Bone conduction microphone

Abstract

A bone conduction microphone, comprising: a housing; a single-layer circuit board covered with the housing to form an accommodating space, the circuit board being integrated with an acoustic channel; a vibration assembly dividing the accommodating space into a first cavity and a second cavity and enclosed with the circuit board to form the second cavity; and an MEMS chip arranged in the second cavity and fixed to the circuit board, wherein the MEMS chip is provided with a back cavity, the acoustic channel is communicated with the first cavity and the back cavity, vibration of the vibration assembly is conducted to one side of the MEMS chip by means of the first cavity, the acoustic channel and the back cavity, and the vibration of the vibration assembly is also conducted to the other side of the MEMS chip by means of the second cavity. The bone conduction microphone configured in this way uses the single-layer circuit board integration method to achieve a bottom sound channel, thereby effectively reducing a product's height to meet the design requirements for product height specifications, lowering the cost of circuit board materials and simplifying the packaging production process.

Description

bone conduction microphone Technical Field

[0001] The present invention relates to the field of acoustics and electricity, and in particular to a bone conduction microphone. Background Art

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

[0003] Related art bone conduction microphones include a first circuit board and a second circuit board, which are stacked and secured by welding to form a hollow-cavity circuit board structure. This hollow-cavity structure is used in applications where two cavities need to be connected. However, this type of bone conduction microphone requires two circuit boards to form a hollow-cavity circuit board, which makes it unsuitable for design requirements with reduced product height and increases circuit board material costs and packaging production processes.

[0004] Therefore, it is necessary to study a new bone conduction microphone. Summary of the Invention

[0005] The present invention aims to solve the problems that bone conduction microphones do not meet the design requirements of reducing product height and increase circuit board material costs and packaging production processes, and provides a bone conduction microphone with a new structure.

[0006] To achieve the above object, the present invention provides a bone conduction microphone, comprising:

[0007] shell;

[0008] A single-layer circuit board is connected to the housing cover to form a receiving space, and the circuit board is integrated with an acoustic channel;

[0009] a vibration component disposed in the receiving space and dividing the receiving space into a first cavity and a second cavity, wherein the vibration component and the circuit board enclose the second cavity;

[0010] A MEMS chip is disposed in the second cavity and fixed to the circuit board. The MEMS chip has a back cavity. The acoustic channel connects the first cavity and the back cavity. The vibration of the vibration component is transmitted to one side of the MEMS chip through the first cavity, the acoustic channel and the back cavity. The vibration of the vibration component is also transmitted to the other side of the MEMS chip through the second cavity.

[0011] As an improvement, the acoustic channel includes a first sound hole connected to the first cavity, a second sound hole spaced apart from the first sound hole and connected to the back cavity, and a sound channel arranged inside the circuit board and connecting the first sound hole and the second sound hole.

[0012] As an improvement, the vibration assembly includes a vibration member opposite to and spaced from the circuit board, and a frame connecting the vibration member and the circuit board, wherein the frame, the vibration member and the circuit board enclose and form the second cavity.

[0013] As an improvement, the vibration member includes a membrane body fixed to the frame and a counterweight block fixed to the membrane body.

[0014] As an improvement, the counterweight is fixed to a side of the membrane body facing the first cavity.

[0015] As an improvement, the counterweight is fixed to a side of the membrane body facing the second cavity.

[0016] As an improvement, the bone conduction microphone further includes an ASIC chip electrically connected to the MEMS chip, and the ASIC chip is disposed in the second cavity and fixed to the circuit board.

[0017] As an improvement, the MEMS chip includes a base fixed on the circuit board and a capacitor assembly fixed on the side of the base away from the circuit board, the back cavity is formed on the base, the capacitor assembly includes a diaphragm and a back plate spaced apart from the diaphragm, the diaphragm is arranged on the side of the back plate facing the back cavity, and the back plate is provided with a through hole passing through it along the vibration direction of the diaphragm.

[0018] As an improvement, the shell is a metal shell with electromagnetic shielding function.

[0019] The beneficial effects of the present invention are: on the one hand, by adopting a single-layer circuit board integration method to realize the bottom acoustic channel, the product height can be effectively reduced to meet the design requirements of the product height specification, while also reducing the circuit board material cost and the packaging production process; on the other hand, since the vibration of the vibration component is transmitted to one side of the MEMS chip through the first cavity, the acoustic channel and the back cavity, and the vibration of the vibrating part is also transmitted to the other side of the MEMS chip through the second cavity, the vibration of the vibration component can act on the MEMS chip in a differential manner through two paths respectively, thereby improving the sensitivity of the MEMS chip. At the same time, the first cavity, the acoustic channel and the back cavity can increase the back cavity of the bone conduction microphone, thereby effectively improving the sensitivity of the bone conduction microphone and reducing the noise of the bone conduction microphone to effectively improve the signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a schematic structural diagram of a bone conduction microphone according to a first embodiment of the present invention.

[0021] FIG2 is a schematic diagram of the structure of the circuit board in the bone conduction microphone shown in FIG1 .

[0022] FIG3 is a schematic structural diagram of a second embodiment of a bone conduction microphone according to the present invention. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below with reference to FIG1 to FIG3. Example 1

[0024] Please refer to FIG. 1 and FIG. 2 , the bone conduction microphone of the present invention includes a housing 1 , a single-layer circuit board 3 , a vibration component 5 and a MEMS chip 7 .

[0025] The housing 1 and the circuit board 3 are connected to form a receiving space 100 .

[0026] As shown in FIG. 1 , the housing 1 includes a bottom wall 11 opposite to and spaced from the circuit board 3 , and a side wall 13 extending from a periphery of the bottom wall 11 to the circuit board 3 and connected to the circuit board 3 .

[0027] The circuit board 3 is integrated with an acoustic channel 3A.

[0028] The acoustic channel 3A includes a first acoustic hole 3B, a second acoustic hole 3C spaced apart from the first acoustic hole 3B, and an acoustic channel 3D provided inside the circuit board 3 and connecting the first acoustic hole 3B and the second acoustic hole 3C.

[0029] The vibration assembly 5 is disposed in the receiving space 100 and divides the receiving space 100 into a first cavity 101 and a second cavity 103 .

[0030] The vibration component 5 , the circuit board 3 and the housing 1 enclose a first cavity 101 . The first sound hole 3B is in communication with the first cavity 101 .

[0031] The vibration component 5 and the circuit board 3 enclose and form a second cavity 103 .

[0032] The vibration assembly 5 includes a vibration member 51 disposed opposite to and spaced apart from the circuit board 3 , and a frame 53 connecting the vibration member 51 and the circuit board 3 .

[0033] The frame 53 , the vibrating element 51 , the circuit board 3 and the housing 1 together form a first cavity 101 .

[0034] The frame 53 , the vibrating element 51 and the circuit board 3 together form a second cavity 103 .

[0035] The MEMS chip 7 is disposed in the second cavity 103 and fixed to the circuit board 3 .

[0036] The MEMS chip 7 has a back cavity 711, which is connected to the second acoustic hole 3C. That is, the acoustic channel 3A connects the first cavity 101 and the back cavity 711. The vibration of the vibration component 5 is transmitted to one side of the MEMS chip 7 through the first cavity 101, the acoustic channel 3A, and the back cavity 711. The vibration of the vibrating element 51 is also transmitted to the other side of the MEMS chip 7 through the second cavity 103.

[0037] The MEMS chip 7 includes a substrate 71 fixed on the circuit board 3 and a capacitor component 73 fixed on a side of the substrate 71 away from the circuit board 3 .

[0038] A back cavity 711 is formed on the substrate 71 .

[0039] The capacitor assembly 73 includes a diaphragm 731 and a back plate 733 spaced apart from the diaphragm 731. The diaphragm 731 is disposed on the side of the back plate 733 facing the back cavity 711. The back plate 733 is provided with a through hole (not shown) passing through the diaphragm 731 along the vibration direction of the diaphragm 731.

[0040] Among them, the vibration of the vibrating member 51 is transmitted to one side of the diaphragm 731 through the first cavity 101, the first sound hole 3B, the acoustic channel 3A, the second sound hole 3C, and the back cavity 711. The vibration of the vibrating member 51 is also transmitted to the other side of the diaphragm 731 through the second cavity 103 and the through-hole of the back plate 733. 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 member 51 through the frame 53 so that the vibrating member 51 of the vibration assembly 5 vibrates in response to the vibration signal. The vibration of the vibrating member 51 will cause the air pressure in the first cavity 101 and the air pressure in the second cavity 103 to change (specifically, when the air pressure in the first cavity 101 increases, the air pressure in the second cavity 103 decreases; when the air pressure in the first cavity 101 decreases, The air pressure in the second cavity 103 increases), so that the vibration of the vibrating member 51 is transmitted to one side of the diaphragm 731 through the first cavity 101, the first sound hole 3B, the acoustic channel 3A, the second sound hole 3C, and the back cavity 711, and the vibration of the vibrating member 51 is also transmitted to the other side of the diaphragm 731 through the second cavity 103 and the through hole of the back plate 733. Therefore, the vibration of the vibrating member 51 can act on the diaphragm 731 in a differential manner through two paths, thereby improving the sensitivity of the vibration of the diaphragm 731. The vibration of the diaphragm 731 will cause the capacitance of the capacitor component 73 to change, thereby converting the vibration signal transmitted through the bone into an electrical signal. Among them, the electrical signal picked up by the MEMS chip 7 is output through the circuit board 3.

[0041] It should be noted that, in order for the frame 53, the vibrating member 51, the circuit board 3, and the housing 1 to enclose the first cavity 101, and for the vibration of the vibrating member 51 to be transmitted to one side of the diaphragm 731 via the first cavity 101, the acoustic channel 3A, and the back cavity 711, the bottom wall 11 is spaced apart from the vibrating member 51 along its vibration direction, and the side wall 13 is at least partially spaced apart from the frame 53. As shown in the figure, the side wall 13 is entirely spaced apart from the frame 53.

[0042] The vibrating member 51 includes a membrane 511 fixed to a frame 53 and a counterweight 513 fixed to the membrane 511. The counterweight can increase the amplitude of the vibration of the membrane 511, thereby increasing the amplitude of the air pressure changes in the first chamber 101 and the second chamber 103 caused by the vibration of the vibrating member 51.

[0043] As shown in FIG. 1 , the counterweight 513 is fixed to the side of the membrane 511 facing the second cavity 103 .

[0044] It should be noted that when the counterweight 513 is fixed to the side of the membrane 511 facing the second cavity 103 , in order to prevent the MEMS chip 7 from affecting the vibration of the counterweight 513 , there should be a sufficient distance between the counterweight 513 and the MEMS chip 7 .

[0045] In this embodiment, the housing 1 is preferably a metal shell with electromagnetic shielding capabilities. For example, the electromagnetic shielding housing 1 can be made of a conductive metal. This allows the housing 1 to protect the internal structure of the bone conduction microphone while also shielding it from external electromagnetic waves.

[0046] To further improve the sensitivity of the bone conduction microphone, this embodiment also includes an ASIC chip 9 electrically connected to the MEMS chip 7. ASIC chip 9 is located within the second cavity 103 and secured to the circuit board 3. ASIC chip 9 provides an external bias for the MEMS chip 7. This effective bias ensures that the MEMS chip 7 maintains stable acoustic sensitivity and electrical parameters across the entire operating temperature range. It also supports microphone designs with varying sensitivities, providing greater flexibility and reliability.

[0047] In this embodiment, the ASIC chip 9 and the MEMS chip 7 are electrically connected via a conductive wire 8 . Example 2

[0048] Please refer to FIG. 3 . The only difference between the second embodiment and the first embodiment is that the counterweight 513 is fixed to the side of the membrane 511 facing the first cavity 101 .

[0049] It should be noted that when the counterweight 513 can also be fixed to the side of the membrane 511 facing the first cavity 101, in order to avoid the bottom wall 11 of the shell 1 affecting the vibration of the counterweight 513, there should be a sufficient distance between the counterweight 513 and the bottom wall 11.

[0050] 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 bone conduction microphone, characterized in that: it includes: a housing; a single-layer circuit board, which is lid-connected to the housing to form a receiving space, and the circuit board is integrated with an acoustic channel; a vibration component, which is arranged in the receiving space and divides the receiving space into a first cavity and a second cavity. Among them, the vibration component and the circuit board enclose the second cavity; a MEMS chip, which is arranged in the second cavity and fixed to the circuit board. The MEMS chip has a back cavity. The acoustic channel communicates the first cavity and the back cavity. The vibration of the vibration component is conducted to one side of the MEMS chip through the first cavity, the acoustic channel and the back cavity. The vibration of the vibration component is also conducted to the other side of the MEMS chip through the second cavity.

2. The bone conduction microphone according to claim 1, characterized in that: the acoustic channel includes a first sound hole communicating with the first cavity, a second sound hole spaced from the first sound hole and communicating with the back cavity, and a sound channel arranged inside the circuit board and communicating the first sound hole and the second sound hole.

3. The bone conduction microphone according to claim 1, characterized in that: the vibration component includes a vibration piece opposite to and spaced from the circuit board and a frame connecting the vibration piece and the circuit board. Among them, the frame, the vibration piece and the circuit board enclose the second cavity.

4. The bone conduction microphone according to claim 3, characterized in that: the vibration piece includes a membrane body fixed to the frame and a counterweight fixed to the membrane body.

5. The bone conduction microphone according to claim 4, characterized in that: the counterweight is fixed to one side of the membrane body facing the first cavity.

6. The bone conduction microphone according to claim 4, characterized in that: the counterweight is fixed to one side of the membrane body facing the second cavity.

7. The bone conduction microphone according to claim 1, characterized in that, the bone conduction microphone further includes an ASIC chip electrically connected to the MEMS chip. The ASIC chip is arranged in the second cavity and fixed to the circuit board.

8. The bone conduction microphone according to claim 1, characterized in that, the MEMS chip includes a substrate fixed to the circuit board and a capacitor component fixed to the side of the substrate away from the circuit board. The back cavity is formed on the substrate. The capacitor component includes a vibrating membrane and a back plate spaced from the vibrating membrane. The vibrating membrane is arranged on the side of the back plate facing the back cavity. The back plate is provided with a through hole penetrating therethrough along the vibration direction of the vibrating membrane.

9. The bone conduction microphone according to claim 1, characterized in that, the housing is a metal shell with electromagnetic shielding function.

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