Diaphragm for sound production device, sound production device, and electronic device

Abstract

The utility model discloses a diaphragm for sounding device, sounding device and electronic equipment. The diaphragm includes at least one thermoplastic polyurethane elastomer alloy layer, and the thermoplastic polyurethane elastomer alloy layer includes first thermoplastic polyurethane elastomer and second thermoplastic polyurethane elastomer. The glass transition temperature of the first thermoplastic polyurethane elastomer is -60 to -30 DEG C, and the glass transition temperature of the second thermoplastic polyurethane elastomer is -25 to 10 DEG C. The thermoplastic polyurethane elastomer alloy layer of the utility model includes thermoplastic polyurethane elastomer of different glass transition temperatures, can effectively expand the damping temperature zone of diaphragm, and diaphragm can keep good damping under the condition of wider frequency interval in the wider use temperature range.

Description

Technical Field

[0001] This utility model relates to the field of electroacoustic conversion technology, and more specifically, to a diaphragm for a sound-generating device, a sound-generating device, and an electronic device. Background Technology

[0002] In related technologies, existing VR products, AR products, smart glasses, and headphone speaker diaphragms typically use thermoplastic polyurethane elastomer (TPU) materials. TPU materials have excellent mechanical properties, a wide service temperature range, easy processability, and low processing costs.

[0003] However, existing TPU materials have low damping. In order to improve the damping of the diaphragm, the modulus change rate of the diaphragm will increase, which will lead to a decrease in F0 stability. Utility Model Content

[0004] One objective of this invention is to provide a new technical solution for a diaphragm in a sound-generating device.

[0005] According to a first aspect of the present invention, a diaphragm for a sound-generating device is provided. The diaphragm comprises at least one thermoplastic polyurethane elastomer alloy layer, the thermoplastic polyurethane elastomer alloy layer comprising a first thermoplastic polyurethane elastomer and a second thermoplastic polyurethane elastomer, the thickness of the thermoplastic polyurethane elastomer alloy layer being 10 μm-150 μm, and the thermoplastic polyurethane elastomer alloy layer having a first glass transition temperature and a second glass transition temperature, the first glass transition temperature being -60°C to -30°C, and the second glass transition temperature being -25°C to 10°C.

[0006] Optionally, the soft segment of the first thermoplastic polyurethane elastomer includes one of polycaprolactone, polybutylene adipate, polytetrahydrofuran, polyethylene oxide, polypropylene oxide, and copolyether.

[0007] Optionally, the soft segment of the second thermoplastic polyurethane elastomer includes one of polyethylene adipate, butanediol-based polycarbonate, hexanediol-based polycarbonate, 2-methyl-1,3-propanediol-based polycarbonate, copolycarbonate, and copolyester.

[0008] Optionally, the Young's modulus of the thermoplastic polyurethane elastomer alloy layer is 5 MPa-200 MPa;

[0009] And / or, the 5-minute creep recovery rate of the thermoplastic polyurethane elastomer alloy layer is 60%-98%.

[0010] Optionally, the density of the thermoplastic polyurethane elastomer alloy layer is 1.10 g / cm³. 3 -1.30g / cm3 .

[0011] Optionally, the hardness of the thermoplastic polyurethane elastomer alloy layer is 80A-93A.

[0012] Optionally, the Young's modulus of the thermoplastic polyurethane elastomer alloy layer decreases by ≤50% after heat treatment at 130°C for 90s-300s.

[0013] And / or, the Young's modulus change rate of the thermoplastic polyurethane elastomer alloy layer after heat treatment at 130°C for 90s-300s followed by constant humid heat treatment at 85°C, 85%RH, and 96h is ≤50%.

[0014] Optionally, the diaphragm is formed as a single-layer structure, and the diaphragm is composed of a single layer of the thermoplastic polyurethane elastomer alloy;

[0015] Alternatively, the diaphragm may be formed as a multilayer structure, comprising at least one thermoplastic polyurethane elastomer alloy layer and a composite layer, wherein the composite layer is stacked with the thermoplastic polyurethane elastomer alloy layer, and the composite layer is at least one of an elastomer layer, an engineering plastic layer, and a film layer.

[0016] According to a second aspect of the present invention, a sound-generating device is provided. This sound-generating device includes the diaphragm described in the present invention.

[0017] According to a third aspect of the present invention, an electronic device is provided. This electronic device includes the sound-generating device described in the present invention.

[0018] In this embodiment of the invention, the diaphragm includes at least one layer of thermoplastic polyurethane elastomer alloy; since the thermoplastic polyurethane elastomer alloy layer includes thermoplastic polyurethane elastomers with different glass transition temperatures, it can effectively expand the damping temperature range of the diaphragm, and the diaphragm can maintain good damping stability in a wider operating temperature range and a wider frequency range.

[0019] Other features and advantages of the present invention will become clear from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. Attached Figure Description

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

[0021] Figure 1 This is a cross-sectional view of the diaphragm according to an embodiment of the present invention.

[0022] Figure 2This is a perspective view of a sound-generating device according to an embodiment of the present utility model.

[0023] Figure 3 This is a cross-sectional view of a sound-generating device according to an embodiment of the present utility model.

[0024] Figure 4 This is a curve showing the six-point amplitude variation of the diaphragm with frequency in an embodiment of this utility model.

[0025] Figure 5 This is a curve showing the six-point amplitude of a proportional diaphragm as a function of frequency.

[0026] Figure label:

[0027] 100. Sound-generating device; 10. Housing; 20. Diaphragm; 30. Voice coil; 40. Permanent magnet. Detailed Implementation

[0028] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention.

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

[0030] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0031] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0033] The diaphragm 20 for a sound-generating device according to an embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0034] According to one embodiment of the present invention, a diaphragm 20 for a sound-generating device is provided. The diaphragm includes at least one thermoplastic polyurethane elastomer alloy layer, the thermoplastic polyurethane elastomer alloy layer comprising a first thermoplastic polyurethane elastomer and a second thermoplastic polyurethane elastomer, the thickness of the thermoplastic polyurethane elastomer alloy layer being 10 μm-150 μm, and the thermoplastic polyurethane elastomer alloy layer having a first glass transition temperature and a second glass transition temperature, the first glass transition temperature being -60°C to -30°C, and the second glass transition temperature being -25°C to 10°C.

[0035] Specifically, the diaphragm 20 is used in a sound-generating device, such as a miniature sound-generating device. The diaphragm 20 is part of a vibration system. The diaphragm 20 can be a folded ring diaphragm or a planar diaphragm. Optionally, the diaphragm 20 includes a thermoplastic polyurethane elastomer alloy layer. The thermoplastic polyurethane elastomer alloy layer can be one or more layers. The thermoplastic polyurethane elastomer alloy layer can be formed, for example, by compression molding, air compression molding, etc.

[0036] Thermoplastic polyurethane elastomer (TPU) is an elastomer copolymerized from soft and hard segments. The hard segments are formed by reacting diisocyanate and a chain extender. The range of selectable soft segments is as described below. The thermoplastic polyurethane elastomer alloy layer comprises two thermoplastic polyurethane elastomers with different glass transition temperatures: a first thermoplastic polyurethane elastomer with a low glass transition temperature and a second thermoplastic polyurethane elastomer with a high glass transition temperature. The first thermoplastic polyurethane elastomer has a glass transition temperature of -60 to -30°C, and the second thermoplastic polyurethane elastomer has a glass transition temperature of -25 to 10°C. During preparation, the first and second thermoplastic polyurethane elastomers are added to an extruder. They are blended in the extruder to ultimately form the thermoplastic polyurethane elastomer alloy layer. The thermoplastic polyurethane elastomer alloy layer can be prepared by casting or coating, and the diaphragm 20 can be prepared by pressure molding.

[0037] The glass transition temperature was measured using DSC, with the standard being GB / T 19466.1-2004, and the heating rate being 20℃ / min.

[0038] In this embodiment of the present invention, the diaphragm 20 includes at least one layer of thermoplastic polyurethane elastomer alloy; since the thermoplastic polyurethane elastomer alloy layer includes thermoplastic polyurethane elastomers with different glass transition temperatures, it can effectively expand the damping temperature range of the diaphragm 20, and the diaphragm 20 can maintain good damping stability in a wider operating temperature range and a wider amplitude range.

[0039] In some specific embodiments of this utility model, the soft segment of the first thermoplastic polyurethane elastomer includes at least one of polycaprolactone, polybutylene adipate, polytetrahydrofuran, polyethylene oxide, polypropylene oxide, and copolyether, and the mass content of the soft segment of the first thermoplastic polyurethane elastomer is 35%-80%.

[0040] In this embodiment, the first thermoplastic polyurethane elastomer is selected from one or more thermoplastic polyurethane elastomers selected from polycaprolactone, polybutylene adipate, polytetrahydrofuran, polyethylene oxide, polypropylene oxide, and copolyether. All of the above materials meet the glass transition temperature requirements of the first thermoplastic polyurethane elastomer.

[0041] Furthermore, by adjusting the ratio of soft segments to hard segments in the first thermoplastic polyurethane elastomer, the performance of the first thermoplastic polyurethane elastomer can be further optimized. When the mass content of soft segments in the first thermoplastic polyurethane elastomer is less than 35%, the corresponding content of hard segments is too high, resulting in excessively high hardness, poor elasticity, and excessively high glass transition temperature of the diaphragm 20, leading to insufficient low-temperature performance. When the mass content of soft segments in the first thermoplastic polyurethane elastomer is greater than 80%, the soft segments change from a dispersed phase to a continuous phase, resulting in poor dimensional stability, high permanent deformation, poor heat resistance, insufficient hardness, poor mechanical properties, and a low glass transition temperature of the diaphragm 20. When the mass content of soft segments in the first thermoplastic polyurethane elastomer is between 35% and 80%, the glass transition temperature and hardness of the diaphragm 20 are moderate, as are its low-temperature performance and heat resistance.

[0042] Optionally, the mass content of the soft segment of the first thermoplastic polyurethane elastomer is 35%, 40%, 50%, 60%, 70%, or 80%, which can be selected by those skilled in the art according to actual needs.

[0043] In some specific embodiments of this utility model, the soft segment of the second thermoplastic polyurethane elastomer includes at least one of polyethylene adipate, butanediol-based polycarbonate, hexanediol-based polycarbonate, 2-methyl-1,3-propanediol-based polycarbonate, copolycarbonate, and copolyester, and the mass content of the soft segment of the second thermoplastic polyurethane elastomer is 20%-70%.

[0044] In this embodiment, the second thermoplastic polyurethane elastomer is selected from one or more thermoplastic polyurethane elastomers selected from polyethylene adipate, butanediol-based polycarbonate, hexanediol-based polycarbonate, 2-methyl-1,3-propanediol-based polycarbonate, copolycarbonate, and copolyester. All of the above materials meet the glass transition temperature requirements of the second thermoplastic polyurethane elastomer.

[0045] Furthermore, when the mass content of the soft segment in the second thermoplastic polyurethane elastomer is less than 20%, the correspondingly high content of the hard segment results in excessively high hardness, poor elasticity, and an excessively high glass transition temperature for the diaphragm 20, leading to insufficient low-temperature performance. When the mass content of the soft segment in the second thermoplastic polyurethane elastomer is greater than 70%, the soft segment changes from a dispersed phase to a continuous phase, resulting in poor dimensional stability, high permanent deformation, poor heat resistance, insufficient hardness, poor mechanical properties, and a low glass transition temperature for the diaphragm 20. When the soft segment content of the second thermoplastic polyurethane elastomer is between 20% and 70%, the diaphragm 20 exhibits moderate glass transition temperature, moderate hardness, and moderate low-temperature and heat resistance.

[0046] Optionally, the mass content of the soft segment of the second thermoplastic polyurethane elastomer is 20%, 30%, 35%, 40%, 50%, 60%, or 70%, which can be selected by those skilled in the art according to actual needs.

[0047] In some specific embodiments of this utility model, the ratio of the mass of the first thermoplastic polyurethane elastomer to the sum of the masses of the first thermoplastic polyurethane elastomer and the second thermoplastic polyurethane elastomer is 30%-95%.

[0048] And / or, the mass ratio of the second thermoplastic polyurethane elastomer to the sum of the masses of the first thermoplastic polyurethane elastomer and the second thermoplastic polyurethane elastomer is 5%-70%.

[0049] In this embodiment, the damping temperature range of the diaphragm 20 is related to the ratio of the high glass transition temperature component and the low glass transition temperature component. By limiting the ratio of the first thermoplastic polyurethane elastomer and the second thermoplastic polyurethane elastomer in the thermoplastic polyurethane elastomer alloy layer, the diaphragm 20 can have a wider damping temperature range.

[0050] Specifically, when the ratio of the mass of the first thermoplastic polyurethane elastomer to the sum of the masses of the first and second thermoplastic polyurethane elastomers is less than 30%, correspondingly, the ratio of the mass of the second thermoplastic polyurethane elastomer to the sum of the masses of the first and second thermoplastic polyurethane elastomers is greater than 70%. In this case, the content of the first thermoplastic polyurethane elastomer is too low, the modulus of the diaphragm 20 changes too rapidly with temperature, and the F0 stability at low temperatures (-20℃ to 0℃) is poor. When the ratio of the mass of the first thermoplastic polyurethane elastomer to the sum of the masses of the first and second thermoplastic polyurethane elastomers is greater than 95%, correspondingly, the ratio of the mass of the second thermoplastic polyurethane elastomer to the sum of the masses of the first and second thermoplastic polyurethane elastomers is less than 5%. In this case, the content of the second thermoplastic polyurethane elastomer is too low, the damping temperature range of the diaphragm 20 is narrow, and the room temperature damping factor of the diaphragm 20 is small, resulting in poor damping performance at room temperature (23℃). When the mass ratio of the first thermoplastic polyurethane elastomer to the sum of the masses of the first and second thermoplastic polyurethane elastomers is 30%-95%, and correspondingly, the mass ratio of the second thermoplastic polyurethane elastomer to the sum of the masses of the first and second thermoplastic polyurethane elastomers is 5%-70%, the diaphragm 20 has a wide damping temperature range and a high room temperature damping factor, while also taking into account the modulus change rate.

[0051] Optionally, the ratio of the mass of the first thermoplastic polyurethane elastomer to the sum of the masses of the first and second thermoplastic polyurethane elastomers is 30%, 40%, 50%, 60%, 70%, 80%, 95%, etc. The ratio of the mass of the second thermoplastic polyurethane elastomer to the sum of the masses of the first and second thermoplastic polyurethane elastomers is 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, etc. Those skilled in the art can set these ratios according to actual needs.

[0052] In some specific embodiments of this utility model, the thermoplastic polyurethane elastomer alloy layer further includes an antioxidant, which includes pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-dimethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-methyl At least one of the following: triazine-2,4,6-trione, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, dilauryl thiodipropionate, distearate thiodipropionate, pentaerythritol tetra(β-thiopropyl laurylate), and 2,6-di-tert-butyl-p-cresol, wherein the antioxidant is added to the thermoplastic polyurethane elastomer alloy layer in an amount of 0.1 phr-2 phr;

[0053] And / or, the thermoplastic polyurethane elastomer alloy layer further includes an anti-hydrolysis agent, the anti-hydrolysis agent including at least one of polycarbodiimide, monomeric carbodiimide, and liquid-modified carbodiimide, the amount of the anti-hydrolysis agent added to the thermoplastic polyurethane elastomer alloy layer being 0.5 phr-5 phr;

[0054] And / or, the thermoplastic polyurethane elastomer alloy layer further includes an ultraviolet absorber, the ultraviolet absorber including at least one of 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol, 2-hydroxy-4-n-octyloxybenzophenone, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, a polymer of succinic acid and (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol), and polymethylpropyl-3-oxo-[4(2,2,6,6-tetramethyl)piperidinyl]siloxane, wherein the amount of the ultraviolet absorber added to the thermoplastic polyurethane elastomer alloy layer is 0.1 phr-2 phr;

[0055] And / or, the thermoplastic polyurethane elastomer alloy layer further includes a processing aid, the processing aid including at least one of polytalc, dimethylsiloxane, polyethylene wax, fatty acid ester, and fatty acid salt, and the amount of the processing aid added to the thermoplastic polyurethane elastomer alloy layer is 0.1 phr-5 phr.

[0056] In this embodiment of the invention, the antioxidant can inhibit the oxidative degradation of TPU during processing or long-term use, thereby improving the reliability of the diaphragm 20. The thermoplastic polyurethane elastomer alloy layer can be selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-dimethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) The antioxidant is selected from any one or a mixture of several of the following: triazine-2,4,6-trione, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, dilauryl thiodipropionate, distearate thiodipropionate, pentaerythritol tetra(β-thiopropyl laurylate), and 2,6-di-tert-butyl-p-cresol. The antioxidant addition amount in the thermoplastic polyurethane elastomer alloy layer is 0.1 phr-2 phr, meaning 0.1-2 parts by weight are added to 100 parts by weight of the first and second thermoplastic polyurethane elastomers. When the antioxidant addition amount in the thermoplastic polyurethane elastomer alloy layer is less than 0.1 phr, the antioxidant's effect on inhibiting TPU oxidative degradation is not significant. When the amount of antioxidant added to the thermoplastic polyurethane elastomer alloy layer is greater than 2 phr, the antioxidant is prone to precipitation. When the amount of antioxidant added to the thermoplastic polyurethane elastomer alloy layer is 0.1 phr-2 phr, the antioxidant has a significant effect on inhibiting the oxidative degradation of TPU and is less prone to precipitation.

[0057] Optionally, the amount of antioxidant added to the thermoplastic polyurethane elastomer alloy layer is 0.1 phr, 0.5 phr, 1 phr, 1.5 phr, 2 phr, etc., which can be set by those skilled in the art according to actual needs.

[0058] The anti-hydrolysis agent can improve the water resistance of TPU, prevent TPU from hydrolyzing in humid environments, and improve the reliability of the diaphragm 20. The thermoplastic polyurethane elastomer alloy layer can be selected from any one or a mixture of multiple types of polycarbodiimide, monomeric carbodiimide, and liquid-modified carbodiimide. The amount of anti-hydrolysis agent added to the thermoplastic polyurethane elastomer alloy layer is 0.5 phr-5 phr, which means adding 0.5 to 5 parts by weight to a total mass of 100 parts by weight of the first and second thermoplastic polyurethane elastomers. When the amount of anti-hydrolysis agent added to the thermoplastic polyurethane elastomer alloy layer is less than 0.5 phr, the effect of the anti-hydrolysis agent in improving the water resistance of TPU is not significant. When the amount of anti-hydrolysis agent added to the thermoplastic polyurethane elastomer alloy layer is greater than 5 phr, the anti-hydrolysis agent is prone to precipitation. When the amount of anti-hydrolysis agent added to the thermoplastic polyurethane elastomer alloy layer is 0.5 phr-5 phr, the anti-hydrolysis agent significantly improves the water resistance of TPU and is less prone to precipitation.

[0059] Optionally, the amount of anti-hydrolysis agent added to the thermoplastic polyurethane elastomer alloy layer is 0.1 phr, 1 phr, 2 phr, 3 phr, 4 phr, 5 phr, etc., which can be set by those skilled in the art according to actual needs.

[0060] Ultraviolet absorbers can slow down the aging of TPU under sunlight and / or UV irradiation, improving the reliability of the diaphragm 20. The thermoplastic polyurethane elastomer alloy layer can be selected from any one or a mixture of multiples of 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol, 2-hydroxy-4-n-octyloxybenzophenone, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, a polymer of succinic acid and (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol), and polymethylpropyl-3-oxo-[4(2,2,6,6-tetramethyl)piperidinyl]siloxane. The addition amount of UV absorber in the thermoplastic polyurethane elastomer alloy layer is 0.1 phr-2 phr, which means adding 0.1 to 2 parts by weight to 100 parts by weight of the first and second thermoplastic polyurethane elastomers. When the addition amount of UV absorber in the thermoplastic polyurethane elastomer alloy layer is less than 0.1 phr, the effect of UV absorber in slowing down the aging of TPU under sunlight and / or UV irradiation is not significant. When the addition amount of UV absorber in the thermoplastic polyurethane elastomer alloy layer is greater than 2 phr, the UV absorber is prone to precipitation. When the addition amount of UV absorber in the thermoplastic polyurethane elastomer alloy layer is 0.1 to 2 phr, the effect of UV absorber in slowing down the aging of TPU under sunlight and / or UV irradiation is significant and precipitation is not easily observed.

[0061] Optionally, the amount of ultraviolet absorber added to the thermoplastic polyurethane elastomer alloy layer is 0.1 phr, 1 phr, 1.5 phr, 2 phr, etc., which can be set by those skilled in the art according to actual needs.

[0062] Processing aids can optimize the processing performance of TPU and adjust the viscosity of the TPU surface. The thermoplastic polyurethane elastomer alloy layer can be composed of any one or a mixture of multiple ingredients selected from polytalc, dimethylsiloxane, polyethylene wax, fatty acid esters, and fatty acid salts. The addition amount of processing aid in the thermoplastic polyurethane elastomer alloy layer is 0.1 phr-5 phr, meaning 0.1-5 parts by weight are added to 100 parts by weight of the total mass of the first and second thermoplastic polyurethane elastomers. When the addition amount of processing aid in the thermoplastic polyurethane elastomer alloy layer is less than 0.1 phr, the effect of processing aid in reducing the viscosity of the TPU surface and optimizing the processing performance of TPU is not significant. When the addition amount of processing aid in the thermoplastic polyurethane elastomer alloy layer is greater than 5 phr, the processing aid is prone to precipitation. When the addition amount of processing aid in the thermoplastic polyurethane elastomer alloy layer is 0.1-5 phr, the effect of processing aid in reducing the viscosity of the TPU surface and optimizing the processing performance of TPU is significant and precipitation is less likely.

[0063] Optionally, the amount of processing aid added to the thermoplastic polyurethane elastomer alloy layer is 0.1 phr, 1 phr, 2 phr, 3 phr, 4 phr, 5 phr, etc., which can be set by those skilled in the art according to actual needs.

[0064] In some specific embodiments of this utility model, the thickness of the thermoplastic polyurethane elastomer alloy layer is 10μm-150μm;

[0065] And / or, the density of the thermoplastic polyurethane elastomer alloy layer is 1.10 g / cm³. 3 -1.30g / cm 3 .

[0066] In this embodiment, the thermoplastic polyurethane elastomer alloy layer is used to prepare the diaphragm 20 using a basic casting process. The thickness of the diaphragm 20 has a significant impact on its performance. When the thickness of the diaphragm 20 is too low, for example, less than 10 μm, the film formation and uniformity of the extrusion casting are poor, and the diaphragm 20 experiences an increase in the number of split vibration modes during vibration, resulting in higher distortion. When the thickness of the diaphragm 20 is too high, for example, greater than 150 μm, it affects the vibration space of the diaphragm 20, making it more prone to collisions with the housing, and reducing the mid-frequency sensitivity. When the thickness of the diaphragm 20 is between 10 μm and 150 μm, it ensures both ease of processing and conserves vibration space while maintaining acoustic performance.

[0067] Optionally, the thickness of the diaphragm 20 can be 10μm, 40μm, 50μm, 80μm, 100μm, 120μm, 150μm, etc., and those skilled in the art can set it according to actual needs.

[0068] The density of the thermoplastic polyurethane elastomer alloy layer has a significant impact on the mid-frequency performance of the diaphragm 20. When the density of the thermoplastic polyurethane elastomer alloy layer is too high, for example, greater than 1.30 g / cm³, it becomes problematic. 3 At this time, the mass of the diaphragm 20 of the same size is too large, requiring a large driving force, and the mid-frequency performance of the sound-generating device using the diaphragm 20 deteriorates. When the density of the diaphragm 20 is too small, for example less than 1.10 g / cm³, the density of the diaphragm 20 is also too small. 3 At this time, the addition of plasticizers poses a risk of precipitation. When the density of diaphragm 20 is 1.10 g / cm³... 3 -1.30g / cm 3 At that time, the diaphragm 20 has a moderate mass and good mid-frequency performance.

[0069] Optionally, the density of the diaphragm 20 is 1.10 g / cm³. 3 1.15g / cm 3 1.20g / cm 3 1.25g / cm 3 1.30g / cm 3 The settings can be configured according to actual needs by those skilled in the art.

[0070] In some specific embodiments of this utility model, the Young's modulus of the thermoplastic polyurethane elastomer alloy layer is 5MPa-200MPa;

[0071] And / or, the 5-minute creep recovery rate of the thermoplastic polyurethane elastomer alloy layer is 60%-98%.

[0072] The Young's modulus of the thermoplastic polyurethane elastomer alloy layer has a significant impact on the vibration performance of the diaphragm 20. When the Young's modulus of the thermoplastic polyurethane elastomer alloy layer is less than 5 MPa, the diaphragm 20 is prone to resonance and segmented vibration, resulting in large distortion. Furthermore, when the Young's modulus is low, the thickness of the diaphragm 20 needs to be increased to ensure that its mechanical properties meet requirements, thus limiting the vibration space of the diaphragm 20 and making it prone to collapse. When the Young's modulus of the thermoplastic polyurethane elastomer alloy layer is greater than 200 MPa, the diaphragm 20 is prone to low low-frequency loudness and insufficient vibration depth, forming a mid-frequency trough. When the Young's modulus of the thermoplastic polyurethane elastomer alloy layer is between 5 MPa and 200 MPa, the diaphragm 20 is less prone to resonance and segmented vibration, has low distortion, high low-frequency loudness, and good mid-frequency performance.

[0073] Optionally, the Young's modulus of the diaphragm 20 is 5MPa, 50MPa, 100MPa, 150MPa, 200MPa, etc., which can be set by those skilled in the art according to actual needs.

[0074] The 5-minute creep recovery rate of the thermoplastic polyurethane elastomer alloy layer in this embodiment of the invention is 60%-98%.

[0075] Creep recovery rate is the percentage decrease in material strain within a set time after the tensile load is unloaded, relative to the strain at the time of unloading. Creep recovery rate characterizes the material's ability to recover deformation after creep. If the creep recovery rate is too small, the thermoplastic polyurethane elastomer alloy layer has poor deformation recovery ability after creep; if the creep recovery rate is too large, the damping performance of the thermoplastic polyurethane elastomer alloy layer decreases. In this embodiment, the 5-minute creep recovery rate of the thermoplastic polyurethane elastomer alloy layer is 60%-98%, enabling the diaphragm 20 to possess both good damping performance and strong deformation recovery ability after creep.

[0076] The creep recovery rate test method can be based on GB / T 11546.1-2008 standard, with a stress of 0.1 MPa, a holding time of 5 min, a creep time of 10 min, and a recovery time of 5 min.

[0077] In some specific embodiments of this utility model, the hardness of the thermoplastic polyurethane elastomer alloy layer is 70A-95A.

[0078] The hardness of the thermoplastic polyurethane elastomer alloy layer has a significant impact on the vibration performance of the diaphragm 20. When the hardness of the thermoplastic polyurethane elastomer alloy layer is less than 70A, the diaphragm 20 is prone to resonance and segmented vibration, resulting in high distortion. Furthermore, when the hardness is low, the thickness of the diaphragm 20 needs to be increased to ensure that its mechanical properties meet requirements, thus limiting the vibration space of the diaphragm 20 and making it prone to collapse. When the hardness of the thermoplastic polyurethane elastomer alloy layer is greater than 95A, the diaphragm 20 is prone to low low-frequency loudness and insufficient vibration depth, forming a mid-frequency trough. When the hardness of the thermoplastic polyurethane elastomer alloy layer is between 70A and 95A, the diaphragm 20 is less prone to resonance and segmented vibration, has low distortion, high low-frequency loudness, and good mid-frequency performance.

[0079] Optionally, the stiffness of the diaphragm 20 can be 70A, 75A, 80A, 85A, 90A, 95A, etc., which can be set by those skilled in the art according to actual needs.

[0080] In some specific embodiments of this utility model, the Young's modulus change rate of the thermoplastic polyurethane elastomer alloy layer after heat treatment at 130℃ for 90s-300s is ≤50%.

[0081] And / or, the Young's modulus change rate of the thermoplastic polyurethane elastomer alloy layer after heat treatment at 130°C for 90s-300s followed by constant humid heat treatment at 85°C, 85%RH, and 96h is ≤50%.

[0082] In this embodiment, the thermoplastic polyurethane elastomer alloy layer is heat-treated at 130°C for 90-300 seconds. The change rate of Young's modulus before and after the heat treatment is calculated based on the change in Young's modulus. A higher change rate of Young's modulus indicates poorer heat resistance of the diaphragm 20. In this embodiment, the change rate of Young's modulus of the thermoplastic polyurethane elastomer alloy layer is ≤50%, indicating good heat resistance of the diaphragm 20.

[0083] Alternatively, the thermoplastic polyurethane elastomer alloy layer is subjected to heat treatment at 130℃ for 90-300 seconds, followed by constant humidity heat treatment at 85℃ and 85% RH for 96 hours. The change rate of Young's modulus before and after the placement of the thermoplastic polyurethane elastomer alloy layer is calculated based on the change in Young's modulus. A higher Young's modulus change rate indicates unstable long-term performance of the diaphragm 20 under high temperature and humidity, and a large deviation of F0 from the design value. In this embodiment, the change rate of Young's modulus of the thermoplastic polyurethane elastomer alloy layer is ≤50%, the long-term performance of the diaphragm 20 under high temperature and humidity is stable, and the change in F0 is small.

[0084] It should be noted that after the above-mentioned high temperature treatment and / or high temperature and high humidity treatment, the Young's modulus of the diaphragm 20 may decrease or increase.

[0085] In some specific embodiments of this utility model, the diaphragm 20 is formed as a single-layer structure, and the diaphragm 20 is composed of a single layer of thermoplastic polyurethane elastomer alloy;

[0086] Alternatively, the diaphragm 20 may be formed as a multilayer structure, comprising at least one thermoplastic polyurethane elastomer alloy layer and a composite layer, wherein the composite layer is stacked with the thermoplastic polyurethane elastomer alloy layer, and the composite layer is at least one of an elastomer layer, an engineering plastic layer, and a film layer.

[0087] In other words, the diaphragm 20 in this embodiment of the invention can be a single-layer thermoplastic polyurethane elastomer alloy layer. The diaphragm 20 has a simple structure and a simple manufacturing process.

[0088] Alternatively, the diaphragm 20 can be a multi-layer structure. That is, at least one thermoplastic polyurethane elastomer alloy layer is stacked with a composite layer to form a multi-layer diaphragm 20. The composite layer is at least one of an elastomer layer, an engineering plastic layer, and a film layer. The number of layers in the multi-layer structure can be 2, 3, 4, 5, 6, 7, etc.

[0089] Optionally, the elastomer layer includes one or more of thermoplastic polyester elastomers, thermoplastic polyamide elastomers, polystyrene elastomers, and polyolefin thermoplastic elastomers. The engineering plastic layer includes one or more of PEEK, PAR, PMI, PET, PEN, PA, PEI, and LCP. The film layer is a silicone film and / or an acrylic film. The composite layer is one or more layers.

[0090] According to another embodiment of the present invention, a sound-generating device is provided. For example... Figures 2-3 As shown, the sound-generating device 100 includes the diaphragm 20 of the above embodiment.

[0091] like Figures 2-3 As shown, the sound-generating device 100 may include a housing 10, a magnetic circuit system, and a vibration system. The magnetic circuit system includes a permanent magnet 40, which forms a magnetic gap. The vibration system includes a diaphragm 20 and a voice coil 30. Both the diaphragm 20 and the permanent magnet 40 are connected to the housing 10. The permanent magnet 40 is disposed on one side of the diaphragm 20 along its thickness direction. One end of the voice coil 30 is connected to the diaphragm 20, and the other end is located within the magnetic gap.

[0092] In this example, the diaphragm 20 can be a surround diaphragm. The surround diaphragm includes a central portion, a surround portion, and a fixing portion connected sequentially from the inside out. The fixing portion is used to connect to the housing 10. A dome is provided on the central portion, and the voice coil 30 is connected to the central portion or the dome.

[0093] In other examples, the diaphragm 20 may also be a planar diaphragm or other structures, which can be determined by those skilled in the art according to the actual situation, and no specific limitation is made here.

[0094] According to another embodiment of the present invention, an electronic device is provided.

[0095] Electronic devices include, for example, mobile phones, computers, televisions, speakers, walkie-talkies, VR devices, AR devices, and smart glasses. This electronic device includes the sound-generating device 100 described in the above embodiments. Of course, the electronic device of this invention also includes at least all the beneficial effects of the above embodiments, which will not be elaborated upon here.

[0096] The diaphragm 20 and the sound-generating device 100 of this utility model will be described in detail below with reference to specific embodiments. It should be noted that the following description is merely exemplary and not a specific limitation of this utility model.

[0097] Example:

[0098] The diaphragm 20 has a single-layer structure, comprising a thermoplastic polyurethane elastomer alloy layer. The diaphragm 20 is formed using air compression molding. The thermoplastic polyurethane elastomer alloy layer includes a first thermoplastic polyurethane elastomer and a second thermoplastic polyurethane elastomer. The mass ratio of the second thermoplastic polyurethane elastomer to the sum of the masses of the first and second thermoplastic polyurethane elastomers is 20%. The thickness of the diaphragm 20 is 90 μm. The diaphragm 20 is a folded ring diaphragm.

[0099] The first thermoplastic polyurethane elastomer has a glass transition temperature of -37°C. The soft segment of the first thermoplastic polyurethane elastomer is polybutylene adipate with a molecular weight of 2100, and the hard segment is 4,4'-diphenylmethane diisocyanate and 1,4-butanediol. The molar ratio of polybutylene adipate:4,4'-diphenylmethane diisocyanate:1,4-butanediol is 1:2:1. The second thermoplastic polyurethane elastomer has a glass transition temperature of -22°C. The soft segment of the second thermoplastic polyurethane elastomer is polyethylene adipate with a molecular weight of 2000, and the hard segment is 4,4'-diphenylmethane diisocyanate and 1,4-butanediol. The molar ratio of polyethylene adipate:4,4'-diphenylmethane diisocyanate:1,4-butanediol is 2:5:3.

[0100] Comparative Example 1:

[0101] The diaphragm 20 is a single-layer structure, prepared by pressure molding of a single-component thermoplastic polyurethane elastomer. The soft segment of the thermoplastic polyurethane elastomer is polybutylene adipate with a molecular weight of 2000. The hard segment is 4,4'-diphenylmethane diisocyanate and 1,4-butanediol. The molar ratio of polybutylene adipate:4,4'-diphenylmethane diisocyanate:1,4-butanediol is 1:2:1. The glass transition temperature of the diaphragm 20 in Comparative Example 1 is -35℃. The thickness of the diaphragm 20 is 73 μm.

[0102] Comparative Example 2:

[0103] The diaphragm 20 is a single-layer structure, fabricated by pressure molding of a single-component thermoplastic polyurethane elastomer. The soft segment of the thermoplastic polyurethane elastomer is polybutylene adipate with a molecular weight of 2100, and the hard segment is 4,4'-diphenylmethane diisocyanate and 1,4-butanediol. The molar ratio of polybutylene adipate:4,4'-diphenylmethane diisocyanate:1,4-butanediol is 1:2:1. The glass transition temperature of the diaphragm 20 in Comparative Example 2 is -37℃. The thickness of the diaphragm 20 is 100 μm.

[0104] Comparative Example 3:

[0105] The diaphragm 20 is a single-layer structure, prepared by pressure molding of a single-component thermoplastic polyurethane elastomer. The soft segment of the thermoplastic polyurethane elastomer is polybutylene adipate with a molecular weight of 2000. The hard segment is 4,4'-diphenylmethane diisocyanate and 1,4-butanediol. The molar ratio of polybutylene adipate:4,4'-diphenylmethane diisocyanate:1,4-butanediol is 2:5:3. The glass transition temperature of the diaphragm 20 in Comparative Example 3 is -22℃. The thickness of the diaphragm 20 is 65 μm.

[0106] In Comparative Example 2, the composition is the same as that of the first thermoplastic polyurethane elastomer in the Examples. In Comparative Example 3, the composition is the same as that of the second thermoplastic polyurethane elastomer in the Examples. The F0 values ​​of the diaphragm 20 in the Examples and the diaphragms in Comparative Examples 1, 2, and 3 are consistent.

[0107] Test items:

[0108] (1) The temperature ranges in which the loss factor of the diaphragm 20 of Examples 1, 2 and 3 is greater than 0.1 and greater than 0.12 were tested respectively.

[0109] The loss factor, also known as the damping factor, is the ratio of the loss modulus to the storage modulus. It is tested using a dynamic thermomechanical analyzer according to the ASTM D5026-23 standard. The frequency is 1 Hz, and the strain is 0.2%.

[0110] (2) Test the energy storage modulus of the diaphragm 20 of Examples 1, 2 and 3 at -20℃ and 20℃ respectively, and calculate the rate of change of energy storage modulus.

[0111] The energy storage modulus was tested using a dynamic thermomechanical analyzer under the following conditions: ASTM D5026-23 standard, tensile mode, heating rate of 3℃ / min, and frequency of 1Hz.

[0112] The calculation method for the rate of change of energy storage modulus at -20℃ / 20℃ is as follows:

[0113]

[0114] (3) Six-point amplitude test: The diaphragm 20 of the embodiment and comparative example 1 were assembled into the sound-generating device, and the displacement curves of five points on the edge of the diaphragm 20 and one point at the center position as a function of frequency were measured. The diaphragm 20 of the embodiment and comparative example 1 are both rectangular folded ring diaphragms, and their dimensions are similar.

[0115] Results and Analysis:

[0116] (1) The test results of the diaphragm 20 in Examples 1, 2, and 3 are shown in Table 1. The damping factor of the diaphragm 20 in Examples 1, 2, and 3 as a function of temperature is shown in the curves below. Figure 4 , Figure 5 As shown.

[0117] Table 1 - Test results of diaphragm 20 in Examples 1, 2, and 3 (Comparative Examples 1, 2, and 3)

[0118]

[0119]

[0120] From Table 1 and Figure 4 , Figure 5 It is evident that although the rate of change of storage modulus at -20℃ / 20℃ of the diaphragm 20 in this embodiment is similar to that of the diaphragm in Comparative Example 1, the diaphragm 20 in this embodiment has a wider temperature range for damping factor >0.10 and a wider temperature range for damping factor >0.12 compared to the diaphragm in Comparative Example 1. While the diaphragm in Comparative Example 2 has a smaller rate of change of storage modulus at -20℃ / 20℃, its temperature ranges for damping factor >0.10 and >0.12 are narrower. Although the diaphragm in Comparative Example 3 has a wider temperature range for damping factor >0.10 and >0.12, its rate of change of storage modulus at -20℃ / 20℃ is high, which fails to meet the requirements of the sound-generating device. Although the rate of change of energy storage modulus of the diaphragm 20 in this embodiment of the present invention is higher than that of the diaphragm 20 in Comparative Example 2, its value is relatively small and at the general level in the industry, still meeting the usage requirements of the sound-generating device. The temperature ranges with damping factors >0.10 and >0.12 of the diaphragm 20 in this embodiment of the present invention extend into the low-temperature region compared to the temperature ranges with damping factors >0.10 and >0.12 of the diaphragm in Comparative Example 3. Therefore, the diaphragm 20 in this embodiment of the present invention can possess a lower rate of change of energy storage modulus at -20℃ / 20℃, and the temperature ranges with damping factors >0.10 and >0.12 of the diaphragm 20 are wider. The overall performance of the diaphragm in this embodiment of the present invention is better. This is mainly because the thermoplastic polyurethane elastomer alloy layer includes thermoplastic polyurethane elastomers with different glass transition temperatures, thus effectively expanding the damping temperature range of the diaphragm 20. The diaphragm 20 can maintain good damping stability over a wider operating temperature range and a wider frequency range.

[0121] (2) Figure 4 The curves showing the six-point amplitude variation of the diaphragm 20 in this embodiment of the present invention with frequency are shown. Figure 5 The curves showing the six-point amplitude of diaphragm 20 as a function of frequency are shown in Comparative Example 1.

[0122] Depend on Figure 4 and Figure 5As can be seen, the six-point amplitude curve of this embodiment is more concentrated than that of Comparative Example 1. This indicates that the diaphragm 20 of this embodiment has good amplitude consistency. This is mainly because the thermoplastic polyurethane elastomer alloy layer includes a first thermoplastic polyurethane elastomer and a second thermoplastic polyurethane elastomer with different glass transition temperatures. Therefore, the loss factor of the diaphragm 20 is high over a wider operating temperature range, resulting in good overall performance of the diaphragm 20 and good amplitude consistency in various parts.

[0123] In summary, the diaphragm 20 of this embodiment includes a thermoplastic polyurethane elastomer alloy layer. Since this layer comprises thermoplastic polyurethane elastomers with different glass transition temperatures, it effectively extends the damping temperature range of the diaphragm 20. The diaphragm 20 maintains good damping stability over a wider operating temperature range and amplitude range. Furthermore, the diaphragm 20 of this embodiment exhibits a low storage modulus change rate at -20℃ / 20℃, and a wide temperature range with a damping factor >0.10 and a damping factor >0.12. Additionally, the diaphragm 20 of this embodiment demonstrates good amplitude consistency.

[0124] The above embodiments mainly describe 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. For the sake of brevity, they will not be elaborated here.

[0125] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A diaphragm for a sound-generating device, characterized in that, The diaphragm includes at least one thermoplastic polyurethane elastomer alloy layer, which includes a first thermoplastic polyurethane elastomer and a second thermoplastic polyurethane elastomer. The thickness of the thermoplastic polyurethane elastomer alloy layer is 10 μm-150 μm. The thermoplastic polyurethane elastomer alloy layer has a first glass transition temperature and a second glass transition temperature. The first glass transition temperature is -60°C to -30°C, and the second glass transition temperature is -25°C to 10°C.

2. The diaphragm according to claim 1, characterized in that, The soft segment of the first thermoplastic polyurethane elastomer includes one of polycaprolactone, polybutylene adipate, polytetrahydrofuran, polyethylene oxide, polypropylene oxide, and copolyether.

3. The diaphragm according to claim 1, characterized in that, The soft segment of the second thermoplastic polyurethane elastomer includes one of polyethylene adipate, butanediol-based polycarbonate, hexanediol-based polycarbonate, 2-methyl-1,3-propanediol-based polycarbonate, copolycarbonate, and copolyester.

4. The diaphragm according to claim 1, characterized in that, The Young's modulus of the thermoplastic polyurethane elastomer alloy layer is 5 MPa-200 MPa; And / or, the 5-minute creep recovery rate of the thermoplastic polyurethane elastomer alloy layer is 60%-98%.

5. The diaphragm according to claim 1, characterized in that, The density of the thermoplastic polyurethane elastomer alloy layer is 1.10 g / cm³. 3 -1.30g / cm 3 .

6. The diaphragm according to claim 1, characterized in that, The hardness of the thermoplastic polyurethane elastomer alloy layer is 70A-95A.

7. The diaphragm according to claim 1, characterized in that, The Young's modulus of the thermoplastic polyurethane elastomer alloy layer decreases by ≤50% after heat treatment at 130℃ for 90s-300s. And / or, the Young's modulus change rate of the thermoplastic polyurethane elastomer alloy layer after heat treatment at 130°C for 90s-300s followed by constant humid heat treatment at 85°C, 85%RH, and 96h is ≤50%.

8. The diaphragm according to any one of claims 1-7, characterized in that, The diaphragm is formed as a single-layer structure, and the diaphragm is composed of a single layer of the thermoplastic polyurethane elastomer alloy; Alternatively, the diaphragm may be formed as a multilayer structure, comprising at least one thermoplastic polyurethane elastomer alloy layer and a composite layer, wherein the composite layer is stacked with the thermoplastic polyurethane elastomer alloy layer, and the composite layer is at least one of an elastomer layer, an engineering plastic layer, and a film layer.

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

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

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