阅读说明：本技术 振动板和发声装置 (Vibrating plate and sound generating device ) 是由 王述强 惠冰 凌风光 李春 于 2020-05-20 设计创作，主要内容包括：本发明公开一种振动板和发声装置。其中,所述振动板包括至少一层复合纤维层,所述复合纤维层中的复合纤维包括聚醚酰亚胺纤维和碳纤维。本发明的技术方案能够保证发声装置在较大使用功率下具有较好的发声效果。(The invention discloses a vibrating plate and a sound generating device. The vibrating plate comprises at least one composite fiber layer, wherein the composite fibers in the composite fiber layer comprise polyetherimide fibers and carbon fibers. The technical scheme of the invention can ensure that the sound generating device has better sound generating effect under larger service power.)

1. The vibrating plate is applied to a sound generating device and is characterized by comprising at least one composite fiber layer, wherein composite fibers in the composite fiber layer comprise polyetherimide fibers and carbon fibers.

2. The vibration plate of claim 1 wherein the polyetherimide fiber has a modulus in the range of 1GPa to 9 GPa.

3. A vibrating plate according to claim 1, wherein the polyetherimide fiber has a glass transition temperature in a range of 200 ℃ to 260 ℃.

4. The vibrating plate according to claim 1, wherein a content of the carbon fiber is 5% to 90% by mass of the polyetherimide fiber.

5. A vibrating plate according to claim 1, wherein the carbon fiber is a staple fiber, and a length of the staple fiber ranges from 0.5mm to 20 mm; and/or the presence of a gas in the gas,

the modulus of the carbon fiber ranges from 100GPa to 500 GPa.

6. A vibrating plate according to any one of claims 1 to 5, wherein the composite fiber layer has a density in the range of 0.3g/cm³To 1.2g/cm³(ii) a And/or the presence of a gas in the gas,

the thickness of the composite fiber layer ranges from 50 μm to 1500 μm.

7. The vibration plate according to any one of claims 1 to 5, wherein an elastic modulus of the vibration plate is in a range of 2GPa to 40 GPa.

8. A vibrating plate according to any one of claims 1 to 5, wherein the composite fibers further comprise a binder fiber selected from at least one of polyvinyl alcohol fibers, polyethylene fibers, polyamide nitrile fibers, and polyvinyl chloride fibers.

9. The vibrating plate according to claim 8, wherein the content of the binder fiber is 1 to 20% by mass of the polyetherimide fiber.

10. A vibration plate according to any of claims 1 to 5, further comprising at least one of a rubber film layer, a polymer film layer, and a thermoplastic elastomer layer, wherein adjacent two layers are bonded by adhesive or thermocompression.

11. A vibration plate according to claim 10, wherein when the vibration plate includes a film layer, the film layer is made of at least one material selected from the group consisting of acrylic glue, epoxy glue, and silicone glue; and/or the presence of a gas in the gas,

when the vibrating plate comprises a rubber film layer, the material of the rubber film layer is selected from at least one of nitrile rubber, hydrogenated nitrile rubber, ethylene propylene diene monomer, butyl rubber, ethylene-acrylic acid rubber, acrylate rubber, natural rubber, styrene butadiene rubber and styrene butadiene rubber; and/or the presence of a gas in the gas,

when the vibrating plate comprises a polymer film layer, the material of the polymer film layer is selected from at least one of polypropylene, polyethylene terephthalate, polyether ether ketone, polyarylate, polyamide, liquid crystal polymer, polyetherimide and polyimide; and/or the presence of a gas in the gas,

when the vibration plate includes the thermoplastic elastomer layer, the material of the thermoplastic elastomer layer is at least one selected from the group consisting of a thermoplastic polyurethane elastomer and a thermoplastic polyester elastomer.

12. A sound-emitting device characterized by comprising the vibration plate according to any one of claims 1 to 11.

Technical Field

The invention relates to the technical field of sound generating devices, in particular to a vibrating plate and a sound generating device.

Background

The diaphragm is a main component of a sound generating device (such as a speaker), and the selection of the material of the diaphragm affects the power of the sound generating device. In the related art, the vibrating plate is usually made of paper, the paper vibrating plate is also called a cone, and the cone has certain rigidity, proper internal damping and lower density, but because the paper material is easy to change at different temperatures, especially at high temperature, the cone is easy to dehydrate and become brittle, so when the sound generating device has higher power, the voice coil generates heat seriously, and the cone is difficult to bear the high temperature, so that the sound generating device generates sound abnormally.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The invention mainly aims to provide a vibrating plate and a sound generating device, aiming at ensuring that the sound generating device has better sound generating effect under larger using power.

In order to achieve the above purpose, the vibrating plate provided by the invention comprises at least one composite fiber layer, wherein the composite fiber in the composite fiber layer comprises polyetherimide fiber and carbon fiber.

Optionally, the polyetherimide fiber has a modulus in the range of 1GPa to 9 GPa.

Optionally, the polyetherimide fiber has a glass transition temperature in a range of 200 ℃ to 260 ℃.

Optionally, the carbon fibers are present in an amount of 5% to 90% of the polyetherimide fibers.

Optionally, the carbon fibers are staple fibers having a length in the range of 0.5mm to 20 mm; and/or the modulus of the carbon fiber ranges from 100GPa to 500 GPa.

Optionally, the composite fiber layer has a density in the range of 0.3g/cm³To 1.2g/cm³(ii) a And/or the thickness of the composite fiber layer ranges from 50 μm to 1500 μm.

Alternatively, the elastic modulus of the vibration plate ranges from 2GPa to 40 GPa.

Optionally, the composite fiber further comprises a binder fiber selected from at least one of polyvinyl alcohol fiber, polyethylene fiber, polyamide-nitrile fiber, polyvinyl chloride fiber.

Optionally, the binder fiber is present in an amount of 1% to 20% by mass of the polyetherimide fiber.

Optionally, the vibrating plate further includes at least one of a rubber film layer, a polymer film layer, and a thermoplastic elastomer layer, and adjacent two layers are bonded or thermally pressed.

Optionally, when the vibrating plate includes a glue film layer, the material of the glue film layer is at least one selected from acrylic glue, epoxy glue and silica gel; and/or when the vibrating plate comprises a rubber film layer, the material of the rubber film layer is selected from at least one of nitrile rubber, hydrogenated nitrile rubber, ethylene propylene diene monomer, butyl rubber, ethylene-acrylic acid rubber, acrylate rubber, natural rubber, styrene butadiene rubber and styrene butadiene rubber; and/or, when the diaphragm comprises a polymer film layer, the material of the polymer film layer is selected from at least one of polypropylene, polyethylene terephthalate, polyether ether ketone, polyarylate, polyamide, liquid crystal polymer, polyetherimide and polyimide; and/or, when the vibration plate comprises a thermoplastic elastomer layer, the material of the thermoplastic elastomer layer is at least one selected from thermoplastic polyurethane elastomer and thermoplastic polyester elastomer.

The invention further provides a sound production device which comprises a vibration plate, wherein the vibration plate comprises at least one composite fiber layer, and the composite fibers in the composite fiber layer comprise polyetherimide fibers and carbon fibers.

According to the technical scheme, the vibrating plate comprises at least one composite fiber layer, compared with a paper vibrating plate, the vibrating plate is high in modulus and proper in damping, and has a wide frequency response range, accurate sound production and low distortion when being applied to a sound production device. Furthermore, the composite fiber in the composite fiber layer is made of a composite fiber material of polyetherimide fiber and carbon paper fiber, and after the polyetherimide fiber and the carbon paper fiber are compounded, the carbon fiber can be inserted into the polyetherimide fiber to form a reinforced three-dimensional network structure, so that the composite fiber layer has high modulus, loss factor and high temperature resistance. So, can further promote the modulus of vibration board, make the vibration board have excellent high temperature resistance simultaneously, can bear higher power to guarantee that sound generating mechanism has better vocal effect under great use power.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic partial structure diagram of a sound generating device according to an embodiment of the present invention;

FIG. 2 is a graph of the effect of carbon fiber content on modulus in a composite fiber;

FIG. 3 is a graph of the effect of carbon fiber length on its modulus;

FIG. 4 is a graph of the effect of composite fiber layer density on the acoustic performance of a vibrating plate;

fig. 5 is a graph showing the frequency response of the diaphragm and cone of the present invention after they are applied to a speaker.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				100	Sound producing device	20	Ball top
10	Folded ring part	30	Voice coil

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, the technical solutions in the embodiments of the present invention may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination of technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

The invention provides a vibrating plate, which is applied to a sound generating device 100, wherein the sound generating device 100 can be a loudspeaker.

Referring to fig. 1, the sound generating device 100 includes a dome portion 20, a folded ring portion 10 and a voice coil 30, the folded ring portion 10 is disposed at an edge position of the sound generating device 100, the dome portion 20 is located at a central position of the sound generating device 100, the dome portion 20 is connected to one side of the folded ring portion 10, the voice coil 30 is connected to the other side of the folded ring portion 10, the dome portion 20 is a vibration plate of the present invention, and the vibration plate vibrates by sensing external sound changes. When the sound generating device 100 is assembled, the edge portion 10 is attached to a housing of the sound generating device 100, the housing is provided with a sound hole corresponding to the vibrating plate, and the sound generating device 100 generates a corresponding sound by the vibration of the vibrating plate.

In an embodiment of the present invention, the vibrating plate includes at least one composite fiber layer, and the composite fibers in the composite fiber layer include polyetherimide fibers and carbon fibers.

The vibrating plate may be a single-layer structure, that is, a single-layer composite fiber layer, or may be a multi-layer composite structure, for example, two composite fiber layers, three composite fiber layers, or more composite fiber layers, the multi-layer composite fiber layers are stacked, and adjacent two composite fiber layers are bonded by gluing or hot-pressing. The composite fiber in the composite fiber layer is mainly the composite of polyetherimide fiber and carbon fiber, the polyetherimide fiber is a high-modulus fiber, the modulus of the fiber is higher than that of paper, and the polyetherimide fiber has excellent high temperature resistance and can be used for a long time at 180 ℃. The carbon fiber has higher strength, and after the carbon fiber and the polyetherimide fiber are compounded, the carbon fiber can be inserted into the polyetherimide fiber to form a reinforced three-dimensional network structure, so that the modulus of the composite fiber material can be effectively improved, and the loss factor of the composite fiber material is also improved. When the composite fiber layer made of the composite fiber material is used as vibration, the composite fiber layer not only has a wider frequency response range, is accurate in sound production and lower in distortion, but also can bear higher power due to excellent high-temperature resistance, and ensures that a sound production device has a better sound production effect under larger using power.

Therefore, it can be understood that, according to the technical scheme of the invention, the vibrating plate comprises at least one composite fiber layer, compared with a paper vibrating plate, the vibrating plate has the advantages of higher modulus, proper damping, wider frequency response range, accurate sound production and lower distortion when being applied to a sound production device. Furthermore, the composite fiber in the composite fiber layer is made of a composite fiber material of polyetherimide fiber and carbon paper fiber, and after the polyetherimide fiber and the carbon paper fiber are compounded, the carbon fiber can be inserted into the polyetherimide fiber to form a reinforced three-dimensional network structure, so that the composite fiber layer has high modulus, loss factor and high temperature resistance. So, can further promote the modulus of vibration board, make the vibration board have excellent high temperature resistance simultaneously, can bear higher power to guarantee that sound generating mechanism has better vocal effect under great use power.

Alternatively, the polyetherimide fiber has a modulus in the range of 1GPa to 9 GPa.

The polyetherimide fiber determines the basic modulus of the composite fiber material, and the higher the modulus of the polyetherimide fiber in the composite fiber material is, the easier the modulus of the composite fiber layer is to be enhanced, so that the modulus of the vibrating plate is effectively improved. Typically, the polyetherimide fiber has a modulus of 1GPa, 3GPa, 5GPa, 7GPa, or 9 GPa.

Alternatively, the polyetherimide fiber has a glass transition temperature in the range of 200 ℃ to 260 ℃.

The polyetherimide fiber is composed of ether and imide rings arranged regularly and alternately, and exhibits excellent high temperature resistance, and the glass transition temperature is 190-270 ℃ according to the type of the polyetherimide fiber, and the higher the glass transition temperature, the better the high temperature resistance, but if the glass transition temperature is too high, the toughness of the polyetherimide fiber is deteriorated, so an appropriate glass transition temperature should be selected, and generally, the glass transition temperature of the polyetherimide fiber may be 200 ℃, 220 ℃, 240 ℃ or 260 ℃.

Optionally, the carbon fiber is present in an amount of 5% to 90% by mass of the polyetherimide fiber.

The carbon fiber content affects the modulus of the composite fiber material, please refer to fig. 2, fig. 2 is a graph illustrating the effect of the carbon fiber content on the modulus of the composite fiber, and it can be seen from the graph that the higher the carbon fiber content is, the higher the modulus of the composite fiber material is, and the higher the modulus of the vibrating plate made of the composite fiber layer is, however, when the carbon fiber content is too high, the composite fiber layer is brittle and not easy to process, so the amount of the carbon fiber should be selected appropriately. Generally, the carbon fiber is present in an amount of 5 parts, 15 parts, 25 parts, 40 parts, 60 parts, 75 parts, or 90 parts, based on 100 parts by mass of the polyetherimide fiber in the composite fiber material.

Optionally, the carbon fibers are staple fibers having a length in the range of 0.5mm to 20 mm.

The carbon fibers are short fibers, namely chopped fibers. The length of the carbon fibers in the composite fibers also has a significant effect on the modulus-enhancing effect of the composite fibers. Referring to fig. 3, fig. 3 is a graph illustrating the effect of the length of carbon fiber on its modulus. It can be understood that, in the case of a certain carbon fiber content, the longer the carbon fiber length is, the easier the three-dimensional net-shaped reinforcing structure is formed in the composite fiber material, and the better reinforcing effect is achieved. When the length of the carbon fiber is too short, the modulus reinforcing effect is not obvious; however, when the length of the carbon fiber is increased to a certain extent, the modulus-enhancing effect thereof is no longer enhanced as the length of the carbon fiber is increased. So optionally the length of the carbon fibres may be 0.5mm, 1.5mm, 3.5mm, 5mm, 8mm, 10mm, 12mm, 15mm, 18mm or 20 mm.

Optionally, the modulus of the carbon fiber ranges from 100GPa to 500 GPa. The high modulus carbon fiber can effectively enhance the modulus of the composite fiber, but in view of its processability, the carbon fiber can generally have a modulus of 100GPa, 150GPa, 200GPa, 250GPa, 350GPa, 450GPa, or 500 GPa.

Because the vibrating plate comprises at least one composite fiber layer, the composite fibers in the composite fiber layer are polyetherimide fibers as base materials, after the composite fiber layer is reinforced by high-modulus carbon fibers, the modulus of the composite fiber layer is greatly enhanced, the modulus of the vibrating plate consisting of the composite fiber layer far exceeds that of a cone, but the modulus is limited by the processing performance, the enhancing effect cannot be infinitely improved, optionally, the elastic modulus of the vibrating plate consisting of the composite fiber layer ranges from 2GPa to 40GPa, for example, the elastic modulus of the vibrating plate can be 2GPa, 10GPa, 15GPa, 20GPa, 30GPa or 40 GPa.

Optionally, the composite fiber layer has a density in the range of 0.3g/cm³To 1.2g/cm³。

Because the vibrating plate is the composite fiber layer and a certain gap exists between fibers in the composite fiber layer, the overall density of the composite fiber layer can be adjusted by adjusting the compactness of the composite fiber material, generally, the lower the material density is, the lower the strength is, and when the material density is too high, the damping of the material is poor, so that the density of the composite fiber layer is selected properly, generally, the density of the composite fiber layer can be 0.3g/cm³、0.5g/cm³、0.8g/cm³、1.0g/cm³Or 1.2g/cm³。

It can be understood that in order to adjust the acoustic performance of the vibrating plate of the present invention to have a better sound-emitting effect, the modulus and the internal damping of the composite fiber layer can be adjusted by adjusting the degree of compaction of the composite fiber material. Referring to fig. 4, fig. 4 is a graph showing the effect of the density of the composite fiber layer on the acoustic performance of the vibrating plate, and it can be seen from the graph that when the density of the composite fiber layer is lower, the composite fiber material is looser, the modulus of the composite fiber material is lower, but the material has higher damping because the gaps between the materials are larger, and the fibers are easier to move. When the density of the composite fiber layer is increased, bonding between fibers in the composite fiberMore compact, with limited fiber movement, the modulus of the material will increase significantly, but the damping of the material will decrease when the composite fiber layer density exceeds 1.2g/cm³When the fibers are substantially completely bonded together, the modulus is higher, but the damping is lower, and the resulting diaphragm will have higher distortion. Therefore, a composite fiber layer with a suitable density is selected to be used for manufacturing the vibrating plate.

Optionally, the composite fibre layer has a thickness in the range of 50 μm to 1500 μm.

The vibrating plate of the present invention may be a single-layer composite fiber layer or a multi-layer composite fiber layer, and the thickness of the single-layer composite fiber layer is in the range of 50 μm to 1500 μm, preferably in the range of 50 μm to 1000 μm, considering the manufacturing thickness and the processing characteristics of the vibrating plate, for example, the thickness of the composite fiber layer may be 50 μm, 100 μm, 300 μm, 500 μm, 700 μm, 850 μm or 1000 μm.

Further, the composite fiber also comprises a binding fiber, and the binding fiber is selected from at least one of polyvinyl alcohol fiber, polyethylene fiber, polyetherimide nitrile fiber and polyvinyl chloride fiber.

In the composite fiber, the polyetherimide fiber and the carbon fiber are fused and combined together through the fiber, the better the bonding strength of the carbon fiber and the polyetherimide fiber is, and the better the reinforcing effect of the carbon fiber is. In order to enhance the bonding force between the carbon fibers and the polyetherimide fibers, bonding fibers are added to increase the bonding between the fibers and enhance the bonding effect of the fibers. When binder fibers are selected, one or more of polyvinyl alcohol fibers, polyethylene fibers, polyetherimide nitrile fibers and polyvinyl chloride fibers can be selected.

Since the binder fiber mainly plays a role in enhancing the inter-fiber adhesion, if the content is too low, the adhesion effect is affected, and if the content is too high, the overall modulus of the composite fiber material is affected, the amount of the binder fiber is suitably selected, and optionally, the content of the binder fiber is 1 to 20% by mass of the polyetherimide fiber. That is, the binder fiber may be present in an amount of 1 part, 3 parts, 5 parts, 8 parts, 12 parts, 15 parts, 17 parts, or 20 parts, based on 100 parts by mass of the polyetherimide fiber.

Referring to table 1, table 1 is a table comparing physical properties of cones, polyetherimides, and polyetherimide-carbon fiber composite materials. As can be seen from the table, the modulus and specific modulus of elasticity of the composite fiber material are both higher than those of the cone and the polyetherimide, which indicates that the composite fiber material has higher modulus, stronger abrasion resistance and elasticity.

TABLE 1 comparison of physical Properties of cone, polyetherimide and polyetherimide-carbon fiber composite fiber Material

Kind of material	Density/g/cm	modulus/Gpa	Specific elastic modulus E/rho
				Paper basin	0.5	3	6
Polyetherimide fiber	1.2	5.2	4.3
				Polyetherimide fiber-carbon fiber composite material	0.6	15	25

Furthermore, the vibrating plate further comprises at least one of a rubber film layer, a polymer film layer and a thermoplastic elastomer layer, and the two adjacent layers are connected by gluing or hot pressing.

When the vibrating plate is of a multilayer structure, the vibrating plate can comprise one or more of a rubber film layer, a polymer film layer and a thermoplastic elastomer layer besides a composite fiber layer, and two adjacent layers can be combined by gluing or hot-pressing. Wherein the damping of vibration board can be increased to glue film layer and rubber film layer, slows down the vibration of cutting apart of vibration board, and then improves sound generating mechanism's distortion, promotes its sound production effect. The polymer film layer and the plastic layer can improve the resilience of the vibrating plate, increase the toughness of the vibrating plate, reduce the cracking possibility of the vibrating plate and improve the reliability of the vibrating plate.

Optionally, when the vibrating plate includes the glue film layer, the material of the glue film layer is at least one selected from acrylic glue, epoxy glue and silica gel.

Optionally, when the vibrating plate includes a rubber film layer, the material of the rubber film layer is at least one selected from nitrile rubber, hydrogenated nitrile rubber, ethylene propylene diene monomer, butyl rubber, ethylene-acrylic acid rubber, acrylate rubber, natural rubber, styrene butadiene rubber, and styrene butadiene rubber.

Alternatively, when the diaphragm includes a polymer film layer, the material of the polymer film layer is at least one selected from the group consisting of polypropylene, polyethylene terephthalate, polyetheretherketone, polyarylate, polyetherimide, liquid crystal polymer, polyetherimide, and polyimide.

Alternatively, when the vibration plate includes the thermoplastic elastomer layer, the material of the thermoplastic elastomer layer is at least one selected from the group consisting of a thermoplastic polyurethane elastomer and a thermoplastic polyester elastomer.

It should be noted that the vibrating plate of the present invention can be prepared by the following steps:

firstly, dispersing polyetherimide fibers and carbon fibers into a solvent, uniformly mixing, and removing the solvent to obtain the composite fiber material. Wherein the mass ratio of the polyetherimide fiber to the carbon fiber is in the range of 100:5 to 100: 90. The solvent can be water or organic solvent, and the organic solvent can be one or more of methanol, ethanol, isopropanol, acetone, butanone, ethyl acetate, butyl acetate, n-hexane, cyclohexane, petroleum ether and toluene.

Secondly, the composite fiber material is placed in a mold and compressed according to a preset compression ratio, and then the composite fiber layer with preset density can be prepared.

In order to enhance the adhesion between the carbon fibers and the polyetherimide fibers in the composite fibers, a binder fiber is further added to the solvent, and the content of the binder fiber is 1 to 20 parts by mass based on 100 parts by mass of the polyetherimide fiber.

Furthermore, in order to enhance the dispersion effect of the carbon fibers in the solvent, a surfactant can be added into the solvent, and the adding amount of the surfactant is 0.2-5 parts by mass of the solvent. Here, the surfactant may be one or more of Disodium Lauryl Sulfosuccinate (DLS), disodium fatty alcohol-polyoxyethylene ether (3) sulfosuccinate Monoester (MES), disodium coconut monoethanolamide sulfosuccinate monoester (DMSS), monolauryl phosphate (MAP), potassium monolauryl phosphate (MAPK), potassium laureth phosphate (MAEPK), ammonium fatty alcohol-polyoxyethylene ether (EO ═ 3) sulfate (AESA), Coconut Monoethanolamide (CMEA), cocamidopropyl betaine (CAB-35), lauramidopropyl betaine (LAB-35), Cocamidopropyl Hydroxysultaine (CHSB), lauramidopropyl hydroxysultaine (LHSB-35), and fatty acid potassium Soap (SFP).

Further, in order to enhance the adhesion of the carbon fiber to the polyetherimide fiber, the carbon fiber may be a carbon fiber treated with a silicon coupling agent, where the silane coupling agent may be at least one of KH-540, KH-550, KH-560, KH-570, KH-590, KH-792, Si-602, Si-563, A-151.

It should be noted that the addition of the silane coupling agent can also improve the dispersibility of the carbon fibers in water, and it can be understood that when the silane coupling agent is selected to treat the carbon fibers, the surfactant can not be added, and the dispersing effect of the carbon fibers can also be enhanced, so that the material cost for preparing the composite fibers can be saved to a certain extent.

The invention also provides a sound generating device, which comprises the vibrating plate as described above, and the specific structure of the vibrating plate refers to the foregoing embodiment. Since the sound generating device adopts all technical solutions of all the foregoing embodiments, at least all the beneficial effects brought by the technical solutions of the foregoing embodiments are achieved, and no further description is given here.

The diaphragm and the speaker of the present invention will be described in detail below with reference to specific examples.

Example 1

The vibration plate of the present example was prepared by the following steps:

1. 100 parts by mass of 10 μm diameter polyetherimide fiber is cut into short fibers of 20mm to 40mm in length, dispersed in 400 parts by mass of ethanol solvent, and stirred to disperse uniformly.

2. 40 parts of carbon fibers with the diameter of 7 mu m are weighed, cut into short fibers with the average length of 20mm, added into the ethanol solvent, and stirred continuously to ensure that the two fibers are uniformly dispersed in the ethanol solvent.

3. And removing the two fibers from the ethanol solvent, drying to remove the ethanol solvent, and obtaining the composite fiber material in which the carbon fibers and the polyetherimide fibers are uniformly compounded, wherein the composite fiber material is in a three-dimensional net structure.

4. And (3) placing the composite fiber material in a mold, and compressing according to a preset compression ratio to prepare a composite fiber layer with preset density, namely a vibrating plate of the single-layer composite fiber layer.

The prepared vibration plate and paper cone were applied to a speaker, and the frequency response curve thereof was measured, as shown in fig. 5. As can be seen from the figure, the speaker to which the diaphragm of the present embodiment is applied has a higher high-frequency cutoff frequency and a wider effective frequency response curve range.

Example 2

The carbon fiber of example 1 was treated with a coupling agent, and the other steps were the same as those of example 1.

The specific steps of treating the carbon fiber by the coupling agent are as follows:

firstly, 10 parts of coupling agent is added into a blending solvent of 100 parts of water and 900 parts of ethanol, and the mixture is fully stirred to obtain the pretreating agent.

Then, 40 parts of 7 μm diameter carbon fibers were cut into short fibers having an average length of 20mm, and the short fibers were added to the above pretreating agent, sufficiently stirred, and then allowed to stand for 4 hours.

And then filtering and taking out the treated carbon fiber, and drying to obtain the carbon fiber after surface treatment.

Here, the coupling agent may be one or more selected from KH-540, KH-550, KH-560, KH-570, KH-590, KH-792, Si-602, Si-563 and A-151. And the amount of the coupling agent is in the range of 0.1 to 2 parts by mass based on 100 parts by mass of the blending solvent.

Experiments show that the loudspeaker applied with the vibrating plate of the embodiment has higher high-frequency cut-off frequency and wider effective frequency response curve range.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.