Membrane and method for producing diaphragm, and composite diaphragm

Abstract

A membrane and a method for producing a diaphragm, and a composite diaphragm are provided. The MCPET material is a MCPET baffle with micropores independent from each other; wherein an average size of the micropore is smaller than or equal to 5 m, a foaming rate of the MCPET baffle is less than 2 times, and a density of the MCPET baffle is less than 300 kg/m3. The MCPET baffle is further processed by means of layered cut to form the membrane that is thinner than the MCPET baffle. At least one surface with micropores is exposed to form a micropore exposed surface. The membrane is heated under a temperature of 130-140 C. to form the diaphragm. The composite diaphragm includes a main diaphragm and an auxiliary diaphragm, wherein the main diaphragm is made of the membrane of the present application. The diaphragm made of the membrane has a superior sound performance.

Claims

1. A membrane for producing a diaphragm, wherein, the membrane is made of MCPET material which is a MCPET baffle with micropores independent from each other; wherein an average size of the micropore is smaller than or equal to 5 m, a foaming rate of the MCPET baffle is less than 2 times, and a density of the MCPET baffle is less than 300 kg/m.sup.3; the MCPET baffle is further processed by means of layered cut to form the membrane thinner than the MCPET baffle being processed with a thickness of the membrane between 0.05-1 mm; and at least one surface with micropores is exposed to form a micropore exposed surface.

2. A method for producing an audio speaker diaphragm using a membrane according to claim 1, comprising: cutting the MCPET baffle with micropores in layers to form the membrane which is thinner than the MCPET baffle being cut and has a thickness of 0.05-1 mm, and heating the membrane under a temperature of 130-140 C. to form the diaphragm; wherein an average size of the micropore is smaller than or equal to 5 m; the micropores are independent from each other; a foaming rate of the MCPET baffle is less than 300 kg/m.sup.3; at least one surface with micropores is exposed to form a micropore exposed surface.

3. The method for producing an audio speaker diaphragm according to claim 2, wherein the entire membrane is heated to form conical diaphragm configurations or dome diaphragm configurations or flat diaphragm configurations with a concave radiating surface; and each diaphragm configuration is further split from the entire diaphragm by means of punching or cutting.

4. The method for producing an audio speaker diaphragm according to claim 2, wherein a forming method of one surface heating or two surface heating is used; when there is only one micropore exposed surface, the surface which is contacted with a mould is micropore non-exposed surface, regardless of using the forming method of one surface heating or two surfaces heating.

5. The method for producing an audio speaker diaphragm according to claim 2, wherein a thickness of the membrane is 0.05-1 mm; a forming method of one surface heating or two surface heating is used; when there is only one micropore exposed surface, the surface which is contacted with a mould is micropore non-exposed surface, regardless of using the forming method of one surface heating or two surfaces heating.

6. An audio speaker composite diaphragm, comprising a main diaphragm and an auxiliary diaphragm, wherein the main diaphragm is made of a MCPET baffle with micropores which are independent from each other and have an average size smaller than or equal to 5 m; a foaming rate of the MCPET baffle is less than 2 times; a density of the MCPET baffle is less than 300 kg/m.sup.3; the MCPET baffle is further cut in layers to form a membrane of the main diaphragm; wherein at least one surface with micropores is exposed to form a micropore exposed surface, and a thickness of the membrane is 0.05-1 mm; the membrane is further heated under a temperature of 130-140 C. to form the main diaphragm; the auxiliary diaphragm is in shape of a circular or an annular; an external diameter of the auxiliary diaphragm is larger than an external diameter of the main diaphragm; and the main diaphragm is superposed on the auxiliary diaphragm and is located at the center of the auxiliary diaphragm.

7. The audio speaker composite diaphragm according to claim 6, wherein when there is only one micropore exposed surface on the membrane, the micropore exposed surface is opposite to a sound transmission direction of the main diaphragm.

8. The audio speaker composite diaphragm according to claim 6, wherein the main diaphragm is a conical diaphragm, a flat diaphragm with a concave radiating surface, or a dome diaphragm.

9. The audio speaker composite diaphragm according to claim 6, wherein an annular connected edge is defined on the main diaphragm; the main diaphragm is superposed onto the auxiliary diaphragm via the annular connected edge; and the main diaphragm and the auxiliary diaphragm are pasted or thermal bonded together to form a composite diaphragm.

10. The audio speaker composite diaphragm according to claim 6, wherein the auxiliary diaphragm is made of paper pulp or polymer material; a stiffening ring is fixed on a cylindrical edge of the auxiliary diaphragm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic figure for cutting a MCPET baffle during a process of producing a membrane for a diaphragm, according to a first preferred embodiment of the application;

(2) FIG. 2 is a microscopic enlarged view of a micropore exposed surface of the membrane for a diaphragm, according to the first preferred embodiment of the application;

(3) FIG. 3 is a schematic figure of a configuration of a diaphragm formed by a thermoforming an entire membrane, according to an audio speaker diaphragm producing method of a second preferred embodiment of the application;

(4) FIG. 4 is a schematic figure of a structure of a dome diaphragm made by the audio speaker diaphragm producing method of the second preferred embodiment using the membrane according to the first preferred embodiment of the application;

(5) FIG. 5 is a schematic figure of a structure of a composite diaphragm formed by the dome diaphragm made by the audio speaker diaphragm producing method of the second preferred embodiment using the membrane according to the first preferred embodiment of the application; and

(6) FIG. 6 is a frequency response curve of an audio speaker, according to the membrane of the application.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(7) The present application will be further described in detail with reference to the preferred embodiments and the accompanying drawings.

(8) Example One: the preferred embodiment provides a membrane for producing a diaphragm. The point is that the membrane is made of the MCPET material. The MCPET material is MCPET baffle 1. The MCPET baffle 1 includes micropores 201 which are independent from each other. An average size of the micropore 201 is smaller than 5 m. A foaming rate of the MCPET baffle 1 is less than 2 times, and a density of the MCPET baffle 1 is less than 300 kg/m.sup.3. In the preferred embodiment, a MCPET-VA baffle is specifically used. As shown in FIG. 1, in the preferred embodiment, a cutter 3 is configured to cut the MCPET baffle 1 in layers to form the membrane 2 which is thinner than the MCPET baffle 1 and has a thickness of 0.05-1 mm. The micropores 201 are exposed on at least one surface of the membrane 2 and thus a micropore exposed surface is formed. Of course, after the top layer of the original MCPET baffle 1 is cut in layers, a membrane 2 newly formed will obviously have the micropores 201 exposed on the two surfaces thereof, if the MCPET baffle 1 is further cut. In this case, the membrane 2 has two micropore exposed surfaces. Since the membrane 2 with one micropore exposed surface already has a good performance, for a thicker membrane 2, two micropore exposed surfaces is benefit for improving the performance of the membrane. In the present application, preferably, the thickness of membrane 2 ranges from 0.05 mm to 0.4 mm. A commercially available plate hierarchical machine can be used as the cutting device for cutting. A frequency response characteristics test is performed for the membrane of the preferred example according to the specification of the standards QZ/LCT-QP140-2007 of Longcheer Holdings. The diaphragm of the audio speaker for the test is made of the membrane 2 of the preferred example and the membrane 2 has the following features: the thickness of the membrane 2 is 0.08 mm; the membrane 2 is made of the MCPET-VA baffle; the average size of the micropore 201 is smaller than 5 m; the foaming rate is 1.8; the density is 235 kg/m.sup.3. And the frequency response curve obtained is shown in FIG. 6.

(9) Example two, the preferred embodiment provides a method for producing an audio speaker diaphragm. As shown in FIGS. 1, 2, 3, the point is that firstly a MCPET baffle 1 with micropores 201 is cut in layers by a cutter 3 to form a membrane 2 thinner than the MCPET baffle 1; wherein the MCPET baffle 1 has the following features: the micropores 201 are independent from each other; an average size of the micropore 201 is smaller than 5 m; a foaming rate of the MCPET baffle is less than 2 times; a density of the MCPET baffle is less than 300 kg/m.sup.3. The device used for layered cutting is the same as that in the example one. In the preferred embodiment, the MCPET-VA baffle is specifically used. In the preferred embodiment, a thickness of the membrane 2 is 0.05-1 mm. At least one surface with micropores 201 is exposed to form a micropore exposed surface. Then the membrane 2 is heated under a temperature of 130-140 C. to form the diaphragm. In the preferred embodiment, as shown in FIG. 3, the entire membrane 2 is heated to form several dome diaphragm configurations 4 on the entire membrane 2. As shown in FIG. 4, each diaphragm configuration 4 is split from the entire membrane 2 by means of punching or cutting to form the diaphragm 5. When there is only one micropore exposed surface, the surface which is contacted with a mould is micropore non-exposed surface regardless of using the forming method of one surface heating or two surfaces heating.

(10) Example three: it is specially noted that in the following presentation, the diaphragm 5 is also called main diaphragm 5. The preferred embodiment provides an audio speaker composite diaphragm. As shown in FIG. 5, it includes the main diaphragm 5 and an auxiliary diaphragm 6. The main diaphragm 5 is made of a MCPET baffle with micropores and the MCPET baffle has the following features: an average size of the micropore is smaller than or equal to 5 m; the micropores are independent from each other; a foaming rate of the MCPET baffle is less than 2 times; a density of the MCPET baffle is less than 300 kg/m.sup.3. The MCPET baffle is further cut in layers to form a membrane 2. At least one surface of the membrane 2 with micropores 201 is exposed to form a micropore exposed surface. A thickness of the membrane 2 is 0.05-1 mm. The membrane 2 is further heated under a temperature of 130-140 C. to form the main diaphragm 5. The auxiliary diaphragm 6 is in shape of a circular or an annular. An external diameter of the auxiliary diaphragm 6 is larger than an external diameter of the main diaphragm 5. The main diaphragm 5 is superposed on the auxiliary diaphragm 6 and is located at the center of the auxiliary diaphragm 6. Specifically, when there is only one micropore exposed surface on the membrane 2, the micropore exposed surface is opposite to a sound transmission direction of the main diaphragm 5. In the preferred embodiment, the main diaphragm 5 is a dome diaphragm, and an annular connected edge 501 is defined on the main diaphragm 5. The main diaphragm 5 is superposed onto the auxiliary diaphragm 6 via the annular connected edge 501. The main diaphragm 5 and the auxiliary diaphragm 6 are pasted or thermal bonded together to form a composite diaphragm. In the preferred embodiment, the auxiliary diaphragm 6 is made of paper pulp or polymer material, and a stiffening ring 7 is fixed on a cylindrical edge of the auxiliary diaphragm 6.

(11) As shown in table 1, the comprehensive performance of an audio speaker made of the dome diaphragm provided by the example two is compared with the comprehensive performance of an audio speaker made of a diaphragm with the same specifications provided by the prior art.

(12) TABLE-US-00001 TABLE 1 PET Diaphragm Diaphragm In The (the average size Present of micropore is Polypropylene Paper Pulp Diaphragm Application larger than 10 m) Diaphragm Diaphragm Thickness 0.05 or above 0.1-0.3 0.1-0.3 0.35-0.40 (mm) Strength high high poor poor Density (kg/m.sup.3) 200-240 1300-1380 1100-1200 700-800 Sound 1950 1800 1750 1600 speed (m/s) Energy Loss 0.04 0.046 0.065 0.035 (tan ) Sensitivity 116 110 108 105 (dB) Sound 112-125 108-118 104-117 98-112 Pressure (dB) Moisture good good good poor Resistance Ageing good good poor poor Resistance Comment low density, high Although obtain Performance Commonly sound speed and high internal loss, similar to the used good weather density is PET diaphragm fastness ensures comparatively diaphragm material, high quality sound high so cannot be but reproduction used for high poor quality sound weather reproduction fastness therefore cannot produce high quality sound

(13) It can be seen from table 1 that although micropores are defined on the diaphragm made of the membrane of the present application, however, in terms of strength, the diaphragm of the present application is still more superior to the diaphragms made of polypropylene and paper pulp. Moreover, the diaphragm of the present application has lower density and a higher strength compared with existing diaphragms. Table 1 shows that the density of the diaphragm of the present application is obviously lower than the density of diaphragms made of other materials. In limit cases, the density of the diaphragm of the present application is only 15% of the density of diaphragms made of PET materials, 18% of the density of diaphragms made of polypropylene, and 28% of the density of diaphragms made of paper pulp in the prior art. That is to say, compared with diaphragms made of other materials, diaphragm of the present application has lighter weight, a lower density and a higher strength, which makes the diaphragm of the present application more suitable for the audio speaker.

(14) In terms of sound speed, the diaphragm of the present application is 8.3% faster than the diaphragm made of PET materials, 11.4% faster than dual diaphragms made of polypropylene, and 21.8% faster than dual diaphragms made of paper pulp. The higher sound transmission speed fully indicates that the diaphragm of the present application has a good performance in improving the inherent diaphragm viscous phenomenon of the diaphragm made of polymer, and thus the sound transmission speed and the sound reproduction ability are improved.

(15) In terms of the energy loss (Tan ), the diaphragm of the present application is 13% lower than the diaphragm made of PET materials, 38% lower than the diaphragm made of polypropylene, and only a little higher than the diaphragm made of paper pulp which has the best performance in terms of the energy loss. A relative small energy loss makes the diaphragm much easier to get back to the original shape thereof after a vibration, and this feature ensures sound distortions and sound clippings are maintained at minimum levels throughout sound reproduction process.

(16) In terms of the sound pressure, within a frequency range of 20 Hz-5500 Hz, the sound pressure produced by the diaphragm of the present application ranges from 101 db to 125 db. The result shows that the diaphragm of the present application can reproduce sound at higher audible levels, which is 3.7% higher than the diaphragm made of PET materials in the prior art, 7.6% higher than the diaphragm made of polypropylene, and 14.2% higher than the diaphragm made of paper pulp. And this indicates that, with the same input power, the diaphragm of the present application is able to reproduce higher sound output, which shows superior sound reproduction efficiency.

(17) In terms of moisture resistance and UV Protection, the diaphragm of the present application is obviously better than the diaphragms made of polypropylene and paper pulp, and this feature represents the durability of the diaphragm of the present application when it is used in a long run