WO2020258174A1

WO2020258174A1 - Vibration sensor and audio device

Info

Publication number: WO2020258174A1
Application number: PCT/CN2019/093338
Authority: WO
Inventors: 张金宇
Original assignee: 瑞声声学科技(深圳)有限公司
Priority date: 2019-06-27
Filing date: 2019-06-27
Publication date: 2020-12-30
Also published as: CN210093551U

Abstract

The present application provides a vibration sensor and an audio device. The vibration sensor comprises a cavity having a sidewall, an elastic film mounted on the sidewall, and an MEMS chip having a back cavity. The MEMS chip is received within the cavity and mounted on the elastic film. The sidewall comprises a side surface attached to the elastic film. The side surface recesses toward a direction away from the MEMS chip to form a recessed cavity. The elastic film covers the recessed cavity and is provided with a through hole. The through hole makes the recessed cavity and the back cavity of the MEMS chip be communicated with each other. The vibration sensor of the present application features a small height and high sensibility.

Description

Vibration sensor and audio equipment

Technical field

The utility model relates to the field of microphones, in particular to a vibration sensor and audio equipment.

Background technique

The prior art vibration sensor generally includes a housing having a front cavity and an opening communicating with the front cavity, an elastic membrane covering the opening and having a through hole communicating with the front cavity, a mass mounted on the side of the elastic membrane facing away from the front cavity, and a device. The MEMS chip used to receive the vibration signal in the front cavity. When the external vibration signal is transmitted to the vibration sensor through the structure, the mass vibrates up and down, causing the volume of the front cavity to change, and the gas pressure in the front cavity changes accordingly. The signal is picked up by the MEMS core and converted into an electrical signal. However, the prior art vibration sensor has the problem of complex structure and low sensitivity.

Therefore, it is necessary to provide a vibration sensor with a simple structure and high sensitivity.

technical problem

The purpose of the utility model is to provide a vibration sensor with high sensitivity.

Technical solutions

The technical scheme of the utility model is as follows:

A vibration sensor is provided, which includes a cavity with side walls, an elastic membrane mounted on the side walls, and a MEMS chip with a back cavity. The MEMS chip is accommodated in the cavity and mounted on the elastic membrane. The side wall includes a side surface attached to the elastic film, the side surface is recessed in a direction away from the MEMS chip to form a cavity, the elastic film covers the cavity and the elastic film is provided with a through hole, the The through hole communicates with the cavity and the back cavity of the MEMS chip.

Further, the cross-sectional area of the cavity along the vibration direction of the elastic membrane is larger than the cross-sectional area of the back cavity along the vibration direction of the elastic membrane.

Further, the cavity includes a circuit board and a shell fixed on the circuit board, and the elastic film is mounted on the circuit board.

Further, the elastic film is adhesively connected to the circuit board.

Further, the MEMS chip is adhesively connected to the elastic membrane.

Further, the vibration sensor further includes an ASIC chip housed in the cavity, and the ASIC chip is electrically connected to the MEMS chip and the circuit board.

Further, the ASIC chip is adhesively connected to the circuit board.

Further, a sound hole is opened on the shell.

An audio device is also provided, including the vibration sensor described above.

Beneficial effect

The beneficial effect of the utility model is that the MENS chip is arranged on the elastic membrane. When the external vibration signal is transmitted to the vibration sensor through the structure, the MEMS chip vibrates up and down, causing the volume of the front cavity to change, and the gas pressure in the front cavity changes accordingly. The pressure signal is picked up by the MEMS chip and converted into an electrical signal, making the changed pressure signal easier to be picked up by the MEMS chip, which improves the sensitivity of the vibration sensor and reduces the height of the product.

Description of the drawings

Figure 1 is a schematic structural view of a vibration sensor provided by an embodiment of the utility model;

Figure 2 is an exploded view of the vibration sensor in Figure 1;

Fig. 3 is a schematic cross-sectional view along line A-A of Fig. 1.

In the picture:

100. Vibration sensor; 1. Cavity; 101, side; 102, cavity; 11. Circuit board; 2. Elastic membrane; 3. MEMS chip; 12, housing; 20, through hole; 30, back cavity; 4. ASIC chip; 120, sound hole.

Embodiments of the invention

The present utility model will be further explained below in conjunction with the drawings and the embodiments.

1, the present invention provides a vibration sensor 100, which includes a cavity with a side wall 1, an elastic membrane 2 mounted on the side wall, and a MEMS chip 3 with a back cavity. The MEMS chip 3 is accommodated in The MEMS chip 3 in the cavity 1 and mounted on the elastic membrane 2 and capable of vibrating with the elastic membrane 2. The sidewall includes a side surface 101 attached to the elastic membrane 2, and the side surface 101 A cavity 102 is recessed away from the MEMS chip 3, the elastic membrane 2 covers the cavity 102, and the elastic membrane 2 is provided with a through hole 20, and the through hole 20 communicates with the cavity 102 And the back cavity 30 of the MEMS chip 3.

The MEMS chip 3 is mounted on the upper side of the elastic membrane 2. When the external vibration signal is transmitted to the vibration sensor 100 through the structure, the MEMS chip 3 vibrates up and down with the elastic membrane 2, causing the volume of the cavity 102 to change. The medium in the cavity 102 is like a gas. The pressure changes accordingly, and the changed pressure signal is picked up by the MEMS chip 3.

Preferably, the cross-sectional area of the cavity 102 along the vibration direction of the elastic membrane 2 is larger than the cross-sectional area of the back cavity 30 along the vibration direction of the elastic membrane 2.

Preferably, the cavity 1 includes a circuit board 11 and a housing 12 fixed on the circuit board 11, and the elastic membrane 2 is mounted on the circuit board 11. The cavity 102 is formed on the inner surface of the circuit board 11. Understandably, the sidewalls forming the cavity 102 and the circuit board 11 may also be separately provided.

Preferably, the elastic film 2 and the circuit board 11 are adhesively connected.

Preferably, the MEMS chip 3 and the elastic membrane 2 are adhesively connected.

Preferably, the vibration sensor 100 further includes an ASIC chip 4 housed in the cavity 1, and the ASIC chip 4 is electrically connected to the MEMS chip 3 and the circuit board 11. The ASIC chip 4 is used to process the vibration signal picked up by the MEMS chip 4.

Preferably, the ASIC chip 4 and the circuit board 11 are adhesively connected.

Preferably, a sound hole 120 is opened on the housing 12. The sound hole 120 is used to allow sound to enter the cavity, so that the MEMS chip 3 can pick up vibration signals and sound signals at the same time. Preferably, the sound hole 120 is opened on the side wall of the housing 12 opposite to the circuit board 11. In this way, the sound hole 120 is opposite to the MEMS chip 3, which facilitates the MEMS chip 3 to receive sound signals.

The present invention also provides an audio device (not shown in the figure), including the vibration sensor 100 as described above.

In the vibration sensor 100 provided by the present utility model, when the external vibration signal is transmitted to the vibration sensor 100 through the structure, the MEMS chip 3 vibrates up and down with the elastic membrane 2, causing the volume of the cavity 102 to change, and the pressure of the medium such as gas in the cavity 102 When the change occurs, the changed pressure signal is picked up by the MEMS chip 3, and the MEMS chip 3 functions as a mass block, the height of the vibration sensor 100 is reduced, and the sensitivity is increased.

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 scope of protection of the utility model.

To

Claims

A vibration sensor, characterized by comprising a cavity with a side wall, an elastic membrane mounted on the side wall, and a MEMS chip with a back cavity, the MEMS chip being housed in the cavity and mounted on the elastic membrane , The side wall includes a side surface attached to the elastic film, the side surface is recessed in a direction away from the MEMS chip to form a cavity, the elastic film covers the cavity and the elastic film is provided with a through hole The through hole communicates with the cavity and the back cavity of the MEMS chip.
The vibration sensor according to claim 1, wherein the cross-sectional area of the cavity along the vibration direction of the elastic membrane is larger than the cross-sectional area of the back cavity along the vibration direction of the elastic membrane.
The vibration sensor according to claim 1, wherein the cavity includes a circuit board and a housing fixed on the circuit board, and the elastic membrane is mounted on the circuit board.
The vibration sensor according to claim 3, wherein the elastic membrane is adhesively connected to the circuit board.
The vibration sensor according to claim 3, wherein the MEMS chip is adhesively connected to the elastic membrane.
3. The vibration sensor according to claim 3, wherein the vibration sensor further comprises an ASIC chip housed in the cavity, and the ASIC chip is electrically connected to the MEMS chip and the circuit board.
The vibration sensor according to claim 6, wherein the ASIC chip is adhesively connected to the circuit board.
The vibration sensor according to claim 3, wherein the housing is provided with a sound hole.
An audio device, characterized by comprising the vibration sensor according to any one of claims 1-8.