TWI462598B - Method of manufacturing electret films and loudspeakers comprising the same - Google Patents

Description

Method for manufacturing electret film and speaker including the same

This invention relates to electret materials, and more particularly to an electret speaker and method of making same.

An electrostatic speaker is based on coulomb's law, and two conductors having different or identical charges can produce a push or pull force. Alternating push-pull electrostatic forces can cause vibrations with electrostatically charged diaphragms and thus produce sound. An electrostatic speaker typically includes two porous conductive plates or electrode plates and a vibrating plate interposed between and driven by the conductive plates or electrode plates. An air gap separates the electrode from the diaphragm to provide room for vibration of the diaphragm. The vibrating plate is usually thin and light, and thus makes the transient response of the electrostatic speaker, the expiration capability of the high frequency, the smoothness of sound, the acoustic fidelity and the low Distortion is superior to other forms of speakers, such as dynamic, moving coil or piezoelectric speakers. In addition, the vibrating plate must have an electrostatic charge to allow the induced electrostatic force to drive the vibrating plate under the action of the electric field formed by the electrode plate when the signal is transmitted to the electrode plate.

Due to their simple structure, electrostatic speakers can be manufactured in a variety of sizes to accommodate the growing demand for small and thin electronic devices. However, in general, an electrostatic speaker uses a DC-DC converter to provide a static charge on a diaphragm formed by a conductor. Considering the size, cost and power consumption of DC-to-DC power converters, electret materials have been developed to replace DC-to-DC power converters. The electret is a dielectric material having a quasi-permanent charge or dipole polarization. An electret produces internal and external electric fields, which can be an electrostatic equivalent of a permanent magnet, see GM Sessler, 1980, in Topics in Applied Physics vol. 33, Chapter 1, page 1 and US Patent No. 4,288,584 ( Mishra). The electret charge can include a net charge (eg, surface and/or space charge) and/or dipole polarization. The net charge includes capturing positive and negative charge carrier layers.

An exemplary electret speaker is shown in Fig. 1, which may include porous electrode plates 6a and 6b and an electret diaphragm 4. The electrodes 6a and 6b may have some openings 61a and 61b and have at least 30% open porosity on each of the electrode plates. The electrode plates 6a and 6b may be formed of metal or a plastic material covering the conductive film. The openings 61a and 61b can provide passage of sound waves. The electret vibrating plate 4 may include a conductive layer 2 sandwiched between the electret layers 1a and 1b. The electret layers 1a and 1b may include a positive or negative charge or may be positioned to have a relative dipole polarization in the vertical direction of the electret vibrating plate 4. The electrode plates 6a and 6b and the electret vibrating plate 4 can be maintained in place by the supporting members 5a and 5b. The support members 5a and 5b can be made of an insulating material. The electrode plates 6a, 6b can be separated from the electret diaphragm by the insulating members 51a, 51b, 52a and 52b. In the operation of an electret speaker, each of the signal sources 7a and 7b outputs an alternating signal to the electrode plates 6a and 6b via the wires 8a and 8b, respectively. The signal causes a time-varying electric field to develop between the electrode plates 6a and 6b and the electret layers 1a and 1b, and an electrostatic force is generated between the electrode plates 6a and 6b and the electret vibrating plate 4. The electrostatic force can cause the electret vibrating plate 4 to vibrate to generate sound. The generated sound waves can pass through the holes 61a and 61b, so that the sound waves can be heard outside the electret speakers.

However, in order for an electret speaker to enhance its acoustic fidelity and low distortion, it requires an electret material with excellent electret characteristics and a process that requires careful handling to manufacture. A thin electret-metal-electret structure. It is known that electrets can be made from different polymers. An electric charge is generated in the polymer electret film by a continuous current corona treatment. The above different polymers include fluoropolymers, such as poly-tetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP), which can enhance stable residence even under high temperature and high humidity. Polar body characteristics. However, fluoropolymers can be relatively expensive and require specific process technologies. The fluoropolymer surface has a low coefficient of friction, resulting in no grip or stick-slip characteristics. Therefore, these fluoropolymers do not adhere to metals and are not suitable for use in electret speaker systems. An electret vibrating plate. It is also known to make electrets from non-fluoropolymers, such as polystyrene (PS), polycarbonate (PC), polyvinyl chloride (PVC), polymethyl methacrylate ( Polymethylmethacrylate, PMMA) and cyclic olefin copolymer (COC). The use of these non-fluoropolymers described above in the fabrication of electret vibrating plates is much easier than the use of fluoropolymers in the fabrication of electret speakers. However, the initial high surface voltage of the electret made from these non-fluoropolymers drops quite rapidly, especially at high humidity. Therefore, it is necessary to produce a non-fluoropolymer electret whose electret characteristics can be maintained for a long period of time.

A porous ferroelectret film made of polypropylene, which causes a dielectric collapse in each polymer cell during corona charging, is disclosed in U.S. Patent Nos. 4,654,546 and 6,852,402. Dielectric collapse stores the same or different charges on the opposite inner surface of the unit cell. Each cell of a porous iron electret has a space charge that acts like a dipole. Therefore, the porous iron electret acts like a dipole electret with a large dipole moment and a solid-state electret. The body has better electret characteristics.

In the prior art, the pores of the porous iron electret are formed by spontaneous opening of the polymer when the polymer is highly stretched by a polymer containing, for example, fine foreign particles of citrate. The film is stretched simultaneously or sequentially in two perpendicular directions to form a film having a lens-shaped hole. Since the plasma electrons are not sufficiently accelerated to ionize the gas molecules, the pores are often too shallow for efficient charging by internal microplasma discharge. In addition, when a porous iron electret is fabricated using a film stretching technique, film thickness control is also quite difficult.

An embodiment of the present invention provides a method for fabricating an electret film, comprising: providing a polymer-containing solution, the polymer-containing solution comprising at least one polymer material, at least one solvent, and at least one surfactant. Coating the polymer-containing solution to provide a wet polymer film; removing at least a portion of the solvent from the wet polymer film to provide a polymer film; and subjecting the polymer film to a corona charging, To form the electret film.

An embodiment of the present invention provides a speaker, comprising: an audio signal input having a first signal source end and a second signal source end, the audio signal input for receiving an audio signal; and two electrodes are set Separating from each other; and an electret film comprising at least one electret layer and a distal end coupled between the two electrodes. It is noted that one of the two electrodes is coupled to the first signal source, and one of the two electrodes is coupled to the second signal source. The electret film interacts with the first electrode and the second electrode to respond to an audio signal provided by the first signal source and the second signal source. Further, the electret film is vibrated to generate sound. In one embodiment, the electret layer comprises a polymer layer having a plurality of pores and formed from a wet polymer film.

In order to make the invention more apparent and obvious, the following detailed description of the embodiments and the accompanying drawings

In one embodiment of the invention, voids can be created in the non-fluoropolymer film, thereby improving the electret characteristics of the non-fluoropolymer electret film. In an embodiment, the shape of the hole may be spherical like and the inner surface may comprise a partial discharge. An electret speaker can be fabricated from an electret vibrating plate of a non-fluoropolymer electret film. In one embodiment of the present invention, a method of fabricating a porous non-fluoropolymer electret film can be provided.

One embodiment of the invention is directed to a non-fluoropolymer electret film formed from a polymer-containing solution. The polymer-containing solution can include at least one polymeric material and at least one interfacing agent. The polymer material may include one or more cyclic olefin copolymer (COC), polystyrene (PS), polycarbonate (PC), polymethylmethacrylate (PMMA). , polyvinyl chloride (PVC), polyimide (PI), polyetherimide (PEI), high density polyethylene (HDPE) and polypropylene (polypropylene, PP ). The surfactant may include one or more (n+1)-hydroxy-alkanoic acid, (n+1)-aminoalkanoic acid ((n+1)-amino-alkanoic Acid), HO-(CH ₂ ) _n -COOH, 2,3-bis-(n-hydroxy-alkyloxy)-succinic acid, 2,3-bis(n-amino-alkyloxy)-succinic acid, (n+1)-triazolic acid ((n +1)-triazol-alkanoic acid), 2,3-bis(n-triazol-alkyloxy)-succinic acid, dodecane Sodium sulphate (SDS), amphoteric surfactant, nonionic surfactant, anionic surfactant and cationic surfactant. In order to dissolve the polymer material and the surfactant in a solution form, one or more solvents may be added to the polymer-containing solution, such as acetone, tetrahydrofuran (THF), toluene, xylene, and P-xylene, dichloromethane, chloroform, n-methylpyrrolidone (NMP) and dimethylformamide (DMF). Figure 2 shows the molecular formula of a long chain hydrophobic hydrocarbon. The hydrocarbon may have a highly polar carboxylic acid group [-COOH] at one end; at the other end, it may be a hydroxy functional group or an amine functional group, thus generating (n+1)- Hydroxyalkanoic acid or (n+1)-aminoalkanoic acid. In one embodiment of the invention, the mixed polymer solution may comprise a hydroxy acid compound, such as a polymeric material of an 8-hydroxyoctanoic acid interfacial agent and a cyclic olefin copolymer. Specifically, the hydroxy acid compound having a weight concentration of 1-10,000 ppm is soluble in tetrahydrofuran to produce a solution A1. The cyclic olefin copolymer having a weight percentage of 0.1-15 is soluble in a solvent such as toluene, xylene or p-xylene to produce solution B1. In one example, the cycloolefin copolymer can be German TOPAS Cycloolefin copolymer or Arton At least one of the cyclic olefinic copolymers includes, but is not limited to, grades 8007, 6013, 5013, 5017, and 6017. The solutions A1 and B1 are mixed according to a ratio such that the solution A1 is about 0.01 to 30,000 ppm by weight in the resulting mixed polymer solution. In one embodiment, the 8-hydroxyoctanoic acid may have the structure HO-(CH ₂ ) _n -COOH, n=7.

In another embodiment of the present invention, the mixed polymer solution may include a hydroxy acid compound, such as an 8-hydroxyoctanoic acid surfactant, polymerized with polystyrene, polycarbonate, polyvinyl chloride, and polymethyl methacrylate. At least one of the materials. Specifically, 1-10,000 ppm of the hydroxy acid compound can be dissolved in, for example, a dichloromethane or chloroform solution to produce a solution A2. A polymer, such as polystyrene, polycarbonate, polyvinyl chloride or polymethyl methacrylate, is dissolved in a solvent in an amount of 0.1 to 10% by weight to form solutions B2-1, B2-2, B2-3 and B2- 4. In one example, the solvent can be chloroform. The solution A2 may be mixed with the solution B2-1, B2-2, B2-3 or B2-4 in a ratio such that the solution A2 is about 0.01 to 30,000 ppm by weight in the obtained mixed polymer solution.

Figure 3 shows the molecular formula of a long chain hydrophobic hydrocarbon. This hydrocarbon has two highly polar carboxylic acid functional groups [-COOH] at one end; at the other end, it may have a hydroxy functional group or an amine functional group, thus generating 2,3-bis-(n-hydroxy- Alkoxy)succinic acid and 2,3-bis-(n-amino-alkoxy)succinic acid. In another embodiment of the present invention, the mixed polymer solution may include 2,3-bis-(n-hydroxy-alkoxy)succinic acid and 2,3-bis-(n-amino-alkoxy). At least one of them. 1 to 10,000 ppm by weight of 2,3-bis-(n-hydroxy-alkoxy)-succinic acid or 2,3-bis-(n-amino-alkoxy)-succinic acid soluble in solvent Medium to form solution A3. In one embodiment, the solvent can be tetrahydrofuran, dichloromethane or chloroform. The solution A3 may be mixed with B2-1, B2-2, B2-3 or B2-4 in a ratio such that the solution A3 is from about 0.01 to 30,000 ppm by weight in the resulting mixed polymer solution.

In one embodiment, the method of making an electret film using a polymer-containing solution can include the following steps. Will be about 15wt% of Topas The cycloolefin copolymer 8007 pellet was dissolved in a toluene solution (e.g., toluene, Acros, 99%, density about 0.866 g/mL). The above solution was heated to 80 ° C and/or stirred to provide solution A. About 0.01 to 1% by weight of 8-hydroxyoctanoic acid is dissolved in tetrahydrofuran (e.g., tetrahydrofuran, Aldrich, 99%, density about 0.899 g/mL) at room temperature (about 25 ° C) to provide solution B. Solution A and solution B may be mixed in a weight ratio of 95 to 5. In one embodiment, the mixed solution is placed in an agitator for about 10 minutes with an ultrasonic device (such as an ultrasonic mixer or washer) for about 5 minutes to obtain solution C.

Solution C is spin coated onto a copper foil substrate, for example, using a spin coating apparatus, at about 1,500 rpm for about 2 times, about 20 seconds each time, to provide a wet polymer film. The wet polymer film is dried at room temperature or 20 to 25 ° C for about 30 minutes, and may be placed in a vacuum oven (about 0.1 Torr) or an oven at a pressure lower than atmospheric pressure for about 8 hours. Most or all of the solvent or water in the film will evaporate, resulting in a polymer film having pores having an average size of about 1 micron. In one embodiment, the porous polymer film has a thickness of about 8 ± 1 micron.

After the film is formed, a charging process is performed. For example, in one embodiment, a discharge device having a pin plate (bias of -20 KV) is used to form an electret film. The distance between the discharge plate or needle and the film can be approximately 4 cm. In one embodiment, the charging process can be carried out at a temperature of about 20 to 25 ° C and a relative humidity (RH) of about 45 to 50%. Temperature, distance, relative humidity, and discharge bias can be adjusted based on various factors, such as the above parameter values, other external conditions, film materials, thickness or properties, and expected electret characteristics.

In one embodiment, the method of making an electret film using a polymer-containing solution can include the following steps. Will be about 15wt% of Topas The cycloolefin copolymer 8007 pellet was dissolved in a toluene solution (e.g., toluene, Acros, 99%, density about 0.866 g/mL). The above solution was heated to 80 ° C and/or stirred to provide solution A. About 1% by weight of 2-(6-mercaptohexyl)malonic acid is dissolved in tetrahydrofuran (for example, tetrahydrofuran, Aldrich, 99%, at room temperature (about 25 ° C). The density was about 0.899 g/mL) to provide solution B. Solution A and solution B may be mixed in a weight ratio of 90 to 10. In one embodiment, the mixed solution is placed in an agitator for about 10 minutes with an ultrasonic device (such as an ultrasonic mixer or washer) for about 5 minutes to obtain solution C.

Solution C is spin coated onto a copper foil substrate, for example, using a spin coating apparatus, at about 1,500 rpm for about 2 times, about 20 seconds each time, to provide a wet polymer film. The wet polymer film is dried at room temperature or 20 to 25 ° C for about 30 minutes, and may be placed in a vacuum oven (about 0.1 Torr) or an oven at a pressure lower than atmospheric pressure for about 8 hours. Most or all of the solvent or water in the film will evaporate to provide a polymer film having pores having an average size of about 100 nm. In one embodiment, the porous polymer film has a thickness of about 8 ± 1 micron.

After the film is formed, a charging process is performed. For example, in one embodiment, a discharge device having a pin plate (bias of -20 KV) is used to form an electret film. The distance between the discharge plate or needle and the film can be approximately 4 cm. In one embodiment, the charging process can be carried out at a temperature of about 20 to 25 ° C and a relative humidity (RH) of about 45 to 50%. Temperature, distance, relative humidity, and discharge bias can be adjusted based on various factors, such as the above parameter values, other external conditions, film materials, thickness or properties, and expected electret characteristics.

In one embodiment, the method of making an electret film using a polymer-containing solution can include the following steps. Will be about 15wt% of Topas The cycloolefin copolymer 8007 pellet was dissolved in a toluene solution (e.g., toluene, Acros, 99%, density about 0.866 g/mL). The above solution was heated to 80 ° C and/or stirred to provide solution A. About 1% by weight of 2-(10-hydroxydecyl)malonic acid is dissolved in tetrahydrofuran (for example, tetrahydrofuran, Aldrich, 99%, at room temperature (about 25 ° C) The density was about 0.899 g/mL) to provide solution B. Solution A and solution B may be mixed in a weight ratio of 95 to 5. In one embodiment, the mixed solution is placed in an agitator for about 10 minutes with an ultrasonic device (such as an ultrasonic mixer or washer) for about 5 minutes to obtain solution C.

Solution C is spin coated onto a copper foil substrate, for example, using a spin coating apparatus, at about 1,500 rpm for about 2 times, about 20 seconds each time, to provide a wet polymer film. The wet polymer film is dried at room temperature or 20 to 25 ° C for about 30 minutes, and may be placed in a vacuum oven (about 0.1 Torr) or an oven at a pressure lower than atmospheric pressure for about 8 hours. Most or all of the solvent or water in the film will evaporate to provide a polymer film having pores having an average size of about 400 nm. In one embodiment, the porous polymer film has a thickness of about 8 ± 1 micron.

After the film is formed, a charging process is performed. For example, in one embodiment, a discharge device having a pin plate (bias of -20 KV) is used to form an electret film. The distance between the discharge plate or needle and the film can be approximately 4 cm. In one embodiment, the charging process can be carried out at a temperature of about 20 to 25 ° C and a relative humidity (RH) of about 45 to 50%. Temperature, distance, relative humidity, and discharge bias can be adjusted based on various factors, such as the above parameter values, other external conditions, film materials, thickness or properties, and expected electret characteristics.

In one embodiment of the invention, the mixed polymer solution may comprise at least two different polymer solutions. The cyclic olefinic copolymer having a weight percentage of 1-15 can be dissolved in a solvent to form solution A4. Different types of polymeric materials, such as polystyrene, are soluble in the solvent to form solution B4. In an example, the solvent may be at least one of toluene, xylene, and p-xylene. The solutions A4 and B4 were mixed in an appropriate ratio, thereby obtaining a mixed solution. After the drying and corona charge process, it was observed that the surface voltage of the mixed polymer increased compared to the surface voltage of the original polymer. Figure 5 is a graph showing the surface voltage of a cyclic olefin copolymer and a polystyrene mixture. As shown in Fig. 5, the mixed cycloolefin copolymer/polystyrene has a surface voltage of at least 190% in a ratio of 85/15 or 15/85. It has been found that the mixed polymer has a crystalline interface and thus improves charge storage capacity and stability.

In one embodiment, at least one of polycarbonate, polymethyl methacrylate and polyvinyl chloride is soluble in a solvent such as toluene, xylene or p-xylene. Further, at least one of polyethylene and polypropylene is dissolved in p-xylene at a temperature of about 120 ° C, and these solutions are mixed in a suitable ratio, thereby producing a mixed solution. Similar to the above embodiment, in another embodiment, the polymethyleneamine and the polyetherimine are soluble in a solvent such as n-methylpyrrolidone or dimethylformamide, to a suitable one. These solutions are mixed in proportion, thereby producing a mixed solution.

In another embodiment of the invention, the polymer solution referred to in the above examples may include or include a highly polar carboxylic acid [-COOH] to improve the electret properties. In one embodiment, the polymer solution mentioned in the above embodiments may be applied to a non-woven material such as polyethylene (PE), polypropylene (PP), poly pair. Poly(ethylene terephthalate, PET), nylon (nylon), a mixture of polypropylene and nylon or a mixture of polypropylene and polyethylene terephthalate. In an embodiment, the polymer solution may further comprise nano-sized particles or micron-sized fibers. In one example, the particles or fibers may be poly(ethylene terephthalate, PET), polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), At least one of silicon dioxide, aluminum oxide, titanium dioxide, and high density polyethylene.

To form an electret layer, at least a spin coating, a screen-printing, a spray coating, a sputtering, an evaporation, and a scraping technique can be utilized. The mixed solution is applied to a surface or an underlying layer to form a wet polymer film. The wet polymer film is then dried, for example, in a controlled environment or at a controlled temperature. In one embodiment, an environment at a temperature of 20 to 25 ° C can be provided, however, environmental conditions can be varied to control the drying process, such as using an oven as described above. The drying process allows removal of at least a portion of the solvent from the wet polymeric film to provide a polymeric film. In the drying process, the polymer and the highly polar compound form a self-assembling structure with pores ranging from nanometer to micrometer size. In one embodiment, the polymeric film formed by the above process has a plurality of pores having a size between about several nanometers, such as from 10 nanometers to about 10 microns. This configuration increases the electret region of the mixed polymer.

In one embodiment, when the concentration of the surfactant is higher than the critical micelle concentration (CMC), the polymer/interactivator micelles are formed in the polymer-containing solution, and the formed pores are in The dielectric collapse can be maintained during corona charging to improve the electret characteristics of the non-fluoropolymer electret film. In one embodiment, the weight of the polymer material to the interface of the active agent ratio of about 0.01 ~ 10 ⁵ ppm.

In addition, the electret characteristics of the polymer layer or the charge introduced into the polymer layer can be improved by a charging process, such as a corona charging process. A non-fluorine electret film can be formed by the process disclosed above. In one example, the electret characteristics of the cyclic olefin copolymer can be increased to 140%, as shown in FIG. An electret layer can be formed by a roll-to-roll process, such as 1a and 1b in FIG. The electret layer formed has a thickness of about 0.5 to 100 μm.

Referring to Fig. 4, the film 4 comprises two electret layers 1a and 1b and a conductive layer 2 between the electret layers 1a and 1b. The electret layer can be formed using the related processes described above. Conductive layer 2 can be made of gold, silver, aluminum, copper or other electrically conductive material. The conductive layer 2 may be coated on the electret layer 1a by at least one of spray coating, spin coating, sputtering, evaporation, and screen printing to form a structure 3. In one embodiment, the metal layer is evaporated onto the electret layer using an e-beam evaporator. The electret layer 1b is formed on the structure 3 via a vacuum thermal compression, mechanical press or roll-to-roll process to form an electret-metal Electret film. A corona charging process can increase the charge storage stability of the film 4. In this regard, the film 4 can be applied to a vibrating plate such as an electret speaker. In one example, an electrostatic speaker includes a membrane 4 and two electrodes, the electrodes being electrically coupled to an audio signal input. The electrode has an opening to allow sound waves to pass through the opening. The film 4 is sandwiched between the electrodes, and each of the electrodes and the film 4 has an air gap. The membrane 4 can be an actuator coupled to the distal end of the electrode and insulated from the electrode to interact with the electrode, to respond to an audio signal from the audio signal input, and to vibrate to produce an acoustic wave.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope is subject to the definition of the scope of the patent application attached.

1a, 1b. . . Electret layer

2. . . Conductive layer

3. . . structure

4. . . Vibrating plate or film

5a, 5b. . . Support component

51a, 51b, 52a, 52b. . . Insulating element

6a, 6b. . . Porous electrode

61a, 61b. . . Opening

7a, 7b. . . Signal source

8a, 8b. . . wire

Figure 1 is a cross-sectional view of a prior art electret speaker.

Figure 2 is a molecular formula of a hydrophobic hydrocarbon.

Figure 3 is a molecular formula of a hydrophobic hydrocarbon.

Fig. 4 is a partial cross-sectional view showing an electret speaker according to an embodiment of the present invention.

Figure 5 is a graph showing the surface voltage of a mixture of a cyclic olefin copolymer and polystyrene.

Figure 6 is a table showing the surface electricity valence of a cyclic olefin copolymer and a mixed cyclic olefin copolymer in different thicknesses.

1a, 1b. . . Electret layer

2. . . Conductive layer

3. . . structure

4. . . Vibrating plate or film

Claims (33)

A method for producing an electret film, comprising: providing a polymer-containing solution, the polymer-containing solution comprising at least one polymer material and at least one surfactant; applying the polymer-containing solution to provide a Wetting the polymer film; drying the wet polymer film to provide a polymer film; and subjecting the polymer film to a corona charging to form a non-fluoropolymer electret film, wherein the polymer-containing film At least one surfactant of the solution includes (n+1)-hydroxyalkanoic acid ((n+1)-hydroxy-alkanoic acid), (n+1)-aminoalkanoic acid ((n+1)-amino-alkanoic Acid), 2,3-bis(n-hydroxy-alkyloxy)-succinic acid, 2,3-bis-(n-amino group) -2,3-bis(n-amino-alkyloxy)-succinic acid, (n+1)-triazolic acid ((n+1)-triazol-alkanoic acid), 2 , 3-bis-(n-triazol-alkyloxy)-succinic acid, sodium dodecyl sulfate (SDS), Amphoteric surfactant, nonionic surfactant, anionic surfactant and cation At least one interface-active agent. The method for producing an electret film according to claim 1, wherein the weight ratio of the polymer material to the surfactant is from 0.01 to 10 ⁵ ppm. The method for producing an electret film according to claim 1, wherein the concentration of the surfactant is higher than one of the polymer-containing solutions. Critical micelle concentration (CMC). The method for producing an electret film according to claim 1, wherein the coating the polymer-containing solution comprises using spin coating, screen printing, spray coating, sputtering, evaporation, and blade coating. At least one of a scraping process. The method of producing an electret film according to claim 1, further comprising removing at least a portion of the surfactant from the polymer film. The method for manufacturing an electret film according to claim 1, further comprising coupling the electret film and two electrode plates disposed apart from each other, and sandwiching the electret film between the two electrode plates To provide an electret speaker. The method of producing an electret film according to claim 1, wherein the polymer-containing solution comprises a mixed polymer solution comprising at least two polymer materials. The method for producing an electret film according to claim 1, wherein the at least one polymer material of the polymer-containing solution comprises a cyclic olefin copolymer (COC) and a polystyrene. , PS), polycarbonate (PC), polymethylmethacrylate (PMMA), polyvinyl chloride (PVC), polyimide (PI), polyether quinone (polyetherimide, PEI), at least one of high density polyethylene (HDPE) and polypropylene (PP). The manufacturer of the electret film as described in claim 1 The method wherein the polymer-containing solution further comprises at least one solvent. The method for producing an electret film according to claim 9, wherein the solvent comprises acetone, tetrahydrofuran (THF), toluene, xylene, p-xylene. And dichloromethane, chloroform, n-methyl-pyrrolidone (NMP) and at least one of dimethylformamide (DMF). The method for producing an electret film according to claim 1, wherein the polymer film has a plurality of pores ranging in size from 10 nm to 10 μm. A speaker includes: an audio signal input having a first signal source end and a second signal source end, wherein the audio signal input is for receiving an audio signal; the two electrodes are disposed separately from each other, and the two electrodes are An electrode is coupled to the source of the first signal, and a second electrode of the two electrodes is coupled to the source of the second signal; and an electret film including at least one electret layer and coupled at the distal end Between the first electrode and the second electrode, the electret film interacts with the first electrode and the second electrode to respond to the audio provided by the first signal source and the second signal source Signaling and vibrating to produce a sound, wherein the electret layer comprises a non-fluoropolymer layer having a plurality of pores and formed of a polymer-containing solution, wherein the polymer-containing solution comprises at least one polymer material and At least one surfactant, the (n+1)-hydroxy-alkanoic acid (n+1)-amino-alkanoic acid, (n+1)-aminoalkanoic acid ((n+1) )-amino-alkanoic acid), 2,3- Bis-(n-hydroxy-alkyloxy)-succinic acid, 2,3-bis-(n-amino-alkoxy)-amber Acid (2,3-bis(n-amino-alkyloxy)-succinic acid), (n+1)-triazolic acid ((n+1)-triazol-alkanoic acid), 2,3-bis-(n -3,3-bis(n-triazol-alkyloxy)-succinic acid, sodium dodecyl sulfate (SDS), amphoteric surfactant, nonionic At least one of a type of surfactant, an anionic surfactant, and a cationic surfactant. The speaker of claim 12, wherein the polymer-containing solution comprises a mixed polymer solution comprising at least two polymeric materials. The speaker according to claim 12, wherein the polymer-containing solution comprises a cyclic olefin copolymer (COC), a polystyrene (PS), a polycarbonate (polycarbonate, PC). , polymethylmethacrylate (PMMA), polyvinyl chloride (PVC), polyimide (PI), polyetherimide (PEI), high density polyethylene (high Density polyethylene, HDPE) and at least one of polypropylene (PP). The speaker of claim 12, wherein the polymer-containing solution further comprises at least one solvent. The speaker according to claim 15, wherein the solvent comprises acetone, tetrahydrofuran (THF), toluene, xylene, p-xylene, methylene chloride. At least one of (dichloromethane), chloroform, n-methyl-pyrrolidone (NMP) and dimethylformamide (DMF). The speaker of claim 12, wherein the holes have a size ranging from nanometers to micrometers. The speaker of claim 12, wherein the electret film further comprises a conductive layer, wherein the electret layer is formed on at least one side of the conductive layer. The speaker of claim 12, wherein the electret layer is at least one of a spray coating, a spin coating, a sputtering, an evaporation, a screen printing, and a scraping process. One is formed on a lower layer. The speaker of claim 12, wherein the electret film is an actuator distally coupled to the electrode and insulated from the electrode to cause the actuator to vibrate relative to the electrode. The speaker of claim 12, wherein the electret film is sandwiched between the first and second electrodes, and between the first electrode and the second electrode and the electret film Both have air gaps. The speaker of claim 12, wherein the electret film comprises a metal film sandwiched between the two electret layers. The speaker of claim 12, wherein at least one of the first and second electrodes has an opening to allow the sound to pass through the opening. The speaker of claim 12, wherein the electret film comprises a nonwoven material on which an electret layer is formed. The speaker of claim 24, wherein the non-woven material comprises at least one of polyethylene, polypropylene, poly(ethylene terephthalate, PET) and nylon. The speaker of claim 12, wherein the electret layer comprises at least one of a nano-sized particle and a micron-sized fiber. The speaker according to claim 26, wherein at least one of the nano-sized particles and the micro-sized fibers comprises polyethylene terephthalate, poly-tetrafluoroethylene (PTFE), and fluorinated B. At least one of fluorinated ethylene propylene (FEP), silicon dioxide, titanium dioxide, aluminum oxide and high density polyethylene. The method for producing an electret film according to claim 1, wherein the at least one surfactant of the polymer-containing solution comprises at least one hydrocarbon having the molecular formula Y-(CH ₂ ) _n -COOH, Wherein Y is OH, NH ₂ or SH, and n is between 5 and 10. The method for producing an electret film according to claim 1, wherein the at least one surfactant of the polymer-containing solution comprises at least one hydrocarbon having the molecular formula Y-(CH ₂ ) _n -CH ( COOH) ₂ , wherein Y is OH, NH ₂ or SH, and n is between 5 and 10. The method for producing an electret film according to claim 1, wherein the at least one surfactant of the polymer-containing solution comprises 2-(6-thiolhexyl)malonic acid (2-(6-) Mercaptohexyl)malonic acid). The speaker according to claim 12, wherein the polymer-containing solution comprises at least one hydrocarbon having the formula Y-(CH ₂ ) _n -COOH, wherein Y is OH, NH ₂ or SH, n At 5~10. The speaker according to claim 12, wherein the polymer-containing solution comprises at least one hydrocarbon having the formula Y-(CH ₂ ) _n -CH(COOH) ₂ , wherein Y is OH, NH ₂ or SH, n is between 5 and 10. The speaker of claim 12, wherein the polymer-containing solution comprises 2-(6-mercaptohexyl)malonic acid.