Loudspeaker diaphragm, sound production device and electronic equipment

Abstract

The utility model discloses a loudspeaker diaphragm, a sounding device and electronic equipment. The loudspeaker diaphragm comprises an ethylene-acrylate rubber film layer and a thermoplastic polyurethane elastomer film layer which are laminated, wherein the glass transition point of the ethylene-acrylate rubber film layer is-20 DEG C to-60 DEG C, and the melting point of the thermoplastic polyurethane elastomer film layer is greater than or equal to 170 DEG C. The loudspeaker diaphragm provided by the utility model can reduce the stress loss ratio of the diaphragm after being fixed and stretched while giving consideration to both low modulus and high damping; therefore, the sound production device adopting the loudspeaker diaphragm can be ensured to have good sound quality.

Description

Technical Field

[0001] The utility model relates to the technical field of acoustics, and more specifically, to a loudspeaker diaphragm, a sound-generating device and an electronic device. Background Art

[0002] In the related art, the diaphragm of speakers, especially micro speakers, is usually made of rubber material. When micro speakers are used in electronic products with high-strength waterproof requirements, the current rubber diaphragm suffers from large stress loss under long-term fixed stretching, resulting in the diaphragm being unable to return to a balanced position, causing a decline in sound quality and failing to meet the user's listening needs.

[0003] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Utility Model Content

[0004] One purpose of the utility model is to provide a new technical solution for a loudspeaker diaphragm.

[0005] According to a first aspect of the utility model, a loudspeaker diaphragm is provided. The loudspeaker diaphragm comprises: an ethylene-acrylate rubber film layer and a thermoplastic polyurethane elastomer film layer which are stacked;

[0006] The glass transition point of the ethylene-acrylate rubber film layer is -20°C to -60°C, and the melting point of the thermoplastic polyurethane elastomer film layer is greater than or equal to 170°C.

[0007] Optionally, a stress retention rate of the loudspeaker diaphragm during stress relaxation is greater than or equal to 54%.

[0008] Optionally, the room temperature damping factor of the loudspeaker diaphragm is greater than or equal to 0.12; and / or the room temperature storage modulus of the loudspeaker diaphragm is 2 MPa to 100 MPa.

[0009] Optionally, the thickness of the loudspeaker diaphragm is 20 μm to 150 μm; and / or the thickness of the thermoplastic polyurethane elastomer film layer in the loudspeaker diaphragm accounts for 20% to 60%.

[0010] Optionally, the density of the speaker diaphragm is 1.1 g / cm 3 Up to 1.5g / cm 3 .

[0011] Optionally, the loudspeaker diaphragm includes a layer of the ethylene-acrylate rubber film layer and a layer of the thermoplastic polyester elastomer film layer, and the ethylene-acrylate rubber film layer is bonded to one side of the thermoplastic polyester elastomer film layer.

[0012] Optionally, the loudspeaker diaphragm includes one layer of the ethylene-acrylate rubber film layer and two layers of the thermoplastic polyester elastomer film layers, and the ethylene-acrylate rubber film layer is located between the two layers of the thermoplastic polyester elastomer film layers.

[0013] Optionally, the loudspeaker diaphragm comprises two layers of the ethylene-acrylate rubber film layers and one layer of the thermoplastic polyester elastomer film layer, and the thermoplastic polyester elastomer film layer is located between the two layers of the ethylene-acrylate rubber film layers.

[0014] According to a second aspect of the utility model, a sound-generating device is provided, which includes the loudspeaker diaphragm of the above embodiment.

[0015] According to a third aspect of the present invention, an electronic device is provided, which includes the sound generating device of the above embodiment.

[0016] A technical effect of the present application is that the speaker diaphragm includes a stacked ethylene-acrylate rubber film layer and a thermoplastic polyurethane elastomer film layer, and the glass transition point of the ethylene-acrylate rubber film layer is -20°C to -60°C. The speaker diaphragm of the utility model has both low modulus and high damping. Since the damping of the thermoplastic polyurethane elastomer film layer is lower than that of the ethylene-acrylate rubber film layer, the friction loss between the molecular chains of the speaker diaphragm during the stretching process is reduced, and the stress loss ratio after fixed stretching is also reduced, thereby ensuring that the sound-generating device using the speaker diaphragm can have good sound quality.

[0017] Other 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 accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0019] Figure 1 It is a structural schematic diagram of a sound-generating device according to an embodiment of the utility model.

[0020] Figure 2 It is a structural schematic diagram of a loudspeaker diaphragm according to an embodiment of the utility model.

[0021] Figure 3 It is a structural schematic diagram of a loudspeaker diaphragm according to another embodiment of the utility model.

[0022] Figure 4 It is a structural schematic diagram of a loudspeaker diaphragm according to another embodiment of the utility model.

[0023] Figure 5 It is a harmonic distortion curve of a sound-generating device using a loudspeaker diaphragm according to an embodiment of the utility model.

[0024] Figure 6 It is the harmonic distortion curve of the sound-generating device using the AEM rubber diaphragm.

[0025] Reference numerals:

[0026] 100, sound-generating device; 10, housing; 20, speaker diaphragm; 30, voice coil; 40, permanent magnet;

[0027] 21. Ethylene-acrylate rubber film layer; 22. Thermoplastic polyurethane elastomer film layer. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present invention 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 invention.

[0029] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] According to an embodiment of the present application, a speaker diaphragm 20 is provided. Figures 1 to 4 As shown, the speaker diaphragm 20 includes a stacked ethylene-acrylate rubber film layer and a thermoplastic polyurethane elastomer film layer 22; wherein the glass transition point of the ethylene-acrylate rubber film layer 21 is -20°C to -60°C, and the melting point of the thermoplastic polyurethane elastomer film layer 22 is greater than or equal to 170°C.

[0034] In this embodiment, the speaker diaphragm 20 of the utility model includes a stacked ethylene-acrylate rubber film layer 21 and a thermoplastic polyurethane elastomer film layer 22, so that the speaker diaphragm 20 has both low modulus and high damping. Since the damping of the thermoplastic polyurethane elastomer film layer 22 is lower than that of the ethylene-acrylate rubber film layer 21, the friction loss between the molecular chains of the speaker diaphragm 20 during the stretching process is reduced, and the stress loss ratio after fixed stretching is also reduced, thereby ensuring that the sound-generating device 100 using the speaker diaphragm 20 can have good sound quality. For example, in a high water pressure use environment, the speaker diaphragm 20 can be stretched by the water pressure and deformed. The stress loss of the speaker diaphragm 20 of the utility model is relatively low, for example, it can be reduced to less than 47%. When the external force is withdrawn, the speaker diaphragm 20 can rebound, so that the speaker diaphragm 20 can rebound to a balanced position, thereby ensuring that the sound quality of the sound-generating device is good. In addition, the speaker diaphragm 20 of the utility model can also be used in a high pressure environment.

[0035] In this embodiment, the glass transition point of the ethylene-acrylate rubber film layer 21 is -20°C to -60°C. The glass transition point, i.e., the glass transition temperature (Tg), refers to the temperature at which a material, such as a polymer material, transitions from a glass state to a highly elastic state. That is, when the temperature is higher than the glass transition point, for example, the ethylene-acrylate rubber film layer 21 is in a highly elastic state. In the highly elastic state, the ethylene-acrylate rubber film layer 21 has high elasticity. When the temperature is lower than the glass transition temperature, the ethylene-acrylate rubber film layer 21 is in a glass state. In the glass state, the ethylene-acrylate rubber film layer 21 has low elasticity and high hardness.

[0036] The glass transition point of the ethylene-acrylate rubber film layer 21 is -20°C to -60°C, which enables the ethylene-acrylate rubber film layer 21 to be in a highly elastic state at normal use temperature (eg, -10°C to 10°C), thereby making the speaker diaphragm 20 more elastic.

[0037] For example, the above-mentioned test method for the glass transition point can be tested according to the ASTM D882 standard. Specifically, a tensile testing machine is used to test the material. A material sample of a set size is clamped with the clamp of the tensile testing machine. The temperature of the test environment is 23±10°C and the relative humidity is 50±5%. During the test, the heating rate is 3°C / min, and the strain of the material is 0.2%. The temperature corresponding to the peak value of the loss factor of the material is selected as the glass transition point. Of course, the test method for the glass transition point is not limited to the above-mentioned embodiment, and those skilled in the art can set it according to actual needs.

[0038] In this embodiment, the thermoplastic polyurethane elastomer film layer 22 is formed by polymerizing diphenylmethane diisocyanate and / or 1,5-naphthalene diisocyanate and polycarbonate diol. The thermoplastic polyurethane elastomer film layer 22 has good flexibility, high and low temperature resistance and vibration stability. For example, the thermoplastic polyurethane elastomer film layer 22 is processed from a high temperature resistant polyurethane material polymerized from diphenylmethane diisocyanate and polycarbonate diol. Alternatively, the thermoplastic polyurethane elastomer film layer 22 can also be processed from a high temperature resistant polyurethane material polymerized from 1,5-naphthalene diisocyanate and polycarbonate diol. Those skilled in the art can determine according to actual conditions, and no specific limitation is made here.

[0039] The speaker diaphragm 20 is a composite of an ethylene-acrylate rubber film layer 21 and a thermoplastic polyurethane elastomer film layer 22, and has an excellent elastic recovery rate while taking into account low modulus and high damping. At the same F0 (for example, F0 refers to the lowest vibration frequency of the speaker diaphragm 20 that can make sound), the thickness of the speaker diaphragm 20 of the utility model is relatively small. For example, the thickness of the speaker diaphragm 20 of the utility model can be reduced by 30% compared with the speaker diaphragm 20 that only uses ethylene-acrylate rubber as the speaker diaphragm 20, and thus the mass of the speaker diaphragm 20 can be reduced by 30%. And the speaker using the speaker diaphragm 20 can have a higher mid-frequency loudness.

[0040] In this embodiment, the melting point of the thermoplastic polyurethane elastomer film layer 22 is greater than or equal to 170° C. The melting point of the thermoplastic polyurethane elastomer film layer 22 is relatively high, so that the thermoplastic polyurethane elastomer film layer 22 has high temperature resistance, which is beneficial to improving the high temperature resistance of the speaker diaphragm 20 and preventing the speaker diaphragm 20 from melting in a high temperature environment.

[0041] Preferably, the ethylene-acrylate rubber is a ternary structure, and the molecular formula is:

[0042] Wherein, x, y, z are natural numbers, R and R' are alkyl groups, and the specific values ​​of x, y, z and the specific structures of R, R' are not limited herein.

[0043] Optionally, x is 1, 2, 3, 4, 5, 6, 7, 8, 9, etc. y is 1, 2, 3, 4, 5, 6, 7, 8, 9, etc. z is 1, 2, 3, 4, 5, 6, 7, 8, 9, etc. R and R' are methyl, ethyl, propyl, butyl, etc.

[0044] In this embodiment, the ethylene-acrylate rubber includes a third unit containing a carboxyl group in addition to the above-mentioned main raw materials, and in the third unit, the carboxyl group is bonded to the R group. In this molecular formula, the R group is bonded to the ethylene with double bonds opened and the methyl acrylate with double bonds opened to form a chain segment. Since the raw materials of the third unit contain carboxyl groups, the ethylene-acrylate rubber can be cross-linked by an amine cross-linking agent in the air at room temperature, and can be formed by air pressure. When the carboxylic acid group is not included, the molding of the ethylene-acrylate rubber adopts a peroxide cross-linking agent. The cross-linking reaction of the peroxide cross-linking agent needs to be carried out under high temperature and high pressure. Compared with the process of preparing ethylene-acrylate rubber using a peroxide cross-linking agent, this method of the utility model makes the preparation of ethylene-acrylate rubber easy.

[0045] Optionally, the ethylene-acrylate rubber uses an amine crosslinking agent, and the amine crosslinking agent includes at least one of hexamethylenediamine, hexamethylenediamine salt, hexamethylenediamine carbamate, triethylenetetramine, 2,2'-methylenedianiline and di-o-tolylguanidine, all of which can crosslink the raw materials of the ethylene-acrylate rubber. The ethylene-acrylate rubber film layer 21 has the characteristics of high and low temperature resistance, oil resistance, and excellent mechanical properties.

[0046] Of course, in other examples, the ethylene-acrylate rubber may not contain the third unit.

[0047] In one embodiment, the stress retention rate of the loudspeaker diaphragm 20 during the stress relaxation process is greater than or equal to 54%.

[0048] The stress retention rate during stress relaxation is the ratio of the minimum value to the maximum value of the material stress during stress relaxation. The test method of stress retention rate can be carried out according to ASTM D5026-15 standard. For example, the speaker diaphragm 20 is kept warm under the condition of an ambient temperature of 23°C. The warm-keeping time is 5 minutes. Then, the speaker diaphragm 20 is instantly stretched to a strain of 10% using a tensile testing machine. Next, the speaker diaphragm 20 is relaxed for 10 minutes and recovered for 5 minutes to obtain a stress-strain curve. The maximum stress and the minimum stress on the stress-strain curve are taken for calculation to obtain the stress retention rate.

[0049] In a high water pressure environment, the speaker diaphragm 20 can be stretched by the water pressure and deformed. After being used for a period of time in a high water pressure environment, the molecular chain of the speaker diaphragm 20 will cause stress loss due to internal friction. If the stress retention rate is less than 54%, the stress loss of the speaker diaphragm 20 will be too large. When the external force is withdrawn, the speaker diaphragm 20 will not be able to rebound, causing the speaker diaphragm 20 to deviate from the equilibrium position, thereby causing the sound quality of the sound-generating device to deteriorate.

[0050] In this embodiment, the stress retention rate of the speaker diaphragm 20 during the stress relaxation process is greater than or equal to 54%. In a high water pressure use environment, the speaker diaphragm 20 has good resilience when the external force is withdrawn, so that the sound quality of the sound-generating device is good.

[0051] In one embodiment, the room temperature damping factor of the speaker diaphragm 20 is greater than or equal to 0.12; and / or the room temperature storage modulus of the speaker diaphragm 20 is 2 MPa to 100 MPa.

[0052] When the room temperature damping factor is less than 0.12, the polarization phenomenon of the speaker diaphragm 20 is serious. In this embodiment, the room temperature damping factor of the speaker diaphragm 20 is within the above range, which can ensure that the sound-generating device using the speaker diaphragm 20 of the utility model has good anti-polarization performance, and the speaker diaphragm 20 will not be polarized during the vibration process. In addition, in the water pressure test, the stress loss of the speaker diaphragm 20 is small, so that the speaker diaphragm 20 can have a large stress retention rate, which can ensure that the speaker diaphragm 20 returns to the equilibrium position after the water pressure external force is withdrawn.

[0053] In this embodiment, the room temperature damping factor of the loudspeaker diaphragm 20 can be adjusted by adjusting the thickness ratio of the thermoplastic polyurethane elastomer film layer 22 .

[0054] The room temperature damping factor of the loudspeaker diaphragm 20 may also be 0.14, 0.15, 0.18, 0.2 or 0.21, etc. Those skilled in the art may determine the damping factor according to actual conditions, and no specific limitation is made here.

[0055] In this embodiment, the room temperature storage modulus of the speaker diaphragm 20 is 2MPa to 100MPa. The room temperature storage modulus is a physical parameter that describes the ability of a material to store elastic deformation energy at room temperature. The higher the room temperature storage modulus, the higher the hardness of the material; the lower the room temperature storage modulus, the lower the hardness of the material. When the room temperature storage modulus is within this range, it can ensure that the hardness of the speaker diaphragm 20 meets the requirements, and the elastic properties of the speaker diaphragm 20 are good and the F0 is low. The sound-generating device 100 using the speaker diaphragm 20 has increased loudness and better bass effect.

[0056] Furthermore, the room temperature storage modulus may be 15 MPa to 70 MPa. For example, the room temperature storage modulus of the speaker diaphragm 20 may be 20 MPa, 30 MPa, 40 MPa, 50 MPa or 60 MPa, etc. Those skilled in the art may determine the actual situation, and no specific limitation is made here.

[0057] For example, the room temperature storage modulus test method can be carried out according to the ASTM D882 standard. The test is carried out using a tensile testing machine. The tensile testing machine clamps a material sample of a set size and then stretches it. During the test, the ambient temperature is 23±2°C, the relative humidity is 50±5%, the heating rate of the test environment is 3°C / min, the strain of the material sample is 0.2%, and the stretching rate is 300mm / min.

[0058] In one embodiment, the thickness of the loudspeaker diaphragm 20 is 20 μm to 150 μm; and / or the thickness of the thermoplastic polyurethane elastomer film layer 22 in the loudspeaker diaphragm 20 accounts for 20% to 60%.

[0059] The density of thermoplastic polyurethane elastomer is lower than that of ethylene-acrylate rubber. By setting the thickness of the speaker diaphragm 20 and the thickness ratio of the thermoplastic polyurethane elastomer film layer 22, the mass of the speaker diaphragm 20 can be adjusted, and the low-frequency performance of the speaker diaphragm 20 can be adjusted.

[0060] In this embodiment, when the thickness of the thermoplastic polyurethane elastomer film layer 22 is less than 20%, the effect of reducing the mass of the speaker diaphragm 20 is not obvious, and the technical requirements for the use of the speaker cannot be met. When the thickness is greater than 60%, the proportion of the thermoplastic polyurethane elastomer film layer 22 in the speaker diaphragm 20 is too high. Since the glass transition point of the thermoplastic polyurethane elastomer film layer 22 is relatively high, the acoustic performance of the speaker diaphragm 20 will change greatly with temperature, affecting the auditory comfort of the sound-emitting device.

[0061] In this embodiment, by setting the thickness of the thermoplastic polyurethane elastomer film layer 22 to 20μm to 120μm, the thickness of the thermoplastic polyurethane elastomer film layer 22 accounts for 20% to 60%, which can effectively reduce the mass of the speaker diaphragm 20, and the storage modulus of the speaker diaphragm 20 is moderate and the low-frequency performance is excellent.

[0062] In addition, within the above thickness and thickness ratio range, the stress retention rate of the speaker diaphragm 20 can meet the use requirements. For example, the stress retention rate of the speaker diaphragm 20 during the stress relaxation process is greater than or equal to 54%. This allows the speaker diaphragm 20 to maintain a good sound effect.

[0063] In this embodiment, when the thermoplastic polyurethane elastomer film layer 22 is a single layer, the single layer of thermoplastic polyurethane elastomer film layer 22 accounts for 20% to 60%. When the thermoplastic polyurethane elastomer film layer 22 is a multi-layer, the total thickness of the multi-layer thermoplastic polyurethane elastomer film layer 22 accounts for 20% to 60%.

[0064] The thickness of the speaker diaphragm 20 can be 30 μm, 50 μm, 70 μm, 80 μm or 110 μm, etc., which can be determined by those skilled in the art according to the actual situation, and is not specifically limited here. The thickness of the thermoplastic polyurethane elastomer film layer 22 can be 20%, 24%, 30%, 35%, 40%, 45%, 50% and 60%, etc., which can be determined by those skilled in the art according to the actual situation, and is not specifically limited here.

[0065] In one embodiment, the density of the speaker diaphragm 20 is 1.1 g / cm 3 Up to 1.5g / cm 3 .

[0066] The smaller the density of the speaker diaphragm 20, the greater the thickness of the speaker diaphragm 20 at the same mass, resulting in a smaller vibration space of the speaker diaphragm 20; the greater the density of the speaker diaphragm 20, the greater the mass of the speaker diaphragm 20 at the same thickness, resulting in a smaller vibration amplitude of the speaker diaphragm 20 and poor mid-frequency performance. The density of the speaker diaphragm 20 is within this range, which can ensure that the density of the speaker diaphragm 20 is moderate, the overall mass is small, the thickness is small, and the speaker diaphragm 20 has excellent mid-frequency performance.

[0067] In this embodiment, the density of the speaker diaphragm 20 can be adjusted by adjusting the proportion of the thermoplastic polyurethane elastomer film layer 22, so that the density of the speaker diaphragm 20 meets the requirements. For example, by setting the thickness of the thermoplastic polyurethane elastomer film layer 22 to 20 μm to 120 μm, the thickness of the thermoplastic polyurethane elastomer film layer 22 accounts for 20% to 60%, so that the density of the speaker diaphragm 20 is 1.1 g / cm 3 Up to 1.5g / cm 3 .

[0068] The density of the speaker diaphragm 20 can be 1.2 g / cm 3 , 1.3g / cm 3 or 1.4 g / cm 3 The above method can be determined by those skilled in the art according to the actual situation and is not specifically limited here.

[0069] In one embodiment, the speaker diaphragm 20 includes a layer of the ethylene acrylate rubber film layer 21 and a layer of the thermoplastic polyester elastomer film layer 22 , and the ethylene acrylate rubber film layer 21 is bonded to one side of the thermoplastic polyester elastomer film layer 22 .

[0070] In this embodiment, when not cured, the ethylene-acrylate rubber is sticky, and the thermoplastic polyurethane elastomer film layer 22 can be first bonded to the ethylene-acrylate rubber film layer 21, and then the ethylene-acrylate rubber film layer 21 can be cured. For example, an amine cross-linking agent is used to cross-link the ethylene-acrylate rubber film layer 21 for curing. During the curing process, the ethylene-acrylate rubber film layer 21 and the thermoplastic polyurethane elastomer film layer 22 form a stable bond.

[0071] In this embodiment, the ethylene-acrylate rubber film layer 21 and the thermoplastic polyurethane elastomer film layer 22 are directly bonded together without the need for an adhesive therebetween. This composite method makes it easier to prepare the loudspeaker diaphragm 20.

[0072] like Figure 2 As shown, the speaker diaphragm 20 is formed into a two-layer composite structure, which includes a layer of the ethylene-acrylate rubber film layer 21 and a layer of the thermoplastic polyurethane elastomer film layer 22. The thermoplastic polyurethane elastomer film layer 22 is bonded to one side of the ethylene-acrylate rubber film layer 21 along the thickness direction. The structure of the speaker diaphragm 20 is simple, and the processing technology is simple. The thickness of the speaker diaphragm 20 can be made thinner.

[0073] In one embodiment, the speaker diaphragm 20 includes one layer of the ethylene acrylate rubber film layer 21 and two layers of the thermoplastic polyester elastomer film layers 22 , and the ethylene acrylate rubber film layer 21 is located between the two layers of the thermoplastic polyester elastomer film layers 22 .

[0074] like Figure 3 As shown, the ethylene-acrylate rubber film layer 21 is set as one layer, and the thermoplastic polyurethane elastomer film layer 22 is set as two layers. That is, the thermoplastic polyurethane elastomer film layer 22 is the epidermis layer, and the ethylene-acrylate rubber film layer 21 is the middle layer. The two layers of thermoplastic polyurethane elastomer film layers 22 are respectively bonded to the two sides of the ethylene-acrylate rubber film layer 21 along the thickness direction. During preparation, the two layers of thermoplastic polyurethane elastomer layers 22 are bonded to the two sides of the ethylene-acrylate rubber film layer 21, and the two epidermis layers and the middle layer are bonded together through one-time curing. This makes the preparation of the speaker diaphragm 20 easy. In addition, the two layers of thermoplastic polyurethane elastomer film layers 22 are used as the epidermis layer of the speaker diaphragm 20. Since the thermoplastic polyurethane elastomer film layer 22 has the characteristics of high strength, toughness, oil resistance, temperature resistance, etc., it can significantly improve the durability, stability and temperature resistance of the speaker diaphragm 20. The ethylene-acrylate rubber film layer 21 as the intermediate layer can make the speaker diaphragm 20 have good damping properties and good elasticity.

[0075] In one embodiment, the speaker diaphragm 20 includes two layers of the ethylene-acrylate rubber film layers 21 and one layer of the thermoplastic polyester elastomer film layer 22 , and the thermoplastic polyester elastomer film layer 22 is located between the two layers of the ethylene-acrylate rubber film layers 21 .

[0076] like Figure 4 As shown, the ethylene-acrylate rubber film layer 21 is set as two layers, and the thermoplastic polyurethane elastomer film layer 22 is a single layer. That is, the thermoplastic polyurethane elastomer film layer 22 is the middle layer, and the ethylene-acrylate rubber film layer 21 is the skin layer. The two layers of ethylene-acrylate rubber film layers 21 are respectively bonded to the two sides of the thermoplastic polyurethane elastomer film layer 22 along the thickness direction. The ethylene-acrylate rubber film layer 21 has good tensile strength and elastic recovery rate, which enables the speaker diaphragm 20 to undergo elastic deformation when subjected to external force, reducing the risk of deformation and damage of the speaker diaphragm 20.

[0077] In one embodiment, the reinforcing agent of the ethylene-acrylate rubber film layer 21 is at least one of talc, silicon dioxide, and carbon black.

[0078] In this embodiment, the reinforcing agent can improve the mechanical strength of the ethylene-acrylate rubber membrane layer 21 , thereby improving the overall strength and vibration stability of the speaker diaphragm 20 .

[0079] Take the reinforcing agent as talcum powder as an example for explanation. Talc is an amorphous non-metallic material, and the surface of talcum powder has been modified to have hydrogen, carboxyl and other groups that can undergo substitution, reduction, oxidation reaction, etc. When talcum powder is added to ethylene-acrylate rubber, due to the strong interaction between the groups on the surface of talcum powder and the interface of ethylene-acrylate material, the molecular chain of ethylene-acrylate rubber is easier to slide on the surface of talcum powder when it is stressed, but it is not easy to separate from talcum powder. Ethylene-acrylate rubber and talcum powder form a strong bond that can slide, so that the mechanical strength of ethylene-acrylate rubber film layer 21 is increased.

[0080] In this embodiment, the weight percentage of the reinforcing agent is 35 wt % to 62 wt %.

[0081] For example, the reinforcing agent is talcum powder, as shown in Table 1, which shows the elongation at break and tensile strength of the speaker diaphragm 20 at different talcum powder contents. The thickness of the speaker diaphragm 20 is 85 μm. The thickness of the thermoplastic polyurethane elastomer film layer 22 is 40 μm.

[0082] Table 1 Elongation at break and tensile strength of loudspeaker diaphragm 20

[0083]

[0084] As shown in Table 1, when the content of talcum powder is between 35wt% and 62wt%, the elongation at break and the tensile strength of the loudspeaker diaphragm 20 are both relatively high and can meet the use requirements.

[0085] When the content of talcum powder is lower than 35wt%, the speaker diaphragm 20 is easily deformed due to the insufficient strength of the ethylene-acrylate rubber film layer 21, and the yield of the speaker diaphragm 20 is low. When the content of talcum powder is higher than 62wt%, the elongation at break and the tensile strength of the ethylene-acrylate rubber film layer 21 are significantly reduced, resulting in insufficient material toughness, a low stress retention rate of the speaker diaphragm 20 during stress relaxation, and a membrane breakage phenomenon is prone to occur during the vibration of the speaker diaphragm 20. The mass proportion of the reinforcing agent is 35wt% to 62wt%. Within this range, the speaker diaphragm 20 has high strength, flexibility and stress retention rate.

[0086] In this embodiment, the content of the reinforcing agent in the ethylene-acrylate rubber membrane layer 21 can also be 40wt%, 45wt%, 55wt% or 60wt%, etc. The above values ​​can make the speaker diaphragm 20 have high strength, flexibility and stress retention rate.

[0087] In addition, silicon dioxide as a reinforcing agent can improve the hardness, durability and vibration stability of the ethylene-acrylate rubber film layer 21. Carbon black as a reinforcing agent can improve the hardness, stability and antistatic ability of the ethylene-acrylate rubber film layer 21.

[0088] Of course, the reinforcing agent may also be other types or a combination of multiple types, and those skilled in the art may determine according to actual conditions, and no specific limitation is made here.

[0089] In one embodiment, the ethylene-acrylate rubber film layer 21 contains an antioxidant, and the antioxidant includes at least one of antioxidant N-445, antioxidant 246, antioxidant 4010, antioxidant SP, antioxidant RD, antioxidant ODA, antioxidant OD, and antioxidant WH-02.

[0090] In this embodiment, during the use of the speaker diaphragm 20, as the use time increases, the molecular chains in the ethylene-acrylate rubber film layer 21 will break and generate free radicals, and the free radicals can accelerate the aging of the ethylene-acrylate rubber film layer 21. Adding an antioxidant to the ethylene-acrylate rubber film layer 21 can stop the generation of free radicals in the ethylene-acrylate rubber film layer 21, thereby slowing down the aging speed of the ethylene-acrylate rubber film layer 21.

[0091] In this embodiment, the antioxidant accounts for 0.2wt% to 5wt% by weight. By adding the antioxidant within this ratio, the service life of the speaker diaphragm 20 can be extended, and the antioxidant can be ensured to have good compatibility with the ethylene-acrylate rubber in the ethylene-acrylate rubber film layer 21. The antioxidant is evenly dispersed in the ethylene-acrylate rubber, thereby avoiding local aging of the ethylene-acrylate rubber film layer 21 due to the low local concentration of the antioxidant in the ethylene-acrylate rubber.

[0092] Furthermore, the weight percentage of the antioxidant may be 0.5 wt % to 3 wt %. For example, the weight percentage of the antioxidant may be 1 wt %, 1.5 wt % or 2 wt %, etc., which may be determined by those skilled in the art according to actual conditions and is not specifically limited here.

[0093] The speaker diaphragm 20 of the present invention is described in detail below 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.

[0094] Example:

[0095] The speaker diaphragm 20 of the utility model comprises a laminated ethylene-acrylate rubber film layer 21 and a thermoplastic polyurethane elastomer film layer 22. The thickness of the speaker diaphragm 20 is 85 μm, and the density of the speaker diaphragm 20 is 1.22 g / cm 3， The thickness of the ethylene-acrylate rubber film layer 21 is 50 μm, the thickness of the thermoplastic polyurethane elastomer film layer 22 is 35 μm, and the melting point is 182° C. The glass transition point of the ethylene-acrylate rubber film layer 21 is -28° C., the room temperature storage modulus is 6.7 Mpa, the room temperature damping factor is 0.15, and the stress retention rate is 62%.

[0096] like Figure 5 As shown, Figure 5 The harmonic distortion curve of the sound-generating device using the speaker diaphragm 20 of the above embodiment is tested at a voltage of 3.1 V and before and after the air pressure is 0.5 atm and the air is inflated for 30 minutes. The horizontal axis represents the vibration frequency in Hz. In this embodiment, the vibration frequency ranges from 100 Hz to 10000 Hz. The vertical axis represents the harmonic distortion in %. Figure 5 In the figure, the distortion curve before inflation is represented by the distortion curve before stretching, and the distortion curve after inflation for 30 minutes is represented by the distortion curve after stretching. Figure 5 It can be seen that the distortion of the loudspeaker diaphragm 20 of the present invention remains basically unchanged before and after stretching, and the sound quality is stable.

[0097] Comparative Example 1:

[0098] A conventional rubber membrane layer is used as the speaker diaphragm 20. The diaphragm is made of AEM rubber material. The thickness of the rubber membrane layer is 95 μm and the density is 1.23 g / cm 3 , the glass transition point is -28°C, the room temperature storage modulus is 5.8MPa, the stress retention rate is 51%, and the room temperature damping factor is 0.16. The outer dimensions of the loudspeaker diaphragm 20 of the comparative example 1 are consistent with the outer dimensions of the loudspeaker diaphragm 20 of the embodiment of the utility model.

[0099] like Figure 6 As shown, Figure 6 The harmonic distortion curve of the sound-generating device using the diaphragm of the comparative example 1 is tested at a voltage of 3.1V and before and after the air pressure is 0.5 atm and the air is inflated for 30 minutes. The horizontal axis represents the vibration frequency in Hz. In this embodiment, the intermediate frequency ranges from 100 Hz to 10000 Hz; the vertical axis represents the distortion. Figure 6 In the figure, the distortion curve before inflation is shown by the distortion curve before stretching, and the distortion curve after inflation for 30 minutes is shown by the distortion curve after stretching. Figure 6 It can be seen that after the diaphragm of comparative example 1 is stretched, the distortion increases significantly and the sound quality decreases.

[0100] Comparative Example 2:

[0101] A conventional single-layer thermoplastic polyurethane elastomer film layer 22 is used as the diaphragm. The density of the thermoplastic polyurethane elastomer film layer 22 is 1.20 g / cm 3 , the glass transition point is 3° C., the room temperature storage modulus is 8 MPa, and the stress retention rate is 72%. The outer dimensions of the loudspeaker diaphragm 20 of the comparative example 2 are consistent with the outer dimensions of the loudspeaker diaphragm 20 of the embodiment of the utility model.

[0102] Although a single-layer thermoplastic polyurethane elastomer diaphragm has a large stress retention rate, due to the high glass transition point of the thermoplastic polyurethane elastomer membrane layer 22, the diaphragm of the single-layer thermoplastic polyurethane elastomer membrane layer 22 will cause a large difference in performance between -20°C and room temperature during use, causing the performance of the sound-emitting device 100 to vary greatly with temperature, thereby affecting the user's listening experience.

[0103] According to another embodiment of the present invention, a sound generating device 100 is provided. Figure 1 As shown, the sound-generating device 100 includes the speaker diaphragm 20 of the above embodiment.

[0104] In this embodiment, the sound-generating device 100 prepared by the speaker diaphragm 20 of the above embodiment has a high stress retention rate and low stress loss. After the external force is pulled out, the speaker diaphragm 20 can rebound so that the speaker diaphragm 20 can rebound to a balanced position, thereby ensuring good sound quality of the sound-generating device. Of course, the sound-generating device 100 of the present utility model also includes at least all the beneficial effects of the above embodiments, which will not be elaborated here.

[0105] In this embodiment, the sound-generating device 100 may be a sound-generating device such as a speaker unit or a speaker assembly, and those skilled in the art may determine it according to actual conditions, and no specific limitation is made here.

[0106] like Figure 1 As shown, the sound-generating device 100 may include a housing 10, a magnetic circuit system and a vibration system, wherein the magnetic circuit system includes a permanent magnet 40, and the permanent magnet 40 is used to form a magnetic gap. The vibration system includes a speaker diaphragm 20 and a voice coil 30. The speaker diaphragm 20 and the permanent magnet 40 are both connected to the housing 10. The permanent magnet 40 is arranged on one side of the speaker diaphragm 20 along the vibration direction of the voice coil 30. One end of the voice coil 30 is connected to the speaker diaphragm 20, and the other end is located in the magnetic gap.

[0107] In this embodiment, the speaker diaphragm 20 may be a folded ring diaphragm. The folded ring diaphragm includes a central portion, a folded ring portion, and a fixed portion connected in sequence from the inside to the outside. The fixed portion is used to connect to the housing 10. The central portion is provided with a dome, and the voice coil 20 is connected to the central portion.

[0108] In other examples, the speaker diaphragm 20 may also be a flat diaphragm or other structures. Those skilled in the art may determine this according to actual conditions, and no specific limitation is made here.

[0109] According to another embodiment of the present invention, an electronic device is provided. The electronic device includes the sound generating device 100 described in the above embodiment. 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.

[0110] The electronic device may be a mobile phone, a stereo, a tablet computer, a laptop computer, or the like, or may be a device used for underwater work, etc. Those skilled in the art may determine the method according to actual conditions, and no specific limitation is made here.

[0111] 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.

[0112] Although some specific embodiments of the present invention 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 invention. 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 invention. The scope of the present invention is defined by the appended claims.

Claims

1. A loudspeaker diaphragm, characterized in that: include: An ethylene-acrylate rubber film layer and a thermoplastic polyurethane elastomer film layer are stacked; The glass transition point of the ethylene-acrylate rubber film layer is -20°C to -60°C, and the melting point of the thermoplastic polyurethane elastomer film layer is greater than or equal to 170°C.

2. The loudspeaker diaphragm according to claim 1, characterized in that: The stress retention rate of the loudspeaker diaphragm during the stress relaxation process is greater than or equal to 54%.

3. The loudspeaker diaphragm according to claim 1, characterized in that: The room temperature damping factor of the loudspeaker diaphragm is greater than or equal to 0.12; And / or, the room temperature storage modulus of the speaker diaphragm is 2 MPa to 100 MPa.

4. The loudspeaker diaphragm according to claim 1, characterized in that: The thickness of the speaker diaphragm is 20 μm to 150 μm; And / or, the thickness of the thermoplastic polyurethane elastomer film layer in the speaker diaphragm accounts for 20% to 60%.

5. The loudspeaker diaphragm according to claim 1, characterized in that: The density of the speaker diaphragm is 1.1 g / cm 3 Up to 1.5g / cm 3 .

6. The loudspeaker diaphragm according to claim 1, characterized in that: The loudspeaker diaphragm comprises a layer of the ethylene-acrylate rubber film layer and a layer of the thermoplastic polyester elastomer film layer, wherein the ethylene-acrylate rubber film layer is bonded to one side of the thermoplastic polyester elastomer film layer.

7. The loudspeaker diaphragm according to claim 1, characterized in that: The loudspeaker diaphragm comprises one layer of the ethylene-acrylate rubber film layer and two layers of the thermoplastic polyester elastomer film layers, wherein the ethylene-acrylate rubber film layer is located between the two layers of the thermoplastic polyester elastomer film layers.

8. The loudspeaker diaphragm according to claim 1, characterized in that: The loudspeaker diaphragm comprises two layers of the ethylene-acrylate rubber film layers and one layer of the thermoplastic polyester elastomer film layer, wherein the thermoplastic polyester elastomer film layer is located between the two layers of the ethylene-acrylate rubber film layers.

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

10. An electronic device comprising the sound generating device according to claim 9.

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