Conductive diaphragm and loudspeaker

Abstract

The invention provides a conductive diaphragm and a loudspeaker. The conductive vibrating diaphragm comprises a main body layer and a conductive layer arranged on the main body layer, the conductive layer comprises an elastic matrix and a conductive filler dispersed in the elastic matrix, and the conductive layer comprises the following components in parts by mass: 8-20 parts of the elastic matrix, 76-95 parts of the conductive filler and 0.1-3 parts of a modifier. The conductive filler comprises a nano metal conductive filler and a micro-nano conductive filler. Compared with the prior art, the conductive layer of the conductive vibrating diaphragm adopts the elastomer with good high and low temperature modulus stability as the elastic matrix, the nano metal conductive filler with the melting point lower than 200 DEG C is blended with the micro-nano conductive filler to serve as the conductive functional body, and the conductive functional bodies in the conductive layer are welded together; and the elastic matrix can effectively avoid the problems of sudden rigidity change, poor material toughness and the like of the conductive vibrating diaphragm, so that both conductivity and smoothness are realized.

Description

Technical Field

[0001] The present invention relates to the field of electroacoustic conversion, and in particular to a conductive diaphragm and a loudspeaker. Background Art

[0002] A speaker typically consists of a diaphragm, a voice coil, and a conductive circuit connecting the voice coil to an external circuit. The voice coil leads are typically spot-welded to the pads of the external conductive circuit, allowing the speaker to generate sound through electrical signals. However, when connecting the pads to the voice coil leads, high-frequency vibrations and stress concentration can cause the voice coil leads to break, leading to speaker failure. In existing speakers, adding an FPC (flexible printed circuit) as an external circuit connection can partially address the issue of voice coil wire breakage, but this takes up space inside the speaker and compromises performance. Creating a conductive layer on the diaphragm surface not only effectively addresses the voice coil breakage issue, but also eliminates the need for internal speaker space, significantly improving the speaker's reliability and acoustic performance.

[0003] The conductive circuit layer on the diaphragm surface can be created by spraying or printing a conductive layer. The conductive layer is primarily composed of a resin matrix and a conductive material. The conductive layer is formed by filling it with conductive particles so that they contact each other to form a conductive path. To reduce the resistance of the conductive layer, it is often necessary to increase the mass percentage of the conductive material in the polymer matrix. However, increasing the mass percentage of the conductive material reduces the toughness of the diaphragm, and the conductive path formed by the added conductive material is unstable. When the material is stretched or strained, the resistance of the conductive layer increases significantly, failing to meet the conductivity requirements of the conductive diaphragm.

[0004] There are two existing approaches to addressing this issue. One involves compounding conductive particles of different types or sizes, filling nanosized fillers between micrometer-sized conductive fillers, and utilizing the tunneling effect to create a low-resistivity conductive layer. However, this conductive layer still fails to address the sharp increase in resistance during diaphragm vibration, i.e., when the material is stretched. The other approach involves adding a large amount of nanosilver wire to reduce the resistance change under stretching. This approach is not only very expensive, but also involves severe deformation of the conductive layer during the hot pressing process, which can easily cause the conductive layer to break and significantly increase speaker distortion.

[0005] Therefore, how to solve the problem of a significant increase in resistance during the vibration of the conductive layer and prevent the conductive layer from affecting the vibration and sound of the diaphragm and reducing the sound quality is an urgent problem to be solved. It is necessary to provide a new conductive diaphragm and speaker to solve the above technical problems. Summary of the Invention

[0006] The object of the present invention is to provide a conductive diaphragm and a loudspeaker that have both good conductivity and smoothness.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a conductive diaphragm, comprising a main body layer and a conductive layer disposed on a surface of the main body layer, wherein the conductive layer comprises an elastic matrix and conductive fillers dispersed in the elastic matrix; The components of the conductive layer include, by mass ratio: 8-20 parts of the elastic matrix, 76-95 parts of the conductive filler, and 0.1-3 parts of the modifier; The conductive filler includes nano-metal conductive filler and micro-nano conductive filler; The diameter of the nano-metal conductive filler is 3-40 nm, and the diameter of the micro-nano conductive filler is 0.2-9 μm; The weight ratio of the nano-metal conductive filler to the micro-nano conductive filler is 0.3:10 - 6:10; The melting point of the nano-metal conductive filler is lower than 200°C.

[0008] Preferably, the initial resistivity of the conductive layer is The elastic modulus of the conductive layer is 5-400 MPa, and the elongation at break of the conductive layer is greater than 100%; when the strain of the conductive diaphragm is ≤25%, the resistance change rate of the conductive diaphragm is ≤450%.

[0009] Preferably, the nano-metal conductive filler includes one or more of silver, gold, copper, aluminum, nickel, vanadium, indium and palladium.

[0010] Preferably, the shape of the micro-nano conductive filler includes one or more of spherical, quasi-spherical, flake, dendritic and rod-shaped.

[0011] Preferably, the micro-nano conductive filler includes one or more of a metal material, a surface-plated metal material, and a conductive carbon material.

[0012] Preferably, the metal material includes one or more of silver, gold, copper, aluminum, nickel, vanadium, indium and palladium.

[0013] Preferably, the surface metal plating material includes one or more of silver-coated copper and silver-plated polymer particles.

[0014] Preferably, the conductive carbon material includes one or more of carbon black, graphene and carbon nanotubes.

[0015] Preferably, the elastic matrix comprises one or more of silicone elastomer, acrylate rubber, ethylene acrylate rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, ethylene propylene rubber and thermoplastic elastomer.

[0016] Preferably, the modifier includes one or more of a leveling agent, a defoaming agent, a conductive promoter, a thixotropic agent, and a dispersant.

[0017] Preferably, the conductive layer is formed on the surface of one side or the surfaces of two opposite sides of the main layer and completely covers the surface of the main layer; or the conductive layer is at least partially embedded in one side of the main layer.

[0018] Preferably, the conductive layer is coated or adhered to the main body layer, or the conductive layer and the main body layer are integrally injection molded.

[0019] In a second aspect, the present invention further provides a loudspeaker comprising the conductive diaphragm according to any one of the above embodiments.

[0020] Compared with the prior art, the conductive layer of the conductive diaphragm of the present invention adopts an elastomer with good high and low temperature modulus stability as the elastic matrix, blends nano-metal conductive fillers with micro-nano conductive fillers with a melting point below 200°C as the conductive functional body, and compounded the conductive functional body with a modifier to prepare a stretchable conductive slurry. When the nano-metal conductive filler in the conductive slurry evaporates or partially melts during the volatilization process, the various conductive functional bodies in the conductive layer are welded to form a stable conductive network. The elastic matrix with good high and low temperature modulus stability can effectively avoid problems such as sudden changes in the rigidity of the conductive diaphragm and poor material toughness, thereby achieving a balance between conductivity and smoothness. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which: Figure 1 Schematic diagram of the structure of the conductive diaphragm provided in an embodiment of the present invention Figure 1 ; Figure 2 Schematic diagram of the structure of the conductive diaphragm provided in an embodiment of the present invention Figure 2 ; Figure 3 Schematic diagram of the structure of the conductive diaphragm provided in an embodiment of the present invention Figure 3 .

[0022] In the figure, 100 is a conductive diaphragm, 101 is a main layer, and 102 is a conductive layer. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Combine Figure 1-Figure 3 As shown, the present invention provides a conductive diaphragm 100, the conductive diaphragm 100 includes a main body layer 101 and a conductive layer 102 provided on the surface of the main body layer 101, the conductive layer 102 includes an elastic matrix and conductive fillers dispersed in the elastic matrix; The components of the conductive layer 102 are as follows by mass ratio: 8-20 parts of the elastic matrix, 76-95 parts of the conductive filler, and 0.1-3 parts of the modifier; The initial resistivity of the conductive layer 102 is The elastic modulus of the conductive layer 102 is 5-400 MPa, and the elongation at break of the conductive layer 102 is greater than 100%; when the strain of the conductive diaphragm 100 is less than or equal to 25%, the resistance change rate of the conductive diaphragm 100 is less than or equal to 450%.

[0025] In the present invention, the conductive filler includes nano-metal conductive filler and micro-nano conductive filler; The diameter of the nano-metal conductive filler is 3-40 nm, and the diameter of the micro-nano conductive filler is 0.2-9 μm; The weight ratio of the nano-metal conductive filler to the micro-nano conductive filler is 0.3:10-6:10.

[0026] In the present invention, the nano-metal conductive filler includes one or more of silver, gold, copper, aluminum, nickel, vanadium, indium and palladium.

[0027] In the present invention, the melting point of the nano-metal conductive filler is lower than 200°C.

[0028] In the present invention, the shape of the micro-nano conductive filler includes one or more of spherical, quasi-spherical, flake, dendritic and rod-like.

[0029] In the present invention, the micro-nano conductive filler includes one or more of a metal material, a surface-plated metal material, and a conductive carbon material.

[0030] In the present invention, the metal material includes one or more of silver, gold, copper, aluminum, nickel, vanadium, indium and palladium.

[0031] In the present invention, the surface metal plating material includes one or more of silver-coated copper and silver-plated polymer particles.

[0032] In the present invention, the conductive carbon material includes one or more of carbon black, graphene and carbon nanotubes.

[0033] In the present invention, the elastic matrix includes one or more of silicone elastomer, acrylic rubber, ethylene acrylic rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, ethylene propylene rubber and thermoplastic elastomer.

[0034] In the present invention, the modifier includes one or more of a leveling agent, a defoaming agent, a conductive promoter, a thixotropic agent, and a dispersant.

[0035] In the present invention, the conductive layer 102 is formed on one side or two opposite sides of the main body layer 101 and completely covers the surface of the main body layer 101; or the conductive layer 102 is at least partially embedded in one side of the main body layer 101. In another optional embodiment, the conductive layer 102 is coated or adhered to the main body layer 101, or the conductive layer 102 and the main body layer 101 are integrally injection molded.

[0036] Compared with the prior art, the conductive layer of the conductive diaphragm of the present invention adopts an elastomer with good high and low temperature modulus stability as the elastic matrix, blends nano-metal conductive fillers with micro-nano conductive fillers with a melting point below 200°C as the conductive functional body, and compounded the conductive functional body with a modifier to prepare a stretchable conductive slurry. When the nano-metal conductive filler in the conductive slurry evaporates or partially melts during the volatilization process, the various conductive functional bodies in the conductive layer are welded to form a stable conductive network. The elastic matrix with good high and low temperature modulus stability can effectively avoid the problems of sudden change in the rigidity of the conductive diaphragm, poor material toughness, etc., reduce the resistance change of the diaphragm in the stretched state, thereby achieving a balance between conductivity and smoothness.

[0037] In the present invention, in order to better reflect the performance test of the conductive diaphragm 100 of the present invention, the following Example 1, Example 2, and Comparative Example are specially prepared to obtain measurement results for display.

[0038] Example 1 Preparation process of conductive diaphragm: add 15 parts of butyl rubber to 40 parts of ethylene glycol butyl ether, stir at high speed to dissolve, then add 0.8 parts of leveling agent BYK-410, 0.5 parts of dispersant BYK-110, 0.5 parts of thixotropic agent BYK-607, 10 parts of nano silver powder (particle size D50 15nm, nano metal conductive filler), 75 parts of flaky silver powder (D50 3μm, micro-nano conductive filler) in sequence and stir thoroughly to form a mixed slurry; then stir the mixed slurry evenly with a double planetary mixer, and finally disperse and degas at high speed to obtain a conductive silver paste with a viscosity of 10300cps; transfer the silver paste to the diaphragm by screen printing or diluted inkjet printing (including aerosol jet printing), and then bake at 150℃ for 15min, with a thickness of 50±2μm, and cut into Spline, testing the resistance change before and after the diaphragm is stretched.

[0039] Example 2 Preparation process of conductive diaphragm: add 15 parts of butyl rubber to 40 parts of ethylene glycol butyl ether, stir at high speed to dissolve, then add 0.8 parts of leveling agent BYK-410, 0.5 parts of dispersant BYK-110, 0.5 parts of thixotropic agent BYK-607, 15 parts of nano silver powder (particle size D50 15nm), 70 parts of flake silver powder (D50 3μm) in sequence and stir thoroughly to form a mixed slurry; then stir the mixed slurry evenly with a double planetary mixer, and finally disperse and degas at high speed to obtain a conductive silver paste with a viscosity of 9850cps; transfer the silver paste to the diaphragm by screen printing or diluted inkjet printing (including aerosol jet printing), and then bake at 150℃ for 15min. The sample thickness is 50±2μm and cut into Spline, testing the resistance change before and after the diaphragm is stretched.

[0040] Comparative Example Preparation process of conductive diaphragm: add 15 parts of polyester elastomer to 40 parts of ethylene glycol butyl ether, stir at high speed to dissolve, then add 0.8 parts of leveling agent BYK-410, 0.5 parts of dispersant BYK-110, 0.5 parts of thixotropic agent BYK-607, 15 parts of nano silver powder (particle size D50 300nm), 70 parts of flake silver powder (D50 3μm) in sequence and stir thoroughly to form a mixed slurry; then stir the mixed slurry evenly with a double planetary mixer, and finally disperse and degas at high speed to obtain a conductive silver paste with a viscosity of 14060cps; transfer the silver paste to the diaphragm by screen printing or diluted inkjet printing (including aerosol jet printing), and then bake at 150℃ for 15min. The sample thickness is 50±2μm and cut into Spline, testing the resistance change before and after the diaphragm is stretched.

[0041] The performance test results of the conductive diaphragms of Example 1 to the comparative example are as follows:

[0042] Performance test results show that controlling the nanosilver powder particle size within a range (3-40nm) can effectively reduce the resistance change rate after stretching the resistor. This means that the conductive diaphragm 100 proposed by the present invention can control the resistance change rate even when the resistor is stretched, resulting in superior performance.

[0043] Example 3 An embodiment of the present invention further provides a loudspeaker, which includes the conductive diaphragm as described in the above-mentioned embodiment 1 and embodiment 2, and the loudspeaker can achieve the technical effects described in the above-mentioned embodiment 1 and embodiment 2, which will not be repeated here.

[0044] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. A conductive diaphragm, characterized in that: The conductive diaphragm includes a main body layer and a conductive layer formed on the surface of the main body layer, and the conductive layer includes an elastic matrix and conductive fillers dispersed in the elastic matrix; The components of the conductive layer include, by mass ratio: 8-20 parts of the elastic matrix, 76-95 parts of the conductive filler, and 0.1-3 parts of the modifier; The conductive filler includes a nano-metal conductive filler and a micro-nano conductive filler; the diameter of the nano-metal conductive filler is 3-40 nm, and the diameter of the micro-nano conductive filler is 0.2-9 μm; the weight ratio of the nano-metal conductive filler to the micro-nano conductive filler is 0.3:10-6:10; The melting point of the nano-metal conductive filler is lower than 200°C.

2. The conductive diaphragm according to claim 1, wherein: The initial resistivity of the conductive layer is The elastic modulus of the conductive layer is 5-400 MPa, and the elongation at break of the conductive layer is greater than 100%; when the strain of the conductive diaphragm is ≤25%, the resistance change rate of the conductive diaphragm is ≤450%.

3. The conductive diaphragm according to claim 1, wherein: The nano-metal conductive filler includes one or more of silver, gold, copper, aluminum, nickel, vanadium, indium and palladium.

4. The conductive diaphragm according to claim 1, wherein: The shape of the micro-nano conductive filler includes one or more of spherical, quasi-spherical, flake, dendritic and rod-like.

5. The conductive diaphragm according to claim 1, wherein: The micro-nano conductive filler includes one or more of a metal material, a surface-plated metal material, and a conductive carbon material.

6. The conductive diaphragm according to claim 5, characterized in that: The metal material includes one or more of silver, gold, copper, aluminum, nickel, vanadium, indium and palladium.

7. The conductive diaphragm according to claim 5, wherein: The surface metal plating material includes one or more of silver-coated copper and silver-plated polymer particles.

8. The conductive diaphragm according to claim 5, wherein: The conductive carbon material includes one or more of carbon black, graphene and carbon nanotubes.

9. The conductive diaphragm according to claim 1, wherein: The elastic matrix includes one or more of silicone elastomer, acrylic rubber, ethylene acrylic rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, ethylene propylene rubber and thermoplastic elastomer.

10. The conductive diaphragm according to claim 1, wherein: The modifier includes one or more of a leveling agent, a defoaming agent, a conductive promoter, a thixotropic agent, and a dispersant.

11. The conductive diaphragm according to claim 1, wherein: The conductive layer is formed on the surface of one side or the surfaces of two opposite sides of the main layer and completely covers the surface of the main layer; or the conductive layer is at least partially embedded in one side of the main layer.

12. The conductive diaphragm according to claim 11, wherein: The conductive layer is coated or adhered to the main body layer, or the conductive layer and the main body layer are integrally injection-molded.

13. A speaker, characterized in that: The loudspeaker comprises the conductive diaphragm according to any one of claims 1-12.

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