CN221103561U

CN221103561U - Electrostatic loudspeaker

Info

Publication number: CN221103561U
Application number: CN202420707036.2U
Authority: CN
Inventors: 侯杰
Original assignee: Gettop Acoustic Co Ltd
Current assignee: Gettop Acoustic Co Ltd
Priority date: 2024-04-08
Filing date: 2024-04-08
Publication date: 2024-06-07
Anticipated expiration: 2034-04-08

Abstract

The present application provides an electrostatic speaker comprising: the vibrating diaphragm comprises an elastic film and a conductive layer arranged on the surface of the elastic film; the two fixing frames are respectively arranged at two sides of the vibrating diaphragm, and through holes are formed in the fixing frames; the two back electrode plates are respectively arranged at the outer sides of the two fixing frames, and each back electrode plate comprises a conductive electrode plate and an electret material layer arranged on the surface of the conductive electrode plate; the conducting layer is used for inputting alternating current audio voltage; the two electret material layers respectively store different charges so as to provide electric field force for driving the vibrating diaphragm. The electrostatic loudspeaker provided by the application has the advantages of simple structure, high sensitivity and small distortion.

Description

Electrostatic loudspeaker

Technical Field

The application relates to the technical field of speakers, in particular to an electrostatic speaker.

Background

The electrostatic speaker (electrostatic loudspeaker) refers to a speaker in which an extremely thin diaphragm moves back and forth under the action of electrostatic force, and is different from an electrodynamic speaker which relies on electromagnetic force to move the diaphragm back and forth. The vibrating diaphragm of the electrostatic loudspeaker has extremely light weight, so that the resolution is extremely good, and the verve of music is fully represented.

Typical electrostatic speaker structure: because the two fixed electrodes and the vibrating diaphragm form a (double) capacitance structure respectively, the electrostatic loudspeaker is also called a capacitance type loudspeaker.

Compared with the electric loudspeaker widely used at present, the electrostatic loudspeaker has a much simpler structure, does not have a magnet, but utilizes the synergistic effect of an audio signal source and a direct current polarized power supply to promote the surface of a vibrating diaphragm (a movable electrode) to accumulate charges with a certain density, so that the vibrating diaphragm is subjected to the action of an electric field with alternating directions and vibrates and sounds along with the audio signal source.

Because the electric field force acting on the diaphragm is proportional to the magnitude of the dc bias voltage, a high dc voltage, for example, about 500V is required, which obviously increases the complexity and difficulty of the speaker system, and affects the production cost and application popularity of the product.

In order to solve the above problems, an electret-structured electrostatic speaker has been developed that can reduce the complexity and production cost of the conventional electrostatic speaker, but the electret-structured electrostatic speaker in the prior art still has the problems of low sensitivity and high distortion.

Disclosure of Invention

In view of the above, the present application provides an electrostatic speaker to improve at least one of the problems of low sensitivity and high distortion in the prior art.

In order to achieve the above object, the technical solution of the embodiment of the present application is as follows:

an embodiment of the present application provides an electrostatic speaker, including:

The vibrating diaphragm comprises an elastic film and a conductive layer arranged on the surface of the elastic film;

the two fixing frames are respectively arranged at two sides of the vibrating diaphragm, and through holes are formed in the fixing frames;

The two back electrode plates are respectively arranged at the outer sides of the two fixing frames, and each back electrode plate comprises a conductive electrode plate and an electret material layer arranged on the surface of the conductive electrode plate;

The conducting layer is used for inputting alternating current audio voltage; the two electret material layers respectively store different charges so as to provide electric field force for driving the vibrating diaphragm.

In one embodiment, the thickness of the elastic film is not greater than 10 μm, and/or the distance between the diaphragm and each of the back electrode plates is respectively in the range of 0.05mm to 3mm.

In one embodiment, the surface of the conductive layer is provided with a plurality of peak portions, and the height of the peak portions is not greater than 0.5mm.

In one embodiment, the diaphragm includes one elastic film and two conductive layers, the two conductive layers are respectively disposed on opposite surfaces of the elastic film, and the two conductive layers are respectively used for inputting the same ac audio voltage.

In one embodiment, a positioning groove recessed inwards is respectively formed in one side, close to the corresponding back electrode plate, of each fixing frame, and the back electrode plates are installed in the positioning grooves.

In one embodiment, the fixing frame includes an insulating portion, and at least one of the fixing frames further includes a conducting portion, the conducting portion and the conducting layer are arranged in a conducting manner, the conducting portion is arranged on one side, close to the vibrating diaphragm, of the fixing frame, an input pin is arranged on the edge of the conducting portion in a protruding manner, and the input pin is used for being connected with the alternating current audio voltage.

In one embodiment, the back plate has a thickness in the range of 0.05mm to 3mm and the electret material layer has a thickness in the range of 1 μm to 100 μm.

In one embodiment, two back electrode plates are symmetrically arranged on two sides of the vibrating diaphragm, and each electret material layer is arranged towards one side close to the vibrating diaphragm.

In one embodiment, the electret material layer is made of polytetrafluoroethylene or perfluoroethylene propylene copolymer; the conductive polar plate is made of stainless steel or nickel-plated copper.

In one embodiment, the electrostatic speaker further includes a supporting pad, the supporting pad is disposed between each of the back electrode plates and the diaphragm, and the plurality of supporting pads are distributed along the surface of the diaphragm in a dispersed manner.

The application has at least the following beneficial effects: according to the electrostatic loudspeaker provided by the embodiment of the application, the fixed frame and the back electrode plate are respectively arranged on the two sides of the vibrating diaphragm in sequence, the distance between the vibrating diaphragm and the back electrode plate is determined by the local thickness of the fixed frame, and the distance between the vibrating diaphragm and the back electrode plate can meet the design requirement by controlling the thickness of the fixed frame, so that the assembly process is simpler. Meanwhile, different charges are respectively stored in electret material layers of the back electrode plates, so that direct-current bias voltage is generated between the two back electrode plates, an external power amplifier or circuit is not needed any more to provide bias voltage for an electrostatic field, and the complexity of a loudspeaker structure is reduced. The two electret material layers are respectively stored with positive charges and negative charges, so that the voltage generated by static charges in the electret material layers can be doubled, meanwhile, the static charges are more stable to store due to attraction of the positive charges and the negative charges, the driving force of the vibrating diaphragm is more symmetrical, the output sensitivity and the frequency curve of the loudspeaker are improved, the distortion is reduced, and the stability of a product is improved.

Drawings

Fig. 1 is a schematic diagram of the overall structure of an electrostatic speaker according to an embodiment of the present application.

Fig. 2 is an exploded view of the electrostatic speaker of fig. 1.

Fig. 3 is a schematic cross-sectional structure of the electrostatic speaker of fig. 1.

Fig. 4 is a schematic diagram of a partially exploded structure of an electrostatic speaker according to an embodiment of the present application.

Fig. 5 is a schematic diagram of a part of an assembled structure of an electrostatic speaker according to an embodiment of the present application.

Fig. 6 is a schematic diagram of a stress state of the diaphragm at a certain moment (in the figure, + represents the polarity of an electric field of the diaphragm, ⊖ represents negative charges stored in the electret material layer, ⇩ represents positive charges stored in the electret material layer, and the stress direction of the diaphragm).

Fig. 7 is a schematic diagram of a stress state of the diaphragm at another instant (in the figure, the polarity of the electric field of the diaphragm is represented, ⊖ represents negative charges stored in the electret material layer, positive charges stored in the electret material layer are represented, and ⇧ represents the stress direction of the diaphragm).

The meaning of the various reference numerals in the drawings is as follows:

1. A protective assembly; 11. a cushion pad; 12. a protective layer; 13. a cover body;

2. A fixed frame; 21. an input pin; 22. an insulating part; 23. a conduction part; 24. a positioning groove; 25. a through hole;

3. a vibrating diaphragm; 31. an elastic film; 32. a conductive layer;

4. A back plate; 41. a conductive plate; 42. a layer of electret material; 43. and a through hole.

Detailed Description

The technical scheme of the application is further elaborated below by referring to the drawings in the specification and the specific embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the implementations of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

In the description of the present application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.

Referring to fig. 1 to 3, an electrostatic speaker according to an embodiment of the application includes: a vibrating diaphragm 3, two fixing frames 2 and two back electrode plates 4.

As shown in fig. 4 and 5, in some embodiments, the diaphragm 3 includes an elastic film 31 and a conductive layer 32 provided on a surface of the elastic film 31. The elastic membrane 31 of the diaphragm 3 may be a thin and elastic membrane, the smaller the thickness of which, the better the performance of the loudspeaker. For example, PPS (polyphenylene sulfide) film, PET (polyethylene terephthalate) film, or the like may be used, and the thickness of the elastic film 31 may be not more than 10 μm, for example, 2 μm, 3 μm, or the like. Specifically, the diaphragm 3 may be prepared by spreading the elastic film 31, fixing the elastic film 31 by a fixing device such as a clamp, placing the elastic film 31 with a certain tension in a vacuum furnace, and vacuum plating, to form a conductive layer 32 on the surface of the elastic film 31, wherein the conductive layer 32 may be made of nickel, for example. Alternatively, the conductive layer 32 may be formed by surface coating, or the material of the conductive layer 32 may be carbon powder or graphene. When the diaphragm 3 with the structure is connected with alternating audio voltage, one alternating audio voltage can be connected with the conductive layer 32 of the diaphragm 3, and the other audio voltage can be grounded.

Alternatively, in other embodiments, the diaphragm 3 may also include an elastic film 31 and two conductive layers 32, where the two conductive layers 32 are disposed on opposite surfaces of the elastic film 31. When the vibrating diaphragm 3 with the structure is connected with alternating audio voltage, one alternating audio voltage can be connected with the conductive layers 32 on two sides of the vibrating diaphragm 3 respectively, and the other alternating audio voltage is grounded.

The vibrating diaphragm 3 of the embodiment of the application has the advantages of very thin thickness, very small vibration quality, good transient response of output sound pressure of products, and high frequency response range of high frequency band, and can reach more than 36KHz after detection.

To further increase the driving force of the electric field on the diaphragm 3, spikes (not shown) may also be provided on the conductive layer 32. The height of the spikes is preferably no more than 0.5mm. Specifically, for example, a substrate for preparing the elastic film 31 may be placed on a mold having micropores, and then subjected to a high temperature and a high pressure to obtain the elastic film 31 having many irregular fine peak protrusions on the surface, and then the elastic film 31 is vacuum-plated, so that the obtained conductive layer 32 may have many irregular fine peak protrusions, thereby forming peak portions. The fine protrusions of the peak portions enhance the average electrostatic field intensity applied to the diaphragm 3, thereby improving the driving electric field force to the diaphragm 3 and further improving the output sound pressure of the electrostatic speaker. Alternatively, the peak portion may be obtained by roughening the conductive layer 32, and the specific method of manufacturing the peak portion is not limited.

The two fixed frames 2 are respectively arranged at two sides of the vibrating diaphragm 3, through holes 25 are formed in the fixed frames 2, the vibrating diaphragm 3 can vibrate in space at the through holes 25, and the distance between the vibrating diaphragm 3 and the back electrode plate 4 can be limited by the local thickness of the fixed frames 2, so that the vibrating diaphragm meets the design requirements, and the vibrating diaphragm is not too large nor too small.

Specifically, the fixed frame 2 includes an insulating portion 22, and at least one fixed frame 2 further includes a conducting portion 23, where the conducting portion 23 and the conductive layer 32 are in conducting arrangement, preferably the conducting portion 23 is disposed on a side of the fixed frame 2 near the diaphragm 3, and an input pin 21 is protruding from an edge of the conducting portion 23, where the input pin 21 is used for accessing the ac audio voltage. When the conductive layer 32 is disposed on only one side surface of the diaphragm 3, only one of the fixing frames 2 is required to be correspondingly provided with the conductive portion 23, and of course, both fixing frames 2 may be provided with the conductive portion 23. When the conductive layers 32 are respectively disposed on the two side surfaces of the diaphragm 3, the two fixing frames 2 are required to be provided with the conducting portions 23, and each conducting portion 23 is provided with one input pin 21 respectively to be connected with the two conductive layers 32 respectively. One side (i.e. the side close to the back plate 4) of each fixed frame 2, which is opposite to the vibrating diaphragm 3, is respectively provided with an inwards concave positioning groove 24, each positioning groove 24 is correspondingly provided with one back plate 4, and the positioning grooves 24 are arranged to facilitate the accurate positioning of the back plates 4 and simplify the assembly process. The insulating parts 22 of the two fixing frames 2 can be made of epoxy glass cloth plates (namely, the base material of a PCB), the conducting parts 23 can be made of copper-clad plates, and the two fixing frames 2 and the vibrating diaphragm 3 clamped by the two fixing frames can be fixed through connecting pieces such as bolts. The material of the fixing frame 2 is not particularly limited as long as the insulating function of the insulating portion 22 and the conductive function of the conductive portion 23 are satisfied, for example, the conductive portion 23 may be a metal or non-metal material satisfying the above requirements, such as plastic or ceramic after the surface is subjected to conductive treatment.

Two back electrode plates 4 are respectively arranged on the outer side (the side far away from the vibrating diaphragm 3) of the corresponding fixed frame 2, and each back electrode plate 4 comprises a conductive electrode plate 41 and an electret material layer 42 arranged on the surface of the conductive electrode plate 41. The electret material layers 42 of the two back-electrode plates 4 store different charges, respectively, to form an electric field force driving the diaphragm 3. A certain number of through holes 43 are uniformly formed in each back plate 4, and the through holes 43 can play a role in adjusting air compliance (air elasticity or hardness) and acoustic damping. The electret material layer 42 is usually made of PTFE (polytetrafluoroethylene) or an electret material such as FEP (fluorinated ethylene propylene copolymer or perfluoroethylene propylene copolymer). The conductive plate 41 is made of a conductive material, such as stainless steel sheet metal, nickel-plated copper sheet metal, or other surface-conductive material. The thickness of the back plate 4 ranges from 0.05mm to 3mm, wherein the thickness of the electret material layer 42 is 1 μm to 100 μm, the thickness of the back plate 4 is preferably 0.1mm to 0.3mm, and the thickness of the electret material layer 42 is preferably 20 μm to 50 μm. The back electrode plate 4 with the specification is easier to process, and the stored charge quantity is larger, so that the electrostatic field has larger driving force. Specifically, positive and negative high voltage polarizations may be used to cause electret material layers 42 to store dissimilar charges, for example, one electret material layer 42 uses negative high voltage polarization of-11 KV and the other electret material layer 42 uses positive high voltage polarization of +11 KV.

The distance between the vibrating diaphragm 3 and the two back polar plates 4, namely the vibrating space of the vibrating diaphragm 3, is determined by the local structure thickness of the fixed frame 2, so that the requirement on the assembly process is simplified in design, and meanwhile, the complete symmetry of the vibrating space of the vibrating diaphragm 3 is ensured.

The electrostatic speaker of the embodiment of the application preferably uses the PTFE film as the electret material layer 42, which can store charges more stably, and simultaneously selects the PPS or PET film which is light and thin and easy to drive as the main material of the vibrating diaphragm 3, and places the prepared vibrating diaphragm 3 in the middle of the two back polar plates 4 to form PUSH-PULL symmetrical driving, so that the design not only improves the output sound pressure of the product, but also reduces the distortion of the product, and simultaneously reduces the driving voltage and the complexity of the structural design of the product.

In assembling the diaphragm 3, the fixing frame 2, and the back plate 4, the following method (the diaphragm 3 having only one conductive layer 32 is taken as an example) may be adopted: the side of one fixed frame 2 (the side not provided with the conducting part 23) provided with the positioning groove 24 can be placed downwards, the side of the conducting layer 32 of the vibrating diaphragm 3 can be arranged upwards (or downwards, the steps can be correspondingly adjusted), one side of the elastic film 31 is fixed on the upper surface of the fixed frame 2, and the side of the other fixed frame 2 provided with the positioning groove 24 is placed upwards, so that the conducting part 23 is pressed on the conducting layer 32 and well contacted. The external ac audio voltage can be connected to the conductive layer 32 of the diaphragm 3 through the input pin 21. After the diaphragm 3 and the fixed frame 2 are assembled, the two back electrode plates 4 can be respectively installed in the positioning groove 24 of the fixed frame 2, and one side of the electret material layer 42 is placed towards one side of the groove bottom of the positioning groove 24.

Preferably, the two fixing frames 2 and the two back electrode plates 4 are respectively and symmetrically arranged relative to the center of the vibrating diaphragm 3, and the distance between the vibrating diaphragm 3 and each back electrode plate 4 is in the range of 0.05 mm-3 mm, preferably 0.1 mm-1 mm, which can ensure enough output sound pressure and is not easy to cause film absorption.

In a preferred embodiment, the two back electrode plates 4 are symmetrically arranged with the vibrating diaphragm 3 as a center, and the electret material layer 42 is arranged near one side of the vibrating diaphragm 3, and through holes 43 are respectively formed on the two back electrode plates 4 to allow air to pass freely, the fixing frame 2 is used for fixing the two back electrode plates 4 and the vibrating diaphragm 3, providing a vibrating gap space for the vibrating diaphragm 3, and meanwhile, the conducting part 23 of the fixing frame 2 provides an input connection of alternating current audio voltage for the conductive layer 32 (input pin 21) of the vibrating diaphragm 3.

According to the capacitor formula c=q/U (C is the capacitance value formed by the back-electrode plate 4 and the diaphragm 3, Q is the amount of charge stored after the back-electrode plate 4 resides, U is the voltage between the back-electrode plate 4 and the conductive layer 32 of the diaphragm 3), when the electret material layers 42 of the two back-electrode plates 4 are polarized to store charges, each electret material layer 42 storing charges corresponds to a dc voltage, and this voltage value u=q/C, so the structure does not need an external power amplifier or circuit to provide the bias voltage Vpol for the electrostatic speaker. Meanwhile, the polarization voltage of the two back electrode plates 4 is positive and negative, so that the direct current electric field generated by static charges is doubled, the electret material layers 42 are arranged inwards, the distance from the vibrating diaphragm 3 is kept to be minimized, the electric field force acting on the vibrating diaphragm 3 is higher (according to a formula, the higher the direct current voltage is, the smaller the distance from the vibrating diaphragm 3 is, the larger the electric field force acting on the vibrating diaphragm 3 is), and therefore the output sound pressure of the loudspeaker is also higher. The design of two backboard plates respectively storing positive and negative charges enables direct current voltage to be doubled, meanwhile, driving force of the vibrating diaphragm 3 is more symmetrical, output frequency curve of the electrostatic loudspeaker is optimized, and distortion is reduced.

In the preferred embodiment of this embodiment, the two back plates 4 and the diaphragm 3 are symmetrically arranged about the geometric center of the electrostatic speaker product, and when an ac audio voltage is applied to the diaphragm 3, the upper back plate 4 (in the drawing) is close to the diaphragm 3, and the lower back plate 4 is far from the diaphragm 3, and vice versa. The nonlinearity generated when the upper back plate 4 approaches the diaphragm 3 due to attractive force and the nonlinearity generated when the lower back plate 4 approaches the diaphragm 3 due to repulsive force are offset, and the mirror symmetry arrangement can greatly reduce the distortion of the output sound pressure of the product, so that the theoretical distortion of the product tends to zero, and the lossless high-quality audio signal output is provided.

The larger the distance between the diaphragm 3 and the back electrode plate 4 is, the higher the alternating current audio voltage required for obtaining the same sound pressure output is, which increases the complexity of a power amplifier or a circuit system; on the contrary, the smaller the distance between the diaphragm 3 and the back plate 4 is, the lower the alternating current audio voltage required for obtaining the same sound pressure output is, but the risk of film suction is increased, namely, the diaphragm 3 is adsorbed onto the back plate 4 by electrostatic force, so that the diaphragm 3 cannot vibrate freely, and the output sound pressure of a product is reduced sharply.

In order to further reduce the risk of film absorption, a plurality of support pads (not shown) may be further disposed, the plurality of support pads may be uniformly distributed between the back plate 4 and the diaphragm 3, and two ends of each support pad may be fixed to the surfaces of the back plate 4 and the diaphragm 3 respectively, or only one end of each support pad may be fixed to the surface of the back plate 4, and the height of each support pad is similar to, for example, equal to or slightly smaller than, the distance between the diaphragm 3 and the back plate 4. The supporting pad can be a soft rubber pad, a silica gel pad and the like, the shape of the supporting pad is not limited, the supporting pad mainly plays a supporting role, and sounding faults caused by the fact that the vibrating diaphragm 3 is adsorbed on the back electrode plate 4 are avoided.

Further, as shown in fig. 1 to 3, the electrostatic speaker of the present embodiment may further be provided with a protection assembly 1, where two protection assemblies 1 are respectively disposed on the outer sides (the side far from the fixed frame 2) of the two back electrode plates 4, and the protection assembly 1 includes a cushion pad 11, a protection layer 12, and a cover 13 sequentially disposed. The cushion 11 is arranged towards one side close to the back plate 4, the cushion 11 can be made of materials with a buffering function, such as rubber, and the cushion 11 can enable the combination of the protection component 1 and the back plate 4, the fixing frame 2 and the vibrating diaphragm 3 to be firmer, avoid loosening, and play a role in buffering. The cover 13 may be made of any material having a certain structural strength, such as a base material of a PCB or a plastic. The protective layer 12 mainly protects the internal components from foreign matters entering and affecting the hearing of the loudspeaker or damaging the diaphragm 3 to cause product damage, and the material of the protective layer 12 can be air-permeable or sound-permeable, such as a dust screen. The protection component 1 can be fixed with the back plate 4, the fixing frame 2 and the vibrating diaphragm 3 component through bolts and other connecting pieces so as to form a complete electrostatic loudspeaker product.

The working principle of the electrostatic speaker of the present embodiment is as follows:

As shown in fig. 5, the diaphragm 3 provided with the conductive layer 32 is arranged between the two back plates 4 at a distance, preferably equidistant, from the two back plates 4, the two back plates 4 being symmetrically arranged on both outer sides of the diaphragm 3. The electret material layers 42 of the back-plates 4 are polarized with positive and negative high voltages, respectively, so that positive or negative static charges +q or-Q are stored in the electret material layers 42 of the two back-plates 4, which static charges create an intensified electrostatic field between the two back-plates 4.

As shown in fig. 6, assuming that the charge stored in the electret material layer 42 of the upper back plate 4 is positive and the charge stored in the electret material layer 42 of the lower back plate 4 is negative in the drawing, when an external ac audio voltage is applied to the conductive layer 32 of the diaphragm 3 through the input pin 21, assuming that the ac audio voltage on the conductive layer 32 of the diaphragm 3 is positive at a certain moment, the diaphragm 3 having positive polarity positioned in the center of the electrostatic field receives the repulsive force of the upper back plate 4 and receives the attractive force of the lower back plate 4 at the moment, and thus the diaphragm 3 is displaced from top to bottom in a direction approaching the lower back plate 4 at this moment. As shown in fig. 7, if the ac audio voltage on the conductive layer 32 of the diaphragm 3 is negative at a certain moment, the diaphragm 3 with positive polarity located in the center of the electrostatic field is attracted by the upper back plate 4 and is also repelled by the lower back plate 4 at that moment, so that the diaphragm 3 is displaced from bottom to top and moves in a direction approaching the upper back plate 4 at that moment. Thus, the vibrating diaphragm 3 will generate reciprocating vibration under the action of alternating audio voltage, thereby pushing the air at two sides to make sound. The vibrating diaphragm 3 is pushed and pulled by the upper back electrode plate 4 and the lower back electrode plate 4 at the same time, so that the stress and the movement of the vibrating diaphragm 3 have a superposition effect, and the output sound pressure can be improved.

Compared with the traditional loudspeaker, the electrostatic loudspeaker provided by the embodiment of the application has the advantages that the overall thickness is smaller than 5mm, the electrostatic loudspeaker belongs to an ultrathin design, and the electrostatic loudspeaker can meet the application scene with the light weight requirement, such as a new energy automobile and the like. The electrostatic loudspeaker provided by the embodiment of the application has the advantages of simple structure, light and thin design, simple assembly process, no need of rare metal raw materials such as rare earth and the like, low cost, high stability and excellent performance. Compared with a common electrostatic loudspeaker driven by direct-current bias voltage, the electric field force for driving the vibrating diaphragm is provided by the electret material layer, so that the complexity of a system and the complexity of product design are reduced, the charge storage is more stable, the driving force of the vibrating diaphragm is more symmetrical, the output sensitivity and frequency curve of the loudspeaker are improved, the distortion is reduced, and the stability of the loudspeaker product is improved.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An electrostatic speaker, comprising:

2. An electrostatic loudspeaker according to claim 1, wherein the elastic membrane has a thickness of not more than 10 μm and/or the diaphragm and each of the back plates have a spacing in the range of 0.05mm to 3mm, respectively.

3. An electrostatic loudspeaker according to claim 1 or 2, wherein the surface of the conductive layer is provided with a plurality of peaks, the height of the peaks being no greater than 0.5mm.

4. An electrostatic loudspeaker according to claim 1, wherein the diaphragm comprises an elastic membrane and two conductive layers, the two conductive layers are respectively disposed on opposite surfaces of the elastic membrane, and the two conductive layers are respectively used for inputting the same ac audio voltage.

5. An electrostatic loudspeaker according to claim 1, wherein each of the fixing frames is provided with an inwardly recessed positioning groove on a side thereof adjacent to the corresponding back plate, and the back plate is mounted in the positioning groove.

6. An electrostatic loudspeaker according to claim 1, wherein the fixed frame comprises an insulating portion, at least one of the fixed frames further comprises a conducting portion, the conducting portion and the conducting layer are arranged in a conducting manner, the conducting portion is arranged on one side of the fixed frame, which is close to the diaphragm, an input pin is arranged on the edge of the conducting portion in a protruding manner, and the input pin is used for connecting the ac audio voltage.

7. The electrostatic speaker of claim 1, wherein the back plate has a thickness in the range of 0.05mm to 3mm and the electret material layer has a thickness in the range of 1 μm to 100 μm.

8. An electrostatic loudspeaker according to claim 1, wherein two of the back plates are symmetrically disposed on opposite sides of the diaphragm, each of the electret material layers being disposed toward a side adjacent to the diaphragm.

9. The electrostatic speaker of claim 1, wherein the electret material layer is polytetrafluoroethylene or perfluoroethylene propylene copolymer; the conductive polar plate is made of stainless steel or nickel-plated copper.

10. An electrostatic loudspeaker according to claim 1, further comprising a support pad, wherein the support pad is disposed between each of the back-electrode plates and the diaphragm, and a plurality of the support pads are distributed along the surface of the diaphragm.