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 a thermoplastic polyurethane elastomer film layer and a thermoplastic polyester elastomer film layer which are laminated, and the thickness ratio of the thermoplastic polyurethane elastomer film layer in the loudspeaker diaphragm is not less than 30%. The loudspeaker diaphragm provided by the utility model comprises the thermoplastic polyurethane elastomer film layer and the thermoplastic polyester elastomer film layer which are arranged in a laminated manner, so that the loudspeaker diaphragm has the advantages of high damping and high and low temperature resistance, and the sound listening yield of a sound production device adopting the loudspeaker diaphragm provided by the utility model is greatly improved.

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 the sound-generating device of existing electronic products is generally made of thermoplastic polyester elastomer material, which has low damping, resulting in a low listening yield of the sound-generating device using thermoplastic polyester elastomer material, thus affecting the user's listening experience.

[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, comprising: a laminated thermoplastic polyurethane elastomer film layer and a thermoplastic polyester elastomer film layer, wherein the thermoplastic polyurethane elastomer film layer accounts for no less than 30% of the thickness of the loudspeaker diaphragm.

[0006] Optionally, the speaker diaphragm is formed as a two-layer composite structure, the two-layer composite structure includes a layer of the thermoplastic polyurethane elastomer film layer and a layer of the thermoplastic polyester elastomer film layer; or, the speaker diaphragm is formed as a three-layer composite structure, the three-layer composite structure includes a middle layer and skin layers arranged on both sides of the middle layer, one of the middle layer and the skin layer is the thermoplastic polyester elastomer film layer, and the other of the middle layer and the skin layer is the thermoplastic polyurethane elastomer film layer.

[0007] Optionally, the glass transition point of the thermoplastic polyester elastomer film layer is less than -20°C, and the melting point is greater than 190°C; and / or the stress retention rate of the thermoplastic polyester elastomer film layer is greater than or equal to 55%.

[0008] Optionally, the stress retention rate of the thermoplastic polyurethane elastomer film layer is greater than or equal to 75%; and / or the damping of the thermoplastic polyurethane elastomer film layer is greater than or equal to 0.15.

[0009] Optionally, the soft segments of the thermoplastic polyurethane elastomer film layer and the thermoplastic polyester elastomer film layer are both polyether polyols, the hard segment of the thermoplastic polyester elastomer film layer is polyester, and the hard segment of the thermoplastic polyurethane elastomer film layer is isocyanate.

[0010] Optionally, the hard segment of the thermoplastic polyurethane elastomer film layer includes aromatic isocyanate, and the aromatic isocyanate includes one of toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, and dimethyl diphenyl diisocyanate, and the soft segment of the thermoplastic polyurethane elastomer is polycarbonate polyol.

[0011] Optionally, the stress retention rate of the loudspeaker diaphragm is greater than or equal to 60%.

[0012] Optionally, the thickness of the loudspeaker diaphragm is 25 μm to 300 μm; and / or the thermoplastic polyurethane elastomer film layer accounts for 30% to 75% of the total thickness of the loudspeaker diaphragm.

[0013] According to a second aspect of the utility model, a sound-generating device is provided, which includes the loudspeaker diaphragm of the above embodiment.

[0014] According to a third aspect of the present invention, an electronic device is provided, which includes the sound generating device of the above embodiment.

[0015] A technical effect of the present application is that the speaker diaphragm includes a stacked thermoplastic polyurethane elastomer film layer and a thermoplastic polyester elastomer film layer, and the thickness of the thermoplastic polyurethane elastomer film layer in the speaker diaphragm accounts for no less than 30%. The speaker diaphragm of the utility model is composed of a stacked thermoplastic polyurethane elastomer film layer and a thermoplastic polyester elastomer film layer, so that it can have the advantages of both high damping and high and low temperature resistance, greatly improving the listening yield of the sound-emitting device using the speaker diaphragm of the utility model.

[0016] 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

[0017] 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.

[0018] Figure 1 It is a structural schematic diagram of a sound-generating device according to an embodiment of the utility model.

[0019] Figure 2 It is a structural schematic diagram of a loudspeaker diaphragm according to an embodiment of the utility model.

[0020] Figure 3 It is a structural schematic diagram of a loudspeaker diaphragm according to another embodiment of the utility model.

[0021] Figure 4It is a structural schematic diagram of a loudspeaker diaphragm according to another embodiment of the utility model.

[0022] Figure 5 It is the amplitude test curve of the speaker diaphragm in Example 2 and Comparative Examples 3 and 4 before waterproof reliability.

[0023] Figure 6 It is the amplitude test curve of the speaker diaphragm in Example 2 and Comparative Examples 3 and 4 after waterproof reliability.

[0024] Reference numerals:

[0025] 100, sound-generating device; 10, housing; 20, speaker diaphragm; 30, voice coil; 40, permanent magnet;

[0026] 21. Thermoplastic polyurethane elastomer film layer; 22. Thermoplastic polyester elastomer film layer. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0030] 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.

[0031] 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.

[0032] According to one embodiment of the present application, a speaker diaphragm 20 is provided. Figures 1 to 4As shown, the speaker diaphragm 20 includes a laminated thermoplastic polyurethane (TPU) film layer 21 and a thermoplastic polyester (TPEE) film layer 22. The thickness of the thermoplastic polyurethane film layer 21 in the speaker diaphragm 20 accounts for no less than 30%.

[0033] In one embodiment, the loudspeaker diaphragm 20 of the present invention is formed by a composite of a thermoplastic polyurethane elastomer film layer 21 and a thermoplastic polyester elastomer film layer 22. The thermoplastic polyurethane elastomer film layer 21 has good damping properties, the thermoplastic polyester elastomer film layer 22 has a low glass transition point, and the thermoplastic polyester elastomer film layer 22 has a high melting point. Therefore, the composite film formed by the composite of the thermoplastic polyurethane elastomer film layer 21 and the thermoplastic polyester elastomer film layer 22 can have the advantages of both high damping and high and low temperature resistance, greatly improving the listening yield of the sound-generating device 100 using the loudspeaker diaphragm 20 of the present invention.

[0034] In this embodiment, the thickness of the thermoplastic polyurethane elastomer film layer 21 in the speaker diaphragm 20 accounts for no less than 30%. By adjusting the thickness of the thermoplastic polyurethane elastomer film layer 21, the damping of the speaker diaphragm 20 can be adjusted.

[0035] In this example, the weight of the speaker diaphragm 20 can be adjusted by setting the thickness of the speaker diaphragm 20 and the thickness ratio of the thermoplastic polyurethane elastomer film layer 21 , so as to facilitate the lightweight design of the speaker diaphragm 20 .

[0036] In this example, when the thermoplastic polyurethane elastomer film layer 21 is a single layer, the single layer of thermoplastic polyurethane elastomer film layer 21 accounts for greater than or equal to 30%. When the thermoplastic polyurethane elastomer film layer 21 is a multi-layer, the total thickness of the multi-layer thermoplastic polyurethane elastomer film layer 21 accounts for greater than or equal to 30%.

[0037] The thickness of the loudspeaker diaphragm 20 may be 30 μm, 50 μm, 70 μm, 100 μm, 150 μm, 200 μm, 250 μm or 280 μm, etc. The thickness of the thermoplastic polyurethane elastomer film layer 21 in the loudspeaker diaphragm may account for 35%, 40%, 50%, 52%, 55%, 58%, 60% or 65%, etc. In the above value range, the loudspeaker diaphragm 20 can have a large damping.

[0038] In one embodiment, the speaker diaphragm 20 is formed into a two-layer composite structure, which includes a layer of the thermoplastic polyurethane elastomer film layer 21 and a layer of the thermoplastic polyester elastomer film layer 22. Alternatively, the speaker diaphragm 20 is formed into a three-layer composite structure, which includes an intermediate layer and skin layers disposed on both sides of the intermediate layer, one of the intermediate layer and the skin layer is the thermoplastic polyester elastomer film layer 22, and the other of the intermediate layer and the skin layer is the thermoplastic polyurethane elastomer film layer 21.

[0039] like Figure 2 As shown, the speaker diaphragm 20 is formed into a two-layer composite structure, and the two-layer composite structure includes a layer of the thermoplastic polyurethane elastomer 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 thermoplastic polyurethane elastomer 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.

[0040] like Figure 3 As shown, the thermoplastic polyurethane elastomer 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 thermoplastic polyurethane elastomer 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 thermoplastic polyurethane elastomer film layer 21 along the thickness direction. During preparation, the two layers of thermoplastic polyester elastomer layer 22 are bonded to the two sides of the thermoplastic polyurethane elastomer film layer 21. The two layers of thermoplastic polyester elastomer film layers 22 serve 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. The thermoplastic polyurethane elastomer film layer 21 as the middle layer can make the speaker diaphragm 20 have good damping properties.

[0041] like Figure 4 As shown, the thermoplastic polyurethane elastomer 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 thermoplastic polyurethane elastomer film layer 21 is the skin layer. The two layers of thermoplastic polyurethane elastomer film layers 21 are respectively bonded to the two sides of the thermoplastic polyester elastomer film layer 22 along the thickness direction. The thermoplastic polyurethane elastomer film layer 21 has good tensile strength and resilience, and can provide a high stress retention rate for the speaker diaphragm 20, so that the speaker diaphragm undergoes elastic deformation when subjected to external force and can return to a balanced state.

[0042] In one embodiment, the glass transition point of the thermoplastic polyester elastomer film layer 22 is less than -20°C and the melting point is greater than 190°C; and / or the stress retention rate of the thermoplastic polyester elastomer film layer 22 is greater than or equal to 55%.

[0043] In this embodiment, the glass transition point, i.e., the glass transition temperature (Tg), refers to the temperature at which the material changes from a liquid state or a high elastic state at high temperature to a high elastic state at low temperature, i.e., a glass state. That is, when the temperature is higher than the glass transition point, for example, the thermoplastic polyester elastomer film layer 22 is in a high elastic state. In the high elastic state, the thermoplastic polyester elastomer film layer 22 has high elasticity. When the temperature is lower than the glass transition temperature, the thermoplastic polyester elastomer film layer 22 is in a glass state. In the glass state, the thermoplastic polyester elastomer film layer 22 has low elasticity and high hardness. The glass transition point of the thermoplastic polyester elastomer film layer 22 is less than -20°C, which enables the thermoplastic polyester elastomer film layer 22 to maintain a high elastic state at a normal use temperature, thereby making the speaker diaphragm 20 have a high elasticity. The thermoplastic polyester elastomer film layer 22 maintains a stable state, i.e., a glass state or a high elastic state, at room temperature or low temperature, and the phenomenon of the thermoplastic polyester elastomer film layer 22 changing between the glass state and the high elastic state does not occur. Since the elasticity of the speaker diaphragm 20 changes during the transformation process, the vibration amplitude of the speaker diaphragm 20 changes, and the sound effect is unstable. Furthermore, the glass transition point of the thermoplastic polyester elastomer film layer 22 is less than -40°C. The sound-generating device 100 using the speaker diaphragm 20 of the present invention can meet the use requirements of various environments. The speaker diaphragm 20 can meet the requirements of continuous vibration at -40°C without breaking, and does not deform when vibrating at high temperature continuously.

[0044] In this embodiment, the melting point of the thermoplastic polyester elastomer film layer 22 is greater than 190°C. When the melting point of the diaphragm is low, the high temperature resistance of the diaphragm is poor. At high temperatures, the diaphragm will soften and the vibration effect will deteriorate, resulting in a poor listening yield of the sound-generating device. The melting point of the thermoplastic polyester elastomer film layer 22 of the present invention is greater than 190°C, so that the thermoplastic polyester elastomer film layer 22 can support the entire speaker diaphragm 20 at high temperatures, thereby improving the high temperature resistance of the speaker diaphragm 20. At high temperatures, the speaker diaphragm 20 of the present invention also has a higher listening yield.

[0045] In this embodiment, the stress retention rate of the thermoplastic polyester elastomer film layer 22 is greater than or equal to 55%. For example, the stress retention rate of the thermoplastic polyester elastomer film layer 22 may be 58%, 60%, 65% or 68%, etc. By limiting the stress retention rate of the thermoplastic polyester elastomer film layer 22 to the above value range, the resilience of the speaker diaphragm 20 can meet the use requirements.

[0046] In one embodiment, the stress retention rate of the thermoplastic polyurethane elastomer film layer 21 is greater than or equal to 75%; and / or the damping of the thermoplastic polyurethane elastomer film layer 21 is greater than or equal to 0.15.

[0047] In this embodiment, the stress retention rate of the thermoplastic polyurethane elastomer film layer 21 is greater than or equal to 75%. The thermoplastic polyurethane elastomer film layer 21 and the thermoplastic polyester elastomer film layer 22 are stacked to form a speaker diaphragm 20. The speaker diaphragm 20 of the present invention can have a large stress retention rate and excellent deformation recovery ability under high pressure. For example, the stress retention rate of the thermoplastic polyurethane elastomer film layer 21 can be 78%, 80%, 85% or 88%, etc.

[0048] In this embodiment, the damping of the thermoplastic polyurethane elastomer film layer 21 is greater than or equal to 0.15. The speaker diaphragm 20 includes a stacked thermoplastic polyurethane elastomer film layer 21 and a thermoplastic polyester elastomer film layer 22. The damping of the thermoplastic polyurethane elastomer film layer 21 at room temperature is not less than 0.15, so that the speaker diaphragm 20 can have a higher damping, so that the sound-generating device 100 using the speaker diaphragm 20 of the present invention has a higher listening yield.

[0049] In the embodiment of the present invention, the damping of the thermoplastic polyurethane elastomer film layer 21 at room temperature is not less than 0.15, which makes the overall damping of the loudspeaker diaphragm 20 high and effectively suppresses the polarization phenomenon of the loudspeaker diaphragm 20 during vibration.

[0050] Furthermore, the damping of the thermoplastic polyurethane elastomer film layer 21 at room temperature is not less than 0.2, which can make the damping of the speaker diaphragm 20 at room temperature high, and the sound-generating device using the speaker diaphragm 20 of the present invention has a better listening experience and less polarization. For example, the damping of the thermoplastic polyurethane elastomer film layer 21 at room temperature can also be 0.25, 0.27, 0.30 or 0.35, etc. The above-mentioned damping value range of the thermoplastic polyurethane elastomer film layer 21 can provide a higher damping for the speaker diaphragm 20.

[0051] It should be noted that 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.

[0052] The stress retention rate is tested by dynamic mechanical analysis (DMA) at room temperature, a strain of 5%, a holding time of 5 minutes, a relaxation time of 10 minutes, and the highest point of the relaxation stress is taken as E1, and the stress after 10 minutes of relaxation is taken as E2.

[0053] Stress retention rate = E2 / E1*100%.

[0054] In one embodiment, the soft segments of the thermoplastic polyurethane elastomer film layer and the thermoplastic polyester elastomer film layer are both polyether polyols, the hard segment of the thermoplastic polyester elastomer film layer is polyester, and the hard segment of the thermoplastic polyurethane elastomer film layer is isocyanate.

[0055] In this example, the soft segments of the thermoplastic polyurethane elastomer film layer 21 and the thermoplastic polyester elastomer film layer 22 are both polyether polyols, that is, the thermoplastic polyurethane elastomer film layer 21 in the present invention is polyether TPU, and the thermoplastic polyester elastomer film layer 22 in the present invention is polyether TPEE. Polyether polyols are usually obtained by reacting epoxy compounds, thiols or hydroxymethyltriphenylphosphine. Through different reaction conditions, the molecular weight and molecular structure of polyether polyols can be controlled. Polyether polyols have good flexibility, so that they can provide flexibility for the plastic polyurethane elastomer film layer 21 and the thermoplastic polyester elastomer film layer 22, so that the speaker diaphragm 20 has good low temperature resistance and is not easy to break when working at -20°C. Moreover, the thermoplastic polyester elastomer has good high temperature resistance. By compounding a thermoplastic polyurethane elastomer film layer 21 and a thermoplastic polyester elastomer film layer 22 both of which use polyether polyol soft segments, high resilience and high temperature resistance can be taken into account. The speaker diaphragm 20 of the present application can not only work normally under high temperature conditions, but also has good deformation recovery ability under high pressure conditions.

[0056] In this embodiment, in this example, the polyester hard segment of the thermoplastic polyester elastomer film layer 22 can provide rigidity to the thermoplastic polyester elastomer film layer 22, and the isocyanate hard segment of the thermoplastic polyurethane elastomer film layer 21 can provide rigidity to the thermoplastic polyurethane elastomer film layer 21. The strength of the thermoplastic polyester elastomer film layer 22 and the thermoplastic polyurethane elastomer film layer 21 is improved, thereby improving the strength of the speaker diaphragm 20.

[0057] In this example, the thermoplastic polyester elastomer film layer 22 and the thermoplastic polyurethane elastomer film layer 21 are materials with soft and hard segments combined with microphase separation. The soft segment can provide flexibility to the film layer, and the hard segment can provide rigidity to the film layer, thereby ensuring that the speaker diaphragm 20 has good flexibility and high strength.

[0058] In one embodiment, the thermoplastic polyester elastomer film layer 22 is prepared from a thermoplastic polyester elastomer. Thermoplastic polyester elastomer is a block copolymer, which is usually composed of a polyester hard segment and a polyether or aliphatic polyester soft segment. Optionally, 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 the density of the thermoplastic polyurethane elastomer 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 present invention has a larger amplitude, and the sound-generating device using the speaker diaphragm 20 has a greater mid-frequency loudness.

[0059] In one embodiment, the hard segment of the thermoplastic polyurethane elastomer film layer 21 includes aromatic isocyanate, and the aromatic isocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, and dimethyl diphenyl diisocyanate. The soft segment of the thermoplastic polyurethane elastomer is polycarbonate polyol.

[0060] In this embodiment, aromatic isocyanate refers to an isocyanate containing a benzene ring structure in the molecular formula. The presence of the benzene ring can provide certain molecular structure damping and rigidity.

[0061] The following is a comparison of the tensile modulus and tensile strength of aliphatic TPU and aromatic TPU, as shown in Table 2. Among them, aliphatic TPU and aromatic TPU are TPUs with the same soft segment, that is, the soft segment is polycarbonate polyol, aliphatic TPU uses isophordione diisocyanate as the hard segment, aromatic TPU uses toluene diisocyanate as the hard segment, and the mass fraction of the hard segment of the two TPUs is 18wt% of the mass fraction of TPU.

[0062] Table 1 - Comparison of tensile modulus and tensile strength of aliphatic TPU and aromatic TPU

[0063] Material Tensile modulus / MPa Tensile strength / MPa Aliphatic TPU 10 13 Aromatic TPU 20 20

[0064] According to Table 1 above, the tensile modulus and tensile strength of aromatic TPU are greater, so that the speaker diaphragm 20 prepared using aromatic TPU can be made stronger and less likely to break.

[0065] In this embodiment, the polycarbonate polyol molecular formula is:

[0066]

[0067] Wherein, n represents a natural number; O-CO-O represents a carbonate group; R represents a hydrocarbon chain or a carbon ring chain; -OH is the terminal hydroxyl group of the polyol, and -OH has good activity and can undergo polymerization reaction with isocyanate.

[0068] The main chain of the polycarbonate polyol molecule is composed of carbonate groups, which have extremely high chemical corrosion resistance and mechanical strength, and can meet the application requirements in different environments. The side chain of the polycarbonate polyol molecule is composed of hydrocarbon chains or carbon ring chains. The hydrocarbon chains or carbon ring chains have high rigidity and stability, which can ensure the mechanical properties and chemical stability of the thermoplastic polyurethane elastomer film layer 21.

[0069] Thermoplastic polyurethane elastomers prepared using polyether polyols have better hydrolysis resistance, allowing them to remain stable for a long time in a humid or underwater environment and have good low-temperature performance. Thermoplastic polyurethane elastomers prepared using polyester polyols have certain improvements in oil resistance and temperature resistance. Thermoplastic polyurethane elastomers prepared using carbonate polyester polyols have high oil resistance and high temperature resistance, high damping at room temperature, and the thermoplastic polyurethane elastomer film layer 21 prepared from thermoplastic polyurethane elastomer has good high-temperature stability, high mechanical strength, and excellent chemical resistance. Thermoplastic polyurethane elastomer film layer 21 can be used at high temperatures, is not prone to deformation, aging and other problems, can withstand greater stress and strain, and can also withstand corrosion from a variety of chemical substances, including oleic acid, grease, etc., thereby improving the high-temperature stability, mechanical strength and chemical resistance of the speaker diaphragm 20 of the present invention.

[0070] In one example, the stress retention rate of the speaker diaphragm 20 is greater than or equal to 60%. The speaker diaphragm 20 has a large stress retention rate, so that the stress relaxation of the speaker diaphragm 20 is small, and the deformation recovery ability under high pressure is better. For example, after high waterproofing (for example, after waterproofing 10 meters underwater), the speaker diaphragm 20 can return to a balanced state after being squeezed and deformed by water pressure, so as to ensure that the sound-generating device 100 using the speaker diaphragm 20 of the present invention has good listening quality.

[0071] Furthermore, the stress retention rate of the speaker diaphragm 20 may be greater than or equal to 70%. For example, the stress retention rate of the speaker diaphragm 20 may be 71%, 72%, 77% or 81%, etc. The stress retention rate of the speaker diaphragm 20 is limited to the above value range so that the speaker diaphragm 20 can meet the high waterproof use requirements.

[0072] In one embodiment, the thickness of the loudspeaker diaphragm 20 is 25 μm to 300 μm; and / or the thermoplastic polyurethane elastomer film layer 21 accounts for 30% to 75% of the total thickness of the loudspeaker diaphragm.

[0073] In this example, the stress retention rate of the thermoplastic polyurethane elastomer film layer 21 is relatively large, and the thermoplastic polyurethane elastomer film layer 21 is set to account for 30% to 75% of the total thickness of the speaker diaphragm. So that the stress retention rate of the speaker diaphragm 20 can be greater than or equal to 60%. The thermoplastic polyester elastomer film layer 22 has good high temperature resistance. At high temperatures, the thermoplastic polyester elastomer film layer 22 still has a high modulus and can provide a certain support at high temperatures above 150°C, so that the speaker diaphragm 20 is not easily deformed. Therefore, by limiting the thickness ratio of the thermoplastic polyurethane elastomer film layer 21 and the thermoplastic polyester elastomer film layer 22, the speaker diaphragm 20 can have a higher stress retention rate and better high temperature resistance.

[0074] In this example, the weight of the speaker diaphragm 20 can be adjusted by setting the thickness of the speaker diaphragm 20 and the thickness ratio of the thermoplastic polyurethane elastomer film layer 21 , so as to facilitate the lightweight design of the speaker diaphragm 20 .

[0075] In this example, when the thermoplastic polyurethane elastomer film layer 21 is a single layer, the single layer of thermoplastic polyurethane elastomer film layer 21 accounts for 30% to 75%. When the thermoplastic polyurethane elastomer film layer 21 is a multi-layer, the total thickness of the multi-layer thermoplastic polyurethane elastomer film layer 21 accounts for 30% to 75%.

[0076] The thickness of the speaker diaphragm 20 may be 35 μm, 40 μm, 60 μm, 110 μm, 140 μm, 190 μm, 240 μm or 270 μm, etc. The thickness of the thermoplastic polyurethane elastomer film layer 21 in the speaker diaphragm may account for 36%, 48%, 55%, 52%, 56%, 59%, 63% or 65%, etc. In the above value range, the speaker diaphragm 20 can have a large stress retention rate.

[0077] In one example, the speaker diaphragm 20 contains an antioxidant, and the antioxidant includes at least one of antioxidant 1010, antioxidant 2, antioxidant 6, antioxidant 4, antioxidant 1076, antioxidant 168, antioxidant BLE, antioxidant 4010, antioxidant 4010NA, antioxidant 4020, antioxidant 4030, and antioxidant 4040.

[0078] In this example, the speaker diaphragm 20 can achieve the effect of extending the service life by adding an antioxidant. The antioxidant can be added to the raw material of the thermoplastic polyurethane elastomer film layer 21, or the antioxidant can also be added to the raw material of the thermoplastic polyester elastomer film layer 22, or the antioxidant can be added to the raw materials of both the thermoplastic polyurethane elastomer film layer 21 and the thermoplastic polyester elastomer film layer 22.

[0079] In this example, the antioxidant accounts for 0.2wt% to 5wt% by mass in the speaker diaphragm. If the amount of antioxidant added is too little, the service life cannot be extended. If too much antioxidant is added, the antioxidant cannot be well soluble in the matrix material and is difficult to disperse evenly, resulting in a decrease in the mechanical properties of the material, and it is easy to precipitate to the surface over time. Furthermore, the amount of antioxidant added can be 0.25wt% to 3wt%. For example, the amount added can be 0.5wt%, 1wt%, 1.5wt%, 2wt% or 2.5wt%, etc. The use of antioxidants in the above range of values ​​can play a good role in extending the service life.

[0080] In one example, the speaker diaphragm 20 further contains at least one of a colorant, a filler, a plasticizer, an anti-ultraviolet additive, an antistatic agent, and a processing aid.

[0081] Take carbon black as an example to explain the filler. Carbon black is an amorphous structure, and the particles form aggregates through physical and chemical bonding with each other. The primary structure of carbon black is composed of aggregates. At the same time, there are van der Waals forces or hydrogen bonds between the aggregates, which can aggregate into a spatial network structure, which is the secondary structure of carbon black. The surface of carbon black has hydrogen, carboxyl, lactone, free radicals, quinone and other groups that can undergo substitution, reduction, oxidation reactions, etc. When carbon black is added to a thermoplastic polyester elastomer, due to the strong interaction between the surface of carbon black and the interface of the thermoplastic polyester elastomer, when the material is subjected to force, the molecular chain is easier to slide on the surface of carbon black, but it is not easy to separate from the carbon black. The thermoplastic polyester elastomer and carbon black form a strong bond that can slide, and the mechanical strength is increased.

[0082] The dye can dye the thermoplastic polyester elastomer film layer 22 or the thermoplastic polyurethane elastomer film layer 21. The polarity of the thermoplastic polyester elastomer film layer 22 and the thermoplastic polyurethane elastomer film layer 21 is relatively strong, and both are relatively easy to make into different colors by adding dyes to increase the aesthetics. In addition to being used as a filler, carbon black can also be used as a dye to dye the speaker diaphragm 20 black or gray. By adding different additives, the film layer can have different functions. For example, since the thermoplastic polyester elastomer film layer 22 will degrade under ultraviolet radiation, by adding ultraviolet absorbers, the thermoplastic polyester elastomer film layer 22 can have ultraviolet absorption function. Antistatic additives and processing aids can improve process problems in the processing process, improve the stability of the cast film, and reduce the stickiness of the surface of the thermoplastic polyurethane elastomer after film formation.

[0083] The speaker diaphragm 20 of the present invention is described in detail below with reference to specific embodiments and comparative examples. It should be understood that the following description is merely exemplary and is not a specific limitation to the present invention.

[0084] Embodiment 1:

[0085] The speaker diaphragm 20 of the present invention comprises a layer of thermoplastic polyurethane elastomer film layer 21 and a layer of thermoplastic polyester elastomer film layer 22 which are stacked. The soft segment in the thermoplastic polyurethane elastomer film layer 21 is polycarbonate polyol, the damping of the thermoplastic polyurethane elastomer film layer 21 is 0.19, the thickness of the thermoplastic polyurethane elastomer film layer 21 is 43 μm, the thickness of the thermoplastic polyurethane elastomer film layer 21 accounts for about 71.4%, the thickness of the thermoplastic polyester elastomer film layer 22 is 19 μm, the glass transition point of the thermoplastic polyester elastomer film layer 22 is -27°C, the melting point is 208°C, and the damping is 0.05. The damping of the speaker diaphragm 20 is 0.14.

[0086] Comparative Example 1:

[0087] A single-layer thermoplastic polyurethane elastomer film layer 21 is used as a diaphragm, with a thickness of 68 μm and a damping of 0.19, wherein the thermoplastic polyurethane elastomer in Comparative Example 1 is of the same material type as the thermoplastic polyurethane elastomer in Example 1. The outer dimensions of the speaker diaphragm 20 are consistent with those of the speaker diaphragm 20 in Example 1.

[0088] Comparative Example 2:

[0089] A single-layer thermoplastic polyester elastomer film layer 22 is used as the diaphragm, with a thickness of 45 μm, a glass transition temperature of -27°C, a melting point of 208°C, and a damping of 0.05. The thermoplastic polyester elastomer in Comparative Example 2 is of the same material type as the thermoplastic polyester elastomer in Example 1. The outer dimensions of the speaker diaphragm 20 are consistent with those of the speaker diaphragm 20 in Example 1.

[0090] Table 2 - Listening yield of the loudspeaker diaphragm 20 of Example 1 and Comparative Examples 1 and 2

[0091] F0 Listening yield / % High temperature reliability listening yield / % Example 1 621 96 97 Comparative Example 1 617 97 61 Comparative Example 2 624 39 32

[0092] According to Table 2, the F0 of Example 1 is similar to that of Comparative Example 1 and Comparative Example 2, that is, the different thicknesses of the speaker diaphragm 20 are set to make the F0 of Example 1 similar to that of Comparative Example 1 and Comparative Example 2. According to the comparison between Example 1 and Comparative Example 1, the thermoplastic polyurethane elastomer film layer 21 has higher damping, so that the listening yield of the speaker diaphragm 20 of Example 1 is higher. However, the single-layer thermoplastic polyurethane elastomer film layer 21 will undergo certain deformation after high temperature, and the listening yield of the speaker diaphragm 20 of Comparative Example 1 decreases after high temperature reliability.

[0093] According to the comparison between Example 1 and Comparative Example 2, it can be seen that since the damping of the single-layer thermoplastic polyester elastomer film layer 22 of Comparative Example 2 is relatively low, the listening yield is very low. However, since the damping effect of the thermoplastic polyurethane elastomer film layer 21 of the speaker diaphragm 20 of Example 1 is good, the thermoplastic polyester elastomer film layer 22 has excellent temperature resistance and strong supporting ability under high temperature, the speaker diaphragm 20 of Example 1 has good high-temperature reliability and the subsequent listening yield changes little.

[0094] Therefore, the speaker diaphragm 20 of Example 1 of the present invention has good damping effect and good high temperature resistance by reasonably matching the thickness of the thermoplastic polyurethane elastomer film layer 21 and the thermoplastic polyester elastomer film layer 22, and has good listening yield before and after high temperature reliability.

[0095] The test method of the listening yield rate is as follows: the sound-generating device 100 of the embodiment 1 and the comparative examples 1 and 2 of the present invention is placed in a room temperature environment, and then a power-on test is performed, with a voltage of 1.8V and a time of 196 hours. After taking out, the acoustic performance of the sound-generating device 100 is tested. 100 sound-generating devices 100 are taken and tested. The listening yield rate is the percentage of the number of sound-generating devices 100 that pass the test to the total number of sound-generating devices 100.

[0096] The test method of the listening yield rate after high temperature reliability is as follows: the sound-generating device 100 using the embodiment 1 of the present invention and the comparative examples 1 and 2 is placed in a 120°C environment, and then a power-on test is performed, with a voltage of 1.8V and a time of 196 hours. After taking out, the acoustic performance of the sound-generating device 100 is tested. 100 sound-generating devices 100 are taken for testing. The listening yield rate is the percentage of the number of sound-generating devices 100 that pass the test to the total number of sound-generating devices 100.

[0097] Embodiment 2:

[0098] The speaker diaphragm 20 includes two layers of polyether TPEE and one layer of polyether TPU. The polyether TPEE is the epidermis and the polyether TPU is the middle layer. The total thickness of the speaker diaphragm is 50 μm, of which the thickness of the polyether TPU accounts for 60%. The stress retention rate of the polyether TPEE is 61%, the stress retention rate of the polyether TPU is 85%, and the overall stress retention rate of the speaker diaphragm 20 is 71%.

[0099] Comparative Example 3:

[0100] The loudspeaker diaphragm 20 is a single-layer polyether TPEE with a total thickness of 50 μm and a stress retention rate of 61%. The outer dimensions of the loudspeaker diaphragm 20 are consistent with those of the loudspeaker diaphragm 20 of the second embodiment.

[0101] Comparative Example 4:

[0102] The loudspeaker diaphragm 20 is a single-layer polyether TPU with a total thickness of 50 μm and a stress retention rate of 85%. The outer dimensions of the loudspeaker diaphragm 20 are consistent with those of the loudspeaker diaphragm 20 of the second embodiment.

[0103] The length of the loudspeaker diaphragm in the above-mentioned embodiment 2 and comparative examples 3 and 4 is about 17 mm, and the width is about 12 mm. In addition, 100 samples are selected for the film breakage rate test in both the embodiment 2 and comparative examples 3 and 4.

[0104] The test method for stress retention rate is as follows: according to ASTM D5026-15 standard, the sample is kept at 23°C for 5 minutes, the instantaneous tensile strain is 10%, the sample is relaxed for 10 minutes, and the sample is restored for 5 minutes. The maximum stress and the minimum stress on the curve are taken, and the stress retention rate of the sample is the ratio of the minimum stress to the maximum stress.

[0105] Table 3 - Film breakage rate of the loudspeaker diaphragm 20 in Example 2 and Comparative Examples 3 and 4

[0106] Film breakage rate after low temperature reliability / % Film breakage rate after high temperature reliability / % Example 2 0 1 Comparative Example 3 0 2 Comparative Example 4 0 85

[0107] As shown in Table 3 above, the film breakage rate of the speaker diaphragms in Example 2 of the present invention and Comparative Examples 3 and 4 after low-temperature reliability is 0. It can be seen that the speaker diaphragm of Example 2 of the present invention has good low-temperature resistance. However, the film breakage rate of the speaker diaphragm of Example 2 of the present invention after high-temperature reliability is less than that of the speaker diaphragms in Comparative Examples 3 and 4 after high-temperature reliability.

[0108] The test conditions for the film breakage rate after low-temperature reliability are: 1.4V voltage, -20°C environment, and the sound device 100 works for 24 hours. The test conditions for the film breakage rate after high-temperature reliability are: 0.8V voltage, 150°C environment, and the sound device 100 works for 10 hours.

[0109] like Figure 5 and Figure 6 As shown, Figure 5 It is the amplitude test curve of the speaker diaphragm in Example 2 and Comparative Examples 3 and 4 before waterproof reliability. Figure 6 The amplitude test curves of the loudspeaker diaphragms after waterproof reliability in Example 2 and Comparative Examples 3 and 4 are shown in FIG. 1 , wherein the horizontal axis represents the frequency, in Hz, and the vertical axis represents the amplitude, in μm.

[0110] like Figure 5 and Figure 6 As shown, the amplitude curves of the speaker diaphragms of Example 2 and Comparative Examples 3 and 4 are compared. The amplitude curves of Comparative Example 4 and Example 2 have high symmetry and no peaks, indicating that the polyether TPU has good resistance to deformation, that is, the polyether TPU can have a high stress retention rate, so that the speaker diaphragm 20 can return to a balanced state after being deformed by pressure. However, the polyether TPEE of Comparative Example 3 has a large deformation under high water pressure, the shape of the speaker diaphragm changes, the amplitude has a peak, and the symmetry is poor, which is prone to failure.

[0111] The waterproof reliability test conditions are as follows: the speaker diaphragm 20 is placed in a specific waterproof tooling under a water pressure of 10 m for 1 hour, and then the amplitude of the sound-generating device 100 using the speaker diaphragm 20 is taken out and tested.

[0112] The speaker diaphragm 20 in this embodiment includes a thermoplastic polyurethane elastomer film layer and a thermoplastic polyester elastomer film layer which are stacked, and the soft segments of the thermoplastic polyurethane elastomer film layer and the thermoplastic polyester elastomer film layer are both polyether polyols. The stress retention rate of the thermoplastic polyester elastomer film layer is greater than or equal to 55%, and the stress retention rate of the thermoplastic polyurethane elastomer film layer is greater than or equal to 75%. Therefore, both high resilience and high temperature resistance can be taken into account, and the diaphragm can not only work normally under high temperature conditions, but also has good deformation recovery ability under high pressure conditions.

[0113] According to another embodiment of the present invention, a method for preparing the loudspeaker diaphragm 20 of the above embodiment is provided. The method comprises preparing the loudspeaker diaphragm 20 by a multi-layer co-extrusion process or a multi-extrusion process.

[0114] In this embodiment, the multi-layer co-extrusion process can extrude more than two layers of multi-layer composite films at the same time, and the multi-layer composite films can be made of the same material or different materials. The speaker diaphragm 20 of the utility model can be a structure of a layer of thermoplastic polyester elastomer film layer 22 and a layer of thermoplastic polyurethane elastomer film layer 21, or two layers of thermoplastic polyester elastomer film layers 22 and a layer of thermoplastic polyurethane elastomer film layer 21. Therefore, the multi-layer co-extrusion process can complete the co-extrusion of the multi-layer film, thereby improving the processing efficiency.

[0115] In this embodiment, the multiple extrusion process is to first prepare a film, and then cast another film on it. The multiple extrusion process can form films, and the thickness of two or more films can be controlled very accurately, and the thickness accuracy of the film layer can be improved. When the material quality is poor, it can also be more accurately analyzed which film layer in the speaker diaphragm 20 has a problem.

[0116] According to another embodiment of the present invention, a sound generating device is provided. Figure 1 As shown, the sound-generating device 100 includes the speaker diaphragm 20 of the above embodiment.

[0117] In this embodiment, the speaker diaphragm 20 includes a laminated thermoplastic polyurethane elastomer film layer 21 and a thermoplastic polyester elastomer film layer 22. The damping of the thermoplastic polyurethane elastomer film layer 21 at room temperature is not less than 0.15, so that the speaker diaphragm 20 can have a higher damping, so that the sound-generating device 100 using the speaker diaphragm 20 of the utility model has a higher listening yield.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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: A thermoplastic polyurethane elastomer film layer and a thermoplastic polyester elastomer film layer are stacked, and the thickness of the thermoplastic polyurethane elastomer film layer in the loudspeaker diaphragm accounts for no less than 30%.

2. The loudspeaker diaphragm according to claim 1, characterized in that: The loudspeaker diaphragm is formed into a two-layer composite structure, and the two-layer composite structure includes a layer of the thermoplastic polyurethane elastomer film layer and a layer of the thermoplastic polyester elastomer film layer; Alternatively, the speaker diaphragm is formed as a three-layer composite structure, which includes a middle layer and skin layers arranged on both sides of the middle layer, one of the middle layer and the skin layer is the thermoplastic polyester elastomer film layer, and the other of the middle layer and the skin layer is the thermoplastic polyurethane elastomer film layer.

3. The loudspeaker diaphragm according to claim 1, characterized in that: The glass transition point of the thermoplastic polyester elastomer film layer is less than -20°C and the melting point is greater than 190°C; And / or, the stress retention rate of the thermoplastic polyester elastomer film layer is greater than or equal to 55%.

4. The loudspeaker diaphragm according to claim 1, characterized in that: The stress retention rate of the thermoplastic polyurethane elastomer film layer is greater than or equal to 75%; And / or, the damping of the thermoplastic polyurethane elastomer film layer is greater than or equal to 0.

15.

5. The loudspeaker diaphragm according to claim 1, characterized in that: The soft segments of the thermoplastic polyurethane elastomer film layer and the thermoplastic polyester elastomer film layer are both polyether polyols, the hard segment of the thermoplastic polyester elastomer film layer is polyester, and the hard segment of the thermoplastic polyurethane elastomer film layer is isocyanate.

6. The loudspeaker diaphragm according to claim 1, characterized in that: The hard segment of the thermoplastic polyurethane elastomer film layer includes aromatic isocyanate, which includes one of toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, and dimethyl diphenyl diisocyanate. The soft segment of the thermoplastic polyurethane elastomer is polycarbonate polyol.

7. The loudspeaker diaphragm according to claim 1, characterized in that: The stress retention rate of the loudspeaker diaphragm is greater than or equal to 60%.

8. The loudspeaker diaphragm according to claim 1, characterized in that: The thickness of the loudspeaker diaphragm is 25 μm to 300 μm; And / or, the thermoplastic polyurethane elastomer film layer accounts for 30% to 75% of the total thickness of the speaker diaphragm.

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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