WO2021208473A1 - 一种振膜以及发声装置 - Google Patents

一种振膜以及发声装置 Download PDF

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Publication number
WO2021208473A1
WO2021208473A1 PCT/CN2020/136207 CN2020136207W WO2021208473A1 WO 2021208473 A1 WO2021208473 A1 WO 2021208473A1 CN 2020136207 W CN2020136207 W CN 2020136207W WO 2021208473 A1 WO2021208473 A1 WO 2021208473A1
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Prior art keywords
rubber
diaphragm
foamed
foamed rubber
layer
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Ceased
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PCT/CN2020/136207
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English (en)
French (fr)
Inventor
惠冰
凌风光
李春
刘春发
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Goertek Inc
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Goertek Inc
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Publication of WO2021208473A1 publication Critical patent/WO2021208473A1/zh
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B25/00—Layered products comprising a layer of natural or synthetic rubber
    • B32B25/04—Layered products comprising a layer of natural or synthetic rubber comprising rubber as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B25/00—Layered products comprising a layer of natural or synthetic rubber
    • B32B25/12—Layered products comprising a layer of natural or synthetic rubber comprising natural rubber
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B25/00—Layered products comprising a layer of natural or synthetic rubber
    • B32B25/14—Layered products comprising a layer of natural or synthetic rubber comprising synthetic rubber copolymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B25/00—Layered products comprising a layer of natural or synthetic rubber
    • B32B25/16—Layered products comprising a layer of natural or synthetic rubber comprising polydienes homopolymers or poly-halodienes homopolymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B25/00—Layered products comprising a layer of natural or synthetic rubber
    • B32B25/18—Layered products comprising a layer of natural or synthetic rubber comprising butyl or halobutyl rubber
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/18—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer of foamed material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
    • H04R31/003—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor for diaphragms or their outer suspension
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • H04R7/06—Plane diaphragms comprising a plurality of sections or layers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • H04R7/06—Plane diaphragms comprising a plurality of sections or layers
    • H04R7/10—Plane diaphragms comprising a plurality of sections or layers comprising superposed layers in contact
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/12—Non-planar diaphragms or cones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/12—Non-planar diaphragms or cones
    • H04R7/122—Non-planar diaphragms or cones comprising a plurality of sections or layers
    • H04R7/125—Non-planar diaphragms or cones comprising a plurality of sections or layers comprising a plurality of superposed layers in contact
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/06—Loudspeakers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2266/00—Composition of foam
    • B32B2266/02—Organic
    • B32B2266/0207—Materials belonging to B32B25/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/51—Elastic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/718—Weight, e.g. weight per square meter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/72—Density
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2231/00—Details of apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor covered by H04R31/00, not provided for in its subgroups
    • H04R2231/001—Moulding aspects of diaphragm or surround
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2307/00—Details of diaphragms or cones for electromechanical transducers, their suspension or their manufacture covered by H04R7/00 or H04R31/003, not provided for in any of its subgroups
    • H04R2307/025—Diaphragms comprising polymeric materials

Definitions

  • the present invention relates to the technical field of electro-acoustic conversion, and more specifically, the present invention relates to a diaphragm and a sound generating device.
  • the sounding device As an energy converter that converts electrical signals into sound signals, the sounding device is an indispensable device in electroacoustic products. Sound generating devices have been used in various types of terminal electronic products such as mobile phones, tablet computers, notebook computers, navigators, e-books, and smart wearable devices, and their applications are very wide.
  • the diaphragm is arranged in the vibration system of the sound emitting device, and it is one of the more important components in the sound emitting device.
  • the diaphragm of the sound device is mostly made of a rubber film layer (for example, nitrile rubber NBR, butyl rubber IIR, etc.).
  • the above-mentioned diaphragms have relatively poor overall performance, such as high density, low elastic recovery rate, poor heat resistance, etc., resulting in low loudness of the sound device diaphragm and small high and low temperature cycle reliability margin.
  • the diaphragm of this kind of sounding device cannot meet the requirements of high power, waterproof and high sound quality of the sounding device.
  • An object of the present invention is to provide a new technical solution for the diaphragm.
  • a diaphragm comprising a foam rubber membrane layer made of foam rubber
  • the foamed rubber is a foam prepared by a foaming method
  • the cell size of the foamed rubber is 10 ⁇ m to 300 ⁇ m;
  • the glass transition temperature of the foamed rubber is ⁇ -10°C;
  • the density of the foamed rubber is 0.1 g/cm 3 to 1.2 g/cm 3 .
  • the foam rubber is EPDM rubber, hydrogenated nitrile rubber, ethylene-acrylate rubber, acrylate rubber, styrene butadiene rubber, natural rubber, nitrile rubber, butyl rubber, polyurethane rubber, At least one of pentylene rubber, butadiene rubber, vinyl acetate rubber, polysulfide rubber, and fluorine rubber.
  • the foaming method uses a foaming agent
  • the foaming agent is foamed microbeads, azo compounds, nitroso compounds, inorganic compounds, hydrazine compounds, carbon dioxide, nitrogen and butane. At least one of.
  • the added amount of the blowing agent is 0.1 wt% to 20 wt%.
  • the elongation at break of the foamed rubber is ⁇ 100%.
  • the tensile strength of the foamed rubber is 0.1 MPa-50 MPa.
  • the porosity of the foamed rubber is 10% to 90%.
  • the elastic recovery rate of the foamed rubber film layer after 10% strain is ⁇ 80%.
  • the diaphragm is a single-layer diaphragm, and the single-layer diaphragm is made of a layer of foamed rubber membrane; or,
  • the diaphragm is a composite diaphragm, and the composite diaphragm includes two, three, four or five diaphragms, and the composite diaphragm includes at least one foamed rubber diaphragm.
  • it also includes an adhesive film layer;
  • the adhesive force between the adhesive film layer and the foamed rubber film layer is greater than 50 g/25 mm.
  • the thickness of the foamed rubber film layer is 50 ⁇ m to 2000 ⁇ m.
  • a sound generating device includes a vibration system and a magnetic circuit system matched with the vibration system;
  • the vibration system includes the above-mentioned diaphragm.
  • the foamed rubber membrane layer has cells uniformly distributed inside the material, the overall density of the material can be reduced. Compared with the conventional rubber diaphragm of the same size, the membrane can be The weight is significantly reduced. Moreover, the diaphragm made of foam rubber has good resilience, so that the sound generating device can exhibit high sound quality.
  • Fig. 1 is a test curve (SPL curve) of loudness at different frequencies of a diaphragm and a conventional rubber diaphragm according to an embodiment of the present disclosure.
  • Fig. 2 is a harmonic distortion (THD) curve of a diaphragm and a conventional rubber diaphragm according to an embodiment of the present disclosure.
  • TDD harmonic distortion
  • Fig. 3 is a cross-sectional view of a diaphragm provided according to an embodiment of the present disclosure.
  • a diaphragm which can be used in sound generating devices such as large speakers, small speakers, etc., so that the sound generating devices can exhibit higher sound quality.
  • the diaphragm can be, but not limited to, a cone or a flat plate shape.
  • the diaphragm may be a single-layer structure, or a composite structure formed by a combination of multiple membrane layers, which can be flexibly adjusted by those skilled in the art as required, and the present invention does not limit this.
  • the diaphragm provided by the embodiment of the present invention includes a foamed rubber membrane layer made of foamed rubber.
  • the foamed rubber is EPDM, hydrogenated nitrile rubber, ethylene-acrylate rubber, acrylate rubber, styrene butadiene rubber, natural rubber, nitrile rubber, butyl rubber, polyurethane rubber, isoprene rubber , At least one of butadiene rubber, vinyl acetate rubber, polysulfide rubber and fluorine rubber is a foam prepared by a foaming method.
  • the glass transition temperature of the foamed rubber is ⁇ -10°C.
  • the glass transition temperature of the foamed rubber is ⁇ -10°C. The glass transition temperature enables the diaphragm to maintain a high elastic state at room temperature and has good resilience.
  • the glass transition temperature of the foamed rubber is -80°C to -30°C. This enables the diaphragm to maintain good elasticity when working in an environment lower than -20°C, so that the sound generating device using the diaphragm can exhibit higher sound quality. At the same time, the risk of damage to the diaphragm of the sound device in a low temperature environment is reduced, and the reliability of the diaphragm can be higher.
  • the diaphragm of the embodiment of the present invention can meet the requirements of a sound generating device (for example, a horn) for use in a high and low temperature environment.
  • the low temperature performance is more outstanding than the conventional diaphragm (for example, PEEK diaphragm).
  • the diaphragm provided by the embodiment of the present invention still has good structural strength and toughness.
  • the diaphragm vibration has a low risk of membrane rupture and high reliability, which is very suitable for popularization and use.
  • the material used when preparing the diaphragm is foam rubber.
  • the membrane layer made of foam rubber has cells (bubbles) uniformly distributed inside the material, so the overall density of the material can be reduced, and the weight of the diaphragm of the same size can be reduced. This allows the material to have better resilience, greater amplitude, and less likely to deform the diaphragm due to its own weight.
  • the foamed rubber is prepared by the foaming method.
  • the foaming method includes a chemical foaming method or a physical foaming method.
  • the chemical foaming method refers to a method of using a chemical method to generate gas to foam an elastomer material (for example, plastic).
  • the chemical foaming agent added to the elastomer material decomposes after heating, thereby releasing gas, which forms bubbles during the elastomer molding process. It is also possible to use the gas released by the chemical reaction between the different components of the elastomer material to foam during the molding process of the elastomer material.
  • the physical foaming method refers to a method in which bubbles are formed in the material during the material molding process through the physical change of the foaming agent added to the material.
  • the physical foaming method does not affect the chemical properties and molecular structure of the elastomer material, and can form uniform bubbles in the material.
  • the foaming agent used in the preparation of the foamed rubber is foamed microbeads, azo compounds, nitroso compounds, inorganic compounds, hydrazine compounds, carbon dioxide, nitrogen and At least one of butane. All of the above-mentioned foaming agents can form uniform cells (bubbles) inside the material. Moreover, the foaming agents listed above have relatively low cost, are green and environmentally friendly, and are very suitable for mass production in industry. In specific applications, those skilled in the art can flexibly choose according to actual needs.
  • the foamed microbeads are hollow micron-sized spheres, and their material is resin or the like.
  • the foamed microbeads are mixed into the rubber raw material and mixed uniformly.
  • the rubber material is introduced into the mold cavity; next, the mold cavity is heated, and at a set temperature, the foamed microspheres expand in volume after being heated to form micropores in the rubber material.
  • the particle size of the foamed microbeads ranges from 0.05 ⁇ m to 100 ⁇ m, and the cell size refers to the distance between the two largest points of the cell.
  • the initial temperature of foamed microbeads is 90°C ⁇ 230°C.
  • the foamed microbeads have good dispersibility within the above size range and can be uniformly dispersed in the rubber material.
  • the more preferable range is 0.05 ⁇ m to 50 ⁇ m, and the foamed microbeads are more easily dispersed.
  • the expansion temperature is much lower than the vulcanization temperature of the rubber material, which will cause the internal cell size of the rubber material to be small or even non-existent during the molding process.
  • the initial expansion temperature of the foamed microbeads should be close to, or even the same as, the vulcanization temperature of the rubber material, so as to ensure that the foamed microbeads can form cells.
  • Supercritical foam molding is a physical foam molding technology as well as a microcellular foam molding technology.
  • a foaming agent such as carbon dioxide or nitrogen in a supercritical state into a closed container, so that the foaming agent and the molten copolymer are sufficiently uniformly mixed and diffused to form a single-phase mixed sol;
  • the sol is introduced into the mold cavity or the extrusion die, so that the sol generates a large pressure drop, so that the gas is precipitated to form a large number of bubble nuclei.
  • the bubble core inside the sol continuously grows and forms, and finally a foam is obtained.
  • the foam produced by the supercritical foaming molding method can improve warpage deformation, eliminate surface sink marks, and can make the foamed rubber formed into a good shape, which is beneficial to the production of a relatively flat foamed rubber film layer.
  • the addition amount of the blowing agent can be controlled to be 0.1 wt% to 20 wt%. Further, the addition amount of the blowing agent can be controlled to be 1wt% to 15wt%.
  • the foamed microbeads when the content of the foamed microbeads is less than 10%, as the content of the foamed microbeads increases, the average size of the cells formed on the foamed rubber basically maintains No change, and the density of foamed rubber gradually decreases.
  • the content of foamed microbeads exceeds 15%, the foam cells on the foamed rubber will show a tendency to become larger, and the density of the material will be significantly reduced. This is due to the large content of foamed microbeads, In the foam rubber molding process, small-sized cells gather together to form large-sized cells.
  • Table 1 shows the relationship between the content of foamed microbeads and the cell size and density on the foam. It can be seen from Table 1 that as the content of foamed microbeads (blowing agent) increases, the size of the cells on the foam increases and the density of the foam decreases.
  • Table 1 The relationship between the content of foamed microbeads and cell size and density
  • the prepared foam rubber has a cell size of 10 ⁇ m to 300 ⁇ m. Within this range, the cells can effectively reduce the density of the material and maintain good structural strength, resilience and temperature resistance.
  • the size of the cells is 20 ⁇ m to 200 ⁇ m. Within this range, the physical properties of the material are better.
  • the size of the cells on the foam has a positive correlation with the content of the blowing agent.
  • the content of foaming agent is small, the arrangement of cells and cells on the formed foam is relatively loose, cell walls are thicker, and cell size changes are small.
  • the content of the foaming agent is high, the cells are closely arranged on the formed foam, which will make the cell wall thinner, and there may be a gap between the cells and the cells.
  • the phenomenon of phase fusion which will cause the cell size to increase and the density to decrease. Therefore, the size of the cells on the foam should be reasonably controlled.
  • the density of the foamed rubber is 0.1 g/cm 3 to 1.2 g/cm 3
  • the porosity is 10% to 90%.
  • the porosity is inversely proportional to the density of the elastomer material. The higher the porosity, the lower the density of the elastomer material.
  • the main factor affecting the density of the material is the amount of foaming agent added.
  • a too low density will result in a decrease in the mechanical strength of the material.
  • the diaphragm is easy to crack, and it is difficult to meet the needs of use. Within the above range, the density of the diaphragm is moderate, the mechanical performance is high, cracking is not easy to occur, and the overall performance of the diaphragm is good.
  • the density of the foamed rubber is 0.2 g/cm 3 to 1.0 g/cm 3 , and the porosity is 20% to 80%. Within this range, the foamed rubber has good resilience performance, low density, and the manufactured diaphragm has a large amplitude and low polarization.
  • the density of the foamed rubber is 0.1 g/cm 3 to 1.1 g/cm 3 .
  • the diaphragm made of the foamed rubber can have a smaller mass, so that the sound device exhibits a higher loudness.
  • Fig. 1 is an SPL curve of a diaphragm and a conventional rubber diaphragm according to an embodiment of the present disclosure.
  • the abscissa is the frequency, the unit: Hz; the ordinate is the loudness, the unit: dB.
  • the solid line is the test curve of the diaphragm of an embodiment of the disclosure.
  • the dotted line is the test curve of the conventional rubber diaphragm.
  • the two kinds of diaphragms are both folded ring diaphragms, and the sizes of the two kinds of diaphragms are the same.
  • the low-frequency performance of the two diaphragms is similar.
  • the F0 of the sounding device using the diaphragm and the rubber diaphragm of the embodiment of the present disclosure are both 193 Hz.
  • the frequency sensitivity of the sound device using the diaphragm of the embodiment of the present disclosure is about 1.6 dB higher than that of the rubber diaphragm. It can be seen that the sound device adopting the diaphragm of the embodiment of the present disclosure has higher loudness and comfort.
  • the elongation at break of the foamed rubber is ⁇ 100%. If the elongation at break is ⁇ 100%, the diaphragm is less likely to have reliability problems such as membrane rupture in the use of the module.
  • the elongation at break of the foamed rubber is greater than or equal to 100%, which makes the vibration displacement of the diaphragm of the manufactured sound device larger and louder. Moreover, the reliability and durability are good, and the flexibility of the material is better. The greater the elongation at break, the stronger the ability of the diaphragm to resist damage.
  • the elongation at break of the foamed rubber is greater than or equal to 150%, which makes the vibration displacement of the diaphragm of the manufactured sound device larger and louder.
  • the foamed rubber has good flexibility and high elongation at break, which makes the made diaphragm strong against damage. Even when the diaphragm is vibrating in a state of large amplitude, due to its good flexibility, the risk of damage to the diaphragm can be significantly reduced, and the service life of the diaphragm is increased.
  • the tensile strength of the foamed rubber is 0.1 MPa-50 MPa. Further, the tensile strength of the foamed rubber is 0.1 MPa to 35 MPa.
  • the elastic recovery rate of the foamed rubber film layer after 10% strain is ⁇ 80%. Due to the good resilience of the diaphragm, the sound device using the diaphragm has better transient response and lower distortion.
  • the diaphragm provided by the embodiment of the present invention has the characteristic of higher damping. In this way, the vibration system has a strong ability to suppress the polarization phenomenon of the diaphragm during the vibration process, and the vibration consistency is good.
  • the diaphragm made of foam rubber has a wider elastic area, and the strain occurs in this area.
  • the material has excellent resilience. In this way, the diaphragm is in the vibration process. , Less rocking vibration, better sound quality and listening stability of the sounding device.
  • Fig. 2 is a total harmonic distortion (THD) curve of a diaphragm and a conventional rubber diaphragm according to an embodiment of the present disclosure.
  • THD total harmonic distortion
  • the abscissa is frequency, the unit is Hz; the ordinate is THD.
  • the solid line is the test curve of the diaphragm provided by the embodiment of the disclosure.
  • the dotted line is the test curve of the conventional rubber diaphragm (non-foamed diaphragm). Both diaphragms are cones and have the same size.
  • the total harmonic distortion of the diaphragm of the embodiment of the present disclosure is basically the same, and there is no spike or the like. This shows that, while the quality of the speaker diaphragm of the embodiment of the present disclosure is reduced, the anti-polarization ability is not reduced, and the sound quality is still relatively excellent.
  • the thickness of the foamed rubber film layer may range from 50 ⁇ m to 2000 ⁇ m.
  • the greater the thickness of the foamed rubber membrane layer the smaller the vibration space margin of the formed vibration system, and the increase in the mass of the vibration system at the same time makes the sensitivity of the vibration system worse.
  • the smaller the thickness of the foamed rubber membrane layer the insufficient rigidity of the formed diaphragm, so that the polarization of the diaphragm is likely to occur during the vibration of the diaphragm.
  • the diaphragm can have both good sounding sensitivity and high structural strength.
  • the thickness of the foamed rubber film layer is 100 ⁇ m to 1200 ⁇ m. Within this thickness range, it helps to increase the sensitivity of the diaphragm. Under the same driving power, the diaphragm has a large amplitude and loudness, and the vibration space of the vibration system is larger. The overall performance of the diaphragm is more excellent, which is more conducive to improving the performance of the sound device.
  • the diaphragm provided by the embodiment of the present invention may have a single-layer structure or a multi-layer composite structure.
  • the diaphragm is a single-layer diaphragm, and the single-layer diaphragm is composed of a layer of foamed rubber film.
  • the structure of the diaphragm is relatively simple.
  • the diaphragm is a composite diaphragm.
  • the composite diaphragm may include two, three, four or five film layers, and the composite diaphragm includes at least one foam rubber film layer.
  • foam rubber film layer For other film layers, those skilled in the art can flexibly choose suitable materials for production according to actual needs, and there is no restriction on this.
  • the diaphragm may also include an adhesive film layer.
  • the adhesive film layer can provide the damping and cohesiveness required by the diaphragm.
  • the adhesive film layer can be directly bonded with the foamed rubber film layer to form a composite structure.
  • the adhesive force between the foamed rubber film layer and the adhesive film layer is greater than 50 g/25 mm. Within this range, the overall strength and durability of the diaphragm can be significantly improved.
  • the adhesive force between the foamed rubber film layer and the adhesive film layer is greater than 100 g/25 mm.
  • the high adhesion force makes the diaphragm and the cone in the vibration process good coordination and consistency, the sound quality is pure, and the diaphragm still maintains the initial state after long-term vibration, and the performance stability is high.
  • the adhesive film layer may be selected from one or more of acrylic adhesives, silicone adhesives and polyurethane adhesives.
  • the adhesive force and damping performance of the above-mentioned adhesive film layer are good. Those skilled in the art can make selections according to actual needs.
  • the thickness of the adhesive film layer can be controlled within 1 ⁇ m-40 ⁇ m, for example.
  • the adhesive force of the adhesive film layer will increase as its thickness increases. If the thickness of the rubber film layer is too small, it may cause insufficient adhesion, and cannot effectively ensure the consistency of the movement of the upper and lower surface layers of the rubber film layer during the vibration of the diaphragm. At the same time, the damping effect provided by the film layer will also decrease as the thickness decreases.
  • the thickness of the film layer is too large, on the one hand, it will reduce the vibration space margin; on the other hand, the edge of the diaphragm is prone to problems such as glue overflow.
  • the adhesive film layer in the above thickness range can take into account sufficient adhesion, excellent damping effect, and sufficient vibration space margin for the vibration system.
  • the diaphragm has a three-layer composite structure, as shown in FIG.
  • the diaphragm of this structure has the characteristics of strong rigidity and good damping effect.
  • Both surface layers are foamed rubber membrane layer 1, which makes the produced diaphragm have the characteristics of good hardness, toughness and resilience.
  • the materials of the two surface layers of the diaphragm are uniform, the durability of the diaphragm is more excellent.
  • the diaphragm is a four-layer composite structure, which includes two middle layers and two surface layers; wherein, the two surface layers are both foamed rubber film layers 1, and The two intermediate layers can be two glue film layers of different materials.
  • the diaphragm of this structure has the characteristics of strong rigidity and good damping effect.
  • the diaphragm has a five-layer composite structure, which includes three intermediate layers and two surface layers; both surface layers are foamed rubber membrane layers 1; wherein, the two intermediate layers are both It is the adhesive film layer 2, and another intermediate layer is sandwiched between the two intermediate layers, and the foamed rubber film layer 1 is used.
  • the foamed rubber film layer 1 and the glue film layer 2 are alternately arranged with each other.
  • the diaphragm of this structure has strong rigidity, good damping effect, and excellent resilience.
  • the materials of the two surface layers are the same, and the thickness is also the same, which makes the formed diaphragm have good uniformity and is not easy to curl or wrinkle.
  • the material of the two surface layers is not limited to the same.
  • the materials of the two surface layers are different. Only one of the surface layers uses a foamed rubber film layer, and the other surface layer is a film layer of other materials.
  • the specific film layer material can be flexibly selected by those skilled in the art according to actual needs. Then, a plurality of film layers are bonded together by, for example, an adhesive film layer.
  • the diaphragm made in this way also has good physical and acoustic properties.
  • the diaphragm in the embodiment of the present invention is, for example, a folded ring diaphragm or a flat diaphragm.
  • a sound generating device includes a vibration system and a magnetic circuit system that cooperates with the vibration system.
  • the vibration system includes the diaphragm described in any of the above embodiments.
  • the sound generating device may be a horn device.
  • the sound generating device has the characteristics of high loudness, high sensitivity, low distortion and good durability.
  • the sound generating device provided by the embodiment of the present invention has the characteristics of good sounding effect and good durability.

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Abstract

一种振膜以及发声装置，所述振膜包括发泡橡胶制成的发泡橡胶膜层（1）；其中，所述发泡橡胶为通过发泡法制备的发泡体；所述发泡橡胶的泡孔的尺寸为10μm～300μm；所述发泡橡胶的玻璃化转变温度≤-10℃；所述发泡橡胶的密度为0.1g/cm3～1.2g/cm3。发泡橡胶由于在材料的内部均匀地分布有泡孔，故使得材料的整体密度降低，相同尺寸的振膜的重量降低，制成的振膜的回弹性能良好。

Description

一种振膜以及发声装置 技术领域
本发明涉及电声转换技术领域，更具体地，本发明涉及一种振膜以及发声装置。
背景技术
随着电声技术的飞速发展，各种类型的电声产品层出不穷。发声装置作为一种将电信号转换为声音信号的能量转换器，是电声产品中不可缺少的器件。发声装置已经被应用于手机、平板电脑、笔记本电脑、导航仪、电子书以及智能可穿戴设备等多种不同类型的终端电子产品中，其应用非常广泛。
振膜被设置在发声装置的振动系统中，其是发声装置中较为重要的部件之一。目前，发声装置振膜多采用橡胶膜层(例如，丁腈橡胶NBR、丁基橡胶IIR等)制作。但是，上述的振膜，其综合性能都比较差，例如密度大、弹性回复率低、耐热性能差等，导致发声装置振膜的响度低、高低温循环可靠性余量小。这种发声装置振膜无法满足发声装置的高功率化、防水以及高音质的要求。
因此，需要提供一种新的技术方案，以解决上述技术问题。
发明内容
本发明的一个目的是提供一种振膜的新技术方案。
根据本发明的第一方面，提供了一种振膜，所述振膜包括发泡橡胶制成的发泡橡胶膜层；
其中，所述发泡橡胶为通过发泡法制备的发泡体；
所述发泡橡胶的泡孔的尺寸为10μm～300μm；
所述发泡橡胶的玻璃化转变温度≤-10℃；
所述发泡橡胶的密度为0.1g/cm 3～1.2g/cm 3。
可选地，所述发泡橡胶是三元乙丙橡胶、氢化丁腈橡胶、乙烯-丙烯酸酯橡胶、丙烯酸酯橡胶、丁苯橡胶、天然橡胶、丁腈橡胶、丁基橡胶、聚氨酯橡胶、异戊橡胶、顺丁橡胶、醋酸乙烯酯橡胶、聚硫橡胶和氟橡胶中的至少一种。
可选地，所述发泡法采用发泡剂，所述发泡剂为发泡微珠、偶氮化合物、亚硝基化合物、无机系化合物、联胺类化合物、二氧化碳、氮气和丁烷中的至少一种。
可选地，所述发泡剂的添加量为0.1wt％～20wt％。
可选地，所述发泡橡胶的断裂伸长率≥100％。
可选地，所述发泡橡胶的拉伸强度为0.1MPa～50MPa。
可选地，所述发泡橡胶的孔隙率为10％～90％。
可选地，所述发泡橡胶膜层10％应变后的弹性回复率≥80％。
可选地，所述振膜为单层振膜，且所述单层振膜采用一层发泡橡胶膜层制成；或者，
所述振膜为复合振膜，所述复合振膜包括两层、三层、四层或五层膜层，所述复合振膜至少包括一层发泡橡胶膜层。
可选地，还包括胶膜层；
在180°剥离测试中，所述胶膜层与所述发泡橡胶膜层之间的粘着力大于50g/25mm。
可选地，所述发泡橡胶膜层的厚度为50μm～2000μm。
根据本发明的第二方面，提供了一种发声装置。所述发声装置包括振动系统和与所述振动系统相配合的磁路系统；
其中，所述振动系统包括上述的振膜。
根据本公开的一个实施例，发泡橡胶膜层由于在材料的内部均匀地分布有泡孔，故可使材料的整体密度降低，与相同尺寸的常规橡胶振膜相比，可使振膜的重量明显降低。而且，采用发泡橡胶制成的振膜回弹性良好，从而可使发声装置表现出较高的音质。
通过以下参照附图对本发明的示例性实施例的详细描述，本发明的其它特征及其优点将会变得清楚。
附图说明
被结合在说明书中并构成说明书的一部分的附图示出了本发明的实施例，并且连同其说明一起用于解释本发明的原理。
图1是根据本公开的一个实施例的振膜与常规橡胶振膜的不同频率下响度的测试曲线(SPL曲线)。
图2是根据本公开的一个实施例的振膜与常规的橡胶振膜的谐波失真(Total Harmonic Distortion，THD)曲线。
图3是根据本公开的一个实施例提供的振膜的剖视图。
具体实施方式
现在将参照附图来详细描述本发明的各种示例性实施例。应注意到：除非另外具体说明，否则在这些实施例中阐述的部件和步骤的相对布置、数字表达式和数值不限制本发明的范围。
以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本发明及其应用或使用的任何限制。
对于相关领域普通技术人员已知的技术、方法和设备可能不作详细讨论，但在适当情况下，所述技术、方法和设备应当被视为说明书的一部分。
在这里示出和讨论的所有例子中，任何具体值应被解释为仅仅是示例性的，而不是作为限制。因此，示例性实施例的其它例子可以具有不同的值。
应注意到：相似的标号和字母在下面的附图中表示类似项，因此，一旦某一项在一个附图中被定义，则在随后的附图中不需要对其进行进一步讨论。
根据本发明的一个实施例，提供了一种振膜，该振膜可应用在例如大型喇叭、小型喇叭等发声装置中，可使发声装置表现出较高的音质。该振膜可以是但不限于锥形或者平板形。此外，该振膜可以为单层结构，或者是由多个膜层的复合而成的复合结构，本领域技术人员可以根据需要灵活调整，本发明对此不作限制。
本发明实施例提供的振膜，其包括采用发泡橡胶制成的发泡橡胶膜层。
其中，所述发泡橡胶为三元乙丙橡胶、氢化丁腈橡胶、乙烯-丙烯酸酯橡胶、丙烯酸酯橡胶、丁苯橡胶、天然橡胶、丁腈橡胶、丁基橡胶、聚氨酯橡胶、异戊橡胶、顺丁橡胶、醋酸乙烯酯橡胶、聚硫橡胶和氟橡胶中的至少一种，通过发泡法制备而成的发泡体。
所述发泡橡胶的玻璃化转变温度≤-10℃。玻璃化转变温度越高，分子链段的刚性就越大，材料力学强度越大，弹性回复率越差。在本发明实施例中，所述发泡橡胶的玻璃化转变温度≤-10℃。该玻璃化转变温度，使得该振膜在常温下能够保持高弹态，回弹性良好。
而更为优选的是，所述发泡橡胶的玻璃化转变温度为-80℃～-30℃。这使得在低于-20℃的环境中，振膜工作时可以一直保持较好的弹性，从而使应用该振膜的发声装置能够表现出较高的音质。同时，降低了在低温环境中发声装置振膜破坏的风险，可使振膜的可靠性更高。
本发明实施例的振膜，能够满足发声装置(例如，喇叭)对高、低温环境使用的需求。低温性能较常规的振膜(例如，PEEK振膜)突出。即使在低温环境下使用，本发明实施例提供的振膜仍具有良好的结构强度和韧性。在长时间低温环境中，振膜振动破膜风险低，可靠性高，非常适合推广使用。
本发明实施例中，在制备振膜时采用的材料是发泡橡胶。发泡橡胶制成的膜层，由于在其材料的内部均匀地分布有泡孔(气泡)，故可使材料的整体密度降低，相同尺寸的振膜的重量降低。这使得材料的回弹性能更好，振幅更大、更不易因自身的重量导致振膜发生形变。
本发明实施例中采用发泡法制得发泡橡胶。发泡法包括化学发泡法或者物理发泡法。其中，化学发泡法是指利用化学方法产生气体来使弹性体材料(例如塑料)发泡的方法。加入弹性体材料中的化学发泡剂加热后发生分解，从而释放出气体，该气体在弹性体成型过程中形成气泡。也可以是，利用弹性体材料的不同组分之间相互发生化学反应释放出的气体而在弹性体材料成型过程中进行发泡。
物理发泡法是指通过材料中加入的发泡剂的物理变化，在材料成型过 程中使材料内形成气泡的方法。物理发泡法不会对弹性体材料的化学性能、分子结构造成影响，并且能够在材料的内部形成均匀地气泡。
本领域技术人员可以根据实际需要选择发泡方法和发泡剂。
在本发明的一个例子中，所述发泡橡胶在制备中所采用的发泡剂为发泡微珠、偶氮化合物、亚硝基化合物、无机系化合物、联胺类化合物、二氧化碳、氮气和丁烷中的至少一种。上述的这些发泡剂均能在材料内部形成均匀的泡孔(气泡)。而且，上述列举的发泡剂成本比较低廉，且绿色环保，非常适合在工业上大批量生产。在具体的应用中，本领域技术人员可以根据实际需要灵活进行选择。
以发泡剂采用发泡微珠为例。发泡微珠为中空的微米级球体，其材质为树脂等。在制备时，首先，发泡微珠被混合到橡胶原料中，并混合均匀。然后，橡胶原料被导入模具型腔内；接下来，对模具型腔进行加热，在设定的温度下，发泡微珠受热后体积膨胀，在橡胶材料中形成微孔。发泡微珠的粒径尺寸范围为0.05μm～100μm，其中泡孔尺寸指泡孔最大的两点之间的距离。发泡微珠受热膨胀初始温度为90℃～230℃。在发泡微珠的粒径尺寸较大时，其在橡胶中分散均匀性变差，易造成泡孔不均匀。在上述尺寸范围内发泡微珠的分散性良好，能够均匀地分散在橡胶材料中。
而较为优选的范围是0.05μm～50μm，发泡微珠更容易被分散。
例如，膨胀温度远低于橡胶材料的硫化温度会造成在模压过程中，橡胶材料内部泡孔尺寸较小甚至不存在泡孔的现象。优选地，发泡微珠的初始膨胀温度应与橡胶材料的硫化温度接近，甚至相同，从而保证发泡微珠能够形成泡孔。
还可以是，采用超临界发泡的方式形成发泡橡胶。超临界发泡成型是一种物理发泡成型技术，同时也是一种微孔发泡成型技术。在制备时，首先，将超临界状态的二氧化碳或氮气等发泡剂注入到密闭容器中，使发泡剂与熔融态共聚物充分均匀混合、扩散后，形成单相混合溶胶；然后，将该溶胶导入模具型腔或挤出口模，使溶胶产生大的压力降，从而使气体析出，以形成大量的气泡核。在随后的冷却成型过程中，溶胶内部的气泡核不断长大成型，最终获得发泡体。通过超临界发泡成型法制得的发泡体， 可改善翘曲变形，消除表面缩痕，可使制成的发泡橡胶外形良好，有利于制作成较为平整的发泡橡胶膜层。
此外，利用超临界发泡成型法制成发泡体时，可供选择使用的发泡剂种类较多，可以简化生产，降低生产难度。
本发明实施例中，所述发泡剂的添加量可以控制为0.1wt％～20wt％。进一步地，所述发泡剂的添加量可以控制为1wt％～15wt％。
本发明实施例中，以发泡微珠为例，当发泡微珠的含量低于10％时，随着发泡微珠含量增加，形成在发泡橡胶上的泡孔的平均尺寸基本保持不变，且发泡橡胶密度逐渐降低。而当发泡微珠的含量超过15％时，发泡橡胶上的泡孔则会呈现出变大的趋势，并且使材料的密度显著降低，这是由于发泡微珠含量较大，在发泡橡胶成型过程中小尺寸的泡孔聚集在一起形成大尺寸的泡孔。
表1为发泡微珠含量与发泡体上泡孔尺寸及密度的关系。由表1可以看出，随着发泡微珠(发泡剂)含量增多，发泡体上泡孔的尺寸增加，发泡体密度降低。
表1发泡微珠含量与泡孔尺寸及密度的关系
Figure PCTCN2020136207-appb-000001
在本发明实施例中，制备出的发泡橡胶，其上泡孔的的尺寸为10μm～300μm。在该范围内，泡孔能有效地降低材料的密度，并保持良好的结构强度、回弹性能和耐温性能。
进一步地，泡孔的的尺寸为20μm～200μm。在该范围内，材料的物理性能更加良好。
发泡体上泡孔的尺寸与发泡剂的含量具有正相关性。当发泡剂含量较少时，在形成的发泡体上、泡孔与泡孔之间排列的较为疏松，泡孔壁较厚，泡孔尺寸变化较小。而当发泡剂含量较高时，在形成的发泡体上、泡孔与泡孔之间呈紧密排列，这会使得泡孔壁变薄，并且可能会出现泡孔与泡孔 之间的相融合现象，这将会导致泡孔的尺寸增加，密度降低。因此，对于发泡体上的泡孔的尺寸应当合理控制。
在本发明实施例中，所述发泡橡胶的密度为0.1g/cm 3～1.2g/cm 3，孔隙率为10％～90％。孔隙率与弹性体材料的密度成反比关系，孔隙率越高，则弹性体材料的密度越小。
在发泡体中，材料密度的影响因素主要是发泡剂的添加量。发泡剂的含量越高，则发泡倍率越大，材料的密度越低。而过低的密度会导致材料力学强度降低。在使用过程中，振膜易开裂，难以满足使用需求。在上述范围内，振膜的密度适中，力学性能高，不易产生开裂，振膜的综合性能良好。
进一步地，所述发泡橡胶的密度为0.2g/cm 3～1.0g/cm 3，孔隙率为20％～80％。在该范围内，所述发泡橡胶的回弹性能良好，密度小，制成的振膜的振幅大，偏振小。
而较为优选的是，所述发泡橡胶的密度为0.1g/cm 3～1.1g/cm 3。在该密度下，相较于常规的橡胶振膜，所述发泡橡胶制备的振膜可以具有更小的质量，从而使发声装置表现出较高的响度。
图1是根据本公开的一个实施例的振膜与常规橡胶振膜的SPL曲线。在图1中：横坐标为频率，单位：Hz；纵坐标为响度，单位：dB。实线为本公开的一个实施例的振膜的测试曲线。虚线为常规橡胶振膜的测试曲线。其中，两种振膜都为折环振膜，且两种振膜的尺寸相同。
如图1所示，由SPL曲线可以看出，两个振膜低频性能相近。而采用本公开实施例的振膜和橡胶振膜的发声装置的F0均为193Hz。但采用本公开实施例的振膜的发声装置的频灵敏度高于橡胶振膜约1.6dB。可见，采用本公开实施例的振膜的发声装置具有更高的响度和舒适度。
在本发明实施例中，所述发泡橡胶的断裂伸长率≥100％。断裂伸长率≥100％，则振膜在模组使用中，不易出现破膜等可靠性问题。
此外，所述发泡橡胶的断裂伸长率≥100％，这使得制成的发声装置振膜的振动位移更大，响度更大。并且，可靠性、耐用性良好，材料的柔韧性越好。断裂伸长率越大，则振膜抵抗破坏的能力越强。
进一步地，所述发泡橡胶的断裂伸长率≥150％，这使得制成的发声装置振膜的振动位移更大，响度更大。
发泡橡胶柔韧性较好，断裂伸长率较大，使得制成的振膜抵抗破坏的能力强。即使在振膜处于大振幅状态下振动时，基于其具有良好的柔韧性，可明显降低振膜破坏的风险，提高了振膜的使用寿命。
在本发明实施例中，所述发泡橡胶的拉伸强度为0.1MPa～50MPa。进一步地，所述发泡橡胶的拉伸强度为0.1MPa～35MPa。
与材料的拉伸强度相关量存在有两个，具体来说：(1)分子链的刚性越大，材料的玻璃化转变点越高，材料的耐低温性能变差，材料的强度升高，断裂伸长率降低。(2)发泡倍率升高，材料的密度降低，孔隙率升高，材料的强度降低，断裂伸长率适度下降。
在本发明实施例中，所述发泡橡胶膜层在10％应变后的弹性回复率≥80％。由于振膜的回弹性良好，故使得使用该振膜的发声装置具有较好的瞬态响应和较低的失真。
本发明实施例提供的振膜，相比于常规的振膜，其具有阻尼性较高的特点。这样，振动系统在振动过程中可抑制振膜偏振现象的能力较强，振动一致性良好。
相对于传统的橡胶振膜，采用发泡橡胶制备的振膜具有较宽的弹性区域，发生在该区域的应变，当外力去除后，材料具有优异的回复性，这样，振膜在振动过程中，摇摆振动少，发声装置的音质和听音稳定性更优。
图2是根据本公开的一个实施例的振膜与常规橡胶振膜的总谐波失真(Total Harmonic Distortion，THD)曲线。其中，横坐标为频率，单位：Hz；纵坐标为THD。实线为本公开实施例提供的振膜的测试曲线。虚线为常规橡胶振膜(非发泡振膜)的测试曲线。两种振膜均为锥盆，尺寸相同。
由图2可以看出，本公开实施例的振膜与常规橡胶振膜相比，总谐波失真基本一致，并且无尖峰等。这表明，本公开实施例的扬声器振膜在降低质量的同时抗偏振能力并没有降低，音质依然较为优异。
在本发明的一个例子中，所述发泡橡胶膜层的厚度范围可以为50μm～2000μm。所述发泡橡胶膜层的厚度越大，形成的振动系统的振动空 间余量变小，同时振动系统的质量增加，使得振动系统的灵敏度变差。所述发泡橡胶膜层的厚度越小，形成的振膜的刚度不足，这样在振膜振动的过程中容易发生振膜偏振的现象。在上述的厚度范围内，可使振膜兼具良好的发音灵敏度和高的结构强度。
进一步地，所述发泡橡胶膜层的厚度为100μm～1200μm。在该厚度范围内，有助于使振膜的灵敏度变得更高，同样地驱动功率下，振膜的振幅大、响度大，并且使振动系统的振动空间余量更大。振膜的综合性能更加优良，更加有利于提高发声装置的性能。
本发明实施例提供的振膜可以为单层结构，也可以为多层复合结构。
例如，所述振膜为单层振膜，且所述单层振膜采用一层发泡橡胶膜层构成。该振膜的结构较为简单。
或者，所述振膜为复合振膜。所述复合振膜可以包括两层、三层、四层或五层膜层，所述复合振膜至少包括一层发泡橡胶膜层。而对于其他的膜层本领域技术人员可以根据实际需要灵活选择合适的材料制作，对此不作限制。
此外，所述振膜还可以包括胶膜层。而对于复合振膜而言，胶膜层可用以提供振膜所需的阻尼性和粘结性。胶膜层可直接与发泡橡胶膜层粘结在一起，从而形成复合结构。
其中，在180°剥离测试下，所述发泡橡胶膜层与胶膜层之间的粘接力大于50g/25mm。在该范围内可使振膜的整体的强度、耐用性显著提高。
进一步地，在180°剥离测试下，所述发泡橡胶膜层与所述胶膜层之间的粘接力大于100g/25mm。在应用在发声装置中时，粘结力高使振膜在振动过程中与锥盆的协调一致性良好，音质纯正，且在长时间振动后振膜仍然保持初始状态，性能稳定性高。
此外，所述胶膜层可选自丙烯酸脂类胶黏剂、有机硅胶黏剂和聚氨酯胶黏剂中的一种或多种。上述胶膜层的粘结力和阻尼性能良好。本领域技术人员可以根据实际需要进行选择。胶膜层的厚度例如可控制在1μm-40μm。胶膜层的粘结力会随着其厚度的增加而增大。胶膜层的厚度太小，可能会造成粘结力不足，在振膜振动的过程中无法有效的保证胶膜层上、下的表层的运动的一致 性。同时，胶膜层提供的阻尼效果也会随着厚度的降低而减小。胶膜层的厚度太大，一方面会降低振动空间余量；另一方面振膜的边缘易出现溢胶等问题。上述厚度范围的胶膜层能兼顾足够的粘结力、优良的阻尼效果以及使振动系统具有充足的振动空间余量。
以下以几种多层复合结构的振膜为例，对其结构进行说明。
在本发明的一个具体实施方式中，所述振膜为三层复合结构，如图3所示，其包括一个中间层和两个表层；其中，中间层为胶膜层2，两个表层均为发泡橡胶膜层1。该结构的振膜具有刚度强和阻尼效果良好的特点。两个表层均为发泡橡胶膜层1，这使得制成的振膜具有硬度、韧性和回弹性好的特点。而且，由于振膜的两个表层的材质均一，故使得振膜的耐用性更加优良。
在本发明的一个具体实施方式中，所述振膜为四层复合结构，其包括有两个中间层和两个表层；其中，所述两个表层均为发泡橡胶膜层1，所述两个中间层可以为两种不同材料的胶膜层。该结构的振膜具有刚度强，以及阻尼效果良好的特点。
在本发明的一个具体实施方式中，所述振膜为五层复合结构，其包括有三个中间层和两个表层；两个表层均为发泡橡胶膜层1；其中，两个中间层均为胶膜层2，而另外一个中间层夹在这两个中间层之间，且采用的是发泡橡胶膜层1。在该振膜结构中，发泡橡胶膜层1和胶膜层2为相互交替排列。该结构的振膜刚度强，阻尼效果良好，回弹性也较为优异。
在上述的三个具体实施方式中，两个表层的材料相同，且厚度也是相同的，这使得形成的振膜的均一性良好，并且不容易卷曲、褶皱。
此外，在其他的实施例中，并不限于两个表层的材质相同。
还可以是，两个表层的材质不同，仅其中的一个表层采用发泡橡胶膜层，而另一个表层为其他材料膜层，具体的膜层材料本领域技术人员可以根据实际需要灵活选择。再通过例如胶膜层将多个膜层粘结在一起。这种方式制成的振膜也具备良好的物理和声学性能。
本发明实施例的振膜例如为折环振膜或者平板振膜。
根据本发明的另一个实施例，提供了一种发声装置。所述发声装置包括振动系统和与振动系统相互配合的磁路系统。其中，所述振动系统包括上述任 一实施例中所述的振膜。所述发声装置可以为喇叭装置。
该发声装置具有响度高、灵敏度高、失真小、耐用性良好的特点。
本发明实施例提供的发声装置具有发声效果好，耐用性良好的特点。
上文实施例中重点描述的是各个实施例之间的不同，各个实施例之间不同的优化特征只要不矛盾，均可以组合形成更优的实施例，考虑到行文简洁，在此则不再赘述。
虽然已经通过例子对本发明的一些特定实施例进行了详细说明，但是本领域的技术人员应该理解，以上例子仅是为了进行说明，而不是为了限制本发明的范围。本领域的技术人员应该理解，可在不脱离本发明的范围和精神的情况下，对以上实施例进行修改。本发明的范围由所附权利要求来限定。

Claims (12)

  1. 一种振膜，其特征在于：包括发泡橡胶制成的发泡橡胶膜层；
    其中，所述发泡橡胶为通过发泡法制备的发泡体；
    所述发泡橡胶的泡孔的尺寸为10μm～300μm；
    所述发泡橡胶的玻璃化转变温度≤-10℃；
    所述发泡橡胶的密度为0.1g/cm 3～1.2g/cm 3。
  2. 根据权利要求1所述的振膜，其特征在于：所述发泡橡胶是三元乙丙橡胶、氢化丁腈橡胶、乙烯-丙烯酸酯橡胶、丙烯酸酯橡胶、丁苯橡胶、天然橡胶、丁腈橡胶、丁基橡胶、聚氨酯橡胶、异戊橡胶、顺丁橡胶、醋酸乙烯酯橡胶、聚硫橡胶和氟橡胶中的至少一种。
  3. 根据权利要求1所述的振膜，其特征在于：所述发泡法采用发泡剂，所述发泡剂为发泡微珠、偶氮化合物、亚硝基化合物、无机系化合物、联胺类化合物、二氧化碳、氮气和丁烷中的至少一种。
  4. 根据权利要求3所述的振膜，其特征在于：所述发泡剂的添加量为0.1wt％～20wt％。
  5. 根据权利要求1所述的振膜，其特征在于：所述发泡橡胶的断裂伸长率≥100％。
  6. 根据权利要求1所述的振膜，其特征在于：所述发泡橡胶的拉伸强度为0.1MPa～50MPa。
  7. 根据权利要求1所述的振膜，其特征在于：所述发泡橡胶的孔隙率为10％～90％。
  8. 根据权利要求1所述的振膜，其特征在于：所述发泡橡胶膜层10％应变后的弹性回复率≥80％。
  9. 根据权利要求1所述的振膜，其特征在于：所述振膜为单层振膜，且所述单层振膜采用一层发泡橡胶膜层制成；或者，
    所述振膜为复合振膜，所述复合振膜包括两层、三层、四层或五层膜层，所述复合振膜至少包括一层发泡橡胶膜层。
  10. 根据权利要求1所述的振膜，其特征在于：还包括胶膜层；
    在180°剥离测试中，所述胶膜层与所述发泡橡胶膜层之间的粘着力大于50g/25mm。
  11. 根据权利要求1所述的振膜，其特征在于：所述发泡橡胶膜层的厚度为50μm～2000μm。
  12. 一种发声装置，其特征在于：包括振动系统和与所述振动系统相配合的磁路系统；
    其中，所述振动系统包括如权利要求1-11中任意一项所述的振膜。
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