CN116112851A

CN116112851A - Film electroacoustic conversion device and audio-visual system

Info

Publication number: CN116112851A
Application number: CN202310176902.XA
Authority: CN
Inventors: 宫继业
Original assignee: Shanghai Dagong New Materials Co ltd
Current assignee: Shanghai Dagong New Materials Co ltd
Priority date: 2023-02-28
Filing date: 2023-02-28
Publication date: 2023-05-12

Abstract

The invention discloses a film electroacoustic conversion device and an audio-visual system. The film electroacoustic conversion device comprises an electrode assembly and a vibrating film, wherein when the electrode assembly is applied with an alternating electric field, the alternating electric field can act on the vibrating film to enable the vibrating film to generate mechanical vibration; the vibrating diaphragm is composed of a plurality of micro-nano fibers, and a plurality of vibration modes are formed among the micro-nano fibers through the firmness degree of adhesion and the distribution of the distances between the consolidation points. The electroacoustic conversion is carried out by matching the electrode assembly and the vibrating membrane, the adopted vibrating membrane is composed of micro-nano fibers, and the microstructure formed by the micro-nano fibers has various mechanical vibration modes, so that the micro-nano fiber membrane can be greatly deformed under the excitation of an audio electric field and has good response to an electric signal in a wide audio range, thereby exciting a high-energy-density broadband sound wave and further remarkably improving the frequency response performance of the electroacoustic conversion device; therefore, on the basis of low power consumption of the film electroacoustic conversion device, higher tone quality is further considered.

Description

Film electroacoustic conversion device and audio-visual system

Technical Field

The invention relates to the technical field of speakers, in particular to a film electroacoustic conversion device and an audio-visual system.

Background

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

The rapid development of intelligent networking has increased the demand for thin, lightweight, flexible electronic products, including thin, flexible electroacoustic transducers, also known as speakers.

Unlike traditional speaker, the film flexible speaker not only has light weight, but also can be bent, can be attached to object surfaces with various shapes (such as robot skin, human skin, curtain, flexible display screen, etc.), and is a novel electronic device.

Light and thin, flexibility, low power consumption, high electroacoustic performance, etc. are targets for the development of such loudspeakers. The traditional electrostatic loudspeaker utilizes a bias power supply to provide an electrostatic field for a vibrating membrane, and drives the vibrating membrane to vibrate under the electrostatic field force, so that sound waves are excited, and the power consumption of the loudspeaker is high.

In order to solve the above problems, some prior arts, such as chinese patent No. CN 103313174a, provide a technical solution of an electret film speaker, which uses an electrostatic field generated by an electret to drive the electret film to vibrate and excite sound waves. Electret speakers have lower power consumption than traditional electrostatic speakers.

However, the sound sources of the conventional electrostatic speaker and electret film speaker are generated by the vibration of the film, so that the limitation of the film vibration mode determines the performance of the speaker, which results in unsatisfactory frequency response performance and cannot satisfy the dual requirements of high sound quality and low power consumption.

It should be noted that the foregoing description of the background art is only for the purpose of providing a clear and complete description of the technical solution of the present invention and is presented for the convenience of understanding by those skilled in the art. The above-described solutions are not considered to be known to the person skilled in the art simply because they are set forth in the background of the invention section.

Disclosure of Invention

The invention aims to solve the technical problem of providing a film electroacoustic conversion device and an audio-visual system, which realize the combination of high tone quality and low power consumption.

In order to solve the technical problems described above, the present invention provides a thin film electroacoustic conversion device including an electrode assembly and a diaphragm, the alternating electric field being capable of acting on the diaphragm to cause the diaphragm to mechanically vibrate when the electrode assembly is applied with the alternating electric field;

the vibrating diaphragm is at least composed of a plurality of micro-nano fibers, and a plurality of vibration modes are formed among the micro-nano fibers through the distribution of the firmness degree of bonding and the distance between the consolidation points.

Further, part of micro-nano fibers in the vibrating membrane are tightly adhered to form bonding points, and the micro-nano fibers are separated into fiber fragments with different lengths by the bonding points.

Further, the length distribution of the plurality of fiber fragments ranges from 0.05 to 500 μm.

Further, the micro-nano fiber has a fiber diameter of 0.005 to 10 μm and a fiber stiffness of 0.5 to 50Mpa

Further, the aperture of the vibrating membrane is 50-500nm, the porosity is 20-95%, and the thickness is 3-6 mu m;

further, the tensile modulus of the diaphragm in the extension direction is 10 to 600MPa, and the elastic modulus in the thickness direction is 0.14kPa to 2 MPa.

Further, the electrode assembly comprises a planar first electrode and a planar second electrode which are oppositely arranged, and the vibrating membrane comprises a first micro-nano fiber net and a second micro-nano fiber net which are oppositely arranged;

the first electrode, the first micro-nano fiber net, the second micro-nano fiber net and the second electrode are sequentially stacked;

and the first electrode, the first micro-nano fiber net, the second micro-nano fiber net and the second electrode are all electrically isolated.

Further, a central conductive layer is arranged between the first micro-nano fiber net and the second micro-nano fiber net;

and the central conductive layer is electrically isolated from both the first micro-nano fiber web and the second micro-nano fiber web.

Further, the central conductive layer is electrically isolated from the first micro-nano fiber web by at least a first dielectric layer;

further, the central conductive layer is electrically isolated from the second micro-nano fiber web by at least a second dielectric layer;

the first dielectric layer and/or the second dielectric layer are/is insulating dielectric.

Further, the first micro-nano fiber net and/or the second micro-nano fiber net are/is injected with electric charges;

further, charges are injected into the first dielectric layer and/or the second dielectric layer.

Further, the first electrode and the first micro-nano fiber net and/or the second micro-nano fiber net and the second electrode are/is separated by an insulating supporting layer, and the insulating supporting layer is provided with a plurality of hole structures.

On the other hand, the invention also provides an audio-visual system which comprises the film electroacoustic conversion device and a display device; the normal direction of the film electroacoustic conversion device is matched with the display direction of the display device.

By the technical scheme, the invention has the following beneficial effects:

the electroacoustic conversion is carried out by matching the electrode assembly and the vibrating membrane, the adopted vibrating membrane is composed of micro-nano fibers, and the microstructure formed by the micro-nano fibers has various mechanical vibration modes, so that the micro-nano fiber structure can be greatly deformed under the excitation of an electric field and has various vibration frequencies with obvious differences, thereby exciting broadband sound waves and further obviously improving the frequency response performance of the electroacoustic conversion device; therefore, on the basis of low power consumption of the film electroacoustic conversion device, higher tone quality is further considered.

Drawings

Fig. 1 is a schematic structural diagram of an electroacoustic conversion device according to an exemplary embodiment of the present invention;

fig. 2 is a diagram for testing the frequency response performance of an electroacoustic transducer according to an exemplary embodiment of the present invention.

Reference numerals illustrate:

1. a first electrode; 2. a first micro-nano fiber web; 3. a first dielectric layer; 4. a central conductive layer; 5. a second dielectric layer; 6. a second micro-nano fiber web; 7. and a second electrode.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that, in the description of the present invention, the terms "first," "second," and the like are used for descriptive purposes only and to distinguish between similar objects, and there is no order of preference between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

Referring to fig. 1, a thin film electroacoustic transducer according to a preferred embodiment of the present invention includes an electrode assembly and a diaphragm, wherein when an alternating electric field is applied to the electrode assembly, the alternating electric field can act on the diaphragm to cause mechanical vibration of the diaphragm; the vibrating diaphragm is at least composed of a plurality of micro-nano fibers, and a plurality of vibration modes are formed among the micro-nano fibers.

The electrode assembly may be a planar electrode assembly as shown in the drawings, or may be a curved electrode assembly, and is generally configured as a planar electrode assembly, but the curved electrode assembly may be matched with some specific structural surfaces to realize a profile modeling design although the processing difficulty is slightly high, and any implementation mode that utilizes the technical concept provided by the present invention to realize broadband responsiveness should fall within the protection scope of the present invention.

In some embodiments, the bonding points are formed by closely adhering portions of the micro-nanofibers in the diaphragm, and the micro-nanofibers are separated into fiber segments of various lengths by the bonding points. The micro-nano fiber wires between two bonding points can be regarded as cantilever beams with two ends fixedly connected, and the cantilever beams generate various bending vibration modes under the action of electric field force. The bending vibration mode of the cantilever beam is mainly determined by parameters such as the bonding strength of bonding points, the mechanical strength of fiber materials, the diameter, the length and the like. And various vibration modes of the fiber mesh membrane layer are generated by controlling the parameters, so that the frequency response range is effectively widened.

For example, where the mechanical strength, diameter, and bond point strength of the fiber are unchanged, the length of the fiber between the bond points determines the fundamental frequency of the length of fiber. The shorter the fiber segment, the higher the fundamental frequency and the longer the fiber segment, the lower the fundamental frequency. Therefore, if the lengths of the fiber segments are widely distributed within a certain range, a plurality of vibration modes are generated in the corresponding frequency band, so that good response of the loudspeaker in the frequency band is realized, and better frequency response performance can be realized in a very wide frequency range.

As some typical application examples of the above technical solution, the composition, structure and function of the film electroacoustic conversion device may be as follows:

as shown in fig. 1, an electroacoustic conversion device may be composed of two audio signal electrodes, two micro-nano fiber webs, two dielectric layers, and one central conductive layer 4.

The audio signal electrode comprises a first electrode 1 and a second electrode 7 which are arranged at the outermost measurement, and is preferably a conductive film or a thin plate with holes, including but not limited to materials such as a metal net film, a metal punching film, a metal plating plastic net film, a metal plating plastic open pore film, a nonmetal conductive film or a thin plate. The first electrode 1 and the second electrode 7 may be made of conductive films or thin plates of the same material and structure, or may be made of conductive films or thin plates of different materials and structures. In use, an audio electrical signal is loaded between the first electrode 1 and the second electrode 7.

The micro-nano fiber net comprises a first micro-nano fiber net 2 and a second micro-nano fiber net 6 which are respectively arranged between the central conductive layer 4 and the two electrodes, and can be a net film formed by fibers with the diameter between 10 nanometers and 100 micrometers; the bonding between the fibers may be loose or the bonding may be strong; the substrate of the micro-nanofibers may be a conductive, semi-conductive or insulating material; the micro-nanofibers may or may not have a quasi-permanent oriented dipole charge and/or space charge. The first micro-nano fiber net 2 and the second micro-nano fiber net 6 can be made of the same material and structure, and can also be made of different materials and structures. A gap can be left between the first micro-nano fiber net 2 and the first electrode 1 and insulation can be maintained; the second micro-nano fiber net 6 and the second electrode 7 can be kept insulated by leaving a gap, and the gap can be filled with air or other specific gases such as pure nitrogen.

In some highly preferred embodiments, the power consumption of the thin film electroacoustic transducer device may be reduced while enhancing the audio output performance by injecting a quasi-permanent charge on the micro-nanofiber surface.

The micro-nano fiber net can be prepared by adopting various existing preparation technologies including melt blowing, solution electrostatic spinning, melt electrostatic spinning, 3D printing, photoelectric direct writing, single/two-way stretching and other production technologies according to the performance of the base material.

In some very preferred embodiments, the substrate of the micro-nano fiber is preferably Polytetrafluoroethylene (PTFE) resin, and the production process thereof is prepared by referring to the preparation method of the polytetrafluoroethylene porous membrane of the invention patent and the product ZL.1997102948.2. Parameters such as fiber diameter, pore distribution, fiber rigidity, web thickness, ventilation and the like of the micro-nano fiber web are adaptively regulated according to the performance of the target loudspeaker.

The first and second dielectric layers are insulating mediums for spacing the central conductive layer 4 and the two micro-nano fiber webs, which may or may not have a quasi-permanent oriented dipole charge and/or space charge. The first dielectric layer and the second dielectric layer can be made of the same material and structure, and can also be made of different materials and structures. An air gap can be reserved between the first micro-nano fiber net 2 and the first dielectric layer, and the first micro-nano fiber net and the first dielectric layer can be stuck together; an air gap can be left between the second micro-nano fiber net 6 and the second dielectric layer, and the second micro-nano fiber net and the second dielectric layer can be stuck together.

Wherein the dielectric layer functions at least include: (1) When the dielectric layer is not electrified, the dielectric layer has the function of enhancing the relative strength of the electric field of the area where the micro-nano fiber net is positioned, thereby improving the tone quality and reducing the power consumption; (2) The dielectric layer can be charged, so that the electric field strength of the micro-nano fiber net film area can be further enhanced; (3) When the micro-nano fiber net film is charged, the dielectric layer can avoid charge loss.

Thus in some highly preferred embodiments, the power consumption can be further reduced by injecting a quasi-permanent charge in the dielectric layer, further improving the frequency response performance of the device.

The central conductive layer can be a film or a plate made of nonmetal or metal and has conductivity. In use, a DC voltage may or may not be applied to the center conductive layer to enhance audio responsiveness.

When an audio signal is applied between the first electrode 1 and the second electrode 7 of the loudspeaker, the micro-nanofibers vibrate in multiple modes under the influence of an electric field to generate sound waves in the medium. In combination with the above analysis, the generated sound waves have excellent broad frequency response performance.

Therefore, the embodiment of the invention provides an ultra-thin, high-flexibility and ultra-low-power consumption electroacoustic conversion device. The electroacoustic conversion device preferably adopts the micro-nano fiber net as a vibration unit to excite sound waves, is light and thin and flexible, and has ultra-low power consumption. The controllable multi-mode vibration of the fiber web vibration unit can be realized through the regulation and control of the base material performance, the fiber diameter, the mechanical strength and the fiber web structural parameters of the micro-nano fiber, and the sound effect is pleasant. In addition, since sound propagates from the large area of the omentum, sound penetrating power is strong and sound directing function is provided. If the audio-visual equipment combined by the flexible screen with high definition has excellent audio-visual effect, more possibilities are provided for high-quality life.

Based on the excellent performance of the film electroacoustic conversion device, the embodiment of the invention also provides an audio-visual system which comprises the film electroacoustic conversion device and a display device; the normal direction of the film electroacoustic conversion device is matched with the display direction of the display device.

Wherein the mating arrangement is for example: the display device has a specific viewing position in a display direction, and a normal direction of the film electroacoustic conversion device (generally, a sound axis direction of the film electroacoustic conversion device, that is, a direction with a maximum sound pressure level) is opposite to the viewing position, or forms a specific angle with the viewing position, or is reflected to the viewing position based on some sound reflection structures, such as a wall of a concert hall.

Of course, how to set the relative positions of sound and display is not an important technical means of the present invention, and those skilled in the art can fully design/adjust the above-mentioned matching adaptively based on the excellent performance of the film electroacoustic conversion device provided by the present invention.

In order to facilitate understanding of the technical solution of the present invention, the following description will further illustrate embodiments of the present invention in conjunction with specific embodiments, however, it should be understood that the following specific embodiments are only for illustrating the present invention and do not limit the scope of protection of the present invention.

Example 1

1) Preparation of the Material

Audio signal electrode: the first electrode 1 and the second electrode 7 are members of the same structure.

And coating an aluminum layer with the thickness of 2 microns on the surface of the PET sheet with the circular hollowed-out structure and the thickness of 0.5mm and the size of A4 paper to obtain the audio signal electrode material. A total of 2 sheets were prepared, first electrode 1 and second electrode 7, respectively.

Micro-nano fiber net film: the first micro-nano fiber net 2 and the second micro-nano fiber net 6 adopt PTFE micro-nano fiber net films, and the sizes of the PTFE micro-nano fiber net films are A4 paper sizes.

Specific preparation of the PTFE micro-nano fiber net film is implemented by referring to the patent of the invention (a preparation method of a polytetrafluoroethylene porous film and a product ZL.1997102948.2), and the mechanical property of the prepared PTFE micro-nano fiber net film is anisotropic by adjusting specific preparation parameters: the mechanical properties of the machine stretching direction and the mechanical properties perpendicular to the machine stretching direction are the same, and the stretching modulus is 600MPa; whereas the modulus of elasticity in the web thickness direction is only 0.2kPa. The PTFE fiber has a diameter of 1 micron, a web thickness distribution of between 3 and 6 microns, a porosity of about 90%, and a pore size distribution in the range of 50 to 100 nanometers.

Dielectric layer: the first dielectric layer and the second dielectric layer use the same polypropylene film. The specific adoption is a 50-micron thick polypropylene dielectric film with a gas-solid binary structure, the relative dielectric constant is 1.8, and the size of the dielectric film is slightly larger than the size of A4 paper.

Conductive layer: aluminum is used as the conductive layer.

2) Specific preparation process of loudspeaker

Firstly, a 2-micrometer thick aluminum conductive layer is evaporated on one side of a first dielectric layer 3 and a second dielectric layer 6 to be used as a half of a central conductive layer 4 by using a thermal evaporation coating technology, and the upper charge density is 0.5mC/m on the other side by using a corona injection method ² And the first dielectric layer 3 and the second dielectric layer 6 are stacked back-to-back to form the central conductive layer 4 in accordance with the structure shown in fig. 1. The PTFE first micro-nano fiber web 2 is then attached to the charged surface of the first dielectric layer 3 and the PTFE second micro-nano fiber web 6 is attached to the charged surface of the second dielectric layer 6. Further, a first electrode 1 is placed on the surface of the PTFE first micro-nano fiber net 2, and a square hole polyethylene terephthalate net with the aperture of 10mm, the hole spacing of 2mm and the thickness of 0.5mm is used as an insulating supporting layer between the first electrode and the first electrode; a second electrode 7 was placed on the surface of the second micro-nano fiber web 6 of PTFE, and a square hole polyethylene terephthalate film sheet having a hole diameter of 10mm, a hole pitch of 2mm, and a thickness of 0.5mm was used as an insulating support layer therebetween. The stacking sequence of the components is shown in figure 1. And finally, bonding the periphery of the device by using a dielectric tape.

3) Performance test of speakers

An audio signal of 2V was applied between the first electrode 1 and the second electrode 7, and the frequency response curve of the speaker obtained at a position 500mm from the center axis of the speaker was as shown in fig. 2. It shows that the electroacoustic conversion device provided by the embodiment of the invention has very excellent frequency response performance in a frequency range which can be heard by human ears.

Example 2

This embodiment is substantially the same as embodiment 1, except that:

the first micro-nano fiber web 2 and the second micro-nano fiber web 6 were both charged with the same density in the same manner as in example 1.

The quasi-permanent charges are injected on the surface of the micro-nano fiber, so that the power consumption of the film electroacoustic conversion device can be reduced, and the audio output performance is enhanced, therefore, under the same common playing strength, the power consumption of the film electroacoustic conversion device manufactured by the embodiment is reduced by about 50% compared with that of the embodiment 1.

Example 3

This embodiment is substantially the same as embodiment 1, except that:

neither the first dielectric layer nor the second dielectric layer injects charge.

The thin film electroacoustic transducer of the present embodiment has the same level as the electrostatic/thin film speaker of the prior art, although the power consumption is slightly higher than that of embodiment 1, and at the same time, has the same frequency response performance curve as that of embodiment 1, and still has a significant improvement over the prior art.

Example 4

This embodiment is substantially the same as embodiment 1, except that:

the first micro-nano fiber net 2 and the second micro-nano fiber net 6 are replaced by polyvinylidene fluoride materials, and the preparation method adopts a solution electrostatic spinning process.

The tensile modulus of the micro-nano fiber web is 600MPa; whereas the modulus of elasticity in the web thickness direction is only 200kPa. The diameter of the fiber is 0.1-0.3 micrometers, the thickness of the net film is distributed between 5-10 micrometers, the porosity is about 80%, and the pore diameter is distributed in the range of 100-500 nanometers.

The thin film electroacoustic conversion device obtained in this example has the same frequency response performance as in example 1, and still has a significant improvement over the prior art.

Example 5

This embodiment is substantially the same as embodiment 1, except that:

the first micro-nano fiber net 2 and the second micro-nano fiber net 6 are replaced by polypropylene, and melt-blowing is adopted in the preparation method.

The tensile modulus of the micro-nano fiber web is 1000MPa; whereas the modulus of elasticity in the web thickness direction is only 300kPa. The diameter of the fiber is 0.5-2 microns, the thickness of the web film is distributed between 10-30 microns, the porosity is about 85%, and the pore diameter is distributed in the range of 50-300 nanometers.

Comparative example 1

This comparative example is substantially the same as example 1, except that:

the first micro-nano fiber net 2 and the second micro-nano fiber net 6 are replaced by common porous expanded PTFE films, the thickness and the size of the films are unchanged, and the materials/sizes of the other structures of the device are also unchanged.

Specifically, the tensile modulus and the elastic modulus in the thickness direction of the common PTFE film are 600MPa, the porosity is 0, and the thickness is 6 micrometers.

The film electroacoustic conversion device prepared in this comparative example has a significantly lower frequency response curve than that of example 1, and can have a higher and uniformly distributed sound pressure level in such a wide range, particularly in the frequency range of 1000 to 4000Hz, and the boost level is significantly reduced by less than half of the high value compared with the rest of the frequency range.

Comparative example 2

This comparative example is substantially the same as example 1, except that:

a PTFE micro-nano fiber web prepared in the same manner as in example 1 was used, but the stretching parameters thereof were adjusted so that the tensile modulus of the film prepared therefrom was 50MPa.

The film electroacoustic conversion device prepared in this comparative example has a significantly lower frequency response curve than that of example 1, and can have a higher and uniformly distributed sound pressure level in such a wide range, particularly in the range of 2000 to 4000Hz, and the sound pressure level is significantly reduced by less than half of the high value compared with the rest of the frequency band.

This means that in order to obtain excellent frequency response performance, the microstructure of the PTFE micro-nano fiber web needs to be controlled to have a plurality of vibration modes with large variability, and the key point of obtaining the multi-mode microstructure is to obtain the micro-nano fiber web with parameters such as specific modulus, fiber diameter, thickness, porosity and pore diameter by adopting the method of the above example and adaptively adjusting parameters of the process such as drawing.

The above-described embodiments are merely preferred embodiments for fully explaining the present invention, and the scope of the present invention is not limited thereto. Equivalent substitutions and modifications will occur to those skilled in the art based on the present invention, and are intended to be within the scope of the present invention. The protection scope of the invention is subject to the claims.

Claims

1. A thin film electroacoustic transducer comprising an electrode assembly and a diaphragm, the alternating electric field being capable of acting on the diaphragm to cause mechanical vibration of the diaphragm when the electrode assembly is applied with an alternating electric field;

the vibration film is characterized by at least comprising a plurality of micro-nano fibers, wherein a plurality of vibration modes are formed among the micro-nano fibers through the distribution of the firmness degree of adhesion and the distance between the consolidation points.

2. The membrane electroacoustic conversion device according to claim 1, wherein a portion of the micro-nanofibers in the diaphragm are tightly bonded to form bonding points, and the micro-nanofibers are separated into a plurality of fiber segments of different lengths by the bonding points.

3. The membrane electroacoustic conversion device according to claim 2, wherein the length distribution of the plurality of fiber segments ranges from 0.05 to 500 μm.

4. The membrane electroacoustic conversion device according to claim 1, wherein the micro-nanofiber has a fiber diameter of 0.005 to 10 μm and a fiber stiffness of 0.5 to 50MPa;

and/or the aperture of the vibrating membrane is 50-500nm, the porosity is 20-95%, and the thickness is 0.5-30 μm;

and/or the tensile modulus of the vibrating membrane in the extending direction is 10-600MPa, and the elastic modulus in the thickness direction is 0.14-2kPa.

5. The membrane electroacoustic conversion device of claim 1, wherein the electrode assembly comprises oppositely disposed planar first and second electrodes, and the diaphragm comprises oppositely disposed first and second micro-nanofiber webs;

6. The membrane electroacoustic conversion device of claim 5, wherein a central conductive layer is further disposed between the first micro-nano fiber web and the second micro-nano fiber web;

7. The membrane electroacoustic conversion device of claim 6, wherein the central conductive layer is electrically isolated from the first micro-nano web by at least a first dielectric layer;

and/or, the central conductive layer is electrically isolated from the second micro-nano fiber web by at least a second dielectric layer;

8. The membrane electroacoustic conversion device of claim 7, wherein the first micro-nano fiber web and/or the second micro-nano fiber web is injected with an electric charge;

and/or charges are injected into the first dielectric layer and/or the second dielectric layer.

9. The membrane electroacoustic conversion device of claim 5, wherein the first electrode and the first micro-nanofiber web and/or the second micro-nanofiber web and the second electrode are separated by an insulating support layer, and the insulating support layer has a plurality of hole structures.

10. An audiovisual system comprising a thin film electroacoustic conversion device as claimed in any one of claims 1 to 9 and a display device;

the normal direction of the film electroacoustic conversion device is matched with the display direction of the display device.