Bone conduction microphone

Abstract

The present invention provides a bone conduction microphone, which includes: a housing; a circuit board, which is connected to the housing cover to form a receiving space, and the circuit board has an acoustic channel; a vibration component, which is arranged in the receiving space and divides the receiving space into a first conduction cavity and a second conduction cavity respectively connected to the acoustic channel, and the vibration component includes a vibration member opposite to the circuit board and arranged at intervals, and a frame connecting the vibration member and the circuit board, the frame, the vibration member and the circuit board are enclosed with the housing to form a first conduction cavity, and the frame, the vibration member and the circuit board are enclosed together to form a second conduction cavity; a MEMS chip, which is arranged in the second conduction cavity and fixed to the circuit board, and the MEMS chip has a diaphragm arranged between the circuit board and the vibration member, wherein the vibration of the vibration member is conducted to one side of the diaphragm through the first conduction cavity and the acoustic channel, and the vibration of the vibration member is also conducted to the other side of the diaphragm through the second conduction cavity. Compared with the related art, the bone conduction microphone of the present invention can effectively improve the sensitivity and signal-to-noise ratio.

Description

[Technical field]

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

[0002] Bone conduction microphones use the slight vibrations of the head and neck bones caused by speaking to convert them 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 noise interference caused by airborne sound and ensuring high sound quality. However, the sensitivity and signal-to-noise ratio of bone conduction microphones in related technologies are still insufficient. [Summary of the invention]

[0003] An object of the present invention is to provide a bone conduction microphone which can effectively improve sensitivity and signal-to-noise ratio.

[0004] In order to achieve the above object, the present invention provides a bone conduction microphone, comprising:

[0005] shell;

[0006] A circuit board is connected to the housing cover to form a receiving space, and the circuit board has an acoustic channel;

[0007] a vibration assembly, arranged in the receiving space and dividing the receiving space into a first conduction cavity and a second conduction cavity respectively connected to the acoustic channel, the vibration assembly comprising a vibration member opposite to and spaced from the circuit board and a frame connecting the vibration member and the circuit board, the frame, the vibration member and the circuit board and the housing enclose the first conduction cavity, and the frame, the vibration member and the circuit board together enclose the second conduction cavity;

[0008] A MEMS chip is arranged in the second conduction cavity and fixed to the circuit board, and the MEMS chip has a diaphragm arranged between the circuit board and the vibrating element, wherein the vibration of the vibrating element is transmitted to one side of the diaphragm via the first conduction cavity and the acoustic channel, and the vibration of the vibrating element is also transmitted to the other side of the diaphragm via the second conduction cavity.

[0009] Preferably, the circuit board includes an outer circuit board connected to the outer shell to form the receiving space and an inner circuit board fixed to the side of the outer circuit board facing the receiving space, and the frame, the vibrating member, the outer circuit board and the inner circuit board are combined with the outer shell to form the first conduction cavity, the frame is fixed to the side of the inner circuit board away from the outer circuit board, the acoustic channel includes a sound channel connected to the first conduction cavity and a sound hole connected to the sound channel, wherein at least one direction of the outer circuit board and the inner circuit board is recessed to form the sound channel, and the sound hole passes through the inner circuit board.

[0010] Preferably, the external circuit board comprises a first circuit board connected to the internal circuit board and the outer shell respectively, and a second circuit board fixed to a side of the first circuit board away from the internal circuit board, and the first circuit board is recessed to form the sound channel.

[0011] Preferably, the sound channel runs through the first circuit board.

[0012] Preferably, the vibration member includes a membrane body fixed to the frame and a mass block fixed to the membrane body.

[0013] Preferably, the mass block is fixed to a side of the membrane body facing the first conduction cavity; or, the mass block is fixed to a side of the membrane body facing the second conduction cavity.

[0014] Preferably, the frame includes a first frame fixed to the circuit board, a second frame connected to the vibrating member, and a partition sandwiched between the first frame and the second frame, the partition separates the second conduction cavity into a first cavity and a second cavity, a through hole connecting the first cavity and the second cavity is penetrated on the partition, and the MEMS chip is arranged in the second cavity.

[0015] Preferably, the orthographic projection of the through hole on the diaphragm is located within the range of the diaphragm.

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

[0017] Preferably, the MEMS chip includes a substrate having a back cavity and a capacitor assembly fixed on the substrate and covering the back cavity, the substrate is fixed on the circuit board, and the back cavity is connected to the acoustic channel, and the capacitor assembly includes the diaphragm and a back plate spaced apart from the diaphragm.

[0018] Compared with the related art, the embodiments of the present invention have at least the following beneficial effects: the bone conduction microphone provided by the embodiments of the present invention comprises: a housing; a circuit board, connected with the housing cover to form a receiving space, the circuit board having an acoustic channel; a vibration component, arranged in the receiving space and dividing the receiving space into a first conduction cavity and a second conduction cavity respectively connected to the acoustic channel, the vibration component comprising a vibration member opposite to the circuit board and arranged at intervals, and a frame connecting the vibration member and the circuit board, the frame, the vibration member and the circuit board and the housing enclose a first conduction cavity, and the frame, the vibration member and the circuit board jointly enclose a second conduction cavity; a MEMS chip, arranged in the second conduction cavity and fixed to the circuit board, the MEMS chip having a diaphragm arranged between the circuit board and the vibration member, wherein the vibration of the vibration member is conducted to one side of the diaphragm via the first conduction cavity and the acoustic channel, and the vibration of the vibration member is also conducted to the other side of the diaphragm via the second conduction cavity. Since the vibration of the vibrating member is transmitted to one side of the diaphragm through the first conduction cavity and the acoustic channel, and the vibration of the vibrating member is also transmitted to the other side of the diaphragm through the second conduction cavity, the vibration of the vibrating member can act on the diaphragm in a differential manner through two paths respectively, thereby improving the sensitivity of the diaphragm vibration. At the same time, the first conduction cavity and the acoustic channel 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

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0020] Figure 1 It is a structural schematic diagram of a bone conduction microphone embodiment 1 of the present invention;

[0021] Figure 2 for Figure 1 A schematic diagram of the structure of the inner and outer circuit boards of the bone conduction microphone shown;

[0022] Figure 3 It is a structural schematic diagram of a second embodiment of a bone conduction microphone of the present invention;

[0023] Figure 4 FIG. 1 is a schematic diagram of the structure of a bone conduction microphone according to a third embodiment of the present invention. [Specific implementation method]

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Embodiment 1

[0026] See also Figure 1 The bone conduction microphone includes a housing 1, a circuit board 3, a vibration component 5 and a MEMS chip 7.

[0027] The housing 1 and the circuit board 3 are connected to form a receiving space 100 .

[0028] like Figure 1 As shown, the housing 1 includes a bottom wall 11 opposite to and spaced from the circuit board 3 , and a side wall 13 extending from the periphery of the bottom wall 11 to the circuit board 3 and connected to the circuit board 3 .

[0029] The circuit board 3 has an acoustic channel 3A.

[0030] The vibration assembly 5 is disposed in the receiving space 100 and divides the receiving space 100 into a first conduction cavity 101 and a second conduction cavity 103 respectively connected to the acoustic channel 3A.

[0031] The vibration assembly 5 includes a vibration member 51 disposed opposite to and spaced from the circuit board 3, and a frame 53 connecting the vibration member 51 and the circuit board 3. The frame 53, the vibration member 51, the circuit board 3 and the housing 1 together form a first conduction cavity 101, and the frame 53, the vibration member 51 and the circuit board 3 together form a second conduction cavity 103.

[0032] The MEMS chip 7 is disposed in the second conducting cavity 103 and fixed to the circuit board 3 .

[0033] The MEMS chip 7 includes a substrate 71 having a back cavity 71A and a capacitor component 73 fixed on the substrate 71 and covering the back cavity 71A.

[0034] The capacitor assembly 73 includes a diaphragm 731 and a back plate 733 spaced apart from the diaphragm 731 . The diaphragm 731 is disposed between the circuit board 3 and the vibrating member 51 .

[0035] The vibration of the vibration member 51 is transmitted to one side of the diaphragm 731 via the first transmission cavity 101 and the acoustic channel 3A, and the vibration of the vibration member 51 is also transmitted to the other side of the diaphragm 731 via the second transmission cavity 103 . 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 vibration member 51 via the frame 53 so that the vibration member 51 vibrates in response to the vibration signal, and the vibration of the vibration member 51 causes the air pressure of the first conduction cavity 101 and the air pressure of the second conduction cavity 103 to change (specifically, when the air pressure in the first conduction cavity 101 increases, the air pressure in the second conduction cavity 103 decreases; when the air pressure in the first conduction cavity 101 decreases, the air pressure in the second conduction cavity 103 increases), so that the vibration of the vibration member 51 is transmitted to one side of the diaphragm 731 via the first conduction cavity 101 and the acoustic channel 3A, and the vibration of the vibration member 51 is also transmitted to the other side of the diaphragm 731 via the second conduction cavity 103. Therefore, the vibration of the vibration member 51 can act on the diaphragm 731 in a differential manner via two paths, thereby improving the vibration sensitivity of the diaphragm 731. The vibration of the diaphragm 731 will cause the capacitance of the capacitor assembly 73 to change, thereby converting the vibration signal transmitted through the bone into an electrical signal. The electrical signal picked up by the MEMS chip 7 is output via the circuit board 3.

[0036] It should be noted that, in order to allow the frame 53, the vibrating member 51, the circuit board 3 and the housing 1 to enclose the first conduction cavity 101 and the vibration of the vibrating member 51 to be conducted to one side of the diaphragm 731 through the first conduction cavity 101 and the acoustic channel 3A, the bottom wall 11 must be spaced apart from the vibrating member 51, and the side wall 13 must be spaced apart from the frame 53 at least partially. As shown in the figure, the side wall 13 is spaced apart from the frame 53 as a whole.

[0037] In this embodiment, preferably, the housing 1 has an electromagnetic shielding function. For example, the housing 1 with the electromagnetic shielding function can be made of conductive metal. In this way, the housing 1 can protect the internal structure of the bone conduction microphone while shielding the influence of external electromagnetic waves.

[0038] In this embodiment, the circuit board 3 includes an outer circuit board 31 that is connected to the housing 1 to form a receiving space 100 and an inner circuit board 33 that is fixed to the side of the outer circuit board 31 facing the receiving space 100, and the frame 53, the vibrating member 51, the outer circuit board 31 and the inner circuit board 33 are enclosed with the housing 1 to form a first conduction cavity 101, and the frame 53 is fixed to the side of the inner circuit board 33 that is away from the outer circuit board 31. The acoustic channel 3A includes an acoustic channel 3B that is connected to the first conduction cavity 101 and an acoustic hole 3C that is connected to the acoustic channel 3B. Among them, at least one direction of the outer circuit board 31 and the inner circuit board 33 is recessed to form the acoustic channel 3B, and the acoustic hole 3C runs through the inner circuit board 33.

[0039] It should be noted that at least one direction of the outer circuit board 31 and the inner circuit board 33 is recessed to form the sound channel 3B, including the following configurations:

[0040] The sound channel 3B is formed by the outer circuit board 31 being recessed in a direction away from the inner circuit board 33;

[0041] The sound channel 3B is formed by the inner circuit board 33 being recessed in a direction away from the outer circuit board 31;

[0042] A portion of the sound channel 3B is formed by the outer circuit board 31 being recessed in a direction away from the inner circuit board 33 , and another portion of the sound channel 3B is formed by the inner circuit board 33 being recessed in a direction away from the outer circuit board 31 .

[0043] like Figure 1 As shown, the sound channel 3B is formed by the outer circuit board 31 being recessed in a direction away from the inner circuit board 33 .

[0044] In this embodiment, the vibration element 51 includes a membrane 511 fixed to a frame 53 and a mass block 513 fixed to the membrane 511 .

[0045] like Figure 1 As shown, the mass block 513 is fixed to the side of the membrane body 511 facing the second conduction cavity 103. It is understandable that in other embodiments, the mass block 513 can also be fixed to the side of the membrane body 511 facing the first conduction cavity 101.

[0046] It should be noted that when the mass block 513 is fixed to the side of the membrane body 511 facing the second conduction cavity 103, in order to avoid the influence of the MEMS chip 7 on the vibration of the mass block 513, the mass block 513 and the MEMS chip 7 should have a sufficient distance; when the mass block 513 can also be fixed to the side of the membrane body 511 facing the first conduction cavity 101, in order to avoid the influence of the bottom wall 11 of the housing 1 on the vibration of the mass block 513, the mass block 513 and the bottom wall 11 should have a sufficient distance.

[0047] In order to further improve the sensitivity of the bone conduction microphone, in this embodiment, the bone conduction microphone further includes an ASIC chip 9 electrically connected to the MEMS chip 7, and the ASIC chip 9 is disposed in the second conduction cavity 103 and fixed on the inner circuit board 33 of the circuit board 3. Among them, the ASIC chip 9 provides an external bias for the MEMS chip 7, and an effective bias will enable the MEMS chip 7 to maintain stable acoustic sensitivity and electrical parameters within the entire operating temperature range, and can also support microphone structure designs with different sensitivities, making the design more flexible and reliable.

[0048] In this embodiment, the ASIC chip 9 and the MEMS chip 7 are electrically connected via a conductive wire 8 .

[0049] like Figure 1 As shown, the substrate 71 is directly fixed to the inner circuit board 33 of the circuit board 3, and the back cavity 71A is directly connected to the acoustic hole 3C of the acoustic channel 3A. It is understandable that in other embodiments, the substrate 71 can also be fixed to the inner circuit board 33 of the circuit board 3 through a gasket; or, the substrate 71 is fixed to the inner circuit board 33 of the circuit board 3 through a capacitor component 73, and the back cavity 71A is directly connected to the second conduction cavity 103.

[0050] Embodiment 2

[0051] See also Figure 3 The difference between the second embodiment and the first embodiment is that the outer circuit board 31 includes a first circuit board 311 connected to the inner circuit board 33 and the housing 1 respectively, and a second circuit board 313 fixed to the side of the first circuit board 311 away from the inner circuit board 33, and the first circuit board 311 is recessed to form the sound channel 3B.

[0052] As shown in the figure, the sound channel 3B is a hole structure that penetrates the first circuit board 311. It is understandable that in other embodiments, the sound channel 3B can also be configured as follows: a portion of the sound channel 3B is formed by the first circuit board 311 being recessed in a direction away from the inner circuit board 33, and another portion of the sound channel 3B is formed by the inner circuit board 33 being recessed in a direction away from the first circuit board 311.

[0053] Embodiment 3

[0054] See also Figure 4 The difference between the fourth embodiment and the second embodiment is only that:

[0055] The frame 53 includes a first frame 531 fixed on the inner circuit board 33 of the circuit board 3, a second frame 533 connected to the vibration member 51, and a partition 535 sandwiched between the first frame 531 and the second frame 533. The partition 535 separates the second conduction cavity 103 into a first cavity 105 and a second cavity 107. The partition 535 is provided with a through hole 537 connecting the first cavity 105 and the second cavity 107. The MEMS chip 7 and the ASIC chip 9 are arranged in the second cavity 107. In other words, the first frame 531, the partition 535 and the inner circuit board 33 of the circuit board 3 together enclose the first cavity 105, and the second frame 533, the partition 535 and the vibration member 51 together enclose the second cavity 107.

[0056] In this embodiment, the orthographic projection of the through hole 537 on the diaphragm 731 is located within the range of the diaphragm 731. This arrangement can further improve the vibration sensitivity of the diaphragm 731.

[0057] It should also be noted that, in the second embodiment, the first circuit board 311 and the inner circuit board 33 may also be configured as an integrally formed structure.

[0058] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present invention, but these all belong to the protection scope of the present invention.

Claims

1. A bone conduction microphone, characterized in that: It includes: shell; A circuit board is connected to the housing cover to form a receiving space, and the circuit board has an acoustic channel; a vibration assembly, arranged in the receiving space and dividing the receiving space into a first conduction cavity and a second conduction cavity respectively connected to the acoustic channel, the vibration assembly comprising a vibration member opposite to and spaced from the circuit board and a frame connecting the vibration member and the circuit board, the frame, the vibration member and the circuit board and the housing enclose the first conduction cavity, and the frame, the vibration member and the circuit board together enclose the second conduction cavity; A MEMS chip is arranged in the second conduction cavity and fixed to the circuit board, and the MEMS chip has a diaphragm arranged between the circuit board and the vibrating element, wherein the vibration of the vibrating element is transmitted to one side of the diaphragm via the first conduction cavity and the acoustic channel, and the vibration of the vibrating element is also transmitted to the other side of the diaphragm via the second conduction cavity.

2. The bone conduction microphone according to claim 1, characterized in that: The circuit board includes an outer circuit board connected to the outer shell to form the receiving space and an inner circuit board fixed to the outer circuit board on a side facing the receiving space, and the frame, the vibrating member, the outer circuit board and the inner circuit board are combined with the outer shell to form the first conduction cavity, the frame is fixed to a side of the inner circuit board away from the outer circuit board, the acoustic channel includes a sound channel connected to the first conduction cavity and a sound hole connected to the sound channel, wherein at least one direction of the outer circuit board and the inner circuit board is recessed to form the sound channel, and the sound hole passes through the inner circuit board.

3. The bone conduction microphone according to claim 2, characterized in that: The outer circuit board comprises a first circuit board connected to the inner circuit board and the outer shell respectively and a second circuit board fixed to a side of the first circuit board away from the inner circuit board, and the first circuit board is recessed to form the sound channel.

4. The bone conduction microphone according to claim 3, characterized in that: The sound channel passes through the first circuit board.

5. The bone conduction microphone according to claim 1, characterized in that: The vibration component includes a membrane body fixed to the frame and a mass block fixed to the membrane body.

6. The bone conduction microphone according to claim 5, characterized in that: The mass block is fixed to a side of the membrane body facing the first conduction cavity; or, the mass block is fixed to a side of the membrane body facing the second conduction cavity.

7. The bone conduction microphone according to any one of claims 1 to 6, characterized in that: The frame includes a first frame fixed to the circuit board, a second frame connected to the vibrating member, and a partition sandwiched between the first frame and the second frame, the partition divides the second conduction cavity into a first cavity and a second cavity, a through hole connecting the first cavity and the second cavity is penetrated on the partition, and the MEMS chip is arranged in the second cavity.

8. The bone conduction microphone according to claim 7, characterized in that: The orthographic projection of the through hole on the diaphragm is located within the range of the diaphragm.

9. 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 disposed in the second conduction cavity and fixed to the circuit board.

10. The bone conduction microphone according to claim 1, characterized in that: The MEMS chip includes a substrate with a back cavity and a capacitor component fixed on the substrate and covering the back cavity. The substrate is fixed on the circuit board, and the back cavity is connected to the acoustic channel. The capacitor component includes the diaphragm and a back plate spaced apart from the diaphragm.

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