Piezoelectric MEMS microphone

Patent metadata

Field	Value
Publication number	US-11212623-B2
Application number	US-202016988738-A
Country	US
Kind code	B2
Filing date	Aug 10, 2020
Priority date	Aug 16, 2019
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

The invention provides a piezoelectric micro-electromechanical systems (MEMS) microphone having a base with a cavity, a piezoelectric diaphragm, and a limit element. The base has a ring base, and a support column. The piezoelectric diaphragm includes diaphragm sheets. Each diaphragm sheet have a fixing end connected with the support column and a free end suspended above the cavity. The limit element includes a limit part arranged apart from the piezoelectric diaphragm to limit the free ends in vibration directions of the diaphragm sheets, and an edge fixing plate connected with the outer edge of the limit part and arranged on the ring base. When the diaphragm sheets greatly deform upwards under impact force, deformation of the diaphragm sheets can be controlled, and the diaphragm sheets are protected to prevent the diaphragm sheets from breaking, thereby improving the stability of the piezoelectric MEMS microphone.

First claim

What is claimed is:

1. A piezoelectric micro-electromechanical system (MEMS) microphone, comprising:
a base with a cavity, including a ring base, and a support column arranged apart from the ring base and located at an inner side of the ring base;
a piezoelectric diaphragm arranged on the base, including a plurality of diaphragm sheets each having a fixing end connected with the support column and a free end suspended above the cavity;
a limit element covering outside the piezoelectric diaphragm, comprising a limit part arranged apart from the piezoelectric diaphragm for limiting the free ends in a vibration direction of the diaphragm, and an edge fixing plate connected with the outer edge of the limit part and arranged on the ring base;
and a plurality of first through holes formed in the limit part for being arranged opposite to the cavity.

2. The piezoelectric MEMS microphone as described in claim 1 , wherein the base further comprises a plurality of support beams; one ends of the support beams are connected with the support column, and the other ends are connected with the ring base for dividing the cavity into a plurality of sub-cavities.

3. The piezoelectric MEMS microphone as described in claim 2 , wherein the piezoelectric diaphragm is of an integral structure; the piezoelectric diaphragm is provided with breathable seams extending from the outer edge thereof to the center of the piezoelectric diaphragm; and the breathable seams divide the piezoelectric diaphragm into diaphragm sheets.

4. The piezoelectric MEMS microphone as described in claim 2 , wherein the limit part comprises a limit plate extending towards the support column from one side of the edge fixing plate far away from the ring base; and the limit plate covers a part of free ends.

5. The piezoelectric MEMS microphone as described in claim 4 , wherein the limit part further comprises an intermediate fixing plate connected with the support column, and a plurality of support plates separately arranged directly opposite to the plurality of support beams in a manner of one-to-one correspondence; one end of each support plate is connected with the limit plate and the other end is connected with the intermediate fixing plate; each support plate covers a part of free ends; and the intermediate fixing plate, two adjacent support plates and the limit plate define one first through hole.

6. The piezoelectric MEMS microphone as described in claim 5 further including one blocking board arranged between the intermediate fixing plate and the limit plate above each diaphragm sheet, wherein one end of each blocking board is connected with the intermediate fixing plate and the other end is connected with the limit plate.

7. The piezoelectric MEMS microphone as described in claim 5 further including one blocking board is arranged between two adjacent support plates above each diaphragm sheet, one end of each blocking board is connected with one support plate and the other end is connected with another adjacent support plate.

8. The piezoelectric MEMS microphone as described in claim 5 , further comprising a gasket arranged between the base and the piezoelectric diaphragm, wherein the gasket comprises an edge fixing pad arranged in a surrounding manner along an extension direction of the ring base; the inner side of the edge fixing pad and the ring base form a base avoidance zone; a projection of the outer edge of the piezoelectric diaphragm on the base is positioned within the projection of the outer edge of the base avoidance zone on the base.

9. The piezoelectric MEMS microphone as described in claim 6 , wherein the gasket further comprises a plurality of support pads laid along the plurality of support beams separately; two sides of the support pads along the axial directions thereof and the support beams form support beam avoidance zones respectively; and the side parts of the free ends separately cover the support beam avoidance zones.

10. The piezoelectric MEMS microphone as described in claim 7 , wherein the gasket further comprises a plurality of support pads laid along the plurality of support beams separately; two sides of the support pads along the axial directions thereof and the support beams form support beam avoidance zones respectively; and the side parts of the free ends separately cover the support beam avoidance zones.

11. The piezoelectric MEMS microphone as described in claim 9 , wherein the gasket further comprises a middle fixed pad arranged between the intermediate fixing plate and the support column; one ends of the support pads are connected with the edge fixing pad and the other ends are connected with the middle fixed pad; and the middle fixed pad, two adjacent support pads and the edge fixing pad define one second through hole corresponding to one sub-cavity.

12. The piezoelectric MEMS microphone as described in claim 10 , wherein the gasket further comprises a middle fixed pad arranged between the intermediate fixing plate and the support column; one ends of the support pads are connected with the edge fixing pad and the other ends are connected with the middle fixed pad; and the middle fixed pad, two adjacent support pads and the edge fixing pad define one second through hole corresponding to one sub-cavity.

13. The piezoelectric MEMS microphone as described in claim 6 , further comprising a plurality of restraining elements, wherein one ends of the restraining elements are connected with the free ends; and the other ends are connected with the ring base or the limit element or the gasket.

14. The piezoelectric MEMS microphone as described in claim 7 , further comprising a plurality of restraining elements, wherein one ends of the restraining elements are connected with the free ends; and the other ends are connected with the ring base or the limit element or the gasket.

Assignees

• Aac Acoustic Tech Shenzhen Co Ltd

Inventors

• Duan Lian
• Zhang Rui
• Chen Zhiyuan

Classifications

• H04R7/06 Primary

  comprising a plurality of sections or layers · CPC title

• H04R2201/003

  Mems transducers or their use · CPC title

• H04R7/18

  at the periphery · CPC title

• H04R19/04

  Microphones (H04R19/01 takes precedence) · CPC title

• B81B2201/0257

  Microphones or microspeakers · CPC title