Vibrating diaphragm assembly, sound production device and electronic equipment

Abstract

The invention belongs to the technical field of electroacoustics, and particularly relates to a vibrating diaphragm assembly, a sound production device and electronic equipment, the vibrating diaphragm assembly comprises a vibrating diaphragm, a globe roof and a bonding layer arranged between the vibrating diaphragm and the globe roof, the bonding layer comprises a modified polystyrene-poly (ethylene-butylene)-polystyrene block copolymer, and the modified polystyrene-poly (ethylene-butylene)-polystyrene block copolymer is arranged between the globe roof and the modified polystyrene-poly (ethylene-butylene)-polystyrene block copolymer. The modified polystyrene-poly (ethylene-butylene)-polystyrene block copolymer contains an epoxy group and a benzene ring, and the molar ratio of the epoxy group to the benzene ring is (0.05-5): 100. According to the vibrating diaphragm assembly, the bonding layer is provided with the modified polystyrene-poly (ethylene-butylene)-polystyrene block copolymer, intermolecular Van der Waals force is generated between an epoxy group and the ball top, and meanwhile, a certain degree of hydrogen bonds are also formed, so that the bonding force between the vibrating diaphragm and the top ball is enhanced, and the reliability of the vibrating diaphragm assembly is improved.

Description

Technical Field

[0001] The present invention belongs to the field of electroacoustic technology, and in particular relates to a diaphragm assembly, a sound-generating device and an electronic device. Background Art

[0002] In the existing diaphragm assembly of the sound-generating device, the diaphragm and the dome are usually fixed with an adhesive layer. There are two main ways to form the adhesive layer. The first is to form it by curing glue. Commonly used glues include silicone type, polyurethane type, epoxy resin type, acrylic type, etc. There are mainly the following problems when this type of glue is used to bond the diaphragm and the dome: the curing process is complicated due to the restrictions on transportation and storage methods; small molecular weight volatiles volatilize during curing, etc.

[0003] The second is formed by film bonding, which is easy to store and has high processing efficiency. However, since the existing diaphragms are mostly made of ethylene acrylate rubber and ethylene propylene rubber materials, the surface tension of the materials is low, and the bonding force between the diaphragm and the dome is small, resulting in low bonding strength between the diaphragm and the dome, which is prone to cracking of the diaphragm and the dome, splitting vibration, and reducing product reliability.

[0004] To this end, the present invention is proposed. Summary of the invention

[0005] The main purpose of the present invention is to provide a diaphragm assembly, a sound-generating device and an electronic device. The adhesive layer in the diaphragm assembly of the present invention has a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, in which the epoxy groups and the ball top produce intermolecular van der Waals forces and also form a certain degree of hydrogen bonds, thereby enhancing the adhesion between the diaphragm and the top ball and improving the reliability of the diaphragm assembly.

[0006] In order to achieve the above objectives, the present invention provides the following technical solutions.

[0007] In a first aspect of the present invention, a diaphragm assembly is provided, comprising a diaphragm, a dome, and an adhesive layer disposed between the diaphragm and the dome, wherein the adhesive layer comprises a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, wherein the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups and benzene rings, and the molar ratio of the epoxy groups to the benzene rings is (0.05-5):100.

[0008] In some embodiments of the present invention, in the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, the molar ratio of the epoxy group to the benzene ring is (0.1-1):100.

[0009] In some embodiments of the present invention, at 25° C., the ejection force per unit area of ​​the diaphragm assembly is 4N to 30N.

[0010] In some embodiments of the present invention, after baking at 130° C. for 6 hours, the loss rate of the ejection force per unit area of ​​the diaphragm assembly compared to the ejection force at 25° C. is -15% to 3%.

[0011] In some embodiments of the present invention, after baking at 95% humidity and 65° C. for 48 hours, the loss rate of the ejection force of the diaphragm assembly per unit area compared to the ejection force at 25° C. is -10% to 5%.

[0012] In some embodiments of the present invention, the thickness of the adhesive layer is 10 μm to 100 μm.

[0013] In some embodiments of the present invention, at 25° C., the elastic modulus of the adhesive layer is 10 MPa to 800 MPa.

[0014] In some embodiments of the present invention, the thickness of the diaphragm assembly is 60 μm to 300 μm.

[0015] In some embodiments of the present invention, at 25°C, the glass transition temperature of the adhesive layer is -50°C to -5°C.

[0016] In some embodiments of the present invention, at 25°C, the glass transition temperature of the adhesive layer is -30°C to -15°C.

[0017] In some embodiments of the present invention, the diaphragm and the dome are bonded together through the bonding layer at a bonding temperature of 100° C. to 200° C. and a bonding time of 5 s to 60 s.

[0018] In some embodiments of the present invention, the bonding temperature of the diaphragm and the dome through the bonding layer is 150° C. to 180° C.

[0019] In some embodiments of the present invention, the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer is obtained by grafting a polystyrene-poly(ethylene-butylene)-polystyrene block copolymer with an epoxy compound.

[0020] In some embodiments of the present invention, the epoxy compound is selected from at least one of glycidyl methacrylate, 1,2-epoxy-4-vinylcyclohexane, and 2,3-epoxypropyltrimethylammonium chloride.

[0021] In some embodiments of the present invention, the material of the diaphragm is selected from at least one of engineering plastics and elastomeric materials; and / or the material of the dome is selected from at least one of carbon fiber, aluminum metal, aluminum-based composite materials and engineering plastics.

[0022] A second aspect of the present invention provides a sound-generating device, wherein the sound-generating device comprises the diaphragm assembly described in the first aspect.

[0023] According to a third aspect of the present invention, an electronic device is provided, wherein the electronic device comprises the sound-generating device according to the second aspect.

[0024] Compared with the prior art, the present invention achieves the following technical effects:

[0025] The adhesive layer of the present invention has a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, in which the epoxy groups and the ball top generate intermolecular van der Waals forces and also form a certain degree of hydrogen bonds, thereby enhancing the adhesion between the diaphragm and the top ball and improving the reliability of the diaphragm assembly.

[0026] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0028] Figure 1 is a cross-sectional view of a diaphragm assembly according to some embodiments of the present invention;

[0029] Figure 2 is a cross-sectional view of a sound-generating device according to some embodiments of the present invention;

[0030] Figure 3 Schematic diagram of THD curves of the speakers corresponding to the diaphragm assemblies in Example 1 and Comparative Examples 1-2.

[0031] Reference numerals

[0032] 100, diaphragm assembly;

[0033] 110, diaphragm; 120, dome; 130, bonding layer;

[0034] 200. Sound-generating device;

[0035] 210, housing; 220, magnetic circuit system; 230, voice coil. DETAILED DESCRIPTION

[0036] The exemplary embodiments of the present invention will be described in more detail below with reference to specific embodiments. It should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the specification and claims of the present invention and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0038] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0039] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0040] In the description of the embodiments of the present invention, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0041] In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0042] In the description of the embodiments of the present invention, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention.

[0043] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0044] Currently, the bonding force between the existing diaphragm and the dome is relatively small, resulting in low bonding strength between the two, which can easily cause the diaphragm and the dome to crack and split vibration, reducing product reliability.

[0045] To this end, the present invention provides a diaphragm assembly, such as Figure 1 As shown, the diaphragm assembly 100 includes a diaphragm 110, a dome 120, and an adhesive layer 130 disposed between the diaphragm 110 and the dome 120, the adhesive layer 130 includes a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, wherein the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups and benzene rings, and the molar ratio of epoxy groups to benzene rings is (0.05-5):100.

[0046] In the present invention, the diaphragm 110 and the dome 120 are bonded by the bonding layer 130. The bonding layer 130 contains a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, wherein the epoxy groups and the dome generate intermolecular van der Waals forces, and also form a certain degree of hydrogen bonds. At the bonding temperature, the epoxy groups will produce a "ring opening" reaction, thereby obtaining a higher bonding force through intramolecular covalent bonds. In an embodiment of the present invention, the molar ratio of epoxy groups to benzene rings is (0.05-5):100. When the content of epoxy groups is low, the bonding force between the diaphragm 110 and the dome 120 is low, and when the content of epoxy groups is high, the required bonding temperature is high, resulting in reduced preparation efficiency. Illustratively, in the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, the molar ratio of epoxy groups to benzene rings can be one of 0.05:100, 0.06:100, 0.07:100, 0.08:100, 0.09:100, 0.1:100, 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100, 2:100, 3:100, 4:100, 5:100 or any value satisfying the above range.

[0047] In some embodiments of the present invention, the molar ratio of epoxy groups to benzene rings in the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer is (0.1-1): 100. Thus, better adhesion between the diaphragm 110 and the dome 120 is further achieved, and the preparation efficiency is high.

[0048] In an embodiment of the present invention, the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer is obtained by grafting polystyrene-poly(ethylene-butylene)-polystyrene block copolymer (SEBS) with an epoxy compound. In some embodiments of the present invention, the epoxy compound is selected from at least one of glycidyl methacrylate, 1,2-epoxy-4-vinylcyclohexane, and 2,3-epoxypropyltrimethylammonium chloride. This achieves a better bonding strength between the diaphragm and the dome, and improves the reliability of the diaphragm assembly.

[0049] In the present invention, SEBS grafting is a free radical reaction, in which monomers and oligomers are grafted onto the SEBS molecular chain, and the grafting position is on the unhydrogenated double bonds. Taking the grafting reaction of SEBS and glycidyl methacrylate as an example, the grafting reaction principle is shown in the following formula (1).

[0050]

[0051] In some embodiments of the present invention, the material of the diaphragm is selected from at least one of engineering plastics and elastomeric materials. For example, the material of the diaphragm can be a composite of one or more materials selected from polyetheretherketone (PEEK), polyimide (PI), thermoplastic polyurethane elastomer rubber (TPU), thermoplastic polyester elastomer (TPEE), rubber, etc.

[0052] In some embodiments of the present invention, the material of the dome is selected from at least one of carbon fiber, aluminum metal, aluminum-based composite materials and engineering plastics. For example, the material of the dome can be one of carbon fiber, aluminum metal, aluminum-based composite materials, polyetheretherketone (PEEK), and polyimide (PI).

[0053] In an embodiment of the present invention, the diaphragm 110 and the dome 120 are bonded by an adhesive layer 130, and the ejection force per unit area of ​​the diaphragm assembly 100 represents the magnitude of the bonding force between the diaphragm 110 and the dome 120. Since the adhesive layer 130 has a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, the diaphragm assembly 100 has a strong bonding force at room temperature and a high bonding strength. In an embodiment of the present invention, at 25°C, the ejection force per unit area of ​​the diaphragm assembly 100 is 4N to 30N. When the ejection force is less than 4N, the bonding force is small, the product reliability is low, and it cannot meet the actual product usage requirements. Illustratively, at 25°C, the ejection force per unit area of ​​the diaphragm assembly 100 can be one of 4N, 5N, 6N, 7N, 8N, 9N, 10N, 11N, 12N, 13N, 14N, 15N, 16N, 17N, 18N, 19N, 20N, 21N, 22N, 23N, 24N, 25N, 26N, 27N, 28N, 29N, 30N or any value that satisfies the above range.

[0054] In some embodiments of the present invention, at 25° C., the ejection force per unit area of ​​the diaphragm assembly 100 is 10 N to 30 N. This further achieves better bonding strength and improves reliability.

[0055] In the embodiment of the present invention, since the adhesive layer 130 contains epoxy groups, under certain high temperature treatment, the epoxy groups will produce a "ring-opening" reaction, thereby obtaining a higher bonding force through intramolecular covalent bonds. Therefore, under high temperatures, such as 130°C, the ejection force per unit area of ​​the diaphragm assembly 100 is almost not lost. For example, when the bonding time is short, the adhesion between the diaphragm 110 and the ball top 120 increases under high temperature conditions. In the embodiment of the present invention, after baking at 130°C for 6 hours, the ejection force per unit area of ​​the diaphragm assembly 100 is lost at a rate of -15% to 3% compared to the ejection force at 25°C. Exemplarily, the loss rate can be one of -15%, -14%, -13%, -12%, -11%, -10%, -9%, -8%, -7%, -6%, -5%, -4%, -3%, -2%, -1%, 0%, 1%, 2%, 3% or any value that meets the above range.

[0056] In an embodiment of the present invention, after baking at 95% humidity and 65° C. for 48 hours, the loss rate of the ejection force per unit area of ​​the diaphragm assembly 100 compared to the ejection force at 25° C. is -10% to 5%. Exemplarily, the loss rate may be -10%, -9%, -8%, -7%, -6%, -5%, -4%, -3%, -2%, -1%, 0%, 1%, 2%, 3%, 4%, 5%, or any value satisfying the above range.

[0057] The thickness of the adhesive layer 130 in the present invention needs to be appropriate. In an embodiment of the present invention, the thickness of the adhesive layer 130 is 10μm to 100μm. If the thickness of the adhesive layer 130 is greater than 100μm, the vibration space of the sound-generating device such as a speaker is reduced, and the maximum amplitude that can be achieved is reduced, thereby affecting the sound effect; and if the thickness of the adhesive layer 130 is less than 10μm, the ejection force of the diaphragm assembly 100 is low, resulting in reduced reliability and efficiency of the speaker, which cannot meet the use requirements. Exemplarily, the thickness of the adhesive layer 130 can be one of 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, or any value that meets the above range value.

[0058] In some embodiments of the present invention, the thickness of the adhesive layer 130 may be 20 μm to 40 μm, thereby further improving the adhesive strength and reliability.

[0059] In an embodiment of the present invention, the thickness of the diaphragm assembly 100 is 60 μm to 300 μm. For example, the thickness of the diaphragm assembly 100 can be 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 280 μm, 290 μm, 300 μm or any value satisfying the above range.

[0060] The elastic modulus of the adhesive layer in the present invention refers to the ability to resist deformation when deformed by force. When the elastic modulus of the adhesive layer is low, the adhesive layer body may crack when the sound-emitting device such as a speaker works for a long time; and when the elastic modulus of the adhesive layer is high, it may cause greater stress and stress concentration during the speaker production process, especially when excessive pressure is applied, which may cause the diaphragm to deform or rupture. In an embodiment of the present invention, at 25°C, the elastic modulus of the adhesive layer 130 is 10MPa to 800MPa, for example, 20MPa to 100MPa. Exemplarily, the elastic modulus of the adhesive layer 130 can be one of 10MPa, 20MPa, 30MPa, 40MPa, 50MPa, 60MPa, 70MPa, 80MPa, 90MPa, 100MPa, 150MPa, 200MPa, 250MPa, 300MPa, 350MPa, 400MPa, 450MPa, 500MPa, 550MPa, 600MPa, 650MPa, 700MPa, 750MPa, 800MPa, or any value within the above range.

[0061] The glass transition temperature (Tg) is the temperature at which a material changes from a glassy state to a highly elastic state. In the present invention, when the glass transition temperature of the adhesive layer 130 is low, at a relatively low temperature, the adhesive layer 130 will become too hard and brittle, and the elastic modulus will rise rapidly, resulting in excessive rigidity of the material, a significant increase in the product F0, and a decrease in the toughness of the diaphragm 110, which is prone to the risk of film cracking. In order to ensure that the adhesive layer 130 can still maintain the stability and reliability of physical properties in a low temperature environment and meet the requirements of use, the glass transition temperature needs to be lower than -5°C. In an embodiment of the present invention, at 25°C, the glass transition temperature of the adhesive layer 130 is -50°C to -5°C, for example, -30°C to -15°C, thereby achieving better bonding strength between the diaphragm 110 and the dome 120 and improving the reliability of the diaphragm assembly 100. For example, the glass transition temperature of the adhesive layer 130 may be one of -50°C, -40°C, -30°C, -20°C, -10°C, -5°C, or any value within the above range.

[0062] The bonding temperature when the diaphragm 110 and the dome 120 are bonded directly affects the bonding efficiency of the bonding layer 130. Specifically, at a relatively low temperature, the bonding layer 130 has a relatively high viscosity and poor fluidity, and cannot fully penetrate into the gaps of the bonded objects, resulting in a slow bonding speed and poor bonding effect; when the bonding temperature is too high, the bonding layer 130 will undergo thermal decomposition, and will also damage the diaphragm 110, affecting the flatness of the diaphragm 110. In an embodiment of the present invention, the bonding temperature of the diaphragm 110 and the dome 120 bonded through the bonding layer 130 is 100°C to 200°C, and the bonding time is 5s to 60s, thereby achieving better bonding strength and bonding efficiency.

[0063] In an embodiment of the present invention, the bonding temperature of the diaphragm 110 and the dome 120 through the bonding layer 130 can be 150°C to 180°C. This further achieves better bonding strength and bonding efficiency. Exemplarily, the bonding temperature can be one of 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, or any value that satisfies the above range. The bonding time can be one of 5s, 6s, 7s, 8s, 9s, 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s, 60s, or any value that satisfies the above range.

[0064] The present invention also provides a sound-generating device, which includes a diaphragm assembly according to any of the above embodiments. Since the diaphragm assembly in the present invention has the advantage of high reliability, it can improve the sound quality of the sound-generating device, thereby improving the overall stability and sound-generating effect of the sound-generating device.

[0065] The diaphragm assembly provided by the present invention can be used to form a sound-generating device of any structure, such as the following typical sound-generating devices: Figure 2 As shown, the sound-generating device 200 may be a speaker, which includes a housing 210, a vibration system disposed in the housing 210, and a magnetic circuit system 220 matched with the vibration system, wherein the vibration system includes a diaphragm assembly 100 and a voice coil 230 coupled to one side of the diaphragm assembly 100. When the sound-generating device 200 is working, after the voice coil 230 is energized, under the action of the magnetic field force of the magnetic circuit system 220, the voice coil 230 may vibrate up and down to drive the diaphragm assembly 100 to generate sound.

[0066] The present invention also provides an electronic device having a sound-generating device according to any of the above embodiments. The electronic device has a sound-generating device 200, thereby achieving the advantages of high stability and reliability of the electronic device and improved sound-generating effect. Optionally, the electronic device can be a mobile phone, a PAD, a laptop computer, a television, or a smart wearable device.

[0067] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the amounts of the experimental reagents, unless otherwise specified, are the amounts of reagents used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0068] The following describes the diaphragm assembly and the sound-generating device of the present invention in detail with specific embodiments and comparative examples. It is worth noting that the following description is only exemplary and does not specifically limit the present invention. Moreover, the comparative examples are selected to reflect the technical progress of the main technical points of the present invention by comparison with the embodiments, and the comparative examples are not all prior art in the field.

[0069] Example 1

[0070] A diaphragm assembly is disclosed, see Figure 1 As shown, the diaphragm assembly 100 includes a diaphragm 110, a dome 120, and an adhesive layer 130 disposed between the diaphragm 110 and the dome 120, and the adhesive layer 130 is an annular structure with a thickness of 30 μm. The diaphragm 110 is made of ethylene acrylate rubber, the dome 120 is made of aluminum composite material, and the adhesive layer 130 is an epoxy group-modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer (SEBS) obtained by grafting with glycidyl methacrylate, and the molar ratio of epoxy group to benzene ring is 0.1:100.

[0071] The process of bonding the diaphragm 110 and the dome 120 via the bonding layer 130 is as follows: firstly bonding one side of the bonding layer 130 to the dome 120 , and then hot pressing the other side of the bonding layer 130 to the diaphragm 110 at 180° C. for 20 seconds.

[0072] Example 2

[0073] The remaining operations were the same as those in Example 1, except that the molar ratio of epoxy group to benzene ring was 0.05:100.

[0074] Example 3

[0075] The remaining operations are the same as those in Example 1, except that the thickness of the bonding layer is 45 μm.

[0076] Example 4

[0077] The remaining operations are the same as those in Example 1, except that the bonding temperature is 160° C. and the bonding time is 30 seconds.

[0078] Comparative Example 1

[0079] The remaining operations are the same as in Example 1, except that:

[0080] The material of the diaphragm 110 is ethylene acrylate rubber, the material of the dome 120 is an aluminum composite material, and the adhesive layer 130 is made of polyacrylate pressure-sensitive adhesive.

[0081] Comparative Example 2

[0082] The remaining operations are the same as in Example 1, except that:

[0083] The material of the diaphragm 110 is ethylene acrylate rubber, the material of the dome 120 is an aluminum composite material, and the adhesive layer 130 is made of UV curing glue.

[0084] Ejection force test.

[0085] Ejection force test method:

[0086] a) Use tooling to fix the diaphragm assembly;

[0087] b) Install the top head under the dynamometer, and place the diaphragm assembly and the top head of the dynamometer vertically;

[0088] c) Run the dynamometer with the ejector head in vertical contact with the ball top until the diaphragm separates from the ball top or the diaphragm is damaged. Record the force value of the dynamometer, which is the ejection force value.

[0089] The calculation method of the ejection force loss rate in the present invention is as follows:

[0090] ((the ejection force per unit area of ​​the diaphragm assembly at 25°C - the ejection force per unit area of ​​the diaphragm assembly after baking at 130°C for 6 hours or the ejection force per unit area of ​​the diaphragm assembly after baking at 95% humidity and 65°C for 48 hours) / the ejection force per unit area of ​​the diaphragm assembly at 25°C) * 100%.

[0091] Modulus of elasticity.

[0092] Elastic modulus test method: refer to standard GB / T 33061.10-2016 and use rheometer for testing.

[0093] The rheometer can record the stress changes under different strains to obtain a stress-strain curve. There is usually a linear part on the stress-strain curve, which is the linear elastic region of the material. The elastic modulus of the bonding layer can be obtained through this linear part.

[0094] Glass transition temperature.

[0095] Test method: DSC (differential scanning calorimetry) was used for testing.

[0096] The test results are shown in Table 1.

[0097] Table 1 Summary of test data of adhesive layer in Example 1 and Comparative Example 1

[0098]

[0099] It can be found from Table 1 that under the conditions of the same bonding area and the same bonding thickness, the bonding effect of the diaphragm assembly in the embodiment is better than that of the diaphragm assembly in the comparative example, and the diaphragm assembly in the embodiment has strong reliability. Specifically, the bonding layer of Example 1 is a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer containing epoxy groups, and has the largest ejection force. The bonding force of the bonding layer tested at 130°C / 6h increased by 10%, and the bonding force of the bonding layer tested at 95% humidity / 65°C / 48h increased by 6%. In other words, in Example 1, the ejection force loss rate of the adhesive layer after 130°C / 6h is -10%, and the ejection force loss rate after 95% humidity / 65°C / 48h is -6%; in Example 2, the ejection force loss rate of the adhesive layer after 130°C / 6h is -7%, and the ejection force loss rate after 95% humidity / 65°C / 48h is 0.6%; in Example 3, the ejection force loss rate of the adhesive layer after 130°C / 6h is -7%, and the ejection force loss rate after 95% humidity / 65°C / 48h is -5%; in Example 4, the ejection force loss rate of the adhesive layer after 130°C / 6h is -11%, and the ejection force loss rate after 95% humidity / 65°C / 48h is -5%; while in Comparative Example 1, the ejection force loss rate of the adhesive layer after 95% humidity / 65°C / 48h is 20%, and the ejection force loss rate of the adhesive layer after 130°C / 6h in Comparative Example 2 is 27%. At the same time, the elastic modulus of the adhesive layer in the present invention is much higher than that in Comparative Examples 1 and 2. Under certain temperature and pressure, the adhesive layer in the embodiment of the present invention contains epoxy groups, which can generate intermolecular van der Waals forces with the diaphragm and the dome, and also form a certain degree of hydrogen bonding force. Under higher temperature and pressure, the epoxy groups will produce a "ring opening" reaction, thereby obtaining higher bonding strength through intramolecular covalent bonds.

[0100] Acoustic performance test comparison

[0101] In the present invention, the diaphragm assemblies obtained in Example 1 and Comparative Examples 1-2 are respectively assembled into micro-speakers of the same structure and model to perform acoustic performance tests on the products.

[0102] like Figure 3As shown in the figure, the total harmonic distortion curves of the speakers corresponding to Example 1 and Comparative Examples 1-2 show that distortion occurs in Comparative Example 1, but there is no problem in Example 1 and Comparative Example 2. After disassembling the product, it is found that the adhesive layer in Comparative Example 1 cracks, and there is a slight crack in Comparative Example 2, while there is no crack in Example 1. This proves again that the adhesive layer containing epoxy groups in Example 1 obtains higher bonding strength through intramolecular covalent bonds.

[0103] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A diaphragm assembly, characterized in that: The invention comprises a diaphragm, a dome and an adhesive layer disposed between the diaphragm and the dome, wherein the adhesive layer comprises a modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, wherein: The modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer contains epoxy groups and benzene rings, and the molar ratio of the epoxy groups to the benzene rings is (0.05-5):

100.

2. The diaphragm assembly according to claim 1, characterized in that: In the modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer, the molar ratio of the epoxy group to the benzene ring is (0.1-1):

100.

3. The diaphragm assembly according to claim 1 or 2, characterized in that: At 25°C, the ejection force per unit area of ​​the diaphragm assembly is 4N to 30N; Preferably, after baking at 130° C. for 6 hours, the loss rate of the ejection force per unit area of ​​the diaphragm assembly is -15% to 3% compared with the ejection force at 25° C.; Preferably, after baking at 95% humidity and 65° C. for 48 hours, the loss rate of the ejection force per unit area of ​​the diaphragm assembly compared to the ejection force at 25° C. is -10% to 5%.

4. The diaphragm assembly according to claim 1 or 2, characterized in that: The thickness of the adhesive layer is 10 μm to 100 μm; Preferably, at 25°C, the elastic modulus of the adhesive layer is 10MPa to 800MPa; Preferably, the thickness of the diaphragm assembly is 60 μm to 300 μm.

5. The diaphragm assembly according to claim 1 or 2, characterized in that: At 25°C, the glass transition temperature of the adhesive layer is -50°C to -5°C; Preferably, at 25°C, the glass transition temperature of the adhesive layer is -30°C to -15°C.

6. The diaphragm assembly according to claim 1 or 2, characterized in that: The bonding temperature of the diaphragm and the dome through the bonding layer is 100° C. to 200° C., and the bonding time is 5s to 60s; Preferably, the bonding temperature of the diaphragm and the dome through the bonding layer is 150° C. to 180° C.

7. The diaphragm assembly according to claim 1 or 2, characterized in that: The modified polystyrene-poly(ethylene-butylene)-polystyrene block copolymer is obtained by grafting a polystyrene-poly(ethylene-butylene)-polystyrene block copolymer with an epoxy compound; Preferably, the epoxy compound is selected from at least one of glycidyl methacrylate, 1,2-epoxy-4-vinylcyclohexane, and 2,3-epoxypropyltrimethylammonium chloride.

8. The diaphragm assembly according to claim 1, characterized in that: The material of the diaphragm is selected from at least one of engineering plastics and elastomeric materials; and / or, The material of the dome is selected from at least one of carbon fiber, aluminum metal, aluminum-based composite materials and engineering plastics.

9. A sound-generating device, characterized in that: Comprising the diaphragm assembly described in any one of claims 1-8.

10. An electronic device, characterized in that: Includes the sound-generating device as claimed in claim 9.

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