WO2022062001A1

WO2022062001A1 - Bone conduction microphone and mobile terminal

Info

Publication number: WO2022062001A1
Application number: PCT/CN2020/121815
Authority: WO
Inventors: 张金宇
Original assignee: 瑞声声学科技(深圳)有限公司
Priority date: 2020-09-25
Filing date: 2020-10-19
Publication date: 2022-03-31
Also published as: CN213342678U

Abstract

Provided in the present utility model are a bone conduction microphone and a mobile terminal. The microphone comprises a first base plate, a second base plate, a cover plate, a backing plate, a first diaphragm, and a housing, which are stacked in sequence. The first base plate, the second base plate, and the cover plate enclose to form a rear cavity. The cover plate, the backing plate, and the first diaphragm enclose to form a middle cavity. The first diaphragm and the housing enclose form a front cavity. The first diaphragm is provided with a first vent hole, and the position on the cover plate corresponding to the first vent hole is provided with a second vent hole. The microphone also comprises an inverted tube that penetrates through the backing plate and is connected the first vent hole and the second vent hole, as well as a MEMS chip that is located in the rear cavity and is provided on an inner side of the cover plate. The MEMS chip has a back cavity and a second diaphragm. A vent hole connecting the back cavity and the rear cavity is formed on the second diaphragm, and an acoustic hole is provided on the cover plate in correspondence with the back cavity. The present utility model can effectively improve the sensitivity of a bone conduction microphone.

Description

Bone conduction microphone and mobile terminal

technical field

The utility model relates to the technical field of micro-electromechanical systems, in particular to a bone conduction microphone and a mobile terminal.

Background technique

Microphone, scientific name is microphone, translated from English microphone (microphone), also known as microphone or microphone, which is an energy conversion device that converts sound signals into electrical signals. In recent years, MEMS microphones (such as bone conduction microphones) based on MEMS (Micro Electro-Mechanical Systems) technology have been used in a variety of applications due to their improved noise cancellation performance and good RF (Radio Frequency) and EMI (Electromagnetic Interference) suppression performance. It shows many advantages, especially in mid-to-high-end mobile phone applications.

The structure of the existing bone conduction microphone is usually divided into three independent cavities, and the three cavities are not associated with each other, resulting in low sensitivity of the bone conduction microphone.

Therefore, it is necessary to improve the structure of the above-mentioned bone conduction microphone.

technical problem

The purpose of the present invention is to provide a bone conduction microphone and a mobile terminal, aiming at solving the problem of low sensitivity of the existing bone conduction microphone.

technical solutions

The technical scheme of the present utility model is as follows:

A first aspect of the embodiments of the present utility model provides a bone conduction microphone, including:

A first substrate, a second substrate disposed on the first substrate and having a first hollow portion, a cover plate disposed on the second substrate, a pad disposed on the cover plate and having a second hollow portion a plate, a first diaphragm arranged on the backing plate, a casing arranged on the first diaphragm, located between the first diaphragm and the casing and arranged on the first diaphragm The mass block on the membrane, the first substrate, the second substrate and the cover plate are enclosed to form a back cavity, the cover plate, the backing plate and the first diaphragm are enclosed to form a middle cavity, the first diaphragm and the shell The body is enclosed to form a front cavity, the first diaphragm is provided with a first vent hole, the cover plate is provided with a second vent hole corresponding to the position of the first vent hole, and the bone conduction microphone further includes a through hole. The backing plate is connected to the inverter tube of the first air vent hole and the second air vent hole, and the MEMS chip is located in the back cavity and arranged on the inner side of the cover plate, and the MEMS chip has a back cavity and a first air vent. A second vibrating membrane, the second vibrating membrane is formed with a ventilation hole connecting the back cavity and the back cavity, and a sound hole is opened on the cover plate at a position corresponding to the back cavity.

In some implementations, the microphone further includes an ASIC chip located in the back cavity and disposed inside the cover plate, and the ASIC chip is electrically connected to the MEMS chip.

In some implementations, a third vent hole is formed on the backing plate at a position corresponding to the first vent hole, and the inverting tube is located in the third vent hole and communicated with the first vent hole and the Second vent.

In some embodiments, the number of the second substrates is two or more.

In some embodiments, the housing includes a housing body, a support portion surrounding the housing body and extending toward the first diaphragm.

A second aspect of the embodiment of the present invention provides a mobile terminal, including the bone conduction microphone according to the first aspect of the embodiment of the present invention.

beneficial effect

As can be seen from the above description, compared with the prior art, the beneficial effects of the present utility model are:

When the mass block drives the first diaphragm to move towards the cover plate, the middle cavity is compressed (the pressure increases), and the front cavity is stretched (the pressure decreases). Combined with the rear cavity into a large cavity, the compliance of the microphone is improved, thereby improving the sensitivity of the microphone. At the same time, due to the functions of the ventilation holes on the second diaphragm of the MEMS chip, the back cavity of the MEMS chip and the acoustic holes on the cover plate, the back cavity is connected to the middle cavity. The pressure of the formed cavity is reduced, and a reverse pressure is applied on the side of the first diaphragm facing the cover plate, which further improves the sensitivity of the bone conduction microphone.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that are required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some, but not all, embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the provided drawings without any creative effort.

1 is a schematic structural diagram of a bone conduction microphone provided by an embodiment of the present invention;

2 is an exploded schematic diagram of a bone conduction microphone provided by an embodiment of the present invention;

3 is a cross-sectional view of the bone conduction microphone provided by an embodiment of the present invention along the direction A-A in FIG. 1;

FIG. 4 is a module block diagram of a mobile terminal provided by an embodiment of the present invention.

Embodiments of the present invention

In order to make the purpose, technical solutions and advantages of the present utility model clearer, the present utility model will be described in further detail below in conjunction with the accompanying drawings and embodiments, wherein the same or similar reference numerals represent the same or similar elements or have the same or similar elements throughout. functional element. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

Example 1

Please refer to FIG. 1 , FIG. 2 and FIG. 3 , FIG. 1 is a schematic structural diagram of a bone conduction microphone provided by an embodiment of the present invention, FIG. 2 is an exploded schematic diagram of a bone conduction microphone provided by an embodiment of the present invention, and FIG. 3 is the present invention A cross-sectional view of the bone conduction microphone provided by the novel embodiment along the AA direction in FIG. 1 .

As shown in FIGS. 1 to 3 , the bone conduction microphone provided by the first embodiment of the present invention includes a first base plate 1 , a second base plate 2 disposed on the first base plate 1 and having a first hollow portion 21 , The cover plate 3 arranged on the second base plate 2, the backing plate 4 arranged on the cover plate 3 and having the second hollow portion 41, the first diaphragm 5 arranged on the backing plate 4, the The casing 6 on the first diaphragm 5, the mass block 7 located between the first diaphragm 5 and the casing 6 and disposed on the first diaphragm 5, the first diaphragm 5 The substrate 1 , the second substrate 2 and the cover plate 3 are enclosed to form a rear cavity 13 , the cover plate 3 , the backing plate 4 and the first diaphragm 5 are enclosed to form a middle cavity 12 , the first diaphragm 5 and the casing 6. The front cavity 11 is formed by enclosing, the first diaphragm 5 is provided with a first vent hole 51, the cover plate 3 is provided with a second vent hole 31 corresponding to the position of the first vent hole 51, and the The bone conduction microphone also includes an inverted tube 8 penetrating the backing plate 4 and communicating with the first air vent hole 51 and the second air vent hole 31 . MEMS chip 9, the MEMS chip 9 has a back cavity 91 and a second diaphragm 92, the second diaphragm 92 is formed with a ventilation hole 93 connecting the back cavity 91 and the back cavity 13, the cover plate 3 A sound hole 32 is opened at a position corresponding to the back cavity 91 . It should be understood that the annular channel enclosed by the arrow B in FIG. 3 is an air flow channel. Due to the combined action of the first air vent 51 , the second air vent 31 , the inverted tube 8 , the vent hole 93 and the sound hole 32 , the The front cavity 11 , the rear cavity 13 and the middle cavity 12 communicate with each other.

It should be noted that, due to the MEMS process, the vent hole 93 formed on the second diaphragm 92 can be easily processed to several microns, thereby ensuring a flat frequency response of the bone conduction microphone.

It should also be noted that, in this embodiment, there are two second substrates 2 , and they are sequentially stacked on the first substrate 1 . It should be understood that, in other embodiments, the number of the second substrates 2 may be increased or decreased according to specific application conditions.

In addition, the materials of the cover plate 3 and the casing 6 in this embodiment are both metal.

In the bone conduction microphone provided by the first embodiment of the present invention, when the mass block 7 drives the first diaphragm 5 to move in the direction of the cover plate 3 , the middle cavity 12 is compressed (the pressure increases), and the front cavity 11 is stretched ( pressure decreases), since the inverter tube 8 is connected to the front cavity 11 and the rear cavity 13, the front cavity 11 and the rear cavity 13 are combined into a large cavity, which improves the compliance of the bone conduction microphone, thereby improving the bone conduction microphone. sensitivity. At the same time, due to the functions of the vent hole 93 on the second diaphragm 92 of the MEMS chip 9, the back cavity 91 of the MEMS chip 9 and the acoustic hole 32 on the cover plate 3, the back cavity 13 is connected to the middle cavity 12, and the middle cavity When the pressure of 12 increases, the pressure of the cavity formed by the front cavity 11 and the rear cavity 13 decreases, and a reverse pressure is applied on the side of the first diaphragm 5 toward the cover plate 3, which further improves the sensitivity of the bone conduction microphone.

Example 2

Please refer to FIG. 2 and FIG. 3 , FIG. 2 is an exploded schematic view of the bone conduction microphone provided by the embodiment of the present invention, and FIG. 3 is a cross-sectional view of the bone conduction microphone provided by the embodiment of the present invention along the direction A-A in FIG. 1 .

Compared with the bone conduction microphone provided by the first embodiment of the present invention, the second embodiment of the present invention adds an ASIC chip 10 .

As shown in FIG. 2 , the bone conduction microphone in this embodiment further includes an ASIC chip 10 located in the back cavity 13 and disposed inside the cover plate 3 , and the ASIC chip 10 is electrically connected to the MEMS chip 9 . .

It should be understood that when the capacitance of the MEMS chip 9 changes (indicating that it has received the sound wave signal), the MEMS chip 9 sends the sound wave signal to the ASIC chip 10 for processing, and the corresponding signal can be obtained and output to complete the sound transmission.

As shown in FIG. 2 , in this embodiment, in order to ensure the communication between the inverter tube 8 and the first air vent hole 51 and the second air vent hole 31 , a position of the backing plate 4 corresponding to the first air vent hole 51 is provided. The third vent hole 42 is formed. At this time, the inverter tube 8 is located in the third vent hole 42 and communicated with the first vent hole 51 and the second vent hole 31 .

As shown in FIG. 3, in order to ensure that the front cavity 11 can be formed between the casing 6 and the first diaphragm 5, the casing 6 in this embodiment includes a casing body 61, which surrounds the casing body 61 and faces the The support portion 62 extending in the direction of the first diaphragm 5 is in contact with the first diaphragm 5 at one end of the support portion 62 away from the housing body 61 .

Example 3

Please refer to FIG. 4 , which is a block diagram of a module of a mobile terminal according to an embodiment of the present invention.

As shown in FIG. 4 , the mobile terminal 100 provided by the third embodiment of the present invention includes the bone conduction microphone 101 provided by the first embodiment and/or the second embodiment of the present invention.

It should be understood that the mobile terminal 100 provided in this embodiment includes, but is not limited to, a mobile phone, a notebook computer, a tablet computer, a POS machine, and a vehicle-mounted computer.

It should be noted that each embodiment in the content of the present utility model is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts of each embodiment are mutually See it.

It should also be noted that, in the context of this disclosure, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these There is no such actual relationship or sequence between entities or operations. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion such that a process, method, article or device comprising a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above description of the disclosed embodiments enables those skilled in the art to implement or use the content of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined in this disclosure may be implemented in other implementations without departing from the spirit or scope of this disclosure. implemented in the example. Accordingly, this disclosure is not to be limited to the embodiments shown in this disclosure, but is to be accorded the widest scope consistent with the principles and novel features disclosed in this disclosure.

Claims

A bone conduction microphone includes a first base plate, a second base plate disposed on the first base plate and having a first hollow portion, a cover plate disposed on the second base plate, disposed on the cover plate and A backing plate with a second hollow portion, a first vibrating film arranged on the backing plate, and a housing provided on the first vibrating film, located between the first vibrating film and the housing and The mass block arranged on the first diaphragm, the first substrate, the second substrate and the cover plate are enclosed to form a back cavity, and the cover plate, the backing plate and the first diaphragm are enclosed to form a middle cavity, so The first diaphragm and the casing are enclosed to form a front cavity, and it is characterized in that a first air vent hole is opened on the first diaphragm, and a second air vent is opened on the cover plate corresponding to the position of the first air vent hole. A vent hole, the bone conduction microphone further includes an inverted tube penetrating the backing plate and communicating with the first vent hole and the second vent hole, a MEMS located in the back cavity and arranged on the inner side of the cover plate The MEMS chip has a back cavity and a second diaphragm, the second diaphragm is formed with a ventilation hole connecting the back cavity and the back cavity, and the cover plate is opened at a position corresponding to the back cavity Sound hole.
The bone conduction microphone according to claim 1, further comprising an ASIC chip located in the back cavity and disposed inside the cover plate, the ASIC chip being electrically connected to the MEMS chip.
The bone conduction microphone according to claim 1, wherein a third vent hole is formed on the backing plate at a position corresponding to the first vent hole, and the phase inverting tube is located in the third vent hole and communicated with the first vent hole and the second vent hole.
The bone conduction microphone according to claim 1, wherein the number of the second substrates is two or more.
The bone conduction microphone according to claim 1, wherein the casing comprises a casing body, and a support portion surrounding the casing body and extending toward the first diaphragm.
A mobile terminal, comprising: the bone conduction microphone according to any one of claims 1-5.