CN220123072U

CN220123072U - MEMS microphone

Info

Publication number: CN220123072U
Application number: CN202321357330.7U
Authority: CN
Inventors: 邓小林; 唐向东
Original assignee: Wanmo Acoustics Co ltd
Current assignee: Wanmo Acoustics Co ltd
Priority date: 2023-05-31
Filing date: 2023-05-31
Publication date: 2023-12-01
Anticipated expiration: 2033-05-31

Abstract

The utility model discloses an MEMS microphone, which comprises a shell and a PCB, wherein an ASIC chip and an MEMS chip are arranged on the PCB, and a sound hole is arranged on the shell; an inner shielding layer and a first outer shielding layer are respectively arranged on the inner side and the outer side of the shell, a protective film is arranged at the position, corresponding to the sound hole, of the inner side of the shell, and the protective film is arranged on the inner side of the shell through a fixed block; the surface of PCB board is provided with the second outer shielding layer, the MEMS chip is equipped with the bleeder valve including base, vibrating diaphragm and the back polar plate that range upon range of setting, the upper surface of vibrating diaphragm, play anti radio frequency shielding function, thereby play dual shielding effect, through the design of bleeder valve, let the vibrating diaphragm can not produce big whole deformation or inhale mutually with the back polar plate, ensure that the electric capacity changes steadily between vibrating diaphragm and the back polar plate, make it can let the MEMS microphone use on the voiceprint discernment, steady electric capacity changes and lets the ripple stability of sound better.

Description

MEMS microphone

Technical Field

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

Background

MEMS (micro electro mechanical system) microphones are microphones manufactured based on MEMS technology, and compared with conventional microphones, MEMS microphones can be manufactured by a surface mount technology, can withstand very high reflow soldering temperatures, are easy to integrate with CMOS technology and other audio circuits, have improved noise cancellation performance and good RF and EMI suppression performance, and are currently used in a large number of intelligent terminal fields such as voice communication, intelligent voice interaction, voiceprint recognition, and the like. The MEMS microphone has the characteristics of small volume, good frequency response, low noise, etc., and along with the development of miniaturization and thinning of electronic equipment, the MEMS microphone is rapidly developed, and the cost is lower and lower.

The existing MEMS microphone comprises a circuit board and a cover body, wherein the cover body is covered on the circuit board to form a hollow shell, an MEMS chip and an application specific integrated circuit ASIC chip are arranged on the circuit board, an acoustic hole communicated with the MEMS chip is further formed in the circuit board, external sound enters from the acoustic hole and is transmitted to the MEMS chip, the ASIC chip detects the change of capacitance and converts the change into an electric signal to be transmitted to related electronic elements for processing, and in general, the cover body on the circuit board is of a metal structure and can play a role of shielding, so that the internal MEMS chip and ASIC chip can be prevented from being interfered by external electromagnetic waves. However, with the increase of the functions that can be realized by the electronic products and the increase of the number of the electronic components therein, the structural design of the single cover body easily causes the MEMS microphone to be radiated onto the chip by the external radio frequency interference signal, the interference signal is coupled to the output end to form interference noise, so that the problem of radio frequency interference exists, and the acoustic performance of the MEMS microphone is affected.

Therefore, a new technical solution is needed to solve the above problems.

Disclosure of Invention

In view of the foregoing, the present utility model aims at overcoming the drawbacks of the prior art, and it is a primary object of the present utility model to provide a MEMS microphone, which has an anti-radio frequency shielding function by providing an inner shielding layer and a first outer shielding layer on the inner and outer sides of a housing, respectively, so as to shield radio frequency interference, thereby having a double shielding function, and the diaphragm does not generate a large integral deformation or attract with a back plate through an air release valve.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

the MEMS microphone comprises a shell and a PCB, wherein the shell and the PCB are enclosed to form a containing cavity, an ASIC chip and an MEMS chip are arranged on the PCB, the ASIC chip is electrically connected with the MEMS chip through a metal wire, and an acoustic hole communicated with the containing cavity is arranged on the shell;

an inner shielding layer and a first outer shielding layer are respectively arranged on the inner side and the outer side of the shell, and the inner shielding layer and the first outer shielding layer are integrally injection molded with the shell; a protective film is arranged at the position, corresponding to the sound hole, of the inner side of the shell, and the protective film is arranged on the inner side of the shell through a fixed block;

the outer surface of the PCB is provided with a second outer shielding layer, and the second outer shielding layer is provided with a contact; the MEMS chip comprises a base, a vibrating diaphragm and a back electrode plate which are arranged in a stacked manner, wherein the back electrode plate is provided with a plurality of exhaust holes penetrating through the back electrode plate; and a plurality of air release valves are arranged on the upper surface of the central area of the vibrating diaphragm.

As a preferable scheme, the fixing block is made of metal or plastic, and is adhered to the inner side of the shell.

As a preferable scheme, the fixing block is provided with a placement position for installing and positioning the protective film, the protective film is positioned between the shell and the protective block, so that the tight connection between the protective film and the shell is ensured, and the protective film is prevented from tilting and falling off.

As a preferred scheme, the protection film includes PTFE rete and fixed plate, the PTFE rete sets up in the upper surface of fixed plate, the PTFE rete laminating is in the inboard of shell, the fixed plate supports in placing the position, be provided with a plurality of sound holes on the fixed plate.

As a preferable scheme, the inner shielding layer and the first outer shielding layer are made of copper, and the electromagnetic shielding effect of the inner shielding layer and the first outer shielding layer made of copper is better, so that the performance of a product is better ensured.

As a preferable scheme, the PCB is provided with an MEMS chip mounting position and an ASIC chip mounting position, the MEMS chip and the ASIC chip are respectively arranged on the MEMS chip mounting position and the ASIC chip mounting position, and a waterproof net is further arranged between the MEMS chip mounting position and the MEMS chip, so that the MEMS microphone has a good waterproof function, and the service life is prolonged.

As a preferred scheme, the MEMS chip is fixed on the MEMS chip mounting position by silicone.

As a preferred embodiment, the ASIC chip is fixed to the ASIC chip mounting site by epoxy glue.

Compared with the prior art, the utility model has obvious advantages and beneficial effects, in particular, the technical proposal shows that the utility model mainly utilizes the double-layer design of the inner shielding layer and the first outer shielding layer to play a role of resisting radio frequency interference by respectively arranging the inner shielding layer and the first outer shielding layer at the inner side and the outer side of the shell so as to play a role of double shielding, and the inner shielding layer and the outer shielding layer are mutually separated and distributed, thereby avoiding interference signals from forming crosstalk, improving the acoustic performance of the MEMS microphone, and simultaneously, the shell can play a role of shielding the radio frequency interference and improving the acoustic performance of the MEMS microphone; and the MEMS microphone can be protected from environmental pollution from the outside through the structural design of the protective film.

Still just through the design of air release valve on the vibrating diaphragm for MEMS microphone is at little acoustic pressure or when no acoustic pressure is inoperative, and air release valve and vibrating diaphragm face parallel and level when the vibrating diaphragm receives overload big acoustic pressure air current suddenly, and the air release valve can open voluntarily and leak unnecessary overload air current, lets the vibrating diaphragm can not produce big whole deformation or inhale mutually with the back plate, ensures that the electric capacity change between vibrating diaphragm and the back plate is stable, and the electric signal of output changes can not negligence greatly, makes it can let MEMS microphone use on the voiceprint discernment, and steady electric capacity changes and lets the ripple stability of sound better, and the people's voice discernment algorithm system is more easy quick accurate discernment people's voice matches.

In order to more clearly illustrate the structural features and efficacy of the present utility model, the present utility model will be described in detail below with reference to the accompanying drawings and examples.

Drawings

FIG. 1 is a perspective view of an embodiment of the present utility model;

FIG. 2 is a cross-sectional view of an embodiment of the present utility model;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

FIG. 4 is a partial enlarged view at B in FIG. 2;

FIG. 5 is a cross-sectional view of a MEMS chip according to an embodiment of the utility model.

The attached drawings are used for identifying and describing:

10. housing 11, accommodation chamber

12. Sound hole 13, inner shielding layer

14. First outer shielding layer 15, protective film

151. PTFE film 152 and fixing plate

16. Fixed block 161, placement position

20. PCB 21 and ASIC chip

22. MEMS chip 23, second outer shielding layer

24. Contact 221, base

222. Vibrating diaphragm 223 and back plate

224. Exhaust hole 225 and air release valve

25. MEMS chip mounting position 26, ASIC chip mounting position

27. A waterproof net.

Detailed Description

Referring to fig. 1 to 5, specific structures of embodiments of the present utility model are shown.

In the description of the present utility model, it should be noted that, for the azimuth words, terms such as "upper", "lower", "front", "rear", "left", "right", etc., indicate azimuth and positional relationships as shown based on the drawings or when worn normally, only for convenience of describing the present utility model and simplifying the description, but do not indicate or imply that the device or element to be referred must have a specific azimuth, be configured and operated in a specific azimuth, and should not be construed as limiting the specific protection scope of the present utility model.

A MEMS microphone includes a housing 10 and a PCB 20.

The shell 10 and the PCB 20 enclose to form a containing cavity 11, the PCB 20 is provided with an ASIC chip 21 and an MEMS chip 22, the ASIC chip 21 is electrically connected with the MEMS chip 22 through a metal wire, and the shell 10 is provided with an acoustic hole 12 communicated with the containing cavity 11.

An inner shielding layer 13 and a first outer shielding layer 14 are respectively arranged on the inner side and the outer side of the shell 10, and the inner shielding layer 13 and the first outer shielding layer 14 are integrally injection molded with the shell 10; preferably, the inner shielding layer 13 and the first outer shielding layer 14 are made of copper, and the electromagnetic shielding effect of the inner shielding layer 13 and the first outer shielding layer 14 made of copper is better, so that the performance of the product is better ensured. The inner side of the housing 10 corresponds to the sound hole 12 and is provided with a protective film 15, the protective film 15 comprises a PTFE film layer 151 and a fixing plate 152, the PTFE film layer 151 is arranged on the upper surface of the fixing plate 152, and the PTFE film layer 151 is attached to the inner side of the housing 10.

The protective film 15 is arranged on the inner side of the shell 10 through a fixed block 16; the fixed block 16 has a placement position 161 for the mounting and positioning of the protective film 15, the protective film 15 being located between the housing 10 and the protective block. The fixing plate 152 abuts against the placement position 161, and a plurality of sound transmission holes are formed in the fixing plate 152. Preferably, the fixing block 16 is made of metal or plastic, and the fixing block 16 is adhered to the inner side of the housing 10.

The outer surface of the PCB 20 is provided with a second outer shielding layer 23, and the second outer shielding layer 23 is provided with a contact 24; the MEMS chip 22 includes a base 221, a diaphragm 222 and a back plate 223 which are stacked, and the back plate 223 has a plurality of air vents 224 penetrating the back plate 223; the upper surface of the central region of the diaphragm 222 is provided with a plurality of air release valves 225. The air release valve 225 includes a valve flap and an air release hole disposed on the main body of the diaphragm 222, where the valve flap is movably connected to the diaphragm 222, and the valve flap extends into the air release hole. The air release valve 225 is a tongue-shaped air release valve. When the MEMS microphone is not working at low sound pressure or no sound pressure, the air release valve 225 is flush with the surface of the vibrating diaphragm 222, when the vibrating diaphragm 222 is suddenly subjected to overload high-sound pressure air flow, the air release valve 225 can automatically open and release redundant overload air flow, so that the vibrating diaphragm 222 can not generate large integral deformation or attract the back polar plate 223, the stable change of capacitance between the vibrating diaphragm 222 and the back polar plate 223 is ensured, the output electric signal change can not be negligent or negligent, the MEMS microphone can be applied to voiceprint recognition, the stable change of capacitance enables the ripple stability of sound to be better, and the voice recognition algorithm system can more easily, quickly and accurately recognize voice matching.

Voiceprint recognition, one of the biometric techniques, also known as speaker recognition, is of two types, speaker recognition and speaker verification. Different tasks and applications may use different voiceprint recognition techniques, such as recognition techniques when narrowing criminal investigation, and confirmation techniques when transacting banks. Voiceprint recognition is to convert an acoustic signal into an electrical signal and then to recognize the electrical signal by a computer.

The voiceprint recognition has some special advantages that (1) the voice containing voiceprint features is convenient and natural to acquire, and voiceprint extraction can be completed unknowingly, so that the acceptance of users is high; (2) The recognition cost for acquiring the voice is low, the use is simple, one microphone is needed, and extra recording equipment is not needed when the communication equipment is used; (3) The method is suitable for remote identity confirmation, and can realize remote login through a network (communication network or internet) by only one microphone or telephone and mobile phone; (4) the algorithm complexity of voiceprint recognition and confirmation is low; (5) The accuracy can be improved by combining with other measures such as content authentication by voice recognition. The advantage of voiceprint recognition clearly only has stable capacitance change, so that the stability of the voiceprint of the voice is better, and the voice recognition algorithm system is easier to quickly and accurately recognize voice matching.

The PCB 20 is provided with a MEMS chip mounting position 25 and an ASIC chip mounting position, the MEMS chip and the ASIC chip 21 are respectively arranged on the MEMS chip mounting position 25 and the ASIC chip mounting position, and preferably, the MEMS chip 22 is fixed on the MEMS chip mounting position 25 through silica gel. Preferably, the ASIC chip 21 is fixed to the ASIC chip mounting site by epoxy. A waterproof net 27 is also arranged between the MEMS chip mounting position 25 and the MEMS chip. In this embodiment, the waterproof net 27, the MEMS chip 22 and the ASIC chip 21 are fixed at corresponding positions of the PCB 20 by an adhesive, wherein the waterproof net 27, the MEMS chip 22 are bonded with a silica gel having stress resistance and buffering effects, the SIC chip is bonded with an epoxy gel, and the MEMS chip 22, the ASIC chip 21 and the PCB 20 are electrically connected by bonding wires.

The utility model mainly adopts the design that the inner shielding layer and the first outer shielding layer are respectively arranged on the inner side and the outer side of the shell, and the double-layer design of the inner shielding layer and the first outer shielding layer is utilized to play a role in resisting radio frequency interference so as to play a role in double shielding, and the inner shielding layer and the outer shielding layer are mutually spaced, so that interference signals are prevented from forming crosstalk, the acoustic performance of the MEMS microphone is improved, and meanwhile, the shell can play a role in shielding the radio frequency interference, and the acoustic performance of the MEMS microphone is improved; and the MEMS microphone can be protected from environmental pollution from the outside through the structural design of the protective film.

The foregoing description is only a preferred embodiment of the present utility model, and is not intended to limit the technical scope of the present utility model, so any minor modifications, equivalent changes and modifications made to the above embodiments according to the technical principles of the present utility model are still within the scope of the technical solutions of the present utility model.

Claims

1. The MEMS microphone comprises a shell and a PCB, wherein the shell and the PCB are enclosed to form a containing cavity, an ASIC chip and an MEMS chip are arranged on the PCB, the ASIC chip is electrically connected with the MEMS chip through a metal wire, and an acoustic hole communicated with the containing cavity is arranged on the shell; the method is characterized in that:

2. A MEMS microphone as defined by claim 1 wherein: the fixed block is made of metal or plastic, and is adhered to the inner side of the shell.

3. A MEMS microphone as defined by claim 1 wherein: the fixed block is provided with a placement position for installing and positioning a protective film, and the protective film is positioned between the shell and the protective block.

4. A MEMS microphone according to claim 3, wherein: the protection film includes PTFE rete and fixed plate, the PTFE rete sets up in the upper surface of fixed plate, the PTFE rete laminating is in the inboard of shell, the fixed plate supports in placing the position, be provided with a plurality of sound holes on the fixed plate.

5. A MEMS microphone as defined by claim 1 wherein: the inner shielding layer and the first outer shielding layer are made of copper.

6. A MEMS microphone as defined by claim 1 wherein: the PCB is provided with an MEMS chip mounting position and an ASIC chip mounting position, the MEMS chip and the ASIC chip are respectively arranged on the MEMS chip mounting position and the ASIC chip mounting position, and a waterproof net is further arranged between the MEMS chip mounting position and the MEMS chip.

7. A MEMS microphone as defined by claim 1 wherein: the MEMS chip is fixed on the MEMS chip mounting position through silica gel.

8. A MEMS microphone as defined by claim 1 wherein: the ASIC chip is fixed on the ASIC chip mounting position through epoxy glue.