WO2021134202A1

WO2021134202A1 - Bone conduction microphone

Info

Publication number: WO2021134202A1
Application number: PCT/CN2019/129898
Authority: WO
Inventors: 张金宇; 王凯
Original assignee: 瑞声声学科技(深圳)有限公司
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2021-07-08

Abstract

Provided in the present utility model is a bone conduction microphone, comprising: a housing provided with a receiving cavity and an acoustoelectric conversion component contained in the receiving cavity; the housing comprises a lower cover plate and an upper cover plate that forms the receiving cavity together with the lower cover plate; the acoustoelectric conversion component comprises a spring piece clamped between the upper cover plate and the lower cover plate, a first mass piece disposed on the spring piece so as to face the lower cover plate, and a second mass piece provided on the spring piece so as to face the upper cover plate; the lower cover plate is provided with a first electrode plate disposed opposite to the first mass piece, the upper cover plate is provided with a second electrode plate disposed opposite to the second mass piece, and the first mass piece and the second mass piece are coated by an electret layer; the first mass piece forms a first capacitor with the first electrode plate, and the second mass piece forms a second capacitor with the second electrode plate. The bone conduction microphone also comprises an integrated circuit chip electrically connected to the first capacitor and the second capacitor. By using the present technical solution, the structure is simple, while sensitivity can also be doubled by using the differential principle so as to improve anti-interference performance.

Description

Bone conduction microphone

Technical field

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

Background technique

Bone conduction microphones are different from condenser microphones. Bone conduction microphones pick up vibration signals. When speaking, the vibration of the vocal cords is transmitted to the external auditory canal or nasal bone through the skull, and a bone conduction microphone is attached to the surface of the skin at this location to detect the vibration signal of the person speaking. Moreover, through a certain design, the volume of the bone conduction microphone can be reduced to a certain range. In practical applications, the bone conduction microphone can be integrated into the wearable electronic device, and the position of the wearable electronic device with the microphone can be attached to the wearable electronic device. The skin near the external auditory canal or the nasal bone can cooperate with wearable electronic devices to realize voice communication. Even in a strong noisy environment, the bone conduction microphone can ensure the quality of the call. However, the bone conduction microphone in the prior art consists of a pressure generator and a MEMS (Micro Electro Mechanical System) microphone. The bone conduction microphone using this design method needs to include a signal processor and multiple cavities, and its structure is complicated. , The production cost is high, and the sensitivity is low.

Therefore, it is necessary to provide a bone conduction microphone.

technical problem

The purpose of the utility model is to provide a bone conduction microphone, which has a simple structure and can use the differential principle to improve the microphone sensitivity.

Technical solutions

The technical scheme of the utility model is as follows:

A bone conduction microphone includes: a housing that induces vibration and has a receiving cavity and an acoustic-electric conversion component received in the receiving cavity. The housing includes a lower cover plate and the lower cover plate forming the The upper cover plate of the receiving cavity; the sound-electric conversion assembly includes an elastic sheet clamped between the upper cover plate and the lower cover plate, and a first mass arranged on the side of the elastic sheet facing the lower cover plate Plate and a second mass plate arranged on the side of the elastic plate facing the upper cover plate; the lower cover plate is provided with a first electrode plate arranged opposite to the first mass plate, and the upper cover plate A second electrode plate is provided opposite to the second mass sheet, the first mass sheet and the second mass sheet are coated with an electret layer; the first mass sheet and the first electrode The space between the plates forms a first capacitor, the second mass sheet and the second electrode plate are spaced to form a second capacitor. The bone conduction microphone further includes a bone conduction microphone fixed to the housing and connected to the first capacitor and the first capacitor. The second capacitor is electrically connected to the integrated circuit chip.

Further, the orthographic projection of the second mass sheet along the vibration direction of the casing coincides with the orthographic projection of the first mass sheet along the vibration direction of the casing.

Further, the lower cover plate includes a first bottom plate and a first ring-shaped frame body sandwiched between the first bottom plate and the elastic sheet.

Further, the first bottom plate extends toward the elastic sheet to form the first electrode plate.

Further, the upper cover plate includes the second electrode plate and a second ring-shaped frame body sandwiched between the second electrode plate and the elastic sheet.

Further, the elastic piece includes a main body part sandwiched between the first annular frame body and the second annular frame body, a holding part arranged spaced apart from the main body part, and a holding part extending from the main body part to the For the elastic arm of the holding portion, the first mass piece and the second mass piece are respectively fixed on opposite sides of the holding portion.

Further, the integrated circuit chip is fixed to the lower cover plate and electrically connected with the lower cover plate and the elastic sheet.

Further, the shrapnel is provided with a avoidance gap corresponding to the integrated circuit chip, and the integrated circuit chip is electrically connected to the shrapnel through the avoidance gap.

Beneficial effect

The beneficial effect of the utility model is that: in the technical scheme, the first mass plate coated with the electret layer and the first electrode plate are spaced apart to form a first capacitor, and the second mass plate coated with the electret layer Spaced from the second electrode plate to form a second capacitor, the integrated circuit chip is electrically connected to the first capacitor and the second capacitor; when the upper cover and the lower cover receive the vibration signal from the outside, the elastic sheet is clamped on the upper cover Between the plate and the lower cover plate, the vibration signal is transmitted to the elastic plate, and the first mass plate and the second mass plate arranged on the elastic plate move relative to the whole shell due to the effect of inertia. The relative distance between one electrode plate and the relative distance between the second mass sheet and the second electrode plate change, which in turn causes the capacitance value of the first capacitor and the capacitance value of the second capacitor to change inversely, resulting in a reverse difference Electrical signals, differential electrical signals are picked up by integrated circuit chips. By using this technical solution, not only the structure is simple, but also the sensitivity can be doubled by using the differential principle, the anti-interference performance is improved, and the total harmonic distortion is reduced.

Description of the drawings

Figure 1 is a schematic structural diagram of a bone conduction microphone in an embodiment of the utility model;

Fig. 2 is a schematic diagram of an exploded structure of Fig. 1;

Figure 3 is a schematic diagram of the structure of the shrapnel;

Figure 4 is a cross-sectional view in the direction of A-A in Figure 1;

Fig. 5 is a partial enlarged schematic diagram of B in Fig. 4.

Embodiments of the present invention

It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other if there is no conflict. Hereinafter, the present utility model will be described in detail with reference to the drawings and the embodiments.

It should be pointed out that the following detailed descriptions are all illustrative and are intended to provide further explanations for the application. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

It should be noted that the terms used here are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and/or "including" are used in this specification, they indicate There are features, steps, operations, devices, components, and/or combinations thereof.

The present utility model will be further explained below in conjunction with the drawings and embodiments. Referring to Figures 1-2, a bone conduction microphone includes a housing 10 that senses vibration and has a receiving cavity and an acoustic-electric conversion assembly 20 accommodated in the receiving cavity. The housing 10 includes a lower cover 11 and a lower cover The plate 11 forms the upper cover 12 of the accommodating cavity; the acoustic-electric conversion assembly 20 includes an elastic sheet 21 clamped between the upper cover 12 and the lower cover 11, and a first mass arranged on the side of the elastic sheet 21 facing the lower cover 11 The sheet 22 and the second mass sheet 23 arranged on the side of the elastic sheet 21 facing the upper cover plate 12; the lower cover plate 11 is provided with a first electrode plate 11a arranged opposite to the first mass sheet 22, and the upper cover plate 12 is provided with The second electrode plate 121 is arranged opposite to the second mass sheet 23. The first mass sheet 22 and the second mass sheet 23 are coated with an electret layer; the first mass sheet 22 is spaced from the first electrode plate 11a to form a first A capacitor. The second mass sheet 23 is spaced from the second electrode plate 121 to form a second capacitor. The bone conduction microphone further includes an integrated circuit chip 30 fixed to the housing 10 and electrically connected to the first capacitor and the second capacitor.

In this technical solution, the first mass sheet 22 coated with an electret layer and the first electrode plate 11a are spaced apart to form a first capacitor, and the second mass sheet 23 coated with an electret layer and the second electrode plate 11a are spaced apart to form a first capacitor. 121 are arranged at intervals to form a second capacitor. The integrated circuit chip 30 is electrically connected to the first capacitor and the second capacitor. When the upper cover plate 12 and the lower cover plate 11 receive vibration signals from the outside, the elastic sheet 21 is clamped on the upper cover Between the plate 12 and the lower cover plate 11, the vibration signal is transmitted to the elastic sheet 21; and the first mass sheet 22 and the second mass sheet 23 disposed on the elastic sheet 21 move relative to the entire housing 10 due to inertia. , The relative distance between the first mass sheet 22 and the first electrode plate 11a, and the relative distance between the second mass sheet 23 and the second electrode plate 121 change, thereby making the capacitance of the first capacitor and the capacitance of the second capacitor change The capacitance changes reversely to produce a reverse differential electrical signal, and the differential electrical signal is picked up by the integrated circuit chip. By using this technical solution, not only the structure is simple, but also the sensitivity can be doubled by using the differential principle, the anti-interference performance is improved, and the total harmonic distortion is reduced.

Preferably, the orthographic projection of the second mass sheet 23 along the vibration direction of the casing 10 coincides with the orthographic projection of the first mass sheet 22 along the vibration direction of the casing 10. 4 and 5, the positions and sizes of the first quality piece 22 and the second quality piece 23 are set so that the first quality piece 22 and the second quality piece 23 are arranged directly opposite each other, and the first quality piece 22 The size and specifications of the second mass plate 23 are the same. Therefore, the capacitance difference between the first capacitor and the second capacitor depends on the distance change caused by the vibration amplitude of the shrapnel 21, and the vibration amplitude of the shrapnel 21 depends on the external vibration signal, thereby effectively improving The sensitivity of the bone conduction microphone.

Furthermore, the lower cover 11 includes a first bottom plate 111 and a first ring frame 112 sandwiched between the first bottom plate 111 and the elastic sheet 21. The lower cover plate 11 is decomposed into a first bottom plate 111 and a first ring-shaped frame 112. When the housing 10 is vibrated, the vibration signal can be effectively transmitted to the elastic sheet 21.

Preferably, the first bottom plate 111 extends toward the elastic sheet 21 to form a first electrode plate 11a. The first electrode plate 11a and the first mass sheet 22 form a first capacitor. When the elastic sheet 21 vibrates toward the first bottom plate 111, the first electrode plate 11a can be increased. The difference between a capacitor and a second capacitor.

Furthermore, the upper cover plate 12 includes a second electrode plate 121 and a second annular frame 122 sandwiched between the second electrode plate 121 and the elastic sheet 21. The second electrode plate 121 and the second mass sheet 23 form a second capacitor. The second ring frame body 122 is used to hold the elastic sheet 21. The first ring frame body 112 and the second ring frame body 122 are used to hold the elastic sheet 21 on the one hand, and the other On the one hand, it provides movement space for the first mass piece 22 and the second mass piece 23, and on the other hand, the external vibration signal is effectively and directly transmitted to the elastic piece 21.

3, the elastic sheet 21 includes a main body portion 211 sandwiched between the first ring frame 112 and the second ring frame 122, a holding portion 212 spaced apart from the main body portion 211, and a holding portion 212 extending from the main portion 211 to the holding portion 212. The elastic arm 213, the first mass piece 22 and the second mass piece 23 are respectively fixed on opposite sides of the holding portion 212. The main body 211 is used to hold the elastic sheet 21 between the first frame 112 and the second frame 122 to receive the vibration signal; the first mass sheet 22 and the second mass sheet 23 are respectively fixed on opposite sides of the holding portion 212 Therefore, the first mass piece 22 and the second mass piece 23 can move relative to the entire housing 10 through the retaining portion 212, and then the main body portion 211 and the retaining portion 212 are connected through the elastic arm 213, which can increase the elastic movement range of the retaining portion 212 Therefore, the first mass piece 22 and the second mass piece 23 can move relatively to the housing 10 in a relatively large range, and the sensitivity of the microphone is greatly improved based on the principle of difference.

Further, the integrated circuit chip 30 is fixed to the lower cover 11 and is electrically connected to the lower cover 11 and the elastic sheet 21. The lower cover 11 and the elastic sheet 21 are made of metal materials to be electrically connected to the integrated circuit chip 30, thereby achieving integration The electrical signal of the circuit chip 30 is picked up.

As shown in FIG. 3, the shrapnel 21 is provided with an avoidance gap 21a corresponding to the integrated circuit chip 30, and the integrated circuit chip 30 is electrically connected to the shrapnel 21 through the avoidance gap 21a.

The above are only the embodiments of the present utility model. It should be pointed out here 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 all belong to the present utility model. New scope of protection.

Claims

A bone conduction microphone includes a shell that senses vibration and has a receiving cavity and an acoustic-electric conversion component accommodated in the receiving cavity. The shell is characterized in that the shell includes a lower cover plate and a lower cover plate. An upper cover plate forming the receiving cavity; the acoustic-electric conversion assembly includes an elastic sheet clamped between the upper cover plate and the lower cover plate, and a side of the elastic sheet facing the lower cover plate A first mass piece and a second mass piece arranged on the side of the elastic piece facing the upper cover plate; the lower cover plate is provided with a first electrode plate arranged opposite to the first mass piece, and the upper The cover plate is provided with a second electrode plate arranged opposite to the second mass sheet, the first mass sheet and the second mass sheet are coated with an electret layer; the first mass sheet and the The first electrode plate is spaced to form a first capacitor, and the second mass sheet is spaced from the second electrode plate to form a second capacitor. The bone conduction microphone further includes fixed to the housing and connected to the first capacitor. And an integrated circuit chip electrically connected to the second capacitor.
The bone conduction microphone according to claim 1, wherein the orthographic projection of the second mass plate along the vibration direction of the housing coincides with the orthographic projection of the first mass plate along the vibration direction of the housing. .
The bone conduction microphone according to claim 2, wherein the lower cover plate comprises a first bottom plate and a first ring-shaped frame body sandwiched between the first bottom plate and the elastic sheet.
The bone conduction microphone according to claim 3, wherein the first bottom plate extends toward the elastic sheet to form the first electrode plate.
The bone conduction microphone according to claim 4, wherein the upper cover plate comprises the second electrode plate and a second ring-shaped frame body sandwiched between the second electrode plate and the elastic sheet .
The bone conduction microphone according to claim 5, wherein the elastic sheet comprises a main body part sandwiched between the first ring frame body and the second ring frame body, and is spaced from the main body part. A retaining portion and an elastic arm extending from the main body portion to the retaining portion are provided, and the first mass piece and the second mass piece are respectively fixed on opposite sides of the retaining portion.
The bone conduction microphone according to claim 1, wherein the integrated circuit chip is fixed to the lower cover plate and is electrically connected to the lower cover plate and the elastic sheet.
8. The bone conduction microphone according to claim 7, wherein the shrapnel is provided with a avoidance gap corresponding to the integrated circuit chip, and the integrated circuit chip is electrically connected to the shrapnel through the avoidance gap.