Loudspeaker diaphragm, sound production device and electronic equipment

Abstract

The utility model discloses a loudspeaker diaphragm, a sound production device and electronic equipment. The loudspeaker diaphragm comprises an ethylene-acrylate rubber film layer and a thermoplastic polyester elastomer film layer which are laminated, the glass transition point of the ethylene-acrylate rubber film layer is-20 DEG C to-60 DEG C, and the glass transition point of the thermoplastic polyester elastomer film layer is-10 DEG C to-60 DEG C or 10 DEG C to 30 DEG C. The loudspeaker diaphragm provided by the utility model is small in mass, and the sound production device employing the loudspeaker diaphragm can have good intermediate frequency loudness.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic equipment, 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 a speaker, especially a miniature sound-generating device, is usually made of rubber material. Although the rubber diaphragm has good rebound performance, the rubber material has a high density and the diaphragm is thick, resulting in a large mass of the diaphragm. The mass of the diaphragm accounts for a relatively high proportion in the entire vibration system, resulting in insufficient mid-frequency loudness of the miniature speaker, which cannot meet the user's listening needs.

[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 loudspeaker diaphragm.

[0005] According to a first aspect of the present invention, a loudspeaker diaphragm is provided. The loudspeaker diaphragm comprises:

[0006] An ethylene-acrylate rubber film layer and a thermoplastic polyester elastomer film layer are stacked;

[0007] The glass transition point of the ethylene-acrylate rubber film layer is -20°C to -60°C, and the glass transition point of the thermoplastic polyester elastomer film layer is -10°C to -60°C or 10°C to 30°C.

[0008] Optionally, the stress retention rate of the loudspeaker diaphragm is greater than or equal to 45%.

[0009] Optionally, the room temperature storage modulus of the loudspeaker diaphragm is 20 MPa to 150 MPa; and / or the density of the loudspeaker diaphragm is 1.1 g / cm 3 Up to 1.5g / cm 3 .

[0010] Optionally, the speaker diaphragm has a thickness of 20 μm to 120 μm.

[0011] Optionally, the thickness of the thermoplastic polyester elastomer film layer accounts for 15% to 50%.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] According to a second aspect of the utility model, a sound-generating device is provided, which includes the loudspeaker diaphragm of the above embodiment.

[0016] According to a third aspect of the present invention, an electronic device is provided, which includes the sound generating device of the above embodiment.

[0017] One technical effect of the utility model is that the loudspeaker diaphragm comprises a stacked ethylene-acrylate rubber film layer and a thermoplastic polyester elastomer film layer, the glass transition point of the ethylene-acrylate rubber film layer is -20°C to -60°C, the glass transition point of the thermoplastic polyester elastomer film layer is -10°C to -60°C or 10°C to 30°C. The loudspeaker diaphragm of the utility model forms a diaphragm by compounding the ethylene-acrylate rubber film layer and the thermoplastic polyester elastomer film layer, which not only has low modulus and high damping, but also has a smaller mass, so that the sound-generating device using the loudspeaker diaphragm can have good mid-frequency loudness.

[0018] 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

[0019] 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.

[0020] Figure 1 It is a structural schematic diagram of a sound-generating device according to an embodiment of the utility model.

[0021] Figure 2 It is a structural schematic diagram of a loudspeaker diaphragm according to an embodiment of the utility model.

[0022] Figure 3 It is a structural schematic diagram of a loudspeaker diaphragm according to another embodiment of the utility model.

[0023] Figure 4 It is a structural schematic diagram of a loudspeaker diaphragm according to another embodiment of the utility model.

[0024] Figure 5 This is a mid-frequency loudness curve of a loudspeaker diaphragm according to an embodiment of the present invention.

[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 polyester 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 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.

[0029] 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.

[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 embodiments shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other embodiments 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 invention, a speaker diaphragm 20 is provided. Figures 1 to 4 As shown, the speaker diaphragm 20 includes a laminated ethylene-acrylate rubber (Alpha-Ethylmescaline Rubber, AEM rubber for short) film layer 21 and a thermoplastic polyester elastomer (Thermoplastic Polyester Elastomer, TPEE for short) film layer 22. The glass transition point of the ethylene-acrylate rubber film layer 21 is -20°C to -60°C, and the glass transition point of the thermoplastic polyester elastomer film layer 22 is -10°C to -60°C or 10°C to 30°C.

[0034] In this embodiment, the loudspeaker diaphragm 20 includes a stacked ethylene-acrylate rubber film layer 21 and a thermoplastic polyester elastomer film layer 22. The loudspeaker diaphragm 20 of the utility model forms a diaphragm by compounding the ethylene-acrylate rubber film layer 21 and the thermoplastic polyester elastomer film layer 22. It can not only take into account low modulus and high damping, but also has a smaller mass, so that the sound-generating device 100 using the loudspeaker diaphragm 20 can have good mid-frequency loudness. For example, the ethylene-acrylate rubber film layer 21 and the thermoplastic polyester elastomer film layer 22 are in direct contact and bonded together to form a composite diaphragm. The ethylene-acrylate rubber film layer 21 is made of ethylene-acrylate rubber. Ethylene-acrylate rubber is made of ethylene and methyl acrylate as main raw materials, and is polymerized by high pressure heating under the action of a cross-linking agent.

[0035] Preferably, the ethylene-acrylate rubber is a ternary structure, and the molecular formula is:

[0036] Wherein, x, y, z are natural numbers, R and R' are alkyl groups, and the specific values ​​of x, y, z and the specific structure of R / R' are not limited here.

[0037] 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.

[0038] In the utility model, 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 the molecular formula, the R group is bonded to the ethylene with the double bonds opened and the methyl acrylate with the 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 carboxyl 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 easier.

[0039] 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.

[0040] Of course, in other examples, the ethylene-acrylate rubber may not contain the third unit.

[0041] The thermoplastic polyester elastomer film layer 22 is prepared from a thermoplastic polyester elastomer. Thermoplastic polyester elastomer is a block copolymer, usually composed of a polyester hard segment and a polyether or aliphatic polyester soft segment. Optionally, the material of the polyester hard segment is selected from a polymer of a dibasic acid and a diol. For example, the dibasic acid is selected from one or more of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid and biphenyl dicarboxylic acid. The diol is selected from one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol. The material of the polyether or aliphatic polyester soft segment is selected from one or more of aliphatic polyester, polytetramethylene ether, polyphenylene ether, polypropylene oxide, and polyethylene oxide. The grades of thermoplastic polyester elastomers include, for example, D40, D50, D55, D63, etc. The thermoplastic polyester elastomer film layer 22 has good flexibility, high and low temperature resistance, and vibration stability. The density of the thermoplastic polyester elastomer film layer 22 is lower than that of the ethylene-acrylate rubber film layer 21, thereby being able to reduce the overall density and overall mass of the speaker diaphragm 20. Thus, under the same driving force, the speaker diaphragm 20 of the embodiment of the utility model has a larger amplitude, and the sound-generating device 100 using the speaker diaphragm 20 has a greater mid-frequency loudness.

[0042] The speaker diaphragm 20 is a composite of an ethylene-acrylate rubber film layer 21 and a thermoplastic polyester 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 a sound), the thickness of the speaker diaphragm 20 of the utility model is relatively small. For example, the speaker diaphragm 20 of the utility model can be reduced by 30% compared with only using ethylene-acrylate rubber as the speaker diaphragm 20, and thus the mass of the speaker diaphragm 20 can be reduced by 30%. And the sound-generating device 100 using the speaker diaphragm 20 can have a higher mid-frequency loudness.

[0043] 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, changes from a glass state to a highly elastic state. That is, when the temperature is higher than the glass transition point, the material, such as 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.

[0044] 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 a normal use temperature (eg, -10°C to 10°C), thereby making the speaker diaphragm 20 more elastic.

[0045] The glass transition point of the thermoplastic polyester elastomer film layer 22 is -10°C to -60°C. Similarly, the glass transition point of the thermoplastic polyester elastomer film layer 22 is -10°C to -60°C, which enables the thermoplastic polyester elastomer film layer 22 to be in a highly elastic state at a normal use temperature, thereby making the elasticity of the speaker diaphragm 20 relatively high. When the glass transition point of the thermoplastic polyester elastomer film layer 22 is 10°C to 30°C, the thermoplastic polyester elastomer film layer 22 can be in a glass state at a normal use temperature, thereby making the hardness of the speaker diaphragm 20 relatively high. Regardless of whether the glass transition point of the thermoplastic polyester elastomer film layer 22 is -10°C to -60°C or 10°C to 30°C, the thermoplastic polyester elastomer film layer 22 maintains a stable state, i.e., a glass state or a highly elastic state, at a normal use temperature, and the thermoplastic polyester elastomer film layer 22 does not transition between the glass state and the highly elastic state. Since the elasticity of the speaker diaphragm 20 changes during this transition process, the vibration amplitude of the speaker diaphragm 20 changes, and the sound effect is unstable. In the present invention, by controlling the glass transition temperature of the ethylene-acrylate rubber film layer 21 and the thermoplastic polyester elastomer film layer 22, the vibration consistency and stability of the speaker diaphragm 20 are significantly improved at normal use temperature, especially in the mid-frequency range, the sound performance of the speaker diaphragm 20 is stable.

[0046] For example, the above-mentioned test method for the glass transition point can be tested in accordance with the ASTM D882 standard. Specifically, a tensile testing machine is used to test the change in the loss factor of the material with temperature. 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 sample is 0.2%. The temperature corresponding to the peak value of the loss factor of the material sample is the glass transition point. Of course, the test method for the glass transition point is not limited to the above embodiment, and those skilled in the art can set it according to actual needs.

[0047] 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.

[0048] 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 .

[0049] 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.

[0050] In this embodiment, the weight percentage of the reinforcing agent is 35 wt % to 62 wt %.

[0051] 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 75 μm. The thickness of the thermoplastic polyester elastomer film layer 22 is 20 μm.

[0052] Table 1 Elongation at break and tensile strength of loudspeaker diaphragm 20

[0053]

[0054] 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.

[0055] 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 membrane 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 membrane layer 21 are significantly reduced, resulting in insufficient material toughness, a low stress retention rate of the speaker diaphragm 20 during stress relaxation, and the speaker diaphragm 20 is prone to membrane rupture during vibration.

[0056] In this embodiment, the content of the reinforcing agent in the ethylene-acrylate rubber film layer 21 can also be 40wt%, 45wt%, 55wt% or 60wt%, etc. Those skilled in the art can determine it according to actual conditions, and no specific limitation is made here.

[0057] 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.

[0058] 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.

[0059] In one embodiment, the stress retention rate of the loudspeaker diaphragm 20 during the stress relaxation process is greater than or equal to 45%.

[0060] 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.

[0061] 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 causes stress loss due to internal friction. If the stress retention rate is less than 45%, the stress loss of the speaker diaphragm 20 is 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 100 to deteriorate.

[0062] In this embodiment, the stress retention rate of the speaker diaphragm 20 during the stress relaxation process is greater than or equal to 45%. 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 device 100 is good.

[0063] In one embodiment, the thickness of the speaker diaphragm 20 is 20 μm to 120 μm. By setting the thickness of the speaker diaphragm 20 , the weight of the speaker diaphragm 20 can be effectively controlled.

[0064] In this embodiment, the thickness of the thermoplastic polyester elastomer film layer 22 accounts for 15% to 50%.

[0065] The density of thermoplastic polyester 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 polyester 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.

[0066] In this embodiment, when the thickness of the thermoplastic polyester elastomer film layer 22 is less than 15%, 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 50%, although the mass of the speaker diaphragm 20 is reduced, the storage modulus of the speaker diaphragm 20 is too high, which will cause the low-frequency performance of the sound-generating device 100 to be low and cannot meet the sound requirements of the sound-generating device 100.

[0067] In this embodiment, by setting the thickness of the thermoplastic polyester elastomer film layer 22 to 20 μm to 120 μm, the thickness of the thermoplastic polyester elastomer film layer 22 accounts for 15% to 50%, which can further effectively reduce the mass of the speaker diaphragm 20, and the speaker diaphragm 20 has a moderate storage modulus and excellent low-frequency performance.

[0068] 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 45%. This allows the speaker diaphragm 20 to maintain a good sound effect.

[0069] In this embodiment, when the thermoplastic polyester elastomer film layer 22 is a single layer, the single layer of thermoplastic polyester elastomer film layer 22 accounts for 15% to 50%. When the thermoplastic polyester elastomer film layer 22 is a multi-layer, the total thickness of the multi-layer thermoplastic polyester elastomer film layer 22 accounts for 15% to 50%.

[0070] 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 actual conditions, and is not specifically limited here. The thickness of the thermoplastic polyester elastomer film layer 22 can be 18%, 24%, 30%, 35%, 40% or 45%, etc., which can be determined by those skilled in the art according to actual conditions, and is not specifically limited here.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] In one embodiment, the room temperature storage modulus of the speaker diaphragm 20 is 20 MPa to 150 MPa; and / or the density of the speaker diaphragm 20 is 1.1 g / cm 3 Up to 1.5g / cm 3 .

[0076] 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 and the lower the elasticity; the lower the room temperature storage modulus, the lower the hardness of the material, the lower the elasticity and the higher the damping performance. 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 performance of the speaker diaphragm 20 is good, and F0 is low. The sound-generating device 100 using the speaker diaphragm 20 has increased loudness and better bass effect.

[0077] Furthermore, the room temperature storage modulus may be 30 MPa to 100 MPa. For example, the room temperature storage modulus of the speaker diaphragm 20 may be 40 MPa, 50 MPa, 60 MPa, 70 MPa or 80 MPa, etc. Those skilled in the art may determine this according to actual conditions, and no specific limitation is made here.

[0078] 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.

[0079] 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.

[0080] In this embodiment, the density of the speaker diaphragm 20 can be adjusted by adjusting the proportion of the thermoplastic polyester 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 polyester elastomer film layer 22 to 20 μm to 120 μm, the thickness of the thermoplastic polyester elastomer film layer 22 accounts for 15% to 50%, so that the density of the speaker diaphragm 20 is 1.1 g / cm 3 Up to 1.5g / cm 3 .

[0081] The density of the speaker diaphragm 20 can be 1.2 g / cm 3 , 1.3g / cm 3 , 1.4g / 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.

[0082] In one embodiment, Figure 2 As shown, 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 .

[0083] In this embodiment, when not cured, the ethylene-acrylate rubber is sticky, and the thermoplastic polyester 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, by using an amine cross-linking agent 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 polyester elastomer film layer 22 form a stable bond.

[0084] In this embodiment, the ethylene-acrylate rubber film layer 21 and the thermoplastic polyester 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.

[0085] In this embodiment, 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 polyester elastomer film layer 22. The thermoplastic polyester 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.

[0086] In one embodiment, Figure 3 As shown, the loudspeaker diaphragm 20 includes a 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 .

[0087] like Figure 3 As shown, the ethylene-acrylate rubber film layer 21 is set as one layer, and the thermoplastic polyester elastomer film layer 22 is set as two layers. That is, the thermoplastic polyester 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 polyester 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 polyester elastomer film 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 polyester elastomer film layers 22 are used as the epidermis layer of the speaker diaphragm 20. Since the thermoplastic polyester 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.

[0088] In one embodiment, Figure 4 As shown, the loudspeaker 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 .

[0089] In this embodiment, the ethylene-acrylate rubber film layer 21 is set as two layers, and the thermoplastic polyester elastomer film layer 22 is one layer. That is, the thermoplastic polyester 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 polyester 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.

[0090] 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.

[0091] Example:

[0092] The speaker diaphragm 20 of the embodiment of the utility model comprises a laminated ethylene-acrylate rubber film layer 21 and a thermoplastic polyester elastomer film layer 22. The thickness of the speaker diaphragm 20 is 56 μm, wherein the thickness of the thermoplastic polyester elastomer film layer 22 is 12 μm, the thickness of the ethylene-acrylate rubber film layer 21 is 44 μm, and the density of the speaker diaphragm 20 is 1.41 g / cm 3 , the glass transition point is -39°C, the room temperature storage modulus is 51.4MPa, the stress retention rate is 59.8%, and the speaker diaphragm 20 is a diaphragm with a folded ring. The mass of the speaker diaphragm 20 is 6.68mg. By adjusting the physical parameters of the speaker diaphragm 20, the F0 of the sound-generating device 100 using the speaker diaphragm 20 is 748Hz. Among them, when performing the F0 test of the sound-generating device 100, the voltage of the sound-generating device 100 is 3.1V, and the frequency range is 100Hz to 14KHz.

[0093] Comparative Example 1:

[0094] A conventional rubber membrane layer is used as the speaker diaphragm 20. The diaphragm is made of AEM rubber. The thickness of the rubber membrane layer is 80 μm and the density is 1.55 g / cm 3 , the glass transition point is -36°C, the room temperature storage modulus is 18.1MPa, the mass of the speaker diaphragm 20 is 10.5mg, and the stress retention rate is 49.1%. The speaker diaphragm 20 of the comparative example 1 is a diaphragm with a folded ring. The outer dimensions of the speaker diaphragm 20 of the comparative example 1 are consistent with the outer dimensions of the speaker diaphragm 20 of the embodiment of the present invention. The F0 of the sound-generating device 100 using the speaker diaphragm 20 is 749Hz.

[0095] Figure 5The middle frequency response curves of the loudspeaker diaphragm 20 of comparative example 1 and the loudspeaker diaphragm 20 of the embodiment of the utility model are shown in FIG. 1 , wherein the horizontal axis represents the vibration frequency, in Hz, and in this embodiment, the middle frequency ranges from 1000 Hz to 10000 Hz; the vertical axis represents the loudness, in dB.

[0096] from Figure 5 It can be seen that when F0 is close, the mid-frequency loudness of the sound-generating device 100 using the loudspeaker diaphragm 20 of the embodiment of the utility model is significantly higher than the mid-frequency loudness of the sound-generating device 100 using the loudspeaker diaphragm 20 of comparative example 1.

[0097] In addition, when F0 is similar, the thickness and mass of the speaker diaphragm 20 of the present invention are significantly lower than those of the speaker diaphragm 20 of Comparative Example 1. The room temperature storage modulus and stress retention rate of the speaker diaphragm 20 of the present invention are significantly higher than those of the speaker diaphragm 20 of Comparative Example 1.

[0098] Comparative Example 2:

[0099] A conventional thermoplastic polyester elastomer film layer 22 is used as the speaker diaphragm 20. The glass transition point of the thermoplastic polyester elastomer is -30°C. The prepared speaker diaphragm 20 has a thickness of 45 μm and a density of 1.23 g / cm 3 , the room temperature storage modulus is 120.2MPa. The outer dimensions of the speaker diaphragm 20 of Comparative Example 2 are consistent with the outer dimensions of the speaker diaphragm 20 of the embodiment of the present invention. The F0 of the sound-generating device 100 using the speaker diaphragm 20 is 753Hz. Although the F0 of the sound-generating device 100 is similar to that of the embodiment of the present invention. However, due to the higher room temperature storage modulus of the thermoplastic polyester elastomer film layer 22. Under the same driving force, the amplitude of the speaker diaphragm 20 is small, and the low-frequency (for example, the frequency range is 100Hz to 700Hz) loudness of the sound-generating device 100 using the speaker diaphragm 20 is 1.5dB lower than the low-frequency loudness of the speaker diaphragm 20 of the embodiment of the present invention. Among them, when performing the frequency loudness test of the sound-generating device 100, the voltage of the sound-generating device 100 is 3.1V, and the frequency range is 100Hz to 14KHz.

[0100] 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.

[0101] In this embodiment, the sound device 100 prepared by the speaker diaphragm 20 of the above embodiment has a higher stress retention rate and better mid-frequency loudness. Of course, the sound device 100 of the present utility model also includes at least all the beneficial effects of the above embodiment, which will not be repeated here.

[0102] 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.

[0103] like Figure 1 As shown, in a specific embodiment of the utility model, 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] In this embodiment, the electronic device includes the sound generating device 100 of the above embodiment, so that the electronic device can have better intermediate frequency loudness.

[0109] 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.

[0110] Although some specific embodiments of the present invention have been described in detail through the embodiments, it should be understood by those skilled in the art that the above embodiments are only for illustration, not for limiting 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 polyester elastomer film layer are stacked; The glass transition point of the ethylene-acrylate rubber film layer is -20°C to -60°C, and the glass transition point of the thermoplastic polyester elastomer film layer is -10°C to -60°C or 10°C to 30°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 45%.

3. The loudspeaker diaphragm according to claim 1, characterized in that: The room temperature storage modulus of the speaker diaphragm is 20 MPa to 150 MPa; And / or, the density of the speaker diaphragm is 1.1 g / cm 3 Up to 1.5g / cm 3 .

4. The loudspeaker diaphragm according to claim 1, characterized in that: The thickness of the loudspeaker diaphragm is 20 μm to 120 μm.

5. The loudspeaker diaphragm according to claim 4, characterized in that: The thickness of the thermoplastic polyester elastomer film layer accounts for 15% to 50%.

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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