TWI473505B - Packages for electret electroacoustic transducers - Google Patents

Description

Encapsulation structure of electret electroacoustic conversion device

The present invention relates to an electret electroacoustic conversion device, and more particularly to a package structure of an electret electroacoustic conversion device.

Traditional loudspeakers are mainly divided into moving coil speakers, piezoelectric speakers and electrostatic speakers. The moving coil type speaker mainly uses the interaction of the magnetic field, the current and the force at right angles to control the piston-type repetitive motion of the diaphragm, and the volume cannot be reduced, so that it cannot meet the demand for thinning and thinning of the future 3C products.

Piezoelectric speakers use the piezoelectric effect. When an electric field is applied to the piezoelectric material, the piezoelectric material is deformed and the diaphragm is excited. However, the resonant frequency required for the piezoelectric material is high and the available bandwidth is insufficient. Therefore, the applicable fields are limited.

The principle of the electrostatic speaker is to hold a conductive diaphragm between two electrode plates with openings to form a capacitor-like structure, by supplying a DC bias to the conductive diaphragm, and supplying the two electrodes simultaneously to synchronize the positive and negative phases. The alternating voltage is transmitted through the electrostatic force generated by the positive and negative charges to drive the conductive diaphragm and radiate the sound. The conductive diaphragm used in the electrostatic speaker is extremely thin and light, and has the advantages of fast transient response, high resolution, low distortion, and immunity from electromagnetic influence.

Electret electroacoustic transducers are generally applicable to electrostatic speakers. After the electret diaphragm element is used for charging, it can maintain a high positive and negative or the same positive or negative bias for a long time, and the audio amplifier only needs to output a small AC audio voltage value to achieve high Quality sound field effect. Therefore, the electret electro-acoustic converter not only meets the requirements of lighter and lighter quality in the future market, but also has the advantages of power saving and cost saving.

In view of the above, one of the objects of the embodiments of the present invention is to provide a package structure of an electret electroacoustic conversion device that is substantially free of bonding agents, in order to meet the requirements of lightness and high sound quality.

According to an embodiment of the present invention, a package structure of an electret electroacoustic conversion device is provided, including: a first electrode mesh; a double-layer electret diaphragm disposed opposite the first electrode mesh, wherein the double-layer resident A metal plating layer is interposed between the polar body diaphragms to form a laminated electret diaphragm structure; a first isolation structure is disposed between the first electrode mesh and the double layer electret diaphragm; the second electrode mesh a second isolation structure disposed between the double-layer electret diaphragm and the second electrode mesh; and first and second outer frames, the first An isolation structure, the first electrode mesh, the double-layer electret diaphragm, the second isolation structure, and the second electrode mesh are sandwiched therebetween.

In order to make the present invention more apparent, the following detailed description of the embodiments and the accompanying drawings are set forth below.

The following is a detailed description of the embodiments and examples accompanying the drawings, which are the basis of the present invention. In the drawings or the description of the specification, the same drawing numbers are used for similar or identical parts. In the drawings, the shape or thickness of the embodiment may be expanded and simplified or conveniently indicated. In addition, the components of the drawings will be described separately, and it is noted that the components not shown or described in the drawings are known to those of ordinary skill in the art, and in particular, The examples are merely illustrative of specific ways of using the invention and are not intended to limit the invention.

1 shows an exploded schematic view of a package structure of an electret electroacoustic conversion device according to an embodiment of the present invention. Referring to FIG. 1, the package structure of the electret electroacoustic conversion device includes a first electrode mesh 120. The double-layer electret diaphragm 140 is disposed opposite to the first electrode mesh 120, wherein the double-layer electret diaphragm has an aluminum plating layer (not shown) interposed between the two electret diaphragms 142 and 144. Or other metal plating to form a laminated electret diaphragm structure. The first isolation structure 130 is disposed between the first electrode film 120 and the double layer electret diaphragm 140. The second electrode mesh 125 is disposed opposite the double-layer electret diaphragm. The second isolation structure 135 is disposed between the double-layer electret diaphragm 140 and the second electrode mesh 125. The first and second outer frames 110 and 115 sandwich the first isolation structure 130, the first electrode mesh 120, the double-layer electret diaphragm 140, the second isolation structure 135, and the second electrode mesh 125. In the meantime. The package structure of the assembled electret electroacoustic conversion device is shown in FIG. 2 .

During operation, an in-phase or reverse-phase AC audio voltage output by an AC power source (eg, an audio amplifier), an AC bias applied between the first electrode mesh 120 and the second electrode mesh 125 provides driving of the electret diaphragm The electric field of vibration.

According to an embodiment of the invention, the first and second outer frames 110, 115 are rigid or rigid injection molded plastic. The outer shapes of the first and second outer frames 110, 115 may be a class-like pane structure having a plurality of latches 150 in the peripheral region, as shown in FIG. In an embodiment, the first outer frame 110 has a convex portion 160a around the periphery, and the second outer frame 115 has a corresponding concave portion 160b around the second outer frame 115. The corresponding concave portion of the protruding portion is fitted to each other, as shown in FIG. 4A. Show. In another embodiment, the first and second outer frames 110, 115 are coupled by a cassette 170, as shown in FIG. 4B.

The electret diaphragm 140 is made of an electret material and maintains a high bias voltage on the surface for a long time after charging. In particular, an electret material refers to a static charge that can be retained for a long time after undergoing electrification treatment of a dielectric material. The electret material constituting the electret diaphragm 140 may be a fluorine-containing polymer material, and fluorine has the strongest electrical property. Therefore, the charge of the electret diaphragm structure 140 can be charged. The electret material is preferably a fluorine-containing organic polymer material or a fluorine-containing organic inorganic polymer. The fluorine-containing polymer material includes expanded polytetrafluoroethylene (ePTFE), side-chained polytetrafluoroethylene (PFA), fluorinated ethylene propylene (FEP), and ethylene-tetrafluoroethylene polymer ( ETFE), and ethylene-trifluoroethylene (ECTFE) copolymer.

The purpose of the first and second isolation structures 130, 135 is to separate the electret diaphragm structure from the electrode mesh and to create an electrical insulating effect. The first and second isolation structures 130, 135 can be selected to be injection molded or stamped to separate the electret diaphragm structure 140 into a plurality of regions.

Compared with the conventional electret electroacoustic conversion device, the electret electroacoustic conversion device package structure of the above embodiment of the present invention has the following advantages:

1. Traditional electret electrostatic speakers (EFL) use adhesive tape to bond the main components. After a long period of operation and environmental degradation, the adhesive tape is aged to affect the sound quality of the electret electrostatic speaker. The present invention has significantly improved the aging phenomenon of electret electrostatic speaker (EFL) products by using injection molded plastic materials in the joint members and replacing the conventional use of adhesive tape.

2. The metal mesh electrode used in the embodiment of the present invention has a sound quality distortion due to surface roughness, and the sound effect of a planar electrode cannot be achieved even if it is fixed by an adhesive tape. From a physical point of view, the distance between the electret and the electrode with a rough surface is not uniform. When a high voltage is applied to generate an electric field between the electret and the electrode, the force on the push-pull of the diaphragm is unbalanced, and the sound of the high-pitched sound becomes a big problem. With the design of the injection molded plastic of the present invention, the distance between the electret diaphragm and the electrode can be easily supported and fixed, so that the electret electrostatic speaker (EFL) maintains high quality output, reduces noise and maintains low. Distortion.

3. Traditional electret electrostatic speakers (EFL) are assembled by hand, which are inefficient and the quality cannot be maintained. With the design of the injection molded plastic of the present invention, the conventional electret electrostatic speaker (EFL) can be manufactured by automated production, which significantly reduces human error and improves manufacturing efficiency.

The present invention has been disclosed in the above various embodiments, and is not intended to limit the scope of the present invention. Any one of ordinary skill in the art can make a few changes and refinements without departing from the spirit and scope of the invention. . The scope of the invention is defined by the scope of the appended claims.

110. . . First outer frame

115. . . Second outer frame

120. . . First electrode network

125. . . Second electrode net

130. . . First isolation structure

135. . . Second isolation structure

140. . . Double layer electret diaphragm

142, 144. . . Electret material

150. . . Latch

160a. . . Protrusion

160b. . . Concave

170. . . Latch

1 shows an exploded schematic view of a package structure of an electret electroacoustic conversion device according to an embodiment of the present invention.

2 is a schematic view showing a package structure of an electret electroacoustic conversion device assembled according to an embodiment of the present invention.

3 shows a schematic view of a structure having a plurality of peripheral regions that are snapped onto the outer frame in accordance with an embodiment of the present invention.

4A and 4B are schematic views showing the engagement of an exception frame in accordance with the present invention.

110. . . First outer frame

115. . . Second outer frame

120. . . First electrode network

125. . . Second electrode net

130. . . First isolation structure

135. . . Second isolation structure

140. . . Double layer electret diaphragm

142, 144. . . Electret material

Claims (7)

The package structure of an electret electroacoustic conversion device includes: a first electrode mesh; a double-layer electret diaphragm disposed opposite to the first electrode mesh, wherein the double-layer electret diaphragm is interposed a metal plating layer forms a laminated electret diaphragm structure; a first isolation structure is disposed between the first electrode mesh and the double layer electret diaphragm; a second electrode mesh, and the double layer electret The diaphragm is disposed opposite to each other; the second isolation structure is disposed between the double layer electret diaphragm and the second electrode; and the first and second outer frames, the first electrode net, the first isolation structure The double-layer electret diaphragm, the second isolation structure, and the second electrode mesh are interposed therebetween. The package structure of the electret electroacoustic conversion device according to claim 1, wherein the first and second isolation structures are injection molded plastic. The package structure of the electret electroacoustic conversion device according to claim 1, wherein the first outer frame has a convex portion around the second outer frame, and the second outer frame has a corresponding concave portion around the second outer frame. The corresponding concave portions of the portions are fitted to each other. The package structure of the electret electroacoustic conversion device according to claim 1, wherein the first and second outer frames are coupled by a cassette. An electret electroacoustic conversion device as described in claim 1 The package structure, wherein the double-layer electret diaphragm comprises fluorine containing polymers. The package structure of the electret electroacoustic conversion device according to claim 5, wherein the fluorine-containing polymer material comprises expanded polytetrafluoroethylene (ePTFE) and side chain polytetrafluoroethylene (PFA). , fluorinated ethylene propylene (FEP), ethylene-tetrafluoroethylene polymer (ETFE), and ethylene-trifluoroethylene (ECTFE) copolymer. The package structure of the electret electroacoustic conversion device according to claim 1, wherein the first isolation structure, the first electrode mesh, the double-layer electret diaphragm, the second isolation structure and the first The two-electrode network is mechanically bonded with virtually no binder between them.