Diaphragm of sound-generating device and preparation method thereof, and sound-generating device

Abstract

The present application discloses a diaphragm of a sound-generating device, a preparation method thereof, and a sound-generating device. The diaphragm includes a damping layer and a woven fabric layer. At least one side of the woven fabric layer is coated with a damping layer. The damping layer includes a base rubber and inorganic hollow microspheres. The particle size of the inorganic hollow microspheres is 10 μm to 100 μm, and the distribution density of the inorganic hollow microspheres in the damping layer is 0.15 g / cm 3 ~0.9g / cm 3 The compressive strength of the inorganic hollow microspheres is ≥10Mpa. The diaphragm of the present application, by compounding a damping layer containing inorganic hollow microspheres with a woven fabric layer, not only provides the diaphragm with suitable rigidity, but also effectively reduces the mass of the diaphragm, prolongs the service life of the diaphragm, and improves the sensitivity and damping performance of the diaphragm. This allows a sound-generating device using the diaphragm material of the present application to have lower distortion at low frequencies, thereby improving the acoustic performance of the sound-generating device.

Description

Technical Field

[0001] The present application relates to the field of electroacoustic technology, and more specifically, to a diaphragm of a sound-generating device, a method for preparing the same, and a sound-generating device using the diaphragm. Background Art

[0002] Currently, the polyurethane foam used in diaphragms on the market has poor durability. During speaker operation, the diaphragms are prone to loosening, deformation, rupture, and even cell collapse. Rubber diaphragms have good damping, compliance, and fatigue resistance. However, rubber diaphragms are heavy, which increases the mass of the vibration system and reduces the speaker's sound sensitivity. Rubber diaphragms are also expensive, increasing production costs. In addition, cloth-impregnated rubber diaphragms have also been introduced on the market. Although cloth-impregnated rubber diaphragms are of lower mass than rubber diaphragms, their damping is far less than that of rubber diaphragms, which seriously affects the acoustic stability of the speaker.

[0003] Therefore, a new technical solution is needed to solve the above problems. Summary of the Invention

[0004] One object of the present application is to provide a diaphragm for a sound-generating device.

[0005] Another object of the present application is to provide a method for preparing the above-mentioned diaphragm.

[0006] Another object of the present application is to provide a sound-generating device composed of the above-mentioned diaphragm.

[0007] According to the diaphragm of the sound-generating device of the first embodiment of the present application, the diaphragm includes a damping layer and a woven fabric layer, at least one side of the woven fabric layer is coated with the damping layer, the damping layer includes a base rubber and inorganic hollow microspheres, wherein the particle size of the inorganic hollow microspheres is 10 μm to 100 μm, and the distribution density of the inorganic hollow microspheres in the damping layer is 0.15 g / cm 3 ~0.9g / cm 3 , the compressive strength of the inorganic hollow microspheres is ≥10Mpa.

[0008] According to some embodiments of the present application, the diaphragm for the sound-generating device according to claim 1 has a density of 0.5 g / cm 3 ~1.1g / cm 3 .

[0009] According to the second aspect of the present application, a method for preparing a diaphragm of a sound-emitting device comprises: adding inorganic hollow microbeads to a base rubber latex to obtain a modified rubber latex, applying the modified rubber latex to at least one side of a woven fabric layer, and after drying, forming a damping layer on the woven fabric layer to obtain a composite membrane material; hot-pressing the composite membrane material to obtain a composite membrane; and cutting the composite membrane to obtain the diaphragm.

[0010] According to some embodiments of the present application, the content of the inorganic hollow microspheres accounts for 5 wt % to 50 wt % of the total amount of the base rubber latex.

[0011] According to some embodiments of the present application, the surface density of the woven fabric layer is 10 g / m 2 ~150g / m 2 The surface density of the composite film is 30g / m 2 ~300g / m 2 .

[0012] According to some embodiments of the present application, the composite film has a thickness of 0.05 mm to 0.35 mm.

[0013] According to some embodiments of the present application, the modulus of the composite film is 300 MPa to 1500 MPa.

[0014] According to some embodiments of the present application, the damping of the composite film is greater than 0.08.

[0015] According to some embodiments of the present application, the material of the woven fabric layer is plain woven fabric, and the plain woven fabric is any one of plain woven cotton fabric, plain woven PET fabric and plain woven natural silk fabric.

[0016] According to some embodiments of the present application, the plain woven fabric includes a plurality of wire bundles, and there is a gap between adjacent wire bundles, and the size of the gap is 10 μm to 300 μm.

[0017] According to some embodiments of the present application, the gap is filled with the modified rubber latex.

[0018] According to some embodiments of the present application, each of the wiring harnesses includes a plurality of wires, the number of the wires is 10 to 40, and the diameter of the wires is 5 μm to 25 μm.

[0019] According to some embodiments of the present application, before applying the modified rubber latex to the woven fabric layer, the preparation method further includes: immersing the plain woven fabric in a thermosetting resin solution and performing thermosetting resin treatment to obtain the woven fabric layer, wherein the thermosetting resin includes a thermosetting phenolic resin and a thermosetting epoxy resin.

[0020] According to some embodiments of the present application, the coating method is dipping, blade coating, roller coating or spraying.

[0021] According to some embodiments of the present application, the base rubber latex is one or more of natural rubber latex, styrene-butadiene rubber latex, butadiene rubber latex, isoprene rubber latex, chloroprene rubber latex, butyl rubber latex, nitrile rubber latex, chlorinated nitrile rubber latex, ethylene-propylene rubber latex, silicone rubber latex, fluororubber latex, polyurethane rubber latex, acrylate rubber latex, chlorosulfonated polyethylene rubber latex, epichlorohydrin rubber latex, polysulfide rubber latex and ethylene-vinyl acetate rubber latex.

[0022] According to the third aspect of the embodiment of the present application, the sound-producing device includes a vibration system and a magnetic circuit system coordinated with the vibration system, the vibration system includes a diaphragm and a voice coil coupled to one side of the diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the diaphragm to produce sound, and the diaphragm is the diaphragm according to the above-mentioned embodiment of the present application.

[0023] According to the fourth aspect of the present application, the sound-producing device includes a shell and a magnetic circuit system and a vibration system arranged in the shell. The vibration system includes a voice coil, a first diaphragm and a second diaphragm. The top of the voice coil is connected to the first diaphragm. The magnetic circuit system drives the voice coil to vibrate to drive the first diaphragm to produce sound. The two ends of the second diaphragm are respectively connected to the shell and the bottom of the voice coil. The second diaphragm is the diaphragm according to the above-mentioned embodiment of the present application.

[0024] According to the diaphragm of the sound-emitting device of the embodiment of the present application, by compounding a damping layer to which inorganic hollow microbeads are added with a woven fabric layer, the diaphragm can have suitable rigidity while effectively reducing the mass of the diaphragm, extending the service life of the diaphragm, and improving the sensitivity and damping performance of the diaphragm, so that the sound-emitting device using the diaphragm material of the present application can have lower distortion in the low-frequency state.

[0025] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0027] Figure 1 The following are test curves (SPL curves) of the loudness of the speaker with the diaphragm of the sound-generating device according to the embodiment of the present application and the speaker with a conventional rubber diaphragm at different frequencies;

[0028] Figure 2The harmonic distortion test curves (THD curves) of the speaker with a diaphragm and the speaker with a cloth-impregnated rubber diaphragm of the sound-generating device according to the embodiment of the present application are shown;

[0029] Figure 3 A schematic structural diagram of a plain woven fabric according to a method for preparing a diaphragm of a sound-generating device according to an embodiment of the present application;

[0030] Figure 4 A cross-sectional view of a composite film coated with a damping layer on one side according to a method for preparing a diaphragm of a sound-generating device according to an embodiment of the present application;

[0031] Figure 5 A cross-sectional view of a composite film coated with damping layers on both sides according to a method for preparing a diaphragm of a sound-generating device according to an embodiment of the present application;

[0032] Figure 6 Schematic diagram of the overall structure of the sound-generating device according to an embodiment of the present application;

[0033] Figure 7 is a schematic diagram of a partial structure of a sound-generating device according to an embodiment of the present application;

[0034] Figure 8 is a cross-sectional view of a sound-generating device according to an embodiment of the present application;

[0035] Figure 9 1 is an exploded view of a sound-generating device according to an embodiment of the present application.

[0036] Reference numerals

[0037] Sound-generating device 100;

[0038] Housing 10; voice coil 11; first diaphragm 12; second diaphragm 13; magnetic circuit system 14;

[0039] Diaphragm 15 ; surround 151 ; dome 152 . DETAILED DESCRIPTION

[0040] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application.

[0041] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0042] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0043] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0044] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0045] The diaphragm of the sound-emitting device according to the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0046] According to the diaphragm of the sound-generating device of the embodiment of the present application, the diaphragm includes a damping layer and a woven fabric layer. At least one side of the woven fabric layer is coated with a damping layer, and the damping layer includes a base rubber and inorganic hollow microspheres. The particle size of the inorganic hollow microspheres is 10 μm to 100 μm, and the distribution density of the inorganic hollow microspheres in the damping layer is 0.15 g / cm 3 ~0.9g / cm 3 , the compressive strength of inorganic hollow microspheres is ≥10Mpa.

[0047] The diaphragm of the sound-emitting device according to the embodiment of the present application may include only a damping layer and a fabric layer, or may be a composite structure including multiple layers. When the diaphragm is a multi-layer composite structure, the diaphragm includes a damping layer and a fabric layer, and the diaphragm may be composed of a composite of the damping layer and the fabric layer and a film layer of other materials.

[0048] The damping layer is made by adding inorganic hollow microspheres to a base rubber. The damping layer is applied to the fabric layer and can be applied to either or both sides of the fabric layer. In other words, applying the damping layer to the fabric layer forms a single, integrated composite layer.

[0049] Inorganic hollow microspheres are hollow, thin-walled, hard, and lightweight spheres with a high strength-to-density ratio. Filling the damping layer of the diaphragm of the sound-generating device in this application with inorganic hollow microspheres effectively reduces the density of the base rubber and the weight of the damping layer, thereby reducing the overall weight of the diaphragm, lowering the vibration mass of the vibration system, and improving the sensitivity of the sound-generating device.

[0050] Furthermore, when sound waves enter the material, a large number of longitudinal waves undergo waveform transformation at the interface, increasing sound wave loss. However, the internal cavity size of the inorganic hollow microspheres is much larger than the interface size between the inorganic hollow microspheres and the rubber. The cavity resonance generated within the inorganic hollow microspheres can absorb sound waves with longer wavelengths, reducing sound wave loss. Therefore, the diaphragm of the present application has higher damping, and sound-generating devices using the diaphragm material of the present application can achieve lower distortion at low frequencies.

[0051] Inorganic hollow microspheres can be hollow glass microspheres, hollow ceramic microspheres, etc. Among them, hollow glass microspheres can be composed of inorganic materials such as silica, alumina, zirconium oxide, magnesium oxide, sodium silicate, etc. and internally enclosed gas. The main component of the hollow glass microsphere shell is borosilicate, which has the characteristics of high rigidity, good chemical stability and high melting point. After filling it into rubber, it can effectively prevent rubber aging caused by light and heat, thereby improving the temperature resistance of the rubber material. In addition, hollow microspheres are very excellent thermal insulation materials that can effectively block external heat and effectively slow down the damage of external heat to the internal network structure of the rubber. Thereby increasing the service life of the diaphragm.

[0052] In other words, inorganic hollow microspheres have a high compressive strength, exceeding 10 MPa. This not only prevents them from being crushed during the mixing process, but also effectively increases the tensile strength of the fabric and damping layers when added to the base rubber, ensuring the diaphragm has appropriate stiffness and damping. The diaphragm's high mechanical strength prevents it from overstretching due to excessive driving forces in extreme environments, further ensuring its effectiveness.

[0053] Furthermore, the particle size of the inorganic hollow microspheres can be selected within the range of 10 μm to 100 μm, preferably 15 μm to 70 μm. For example, the particle size of the inorganic hollow microspheres can be 10 μm, 12 μm, 15 μm, 20 μm, 30 μm, 40 μm, 50 μm, 70 μm, or 100 μm. Inorganic hollow microspheres of different particle sizes can be selected according to the thickness of the diaphragm to ensure that the inorganic hollow microspheres are evenly dispersed in the substrate.

[0054] Among them, inorganic hollow microbeads with smaller sizes are easy to agglomerate and difficult to disperse in the base rubber latex. Inorganic hollow microbeads with larger sizes have lower strength and are easy to break. Inorganic hollow microbeads that are too large or too small will form defects in the rubber, reducing the overall tensile strength and elongation at break of the material. The size of the inorganic hollow microbeads used in this application can make the inorganic hollow microbeads tightly bonded to the rubber interface, increase the strength of the diaphragm, bear a certain load, and play a reinforcing role. Since the diaphragm is the weakest component in the sound-generating device and is easily damaged during repeated vibrations, the service life of the sound-generating device can be extended by ensuring the normal use of the diaphragm for a long time. When the diaphragm is applied to a loudspeaker, the diaphragm is not prone to relaxation, deformation, or rupture during the operation of the loudspeaker.

[0055] In addition, as the size of the inorganic hollow microspheres decreases, the distribution density of the inorganic hollow microspheres in the damping layer will increase. By selecting the appropriate size and addition amount of the inorganic hollow microspheres, the distribution density of the inorganic hollow microspheres in the damping layer can be controlled at 0.15g / cm3 ~0.9g / cm 3 For example, the distribution density of inorganic hollow microspheres can be 0.15 g / cm 3 , 0.2g / cm 3 , 0.35g / cm 3 , 0.5g / cm 3 , 0.6g / cm 3 , 0.7g / cm 3 , 0.8g / cm 3 or 0.9g / cm 3 To ensure that the inorganic hollow microspheres can effectively reduce the density of the diaphragm, the distribution density of the inorganic hollow microspheres is preferably 0.35 g / cm 3 ~0.8g / cm 3 .

[0056] Because the damping layer is coated on the fabric layer, and because the damping layer has excellent mechanical properties, the composite layer formed by the damping layer and the fabric layer also has excellent mechanical properties, and can simultaneously combine the flexibility of the damping layer with the rigidity of the fabric base material. The diaphragm of the present application has the advantages of high damping and light weight, overcoming the shortcomings of diaphragms in the prior art.

[0057] According to some embodiments of the present application, the density of the diaphragm is 0.5 g / cm 3 ~1.1g / cm 3 It is understood that by adding inorganic hollow microspheres to the base rubber to form a damping layer and coating the damping layer on at least one side of the fabric layer, the diaphragm can be reduced in weight by 30% to 50%, greatly improving the sound sensitivity of the diaphragm. Optionally, the density of the diaphragm can be 0.5g / cm 3 , 0.6g / cm 3 , 0.7g / cm 3 , 0.8g / cm 3 , 0.9g / cm 3 , 1g / cm 3 or 1.1 g / cm 3 .

[0058] Thus, the diaphragm of the sound-generating device according to the embodiment of the present application, by compounding a damping layer containing inorganic hollow microspheres with a woven fabric layer, not only provides the diaphragm with suitable rigidity, but also effectively reduces the mass of the diaphragm, prolongs the service life of the diaphragm, and improves the sensitivity and damping performance of the diaphragm. This enables the sound-generating device using the diaphragm material of the present application to have lower distortion at low frequencies. Therefore, the sound-generating device using the diaphragm of the present application has the advantages of high acoustic stability and low cost.

[0059] According to a second embodiment of the present application, a method for preparing a diaphragm of a sound-generating device comprises: adding inorganic hollow microbeads to a base rubber latex to obtain a modified rubber latex; applying the modified rubber latex to at least one side of a woven fabric layer; and, after drying, forming a damping layer on the woven fabric layer to obtain a composite membrane material. The composite membrane material is then hot-pressed to obtain a composite membrane. The composite membrane is then cut to obtain a diaphragm material.

[0060] Specifically, first, inorganic hollow microspheres can be added to the base rubber latex and mixed to obtain modified rubber latex. Figure 4 and Figure 5 As shown, the modified rubber latex can then be coated on either or both sides of the fabric layer. After the modified rubber latex dries on the fabric layer, a damping layer is formed to obtain a composite membrane material. The composite membrane material can then be placed on a molding machine for hot pressing. The molding temperature can be between 200°C and 260°C (including the end points), and the holding time is between 6s and 15s (including the end points). After the holding is completed, the mold is opened to obtain a composite membrane. Finally, after the composite membrane cools down, it is punched or laser cut according to the diaphragm design requirements to obtain the diaphragm material. The preparation process is simple and can reduce the production cost of the diaphragm material.

[0061] Therefore, according to the preparation method of the diaphragm of the sound-emitting device of the embodiment of the present application, a diaphragm material with inorganic hollow microbeads can be obtained by coating rubber latex added with inorganic hollow microbeads onto the woven fabric layer. Not only is the process simple, but the density and mass of the diaphragm are reduced, so that the diaphragm has higher damping. The sound-emitting device using the diaphragm of the present application has better acoustic performance.

[0062] In some specific embodiments of the present application, the content of the inorganic hollow microspheres accounts for 5 wt % to 50 wt % of the total amount of the base rubber latex.

[0063] In other words, a damping layer can be prepared by adding 5wt% to 50wt% of inorganic hollow microspheres to a base rubber latex. As the amount of inorganic hollow microspheres added increases, the density of the damping layer decreases. By controlling the density of the inorganic hollow microspheres added, a diaphragm material with desired performance can be obtained. The content of the inorganic hollow microspheres can be any value between 5wt% and 50wt%, for example, 5wt%, 10wt%, 15wt%, 20wt%, 30wt%, 40wt%, or 50wt%.

[0064] It should be noted that because the density of inorganic hollow microspheres is much lower than that of rubber, the density of the rubber material will significantly decrease as the amount of inorganic hollow microspheres added increases. Specifically, when the inorganic hollow microsphere content is low (less than 5wt%), the density of the diaphragm material is not significantly affected, and the diaphragm still has a relatively high density.

[0065] When the content of inorganic hollow microspheres is too high (greater than 50wt%), the mass proportion of inorganic hollow microspheres is too high, the rubber content is reduced, the material modulus is increased, and the fracture strain is reduced, which will cause the damping layer to lose the inherent soft elasticity of rubber. Due to its excessive mechanical strength, the maximum amplitude that can be achieved by the prepared diaphragm under the same driving force is reduced, which reduces the low-frequency Fr (frequency response) of the sound-generating device. In addition, the excessive addition of inorganic hollow microspheres will significantly reduce the density of the damping layer, and the prepared diaphragm will have low elongation at break and strength, which is prone to reliability issues such as collapse and film rupture.

[0066] Specifically, Table 1 shows the test results for the surface density, loss factor, and elongation at break of the damping layer of composite films with different contents of inorganic hollow microspheres. The inorganic hollow microspheres herein are hollow glass microspheres. It should be noted that hollow glass microspheres are a type of inorganic hollow microspheres, and the use of hollow glass microspheres or other inorganic hollow microspheres can equally demonstrate the role played by the inorganic hollow microspheres in the material.

[0067] As shown in Table 1, with the increase in the mass of hollow glass microspheres added, the surface density of the composite film decreased significantly, and the elongation at break of the damping layer also gradually decreased. Although the loss factor of the composite film gradually increased, when the content of hollow glass microspheres exceeded 40wt%, the loss factor of the composite film began to decrease.

[0068] Among them, when the content of inorganic hollow microspheres is too high, the increase in inorganic hollow microspheres will lead to an increase in material interface defects, and the surface density of the composite film will decrease gently. In addition, an excessively high content of inorganic hollow microspheres will cause the elongation at break of the damping layer to decrease significantly. The damping of the composite film tends to increase first and then decrease with the increase in the amount of inorganic hollow microspheres added. The addition of an appropriate amount of inorganic hollow microspheres can make the inorganic hollow microspheres and the rubber interface tightly bonded. When sound waves are incident on the interior of the material, a large number of longitudinal waves undergo wave mode transformation at the interface, thereby increasing losses and increasing the damping of the composite film. However, when the amount of inorganic hollow microspheres added is too large, there are a large number of defects in the interface between the inorganic hollow microspheres and the rubber, resulting in a decrease in the damping of the composite film.

[0069] Table 1

[0070] Hollow glass microsphere addition amount (wt%) 0 5 10 40 50 <![CDATA[Composite film areal density (g / m 2 )]]> 120 90 70 60 55 Elongation at break of damping layer (%) 485 401 350 230 150 Composite film loss factor 0.02 0.08 0.12 0.26 0.09

[0071] Therefore, by using a damping layer prepared by adding inorganic hollow microbeads accounting for 5wt% to 50wt% of the total amount of basic rubber latex as the diaphragm material, the density and strength of the diaphragm can be taken into account at the same time, so that the composite membrane has appropriate damping, which can not only suppress the polarization of the diaphragm and reduce the distortion of the sound-emitting device, but also make the mechanical properties of the diaphragm superior, meeting the requirements for the acoustic performance and reliability of the diaphragm.

[0072] The sound-producing device of the present application may be a loudspeaker, comprising a vibration system and a magnetic circuit system that cooperates with the vibration system. The vibration system includes the diaphragm provided by the present application, which may be a ring-shaped diaphragm or a flat diaphragm. Loudspeakers with the diaphragm of the present application can have advantages such as good sound quality and durability.

[0073] like Figure 1 As shown in FIG, the diaphragm of the present application and a conventional rubber diaphragm are applied to a loudspeaker, and the acoustic performance of the loudspeaker is tested to obtain the test curves (SPL curves) of the loudness of the diaphragm of the present application and the conventional rubber diaphragm at different frequencies. Among them, the solid line b is the test curve of the loudspeaker with the diaphragm provided in the embodiment of the present application, and the dotted line a is the test curve of the loudspeaker with the conventional rubber diaphragm (without adding hollow glass microbeads). Figure 1 As shown, the mid-frequency sensitivity of the loudspeaker using the diaphragm according to the embodiment of the present application is significantly improved compared to conventional rubber diaphragms.

[0074] like Figure 2 As shown, the diaphragm of the present application and the cloth-impregnated rubber diaphragm are applied to a loudspeaker, and the acoustic performance of the loudspeaker is tested to obtain the harmonic distortion test curves of the diaphragm of the present application and the cloth-impregnated rubber diaphragm. Among them, the solid line b is the test curve of the diaphragm provided in the embodiment of the present application, and the dotted line a is the test curve of the cloth-impregnated rubber diaphragm (without adding hollow glass microbeads). It can be seen from the THD curve that the low-frequency distortion of the loudspeaker using the diaphragm of the embodiment of the present application is much lower than that of the loudspeaker using the conventional cloth-impregnated rubber diaphragm.

[0075] The inorganic hollow microspheres herein are hollow glass microspheres. It should be noted that hollow glass microspheres are a type of inorganic hollow microspheres. The use of hollow glass microspheres or other inorganic hollow microspheres can also reflect the role played by inorganic hollow microspheres in the material.

[0076] That is to say, the loudspeaker using the diaphragm of the embodiment of the present application has higher loudness and listening comfort.

[0077] According to one embodiment of the present application, the surface density of the woven fabric layer is 10 g / m 2 ~150g / m 2 The surface density of the composite film is 30g / m 2 ~300g / m 2 .

[0078] That is to say, in the process of preparing the diaphragm, the surface density of the fabric layer can be selected, and the surface density of the fabric layer can be between 10g / m 2 ~150g / m 2 The surface density of the fabric layer can be selected within the range of 20 g / m 2 ~90g / m 2 By adding inorganic hollow microspheres to the base rubber latex to form a modified rubber latex, and then by adjusting the amount of inorganic hollow microspheres added, the modified rubber latex is coated on the woven fabric layer to form a composite film. The surface density of the composite film can be controlled at 30g / m 2 ~300g / m 2 In the range, preferably, 30g / m 2 ~100g / m 2 For example, the surface density of the composite film can be 30g / m 2 , 50g / m 2 , 80g / m 2 , 100g / m 2 or 300g / m 2 The surface density of the composite film within this range can make the composite film have appropriate strength and ensure that the composite film has high damping.

[0079] In a specific embodiment of the present application, the thickness of the composite membrane is 0.05mm to 0.35mm. That is, the thickness of the composite membrane formed by applying the damping layer to the woven fabric layer can be in the range of 0.05mm to 0.35mm. For example, the thickness of the composite membrane can be 0.05mm, 0.1mm, 0.15mm, 0.25mm or 0.35mm. By controlling the thickness of the modified rubber latex coating and the thickness of the woven fabric layer, a composite membrane of appropriate thickness can be obtained, which not only ensures the mechanical strength of the composite membrane, but also enables the diaphragm to have an appropriate loss factor, thereby ensuring the acoustic performance of the sound-generating device.

[0080] According to one embodiment of the present application, the modulus of the composite film is 300 MPa to 1500 MPa.

[0081] That is to say, by adding inorganic hollow microbeads to the base rubber latex to form a modified rubber latex, and then adjusting the amount of inorganic hollow microbeads added, the modified rubber latex is coated on the woven fabric layer to form a composite film. The modulus of the composite film can be controlled within the range of 300MPa to 1500MPa, which can ensure the mechanical strength of the composite film and thus ensure the performance of the diaphragm.

[0082] According to one embodiment of the present application, the damping of the composite film is greater than 0.08.

[0083] Specifically, inorganic hollow microspheres have high strength, and when filled into rubber, the material's hardness is significantly increased. Therefore, at the same hardness, low-density rubber requires far less reinforcing agent than ordinary rubber. This means the damping layer has a higher rubber content, increased intermolecular entanglement, and greater internal friction, resulting in superior damping performance. The composite film of this application has a damping greater than 0.08. For example, the damping can be 0.08, 0.12, 0.14, 0.15, 0.16, 0.17, or 0.18, etc.

[0084] Therefore, the diaphragm made of a diaphragm material with a higher damping value has a lower impedance curve, which can improve the damping property of the diaphragm. The vibration system can effectively suppress the polarization phenomenon during the vibration and sound generation process, and the consistency of the vibration system is better.

[0085] Furthermore, the loss factor can be adjusted in conjunction with the diaphragm thickness to further optimize its performance. Generally, the higher the loss factor, the better the material's damping properties. Improving the damping properties of the diaphragm material helps reduce polarization during vibration, lowering product distortion and improving audio quality.

[0086] In a specific embodiment of the present application, the material of the woven fabric layer is plain woven fabric, which is any one of plain woven cotton fabric, plain woven PET fabric and plain woven natural silk fabric. Figure 3 The figure shows the structure of plain woven fabric.

[0087] like Figure 4 As shown in FIG, the modified rubber latex is coated on one side of the fabric layer, and after forming, a composite film containing a damping layer on one side of the fabric layer is obtained. Figure 5 As shown, modified rubber latex is coated on both sides of the woven fabric layer, and after molding, a composite film containing damping layers on both sides of the woven fabric layer is obtained. In the figure, the white circles are inorganic hollow microbeads, and the black mesh circles are the strands of the woven fabric layer.

[0088] According to one embodiment of the present application, the plain woven fabric includes a plurality of thread bundles, with gaps between adjacent thread bundles, and the size of the gaps is 10 μm to 300 μm. Preferably, the size of the gaps is 20 μm to 200 μm.

[0089] If the gap between adjacent strands is too large, the composite film will have low strength. If the gap is too small, the damping layer content will increase, making the composite film heavier and having lower damping. If the gap between adjacent strands is too large or too small, the bond between the fabric layer and the damping layer will be affected, not only failing to achieve the reinforcement effect, but also reducing the mechanical properties of the composite film.

[0090] In some specific embodiments of the present application, the gap is filled with modified rubber latex. That is, when the modified rubber latex is applied to the fabric layer, a portion of the modified rubber latex enters the gap and fills it, reducing the weight of the composite membrane. Because the gap is of appropriate size, the fabric layer and the damping layer can be tightly bonded, enhancing the mechanical properties of the composite membrane and improving its damping.

[0091] According to one embodiment of the present application, each harness includes a plurality of threads, with the number of threads ranging from 10 to 40 and the thread diameter ranging from 5 μm to 25 μm. By controlling the number and diameter of the threads, a woven fabric layer of suitable quality and strength can be obtained to facilitate combination with the damping layer to form a composite membrane.

[0092] In some specific embodiments of the present application, the plain woven fabric is immersed in a thermosetting resin solution and treated with the thermosetting resin to obtain a woven fabric layer, wherein the thermosetting resin includes a thermosetting phenolic resin and a thermosetting epoxy resin.

[0093] That is to say, the woven fabric layer needs to be immersed in a thermosetting resin solution and treated with the thermosetting resin before the modified rubber latex can be applied to the woven fabric layer. Specifically, the woven fabric is immersed in the thermosetting resin solution and then taken out and dried.

[0094] According to one embodiment of the present application, the coating method is dip coating, blade coating, roller coating, or spray coating. In other words, the coating method can be selected based on the selected material to achieve a good bond between the damping layer and the fabric layer. This also increases the selectivity of production methods.

[0095] In some specific embodiments of the present application, the base rubber latex is one or more of natural rubber latex, styrene-butadiene rubber latex, butadiene rubber latex, isoprene rubber latex, chloroprene rubber latex, butyl rubber latex, nitrile rubber latex, chlorinated nitrile rubber latex, ethylene-propylene rubber latex, silicone rubber latex, fluororubber latex, polyurethane rubber latex, acrylate rubber latex, chlorosulfonated polyethylene rubber latex, epichlorohydrin rubber latex, polysulfide rubber latex, and ethylene-vinyl acetate rubber latex. There are multiple options for the base rubber latex, which can ensure the stability of the diaphragm in high temperature environments.

[0096] In summary, according to the method for preparing the diaphragm of the sound-emitting device of the embodiment of the present application, the diaphragm is prepared by using a damping layer and a woven fabric layer added with inorganic hollow microbeads as raw materials, so that the diaphragm can have excellent damping performance and resilience, the vibration system can effectively suppress the polarization phenomenon during the vibration and sound generation process, the consistency of the vibration system is better, and the transient distortion of the sound-emitting device is effectively suppressed, so that the sound-emitting device made of the diaphragm of the present application has good acoustic performance.

[0097] It should be noted that the diaphragm provided herein can be incorporated into any sound-generating device, such as the following typical sound-generating device: It includes a vibration system and a magnetic circuit system that cooperates with the vibration system. The vibration system includes a diaphragm and a voice coil coupled to one side of the diaphragm. When the sound-generating device is in operation, the voice coil is energized and, under the influence of the magnetic field of the magnetic circuit system, vibrates up and down, driving the diaphragm to vibrate. This vibration of the diaphragm produces sound.

[0098] According to an embodiment of the third aspect of the present application, a sound-producing device includes a vibration system and a magnetic circuit system coordinated with the vibration system. The vibration system includes a diaphragm and a voice coil coupled to one side of the diaphragm. The magnetic circuit system drives the voice coil to vibrate, thereby driving the diaphragm to produce sound. The diaphragm is the diaphragm of the aforementioned embodiment. Specifically, when the sound-producing device is in operation, after power is applied to the voice coil, the magnetic force of the magnetic circuit system causes the voice coil to vibrate up and down, driving the diaphragm to vibrate. The vibration of the diaphragm produces sound.

[0099] like Figure 6 and Figure 7 As shown, the sound-generating device includes a diaphragm 15 prepared according to the above-described embodiment of the present application. The diaphragm 15 can be composed of a rim portion 151 and a dome portion 152. The composite layer can be applied to the rim portion 151 of the diaphragm. Those skilled in the art can make corresponding adjustments based on actual product requirements, such as making the rim portion 151 convex toward the voice coil 11, positioning the dome portion 152 on the lower surface of the rim portion 151, and adding a centering support to the vibration system.

[0100] like Figure 8 and Figure 9 As shown, the sound-emitting device 100 according to the fourth embodiment of the present application includes a shell 10 and a magnetic circuit system 14 and a vibration system arranged in the shell 10. The vibration system includes a voice coil 11, a first diaphragm 12 and a second diaphragm 13. The top of the voice coil 11 is connected to the first diaphragm 12. The magnetic circuit system 14 drives the voice coil 11 to vibrate to drive the first diaphragm 12 to make sound. The two ends of the second diaphragm 13 are respectively connected to the bottom of the shell 10 and the voice coil 11. The second diaphragm 13 is the diaphragm of the above embodiment.

[0101] That is, the sound-generating device 100 according to the embodiment of the present application may further include two diaphragms prepared according to the above-described embodiment of the present application, namely, a first diaphragm 12 and a second diaphragm 13. The first diaphragm 12 can be used to vibrate and produce sound, and the second diaphragm 13 can be used to balance the vibration of the voice coil 11. Specifically, when the sound-generating device 100 is in operation, after the voice coil 11 is energized, the magnetic field force of the magnetic circuit system 14 causes the voice coil 11 to vibrate up and down, thereby driving the first diaphragm 12 to vibrate. The vibration of the first diaphragm 12 can produce sound. The second diaphragm 13 can also vibrate up and down following the voice coil 11. Since the two ends of the second diaphragm 13 are respectively connected to the housing 10 and the bottom of the voice coil 11, the second diaphragm 13 can balance the vibration of the voice coil 11, prevent polarization of the voice coil 11, and thus improve the sound quality of the sound-generating device 100.

[0102] It should be noted that the first diaphragm 12 and the second diaphragm 13 may simultaneously adopt the diaphragms of the above embodiment of the present application, or one of the first diaphragm 12 and the second diaphragm 13 may adopt the diaphragm of the above embodiment of the present application. The present application does not impose any specific restrictions on this.

[0103] The diaphragm of the sound-generating device of the present application is described in detail below with reference to specific embodiments.

[0104] Example 1

[0105] Weigh the base rubber latex and hollow glass microspheres by mass. The base rubber latex includes: 100 parts of nitrile rubber, 30 parts of carbon black, 4 parts of zinc oxide, 1.5 parts of stearic acid, 2 parts of vulcanization accelerator, and 1.8 parts of sulfur; and 15 parts of hollow glass microspheres. The average particle size of the hollow glass microspheres is 25 μm to 30 μm, and the density is 0.35 g / cm 3 , compressive strength 40MPa. After adding hollow glass microspheres to the basic rubber latex, a modified rubber latex is obtained, and the modified rubber latex is coated on one side of the woven fabric layer. After the modified rubber latex is dried on the woven fabric layer, a damping layer is formed to obtain a composite membrane material. The composite membrane material can then be placed on a molding machine for hot pressing. The molding temperature can be 200℃~260℃, and the holding time can be 6S~15S. After the holding is completed, the mold is opened to obtain a composite membrane. Finally, after waiting for the composite membrane to cool, the composite membrane is punched or laser cut according to the diaphragm design requirements to obtain a diaphragm.

[0106] Comparative Example 1

[0107] The difference between Comparative Example 1 and Example 1 is that hollow glass microspheres are not added to the base rubber latex, and the other preparation methods are exactly the same as those of Example 1.

[0108] Test indicators: composite film surface density, loss factor, modulus

[0109] Table 2 shows the performance test results of the diaphragm materials of Comparative Example 1 and Example 1, reflecting the effect of adding inorganic hollow microspheres on the density, loss factor, and modulus of the diaphragm materials. The inorganic hollow microspheres here are hollow glass microspheres. It should be noted that hollow glass microspheres are a type of inorganic hollow microspheres. Using hollow glass microspheres or other inorganic hollow microspheres can also reflect the role played by inorganic hollow microspheres in the material.

[0110] Test method:

[0111] (1) Tensile properties: The tensile strength and elongation at break were determined according to ASTM D412-2016. The specimens were dumbbell-shaped, the tensile rate was 500 mm / min, and each group of samples was tested 5 times to obtain the average value.

[0112] (2) The room temperature loss factor was determined by dynamic mechanical testing (DMA) according to ASTM D5026-15, with a tensile fixture, a test temperature range of -50°C to 200°C, a heating rate of 3°C / min, and three tests per group of samples to obtain the average value.

[0113] Table 2

[0114] Case <![CDATA[Composite film areal density (g / cm 3 )]]> loss factor Modulus (MPa) Example 1 80 0.14 837 Comparative Example 1 110 0.06 802

[0115] As can be seen from Table 2, due to the addition of hollow glass microspheres, the surface density of the composite film is significantly reduced, the loss factor of the diaphragm material is significantly improved, and the modulus does not change much. In other words, the diaphragm of the present application has excellent mechanical properties, which can fully meet the requirements of diaphragm processing mechanics, and the diaphragm product is not prone to reliability problems such as film breakage during use. Since the cavity resonance inside the inorganic hollow microspheres can absorb sound waves with longer wavelengths, the damping of the diaphragm material can be effectively improved. Since the modulus of the diaphragms of Example 1 and Comparative Example 1 is not much different, the F0 (resonance frequency) of the diaphragm made in the embodiment of the present application is stable.

[0116] Therefore, compared with conventional composite membranes, the composite membrane with added inorganic hollow microbeads has lower weight and higher damping, which can reduce the vibration mass of the vibration system, ensure the acoustic stability of the sound-generating device, and make the sound-generating device have lower distortion in the low-frequency state.

[0117] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A diaphragm of a sound-generating device, characterized in that: The diaphragm includes a damping layer and a woven fabric layer, at least one side of the woven fabric layer is coated with the damping layer, and the damping layer includes base rubber and inorganic hollow microspheres. The particle size of the inorganic hollow microspheres is 10 μm to 100 μm, and the distribution density of the inorganic hollow microspheres in the damping layer is 0.15 g / cm 3 ~0.9g / cm 3 The compressive strength of the inorganic hollow microspheres is ≥10 MPa, and the content of the inorganic hollow microspheres accounts for 5wt% to 50wt% of the total amount of the base rubber latex.

2. The diaphragm of the sound-generating device according to claim 1, wherein: The density of the diaphragm is 0.5 g / cm 3 ~1.1g / cm 3 .

3. A method for preparing a diaphragm of a sound-generating device according to claim 1 or 2, characterized in that: The preparation method comprises: adding inorganic hollow microspheres to a base rubber latex to obtain a modified rubber latex, coating the modified rubber latex on at least one side of a woven fabric layer, and forming a damping layer on the woven fabric layer after drying to obtain a composite membrane material; Hot pressing the composite film material to obtain a composite film; The composite film is cut to obtain a diaphragm material.

4. The method for preparing a diaphragm of a sound-generating device according to claim 3, wherein the surface density of the woven fabric layer is 10 g / m 2 ~150g / m 2 The surface density of the composite film is 30g / m 2 ~300g / m 2 .

5. The method for preparing the diaphragm of the sound-generating device according to claim 3, characterized in that: The composite film has a thickness of 0.05 mm to 0.35 mm.

6. The method for preparing a diaphragm of a sound-generating device according to claim 3, wherein: The modulus of the composite film is 300 MPa to 1500 MPa.

7. The method for preparing a diaphragm of a sound-generating device according to claim 3, characterized in that: The damping of the composite film is greater than 0.

08.

8. The method for preparing a diaphragm of a sound-generating device according to claim 3, wherein: The material of the woven fabric layer is plain woven fabric, and the plain woven fabric is any one of plain woven cotton fabric, plain woven PET fabric and plain woven natural silk fabric.

9. The method for preparing a diaphragm of a sound-generating device according to claim 8, characterized in that: The plain woven fabric includes a plurality of wire bundles, and there are gaps between adjacent wire bundles. The size of the gaps is 10 μm to 300 μm.

10. The method for preparing a diaphragm of a sound-generating device according to claim 9, characterized in that: The gap is filled with the modified rubber latex.

11. The method for preparing a diaphragm of a sound-generating device according to claim 9, wherein: Each of the wire bundles includes a plurality of wires, the number of the wires is 10 to 40, and the diameter of the wires is 5 μm to 25 μm.

12. The method for preparing a diaphragm of a sound-generating device according to claim 8, wherein: Before applying the modified rubber latex to the woven fabric layer, the preparation method further comprises: immersing the plain woven fabric in a thermosetting resin solution for thermosetting resin treatment to obtain the woven fabric layer, wherein the thermosetting resin comprises a thermosetting phenolic resin and a thermosetting epoxy resin.

13. The method for preparing a diaphragm of a sound-generating device according to claim 3, characterized in that: The coating method is dipping, blade coating, roller coating or spraying.

14. The method for preparing a diaphragm of a sound-generating device according to claim 3, wherein: The base rubber latex is one or more of natural rubber latex, styrene-butadiene rubber latex, butadiene rubber latex, isoprene rubber latex, chloroprene rubber latex, butyl rubber latex, nitrile rubber latex, chlorinated nitrile rubber latex, ethylene-propylene rubber latex, silicone rubber latex, fluororubber latex, polyurethane rubber latex, acrylate rubber latex, chlorosulfonated polyethylene rubber latex, epichlorohydrin rubber latex, polysulfide rubber latex and ethylene-vinyl acetate rubber latex.

15. A sound-generating device, characterized in that: It includes a vibration system and a magnetic circuit system coordinated with the vibration system, the vibration system includes a diaphragm and a voice coil coupled to one side of the diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the diaphragm to make sound, and the diaphragm is the diaphragm described in any one of claims 1-2.

16. A sound-generating device, characterized in that: It includes a shell and a magnetic circuit system and a vibration system arranged in the shell, the vibration system includes a voice coil, a first diaphragm and a second diaphragm, the top of the voice coil is connected to the first diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the first diaphragm to make sound, the two ends of the second diaphragm are respectively connected to the shell and the bottom of the voice coil, and the second diaphragm is the diaphragm according to any one of claims 1-2.

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