CN115334428A

CN115334428A - Microphone assembly and electronic equipment

Info

Publication number: CN115334428A
Application number: CN202211255106.7A
Authority: CN
Inventors: 孟燕子; 荣根兰; 马丽
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2022-10-13
Filing date: 2022-10-13
Publication date: 2022-11-11
Anticipated expiration: 2042-10-13
Also published as: CN115334428B

Abstract

The application discloses microphone subassembly and electronic equipment. The microphone assembly comprises a substrate, a first supporting piece, a second supporting piece, two diaphragm assemblies and a back plate, wherein the back plate is provided with a hollow-out area and is positioned between the two diaphragm assemblies; each vibrating diaphragm component comprises a first vibrating diaphragm and a second vibrating diaphragm which is fixedly connected with the first vibrating diaphragm and arranged at intervals, the second vibrating diaphragm is positioned between the first vibrating diaphragm and the back plate, one end of the first vibrating diaphragm and one end of the back plate are respectively and fixedly connected with the first supporting piece, the other end of the first vibrating diaphragm and the other end of the back plate are respectively and fixedly connected with the second supporting piece, and the edge of the second vibrating diaphragm is suspended; the microphone assembly disclosed by the application has the advantages that the length-width ratio is high, the application range of a product is enlarged, and the sensitivity and the accuracy of electric signal detection of the microphone assembly are improved.

Description

Microphone assembly and electronic equipment

Technical Field

The invention relates to the technical field of microphones, in particular to a microphone assembly and electronic equipment.

Background

In recent years, micro-Electro-Mechanical systems (MEMS) microphones have been developed vigorously and are widely used in consumer electronics products such as high-end mobile phones, notebook computers, bluetooth headsets, etc. The MEMS microphones are a new type of microphones developed based on silicon micromachining technology, and among them, capacitive MEMS microphones are the focus of research and development.

The capacitive MEMS microphone includes a MEMS chip through which an acoustic signal is converted into an electrical signal. The MEMS chip comprises a substrate, a back plate and a vibrating diaphragm which are parallel to the substrate respectively, wherein the back plate and the vibrating diaphragm jointly form a parallel plate capacitor, the vibrating diaphragm is deformed when external sound pressure acts on the vibrating diaphragm, the distance between the vibrating diaphragm electrode and the back plate electrode is changed, the capacitor connected into a control Circuit is changed, voltage in the Circuit is further changed, and the electric signal change in the Circuit is detected through an Application Specific Integrated Circuit (ASIC), so that the detection of a sound signal is realized.

The sound pressure generally accepted by the condenser type MEMS microphone is relatively small, so that the sensitivity of the microphone is higher. In order to obtain higher sensitivity, the area of the diaphragm needs to be increased to improve the capacitance variation in the circuit, but the increase of the area of the diaphragm or the back plate can increase the production cost, and can also increase the length and the width of the microphone, so that the length and the width of the packaging structure of the microphone are increased, and finally, the packaging structure can only be applied to products with smaller length-to-width ratio, and the application range of the microphone is limited.

Disclosure of Invention

The present invention is directed to at least one of the technical problems of the prior art, and provides a microphone assembly and an electronic device.

The purpose of the invention is realized by adopting the following technical scheme:

according to an aspect of the present invention, there is provided a microphone assembly, including a substrate, a first supporting member and a second supporting member fixedly connected to the substrate, and two diaphragm assemblies and a back plate located between the first supporting member and the second supporting member, the back plate having a hollow area and being located between the two diaphragm assemblies, the substrate being provided with a cavity, the first supporting member partially closing one side of the cavity, the second supporting member being located in the cavity;

each diaphragm component comprises a first diaphragm and a second diaphragm which is fixedly connected with the first diaphragm and arranged at an interval, the second diaphragm is positioned between the first diaphragm and the back plate, one end of the first diaphragm and one end of the back plate are respectively and fixedly connected with the first supporting piece, the other end of the first diaphragm and the other end of the back plate are respectively and fixedly connected with the second supporting piece, the edge of the second diaphragm is suspended, and the first diaphragm, the back plate, the first supporting piece and the second supporting piece jointly divide the cavity into at least a vibration cavity and a back cavity;

one of the two diaphragm assemblies forms a first electrode, the other diaphragm assembly forms a second electrode, the back plate forms a third electrode, the first electrode and the second electrode form a first variable capacitor, the third electrode and the second electrode form a second variable capacitor, one side of the first electrode, which is far away from the back plate, is communicated with the back cavity, one side of the second electrode, which is far away from the back plate, is isolated from the back cavity, and the first variable capacitor and the second variable capacitor form a differential capacitor to sense a sound pressure signal.

Furthermore, the cavity is provided with two first inner surfaces perpendicular to the two diaphragm assemblies and the back plate and two second inner surfaces parallel to the two diaphragm assemblies and the back plate, three side surfaces of the second supporting piece are fixedly connected with the two first inner surfaces and the second inner surface adjacent to the second electrode respectively, and the other side surface of the second supporting piece is suspended; wherein the diaphragm assembly constituting the second electrode, the partial areas of the two first inner surfaces, the partial area of the second inner surface adjacent to the second electrode, and the partial area of the second support member together form an auxiliary chamber, and the first support member does not enclose the auxiliary chamber.

Optionally, the two diaphragm assemblies, another partial region of the two first inner surfaces, and another partial region of the second support member together form the vibration cavity, and the first support member does not close the vibration cavity.

Optionally, the two diaphragm assemblies, another partial region of the two first inner surfaces, the first support and the second support together form the vibration cavity, and the first support closes the vibration cavity.

Further, the vibration chamber is including being located respectively first sub-chamber and the second sub-chamber of back plate both sides, first sub-chamber with the second sub-chamber passes through fretwork region on the back plate is linked together.

Furthermore, a connecting portion is arranged between the first diaphragm and the second diaphragm, the second diaphragm is fixedly connected with the first diaphragm through the connecting portion, and the projection of the connecting portion on the first diaphragm is located in the middle of the first diaphragm along the thickness direction perpendicular to the substrate.

Further, the first diaphragm, the second diaphragm, and the connecting portion are all made of a conductive medium.

Further, the second diaphragm has a rigidity greater than that of the first diaphragm.

Optionally, the side profile of the second diaphragm is arc-shaped or linear.

Optionally, the second diaphragm is made of the same material as the first diaphragm, and the thickness of the second diaphragm is greater than that of the first diaphragm.

Optionally, the effective sensing area of the second diaphragm is smaller than the effective sensing area of the first diaphragm.

Optionally, at least one through hole is disposed on the first diaphragm and/or the second diaphragm.

According to another aspect of the present invention, there is provided a microphone assembly comprising: the vibration isolator comprises a substrate, a first supporting piece and a second supporting piece fixedly connected with the substrate, and two vibrating diaphragm assemblies, two back plates and a third supporting piece which are positioned between the first supporting piece and the second supporting piece, wherein the two back plates are positioned between the two vibrating diaphragm assemblies, the third supporting piece is positioned between the two back plates so as to separate the two back plates, a cavity is arranged on the substrate, the first supporting piece partially closes one side of the cavity, and the second supporting piece is positioned in the cavity; each diaphragm component comprises a first diaphragm and a second diaphragm which is fixedly connected with the first diaphragm and arranged at intervals, and the second diaphragm is positioned between the first diaphragm and the corresponding back plate;

in the thickness direction of the substrate, one ends of two first diaphragms, two back-plate plates and a third support member in the two diaphragm assemblies are respectively and fixedly connected with the first support member, the other ends of the two first diaphragms, the two back-plate plates and the third support member in the two diaphragm assemblies are respectively and fixedly connected with the second support member, the edges of the two second diaphragms in the two diaphragm assemblies are suspended, and the two first diaphragms, the two back-plate plates, the third support member, the first support member and the second support member jointly divide the cavity into at least one back cavity and two first vibration cavities and two second vibration cavities which are isolated from each other;

one of the two diaphragm assemblies forms a first electrode, the other diaphragm assembly forms a second electrode, one of the two back-pole plates forms a third electrode, the other back-pole plate forms a fourth electrode, the third electrode is located between the first electrode and the third support member, and the fourth electrode is located between the third support member and the second electrode;

the first electrode and the third electrode form a first variable capacitor corresponding to the first vibration cavity, one side of the first electrode, which is far away from the third electrode, is communicated with the back cavity, and one side of the third electrode, which is far away from the first electrode, is isolated from the back cavity;

the second electrode and the fourth electrode form a second variable capacitor corresponding to the second vibration cavity, one side of the fourth electrode, far away from the second electrode, is communicated with the back cavity, and one side of the second electrode, far away from the fourth electrode, is isolated from the back cavity; the fourth electrode is provided with a hollow area, or the fourth electrode and the third electrode are both provided with hollow areas, and the hollow area on the fourth electrode is communicated with the second vibration cavity;

the first variable capacitor and the second variable capacitor constitute a differential capacitor to sense a sound pressure signal.

According to another aspect of the present invention, there is provided a microphone assembly comprising: the vibration isolator comprises a substrate, a first supporting piece and a second supporting piece which are fixedly connected with the substrate, and two vibrating diaphragm assemblies, two back plates and a third supporting piece which are positioned between the first supporting piece and the second supporting piece, wherein the two vibrating diaphragm assemblies and the two back plates are distributed in a staggered manner, a cavity is arranged on the substrate, the first supporting piece partially seals one side of the cavity, and the second supporting piece is positioned in the cavity; each diaphragm component comprises a first diaphragm and a second diaphragm which is fixedly connected with the first diaphragm and arranged at intervals, and the second diaphragm is positioned between the first diaphragm and the corresponding back plate;

in the thickness direction of the substrate, one ends of two first diaphragms, two back plates and a third support member in the two diaphragm assemblies are respectively and fixedly connected with the first support member, the other ends of the two first diaphragms, the two back plates and the third support member in the two diaphragm assemblies are respectively and fixedly connected with the second support member, the edges of the two second diaphragms in the two diaphragm assemblies are suspended, and the two first diaphragms, the two back plates, the third support member, the first support member and the second support member jointly divide the cavity into at least one back cavity and two first vibration cavities and two second vibration cavities which are isolated from each other;

one of the two diaphragm assemblies forms a first electrode, the other diaphragm assembly forms a second electrode, one of the two back-pole plates forms a third electrode, the other back-pole plate forms a fourth electrode, the third electrode is located between the first electrode and the third supporting member, and the fourth electrode is located between the third supporting member and the second electrode;

the second electrode and the fourth electrode form a second variable capacitor corresponding to the second vibration cavity, one side of the second electrode, which is far away from the fourth electrode, is isolated from the back cavity, and one side of the fourth electrode, which is far away from the second electrode, is communicated with the back cavity; the fourth electrode is provided with a hollow area, or the fourth electrode and the third electrode are both provided with hollow areas, and the hollow area on the fourth electrode is communicated with the second vibration cavity;

According to another aspect of the present invention, there is provided a microphone assembly comprising: the vibrating diaphragm assembly comprises a substrate, a first supporting piece and a second supporting piece which are fixedly connected with the substrate, two vibrating diaphragm assemblies and two back pole plates, wherein the two vibrating diaphragm assemblies and the two back pole plates are positioned between the first supporting piece and the second supporting piece and are distributed in a staggered mode; each diaphragm component comprises a first diaphragm and a second diaphragm which is fixedly connected with the first diaphragm and arranged at intervals, and the second diaphragm is positioned between the first diaphragm and the corresponding back plate;

in the thickness direction of the substrate, one ends of two first diaphragms and one ends of two back plates in the two diaphragm assemblies are respectively and fixedly connected with the first supporting piece, the other ends of the two first diaphragms and the other ends of the two back plates in the two diaphragm assemblies are respectively and fixedly connected with the second supporting piece, the edges of the two second diaphragms in the two diaphragm assemblies are suspended, and the two first diaphragms, the two back plates, the first supporting pieces and the second supporting pieces jointly divide the cavity into at least one back cavity and two first vibration cavities and two second vibration cavities which are isolated from each other;

one of the two diaphragm assemblies forms a first electrode, the other diaphragm assembly forms a second electrode, one of the two back-pole plates forms a third electrode, the other back-pole plate forms a fourth electrode, the first electrode is positioned between the third electrode and the fourth electrode, and the fourth electrode is positioned between the first electrode and the second electrode;

According to another aspect of the present invention, there is also provided an electronic device including the microphone assembly of any of the embodiments described above.

The microphone assembly and the electronic equipment provided by the invention not only have higher length-width ratio, increase the application range of products, but also improve the sensitivity and accuracy of electric signal detection of the microphone assembly. Illustratively, the first support body does not enclose the vibration cavity and the auxiliary cavity, and one side surface of the second support body is suspended, so that the microphone assembly is suitable for the bottom-entering sound packaging structure. Illustratively, the first support body seals the vibration cavity, does not seal the auxiliary cavity, and one side of the second support body is suspended, so that the microphone assembly is suitable for the packaging structure of bottom sound and top sound. Meanwhile, the first vibration cavity and the second vibration cavity are communicated through the hollow area, so that the first variable capacitor and the second variable capacitor form a differential capacitor, noise interference is avoided, and product performance is improved.

Further, every vibrating diaphragm subassembly all includes first vibrating diaphragm and with first vibrating diaphragm fixed connection and the second vibrating diaphragm that the interval set up, produce the linkage effect between first vibrating diaphragm and the second vibrating diaphragm, under the effect of the sound energy or the acoustic pressure load of incidenting on first vibrating diaphragm one side, the vibration deformation through first vibrating diaphragm can drive the direction removal of second vibrating diaphragm towards the back plate, thereby lead to the distance between second vibrating diaphragm and the back plate to change, and then produce corresponding electric capacity and change, in order to realize the acoustoelectric conversion.

Further, because the edge of the second diaphragm is suspended, the second diaphragm does not need to be deformed by the vibration of the second diaphragm, but is pushed to move towards the direction of the back plate by the force generated by the vibration deformation of the first diaphragm. The second diaphragm almost translates towards the direction of the back plate, and finally the distance between the second diaphragm and the back plate gradually decreases, so that the capacitance variation between the second diaphragm and the back plate can be obviously improved, the output electric signal is increased, and the sensitivity and the accuracy of the electric signal detection of the microphone assembly are improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be 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 application, and it is obvious for those skilled in the art to obtain other embodiments based on these drawings without creative efforts.

Fig. 1A is a perspective view of a microphone assembly according to an embodiment of the invention.

FIG. 1B is a schematic diagram of the structure of the substrate provided in the embodiment of FIG. 1A.

Fig. 1C is a schematic cross-sectional structural view of the microphone assembly provided in the embodiment of fig. 1A.

Fig. 1D is a schematic top view of the microphone assembly of fig. 1A with the first supporting element removed.

Fig. 1E is a schematic side view of a microphone assembly provided in the embodiment of fig. 1A.

Fig. 1F is a schematic top view of another microphone assembly provided in the embodiment of fig. 1A, with a first supporting member removed.

Fig. 2 is a schematic side view of another microphone assembly provided in the embodiment of fig. 1A.

Fig. 3 is a side view of another microphone assembly provided in the embodiment of fig. 1A.

Fig. 4A is a schematic structural diagram of a microphone assembly according to another embodiment of the present invention.

Fig. 4B is a side view of another microphone assembly provided in the embodiment of fig. 4A.

Fig. 5A is a schematic perspective view of a microphone assembly according to another embodiment of the invention.

Fig. 5B is a schematic top view of the microphone assembly of fig. 5A with the first support removed.

Fig. 6A is a schematic perspective view of a microphone assembly according to another embodiment of the invention.

Fig. 6B is a schematic top view of the microphone assembly of fig. 6A with the first support removed.

Fig. 7A is a perspective view of a microphone assembly according to another embodiment of the invention.

Fig. 7B is a schematic top view of the microphone assembly of fig. 7A with the first support removed.

Detailed Description

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The embodiment of the invention provides a microphone component which is a core component of an MEMS (micro-electromechanical system) microphone and can be applied to electronic equipment with a sound acquisition function, such as a smart phone, a tablet personal computer, a recording pen, a hearing aid, vehicle-mounted equipment and the like. The embodiments of the present invention are not limited to the above application scenarios.

Example one

Fig. 1A is a schematic perspective view of a microphone assembly according to an embodiment of the present invention, fig. 1B is a schematic structural view of a substrate provided in the embodiment of fig. 1A, fig. 1C is a schematic cross-sectional structural view of the microphone assembly provided in the embodiment of fig. 1A, fig. 1D is a schematic top-view structural view of a portion of the microphone assembly in the embodiment of fig. 1A with a first supporting member removed, and fig. 1E is a schematic side-view structural view of the microphone assembly provided in the embodiment of fig. 1A.

Referring to fig. 1A to 1E, a microphone assembly 1000 according to an embodiment of the present invention includes a substrate 10, a first supporting member 20 and a second supporting member 30 fixedly connected to the substrate 10, and two diaphragm assemblies and a back plate 40 located between the first supporting member 20 and the second supporting member 30, where the back plate 40 has a hollow area 401 and is located between the two diaphragm assemblies, a cavity 110 is disposed on the substrate 10, the first supporting member 20 partially encloses one side of the cavity 110, and the second supporting member 30 is located in the cavity 110; each diaphragm component comprises a first diaphragm 511 and a second diaphragm 512 fixedly connected with the first diaphragm 511 and arranged at an interval, the second diaphragm 512 is located between the first diaphragm 511 and the back plate 40, in the thickness direction of the substrate 10, one end of the first diaphragm 511 and one end of the back plate 40 are respectively and fixedly connected with the first support member 20, the other end of the first diaphragm 511 and the other end of the back plate 40 are respectively and fixedly connected with the second support member 30, the edge of the second diaphragm 512 is suspended, and the first diaphragm 511, the back plate 40, the first support member 20 and the second support member 30 jointly divide the cavity 110 into at least a vibration cavity 80 and a back cavity 60; one of the two diaphragm assemblies forms a first electrode 510, the other diaphragm assembly forms a second electrode 520, the back plate 40 forms a third electrode 410, one side of the first electrode 510, which is far away from the back plate 40, is communicated with the back cavity 60 and forms a first variable capacitor with the third electrode 410, one side of the second electrode 520, which is far away from the back plate 40, is isolated from the back cavity 60 and forms a second variable capacitor with the third electrode, and the first variable capacitor and the second variable capacitor form a differential capacitor to sense a sound pressure signal.

It should be noted that, in the embodiment of the present invention, each of the second diaphragms 512 in the two diaphragm assemblies has a certain predetermined gap with the back plate 40. For example, the gap d is 2 to 3um.

For example, in the embodiment of the present invention, the first support 20 and the second support 30 are both made of an electrically insulating material, such as SiO2 material.

The microphone assembly and the electronic equipment provided by the embodiment of the invention not only can obviously improve the signal-to-noise ratio of the microphone, but also have small volume. Compared with a structure that the diaphragm assembly and the back plate are arranged perpendicular to the thickness direction of the substrate, the microphone assembly in the embodiment of the invention can have a higher length-width ratio so as to be suitable for products with a high length-width ratio.

Illustratively, in this embodiment, the cavity 110 has two first inner surfaces 1101 perpendicular to the two diaphragm assemblies and the back plate 40 and two second inner surfaces 1102 parallel to the two diaphragm assemblies and the back plate 40, three sides of the second support 30 are fixedly connected to the two first inner surfaces 1101, the second inner surface 1102 adjacent to the second electrode 520, and the other side is suspended. One side of the second supporting member 30 is suspended, so that one of the two diaphragm assemblies is communicated with the back cavity 60, and external sound pressure can act on the diaphragm assembly, so that the microphone assembly with bottom-in sound can be applied.

Wherein the diaphragm assembly constituting the second electrode 520, the partial areas of the two first inner surfaces 1101, the partial area of the second inner surface 1102 of the diaphragm assembly immediately adjacent to the second electrode 520 and the partial area of the second support 30 together form the auxiliary chamber 70, and the first support 20 does not enclose the auxiliary chamber 70. At this time, the auxiliary chamber 70 serves to provide a deformation space for the diaphragm assembly constituting the second electrode 520.

In this embodiment, the two diaphragm assemblies, another partial region of the two first inner surfaces 1101, and another partial region of the second support 30 together form the vibration cavity 80, and the first support 20 does not enclose the vibration cavity 80.

Illustratively, in the present embodiment, the vibration chamber 80 includes a first sub-chamber 81 and a second sub-chamber 82 respectively located at two sides of the back plate 40, and the first sub-chamber 81 and the second sub-chamber 82 are communicated through a hollow area 401 on the back plate 40. The first sub-cavity 81 is communicated with the second sub-cavity 82 through the hollow-out area 401 to transmit external sound pressure to the two diaphragm assemblies, and vibration of the two diaphragm assemblies is caused respectively, wherein the distance between the diaphragm assembly forming the first electrode 510 and the back plate 40 forming the third electrode 410 is reduced, the distance between the diaphragm assembly forming the second electrode 520 and the back plate 40 forming the third electrode 410 is increased, so that the first variable capacitor is increased, the second variable capacitor is reduced, the first variable capacitor and the second variable capacitor form a differential capacitor, the controller processes the two signals and outputs a differential electric signal, and therefore sensitivity of the microphone assembly is improved.

Specifically, as shown in fig. 1C, when the sound pressure load during normal operation and the blowing load during abnormal operation are applied to the first diaphragm 511 of the diaphragm assembly constituting the first electrode 510 from the bottom of the microphone assembly through the back cavity 60, since the edge of the second diaphragm 512 of the diaphragm assembly constituting the first electrode 510 is suspended (without fixed support), the second diaphragm 512 of the diaphragm assembly constituting the first electrode 510 does not need to be deformed by its own vibration, but the second diaphragm 512 of the diaphragm assembly constituting the first electrode 510 is pushed to move toward the direction of the back plate 40 based on the force generated by the vibration deformation of the first diaphragm 511 of the diaphragm assembly constituting the first electrode 510. Here, the second diaphragm 512 of the diaphragm assembly forming the first electrode 510 is translated almost toward the back plate 40, and finally, the distance between the second diaphragm 512 of the diaphragm assembly forming the first electrode 510 and the back plate 40 is gradually decreased, so that the capacitance variation between the second diaphragm 512 of the diaphragm assembly forming the first electrode 510 and the back plate 40 can be significantly increased to increase the output electric signal, thereby improving the sensitivity of the microphone assembly 1000.

Further, when the sound pressure is transmitted through the hollow area 401 on the back plate 40 and acts on the second diaphragm 512 of the other diaphragm assembly constituting the second electrode 520, because the edge of the second diaphragm 512 of the other diaphragm assembly constituting the second electrode 520 is suspended (without fixed support), at this time, the distance between the area other than the middle of the second diaphragm 512 of the other diaphragm assembly constituting the second electrode 520 and the back plate 40 may be changed by the vibration deformation of the second diaphragm 512 of the other diaphragm assembly constituting the second electrode 520, and the capacitance change of the corresponding second variable capacitance is generated, so that the capacitance change amount between the second diaphragm 512 of the other diaphragm assembly constituting the second electrode 520 and the back plate 40 may be significantly increased, so as to increase the output electrical signal, and thereby improve the sensitivity of the microphone assembly 1000.

In this embodiment, the first variable capacitor and the second variable capacitor together form a differential capacitor to realize the acoustic-electric conversion.

Exemplarily, in this embodiment, a connection portion 513 is disposed between the first diaphragm 511 and the second diaphragm 512 on the two diaphragm assemblies, and the second diaphragm 512 is fixedly connected to the first diaphragm 511 through the connection portion 513, wherein, in a thickness direction perpendicular to the substrate 10, a projection of the connection portion 513 on the first diaphragm 511 is located in a middle of the first diaphragm 511. Here, since the region where the deformation amount of the first diaphragm 511 is large is often the central region of the first diaphragm 511, the connection part 513 is disposed in the middle of the first diaphragm 511, so that the moving distance of the second diaphragm 512 is maximized, and the distance variation between the second diaphragm 512 and the back plate 40 is increased.

Further, the first diaphragm 511, the second diaphragm 512, and the connecting portion 513 are each formed of a conductive medium. The conductive medium is, for example, polysilicon, so that the transmission of electrical signals within each diaphragm assembly is better achieved.

Optionally, the second diaphragm 512 has a stiffness greater than that of the first diaphragm 511. Stiffness refers to the ability of a material or structure to resist elastic deformation when subjected to a force. In an embodiment, the first diaphragm 511 with smaller rigidity can be deformed more easily by sound pressure load, so as to drive the second diaphragm 512 to move toward the back plate 40; moreover, because the edge of the second diaphragm 512 is suspended (without fixed support), the second diaphragm 512 with higher rigidity keeps flatness when moving, so that the second diaphragm 512 can move uniformly toward the direction of the back plate 40 under the action of the pushing force generated by the deformation of the first diaphragm 511, so as to increase the capacitance variation between the second diaphragm 512 and the back plate 40.

For example, as shown in fig. 1E, in the embodiment of the present invention, the side profile of the second diaphragm 512 is in a shape of a "straight line", and the size d of the gap between the second diaphragm 512 and the back plate 40 at each position can be kept relatively balanced, so that the second diaphragm 512 with the side profile in the shape of a "straight line" is pressed on an almost straight line, and therefore, the size of the capacitance change between the second diaphragm 512 and the back plate 40 can be significantly improved, thereby effectively improving the sensitivity and accuracy of the microphone assembly.

Optionally, the second diaphragm 512 and the first diaphragm 511 are made of the same material, and the thickness of the second diaphragm 512 is greater than that of the first diaphragm 511, as can be seen from the foregoing, the second diaphragm 512 is fixed on the first diaphragm 511 through the connecting portion 513, and the edge of the second diaphragm 512 is suspended, so that the thicker the thickness, the more easily the flatness of the second diaphragm 512 is maintained, and the second diaphragm 512 is not easily shaken during the moving process.

Optionally, the effective sensing area of the second diaphragm 512 is smaller than the effective sensing area of the first diaphragm 511, and it should be noted that the effective sensing area of the second diaphragm 512 is the facing area of the second diaphragm 512 and the back-plate 40, and the effective sensing area of the first diaphragm 511 is the facing area of the first diaphragm 511 and the back-plate 40. As can be seen from the foregoing, the second diaphragm 512 is fixed on the first diaphragm 511 by the connecting portion 513, and because the edge of the second diaphragm 512 is suspended, the smaller the effective sensing area (size) of the second diaphragm 512 is, the easier the flatness of the second diaphragm 512 is to be maintained, and the second diaphragm 512 is not easy to shake during moving.

Optionally, at least one through hole is disposed on the first diaphragm 511 and/or the second diaphragm 512, so as to reduce squeeze film damping on the diaphragm assembly and prevent film breakage.

Further, in the present embodiment, the microphone assembly further includes a first electrode extraction passage 5101 electrically connected to the first electrode 510, a second electrode extraction passage 5201 electrically connected to the second electrode, and a third electrode extraction passage 4101 electrically connected to the third electrode 410.

Fig. 1F is a schematic top view of another microphone assembly provided in the embodiment of fig. 1A, with a first supporting element removed.

As shown in fig. 1D and fig. 1F, for example, in the present embodiment, the hollow area 401 on the back plate 40 includes a plurality of rectangular sub-areas 4011. It should be noted that the sizes of the plurality of rectangular sub-regions 4011 and the distance between two adjacent rectangular sub-regions 4011 may be set as needed while ensuring the rigidity of the back plate 40. For example, as shown in fig. 1D, the plurality of rectangular sub-regions 4011 are equally sized and equally spaced. For example, as shown in fig. 1F, the rectangular sub-regions 4011 have different sizes and are distributed at different intervals, and the interval of the rectangular sub-region 4011 located in the middle of the backplate 40 is greater than the interval of the rectangular sub-regions 4011 located at the edge of the backplate 40, so that noise of the microphone during operation can be effectively reduced, and the signal-to-noise ratio of the product can be improved.

In this embodiment, the effective area of the backplate 40 is smaller than the effective area of the diaphragm assembly. By setting the effective area of the back plate 40 smaller than that of the diaphragm assembly, parasitic capacitance can be reduced, thereby improving sensitivity.

Example two

Fig. 2 is a schematic side view of another microphone assembly provided in the embodiment of fig. 1A, and fig. 3 is a schematic side view of another microphone assembly provided in the embodiment of fig. 1A.

As shown in fig. 2 and 3, the present embodiment exemplarily differs from fig. 1E in that: and the side profile of the second diaphragm 512 fixedly connected with the first diaphragm 511 is in the shape of a circular arc.

For example, as shown in fig. 2, in the present embodiment, the side surfaces of the two second diaphragms 512 of the two diaphragm assemblies are respectively concave toward the back plate 40, that is, the gap between each second diaphragm 512 and the back plate 40 gradually increases along the position where the middle portion of each second diaphragm 512 is directed to the edge thereof; so that one of the second diaphragms 512 can improve noise during the process of moving toward the back plate 40, thereby improving the signal-to-noise ratio of the microphone assembly.

Illustratively, as shown in fig. 3, in the present embodiment, the side surfaces of the two second diaphragms 512 of the two diaphragm assemblies are respectively convex toward the back plate 40, that is, the gap between the second diaphragm 512 and the back plate 40 gradually decreases along the position where the middle portion of each second diaphragm 512 is directed to the edge thereof; so that one of the second diaphragms 512 can improve noise during the process of moving toward the back plate 40, thereby improving the signal-to-noise ratio of the microphone assembly. The reason is that the second diaphragm 512 is in a convex arc shape, and when the second diaphragm 512 is driven by the first diaphragm 511 to move, the second diaphragm 512 has small motion resistance, large displacement of movement, large capacitance change, and high product sensitivity, so that the signal-to-noise ratio is higher.

EXAMPLE III

Fig. 4A is a schematic structural diagram of a microphone assembly according to another embodiment of the present invention, and fig. 4B is a schematic structural diagram of a side view of the microphone assembly provided in the embodiment of fig. 4A.

As shown in fig. 4A and 4B, fig. 4A is different from fig. 1A in that: one end of each of the two diaphragm assemblies and the back plate 40 is fixedly connected to the first support 20, the two diaphragm assemblies, another partial region of the two first inner surfaces, the first support 20 and the second support 30 jointly form a vibration cavity 80, and the first support 20 closes the vibration cavity 80. The vibration cavity 80 is sealed by the first support member 20, the vibration cavity 80 is not communicated with the external environment, and the back cavity 60 and the auxiliary cavity 70 are both communicated with the external environment, so that the microphone assembly can be suitable for a bottom-in sound packaging structure and a front-in sound packaging structure. On the one hand, the auxiliary chamber 70 serves to provide a deformation space for the diaphragm when sound waves enter the back chamber 60 and then act on the diaphragm, and on the other hand, sound waves can also enter the auxiliary chamber 70, and in this case, the auxiliary chamber 70 serves as a forward sound.

Example four

Fig. 5A is a perspective view of a microphone assembly according to another embodiment of the invention, and fig. 5B is a partial top view of the microphone assembly according to the embodiment of fig. 5A with a first supporting member removed.

As shown in fig. 5A-5B, the present embodiment further provides a microphone assembly, which includes a substrate 10, a first supporting member 20 and a second supporting member 30 fixedly connected to the substrate 10, and two diaphragm assemblies located between the first supporting member 20 and the second supporting member 30, two back-plates and a third supporting member 90, wherein the two back-plates are located between the two diaphragm assemblies and the third supporting member 90 is located between the two back-plates to isolate the two back-plates, a cavity is provided on the substrate 10, the first supporting member 20 partially encloses one side of the cavity, and the second supporting member 30 is located in the cavity; each diaphragm component comprises a first diaphragm 511 and a second diaphragm 512 fixedly connected with the first diaphragm 511 and arranged at intervals, and the second diaphragm 512 is positioned between the first diaphragm 511 and a back plate corresponding to the first diaphragm 511;

in the thickness direction of the substrate 10, one end of each of two first diaphragms 511, two back plates, and a third support 90 in the two diaphragm assemblies is respectively and fixedly connected to the first support 20, the other end of each of the two first diaphragms 511, two back plates, and a third support 90 in the two diaphragm assemblies is respectively and fixedly connected to the second support 30, the edges of the two second diaphragms 512 in the two diaphragm assemblies are suspended, and the two first diaphragms 511, two back plates, the third support 90, the first supports 20, and the second support 30 jointly divide the cavity into at least one back cavity 60, and two first vibration cavities 810 and two second vibration cavities 820 that are isolated from each other;

wherein one of the two diaphragm assemblies constitutes a first electrode 510, the other of the two diaphragm assemblies constitutes a second electrode 520, one of the two back-plate plates constitutes a third electrode 410, the other of the two back-plate plates constitutes a fourth electrode 420, the third electrode 410 is located between the first electrode 510 and the third supporting member 90, and the fourth electrode 420 is located between the third supporting member 90 and the second electrode 520;

the first electrode 510 and the third electrode 410 form a first variable capacitance corresponding to the first vibration cavity 810, and the side of the first electrode 510 away from the third electrode 410 is communicated with the back cavity 60, and the side of the third electrode 410 away from the first electrode 510 is isolated from the back cavity 60;

the second electrode 520 and the fourth electrode 420 form a second variable capacitance corresponding to the second vibration cavity 820, and one side of the fourth electrode 420 away from the second electrode 520 is communicated with the back cavity 60, and one side of the second electrode 520 away from the fourth electrode 420 is isolated from the back cavity 60; the fourth electrode 420 has a hollow area 401, or both the fourth electrode 420 and the third electrode 410 have hollow areas 401, and the hollow areas 401 on the fourth electrode 420 are communicated with the second vibration cavity 820;

Exemplarily, in this embodiment, a connection portion 513 is disposed between the first diaphragm 511 and the second diaphragm 512 on the two diaphragm assemblies, and the second diaphragm 512 is fixedly connected to the first diaphragm 511 through the connection portion 513, wherein, in a thickness direction perpendicular to the substrate 10, a projection of the connection portion 513 on the first diaphragm 511 is located in a middle of the first diaphragm 511. Here, since the region where the deformation amount of the first diaphragm 511 is large is often the central region of the first diaphragm 511, the connection part 513 is disposed in the middle of the first diaphragm 511, so that the moving distance of the second diaphragm 512 is maximized, and the distance variation between the second diaphragm 512 and the corresponding back plate is increased.

Optionally, the second diaphragm 512 has a stiffness greater than that of the first diaphragm 511. Stiffness refers to the ability of a material or structure to resist elastic deformation when subjected to a force. In an embodiment, the first diaphragm 511 with smaller rigidity can be deformed more easily by sound pressure load, so as to drive the second diaphragm 512 to move toward the corresponding back plate; moreover, because the edge of the second diaphragm 512 is suspended (without fixed support), the second diaphragm 512 with higher rigidity keeps flatness when moving, so that the second diaphragm 512 can move uniformly toward the direction of the corresponding back plate under the action of the pushing force generated by the deformation of the first diaphragm 511, so as to increase the capacitance variation between the second diaphragm 512 and the corresponding back plate.

Optionally, the effective sensing area of the second diaphragm 512 is smaller than the effective sensing area of the first diaphragm 511, and it should be noted that the effective sensing area of the second diaphragm 512 is the facing area of the second diaphragm 512 and the corresponding back plate, and the effective sensing area of the first diaphragm 511 is the facing area of the first diaphragm 511 and the corresponding back plate. As can be seen from the foregoing, the second diaphragm 512 is fixed on the first diaphragm 511 by the connecting portion 513, and because the edge of the second diaphragm 512 is suspended, the smaller the effective sensing area (size) of the second diaphragm 512 is, the easier the flatness of the second diaphragm 512 is to be maintained, and the second diaphragm 512 is not easy to shake during moving.

EXAMPLE five

Fig. 6A is a schematic perspective view of a microphone assembly according to another embodiment of the present invention, and fig. 6B is a schematic top view of the microphone assembly according to the embodiment of fig. 6A with a first supporting element removed.

As shown in fig. 6A-6B, the present embodiment further provides a microphone assembly, where the microphone assembly includes a substrate 10, a first supporting member 20 and a second supporting member 30 fixedly connected to the substrate 10, and two diaphragm assemblies, two back plates and a third supporting member 90 located between the first supporting member 20 and the second supporting member 30, where the two diaphragm assemblies and the two back plates are distributed alternately, a cavity is disposed on the substrate 10, the first supporting member 20 partially encloses one side of the cavity, and the second supporting member 30 is located in the cavity; each diaphragm component comprises a first diaphragm 511 and a second diaphragm 512 fixedly connected with the first diaphragm 511 and arranged at intervals, and the second diaphragm 512 is positioned between the first diaphragm 511 and a back plate corresponding to the first diaphragm 511;

the second electrode 520 and the fourth electrode 420 form a second variable capacitance corresponding to the second vibration cavity 820, and the side of the second electrode 520 away from the fourth electrode 420 is isolated from the back cavity 60, and the side of the fourth electrode 420 away from the second electrode 520 is communicated with the back cavity 60; the fourth electrode 420 has a hollow area 401, or both the fourth electrode 420 and the third electrode 410 have hollow areas 401, and the hollow areas 401 on the fourth electrode 420 are communicated with the second vibration cavity 820;

Further, the first diaphragm 511, the second diaphragm 512, and the connecting portion 513 are each constituted by a conductive medium. The conductive medium is, for example, polysilicon, so that the transmission of electrical signals can be better achieved within each diaphragm assembly.

EXAMPLE six

Fig. 7A is a schematic perspective view of a microphone assembly according to another embodiment of the invention, and fig. 7B is a schematic top view of the microphone assembly according to the embodiment of fig. 7A with a first supporting element removed.

As shown in fig. 7A-7B, the present embodiment further provides a microphone assembly, where the microphone assembly includes a substrate 10, a first supporting member 20 and a second supporting member 30 fixedly connected to the substrate 10, and two diaphragm assemblies and two back plates located between the first supporting member 20 and the second supporting member 30, the two diaphragm assemblies and the two back plates are distributed alternately, a cavity is disposed on the substrate 10, the first supporting member 20 partially encloses one side of the cavity, and the second supporting member 30 is located in the cavity; each diaphragm component comprises a first diaphragm 511 and a second diaphragm 512 fixedly connected with the first diaphragm 511 and arranged at intervals, and the second diaphragm 512 is located between the first diaphragm 511 and a back plate corresponding to the first diaphragm 511;

in the thickness direction of the substrate 10, one ends of two first diaphragms 511 and two back plates in two diaphragm assemblies are respectively and fixedly connected with the first supporting member 20, the other ends of the two first diaphragms 511 and the two back plates in the two diaphragm assemblies are respectively and fixedly connected with the second supporting member 30, the edges of two second diaphragms 512 in the two diaphragm assemblies are suspended, and the two first diaphragms 511, the two back plates, the first supporting member 20 and the second supporting member 30 jointly divide the cavity into at least one back cavity 60 and two first vibration cavities 810 and two second vibration cavities 820 which are isolated from each other;

one of the two diaphragm assemblies forms a first electrode 510, the other diaphragm assembly forms a second electrode 520, one of the two back-plate plates forms a third electrode 410, the other back-plate forms a fourth electrode 420, the first electrode 510 is located between the third electrode 410 and the fourth electrode 420, and the fourth electrode 420 is located between the first electrode 510 and the second electrode 520;

the first variable capacitor and the second variable capacitor constitute a differential capacitor to sense a sound pressure signal. Exemplarily, in this embodiment, a connection portion 513 is disposed between the first diaphragm 511 and the second diaphragm 512 on the two diaphragm assemblies, and the second diaphragm 512 is fixedly connected to the first diaphragm 511 through the connection portion 513, wherein, in a thickness direction perpendicular to the substrate 10, a projection of the connection portion 513 on the first diaphragm 511 is located in a middle of the first diaphragm 511. Here, since the region where the deformation amount of the first diaphragm 511 is large is often the central region of the first diaphragm 511, the connection part 513 is disposed in the middle of the first diaphragm 511, so that the moving distance of the second diaphragm 512 is maximized, and the distance variation between the second diaphragm 512 and the corresponding back plate is increased.

Further, the first diaphragm 511, the second diaphragm 512, and the connecting portion 513 are each formed of a conductive medium. The conductive medium is, for example, polysilicon, so that the transmission of electrical signals can be better achieved within each diaphragm assembly.

Optionally, the second diaphragm 512 has a stiffness greater than that of the first diaphragm 511. Stiffness refers to the ability of a material or structure to resist elastic deformation when subjected to a force. In an embodiment, the first diaphragm 511 with smaller rigidity can be deformed more easily by sound pressure load, so as to drive the second diaphragm 512 to move toward the corresponding back plate; moreover, since the edge of the second diaphragm 512 is suspended (without fixed support), the second diaphragm 512 with higher rigidity keeps flatness when moving, so that the second diaphragm 512 can move uniformly toward the direction of the corresponding back plate under the action of the pushing force generated by the deformation of the first diaphragm 511, so as to increase the capacitance variation between the second diaphragm 512 and the corresponding back plate.

Optionally, the effective sensing area of the second diaphragm 512 is smaller than the effective sensing area of the first diaphragm 511, and it should be noted that the effective sensing area of the second diaphragm 512 is the facing area of the second diaphragm 512 and the corresponding back-plate, and the effective sensing area of the first diaphragm 511 is the facing area of the first diaphragm 511 and the corresponding back-plate. As can be seen from the foregoing, the second diaphragm 512 is fixed on the first diaphragm 511 through the connecting portion 513, and since the edge of the second diaphragm 512 is suspended, the smaller the effective sensing area (size) of the second diaphragm 512 is, the easier the flatness of the second diaphragm 512 is to be maintained, and the second diaphragm 512 is not easy to shake during moving.

At least one embodiment of the invention also provides an electronic device, which comprises the microphone assembly as described in any one of the above embodiments.

In the embodiments of the present application, unless otherwise specified or conflicting with respect to logic, terms or descriptions in different embodiments have consistency and may be mutually cited, and technical features in different embodiments may be combined to form a new embodiment according to their inherent logic relationship. In this application, "at least one" means one or more, "a plurality" means two or more.

It is to be understood that the various numerical references referred to in the embodiments of the present application are merely for convenience of description and distinction and are not intended to limit the scope of the embodiments of the present application. The sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of the processes should be determined by their functions and inherent logic.

The microphone assembly and the electronic device provided in the embodiments of the present application are described in detail above, and the principles and embodiments of the present application are described herein by applying specific examples, and the description of the embodiments above is only used to help understand the method and the core idea of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, the specific implementation manner and the application scope may be changed, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A microphone assembly, which is characterized by comprising a substrate (10), a first supporting part (20) and a second supporting part (30) fixedly connected with the substrate (10), and two diaphragm assemblies and a back plate (40) positioned between the first supporting part (20) and the second supporting part (30), wherein the back plate (40) has a hollow area and is positioned between the two diaphragm assemblies, a cavity is arranged on the substrate (10), the first supporting part (20) partially closes one side of the cavity, and the second supporting part (30) is positioned in the cavity;

each diaphragm assembly comprises a first diaphragm (511) and a second diaphragm (512) which is fixedly connected with the first diaphragm (511) and arranged at an interval, the second diaphragm (512) is positioned between the first diaphragm (511) and the back plate (40), in the thickness direction of the substrate (10), one end of the first diaphragm (511) and one end of the back plate (40) are respectively and fixedly connected with the first supporting piece (20), the other end of the first diaphragm (511) and the other end of the back plate (40) are respectively and fixedly connected with the second supporting piece (30), the edge of the second diaphragm (512) is suspended, and the first diaphragm (511), the back plate (40), the first supporting piece (20) and the second supporting piece (30) jointly divide the cavity into at least a vibration cavity (80) and a back cavity (60);

one of the two diaphragm assemblies forms a first electrode (510), the other diaphragm assembly forms a second electrode (520), the back plate (40) forms a third electrode (410), the first electrode (510) and the second electrode (520) form a first variable capacitor, the third electrode (410) and the second electrode (520) form a second variable capacitor, one side of the first electrode (510) far away from the back plate (40) is communicated with the back cavity (60), one side of the second electrode (520) far away from the back plate (40) is isolated from the back cavity (60), and the first variable capacitor and the second variable capacitor form a differential capacitor to sense a sound pressure signal.

2. The microphone assembly of claim 1,

the cavity is provided with two first inner surfaces (1101) perpendicular to the two diaphragm assemblies and the back plate (40) and two second inner surfaces (1102) parallel to the two diaphragm assemblies and the back plate (40), three sides of the second supporting piece (30) are fixedly connected with the two first inner surfaces (1101) and the second inner surface (1102) adjacent to the second electrode (520), and the other side is suspended;

wherein a diaphragm assembly constituting the second electrode (520), a partial area of both of the first inner surfaces (1101), a partial area of the second inner surface (1102) next to the second electrode (520) and a partial area of the second support (30) together form an auxiliary cavity (70), and the first support (20) does not enclose the auxiliary cavity (70).

3. A microphone assembly according to claim 2, characterized in that the two diaphragm assemblies, a further partial region of the two first inner surfaces (1101), and a further partial region of the second support (30) together form the vibration chamber (80), and the first support (20) does not enclose the vibration chamber (80).

4. A microphone assembly according to claim 2, characterized in that the two diaphragm assemblies, the other partial areas of the two first inner surfaces (1101), the first support (20) and the second support (30) together form the vibration chamber (80), and the first support (20) encloses the vibration chamber (80).

5. The microphone assembly according to any one of claims 1-4, wherein the vibration chamber (80) comprises a first sub-chamber (81) and a second sub-chamber (82) respectively located on both sides of the backplate (40), and the first sub-chamber (81) and the second sub-chamber (82) are communicated through a hollowed-out region (401) on the backplate (40).

6. The microphone assembly of claim 5,

a connecting part (513) is arranged between the first diaphragm (511) and the second diaphragm (512), the second diaphragm (512) is fixedly connected with the first diaphragm (511) through the connecting part (513), and the projection of the connecting part (513) on the first diaphragm (511) is positioned in the middle of the first diaphragm (511) along the thickness direction perpendicular to the substrate (10).

7. The microphone assembly of claim 6,

the first diaphragm (511), the second diaphragm (512), and the connecting portion (513) are each formed of a conductive medium.

8. The microphone assembly of claim 7,

the second diaphragm (512) has a rigidity larger than that of the first diaphragm (511).

9. The microphone assembly of claim 7,

the side profile of the second diaphragm (512) is arc-shaped or linear.

10. The microphone assembly of claim 7,

the second diaphragm (512) and the first diaphragm (511) are made of the same material, and the thickness of the second diaphragm (512) is larger than that of the first diaphragm (511).

11. The microphone assembly of claim 7,

the effective sensing area of the second diaphragm (512) is smaller than the effective sensing area of the first diaphragm (511).

12. The microphone assembly of claim 5,

at least one through hole is arranged on the first vibrating diaphragm (511) and/or the second vibrating diaphragm (512).

13. A microphone assembly, comprising a base (10), a first support (20) and a second support (30) fixedly connected to the base (10), and two diaphragm assemblies between the first support (20) and the second support (30), two back plates between the two diaphragm assemblies and a third support (90) between the two back plates to isolate the two back plates, a cavity being provided in the base (10), the first support (20) partially closing one side of the cavity, the second support (30) being located in the cavity; each diaphragm assembly comprises a first diaphragm (511) and a second diaphragm (512) fixedly connected with the first diaphragm (511) and arranged at intervals, and the second diaphragm (512) is positioned between the first diaphragm (511) and the corresponding back plate;

in the thickness direction of the substrate (10), one end of each of two first diaphragms (511), two back plates and a third support member (90) of the two diaphragm assemblies is fixedly connected with the first support member (20), the other end of each of the two first diaphragms (511), the two back plates and the third support member (90) of the two diaphragm assemblies is fixedly connected with the second support member (30), the edges of two second diaphragms (512) of the two diaphragm assemblies are suspended, and the two first diaphragms (511), the two back plates, the third support member (90), the first support member (20) and the second support member (30) jointly divide the cavity into at least one back cavity (60) and two first vibration cavities (810) and a second vibration cavity (820) which are isolated from each other;

wherein one of the two diaphragm assemblies constitutes a first electrode (510), the other of the two diaphragm assemblies constitutes a second electrode (520), one of the two backplate plates constitutes a third electrode (410), the other of the two backplate plates constitutes a fourth electrode (420), the third electrode (410) is located between the first electrode (510) and the third support member (90), and the fourth electrode (420) is located between the third support member (90) and the second electrode (520);

the first electrode (510) and the third electrode (410) form a first variable capacitance corresponding to the first vibration cavity (810), and the side of the first electrode (510) far away from the third electrode (410) is communicated with the back cavity (60), and the side of the third electrode (410) far away from the first electrode (510) is isolated from the back cavity (60);

the second electrode (520) and the fourth electrode (420) form a second variable capacitance corresponding to the second vibration cavity (820), and the side of the fourth electrode (420) far away from the second electrode (520) is communicated with the back cavity (60), and the side of the second electrode (520) far away from the fourth electrode (420) is isolated from the back cavity (60); wherein the fourth electrode (420) is provided with a hollow area (401), or the fourth electrode (420) and the third electrode (410) are both provided with hollow areas, and the hollow area (401) on the fourth electrode (420) is communicated with the second vibration cavity (820);

14. The microphone assembly of claim 13,

15. The microphone assembly of claim 14,

16. The microphone assembly of claim 15,

the second diaphragm (512) has a stiffness greater than that of the first diaphragm (511).

17. The microphone assembly of claim 15,

18. The microphone assembly of claim 15,

19. A microphone assembly, comprising a base (10), a first supporting member (20) and a second supporting member (30) fixedly connected to the base (10), and two diaphragm assemblies, two back-plates and a third supporting member (90) located between the first supporting member (20) and the second supporting member (30), wherein the two diaphragm assemblies and the two back-plates are distributed alternately, a cavity is provided on the base (10), the first supporting member (20) partially encloses one side of the cavity, and the second supporting member (30) is located in the cavity; each diaphragm assembly comprises a first diaphragm (511) and a second diaphragm (512) fixedly connected with the first diaphragm (511) and arranged at intervals, and the second diaphragm (512) is positioned between the first diaphragm (511) and the corresponding back plate;

the second electrode (520) and the fourth electrode (420) form a second variable capacitance corresponding to the second vibration cavity (820), and the side of the second electrode (520) far away from the fourth electrode (420) is isolated from the back cavity (60), and the side of the fourth electrode (420) far away from the second electrode (520) is communicated with the back cavity (60); wherein the fourth electrode (420) is provided with a hollow area (401), or the fourth electrode (420) and the third electrode (410) are both provided with hollow areas (401), and the hollow areas (401) on the fourth electrode (420) are communicated with the second vibration cavity (820);

20. The microphone assembly of claim 19,

21. The microphone assembly of claim 20,

22. The microphone assembly of claim 21,

23. The microphone assembly of claim 21,

24. The microphone assembly of claim 21,

25. A microphone assembly is characterized by comprising a substrate (10), a first supporting piece (20) and a second supporting piece (30) which are fixedly connected with the substrate (10), two vibrating diaphragm assemblies and two back pole plates which are positioned between the first supporting piece (20) and the second supporting piece (30) and are distributed in a staggered mode, wherein a cavity is formed in the substrate (10), the first supporting piece (20) partially seals one side of the cavity, and the second supporting piece (30) is positioned in the cavity; each diaphragm assembly comprises a first diaphragm (511) and a second diaphragm (512) fixedly connected with the first diaphragm (511) and arranged at intervals, and the second diaphragm (512) is positioned between the first diaphragm (511) and the corresponding back plate;

in the thickness direction of the substrate (10), one ends of two first diaphragms (511) and two back plates in the two diaphragm assemblies are respectively and fixedly connected with the first supporting part (20), the other ends of the two first diaphragms (511) and the two back plates in the two diaphragm assemblies are respectively and fixedly connected with the second supporting part (30), the edges of two second diaphragms (512) in the two diaphragm assemblies are suspended, and the two first diaphragms (511), the two back plates, the first supporting part (20) and the second supporting part (30) jointly divide the cavity into at least one back cavity (60) and two first vibration cavities (810) and two second vibration cavities (820) which are isolated from each other;

wherein one of the two diaphragm assemblies constitutes a first electrode (510), the other of the two diaphragm assemblies constitutes a second electrode (520), one of the two backplate plates constitutes a third electrode (410), the other of the two backplate plates constitutes a fourth electrode (420), the first electrode (510) is located between the third electrode (410) and the fourth electrode (420), and the fourth electrode (420) is located between the first electrode (510) and the second electrode (520);

26. The microphone assembly of claim 25,

27. The microphone assembly of claim 26,

the first diaphragm (511), the second diaphragm (512) and the connecting portion (513) are all made of a conductive medium.

28. The microphone assembly of claim 27,

29. The microphone assembly of claim 27,

30. The microphone assembly of claim 27,

31. An electronic device comprising a microphone assembly as claimed in any one of claims 1 to 30.