Vibrating diaphragm, vibrating diaphragm assembly, sound production device and electronic equipment

Abstract

The invention discloses a vibrating diaphragm, a vibrating diaphragm assembly, a sound production device and electronic equipment. The vibrating diaphragm comprises an elastomer layer composed of a modified polystyrene-poly (ethylene-butylene)-polystyrene block copolymer, the modified polystyrene-poly (ethylene-butylene)-polystyrene block copolymer contains an epoxy group, a benzene ring and an olefin chain segment # imgabs0 #, x, y and n are positive integers, x is 1-8, y is 1-10, n is 1-10, and n is 1-10. The molar ratio of the epoxy group to the benzene ring is 0.05-5%, the olefin chain segment accounts for 10-40% of the total mass of the copolymer, and the loss factor of the elastomer layer at 20-30 DEG C is 0.07-2.5. The olefin chain segment can improve the loss factor of the elastomer layer so as to improve the damping of the vibrating diaphragm, thereby facilitating the reduction of the distortion of the sound production device using the vibrating diaphragm and the improvement of the sound quality of the sound production device, and the epoxy group is suitable for reacting with the dome to form a chemical bond, thereby generating a strong bonding force, and enabling the bonding force between the vibrating diaphragm and the dome to be strong.

Description

Technical Field

[0001] The present invention relates to the technical field of electroacoustic conversion, and more specifically, to a diaphragm, a diaphragm assembly, a sound-generating device and an electronic device. Background Art

[0002] In the field of acoustics, rubber diaphragms are often used in sound-generating devices, especially liquid silicone rubber, which has the advantages of simple production process and good comprehensive performance, and is usually used for diaphragm materials. Liquid silicone rubber diaphragms have a wide temperature resistance range, good resilience, and can be integrally formed. With the increasing requirements for high power and waterproofing, liquid silicone rubber diaphragms have been promoted in the field of speakers. However, the main chain of liquid silicone rubber is mainly Si-O-Si, and the side group is mainly -CH3. It has a regular structure, small steric hindrance, small intermolecular friction, and low loss factor. Therefore, the damping of the liquid silicone rubber diaphragm is low, and the sound-generating device using this diaphragm has high distortion and poor sound quality.

[0003] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Summary of the invention

[0004] An object of the present invention is to provide a new technical solution for a diaphragm.

[0005] According to a first aspect of the present invention, a diaphragm for a sound-generating device is provided. The diaphragm comprises:

[0006] An elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, wherein the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups, benzene rings and olefin segments Among them, x, y, and n are positive integers, x is 1-8, y is 1-10, the molar ratio of the epoxy group to the benzene ring is 0.05%-5%, the olefin segment accounts for 10%-40% of the total mass of the copolymer, and the loss factor of the elastomer layer between 20°C and 30°C is 0.07-2.5.

[0007] Optionally, the olefin segment accounts for 20%-30% of the total mass of the copolymer.

[0008] Optionally, the elongation at break of the elastomer layer is 100%-800%.

[0009] Optionally, the Young's modulus of the elastomer layer is 15 MPa-700 MPa.

[0010] Optionally, the thickness of the elastomer layer is 10 μm-300 μm.

[0011] Optionally, the density of the elastomer layer is 0.7 g / cm 3 -1.0g / cm3 ; and / or, the glass transition temperature of the elastomer layer is -50°C to 10°C.

[0012] Optionally, the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer is formed by grafting a polystyrene-poly(ethylene-butylene)-polystyrene block copolymer with an active compound containing an epoxy group, wherein the active compound includes at least one of glycidyl methacrylate, 1,2-epoxy-4-vinylcyclohexane and 2,3-epoxypropyltrimethylammonium chloride.

[0013] Optionally, the diaphragm is formed as a single-layer structure, and the diaphragm is composed of a layer of the elastomer layer; or, the diaphragm is formed as a composite layer structure, and the diaphragm includes the elastomer layer and a composite layer, and the composite layer includes engineering plastics and / or elastomer materials.

[0014] According to a second aspect of the present invention, a diaphragm assembly is provided, which comprises a dome and the diaphragm of the above embodiment, wherein the dome is connected to the diaphragm.

[0015] Optionally, the diaphragm and the dome are bonded together via an adhesive layer; or, the diaphragm and the dome are integrally hot-pressed or integrally injection-molded.

[0016] According to a third aspect of the present invention, a sound-generating device is provided. The sound-generating device comprises a vibration system and a magnetic circuit system matched with the vibration system, the vibration system comprises a voice coil and a diaphragm assembly of the above embodiment, the diaphragm assembly is arranged on one side of the voice coil, and the magnetic circuit system can drive the voice coil to vibrate so as to drive the diaphragm assembly to generate sound.

[0017] According to a fourth aspect of the present invention, an electronic device is provided, which includes the sound generating device of the above embodiment.

[0018] One technical effect of the present invention is that the diaphragm includes an elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, and the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups, benzene rings and olefin segments. The olefin segments account for 10%-40% of the total mass of the copolymer, so that the loss factor of the elastomer layer can be increased to improve the damping of the diaphragm, thereby helping to reduce the distortion of the sound-generating device using the diaphragm and improve the sound quality of the sound-generating device. The benzene ring is beneficial to improving the temperature resistance and mechanical properties of the elastomer layer. The epoxy group has a high reactivity and is suitable for reacting with free radicals on the surface of the dome to form chemical bonds, thereby generating a strong adhesive force, thereby making the adhesion between the diaphragm and the dome stronger, and the epoxy group will produce a ring-opening reaction, thereby obtaining a higher adhesive force between the diaphragm and the dome through intramolecular covalent bonds.

[0019] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0021] Figure 1 It is a partial cross-sectional view of a sound-generating device according to an embodiment of the present invention.

[0022] Figure 2 It is a schematic structural diagram of a diaphragm according to an embodiment of the present invention.

[0023] Figure 3 It is a total harmonic distortion curve diagram of a sound-generating device according to an embodiment of the present invention.

[0024] Reference numerals:

[0025] 100, sound-generating device; 110, housing; 120, diaphragm assembly; 121, diaphragm; 122, dome; 130, voice coil; 140, permanent magnet. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0027] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0028] 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 as part of the specification.

[0029] 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.

[0030] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0031] The present invention provides a diaphragm 121 for a sound-generating device 100. The diaphragm 121 includes an elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, wherein the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups, benzene rings and olefin segments. Among them, x, y, and n are positive integers, x is 1-8, y is 1-10, the molar ratio of the epoxy group to the benzene ring is 0.05%-5%, the olefin segment accounts for 10%-40% of the total mass of the copolymer, and the loss factor of the elastomer layer between 20°C and 30°C is 0.07-2.5.

[0032] In an embodiment of the present invention, the diaphragm 121 includes an elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, wherein the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups, benzene rings and olefin segments. The olefin segments account for 10%-40% of the total mass of the copolymer, thereby increasing the loss factor of the elastomer layer to increase the damping of the diaphragm 121, thereby facilitating the reduction of the distortion of the sound-generating device 100 using the diaphragm 121 and improving the sound quality of the sound-generating device 100. The benzene ring is beneficial to improving the temperature resistance and mechanical properties of the elastomer layer. The epoxy group has high reactivity and is suitable for reacting with free radicals on the surface of the dome 122 to form chemical bonds, thereby generating a strong adhesive force, thereby making the adhesive force between the diaphragm 121 and the dome 122 stronger, and the epoxy group will produce a ring-opening reaction, thereby obtaining a higher adhesive force between the diaphragm 121 and the dome 122 through intramolecular covalent bonds.

[0033] In this embodiment, the elastomer layer is composed of modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer (modified SEBS) having the formula:

[0034] The modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups, benzene rings and olefin segments.

[0035] In this embodiment, the olefin segments have strong winding ability and form a large steric hindrance. When the material is subjected to external force, it can consume more energy, so that the diaphragm 121 has good damping properties. The olefin segments account for 10%-40% of the total mass of the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, which can improve the loss factor of the elastomer layer, thereby effectively improving the damping of the diaphragm 121. When the content of the olefin segments is too little, the loss factor of the elastomer layer is low, which will result in low damping performance of the diaphragm 121 and cannot meet the product use requirements. When the content of the olefin segments is too much, since the benzene ring is generally located at the end of the modified SEBS, and the content of the end-capped benzene ring is fixed, that is, when the content of the olefin segments is too much, the proportion of the benzene ring content will be too low, which will cause the temperature resistance and mechanical properties of the diaphragm 121 to decrease. Therefore, the olefin segment accounts for 10%-40% of the total mass of the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, which can not only ensure that the damping performance of the diaphragm 121 meets the use requirements, but also avoid the benzene ring content being too low, which will lead to a decrease in the temperature resistance and mechanical properties of the diaphragm 121.

[0036] For example, the olefin segment can account for 10%, 20%, 30% or 40% of the total mass of the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer. The above values ​​can ensure that the damping performance of the diaphragm 121 meets the use requirements, and can avoid the benzene ring content being too low, which will lead to a decrease in the temperature resistance and mechanical properties of the diaphragm 121.

[0037] The olefin segments account for 20%-30% of the total mass of the copolymer, which is beneficial to further ensure that the damping performance of the diaphragm 121 meets the use requirements, and can avoid the content of benzene rings being too low, which leads to a decrease in the temperature resistance and mechanical properties of the diaphragm 121.

[0038] In this embodiment, the loss factor of the elastomer layer between 20°C and 30°C is 0.07-2.5. That is, the loss factor of the elastomer layer at room temperature is 0.07-2.5, so that the diaphragm 121 has good damping properties at room temperature, which is beneficial to reduce the distortion of the sound-generating device 100 using the diaphragm 121 and improve the sound quality of the sound-generating device 100. The loss factor of the elastomer layer can be adjusted by adjusting the mass fraction of the olefin segment in the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer. For example, the loss factor can be 0.07, 0.09, 0.1, 0.25, 0.6, 0.8, 1.0 or 1.3, etc.

[0039] Among them, at 23°C, the loss factor of the elastomer layer is 0.09-1.3.

[0040] In this embodiment, the modified SEBS contains epoxy groups and benzene rings, and the molar ratio of epoxy groups to benzene rings is in the range of 0.05%-5%. The benzene rings are generally located at the end of the modified SEBS, and the content of the end-capped benzene rings is fixed. Therefore, when the molar ratio of epoxy groups to benzene rings is too low, that is, the content of epoxy groups is too low, the intramolecular covalent bond content of the epoxy groups that can produce a ring-opening reaction is low, resulting in too low adhesion between the diaphragm 121 and the ball top 122; and when the molar ratio of epoxy groups to benzene rings is too high, the content of epoxy groups is too high, and the temperature required for the integral molding of the diaphragm 121 and the ball top 122 is high, resulting in reduced processing efficiency. Therefore, the molar ratio of epoxy groups to benzene rings is in the range of 0.05%-5%, so that the diaphragm 121 and the ball top 122 can have a high adhesion, and the temperature of the integral molding of the diaphragm 121 and the ball top 122 can be avoided to be too high, which affects the processing efficiency.

[0041] For example, the molar ratio of epoxy groups to benzene rings can be 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4% or 5%, etc. The above values ​​can make the bonding force between the diaphragm 121 and the dome 122 higher and facilitate the integral molding of the diaphragm 121 and the dome 122.

[0042] In a specific embodiment of the present invention, the elongation at break of the elastomer layer is 100%-800%.

[0043] In this embodiment, the modified SEBS is a thermoplastic elastomer, and its molecular structure is composed of a polystyrene hard segment and a polyolefin soft segment. This block copolymer structure enables the elastomer layer composed of the modified SEBS to have good elasticity, flexibility and high elongation at break. That is, the elongation at break of the elastomer layer can be 100%-800%. When the elongation at break of the elastomer layer is too low, the diaphragm 121 is easily damaged during molding. When the elongation at break of the elastomer layer is too high, it helps to improve the sensitivity and response speed of the diaphragm 121, which is beneficial to improving the performance of the sound-generating device 100. However, excessive elongation at break may also cause the diaphragm 121 to fatigue easily after long-term use, thereby affecting the durability and stability of the diaphragm assembly 120. The elongation at break of the elastomer layer is 100%-800%, which makes the diaphragm 121 not easy to break, and the diaphragm assembly 120 has high durability and stability.

[0044] For example, the elongation at break of the elastomer layer can be 100%, 150%, 200%, 300%, 400%, 500%, 600%, 700% or 800%, etc. The above values ​​can make the diaphragm 121 not easily damaged, and the diaphragm assembly 120 has high durability and stability.

[0045] Among them, when the elongation at break of the elastic layer is 150%-500%, it is beneficial to further improve the durability and stability of the diaphragm assembly 120.

[0046] In a specific embodiment of the present invention, the Young's modulus of the elastomer layer is 15 MPa-700 MPa.

[0047] In this embodiment, the Young's modulus of the elastomer layer is 15MPa-700MPa. When the Young's modulus of the elastomer layer is too low, the diaphragm 121 is easily damaged during molding, and the F0 (the lowest vibration frequency of the diaphragm 121 that the product can make sound) required by the product cannot be achieved. It can only be achieved by thickening, but the increase in thickness will lead to an increase in the mass of the diaphragm 121, which will lose its vibration space and reduce the sensitivity of the mass control area. When the Young's modulus is too high, the flexibility and resilience of the material deteriorate. In order to obtain high loudness, the product requires the diaphragm 121 to have a large displacement. At this time, the excessively high Young's modulus will inevitably bring adverse effects. The Young's modulus of the elastomer layer is 15MPa-700MPa, which makes the diaphragm 121 not easy to be damaged, and has good flexibility and resilience.

[0048] For example, the Young's modulus of the elastomer layer may be 15 MPa, 30 MPa, 50 MPa, 100 MPa, 150 MPa, 200 MPa, 300 MPa, 400 MPa, 500 MPa or 600 MPa, etc. The above values ​​make the diaphragm 121 not easily damaged and have good flexibility and resilience.

[0049] The Young's modulus of the elastomer layer may be 30 MPa-150 MPa, which is also beneficial to further improve the performance of the diaphragm 121 .

[0050] In a specific embodiment of the present invention, the thickness of the elastomer layer is 10 μm-300 μm.

[0051] In this embodiment, the thickness of the elastomer layer is 10μm-300μm. When the thickness of the elastomer layer is too thin, the rigidity of the diaphragm 121 will be insufficient and the film making will be difficult. When the thickness of the elastomer layer is too thick, the mass of the diaphragm 121 will increase, which will easily lead to a decrease in the sensitivity of the diaphragm 121. Moreover, if the thickness of the elastomer layer is too large, it will occupy the vibration space of the diaphragm 121, thereby affecting the sound effect of the sound-generating device 100. The thickness of the elastomer layer is 10μm-300μm, which can make the diaphragm 121 have good rigidity, reduce the difficulty of film making, and help to reduce the mass of the diaphragm 121 and improve the sensitivity of the diaphragm 121.

[0052] For example, the thickness of the elastic layer may be 10 μm, 20 μm, 50 μm, 100 μm, 150 μm, 200 μm or 300 μm, etc. The above values ​​can make the diaphragm 121 have good rigidity, reduce the difficulty of film making, and help reduce the mass of the diaphragm 121 and improve the sensitivity of the diaphragm 121.

[0053] The thickness of the elastomer layer may be 20um-150um, which is beneficial to further make the diaphragm 121 have good rigidity, reduce the difficulty of film making, reduce the mass of the diaphragm 121, and improve the sensitivity of the diaphragm 121.

[0054] In a specific embodiment of the present invention, the density of the elastomer layer is 0.7 g / cm 3 -1.0g / cm 3 ; and / or, the glass transition temperature of the elastomer layer is -50°C to 10°C.

[0055] In this example, in this embodiment, the density of the elastomer layer is 0.7 g / cm 3 -1.0g / cm 3 When the density of the elastomer is too low, the mechanical strength of the diaphragm 121 will be reduced. During use, the diaphragm 121 is easily damaged and difficult to meet the use requirements. If the density of the elastomer layer is too high, it will affect the acoustic performance of the diaphragm 121. The density of the elastomer layer is 0.7g / cm 3 -1.0g / cm 3 , which can improve the mechanical strength of the diaphragm 121 and avoid affecting the acoustic performance of the diaphragm 121.

[0056] For example, the density of the elastomer layer may be 0.7 g / cm 3 , 0.8g / cm 3 , 0.9g / cm 3 , 1.0g / cm 3 or 1.1 g / cm 3 The above values ​​can both increase the mechanical strength of the diaphragm 121 and avoid affecting the acoustic performance of the diaphragm 121.

[0057] The density of the elastomer layer can be 0.85 g / cm 3 -0.95g / cm 3 , which is beneficial to further improve the mechanical strength of the diaphragm 121 while avoiding affecting the acoustic performance of the diaphragm 121.

[0058] In this embodiment, the glass transition temperature (Tg) is the temperature at which the material changes from a glassy state to a highly elastic state. When the glass transition temperature of the elastomer layer is too low, the Young's modulus of the diaphragm 121 will rise rapidly, causing the rigidity of the diaphragm 121 to be too high, the F0 of the diaphragm 121 to increase significantly, and the toughness of the diaphragm 121 to decrease, which is prone to the risk of fracture. When the glass transition temperature is too high, the diaphragm 121 may be more in the glassy state at low working environment temperatures, affecting the mechanical properties of the diaphragm 121. The glass transition temperature of the elastomer layer is -50°C to -10°C, which can make the diaphragm 121 have high flexibility and good sensitivity in the high frequency band.

[0059] For example, the glass transition temperature of the elastomer layer can be -50°C, -40°C, -30°C, -25°C, -20°C, -15°C or -10°C, etc. The above values ​​can make the diaphragm 121 have high flexibility and good sensitivity in the high frequency band.

[0060] The glass transition temperature of the elastic layer may be -30° C. to -15° C. This is beneficial for further making the diaphragm 121 have higher flexibility and better sensitivity in the high frequency band.

[0061] In a specific embodiment of the present invention, the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer is formed by grafting a polystyrene-poly(ethylene-butylene)-polystyrene block copolymer with an active compound containing an epoxy group, wherein the active compound includes at least one of glycidyl methacrylate, 1,2-epoxy-4-vinylcyclohexane and 2,3-epoxypropyltrimethylammonium chloride.

[0062] In this embodiment, polystyrene-poly(ethylene-butylene)-polystyrene block copolymer (SEBS) is grafted with glycidyl methacrylate containing epoxy groups to form modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer (modified SEBS). That is,

[0063]

[0064] Among them, the grafting reaction is also called graft copolymerization or graft (co)polymerization. SEBS grafting is a free radical reaction, and the epoxy group is grafted onto the SEBS molecular chain in the form of monomers and oligomers, and the grafting position is on the unhydrogenated double bond.

[0065] Of course, the active compound containing epoxy groups may include one or more of glycidyl methacrylate, 1,2-epoxy-4-vinylcyclohexane and 2,3-epoxypropyltrimethylammonium chloride. Those skilled in the art may determine the actual situation, and no specific limitation is made here.

[0066] In a specific embodiment of the present invention, the diaphragm 121 is formed as a single-layer structure, and the diaphragm 121 is composed of a layer of the elastomer layer; or, the diaphragm 121 is formed as a composite layer structure, and the diaphragm 121 includes the elastomer layer and a composite layer, and the composite layer includes engineering plastics and / or elastomeric materials.

[0067] In this embodiment, the diaphragm 121 may be a single-layer structure, that is, the diaphragm 121 is composed of a single-layer elastic layer. The single-layer diaphragm 121 is thinner and lighter, which is beneficial to the miniaturization design of the diaphragm assembly 120.

[0068] Alternatively, the diaphragm 121 may also be a composite layer structure, that is, the diaphragm 121 is composed of an elastomer layer and a composite layer. Among them, the composite layer may be one or both of engineering plastics and elastomer materials. By adding a composite layer, the diaphragm 121 can combine the advantages of the elastomer layer and the composite layer, and can further improve the heat resistance, compression deformation resistance, aging resistance, etc. of the diaphragm 121, and improve the mechanical properties of the diaphragm 121. Among them, engineering plastics include PEEK (polyetheretherketone) and PI (polyimide), etc., and elastomeric materials include TPU (thermoplastic polyurethane elastomer), TPEE (thermoplastic polyester elastomer) and rubber, etc. Of course, the specific material of the composite layer can be determined by those skilled in the art according to the actual situation, and no specific limitation is made here.

[0069] According to a second aspect of the present invention, a diaphragm assembly 120 is provided. The diaphragm assembly 120 comprises a dome 122 and the diaphragm 121 of the above embodiment, wherein the dome 122 is connected to the diaphragm 121 .

[0070] In this embodiment, the diaphragm assembly 120 includes a dome 122 and a diaphragm 121 of the above embodiment, and the diaphragm 121 is connected to the dome 122. By arranging the dome 122 on the diaphragm 121, the strength of the diaphragm 121 can be improved and the acoustic performance of the diaphragm 121 can be optimized. The diaphragm 121 of the present invention includes an elastomer layer composed of a modified polystyrene-poly (ethylene-butylene) -polystyrene block copolymer, and the modified polystyrene-poly (ethylene-butylene) -polystyrene block copolymer contains epoxy groups, benzene rings and olefin segments. The olefin segments account for 10%-40% of the total mass of the copolymer, so that the loss factor of the elastomer layer can be improved to improve the damping of the diaphragm 121, which is beneficial to reduce the distortion of the sound-generating device 100 using the diaphragm assembly 120 and improve the sound quality of the sound-generating device 100.

[0071] The diaphragm 121 and the dome 122 are bonded together by an adhesive layer, for example, the diaphragm 121 and the dome 122 can be bonded together by a hot melt adhesive film, an epoxy resin adhesive layer or an acrylic adhesive film.

[0072] Alternatively, the diaphragm 121 and the dome 122 are integrally hot-pressed or integrally injection-molded. The integral molding temperature of the diaphragm 121 and the dome 122 is 80° C. to 200° C. When the diaphragm 121 and the dome 122 are molded, at the molding temperature, the epoxy groups in the elastomer layer will undergo a ring-opening reaction, thereby obtaining a higher bonding force through intramolecular covalent bonds.

[0073] In this embodiment, the benzene ring is generally located at the end of the modified SEBS, and the content of the end-capped benzene ring is fixed. Therefore, when the molar ratio of the epoxy group to the benzene ring is too low, that is, the content of the epoxy group is too low, the content of the intramolecular covalent bond that the epoxy group can produce a ring-opening reaction is low, resulting in too low adhesion between the diaphragm 121 and the dome 122; and when the molar ratio of the epoxy group to the benzene ring is too high, the content of the epoxy group is too high, and the temperature required for the integral molding of the diaphragm 121 and the dome 122 is high, resulting in reduced processing efficiency. Therefore, the molar ratio of the epoxy group to the benzene ring in the elastomer layer is in the range of 0.05%-5%, which can not only make the diaphragm 121 and the dome 122 have a higher adhesion, but also avoid the temperature of the integral molding of the diaphragm 121 body and the dome 122 being too high to affect the processing efficiency.

[0074] For example, the molar ratio of epoxy groups to benzene rings can be 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4% or 5%, etc. The above values ​​can make the bonding force between the diaphragm 121 and the dome 122 higher and facilitate the integral molding of the diaphragm 121 and the dome 122.

[0075] In addition, between 20°C and 30°C, the ejection force of the diaphragm assembly 120 is 5N-30N. For example, the ejection force of the diaphragm assembly 120 can be 5N-30N at 20°C, 25°C or 30°C. The test method of the ejection force includes:

[0076] a) fixing the diaphragm assembly 120 by using a tool;

[0077] b) Install a top head below the tensile gauge, and place the diaphragm assembly 120 and the top head of the tensile gauge vertically;

[0078] c) Run the dynamometer so that the ejector head vertically contacts the ball top 122 and runs to the position where the diaphragm 121 and the ball top 122 are separated or the diaphragm 121 is damaged, and record the force value of the dynamometer at this time, which is the ejection force.

[0079] The ejection force indicates the size of the bonding force between the diaphragm 121 and the ball top 122. When the ejection force is too low, the bonding force between the diaphragm 121 and the ball top 122 is small, and the reliability of the diaphragm assembly 120 is too low. When the ejection force is too high, the diaphragm 121 needs to contain more epoxy groups. The more epoxy groups there are, the higher the molding temperature of the diaphragm 121 is, which reduces the processing efficiency of the diaphragm 121. The ejection force of the diaphragm assembly 120 is 5N-30N, so that the reliability of the diaphragm assembly 120 is high and the processing efficiency of the diaphragm 121 is high. For example, the ejection force of the diaphragm assembly 120 can be 5N, 10N, 15N, 20N, 25N or 30N, etc. The above values ​​can all make the reliability of the diaphragm assembly 120 high and the processing efficiency of the diaphragm 121 high.

[0080] In this embodiment, the material of the ball top 122 can be carbon fiber, aluminum, aluminum alloy or engineering plastic (PEEK (polyetheretherketone) and PI (polyimide)), etc. The shape of the ball top 122 is circular, rectangular, oval, etc.

[0081] According to a third aspect of the present invention, a sound-generating device 100 is provided. The sound-generating device 100 includes a vibration system and a magnetic circuit system matched with the vibration system, the vibration system includes a voice coil 130 and a diaphragm assembly 120 of the above embodiment, the diaphragm assembly 120 is arranged on one side of the voice coil 130, and the magnetic circuit system can drive the voice coil 130 to vibrate to drive the diaphragm assembly 120 to generate sound. The sound-generating device 100 may be a speaker unit or a speaker module, etc.

[0082] like Figure 1 As shown, the sound-generating device 100 may include a housing 110, a magnetic circuit system and a vibration system, wherein the magnetic circuit system includes a permanent magnet 140, and the permanent magnet 140 is used to form a magnetic gap. The vibration system includes a diaphragm assembly 120 and a voice coil 130. The diaphragm assembly 120 and the permanent magnet 140 are both connected to the housing 110. The permanent magnet 140 is arranged on one side of the diaphragm assembly 120 along the vibration direction of the voice coil 130. One end of the voice coil 130 is connected to the diaphragm assembly 120, and the other end is located in the magnetic gap.

[0083] In this embodiment, the diaphragm assembly 120 includes a dome 122 and a diaphragm 121 of the above embodiment, and the diaphragm 121 is connected to the dome 122. By providing the dome 122 on the diaphragm 121, the strength of the diaphragm 121 can be improved and the acoustic performance of the diaphragm 121 can be optimized. The diaphragm 121 of the present invention includes an elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, and the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups, benzene rings and olefin segments. The olefin segments account for 10%-40% of the total mass of the copolymer, thereby being able to improve the loss factor of the elastomer layer to improve the damping of the diaphragm 121, thereby helping to reduce the distortion of the sound-generating device 100 using the diaphragm assembly 120 and improve the sound quality of the sound-generating device 100.

[0084] According to a fourth aspect of the present invention, an electronic device is provided. The electronic device includes the sound-generating device 100 of the above embodiment. The electronic device may be a mobile phone, a smart watch or a computer. Of course, the electronic device of the present invention also includes at least all the beneficial effects of the above embodiment, which will not be described in detail here.

[0085] The diaphragm assembly 120 of the present invention is described in detail below with specific embodiments and comparative examples. It is worth noting that the following description is merely exemplary and does not specifically limit the present invention.

[0086] Embodiment 1: The diaphragm 121 is composed of an elastomer layer composed of a polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, the molar ratio of epoxy groups to benzene rings in the elastomer layer is in the range of 5:1000, and the mass fraction of the olefin chain segment is 15%. The dome 122 is an aluminum composite material. The diaphragm 121 and the dome 122 are integrally hot-pressed, the hot-pressing temperature is 160°C, and the hot-pressing time is 20s.

[0087] Embodiment 2: The diaphragm 121 is composed of an elastomer layer composed of a polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, the molar ratio of epoxy groups to benzene rings in the elastomer layer is in the range of 5:1000, and the mass fraction of the olefin chain segment is 25%. The dome 122 is an aluminum composite material. The diaphragm 121 and the dome 122 are integrally hot-pressed, the hot-pressing temperature is 160°C, and the hot-pressing time is 20s.

[0088] Comparative Example 1: The diaphragm is composed of a layer of silicone rubber film. The dome is an aluminum composite material. The bonding layer between the diaphragm and the dome is an acrylic film. The bonding layer is annular and has a thickness of 25 μm. First, one side of the bonding layer is bonded to the dome, and then the other side of the bonding layer is pressed onto the diaphragm at room temperature for 20 seconds.

[0089] Table 1 Performance data of the diaphragm assembly of Examples 1, 2 and Comparative Example 1

[0090] Example 1 Example 2 Comparative Example 1 Diaphragm assembly thickness / μm 120 120 145 Diaphragm thickness / μm 40 40 40 Thickness of dome / um 80 80 80 Thickness of adhesive layer / μm / / 25 <![CDATA[Density g / cm 3 > 0.89 0.86 1.15 Loss Factor 0.15 0.42 0.11 25℃ ejection force / N 18.96 19.51 11.23

[0091] As shown in Table 1, the thickness of the diaphragm 121 and the dome 122 of the diaphragm assembly 120 in Examples 1 and 2 and Comparative Example 1 is the same, the thickness of the diaphragm 121 is 40 μm, and the thickness of the dome 122 is 80 μm. The overall thickness of the two diaphragm assemblies 120 in Examples 1 and 2 is 120 μm. The thickness of the adhesive layer in Comparative Example 1 is 25 μm, and the overall thickness is 145 μm. Since the diaphragm 121 of Examples 1 and 2 is integrally formed, there is no adhesive layer, which makes the thickness of the diaphragm assembly 120 of Examples 1 and 2 significantly smaller than the thickness of the diaphragm assembly of Comparative Example 1.

[0092] The density of the diaphragm 121 of Example 1 is 0.89 g / cm 3 The density of the diaphragm 121 of Example 2 is 0.86 g / cm 3 The density of the diaphragm of Comparative Example 1 is 1.15 g / cm 3 The density of the silicone rubber film is greater than the density of the elastomer layer of the present invention. Therefore, the density of the elastomer layer composed of modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer included in the diaphragm 121 in Examples 1 and 2 is relatively small, which is beneficial to the lightweight design of the diaphragm assembly 120.

[0093] The loss factor of the diaphragm 121 of Example 1 is 0.15, the loss factor of the diaphragm 121 of Example 2 is 0.42, and the loss factor of the diaphragm of Comparative Example 1 is 0.11. It can be seen that the diaphragms 121 of Examples 1 and 2 include an elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, and the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains olefin segments, thereby improving the loss factor of the elastomer layer to improve the damping of the diaphragm 121.

[0094] In addition, the olefin segments in the diaphragm 121 of Example 1 account for 15% of the total mass of the copolymer, and the olefin segments in the diaphragm 121 of Example 2 account for 25% of the total mass of the copolymer. It can be seen that since the contents of the olefin segments in the diaphragms 121 of the above two embodiments are both within the range of 10%-40%, the diaphragms 121 can have a higher loss factor.

[0095] The ejection force of the diaphragm assembly 120 of Example 1 at 25°C is 18.96N, the ejection force of the diaphragm assembly 120 of Example 2 at 25°C is 19.51N, and the ejection force of the diaphragm assembly of Comparative Example 1 at 25°C is 11.23N. It can be seen that the diaphragm 121 in Examples 1 and 2 comprises an elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, and the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups. The epoxy groups in the elastomer layer have high reactivity and can react with free radicals on the surface of the dome 122 to form chemical bonds, thereby generating a strong adhesive force, thereby making the adhesion between the diaphragm 121 and the dome 122 strong, and the epoxy groups will produce a ring-opening reaction, thereby obtaining a higher adhesive force between the diaphragm 121 and the dome 122 through intramolecular covalent bonds, so that the diaphragm assembly 120 can have a greater ejection force.

[0096] The diaphragm assemblies in Example 2 and Comparative Example 1 were assembled into the same type of sound-generating device, and the acoustic performance reliability test was performed after continuous operation for 48 hours at 3V voltage in an environment of 65°C and 95% humidity. Figure 3 As shown, they are the total harmonic distortion curves of Example 2 and Comparative Example 1, respectively. The horizontal axis represents the vibration frequency, in Hz; the vertical axis represents the total harmonic distortion, in %.

[0097] like Figure 3 As shown, between about 100 Hz and 600 Hz, the harmonic distortion of the sound-generating device 100 in Example 2 is significantly reduced, indicating that the diaphragm 121 of the example has better anti-polarization ability and better sound quality. It can be seen that the diaphragm 121 of Example 2 includes an elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, and the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains olefin segments, thereby increasing the loss factor of the elastomer layer to increase the damping of the diaphragm 121, and reducing nonlinear vibrations, thereby making the total harmonic distortion of the diaphragm assembly 120 of Example 2 lower.

[0098] In summary, the diaphragm 121 in the diaphragm assembly 120 of Example 1 and Example 2 includes an elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, and the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups, benzene rings and olefin segments. The olefin segments account for 10%-40% of the total mass of the copolymer, thereby increasing the loss factor of the elastomer layer to increase the damping of the diaphragm 121, thereby helping to reduce the distortion of the sound-generating device 100 using the diaphragm 121 and improve the sound quality of the sound-generating device 100. The benzene ring is beneficial to improving the temperature resistance and mechanical properties of the elastomer layer. The epoxy group has high reactivity and is suitable for reacting with free radicals on the surface of the ball top 122 to form chemical bonds, thereby generating stronger adhesion, thereby making the adhesion between the diaphragm 121 and the ball top 122 stronger, and the epoxy group will produce a ring-opening reaction, thereby obtaining a higher adhesion between the diaphragm 121 and the ball top 122 through intramolecular covalent bonds.

[0099] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0100] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated 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 invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A diaphragm for a sound-generating device, characterized in that: include: An elastomer layer composed of a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, wherein the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups, benzene rings and olefin segments Among them, x, y, and n are positive integers, x is 1-8, y is 1-10, the molar ratio of the epoxy group to the benzene ring is 0.05%-5%, the olefin segment accounts for 10%-40% of the total mass of the copolymer, and the loss factor of the elastomer layer between 20°C and 30°C is 0.07-2.

5.

2. The diaphragm according to claim 1, characterized in that: The olefin chain segments account for 20%-30% of the total mass of the copolymer.

3. The diaphragm according to claim 1, characterized in that: The elongation at break of the elastomer layer is 100%-800%.

4. The diaphragm according to claim 1, characterized in that: The Young's modulus of the elastomer layer is 15 MPa-700 MPa.

5. The diaphragm according to claim 1, characterized in that: The thickness of the elastomer layer is 10 μm-300 μm.

6. The diaphragm according to claim 1, characterized in that: The density of the elastomer layer is 0.7 g / cm 3 -1.0g / cm 3 ; And / or, the glass transition temperature of the elastomer layer is -50°C to -10°C.

7. The diaphragm according to claim 1, characterized in that: The modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer is formed by grafting a polystyrene-poly(ethylene-butylene)-polystyrene block copolymer with an active compound containing an epoxy group, wherein the active compound comprises at least one of glycidyl methacrylate, 1,2-epoxy-4-vinylcyclohexane and 2,3-epoxypropyltrimethylammonium chloride.

8. The diaphragm according to any one of claims 1 to 7, characterized in that: The diaphragm is formed into a single-layer structure, and the diaphragm is composed of a layer of the elastic body; Alternatively, the diaphragm is formed into a composite layer structure, the diaphragm includes the elastomer layer and a composite layer, and the composite layer includes engineering plastics and / or elastomer materials.

9. A diaphragm assembly, characterized in that: It comprises a dome and a diaphragm according to any one of claims 1 to 8, wherein the dome is connected to the diaphragm.

10. The diaphragm assembly according to claim 9, characterized in that: The diaphragm and the dome are bonded together by an adhesive layer; Alternatively, the diaphragm and the dome are integrally hot-pressed or integrally injection-molded.

11. A sound-generating device, characterized in that: The sound-generating device includes a vibration system and a magnetic circuit system coordinated with the vibration system, the vibration system includes a voice coil and a diaphragm assembly as described in claim 9 or 10, the diaphragm assembly is arranged on one side of the voice coil, and the magnetic circuit system can drive the voice coil to vibrate to drive the diaphragm assembly to produce sound.

12. An electronic device, characterized in that: Comprising the sound-generating device as claimed in claim 11.

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