CN218679383U

CN218679383U - Vibration sensor

Info

Publication number: CN218679383U
Application number: CN202021264706.6U
Authority: CN
Inventors: 曾鹏; 胡恒宾
Original assignee: AAC Acoustic Technologies Shenzhen Co Ltd
Current assignee: AAC Technologies Holdings Shenzhen Co Ltd
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2023-03-21
Anticipated expiration: 2030-06-30
Also published as: WO2022000853A1

Abstract

The utility model provides a vibration sensor, which comprises a circuit board, wherein the circuit board is provided with an accommodating cavity and a through hole; the shell cover is fixed on the circuit board and covers the through hole, the shell and the circuit board enclose a resonant cavity, and the shell is provided with a first pressure relief hole; the MEMS microphone is accommodated in the accommodating cavity and is electrically connected with the circuit board, and the MEMS microphone comprises a base, a first vibrating diaphragm and a back plate, wherein the base is fixed on the circuit board and is provided with a back cavity; the base surrounds the through hole to enable the back cavity to be communicated with the through hole; the first vibrating diaphragm and the back plate are spaced to form a capacitor structure; the vibrating diaphragm component divides the resonant cavity into a first cavity and a second cavity, and the first cavity is communicated with the back cavity through a through hole; the vibrating diaphragm assembly is provided with a second pressure relief hole, and the first cavity is communicated with the second cavity through the second pressure relief hole; when the vibration sensor inputs a vibration signal or a pressure signal, the vibrating diaphragm component vibrates and changes the air pressure in the resonant cavity. Compared with the prior art, the utility model discloses a vibration sensor sensitivity is higher, and the reliability is better.

Description

Vibration sensor

[ technical field ] A method for producing a semiconductor device

The utility model relates to an acoustoelectric conversion field especially relates to a vibration sensor for bone conduction electronic product.

[ background of the invention ]

And the vibration sensor is used for converting the vibration signal into an electric signal. At present, the existing MEMS vibration sensor comprises a vibrating diaphragm component serving as a vibration sensing device and an MEMS microphone serving as a vibration detection device for converting a vibration signal into an electric signal, wherein the vibration sensing device and the vibration detection device are integrated together, and the MEMS microphone can sense under the condition of direct extrusion contact under pressure due to piezoelectric or capacitive sensing, so that the MEMS vibration sensor is sensitive to low-frequency vibration smaller than 500Hz, but poor in response to high-frequency vibration larger than 1KHz, and poor in performance in the field of audio equipment.

Therefore, there is a need to provide a new vibration sensor to solve the above technical problems.

[ Utility model ] content

An object of the utility model is to provide a vibration sensor that sensitivity is high, good reliability.

In order to achieve the above object, the present invention provides a vibration sensor, which includes:

the circuit board is enclosed into an accommodating cavity, and a through hole penetrating through the circuit board is formed in one side of the circuit board;

the shell is covered and fixed on the circuit board and covers the through hole, the shell and the circuit board jointly enclose a resonant cavity, and the shell is provided with a first pressure relief hole penetrating through the shell;

the MEMS microphone is accommodated in the accommodating cavity and is electrically connected with the circuit board, and the MEMS microphone comprises a base which is fixed on the circuit board and is provided with a back cavity, a first vibrating diaphragm and a back plate which are supported at one end of the base, which is far away from the through hole; the base surrounds the through hole and enables the back cavity to be communicated with the through hole; the first vibrating diaphragm and the back plate form a capacitor structure at intervals; and the number of the first and second groups,

the vibrating diaphragm assembly is accommodated in the resonant cavity and divides the resonant cavity into a first cavity and a second cavity, and the first cavity is communicated with the back cavity through the through hole; the diaphragm assembly is provided with a second pressure relief hole penetrating through the diaphragm assembly, and the first cavity is communicated with the second cavity through the second pressure relief hole;

when the vibration sensor inputs a vibration signal or a pressure signal, the vibrating diaphragm component vibrates and changes the air pressure in the resonant cavity.

Preferably, the vibration sensor further comprises an ASIC chip, and the ASIC chip is accommodated in the accommodating cavity and electrically connected with the MEMS microphone.

Preferably, the circuit board includes a bottom plate and a surrounding wall extending from the bottom plate to a direction close to the housing and surrounding the housing into the receiving cavity, and the housing is fixed to the bottom plate and spaced from the surrounding wall.

Preferably, the housing includes a housing plate opposite to the circuit board at an interval and a side plate bent and extended from the periphery of the housing plate to the circuit board and fixed to the circuit board, and the first pressure relief hole penetrates through the housing plate.

Preferably, the vibrating diaphragm assembly comprises a gasket fixed on the circuit board and surrounding the through hole and a second vibrating diaphragm fixed on one side of the gasket far away from the through hole, the gasket, the second vibrating diaphragm and the circuit board jointly enclose the first cavity, and the second pressure relief hole penetrates through the second vibrating diaphragm.

Preferably, the diaphragm assembly further comprises a mass block fixedly connected with the second diaphragm; the mass block is attached to one side of the second diaphragm close to the first cavity and/or one side of the second diaphragm close to the second cavity.

Preferably, the mass located on the same side of the second diaphragm includes a plurality of mass units spaced from each other.

Preferably, the diaphragm assembly further includes a mass wrapped and fixed by the second diaphragm.

Preferably, the second diaphragm comprises two second sub-diaphragms fixed to the gasket and stacked with each other, and the mass block is clamped between the two second sub-diaphragms.

Preferably, the area of the forward projection of the first diaphragm on the circuit board along the vibration direction of the first diaphragm is smaller than the area of the forward projection of the second diaphragm on the circuit board along the vibration direction of the second diaphragm.

Compared with the prior art, the vibration sensor of the utility model has the advantages that the circuit board is enclosed into an accommodating cavity, one side of the circuit board is provided with the through hole, and the accommodating cavity is internally provided with the MEMS microphone; the shell and the circuit board are arranged to jointly enclose a resonant cavity, the shell is provided with a first pressure relief hole penetrating through the shell, a vibrating diaphragm assembly is arranged in the resonant cavity to divide the resonant cavity into a first cavity and a second cavity, and the first cavity is communicated with the back cavity through a through hole; the diaphragm assembly is provided with a second pressure relief hole penetrating through the diaphragm assembly, and the first cavity is communicated with the second cavity through the second pressure relief hole; the MEMS microphone comprises a base, a first diaphragm and a back plate, wherein the base is fixed on the circuit board and provided with a back cavity; the base surrounds the through hole and enables the back cavity to be communicated with the through hole; the through hole communicates the first cavity with the back cavity. Through the structural design, the vibrating diaphragm assembly is accommodated in a resonant cavity formed by the shell and the circuit board, the shielding effect is better, and meanwhile, the volume of the cavity for generating air pressure change is increased, and the vibration effect is better; the MEMS microphone can better sense the vibration generated by the vibrating diaphragm component and convert the sensed vibration signal into an electric signal, so that the high-frequency vibration and the low-frequency vibration transmitted by the resonant cavity have better vibration response, and the sensitivity is effectively improved.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained without inventive work, wherein:

fig. 1 is a schematic structural diagram of the vibration sensor of the present invention;

fig. 2 is an exploded view of the vibration sensor of the present invention;

FIG. 3 isbase:Sub>A cross-sectional view taken along A-A of FIG. 1;

fig. 4 is a schematic structural diagram of a second embodiment of a fixing manner of a mass block and a second diaphragm of the vibration sensor in fig. 1;

fig. 5 is a schematic structural diagram of a third embodiment of a fixing manner of a mass and a second diaphragm of the vibration sensor in fig. 1;

FIG. 6 is a schematic structural diagram of another embodiment of the mass block of FIG. 5 after structural modification;

fig. 7 is a schematic structural view of a fourth embodiment of the fixing mode of the mass block and the diaphragm in the vibration sensor of the present invention.

[ detailed description ] embodiments

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that the technical solutions in the embodiments can be combined with each other, but must be based on the realization of those skilled in the art.

Referring to fig. 1-3, the present invention provides a vibration sensor 100, which includes a circuit board 1, a housing 2, a MEMS microphone 3 and a diaphragm assembly 4.

The circuit board 1 encloses to form an accommodating cavity 10, and one side of the circuit board 1 is provided with a through hole 11 penetrating through the circuit board. For example, the circuit board 1 is designed to be a hollow three-dimensional structure, and the receiving cavity 10 is formed inside the circuit board. In this embodiment, the circuit board 1 includes a bottom plate 12 and a surrounding wall 13 extending from the bottom plate 12 to a direction close to the housing 2 and surrounding the receiving cavity 10, and the housing 2 is fixed to the bottom plate 12 and spaced from the surrounding wall 13. The circuit board 1 can be integrally formed, namely the circuit board 1 with the accommodating cavity 10 in the middle is arranged; or the upper and lower layers of circuit boards together enclose to form a containing cavity, such as a sandwich structure in this embodiment.

The shell 2 is fixedly covered on the circuit board 1 and covers the through hole 11, and the shell 2 and the circuit board 1 jointly enclose a resonant cavity 20. I.e. the through hole 11 communicates with the resonator cavity 20.

In the present embodiment, the housing 2 includes a housing plate 21 facing the circuit board 1 with a gap therebetween, and a side plate 22 bent and extended from a peripheral edge of the housing plate 21 in the direction of the circuit board 1 and fixed to the bottom plate 12.

The MEMS (micro electro Mechanical Systems) microphone 3, i.e. a micro electro Mechanical system microphone, is accommodated in the accommodating cavity 10 and electrically connected to the circuit board 1. The MEMS microphone 3 is shielded by the circuit board 1 and the shell 2, so that the electromagnetic shielding effect is improved, and the MEMS microphone is prevented from being interfered by other electronic components. The MEMS microphone 3 includes a base 31 fixed on the circuit board 1 and having a back cavity 30, a first diaphragm 32 supported on one end of the base 31 far away from the through hole 11, and a back plate 33.

The first diaphragm 32 and the back plate 33 form a capacitor structure at an interval, and the size of the capacitor generated by the MEMS microphone 3 is changed by changing the distance between the first diaphragm 32 and the back plate 33, so as to change the electrical signal.

The base 31 surrounds the through hole 11 and communicates the back chamber 30 with the through hole 11.

The diaphragm assembly 4 is accommodated in the resonant cavity 20 and divides the resonant cavity 20 into a first cavity 201 and a second cavity 202, and the first cavity 201 is communicated with the back cavity 30 through the through hole 11.

When a vibration signal or a pressure signal is input to the vibration sensor 100, for example, when a vibration signal or a pressure signal is input to a side of the housing 2 away from the resonant cavity 20 and/or a side of the circuit board 1 away from the accommodating cavity 10, the vibration element 4 vibrates and changes the air pressure in the resonant cavity 20. The air pressure change causes the first diaphragm 32 of the MEMS microphone 3 to vibrate, and changes the distance between the first diaphragm 32 and the back plate 33, that is, changes the capacitance generated by the MEMS microphone 3, so as to convert a vibration signal into an electrical signal, and transmit the converted electrical signal to the circuit board 1, so that the MEMS microphone 3 converts an external input vibration signal or pressure signal into an electrical signal, and converts the vibration signal into the electrical signal. For example, the circuit board 1 and/or the housing 2 of the vibration sensor 100 is attached to the neck, and when a person speaks, bone conduction is achieved to transmit vibration signals, so that the above conversion process is achieved.

In the process, the MEMS microphone 3 detects the external input vibration signal through the internal air pressure change caused by the vibration of the vibrating diaphragm component 4, so that the MEMS microphone 3 can ensure to accurately detect the change of the air pressure to the maximum extent, particularly has accurate response to the high-frequency vibration greater than 1KHz, and effectively improves the sensitivity and reliability of the vibration sensor 100.

Because the performance of the MEMS microphone 3 is stable under different temperature conditions, the sensitivity of the MEMS microphone is basically not influenced by factors such as temperature, vibration, temperature, time and the like, and the MEMS microphone has good reliability and high stability. Since the MEMS microphone 3 can be subjected to reflow soldering at a high temperature of 260 ℃ without affecting the performance, the basic performance with high accuracy can be achieved even if the audio debugging process is omitted after the assembly.

Preferably, in order to further improve the sensitivity of the vibration sensor 100, in the present embodiment, the vibration sensor further includes an ASIC (Application Specific Integrated Circuit) chip 5, and the ASIC chip 5 is accommodated in the accommodating cavity 10 and electrically connected to the MEMS microphone 3. The ASIC chip 5 provides external bias for the MEMS microphone 3, the effective bias can ensure that the MEMS microphone 3 can keep stable acoustic sensitivity and electrical parameters in the whole working temperature range, and microphone structure design with different sensitivities can be supported, and the design is more flexible and reliable.

In this embodiment, the housing 2 is provided with a first pressure relief hole 23 penetrating through the housing, specifically, the first pressure relief hole 23 penetrates through the housing plate 21, and when the SMT (surface mount technology) is assembled as a whole, the first pressure relief hole 23 is arranged to balance air pressure. Specifically, the outer shell plate 21 is attached to the inside of the mobile device through a surface assembly technology, and plugs the first pressure relief hole 23 to seal the resonant cavity 20, so that external air conduction acoustic signal interference is effectively avoided, and further the bone conduction sensitivity and the frequency characteristic of the vibration sensor 100 are improved. Of course, the position and number of the first pressure relief holes 23 are not limited thereto, and the principle is the same.

Similarly, the diaphragm assembly 4 is provided with a second pressure relief hole 40 penetrating therethrough, and the first cavity 201 is communicated with the second cavity 202 through the second pressure relief hole 40, so as to balance the air pressure balance between the second cavity 202 and the first cavity 201, that is, balance the air pressure balance between the second cavity 202 and the back cavity 30.

Specifically, the diaphragm assembly 4 includes a spacer 41 fixed to the circuit board 1 and disposed around the through hole 11, and a second diaphragm 42 fixed to a side of the spacer 41 away from the through hole 11. The gasket 41, the second diaphragm 42 and the circuit board 1 together enclose the first cavity 201. Namely, the spacer 41 is used to space the second diaphragm 42 from the circuit board 1 to provide a vibration space. Of course, the spacer 41 may be integrated with the second diaphragm 42. The second pressure relief hole 40 is disposed through the second diaphragm 42, and the position of the second pressure relief hole 40 is not limited thereto, and the principle is the same. In this embodiment, the diaphragm assembly 4 further includes a mass 43 fixedly connected to the second diaphragm 42. The mass 43 is attached to one side of the second diaphragm 42 close to the first cavity 201 and/or one side of the second diaphragm 42 close to the second cavity 202.

The vibrating diaphragm component 4 is accommodated in a resonant cavity 20 formed by enclosing the shell 2 and the circuit board 1, the shielding effect is better, and meanwhile, the volume of the cavity for generating air pressure change is increased, and the vibration effect is better.

As shown in fig. 3, the mass 43 is attached to a side of the second diaphragm 42 close to the second cavity 202. The mass block 43, the second diaphragm 42 and the spacer 41 are all located in the resonant cavity 20 of the circuit board 1, so that space is saved and production is facilitated.

Preferably, the area of the forward projection of the first diaphragm 32 on the circuit board 1 along the vibration direction thereof is smaller than the area of the forward projection of the second diaphragm 42 on the circuit board 1 along the vibration direction thereof. This structural design second vibrating diaphragm 42 is bigger with gaseous area of contact in the resonant cavity 20, makes its better vibrating gas, and first vibrating diaphragm 32 area is less relatively for MEMS microphone 3 can produce lower vibration coupling to the PCB noise that arouses by the speaker of installing on same PCB, and acoustic performance is better, facilitates the use.

Fig. 4 is a schematic structural diagram of a second embodiment of a fixing manner of a mass and a second diaphragm of the vibration sensor in the embodiment of fig. 1. The vibration sensor 200 of this embodiment is distinguished in that: the mass 243 is attached to a side of the second diaphragm 242 close to the first cavity 2101. The variation of this embodiment reduces the occupancy of the mass 243 on the volume of the second cavity 2102, increasing the volume of the second cavity 2102, further improving the sensitivity of the vibration sensor 200. Otherwise, it is the same as the embodiment shown in fig. 1 and will not be described herein.

Fig. 5 is a schematic structural diagram of a third embodiment of a fixing manner of a mass and a second diaphragm of the vibration sensor in fig. 1. The vibration sensor 300 of this embodiment is distinguished in that: the mass 343 is attached to a side of the second diaphragm 342 near the first cavity 3101 and a side of the second diaphragm 342 near the second cavity 3102. That is, the mass 343 includes two sets of masses, which are respectively attached to two opposite sides of the second diaphragm 342. This structural design further increases the amount of inertia of the vibration assembly 34, thereby further improving sensitivity. Otherwise, it is the same as the embodiment shown in fig. 1 and will not be described herein.

Please refer to fig. 6, which is a schematic structural diagram of another embodiment of the mass block in fig. 3 after structural changes. In the vibration sensor 400 of this embodiment, the mass 443 on the same side of the second diaphragm 442 includes a plurality of mass units 4431 spaced apart from each other. This structural design also increases the amount of inertia of the diaphragm assembly 44, and the diaphragm assembly 44 is more susceptible to vibration to further increase sensitivity. Otherwise, it is the same as the embodiment shown in fig. 3 and will not be described herein.

Please refer to fig. 7, which is a schematic structural diagram of a fourth embodiment of the fixing manner of the mass block and the diaphragm in the vibration sensor of the present invention. Compared with other embodiments of the present invention, the main difference is that the mass block 543 is wrapped by the second diaphragm 542 to form a fixing.

Specifically, the second diaphragm 542 includes two second sub-diaphragms 5421 fixed to the spacer 541 and stacked on each other, and the mass block 543 is sandwiched and wrapped between the two second sub-diaphragms 5421. This structural design has increased the fixed intensity of quality piece 543, has further improved the reliability.

The above embodiments of the present invention are only described, and it should be noted that, for those skilled in the art, modifications can be made without departing from the inventive concept, but these all fall into the protection scope of the present invention.

Claims

1. A vibration sensor, characterized in that the vibration sensor comprises:

when the vibration sensor inputs a vibration signal or a pressure signal, the vibrating diaphragm component vibrates, and air pressure in the resonant cavity is changed.

2. The vibration sensor of claim 1, further comprising an ASIC chip housed in the housing cavity and electrically connected to the MEMS microphone.

3. The vibration sensor according to claim 1, wherein the circuit board includes a bottom plate and a surrounding wall extending from the bottom plate toward the housing and surrounding the housing cavity, and the housing is fixed to the bottom plate and spaced apart from the surrounding wall.

4. The vibration sensor according to claim 1, wherein the housing includes a housing plate spaced apart from and opposed to the circuit board, and a side plate bent and extended from a peripheral edge of the housing plate toward the circuit board and fixed to the circuit board, and the first pressure release hole penetrates through the housing plate.

5. The vibration sensor of claim 1, wherein the diaphragm assembly includes a spacer fixed to the circuit board and surrounding the through hole, and a second diaphragm fixed to a side of the spacer away from the through hole, the spacer, the second diaphragm and the circuit board together enclose the first cavity, and the second pressure relief hole penetrates through the second diaphragm.

6. The vibratory sensor of claim 5 wherein the diaphragm assembly further comprises a mass fixedly connected to the second diaphragm; the mass block is attached to one side of the second diaphragm close to the first cavity and/or one side of the second diaphragm close to the second cavity.

7. The vibrating sensor of claim 6, wherein the mass on the same side of the second diaphragm comprises a plurality of spaced mass elements.

8. The vibratory sensor of claim 5 wherein the diaphragm assembly further comprises a mass secured by the second diaphragm wrap.

9. The vibration sensor according to claim 8, wherein the second diaphragm includes two second sub-diaphragms fixed to the spacer and stacked on each other, and the mass is sandwiched and wrapped between the two second sub-diaphragms.

10. The vibration sensor of claim 5, wherein an area of an orthographic projection of the first diaphragm toward the circuit board in the vibration direction thereof is smaller than an area of an orthographic projection of the second diaphragm toward the circuit board in the vibration direction thereof.