WO2022061979A1

WO2022061979A1 - Bone conduction microphone

Info

Publication number: WO2022061979A1
Application number: PCT/CN2020/120595
Authority: WO
Inventors: 张金宇
Original assignee: 瑞声声学科技(深圳)有限公司
Priority date: 2020-09-25
Filing date: 2020-10-13
Publication date: 2022-03-31
Also published as: CN213342680U

Abstract

Provided is a bone conduction microphone. The bone conduction microphone comprises a circuit board assembly, a vibration assembly fixed to the circuit board assembly, a MEMS chip electrically connected to the circuit board assembly and provided with a back cavity, and an ASIC chip electrically connected to the circuit board assembly; and same further comprises a metal cover plate stacked on the circuit board assembly. The circuit board assembly comprises a top face attached to the metal cover plate and an accommodating recess provided in the top face and recessed in the direction away from the metal cover plate, and the metal cover plate is fixed between the vibration assembly and the circuit board assembly; the MEMS chip and the ASIC chip are fixed on the metal cover plate, and the MEMS chip and the ASIC chip are positioned in the accommodating recess; and a sound hole which is in communication with the back cavity is provided in the metal cover plate in a penetrating manner. The present disclosure can reduce the thickness of a bone conduction microphone by approximately 0.1 mm, and facilitates the miniaturization of products.

Description

A bone conduction microphone

technical field

The utility model belongs to the technical field of microphones, in particular to a bone conduction microphone.

Background technique

With the advancement of science and technology, there is a microphone on the market that uses bone conduction to realize sound transmission, which can achieve clear sound restoration in a noisy environment, avoid noise interference caused by air-borne sound, and ensure high sound quality. In the related art, the MEMS chip of the bone conduction microphone is attached to the circuit board. Since the circuit board itself has a large thickness, the microphone as a whole occupies a large space.

technical problem

The purpose of the present invention is to provide a bone conduction microphone, which aims to reduce the size of the bone conduction microphone.

technical solutions

The technical scheme of the present invention is as follows: a bone conduction microphone, comprising a circuit board assembly, a vibration assembly fixed to the circuit board assembly, a MEMS chip electrically connected to the circuit board assembly and having a back cavity, and a MEMS chip connected to the circuit board assembly. An ASIC chip electrically connected to a circuit board assembly, the bone conduction microphone further includes a metal cover plate stacked on the circuit board assembly, the circuit board assembly including a top surface that is attached to the metal cover plate and a The top surface is recessed in the direction away from the metal cover plate, the metal cover plate is fixed between the vibration component and the circuit board component; the MEMS chip and the ASIC chip are fixed on the the metal cover plate and the MEMS chip and the ASIC chip are located in the receiving groove; the metal cover plate is provided with an acoustic hole communicating with the back cavity, and the vibration component is arranged on the metal cover plate The cover plate is away from the side of the back cavity.

Further, the bone conduction microphone further includes a base plate sandwiched between the metal cover plate and the vibration component, the base plate is provided with a first hollow portion, and the first hollow portion communicates with the sound hole. .

Further, the circuit board assembly includes a first circuit board attached to the metal cover plate, a second circuit board attached to the side of the first circuit board away from the metal cover plate, and a second circuit board attached to the side of the first circuit board away from the metal cover plate. a third circuit board on the side of the second circuit board away from the first circuit board, a second hollow part is formed on the first circuit board, and a second hollow part is formed on the second circuit board The connected third hollow part, the second hollow part and the third hollow part together form the receiving groove.

Further, the thickness of the metal cover plate is smaller than the thicknesses of the first circuit board, the second circuit board and the third circuit board.

Further, the first circuit board, the second circuit board and the third circuit board are bonded, fixed and electrically connected.

Further, the MEMS chip and the ASIC chip are bonded and fixed to the metal cover plate.

Further, the vibration assembly includes a bone conduction shell covering the side of the base plate away from the circuit board assembly to receive external vibration, a vibration membrane sandwiched between the bone conduction shell and the base plate, and a fixed Mass on the diaphragm.

Further, the MEMS chip has a through hole facing the substrate and communicating with the back cavity, the through hole is opposite to the acoustic hole and the diameter of the acoustic hole is smaller than that of the through hole.

Further, the acoustic hole is directly opposite to the through hole.

Further, the mass block is fixed on the side of the diaphragm away from the metal cover plate.

beneficial effect

The beneficial effects of the present invention are as follows: in the bone conduction microphone of the present invention, a layer of metal cover plate is stacked on the circuit board assembly, and the top surface of the circuit board assembly is recessed toward the direction away from the metal cover plate to form a receiving groove, the MEMS chip and the ASIC The chip is fixed in the receiving slot. Compared with the related art, since the thickness of the circuit board assembly includes the thickness of the MEMS chip and the ASIC chip, the MEMS chip and the ASIC chip do not occupy another thickness, so the thickness of the bone conduction microphone can be reduced. , reducing the thickness of about 0.1mm, which is conducive to the miniaturization of products; when the vibration signal transmitted through the bone is transmitted to the bone conduction microphone, the vibration component vibrates in response to the vibration signal, so that the gap between the MEMS chip and the vibration component The gas in the cavity is compressed and stretched, and the pressure changes periodically. The changed pressure signal is picked up by the MEMS chip and converted into an electrical signal. The ASIC chip 3 further amplifies the signal to realize the transmission of sound.

Description of drawings

1 is a schematic diagram of the overall structure of a bone conduction microphone provided by an embodiment of the present invention;

2 is a schematic diagram of an exploded structure of a bone conduction microphone provided by an embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view in the direction A-A of FIG. 1 .

Embodiments of the present invention

The present utility model will be further described below with reference to the accompanying drawings and embodiments.

Example:

Referring to FIGS. 1 to 3 , a bone conduction microphone provided by an embodiment of the present invention includes a circuit board assembly 1 , a vibration assembly 5 fixed to the circuit board assembly 1 , and a vibration assembly 5 that is electrically connected to the circuit board assembly 1 and has a back The MEMS chip 2 of the cavity 21 and the ASIC chip 3 electrically connected to the circuit board assembly 1 .

As shown in FIG. 2 and FIG. 3 , the bone conduction microphone of this embodiment further includes a metal cover 4 stacked on the circuit board assembly 1 , and the circuit board On the top surface 112 and the receiving groove 8 recessed in the direction away from the metal cover plate 4, the metal cover plate 4 is fixed between the vibration component 5 and the circuit board component 1, the MEMS chip 2 and the ASIC chip 3 are fixed on the metal cover plate 4 and The MEMS chip 2 and the ASIC chip 3 are located in the receiving groove 8 , and an acoustic hole 41 communicating with the back cavity 21 is formed through the metal cover plate 4 .

In the bone conduction microphone of the present invention, a layer of metal cover plate 4 is stacked on the circuit board assembly 1, and the top surface 112 of the circuit board assembly 1 is recessed in the direction away from the metal cover plate 4 to form a receiving groove 8, a MEMS chip 2 and an ASIC chip 3 is fixed in the receiving groove 8. Compared with the related art, since the thickness of the circuit board assembly 1 includes the thickness of the MEMS chip 2 and the ASIC chip 3, the MEMS chip 2 and the ASIC chip 3 do not occupy another thickness, so it can be reduced The thickness dimension of the bone conduction microphone is reduced by about 0.1mm, which is conducive to the miniaturization of the product. When the vibration signal transmitted through the bone is transmitted to the bone conduction microphone of the present invention, the vibration component 5 vibrates in response to the vibration signal, so that the gas in the cavity between the MEMS chip 2 and the vibration component 5 is compressed and stretched , the pressure changes periodically, the changed pressure signal is picked up by the MEMS chip and converted into an electrical signal, and the ASIC chip 3 further amplifies the signal to realize the transmission of sound.

Specifically, the bone conduction microphone of this embodiment further includes a base plate 6 sandwiched between the metal cover plate 4 and the vibration component 5 , the base plate 6 is provided with a first hollow portion 61 , and the first hollow portion 61 communicates with the sound hole 41 . That is, the first hollow portion 61 , the sound hole 41 and the back cavity 21 are communicated with each other.

Specifically, the circuit board assembly 1 includes a first circuit board 11 attached to the metal cover plate 4 , a second circuit board 12 attached to the side of the first circuit board 11 away from the metal cover plate 4 , and a second circuit board attached to the second circuit A third circuit board 13 on the side of the board 12 away from the first circuit board 11 . The first circuit board 11 is provided with a second hollow portion 111 , and the second circuit board 12 is provided with a third hollow portion communicating with the second hollow portion 111 . part 121 , the second hollow part 111 and the third hollow part 121 together constitute the receiving groove 8 . It can be understood that the arrangement of the second hollow portion 111 and the third hollow portion 121 can not only constitute the receiving groove 8 for accommodating the MEMS chip 2 and the ASIC chip 3 , but also save the circuit manufacturing process and cost of the circuit board assembly. In this embodiment, the first circuit board 11 , the second circuit board 12 and the third circuit board 13 are bonded, fixed and electrically connected. Specifically, the first circuit board 11 , the second circuit board 12 , and the third circuit board 13 may be electrically connected through a conductive material, and the conductive material may be conductive glue, conductive solder paste, or other conductive materials, which are not covered in this embodiment. It is limited as long as the electrical connection between the first circuit board 11 , the second circuit board 12 and the third circuit board 13 can be realized.

In addition, the MEMS chip 2 and the ASIC chip 3 are bonded and fixed to the metal cover plate 4 . In this embodiment, the MEMS chip 2 and the ASIC chip 3 can be connected to the circuit board assembly 1 through wires. Since the MEMS chip 2 and the ASIC chip 3 are electrically connected to the circuit board assembly 1 respectively, the MEMS chip 2 and the ASIC chip 3 are electrically connected to each other. The ASIC chip 3 can receive the signal of the MEMS chip 2, of course, in other possible implementations, the MEMS chip 2 and the ASIC chip 3 can also be directly electrically connected through wires. The thickness of the metal cover plate 4 in this embodiment is relatively thin, and its thickness is smaller than the thicknesses of the first circuit board 11 , the second circuit board 12 and the third circuit board 13 , thereby further reducing the thickness of the bone conduction microphone.

As shown in FIG. 2 and FIG. 3 , the vibration component 5 of this embodiment includes a bone conduction shell 51 which is covered on the side of the base plate 6 away from the circuit board assembly 1 to receive external vibration, and is sandwiched between the bone conduction shell 51 and the base plate 6 . The vibrating membrane 52 in between and the mass block 53 fixed on the vibrating membrane 52 . Since the back cavity 21 of the MEMS chip 2 communicates with the first hollow portion 61 of the base plate 6 through the acoustic hole 41 on the metal cover plate 4 , when the vibration signal propagated through the bone is transmitted to the bone conduction shell 51 , the mass 53 responds to the vibration After the signal, the relative MEMS chip 2 is displaced, so that the gas in the cavity between the MEMS chip 2 and the mass 53 is compressed and stretched, the pressure changes periodically, and the changed pressure signal is picked up by the MEMS chip 2 and converted into an electrical signal , the ASIC chip 3 further amplifies the signal and realizes the transmission of sound.

Further, the MEMS chip 2 of this embodiment has a through hole 211 facing the substrate 6 , the through hole 211 is opposite to the acoustic hole 41 , the diameter of the acoustic hole 41 is smaller than that of the through hole 211 , and the acoustic hole 41 is directly opposite to the through hole 211 , which can make the MEMS chip 2 have a better effect of picking up the pressure signal. In addition, the mass block 53 in this embodiment is fixed on the side of the diaphragm 52 away from the metal cover plate 4 . In this embodiment, the bone conduction shell 51 and the diaphragm 52 are enclosed to form an accommodating space 7 for accommodating the mass block 53 . The height of the accommodating space 7 should be greater than the thickness dimension of the mass block 53 to avoid affecting the vibration of the mass block 53 . . The bone conduction shell 51 can also protect the internal structure of the bone conduction microphone, and the peripheral wall of the bone conduction shell 51 is flush with the edge of the circuit board assembly 1 , so that the bone conduction microphone is overall balanced and stable, and is more beautiful.

To sum up, in the bone conduction microphone of the present invention, a layer of metal cover plate 4 is stacked on the circuit board assembly 1 , and the top surface 112 of the circuit board assembly 1 is recessed in the direction away from the metal cover plate 4 to form a receiving groove 8 . The chip 2 and the ASIC chip 3 are fixed in the receiving groove 8. Compared with the related art, since the thickness of the circuit board assembly 1 includes the thickness of the MEMS chip 2 and the ASIC chip 3, the MEMS chip 2 and the ASIC chip 3 do not occupy another area. Therefore, the thickness of the bone conduction microphone can be reduced by about 0.1mm, which is conducive to the miniaturization of the product. When the vibration signal transmitted through the bone is transmitted to the bone conduction microphone of the present invention, the vibration component 5 vibrates in response to the vibration signal, so that the gas in the cavity between the MEMS chip 2 and the vibration component 5 is compressed and stretched , the pressure changes periodically, the changed pressure signal is picked up by the MEMS chip and converted into an electrical signal, and the ASIC chip 3 further amplifies the signal to realize the transmission of sound.

The above are only the embodiments of the present utility model. It should be pointed out that for those of ordinary skill in the art, improvements can be made without departing from the inventive concept of the present utility model, but these belong to The scope of protection of the utility model.

Claims

A bone conduction microphone, comprising a circuit board assembly, a vibration assembly fixed to the circuit board assembly, a MEMS chip electrically connected to the circuit board assembly and having a back cavity, and an ASIC chip electrically connected to the circuit board assembly , characterized in that: the bone conduction microphone further includes a metal cover plate stacked on the circuit board assembly, and the circuit board assembly includes a top surface attached to the metal cover plate and a a receiving groove recessed in the direction away from the metal cover plate, the metal cover plate is fixed between the vibration component and the circuit board component; the MEMS chip and the ASIC chip are fixed on the metal cover plate and the MEMS chip and the ASIC chip are located in the receiving groove; the metal cover plate is provided with a sound hole communicating with the back cavity, and the vibration component is arranged on the metal cover plate away from the side of the back cavity.
The bone conduction microphone according to claim 1, wherein the bone conduction microphone further comprises a base plate sandwiched between the metal cover plate and the vibration component, the base plate is provided with a first hollow portion, The first hollow portion communicates with the sound hole.
The bone conduction microphone according to claim 1, wherein the circuit board assembly comprises a first circuit board attached to the metal cover, and a first circuit board attached to the first circuit board away from the metal cover A second circuit board on one side and a third circuit board attached to the side of the second circuit board away from the first circuit board, the first circuit board is provided with a second hollow portion, the second circuit board is A third hollow portion communicated with the second hollow portion is formed on the circuit board, and the second hollow portion and the third hollow portion together form the receiving groove.
The bone conduction microphone according to claim 3, wherein the thickness of the metal cover plate is smaller than the thicknesses of the first circuit board, the second circuit board and the third circuit board.
The bone conduction microphone according to claim 3, wherein the first circuit board, the second circuit board and the third circuit board are adhesively fixed and electrically connected.
The bone conduction microphone according to claim 1, wherein the MEMS chip and the ASIC chip are bonded and fixed to the metal cover plate.
The bone conduction microphone according to claim 2, wherein the vibration component comprises a bone conduction shell which is covered on the side of the base plate away from the circuit board component and receives external vibration, and is sandwiched between the bone conduction shell. A vibrating membrane between the casing and the base plate and a mass block fixed on the vibrating membrane.
The bone conduction microphone according to claim 7, wherein the MEMS chip has a through hole facing the substrate and communicating with the back cavity, the through hole is opposite to the acoustic hole and the acoustic hole The pore size is smaller than the pore size of the through hole.
The bone conduction microphone according to claim 8, wherein the sound hole is directly opposite to the through hole.
The bone conduction microphone according to claim 7, wherein the mass block is fixed on a side of the diaphragm away from the metal cover.