Bone conduction microphone

Abstract

The utility model provides a bone conduction microphone, which comprises a circuit board, a shell and a vibration assembly, wherein the shell is connected with the circuit board in a covering manner to form an accommodating space, the vibration assembly is arranged in the accommodating space, and the accommodating space is divided into a first cavity and a second cavity by the vibration assembly; the bone conduction microphone further comprises an MEMS chip arranged in the first cavity, the circuit board is provided with a communication channel communicated with the first cavity and the second cavity, and vibration of the vibration assembly is conducted to one side of the MEMS chip through the first cavity. Vibration of the vibration assembly is conducted to the other side of the MEMS chip through the second cavity and the communication channel, the bone conduction microphone further comprises an ASIC chip electrically connected with the MEMS chip, and at least part of the ASIC chip is embedded in the circuit board. Compared with the prior art, the bone conduction microphone provided by the utility model can effectively improve the sensitivity and is beneficial to miniaturization development.

Description

[Technical Field]

[0001] This utility model relates to the field of acoustics and electricity, and in particular to a bone conduction microphone. [Background Technology]

[0002] Bone conduction microphones convert the slight vibrations of the head and neck bones caused by a person speaking into electrical signals. Unlike traditional microphones that collect sound through air conduction, they can reproduce sound with high clarity even in noisy environments, thus avoiding noise interference caused by sound transmission through the air and ensuring extremely high sound quality.

[0003] The bone conduction microphone of the related technology includes a housing, a circuit board that is covered by the housing to form a receiving space, and a MEMS chip, a vibration component, and an ASIC chip housed in the receiving space. The MEMS chip and the ASIC chip are used for sensing and are fixed on the circuit board. However, placing both the MEMS chip and the ASIC chip in the receiving space is not conducive to the development of miniaturization.

[0004] Therefore, it is necessary to study a new bone conduction microphone. [Utility Model Content]

[0005] The purpose of this invention is to provide a bone conduction microphone that can effectively improve sensitivity and facilitate miniaturization.

[0006] To achieve the above objectives, this utility model provides a bone conduction microphone, which includes a circuit board, a housing that covers the circuit board to form a receiving space, and a vibration component placed in the receiving space. The vibration component divides the receiving space into a first cavity and a second cavity. The vibration component and the circuit board enclose the first cavity, and the second cavity is spaced apart from the first cavity. The bone conduction microphone also includes a MEMS chip with a back cavity disposed in the first cavity. The circuit board has a communication channel connecting the first cavity and the second cavity. The vibration of the vibration component is conducted to one side of the MEMS chip through the first cavity, and the vibration of the vibration component is also conducted to the other side of the MEMS chip through the second cavity and the communication channel. The bone conduction microphone also includes an ASIC chip electrically connected to the MEMS chip, and the ASIC chip is at least partially embedded in the circuit board.

[0007] Preferably, the vibration assembly includes a vibrating element that is opposite to and spaced apart from the circuit board, and a frame connecting the vibrating element and the circuit board. The vibrating element includes a membrane fixed to the frame and a counterweight fixed to the membrane.

[0008] Preferably, the frame is a hollow ring structure and is spaced apart from the outer shell. The outer shell, the circuit board, and the vibration component enclose the second cavity, and the frame, the vibration component, and the circuit board enclose the first cavity.

[0009] Preferably, the circuit board includes a base plate and a surrounding wall connected to the periphery of the base plate. The surrounding wall is a hollow annular structure. One end of the surrounding wall is connected to the vibration component, and the other end is connected to the base plate. The vibration component is sandwiched between the outer shell and the surrounding wall. The outer shell and the vibration component together form the second cavity. The vibration component has a through hole connecting the second cavity and the communicating channel. The communicating channel passes through the surrounding wall and communicates with the back cavity through the base plate. Preferably, the MEMS chip is fixed to the circuit board. The communicating channel includes a first through hole communicating with the back cavity, a second through hole spaced apart from the first through hole and communicating with the second cavity, and a communicating cavity located inside the circuit board and communicating with the first through hole and the second through hole.

[0010] Preferably, the circuit board includes a first circuit board, a second circuit board, and a third circuit board stacked sequentially. The first circuit board is closer to the vibration component than the third circuit board. The MEMS chip, the vibration component, and the housing are fixedly connected to the first circuit board. The first through hole and the second through hole are disposed on the first circuit board, and the connecting cavity and the ASIC are disposed on the second circuit board.

[0011] Preferably, the circuit board has a single-layer structure.

[0012] Preferably, the ASIC chip is completely embedded in the circuit board.

[0013] Preferably, the bone conduction microphone includes bonding gold wires electrically connected to the MEMS chip and internal traces disposed in the circuit board, wherein the internal traces are electrically connected to both the bonding gold wires and the ASIC chip.

[0014] Preferably, the bone conduction microphone includes bonding gold wires electrically connected to the MEMS chip, pads disposed on the circuit board and electrically connected to the bonding gold wires, and metallized vias disposed in the circuit board, wherein the metallized vias are electrically connected to both the pads and the ASIC chip.

[0015] Preferably, the outer casing is provided with a vent hole that communicates with the second cavity.

[0016] The beneficial effects of this utility model are as follows: because a connecting channel is set in the circuit board, the vibration of the vibrating element can act on the diaphragm through two paths in a differential manner, thereby improving the sensitivity of the diaphragm vibration. At the same time, the ASIC chip is at least partially embedded in the circuit board, saving the internal space of the bone conduction microphone and facilitating the miniaturization of the bone conduction microphone. [Attached Image Description]

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0018] Figure 1 This is a schematic diagram of the structure of a first embodiment of the bone conduction microphone of this utility model;

[0019] Figure 2 This is a schematic diagram of the structure of a second embodiment of the bone conduction microphone of this utility model;

[0020] Figure 3 This is a schematic diagram of the structure of the bone conduction microphone of the present invention, embodiment three.

Detailed Implementation Methods

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0022] Please refer to Figure 1 This is a bone conduction microphone according to a first embodiment of the present invention, comprising a circuit board 3, a housing 1 that covers the circuit board 3 to form a receiving space 100, and a vibration component 5 and a MEMS chip 7 disposed in the receiving space 100. The vibration component 5 divides the receiving space 100 into a first cavity 103 and a second cavity 101. The vibration component 5 and the circuit board 1 enclose the first cavity 103, and the second cavity 101 is spaced apart from the first cavity 103.

[0023] The vibration assembly 5 includes a vibrating element 51 positioned opposite and spaced apart from the circuit board 3, and a frame 53 connecting the vibrating element 51 and the circuit board 3. The frame 53 is a hollow ring structure. The frame 53, the vibrating element 51, and the circuit board 3 enclose a first cavity 103. The MEMS chip 7 is placed in the first cavity 103 and fixed to the circuit board 3. The back cavity 710 of the MEMS chip 7 is covered by the circuit board 3. The circuit board 3 has a connecting channel 30 that connects the back cavity 710 in the first cavity 103 and the second cavity 101. The vibration of the vibration assembly 5 is transmitted to one side of the MEMS chip 7 through the first cavity 103, and the vibration of the vibration assembly 5 is also transmitted to the other side of the MEMS chip 7 through the second cavity 101, the connecting channel 30, and the back cavity 710. This differentially improves the sensitivity of the MEMS chip 7.

[0024] Specifically, the connecting channel 30 includes a first through hole 301, a second through hole 302 spaced apart from the first through hole 301, and a connecting cavity 303 located inside the circuit board 3 and connecting the first through hole 301 and the second through hole 302. The first through hole 301 is connected to the back cavity 710, and the second through hole 302 is connected to the second cavity 101.

[0025] In this embodiment, the circuit board 3 has a multi-layer structure, comprising a first circuit board 31, a second circuit board 32, and a third circuit board 33 stacked sequentially. The first circuit board 31 is closer to the vibration component 5 than the third circuit board 33, i.e., the first circuit board 31 and the outer shell 1 enclose the receiving space 100. The MEMS chip 7, the vibration component 5, and the outer shell 1 are all fixedly connected to the same surface of the first circuit board 31, and the second circuit board 32 is sandwiched between the first circuit board 31 and the third circuit board 33. A first through hole 301 and a second through hole 302 are provided on the first circuit board 31, and a connecting cavity 303 is provided on the second circuit board 32. The outer shell 1, the first circuit board 31, and the vibration component 5 enclose a second cavity 101. In other embodiments, the circuit board can also be a single-layer structure, as long as the circuit board forms connecting channels that communicate with the second cavity and the back cavity respectively.

[0026] In addition, the vibrating element 51 includes a diaphragm 511 that is fixedly connected to the frame 53 and a counterweight 513 fixed to the diaphragm 511. The diaphragm 513 is an elastic element, and the counterweight 513 can enhance the vibration of the diaphragm 511. The counterweight 513 can be fixed on the side of the diaphragm 511 facing the first cavity 103, or it can be fixed on the side of the diaphragm 511 away from the first cavity 103, or counterweights 513 can be provided on both sides of the diaphragm 511.

[0027] The MEMS chip 7 includes a substrate 71 having the back cavity 710 and a capacitor structure 73 fixed on the substrate 71. The capacitor structure 73 includes a diaphragm 731 and a back plate 733 spaced apart. The substrate 71 is fixedly connected to the first circuit board 31. The MEMS chip 7 is used to sense vibrations and convert them into electrical signals.

[0028] The sensor unit 20 also includes an ASIC (Application Specific Integrated Circuit) chip 70 disposed in the package housing 21. The ASIC chip 70 is electrically connected to the sensor chip 22 to process the electrical signals generated by the sensor chip 22.

[0029] The bone conduction microphone also includes an ASIC (Application Specific Integrated Circuit) chip 9 electrically connected to the MEMS chip 7, allowing the circuit signal output by the MEMS chip 7 to be transmitted to the ASIC chip 9, processed, and output. The ASIC chip 9 can be fully embedded in the circuit board 3 or partially embedded therein, thus fully utilizing the internal space of the circuit board 3 and saving the storage space 100, which is beneficial for the miniaturization of the bone conduction microphone. The MEMS chip 7 and the ASIC chip 9 are electrically connected, and internal traces 8 are provided in the circuit board 3. The MEMS chip 7 achieves conductivity with the ASIC chip 9 by bonding gold wires 2 and internal traces 8.

[0030] In this embodiment, the vibration of the vibrating element 51 is transmitted to one side of the diaphragm 731 through the first cavity 103, and the vibration of the vibrating element 51 is also transmitted to the other side of the diaphragm 731 through the second cavity 101, the connecting channel 30 and the back cavity 710. Specifically, when the vibration signal transmitted through the bone is transmitted to the circuit board 3 and / or the housing 1, the vibration transmitted to the circuit board 3 and / or the housing 1 is transmitted to the vibrating element 51 via the frame 53 so that the vibrating element 51 vibrates in response to the vibration signal. The vibration of the vibrating element 51 causes changes in the air pressure of the first cavity 103 and the air pressure of the second cavity 101 (specifically, when the air pressure in the first cavity 103 increases, the air pressure in the second cavity 101 decreases; when the air pressure in the first cavity 103 decreases, the air pressure in the second cavity 101 increases). Thus, the vibration of the vibrating element 51 is transmitted to one side of the diaphragm 731 via the first cavity 103, and the vibration of the vibrating element 51 is also transmitted to the other side of the diaphragm 731 via the second cavity 101, the acoustic channel 30, and the back cavity 710. Therefore, the vibration of the vibrating element 51 can act on the diaphragm 731 in a differential manner through two paths, thereby improving the vibration sensitivity of the diaphragm 731. The vibration of the diaphragm 731 causes a change in the capacitance between the diaphragm 731 and the backplate 733, which is transmitted to the ASIC chip 9 to output an electrical signal, thereby converting the vibration signal transmitted through the bone into an electrical signal.

[0031] In addition, the outer shell 1 is also provided with a vent 10 communicating with the second cavity 101. The vent 10 communicates with the external environment. Thus, by providing the vent 10, when assembling the vibration component 5 and the MEMS chip 7, the failure of the vibration component 5 or the MEMS chip 7 due to the air pressure difference between the inner and outer spaces of the outer shell 1 or the vibration component 5 can be avoided, thereby reducing the assembly difficulty of the bone conduction microphone. In addition, the vent 10 can also be used to balance the air pressure of the second cavity 101. In this embodiment, the outer shell 1 includes a cover plate 13 and a hollow annular sidewall 11, and the vent 10 is provided in the cover plate 13.

[0032] like Figure 2The diagram shows a bone conduction microphone according to a second embodiment of the present invention. The difference between the second embodiment and the first embodiment lies only in that: in the second embodiment, a pad 82' is provided on the surface of the circuit board 3', and the pad 82' is located on the first circuit board 31'. The first circuit board 31' also has a metallized via 81' that electrically connects the pad 82' and the ASIC chip 9'. On one hand, the MEMS chip 7' is electrically connected to the pad 82' through a bonding gold wire 2'; on the other hand, the ASIC chip 9' is electrically connected to the pad 82' through the metallized via 81', thus achieving the electrical connection between the MEMS chip 7' and the ASIC chip 9'. The ASIC chip 9' is embedded in the second circuit board 32', and the metallized via 81' penetrates the first circuit board 31'. In this embodiment, the circuit board 3' is multi-layered, i.e., the first circuit board 31', the second circuit board 32', and the third circuit board 33' are stacked. In other embodiments, the circuit board can also be a single-layer structure.

[0033] like Figure 3The image shows a bone conduction microphone according to the third embodiment of this utility model. The difference between the third embodiment and the second embodiment is only that in the third embodiment, the circuit board 3” includes a base plate 35” and a surrounding wall 34 connected to the periphery of the base plate 35”, and the ASIC chip 9” is embedded in the circuit board 3”. The surrounding wall 34” is a hollow ring structure. One end of the surrounding wall 34” is connected to the vibration component 5”, and the other end is connected to the base plate 35”. The vibration component 5” is sandwiched between the outer shell 1” and the surrounding wall 34”. The outer shell 1” and the vibration component 5” together form the second cavity 101. The vibration component 5” is provided with a through hole 510 connecting the second cavity 101” and the connecting channel 30”. The connecting channel 30” includes a hole 510 provided in the surrounding wall. The third through hole 340” of 34” and the second through hole 302”, the connecting cavity 303”, and the first through hole 301” are provided on the bottom plate 35”. That is, the vibration of the vibration component 5” is transmitted to one side of the diaphragm 731” through the first cavity 103”, and the vibration of the vibration component 5” is also transmitted to the other side of the diaphragm 731” through the through hole 510”, the third through hole 340”, the second through hole 302”, the connecting cavity 303”, the first through hole 301”, and the back cavity 710”. The vibration assembly 5” includes a vibrating element 51” positioned opposite and spaced apart from the circuit board 3” and a frame 53 connecting the vibrating element 51” and the circuit board 3”. The vibrating element 51” includes a membrane 511” fixedly attached to the frame 53” and a counterweight 513 fixed to the membrane 511”. The frame 53” is a hollow ring structure. In this embodiment, the frame 53” is a gasket, preferably a metal gasket. A through hole 510 passes through the membrane 511” and the gasket. The membrane 511” is sandwiched between the frame 53” and the outer shell 1”. The membrane 511” and the outer shell 1” enclose to form a second cavity 101. The vibration assembly 5” and the circuit board 3” enclose to form a first cavity 203. In this embodiment, the base plate is a single-layer structure, and the ring wall and the base plate are separate structures. In other embodiments, the base plate may also be a multi-layer structure or the ring wall and the base plate may be an integral structure.

[0034] The above description is merely an embodiment of this utility model. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this utility model, but these improvements all fall within the protection scope of this utility model.

Claims

1. A bone conduction microphone, comprising a circuit board, a housing that covers the circuit board to form a receiving space, and a vibration component disposed in the receiving space, the vibration component dividing the receiving space into a first cavity and a second cavity, the vibration component and the circuit board enclosing the first cavity, the second cavity being spaced apart from the first cavity, the bone conduction microphone further comprising a MEMS chip with a back cavity disposed in the first cavity, characterized in that: The circuit board is provided with a communication channel connecting the first cavity and the second cavity. The vibration of the vibration component is transmitted to one side of the MEMS chip through the first cavity. The vibration of the vibration component is also transmitted to the other side of the MEMS chip through the second cavity and the communication channel. The bone conduction microphone also includes an ASIC chip electrically connected to the MEMS chip. The ASIC chip is at least partially embedded in the circuit board.

2. The bone conduction microphone according to claim 1, characterized in that, The vibration assembly includes a vibrating element that is opposite to and spaced apart from the circuit board, and a frame connecting the vibrating element and the circuit board. The vibrating element includes a membrane fixed to the frame and a counterweight fixed to the membrane.

3. The bone conduction microphone according to claim 2, characterized in that, The frame is a hollow ring structure and is spaced apart from the outer shell. The outer shell, the circuit board, and the vibration component enclose the second cavity, and the frame, the vibration component, and the circuit board enclose the first cavity.

4. The bone conduction microphone according to claim 1, characterized in that, The circuit board includes a base plate and a surrounding wall connected to the periphery of the base plate. The surrounding wall is a hollow ring structure. One end of the surrounding wall is connected to the vibration component, and the other end is connected to the base plate. The vibration component is sandwiched between the outer shell and the surrounding wall. The outer shell and the vibration component together form the second cavity. The vibration component has a through hole that connects the second cavity and the connecting channel. The connecting channel passes through the surrounding wall and communicates with the back cavity through the base plate.

5. The bone conduction microphone according to claim 1, characterized in that, The MEMS chip is fixed to the circuit board, and the communication channel includes a first through hole communicating with the back cavity, a second through hole spaced apart from the first through hole and communicating with the second cavity, and a communication cavity located inside the circuit board and communicating with the first through hole and the second through hole.

6. The bone conduction microphone according to claim 5, characterized in that, The circuit board includes a first circuit board, a second circuit board, and a third circuit board stacked in sequence. The first circuit board is closer to the vibration component than the third circuit board. The MEMS chip, the vibration component, and the housing are fixedly connected to the first circuit board. The first through hole and the second through hole are located on the first circuit board. The connecting cavity and the ASIC are located on the second circuit board.

7. The bone conduction microphone according to claim 1, characterized in that, The circuit board has a single-layer structure.

8. The bone conduction microphone according to claim 1, characterized in that, The ASIC chip is completely embedded in the circuit board.

9. The bone conduction microphone according to claim 8, characterized in that, The bone conduction microphone includes bonding gold wires electrically connected to the MEMS chip and internal traces disposed in the circuit board. The internal traces are electrically connected to both the bonding gold wires and the ASIC chip.

10. The bone conduction microphone according to claim 8, characterized in that, The bone conduction microphone includes bonding gold wires electrically connected to the MEMS chip, pads on the circuit board electrically connected to the bonding gold wires, and metallized vias placed in the circuit board. The metallized vias are electrically connected to both the pads and the ASIC chip.

11. The bone conduction microphone according to claim 1, characterized in that, The outer casing is provided with a vent hole that communicates with the second cavity.

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