A thin film electro-acoustic conversion device and an audio-visual system

Abstract

The application discloses a thin film electroacoustic conversion device and an audio-visual system. The thin film electroacoustic conversion device comprises an electrode assembly and a vibrating diaphragm. When the electrode assembly is applied with an alternating electric field, the alternating electric field can act on the vibrating diaphragm to make the vibrating diaphragm produce mechanical vibration. The vibrating diaphragm is composed of a plurality of micro-nano fibers. The micro-nano fibers form a plurality of vibration modes through the firm degree of adhesion and the distribution of the distance between the consolidation points. The application executes electroacoustic conversion through the cooperation of the electrode assembly and the vibrating diaphragm. The vibrating diaphragm is composed of micro-nano fibers. The micro-nano fibers form a microstructure with a plurality of mechanical vibration modes. The micro-nano fiber membrane can be deformed greatly under the excitation of an audio electric field and has a good response to electric signals in a wide audio frequency range, thereby exciting high-energy-density wide-frequency sound waves and significantly improving the frequency response performance of the electroacoustic conversion device. Therefore, on the basis of low power consumption of the thin film electroacoustic conversion device, higher sound quality is further considered.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of loudspeaker technology, and in particular to a thin film electro-acoustic conversion device and an audio-visual system. BACKGROUND

[0002] The description in this section merely provides background information related to the present disclosure and does not constitute the prior art.

[0003] The rapid development of the Internet of Things has dramatically increased the demand for light and thin flexible electronic products, including light and thin flexible electro-acoustic conversion devices, also known as loudspeakers.

[0004] Unlike traditional loudspeakers, thin film flexible loudspeakers are not only light in weight, but also can be bent and attached to the surface of various objects (such as robot skin, human skin, curtain, flexible display screen, etc.), which is a new type of electronic device.

[0005] Lightness, flexibility, low power consumption, and high electro-acoustic performance are the goals of the development of such loudspeakers. Traditional electrostatic loudspeakers use a bias power supply to provide an electrostatic field to the diaphragm, and drive the diaphragm to vibrate under the electrostatic force of the electrostatic field, thereby exciting sound waves. Such loudspeakers have high power consumption.

[0006] To improve the above problems, some prior art such as Chinese invention patent CN 103313174A provides a technical solution of an electret thin film loudspeaker, which uses the electrostatic field generated by the electret to drive the electret thin film to vibrate and excite sound waves. Compared with traditional electrostatic loudspeakers, the power consumption of the electret loudspeaker is lower.

[0007] However, the sound source of the above-mentioned traditional electrostatic loudspeaker and electret thin film loudspeaker is generated by the vibration of the thin film, and therefore the limitation of the vibration mode of the thin film determines the performance of the loudspeaker, resulting in unsatisfactory frequency response performance, and the dual requirements of high sound quality and low power consumption cannot be met.

[0008] It should be noted that the above introduction to the technical background is only to facilitate a clear and complete description of the technical solutions of the present application, and to facilitate the understanding of those skilled in the art. The above technical solutions cannot be considered as known to those skilled in the art merely because they are described in the background section of the present application. SUMMARY

[0009] The technical problem to be solved by the present application is to provide a thin film electro-acoustic conversion device and an audio-visual system, which can achieve high sound quality and low power consumption.

[0010] To solve the above technical problems, the present application provides a thin film electro-acoustic conversion device, comprising an electrode assembly and a diaphragm, when the electrode assembly is applied with an alternating electric field, the alternating electric field can act on the diaphragm to make the diaphragm produce mechanical vibration.

[0011] The diaphragm is composed of at least a plurality of micro-nano fibers, and a plurality of vibration modes are formed between the micro-nano fibers by the firmness of adhesion and the distribution of solidification point distance.

[0012] Further, part of the micro-nano fibers in the diaphragm are tightly bonded to form adhesion points, and the micro-nano fibers are divided into a plurality of fiber segments of different lengths by the adhesion points.

[0013] Further, the length distribution range of a plurality of the fiber segments is 0.05-500μm.

[0014] Further, the fiber diameter of the micro-nano fiber is 0.005-10μm, and the fiber stiffness is 0.5-50Mpa

[0015] Further, the diaphragm has a pore size of 50-500nm, a porosity of 20-95%, and a thickness of 3-6μm.

[0016] Further, the tensile modulus of the diaphragm in the extension direction is 10-600MPa, and the elastic modulus in the thickness direction is 0.14kPa-2MPa.

[0017] Further, the electrode assembly comprises a first electrode and a second electrode arranged oppositely in a plane, and the diaphragm comprises a first micro-nano fiber network and a second micro-nano fiber network arranged oppositely.

[0018] The first electrode, the first micro-nano fiber network, the second micro-nano fiber network and the second electrode are sequentially stacked.

[0019] And the first electrode, the first micro-nano fiber network, the second micro-nano fiber network and the second electrode are electrically isolated.

[0020] Further, a central conductive layer is further arranged between the first micro-nano fiber network and the second micro-nano fiber network.

[0021] And the central conductive layer is electrically isolated from the first micro-nano fiber network and the second micro-nano fiber network.

[0022] Further, the central conductive layer and the first micro-nano fiber network are electrically isolated by at least a first dielectric layer.

[0023] Further, the central conductive layer and the second micro-nano fiber network are electrically isolated by at least a second dielectric layer.

[0024] The first dielectric layer and / or the second dielectric layer are insulating dielectric.

[0025] Further, the first micro-nano fiber web and / or the second micro-nano fiber web are injected with electric charges.

[0026] Further, the first dielectric layer and / or the second dielectric layer are injected with electric charges.

[0027] Further, the first electrode and the first micro-nano fiber web and / or the second micro-nano fiber web and the second electrode are separated by an insulating support layer, and the insulating support layer has a plurality of hole structures.

[0028] In another aspect, the present application also provides an audio-visual system comprising the above-mentioned thin-film electro-acoustic conversion device and a display device; the normal direction of the thin-film electro-acoustic conversion device is arranged in cooperation with the display direction of the display device.

[0029] Through the above technical solutions, the present application has the following advantages:

[0030] The present application performs electro-acoustic conversion by cooperation of the electrode assembly and the diaphragm, the diaphragm is composed of micro-nano fibers, and the micro-nano fiber has a plurality of mechanical vibration modes, the micro-nano fiber structure can have large deformation and a plurality of vibration frequencies with significant differences under the excitation of electric field, thereby exciting wide-band sound waves, and further improving the frequency response performance of the electro-acoustic conversion device; thus, on the basis of low power consumption of the thin-film electro-acoustic conversion device, higher sound quality is further considered. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a structural schematic diagram of an electro-acoustic conversion device provided by a typical embodiment of the present application;

[0032] Figure 2 is a frequency response performance test diagram of the electro-acoustic conversion device provided by a typical embodiment of the present application.

[0033] Explanation of reference signs:

[0034] 1, first electrode; 2, first micro-nano fiber web; 3, first dielectric layer; 4, central conductive layer; 5, second dielectric layer; 6, second micro-nano fiber web; 7, second electrode. DETAILED DESCRIPTION

[0035] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0036] It should be noted that, in the description of the present application, the terms "first", "second", etc. are only used for the purpose of description and distinguishing similar objects, and there is no sequence or relative importance between them. In addition, in the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0037] Referring to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application. Figure 1 A thin film electro-acoustic conversion device according to a preferred embodiment of the present application comprises an electrode assembly and a diaphragm. When an alternating electric field is applied to the electrode assembly, the alternating electric field can act on the diaphragm to make the diaphragm produce mechanical vibration. The diaphragm is composed of a plurality of micro-nano fibers, and a plurality of vibration modes are formed between the micro-nano fibers.

[0038] The electrode assembly can be a planar electrode assembly as shown in the drawings, or a curved surface type. Generally, it is usually planar, but the curved surface type, although slightly higher in processing difficulty, can match some specific structure surfaces to achieve profiling design. Regardless of the shape of the electrode assembly, any implementation that utilizes the above technical concept provided by the present application to achieve wide frequency response should fall within the protection scope of the present application.

[0039] In some embodiments, part of the micro-nano fibers in the diaphragm are tightly bonded to form bonding points, and the micro-nano fibers are separated into fiber segments of different lengths by the bonding points. The micro-nano fiber filament between two bonding points can be regarded as a cantilever beam with both ends fixed, which produces a plurality of bending vibration modes under the action of electric field force. The bending vibration mode of the cantilever beam is mainly determined by the bonding strength of the bonding points, the mechanical strength, diameter, and length of the fiber material, and other parameters. By controlling these parameters, a plurality of vibration modes of the fiber mesh membrane layer are generated, thereby effectively expanding the frequency response range.

[0040] For example, in the case where the mechanical strength, diameter, and bonding point strength of the fiber are unchanged, the length of the fiber between the bonding points determines the fundamental frequency of the 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 length of the fiber segment is widely distributed within a certain range, a plurality of vibration modes will be generated within the corresponding frequency band, thereby achieving good response of the loudspeaker within this frequency band, and further achieving relatively optimal frequency response performance in a very wide frequency range.

[0041] As some typical application examples of the above technical solutions, the composition, structure and function of the thin film electro-acoustic conversion device can be as follows:

[0042] As shown in Figure 1 An electro-acoustic conversion device can be composed of two audio signal electrodes, two micro-nano fiber networks, two dielectric layers, and a central conductive layer 4.

[0043] The audio signal electrodes include a first electrode 1 and a second electrode 7 arranged at the outermost measurement, which are preferably conductive films or sheets with holes, including but not limited to metal mesh film, metal punched film, metal-plated plastic mesh film, metal-plated plastic open hole film, non-metal conductive film or sheet, etc. The first electrode 1 and the second electrode 7 can use conductive films or sheets of the same material and structure, or different materials and structures. In use, audio electrical signals are loaded between the first electrode 1 and the second electrode 7.

[0044] The micro-nano fiber network includes a first micro-nano fiber network 2 and a second micro-nano fiber network 6, which are respectively arranged between the central conductive layer 4 and the two electrodes, and can be a mesh film composed of fibers with a diameter of 10 nanometers to 100 microns. The bonding part between the fibers can be loose, and part of it can be firm. The base material of the micro-nano fiber can be conductive, semi-conductive or insulating material. The micro-nano fiber can have a quasi-permanent oriented dipole charge and / or space charge, or can not have a charge. The first micro-nano fiber network 2 and the second micro-nano fiber network 6 can use the same material and structure, or different materials and structures. There can be a gap between the first micro-nano fiber network 2 and the first electrode 1 and maintained insulation; there can be a gap between the second micro-nano fiber network 6 and the second electrode 7 and maintained insulation, and the pores can be filled with air or other specific gases such as pure nitrogen.

[0045] In some very preferred embodiments, the power consumption of the thin film electro-acoustic conversion device can be reduced and the audio output performance can be enhanced by injecting quasi-permanent charges on the surface of the micro-nano fiber.

[0046] The preparation of the micro-nano fiber network can be prepared by various existing preparation technologies including melt blowing, solution electrostatic spinning, melt electrostatic spinning, 3D printing, photoelectric direct writing, single / dual stretching, etc. according to the performance of the base material.

[0047] In some very preferred embodiments, the base material of the micro-nano fiber is preferably polytetrafluoroethylene (PTFE) resin, which is prepared by referring to the preparation method of polytetrafluoroethylene porous membrane and its product ZL.1997102948.2. The fiber diameter, pore distribution, fiber stiffness, membrane thickness, air permeability, etc. of the micro-nano fiber network film are adaptively regulated according to the target speaker performance.

[0048] The first and second dielectric layers are insulating dielectric layers for spacing the central conductive layer 4 and the two micro-nano fiber meshes, which can have quasi-permanent orientation dipole charges and / or space charges, or can not have charges. The first and second dielectric layers can have the same material and structure, or different materials and structures. The first micro-nano fiber mesh 2 and the first dielectric layer can have an air gap therebetween, or can be attached together; the second micro-nano fiber mesh 6 and the second dielectric layer can have an air gap therebetween, or can be attached together.

[0049] The dielectric layer has at least the following functions: (1) when the dielectric layer is not charged, it enhances the relative strength of the electric field in the area of the micro-nano fiber mesh, thereby improving the sound quality and reducing the power consumption; (2) the dielectric layer itself can be charged, which can further enhance the electric field strength in the area of the micro-nano fiber mesh film; (3) when the micro-nano fiber mesh film is charged, the dielectric layer can prevent the loss of charges.

[0050] Thus, in some very preferred embodiments, the power consumption can be further reduced by injecting quasi-permanent charges into the dielectric layer, and the frequency response performance of the device can be further improved.

[0051] The central conductive layer can be a thin film or plate made of non-metallic or metallic material, which has a conductive ability. In use, a direct current voltage can be applied to the central conductive layer to improve the audio response, or no direct current voltage can be applied.

[0052] When the audio signal is applied between the first electrode 1 and the second electrode 7 of the loudspeaker, the micro-nano fibers vibrate in multiple modes under the action of the electric field to generate sound waves in the medium. In combination with the above analysis, the generated sound waves have excellent and wide frequency response performance.

[0053] Thus, the embodiment of the present application provides an ultrathin, high-flexibility, and ultralow-power-consumption electro-acoustic conversion device. The electro-acoustic conversion device preferably uses a micro-nano fiber mesh as a vibration unit to excite sound waves, which is not only thin and bendable, but also has ultralow power consumption. The controllable multi-modal vibration of the fiber mesh film vibration unit can be realized by adjusting the base material performance, fiber diameter, mechanical strength, and structure parameters of the fiber mesh film, and the sound effect is pleasant. In addition, since the sound spreads from the large-area mesh film, the sound has strong penetration and has a sound directional function. If a high-definition flexible screen is combined into an audio-visual device, the audio-visual effect is excellent, and more possibilities are provided for high-quality life.

[0054] Based on the excellent performance of the thin film electro-acoustic conversion device provided by the present application, the embodiment of the present application further provides an audio-visual system, which comprises the above-mentioned thin film electro-acoustic conversion device and a display device; the normal direction of the thin film electro-acoustic conversion device is arranged in cooperation with the display direction of the display device.

[0055] In the display device, the display direction has a specific viewing position, the normal direction of the thin-film acoustic conversion device (usually refers to the sound axis direction of the thin-film acoustic conversion device, that is, the direction with the maximum sound pressure level) is also 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 structure such as the wall of a concert hall.

[0056] Of course, how to set the relative position of the sound and the display is not the key technical means of the present application, and those skilled in the art can adaptively design / adjust the above-mentioned cooperation based on the excellent performance of the thin-film acoustic conversion device provided by the present application.

[0057] In order to facilitate the understanding of the technical scheme of the present application, the embodiments of the present application are further illustrated in combination with specific implementation examples. However, it should be understood that the specific examples below are only used to illustrate the present application, and do not limit the protection scope of the present application.

[0058] Example 1

[0059] 1. Preparation of materials

[0060] Audio signal electrode: the first electrode 1 and the second electrode 7 adopt the same structure of components.

[0061] An audio signal electrode material is obtained by coating an aluminum layer with a thickness of 2 microns on the surface of a PET sheet with a circular hollow structure with a thickness of 0.5 millimeters and an A4 paper size. A total of 2 sheets are prepared, which are the first electrode 1 and the second electrode 7 respectively.

[0062] Micro-nano fiber membrane: the first micro-nano fiber membrane 2 and the second micro-nano fiber membrane 6 both adopt a PTFE micro-nano fiber membrane with an A4 paper size.

[0063] The specific preparation of the PTFE micro-nano fiber membrane refers to the implementation of the invention patent (Preparation method of polytetrafluoroethylene porous membrane and product ZL.1997102948.2). By adjusting the specific preparation parameters, the mechanical property anisotropy of the prepared PTFE micro-nano fiber membrane is that the mechanical properties in the machine stretching direction and perpendicular to the machine stretching direction are the same, and the tensile modulus is 600 MPa; and the elastic modulus in the thickness direction of the membrane is only 0.2 kPa. The diameter of the PTFE fiber is 1 micron, the thickness of the membrane is distributed between 3-6 microns, the porosity is about 90%, and the pore size is distributed in the range of 50 to 100 nanometers.

[0064] Dielectric layer: The first and second dielectric layers use the same polypropylene film. Specifically, a 50-micron-thick gas-solid binary polypropylene dielectric film with a relative permittivity of 1.8 is used, and its size is slightly larger than that of an A4 sheet of paper.

[0065] Conductive layer: Aluminum is used as the conductive layer.

[0066] 2) Specific manufacturing process of loudspeakers

[0067] First, a 2-micrometer-thick aluminum conductive layer is deposited on one side of both the first dielectric layer 3 and the second dielectric layer 6 using thermal evaporation deposition technology, serving as half of the central conductive layer 4. On the other side, a charge density of 0.5 mC / m is deposited using corona injection. 2 The negative charge, and according to Figure 1 The structure shown stacks the first dielectric layer 3 and the second dielectric layer 6 back-to-back to form a central conductive layer 4. Then, a first PTFE micro / nanofiber mesh 2 is attached to the charged surface of the first dielectric layer 3, and a second PTFE micro / nanofiber mesh 6 is attached to the charged surface of the second dielectric layer 6. A first electrode 1 is then placed on the surface of the first PTFE micro / nanofiber mesh 2, with a 10mm aperture, 2mm spacing, and 0.5mm thickness square-pore polyethylene terephthalate mesh serving as an insulating support layer between them. A second electrode 7 is placed on the surface of the second PTFE micro / nanofiber mesh 6, with a 10mm aperture, 2mm spacing, and 0.5mm thickness square-pore polyethylene terephthalate film serving as an insulating support layer between them. The stacking order of the components is as follows: Figure 1 As shown. Finally, the device is sealed around its perimeter with insulating tape.

[0068] 3) Speaker performance testing

[0069] A 2V audio signal was applied between the first electrode 1 and the second electrode 7. The frequency response curve of the speaker, obtained at a position 500mm from the central axis of the speaker, is shown below. Figure 2 As shown, the electroacoustic conversion device provided in this embodiment of the invention exhibits excellent frequency response performance within the frequency range audible to the human ear.

[0070] Example 2

[0071] This embodiment is largely the same as Embodiment 1, with the only difference being:

[0072] The first micro / nano fiber web 2 and the second micro / nano fiber web 6 were injected with the same density of charge as in Example 1.

[0073] The quasi-permanent charge injected on the surface of the micro-nano fiber can reduce the power consumption of the thin film electro-acoustic conversion device, while enhancing the audio output performance. Therefore, under the same commonly used playing intensity, the power consumption of the thin film electro-acoustic conversion device prepared in the embodiment is about 50% lower than that of embodiment 1.

[0074] Embodiment 3

[0075] The embodiment is basically the same as embodiment 1, and the difference is only that:

[0076] Neither the first dielectric layer nor the second dielectric layer is injected with charge.

[0077] The thin film electro-acoustic conversion device obtained in the embodiment is slightly higher in power consumption than that of embodiment 1, but is still at the same level as the electrostatic / thin film loudspeaker in the prior art, and at the same time, has the same frequency response performance curve as embodiment 1, and still has a significant improvement compared with the prior art.

[0078] Embodiment 4

[0079] The embodiment is basically the same as embodiment 1, and the difference is only that:

[0080] The first micro-nano fiber web 2 and the second micro-nano fiber web 6 are both replaced with polyvinylidene fluoride material, and the preparation method adopts a solution electrospinning process.

[0081] The tensile modulus of the micro-nano fiber web is 600 MPa, and the elastic modulus in the thickness direction of the web film is only 200 kPa. The diameter of the fiber is 0.1-0.3 microns, the thickness of the web film is distributed between 5-10 microns, the porosity is about 80%, and the pore size is distributed in the range of 100 to 500 nanometers.

[0082] The thin film electro-acoustic conversion device obtained in the embodiment has the same frequency response performance as embodiment 1, and still has a significant improvement compared with the prior art.

[0083] Embodiment 5

[0084] The embodiment is basically the same as embodiment 1, and the difference is only that:

[0085] The first micro-nano fiber web 2 and the second micro-nano fiber web 6 are both replaced with polypropylene material, and the preparation method adopts melt blowing.

[0086] The tensile modulus of the micro-nano fiber web is 1000 MPa, and the elastic modulus in the thickness direction of the web film is only 300 kPa. 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 size is distributed in the range of 50 to 300 nanometers.

[0087] The thin film electro-acoustic conversion device obtained in the embodiment has the same frequency response performance as that of the embodiment 1, and still has significant improvement compared with the prior art.

[0088] Comparative Example 1

[0089] The comparative example is basically the same as the embodiment 1, and the only difference is that:

[0090] The first micro-nano fiber web 2 and the second micro-nano fiber web 6 are both replaced by a common porous expanded PTFE film, and the thickness and size of the film are not changed, and the materials and sizes of the remaining structures of the device are also not changed.

[0091] Specifically, the common PTFE film used has a tensile modulus and a thickness direction elastic modulus of 600 MPa, a porosity of 0, and a thickness of 6 microns.

[0092] The thin film electro-acoustic conversion device prepared in the comparative example has a frequency response curve that is significantly inferior to that of the embodiment 1 in that it cannot have a high and uniformly distributed sound pressure level in such a wide range, especially in the frequency range of 1000-4000 Hz, the sound pressure level is significantly lower than that in the other frequency ranges, less than half of the high value.

[0093] Comparative Example 2

[0094] The comparative example is basically the same as the embodiment 1, and the only difference is that:

[0095] The PTFE micro-nano fiber web is prepared by the same method as the embodiment 1, but the tensile parameters are adjusted so that the tensile modulus of the prepared film is 50 MPa.

[0096] The thin film electro-acoustic conversion device prepared in the comparative example has a frequency response curve that is significantly inferior to that of the embodiment 1 in that it cannot have a high and uniformly distributed sound pressure level in such a wide range, especially in the frequency range of 2000-4000 Hz, the sound pressure level is significantly lower than that in the other frequency ranges, less than half of the high value.

[0097] This shows that in order to obtain excellent frequency response performance, it is necessary to control the microstructure of the PTFE micro-nano fiber web so that it has multiple vibration modes with large differences, and the key to obtaining the above-mentioned multi-modal microstructure is to adjust the parameters of the drawing process and the like by the method shown above to obtain a micro-nano fiber web with specific modulus, fiber diameter, thickness, porosity and pore size.

[0098] The above-described embodiments are merely preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Any equivalent substitutions or transformations made by those skilled in the art based on the present application are within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. A thin-film electroacoustic conversion device, comprising an electrode assembly and a vibrating diaphragm, wherein when an alternating electric field is applied to the electrode assembly, the alternating electric field can act on the vibrating diaphragm to cause the vibrating diaphragm to generate mechanical vibration; Its features are, The vibrating membrane is composed of at least a plurality of micro / nanofibers. The micro / nanofibers form multiple vibration modes through the strength of their adhesion and the distribution of the distance between their bonding points. The electrode assembly includes a first electrode and a second electrode arranged in a planar configuration opposite to each other. The vibrating membrane includes a first micro / nanofiber web and a second micro / nanofiber web arranged opposite to each other. The first electrode, the first micro / nanofiber web, the second micro / nanofiber web, and the second electrode are sequentially stacked. The first electrode, the first micro / nanofiber web, the second micro / nanofiber web, and the second electrode are all electrically isolated from each other. A central conductive layer is also provided between the first micro / nanofiber web and the second micro / nanofiber web. The central conductive layer is electrically isolated from the first micro / nanofiber web by at least a first dielectric layer, and the central conductive layer is electrically isolated from the second micro / nanofiber web by at least a second dielectric layer. The first dielectric layer and / or the second dielectric layer are both insulating dielectrics. Charge is injected into the first micro / nanofiber web and / or the second micro / nanofiber web. Charge is injected into the first dielectric layer and / or the second dielectric layer. An insulating support layer separates the first electrode and the first micro / nanofiber web and / or the second micro / nanofiber web and the second electrode. The insulating support layer has a plurality of pore structures.

2. The thin-film electroacoustic conversion device according to claim 1, characterized in that, The micro- and nano-fibers in the vibrating membrane are tightly bonded together to form adhesive points, and the micro- and nano-fibers are separated into fiber segments of various lengths by the adhesive points.

3. The thin-film electroacoustic conversion device according to claim 2, characterized in that, The length distribution of various fiber segments ranges from 0.05 to 500 μm.

4. The thin-film electroacoustic conversion device according to claim 1, characterized in that, The micro / nano fibers have a diameter of 0.005-10 μm and a stiffness of 0.5-50 MPa. And / or, the diaphragm has a pore size of 50-500 nm, a porosity of 20-95%, and a thickness of 0.5-30 μm; And / or, the tensile modulus of the vibrating diaphragm in the extension direction is 10-600 MPa, and the elastic modulus in the thickness direction is 0.14-2 kPa.

5. An audiovisual system, characterized in that, Includes the thin-film electroacoustic conversion device and the display device as described in any one of claims 1-4; The normal of the thin-film electroacoustic conversion device is set to match the display direction of the display device.

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