 32 (i.e., the portion on the second diaphragm 3 other than the second protrusions 31). The first portion 22 and the second portion 32 may have the same shape and size, for example, may be flat. Therefore, the first portion 22 and the second portion 32 may have the same length.

[0052] The first protrusion 21 and the second protrusion 31 are aligned with each other to form a cavity 41, and the counter electrode 12 is suspended in the cavity 41. The first portion 22 is aligned with the second portion 32, respectively, and connected by the spacer 11. In other words, one end of the spacer 11 is connected to the first portion 22, and the other end is connected to the second portion 32, that is, the spacer 11 is sandwiched between the first portion 22 and the second portion 32.

[0053] The spacer 11 may be a pillar, etc. The spacer 11 may be formed integrally with the first diaphragm 2 or the second diaphragm 3. Alternatively, after the first diaphragm 2 and the second diaphragm 3 are assembled together, the spacer 11 is formed between them.

[0054] It should be noted that the first diaphragm 2 and the second diaphragm 3 are both corrugated conductive diaphragms with the same shape and size, and can generally be circular. In some embodiments, the first diaphragm 2 and the second diaphragm 3 are divided into six parts in the circumferential direction, and the adjacent parts are connected to each other by spokes 4 extending along the radial direction of the diaphragm (i.e., the first direction). In other words, the first diaphragm and the second diaphragm may further include a plurality of spokes 4. In some other embodiments, the first diaphragm 2 and the second diaphragm 3 may also have other shapes, such as square, hexagonal, octagonal, etc., which are not limited here.

[0055] In some embodiments, the first corrugated conductive diaphragm 2 and the second corrugated conductive diaphragm 3 may be made of a conductive material or include an insulating film on which a conductive element is provided. For example, the first corrugated conductive diaphragm 2 and the second corrugated conductive diaphragm 3 include a silicon nitride film, wherein a polysilicon electrode is formed on the surface of the diaphragm facing the counter electrode 12 to provide conductivity.

[0056] like Figures 2 to 4As shown, the first corrugated conductive diaphragm 2 includes a plurality of first protrusions 21 and a plurality of first portions alternately arranged along a first direction, and the second corrugated conductive diaphragm 3 includes a plurality of second protrusions 31 and a plurality of second portions alternately arranged along the first direction. The second protrusions 31 extend in a direction away from the first protrusions 21, while the second portions 32 extend in a direction toward the first portions 21. Since the first protrusions 21 and the second protrusions 31 have the same shape and size, and the first portions 22 and the second portions 32 also have the same shape and size, the first corrugated conductive diaphragm 2 and the second corrugated conductive diaphragm 3 have the same length.

[0057] It should be noted that the tops of the first protrusion 21 and the second protrusion 32 are, for example, but not limited to, flat. Figures 2 to 4 In some other embodiments, the tops of the first protrusion 21 and the second protrusion 32 may also be V-shaped, arched or arc-shaped protrusions, which are not limited here.

[0058] The protrusions of the first diaphragm 2 and the second diaphragm 3 respectively include front walls and rear walls arranged opposite to each other along the first direction. For ease of description, the front wall and rear wall of the first protrusion 21 can be referred to as the first front wall 211 and the first rear wall 212, and the front wall and rear wall of the second protrusion 31 can be referred to as the second front wall 311 and the second rear wall 312.

[0059] The inclination angles of the first front wall 211 , the first rear wall 212 , the second front wall 311 , and the second rear wall 312 may be greater than 0° but less than or equal to 90°.

[0060] Since the corners where the diaphragm is connected to the front wall and the rear wall will have local high stress when the diaphragm is subjected to high pressure, it will cause damage to the structure. Therefore, in some embodiments, at least part of the front wall or the rear wall is set to a sub-corrugated structure 5. Specifically, as Figure 3 and Figure 4 As shown, at least a portion of the first front wall 211 , the first rear wall 212 , the second front wall 311 or the second rear wall 312 is a sub-corrugated structure 5 .

[0061] When the diaphragm is subjected to high pressure, the sub-corrugated structure 5 can effectively reduce the local stress through its own buffering, thereby effectively reducing the maximum stress applied to the diaphragm under high pressure shock (drop, air shock), and ultimately improving the mechanical robustness of the device.

[0062] When the MEMS element is subjected to high pressure (e.g., from falling or air impact, up to 1 MPa), the inclined surfaces of the protrusions corresponding to the outermost and second outermost spacers 11 are subjected to the greatest local stress impact. Therefore, preferably, the front wall and the rear wall adjacent to the first and second parts of the outermost or second outermost spacers 11 connected to the first and second diaphragms are provided with sub-corrugated structures 5. In this case, the MEMS element can effectively reduce the local stress while better maintaining the original characteristics.

[0063] In some embodiments, the front wall and the rear wall adjacent to the first and second parts of the outermost two or three circles of the spacer 11 connected to the first and second diaphragms can be set as a sub-corrugated structure. In some embodiments, the front wall and the rear wall adjacent to the first and second parts of all the spacers connected to the first and second diaphragms can be set as a sub-corrugated structure.

[0064] like Figure 3 and Figure 4 As shown, in order to maintain the consistency of the diaphragm extending in the radial direction or in the lateral direction, in some embodiments, the sub-corrugated structures 5 are also arranged along the first direction. However, in some other embodiments, the corrugated structures 5 can also be arranged in a manner that forms a certain angle (e.g., 0° to 30°) with the first direction, for example, along Figure 2 The original extension direction of the front wall or the rear wall is not limited here.

[0065] The sub-corrugated structure 5 includes a third peak 51 and a third valley 52 connected to each other along a first direction. The third peak 51 extends in a direction away from the first diaphragm and the second diaphragm, respectively, and the third valley 52 extends in a direction toward the first diaphragm and the second diaphragm, respectively. Specifically, the third peak 51 is connected to the first portion 22 and the second portion 32, and the third valley 52 is connected to the top of the first protrusion 21 and the second protrusion 31. The connection here means that the first portion 22 and the second portion 32 are each connected to a third peak 51, and the third valley 52 is respectively connected to the top of the first protrusion 21 and the second protrusion 31.

[0066] The height of the third peak 51 is less than or equal to the height of the first protrusion 21 and the second protrusion 31. In some embodiments, the height of the third peak 51 is the same as the height of the first protrusion 21 and the second protrusion 31. The height described here refers to the highest point.

[0067] The bottom of the third valley 52 is not lower than the height of the first portion 22 and the second portion 32. In some embodiments, the bottom of the third valley 52 is in the same plane as the first portion 22 and the second portion 32.

[0068] In some embodiments, the top of the third peak 51 and the bottom of the third valley 52 may be conical or flat.

[0069] In some embodiments, the length of the sub-corrugated structure 5 in the first direction is less than the length of the first protrusion 21, the second protrusion 31, the first portion 22, or the second portion 32. For example, including but not limited to, the length of the sub-corrugated structure 5 in the first direction may be 1 / 2, 1 / 3, 1 / 4, 2 / 3, 3 / 4, 2 / 5, 4 / 5, etc. of the length of the first protrusion 21, the second protrusion 31, the first portion 22, or the second portion 32.

[0070] In some embodiments, the sub-corrugated structure 5 may be integrally formed with the first diaphragm 2 and / or the second diaphragm 3 .

[0071] like Figure 4 As shown, a gap is usually left between the sub-corrugated structure 5 at the first front wall 211 of the first protrusion 21 and the sub-corrugated structure 5 at the second front wall 311 of the second protrusion 31, and the electrode 12 can also be suspended in the gap, that is, at least a part of the electrode 12 is arranged between the sub-corrugated structure 5 of the first diaphragm 2 and the sub-corrugated structure 5 of the second diaphragm 3 opposite thereto, and the two opposite surfaces of the electrode 12 are not in contact with the sub-corrugated structures 5 of the first diaphragm 2 and the second diaphragm 3.

[0072] Since the sub-corrugated structure 5 has an additional bending freedom, it is allowed to have a different deformation from the double diaphragm structure and release stress through the deformation. Therefore, the stress at the corner where the first protrusion 21 or the second protrusion 31 is connected to the respective diaphragm can be shared, thereby ultimately reducing the maximum stress of the diaphragm. At the same time, the MEMS element can also maintain its original stiffness and performance.

[0073] Another embodiment of the present invention provides an electroacoustic conversion device, including the above-mentioned MEMS element, and a circuit electrically connected to the MEMS element. The electroacoustic conversion device can be a MMEMS microphone or a speaker. Although the present invention is described with reference to one or more embodiments, the above description of the embodiments is only used to enable those skilled in the art to implement or use the present invention. Those skilled in the art should understand that various modifications can be made without departing from the spirit or scope of the present invention. The embodiments described above should not be interpreted as limitations on the present invention, and the scope of the present invention should be determined with reference to the appended claims.

Claims

1. A micro-electromechanical system (MEMS) element, characterized in that: include: a plurality of spacers arranged along a first direction, A plurality of pairs of electrodes arranged along the first direction, a plurality of slots, each slot being formed between adjacent counter electrodes and spacers; A first diaphragm, comprising a plurality of first protrusions spaced apart along the first direction; A second diaphragm, comprising a plurality of second protrusions spaced apart along the first direction, wherein the second protrusions extend in a direction away from the first hollow protrusion; The plurality of spacers and the plurality of counter electrodes are located in the same horizontal plane and are alternately arranged in a cross section of the MEMS element; The first diaphragm and the second diaphragm are respectively arranged on opposite sides of the spacer and are airtightly connected; The plurality of first protrusions correspond to the plurality of second protrusions one by one, and the corresponding first protrusions and second protrusions are aligned with each other to form a cavity, and the pair of electrodes are suspended in the cavity; The portion between two adjacent first protrusions is the first portion, the portion between two adjacent second protrusions is the second portion, the corresponding first portions and second portions are aligned, and the spacer is sandwiched between the first portion and the second portion; The first protrusion includes a first front wall and a first rear wall disposed opposite to each other along the first direction, and the second protrusion includes a second front wall and a second rear wall disposed opposite to each other along the first direction; At least a portion of the first front wall, the first rear wall, the second front wall or the second rear wall is a sub-corrugated structure.

2. The MEMS element according to claim 1, characterized in that: The first front wall and the first rear wall adjacent to the first portion of the spacer connected to the edge of the first diaphragm are sub-corrugated structures, and the second front wall and the second rear wall adjacent to the second portion of the spacer connected to the edge of the second diaphragm are sub-corrugated structures.

3. The MEMS element according to claim 1, characterized in that: The first front wall and the first rear wall adjacent to the first part of the spacer connected to the outermost circle or the sub-outer circle of the first diaphragm are sub-corrugated structures, and the second front wall and the second rear wall adjacent to the second part of the spacer connected to the outermost circle or the sub-outer circle of the second diaphragm are sub-corrugated structures.

4. The MEMS element according to claim 1, characterized in that: The first front wall and the first rear wall adjacent to the first part of the spacer connected to the outermost two or three turns of the first diaphragm are sub-corrugated structures, and the second front wall and the second rear wall adjacent to the second part of the spacer connected to the outermost two or three turns of the second diaphragm are sub-corrugated structures.

5. The MEMS element according to claim 1, characterized in that: The first front wall and the first rear wall adjacent to the first portion of all spacers connected to the first diaphragm are sub-corrugated structures, and the second front wall and the second rear wall adjacent to the second portion of all spacers connected to the second diaphragm are sub-corrugated structures.

6. The MEMS element according to any one of claims 1 to 5, characterized in that: The sub-corrugated structure includes a third peak and a third valley connected to each other along the first direction, the third peak is connected to the first portion and the second portion, and the third valley is connected to the top of the first protrusion and the second protrusion.

7. The MEMS element according to claim 6, characterized in that: The top of the third peak and the bottom of the third valley are conical or flat.

8. The MEMS element according to claim 7, characterized in that: The top of the third peak is lower than or flush with the tops of the first protrusion and the second protrusion.

9. The MEMS element according to claim 7, characterized in that: The bottom of the third valley is higher than or flush with the heights of the first portion and the second portion.

10. The MEMS element according to any one of claims 1 to 5, characterized in that: The length of the sub-corrugated structure in the first direction is smaller than the length of the first protrusion, the second protrusion, the first portion or the second portion.

11. The MEMS element according to any one of claims 1 to 5, characterized in that: The sub-corrugated structure is integrally formed with the first diaphragm or the second diaphragm.

12. The MEMS element according to any one of claims 1 to 5, characterized in that: The shape and size of the first protrusion are the same as those of the second protrusion, and the length of the first portion is the same as that of the second portion.

13. The MEMS element according to any one of claims 1 to 5, characterized in that: The tops of the first protrusion and the second protrusion are flat, and the first portion and the second portion are flat.

14. The MEMS element according to any one of claims 1 to 5, characterized in that: The cavity is sealed, and the pressure inside the cavity is lower than the external atmospheric pressure.

15. The MEMS element according to any one of claims 1 to 5, characterized in that: The cavity is in a vacuum state.

16. The MEMS element according to any one of claims 1 to 5, characterized in that: The first direction is radial or transverse.

17. The MEMS element according to any one of claims 1 to 5, characterized in that: The first diaphragm and the second diaphragm are made of conductive material, or include a layer of insulating film, on which conductive elements are arranged.

18. The MEMS element according to any one of claims 1 to 5, characterized in that: The first diaphragm and the second diaphragm further each include a plurality of spokes, and the spokes divide the first diaphragm and the second diaphragm into a plurality of parts along a circumferential direction.

19. The MEMS element according to any one of claims 1 to 5, characterized in that: At least a portion of the counter electrode is suspended between the sub-corrugated structure of the first diaphragm and the corresponding sub-corrugated structure of the second diaphragm, and two opposite surfaces of the counter electrode are not in contact with the sub-corrugated structures of the first diaphragm and the second diaphragm respectively.

20. An electroacoustic conversion device, characterized in that: The method comprises the MEMS element according to any one of claims 1 to 19, and a circuit electrically connected to the MEMS element.

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