WO2022000630A1

WO2022000630A1 - Vibration sensor and audio device having same

Info

Publication number: WO2022000630A1
Application number: PCT/CN2020/103775
Authority: WO
Inventors: 曾鹏; 李晋阳
Original assignee: 瑞声声学科技(深圳)有限公司
Priority date: 2020-06-30
Filing date: 2020-07-23
Publication date: 2022-01-06
Also published as: CN212572961U

Abstract

The present application provides a vibration sensor and an audio device having same. The vibration sensor comprises: a circuit board assembly, comprising a bottom wall and a side wall extending from the bottom wall; a housing covering the side wall and defining an accommodating cavity together with the circuit board assembly; a MEMS microphone disposed on the bottom wall of the circuit board assembly and located in the accommodating cavity, the MEMS microphone being electrically connected to the circuit board assembly; and a diaphragm assembly that is fixed between the housing and the side wall and divides the accommodating cavity into a first cavity and a second cavity, at least one first vent hole penetrating through the diaphragm assembly, and the first cavity communicates with the second cavity by means of the first vent hole. The housing is provided with at least one second vent hole penetrating through same. According to the vibration sensor, when a vibration signal or a pressure signal is inputted, the diaphragm assembly vibrates, and changes the air pressure in the accommodating cavity. The present application can effectively solve the problem in the prior art of insensitive response of a diaphragm of a vibration sensor.

Description

Vibration sensor and audio device having the same

technical field

The present application relates to the field of electro-acoustic conversion, and in particular, to a vibration sensor and an audio device having the same.

Background technique

With the development of technology, microphone equipment is developing from traditional air-conduction microphones to bone-conduction microphones. Usually, bone-conduction microphones sense the bone vibration of the user through the diaphragm, and then convert this vibration into electrical signals for recording or transmission. .

technical problem

The diaphragm of the bone conduction microphone of the prior art is arranged in the cavity of the vibration sensor, which is prone to the problem of insensitive induction, resulting in that the microphone cannot recognize or accurately recognize the user's voice. Therefore, it is necessary to provide a vibration sensor and an audio device having the same.

technical solutions

The purpose of the present application is to solve the problem of insensitive response of the diaphragm of the vibration sensor in the prior art.

The technical solution of the present application is as follows: in order to achieve the above purpose, the vibration sensor of the present application includes: a circuit board assembly, the circuit board assembly includes a bottom wall and a side wall extending from the bottom wall; The circuit board assembly is jointly formed into an accommodating cavity; the MEMS microphone is arranged on the bottom wall of the circuit board assembly and is located in the accommodating cavity, and the MEMS microphone is electrically connected with the circuit board assembly; the diaphragm assembly is fixed between the casing and the side wall and is The accommodating cavity is divided into a first cavity and a second cavity, at least one first vent hole is arranged through the diaphragm assembly, and the first cavity is communicated with the second cavity through the first vent hole; When the vibration sensor inputs a vibration signal or a pressure signal, the diaphragm assembly vibrates and changes the air pressure in the accommodating cavity.

Preferably, the diaphragm assembly includes a diaphragm body and a mass block, the diaphragm body is disposed in the accommodating cavity, the mass block is disposed on the diaphragm body, and the first vent hole is disposed on the diaphragm body.

Preferably, the mass block is arranged on the side of the diaphragm body close to the casing and/or the side of the diaphragm body away from the casing.

Preferably, the mass blocks located on the same side of the diaphragm body include a plurality of mass block units spaced apart from each other.

Preferably, the diaphragm assembly includes a diaphragm body and a mass block wrapped and fixed by the diaphragm body.

Preferably, a resonant cavity and a through hole communicating with the resonant cavity are provided on the bottom wall, and the MEMS microphone includes a base fixed on the bottom wall and having a back cavity, a MEMS diaphragm and a back plate supported on one end of the base away from the through hole ; The base surrounds the through hole and makes the back cavity communicate with the through hole; the MEMS diaphragm and the back plate are spaced to form a capacitance structure.

Preferably, the bottom wall includes a first layer and a second layer arranged at intervals and a support body arranged between the first layer and the second layer, a resonant cavity is formed between the first layer, the second layer and the support body, and the through hole is is disposed on the first layer, and the sidewall is disposed on the first layer.

Preferably, the vibration sensor further includes a spacer, and the spacer is arranged between the diaphragm assembly and the side wall.

Preferably, the vibration sensor further includes an ASIC chip, and the ASIC chip is disposed on the bottom wall and is electrically connected with the MEMS microphone.

On the other hand, the present application also provides an audio device including a vibration sensor, where the vibration sensor is a vibration sensor including all or part of the above technical features.

beneficial effect

The beneficial effect of the present application is that: the diaphragm assembly is arranged in the accommodating cavity formed by the casing and the circuit board assembly, and when the user makes a sound, the casing and the circuit board assembly sense the vibration of the user's sounding part to excite the diaphragm assembly to generate vibration . The first air release hole is arranged on the diaphragm assembly. When the diaphragm assembly vibrates, the gas in the accommodating cavity can flow between the first cavity and the second cavity on both sides of the diaphragm assembly through the first air release hole, so that the first cavity can flow. The air pressure of the first cavity and the second cavity on both sides of the diaphragm assembly is prevented from forming a closed space, resulting in the formation of high pressure or low pressure in the first cavity and the second cavity when the diaphragm assembly vibrates, which affects the diaphragm assembly. The vibration amplitude, thereby affecting the sensitivity of the vibration sensor. The circuit board assembly has a side wall and a bottom wall to form a half-pack structure, so that the diaphragm assembly can be directly fixed between the circuit board and the casing by being arranged on the side wall, thereby simplifying the fixing structure of the diaphragm assembly. The second vent hole enables the housing to smoothly discharge the excess gas in the first cavity and the second cavity when the housing is assembled to the circuit board assembly, so as to balance the air pressure in the accommodating cavity and the external air pressure of the vibration sensor.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of Embodiment 1 of the vibration sensor of the present application;

FIG. 2 shows a schematic diagram of an exploded structure of the vibration sensor of FIG. 1;

Fig. 3 shows the A-A sectional structural schematic diagram of the vibration sensor of Fig. 1;

4 is a schematic cross-sectional structural diagram of Embodiment 2 of the vibration sensor of the present application;

5 is a schematic cross-sectional structural diagram of Embodiment 3 of the vibration sensor of the present application;

6 is a schematic cross-sectional structural diagram of a fourth embodiment of the vibration sensor of the present application; and

FIG. 7 is a schematic cross-sectional structural diagram of Embodiment 5 of the vibration sensor of the present application.

The above figures contain the following reference numbers:

10. Housing; 11. Second vent hole; 20. Circuit board assembly; 21. Sidewall; 22. First layer; 23. Second layer; 24. Support body; 25. Through hole; 30. MEMS microphone; 31 , MEMS diaphragm; 32, base; 33, back plate; 34, back cavity; 40, diaphragm assembly; 41, diaphragm body; 411, sub diaphragm; 411, sub diaphragm; 42, first deflation hole; 43, mass; 50, gasket; 60, resonant cavity; 71, first cavity; 72, second cavity; 80, ASIC chip.

Embodiments of the present invention

In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the related drawings. The preferred embodiments of the present application are shown in the accompanying drawings. However, the application may be implemented in many other different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the disclosure of this application is provided.

It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and similar expressions are used herein for illustrative purposes only.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the specification of the application are for the purpose of describing specific embodiments only, and are not intended to limit the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Example 1:

As shown in FIGS. 1 to 3 , the vibration sensor of the first embodiment includes a housing 10 , a circuit board assembly 20 , a diaphragm assembly 40 and a MEMS (Microelectro Mechanical Systems, Micro-Electro-Mechanical Systems) microphone 30, the housing 10 is arranged on the circuit board assembly 20, an accommodation cavity 70 is arranged between the outer casing 10 and the circuit board assembly 20, the MEMS microphone 30 is arranged on the circuit board assembly 20 and is located in the accommodation In cavity 70 , MEMS microphone 30 is electrically connected to circuit board assembly 20 . The diaphragm assembly 40 is disposed in the accommodating cavity 70 , and at least one first vent hole 42 is disposed on the diaphragm assembly 40 .

Applying the technical solution of this embodiment, the diaphragm assembly 40 is arranged in the accommodating cavity 70 formed by the casing 10 and the circuit board assembly 20. When the user makes a sound, the casing 10 and the circuit board assembly 20 sense the vibration of the user's voice-producing part Thus, the diaphragm assembly 40 is excited to generate vibration. The first vent hole 42 is provided on the diaphragm assembly 40 . When the diaphragm assembly 40 vibrates, the gas in the accommodating cavity 70 can pass through the first vent hole 42 and the first cavity 71 and the second cavity on both sides of the diaphragm assembly 40 . 72, so that the air pressures of the first cavity 71 and the second cavity 72 are balanced, and the first cavity 71 and the second cavity 72 on both sides of the diaphragm assembly 40 are prevented from forming a closed space, causing the diaphragm assembly 40 to vibrate. The high pressure or low pressure formed in the first cavity 71 and the second cavity 72 affects the vibration amplitude of the diaphragm assembly 40, thereby affecting the sensitivity of the vibration sensor.

Because the performance of the MEMS microphone 30 is relatively stable under different temperature conditions, its sensitivity is basically not affected by factors such as temperature, vibration, temperature and time, and the reliability and stability are high. Because the MEMS microphone 30 can be subjected to high temperature reflow soldering at 260° C. and its performance is not affected, basic performance with high accuracy can still be achieved without the audio debugging process after assembly.

As shown in FIG. 2 and FIG. 3 , the diaphragm assembly 40 of this embodiment includes a diaphragm body 41 and a mass block 43 , the diaphragm body 41 is arranged in the accommodating cavity 70 , and the mass block 43 is arranged on the diaphragm body 41 away from the MEMS microphone On one side of 30 , the first vent hole 42 is provided on the diaphragm body 41 . The MEMS microphone 30 includes a base 32 and a MEMS diaphragm 31 disposed on the base 32 . The mass block 43 increases the inertia of the diaphragm assembly 40. When the user makes a sound, the sound vibration signal from the bone can vibrate the mass block 43, thereby driving the diaphragm body 41 to vibrate, and the vibrating diaphragm body 41 can push the accommodating cavity. The gas in the 70 vibrates and then vibrates the MEMS diaphragm 31 , thereby converting the vibration signal of the bone into an electrical signal to form the bone conduction MEMS microphone 30 .

In the vibration sensor of the above structure, when a vibration signal or a pressure signal is input to the side of the circuit board assembly 20 back to the accommodating cavity 70 and/or the side of the casing 10 away from the accommodating cavity 70, the diaphragm assembly 40 vibrates, specifically: The vibration of the mass block 43 drives the diaphragm body 41 to vibrate, causing the gas in the first cavity 71 to vibrate, thereby causing the MEMS diaphragm 31 of the MS microphone 30 accommodated in the first cavity 71 to vibrate, changing the relationship between the MEMS diaphragm 31 and the back. The distance between the polar plates 33 changes the capacitance generated by the MEMS microphone 30 , thereby realizing the conversion of the vibration signal into an electrical signal, that is, the synchronously changing electrical signal is transmitted to the circuit board assembly 20 , so that the MEMS microphone 30 will The external input vibration signal or pressure signal is converted into an electrical signal, and the vibration signal is converted into an electrical signal. For example, the circuit board assembly 20 of the vibration sensor is directly or indirectly attached to the neck of the user, and when the user makes a sound, the bone conduction transmits the vibration signal, so as to realize the above transformation process. In this process, the MEMS microphone 30 directly senses and detects the external input vibration signal, so that the MEMS microphone 30 can ensure the accurate detection of the change of gas vibration to the greatest extent, especially to the high-frequency vibration greater than 1KHz. The sensitivity and reliability of the vibration sensor.

It should be noted that, in other feasible embodiments, the mass block may also be disposed at other positions of the diaphragm body, or disposed on the diaphragm body in other forms.

Preferably, the orthographic projection area of the MEMS diaphragm 31 on the circuit board assembly 20 is smaller than the orthographic projection area of the diaphragm body 41 on the circuit board assembly 20 . This structure makes the contact area between the diaphragm body 41 and the gas in the accommodating cavity 70 larger, so that it can vibrate the gas better; the area of the MEMS diaphragm 31 is relatively small, so that the MEMS microphone 30 will cause the vibration caused by the speaker installed on the same PCB. The PCB noise produces lower vibration coupling, better acoustic performance, and ease of use.

As shown in FIG. 1 to FIG. 3 , at least one second vent hole 11 is provided on the casing 10 of this embodiment. When the whole machine SMT is assembled, the setting of the first pressure relief hole 11 plays the role of balancing the air pressure. Specifically, the accommodating cavity 70 communicates with the outside through the first vent hole 42 and the second vent hole 11 . When the housing 10 is assembled on the circuit board assembly 20 , excess gas can be discharged through the second vent hole 11 , thereby effectively avoiding During the assembly process, a high pressure is formed in the accommodating cavity 70, which further balances the air pressure outside the first cavity 71, the second cavity 72 and the vibration sensor.

After the assembly is completed, the housing 10 can be attached to the interior of the mobile device by surface assembly technology, and the second air vent 11 is blocked to seal the accommodating cavity 70, which effectively avoids the interference of the external air conduction sound signal, thereby improving the vibration sensor bone. Conductivity sensitivity and frequency characteristics. It can be understood that, in other feasible embodiments, the specific number and specific location of the second air vent holes 11 are not limited to the number and location shown in the figures, and can be adaptively adjusted as needed during specific implementation.

As shown in FIG. 2 and FIG. 3 , the circuit board assembly 20 of this embodiment includes a bottom wall and a side wall 21, the side wall 21 is arranged on the bottom wall, and the bottom wall and the side wall 21 form a hollow PCB support structure, so that the diaphragm The main body 41 can be directly arranged on the end face of the side wall 21, which plays the role of fixing the diaphragm body 41 and makes the mass block 43 hang in the accommodating cavity. The vibration sensor of this embodiment does not need to separately provide a fixing structure for fixing the diaphragm assembly 40 , which simplifies the fixing structure of the diaphragm assembly 40 and facilitates the fixing of the diaphragm body 41 .

As shown in FIG. 2 and FIG. 3 , the vibration sensor of this embodiment further includes a spacer 50 , and the spacer 50 is disposed between the diaphragm body 41 and the side wall 21 .

At the same time, the vibration component and the MEMS microphone 30 in this embodiment are arranged at intervals from each other, which avoids the integration of the vibration sensing device and the vibration detection device in the related art. Broadband is larger.

In order to improve the signal-to-noise ratio, as shown in FIGS. 2 and 3 , the bottom wall of this embodiment includes a first layer 22 and a second layer 23 arranged at intervals and a support arranged between the first layer 22 and the second layer 23 . The body 24 and the side walls 21 are provided on the first layer 22 . A resonant cavity 60 is formed between the first layer 22 , the second layer 23 and the support body 24 , and the first layer 22 is provided with a through hole 25 that communicates with the resonant cavity 60 . The MEMS microphone 30 is covered on the through hole 25 , and the resonant cavity 60 communicates with the back cavity 34 of the MEMS microphone 30 through the through hole 25 to form a larger back cavity 34 . The enlarged back cavity 34 of the MEMS microphone 30 enables the MEMS microphone 30 to better sense vibration signals, thereby effectively improving the signal-to-noise ratio.

More preferably, in order to further improve the sensitivity of the vibration sensor, as shown in FIG. 1 and FIG. 2 , the vibration sensor in this embodiment further includes an ASIC (Application Specific Integrated Circuit) chip 80 , the ASIC chip 80 is electrically connected to the MEMS microphone 30 . The ASIC chip 80 provides an external bias for the MEMS microphone 30. The effective bias will make the MEMS microphone 30 maintain stable acoustic and electrical parameters over the entire operating temperature range. It also supports the design of microphones with different sensitivities, making the design more flexible. reliable.

Embodiment 2:

The vibration sensor of the second embodiment adjusts the position of the mass block on the basis of the first embodiment. As shown in FIG. 4 , in the vibration sensor of the second embodiment, the mass block 43 is arranged on the diaphragm body 41 facing the MEMS microphone 30 . On the one hand, this embodiment reduces the space occupied by the mass 43 for the second cavity 72, and further improves the sensitivity of the vibration sensor. Other than that, it is basically the same as the above-mentioned embodiment shown in FIG. 2 , and details are not repeated here.

Embodiment three:

The vibration sensor of the third embodiment adjusts the setting method of the mass blocks on the basis of the first embodiment. Specifically, as shown in FIG. 5 , in the vibration sensor of the third embodiment, the mass blocks 43 are arranged on both sides of the diaphragm body 41 . That is, mass blocks 43 are provided on both the side of the diaphragm body 41 facing the MEMS microphone 30 and the side away from the MEMS microphone 30 . This embodiment increases the inertia of the diaphragm body 41 and further improves the sensitivity of the vibration sensor. Other than that, it is basically the same as the above-mentioned embodiment shown in FIG. 2 , and details are not repeated here.

Embodiment 4:

The vibration sensor of the fourth embodiment adjusts the setting method of the mass block on the basis of the third embodiment. Specifically, as shown in FIG. 6 , in the vibration sensor of the fourth embodiment, the mass block 43 is composed of a plurality of mass units arranged at intervals from each other. , this embodiment can not only increase the inertia of the diaphragm body 41 and further improve the sensitivity of the vibration sensor, but also increase the compliance of the diaphragm, making it easier to vibrate. Other than that, it is basically the same as the above-mentioned embodiment shown in FIG. 4 , and details are not repeated here.

Embodiment 5:

The vibration sensor of the fifth embodiment adjusts the setting method of the mass block on the basis of the first embodiment. Specifically, as shown in FIG. 7 , in the vibration sensor of the fifth embodiment, the diaphragm body 41 is composed of two layers of sub-diaphragms 411 stacked on each other. The mass block 43 is arranged between the two layers of sub-diaphragms 411 , and the first vent hole 42 is penetrated on the two layers of the sub-diaphragms 411 . This embodiment strengthens the fixing strength of the mass block 43 and improves the reliability of the vibration sensor. Other than that, it is basically the same as the above-mentioned embodiment shown in FIG. 3 , and details are not repeated here.

The present application also provides an audio device. The audio device (not shown in the figure) according to this embodiment includes a vibration sensor. Specifically, the vibration sensor is a vibration sensor including all or part of the above technical structures. The audio device of this embodiment has the advantage that the diaphragm is responsive.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

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

Claims

A vibration sensor, comprising:

a circuit board assembly including a bottom wall and side walls extending from the bottom wall;

a casing, the casing is covered on the side wall and forms an accommodating cavity together with the circuit board assembly;

a MEMS microphone, disposed on the bottom wall of the circuit board assembly and located in the accommodating cavity, the MEMS microphone being electrically connected to the circuit board assembly;

The diaphragm assembly is fixed between the casing and the side wall and divides the accommodating cavity into a first cavity and a second cavity, the diaphragm assembly is provided with at least one first vent hole therethrough, the The first cavity is communicated with the second cavity through the first vent hole;

The casing is provided with at least one second vent hole passing through it;

When a vibration signal or a pressure signal is input to the vibration sensor, the diaphragm assembly vibrates and changes the air pressure in the accommodating cavity.
The vibration sensor according to claim 1, wherein the diaphragm assembly comprises a diaphragm body and a mass block, the diaphragm body is arranged in the accommodating cavity, and the mass block is arranged on the diaphragm On the body, the first vent hole is arranged on the diaphragm body.
The vibration sensor according to claim 2, wherein the mass block is disposed on a side of the diaphragm body close to the casing and/or a side of the diaphragm body away from the casing.
The vibration sensor according to claim 3, wherein the mass blocks located on the same side of the diaphragm body comprise a plurality of mass block units spaced apart from each other.
The vibration sensor according to claim 1, wherein the diaphragm assembly comprises a diaphragm body and a mass block wrapped and fixed by the diaphragm body.
The vibration sensor according to claim 1, wherein a resonant cavity and a through hole communicating with the resonant cavity are provided on the bottom wall, and the MEMS microphone comprises a a base, a MEMS diaphragm and a back plate supported on one end of the base away from the through hole; the base surrounds the through hole and makes the back cavity communicate with the through hole; the MEMS vibration The membrane is spaced from the back plate to form a capacitor structure.
The vibration sensor according to claim 6, wherein the bottom wall comprises a first layer and a second layer arranged at intervals and a support body arranged between the first layer and the second layer, the The resonant cavity is formed between the first layer, the second layer and the support body, the through hole is arranged on the first layer, and the side wall is arranged on the first layer.
The vibration sensor according to claim 1, characterized in that, the vibration sensor further comprises a spacer, and the spacer is arranged between the diaphragm assembly and the side wall.
The vibration sensor according to claim 1, wherein the vibration sensor further comprises an ASIC chip, and the ASIC chip is disposed on the bottom wall and is electrically connected to the MEMS microphone.
An electronic device comprising a vibration sensor, wherein the vibration sensor is the vibration sensor according to any one of claims 1 to 9.