JPH0254720B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acoustic diaphragm and a method for manufacturing the same, and more particularly, it relates to an acoustic diaphragm with an integrally molded edge portion and a method for mass producing such an acoustic diaphragm. be.

Acoustic diaphragms for microphones, headsets, speakers, etc. need to have flexibility at the edges and high rigidity at other parts. Various methods have been used to mold such acoustic diaphragms, but all of them have drawbacks such as being unsuitable for mass production and having inconsistent product characteristics. In the lamination method, which is one of the known methods, another film, such as a polyethylene terephthalate film, is laminated onto the vibrating surface. This method requires the preparation of a separate film coated with adhesive, and requires a complicated process of cutting the film to a predetermined size and pasting it together, making it unsuitable for mass production. In the resin coating method, which is another known method, resin is applied to the vibrating surface and hardened to increase rigidity, but since the coating is done by brushing, dripping, spraying, etc., uneven coating tends to occur. , there is a risk that the characteristics of the product may vary. Furthermore, in the single-layer molding method, which is another known method, the vibrating surface is made thicker and the edge portions are thinner, thereby performing single-layer molding. However, in this method, the thickness of the vibrating surface and the edge portion must be determined extremely precisely, and the manufacturing method seems to be difficult.

Accordingly, the present invention has been made particularly to improve the drawbacks of the known methods as described above, and relates to an acoustic diaphragm having an improved structure and a method for manufacturing the same.

The acoustic diaphragm according to the present invention has a laminate including a base film and a resin layer provided on the base film and made of a radiation or ultraviolet curable resin, so that the vibration surface and the edge portion are mutually connected to each other. The vibrating surface is integrally formed, and the resin layer on the vibrating surface is hardened by irradiation with radiation or ultraviolet rays, so that the hardness of the vibrating surface is greater than the hardness of the edge portion.

Further, the method for manufacturing an acoustic diaphragm according to the present invention includes coating a base film with a radiation or ultraviolet curable resin almost uniformly to form a laminate composed of the base film and a resin layer, and then The laminate is molded into approximately the shape of an acoustic diaphragm consisting of a vibrating surface and an edge portion, and then radiation or ultraviolet rays are irradiated to the molded product with the edge portions of the molded product being masked to make the molded product. The vibrating surface is characterized in that the hardness of the vibrating surface is made greater than the hardness of the edge portion by hardening the resin layer on the vibrating surface.

A method for manufacturing an acoustic diaphragm according to the present invention will be explained with reference to the drawings. As shown in FIG. 1, a resin layer 2 that is cured by radiation or ultraviolet rays is formed on a base film 1 by an appropriate method to form a laminate composed of the base film 1 and the resin layer 2. Next, as shown in FIG. 2, this laminate is molded into a predetermined shape using a molding machine, and a ring 3 is adhered to a portion corresponding to the outer periphery of the acoustic diaphragm.
Subsequently, as shown in FIG. 3, the laminate is cut into individual diaphragms, a mask 4 is formed on the edge portions using a suitable material, and irradiation such as radiation or ultraviolet rays is irradiated. Try to prevent it from hardening.

The molded body with the mask formed thereon is irradiated with radiation, ultraviolet rays, etc. by an appropriate means to harden the vibrating surface to an appropriate hardness. For example, as shown in FIG. 4, a plate 12 on which molded bodies 11 each having a mask formed thereon is placed on a belt conveyor 10 rotating at a predetermined speed.
The resin is cured by passing it through an ultraviolet transmission device 13.

In another method for producing a diaphragm, as shown in FIG. Then, a diaphragm can be manufactured in the same manner as described above.

In this invention, the material that can be used as the base film is not limited in any way as long as it is used in acoustic diaphragms, and polyethylene terephthalate is particularly preferred.

Any conventional method can be used to apply the resin onto this base film.
Examples include a spray method, a brush coating method, a gravure roll method, and a doctor blade method.

The base film coated with resin in this manner is then molded into a desired shape using a molding machine. The method applied in this case is not limited to any particular method, and an appropriate molding method such as a pressure molding method may be used. Also,
Molding into a predetermined shape can be carried out either by a continuous method or by a batch method.

Furthermore, when molding the base film before forming the resin layer, the base film can be molded in the same manner as described above. In this case, the resin may be applied to a base film formed into a predetermined shape by, for example, a spraying method.

The resin that can be used in this invention may be any resin that can be cured when irradiated with radiation and/or ultraviolet rays and impart desired rigidity to the vibrating surface, and is not limited to any specific resin. It's not a thing. As such a resin, it is preferable to use, for example, a monomer or oligomer having an acrylic or methacrylic double bond. Among such monomers, those having an acrylate double bond include, for example, vinylpyrrolidone, 2-ethylhexyl acrylate, lauryl acrylate, hydroxyethyl acrylate, ethoxyethoxy acrylate, tetrahydrofurfuryl acrylate, Aronix M-
Monofunctional monomers such as 5700 (trade name), diethylene glycol diacrylate, tetraethylene glycol diacrylate, neopentyl glycol diacrylate, bifunctional monomers such as Aronix M-6100 (trade name), trimethylolpropane triacrylate, tetramethylolmethane Examples include polyfunctional monomers such as tetraacrylate, dipentaerythritol hexaacrylate, and dipentaerythritol pentaacrylate. Examples of such monomers having a methacrylic double bond include those in which the acrylic double bond of the above-mentioned monomer is replaced by a methacrylic double bond. Furthermore, examples of the resin species that form the skeleton having such double bonds include alkyd resins, polyesters, acrylic resins, polyurethanes, and epoxy resins. When an oligomer is used as the resin, it may be converted into an oligomer using a conventional method using the monomers described above.

It is preferable to use the above-mentioned resin together with a photosensitizer, and upon irradiation with light, the sensitizer decomposes to generate radicals, which polymerize and crosslink through the radicals. Such sensitizers include, for example,
Examples include benzoin compounds and benzophenone-amine mixtures. Examples of benzoin compounds include benzoin alkyl ethers, and examples of the alkyl group include methyl, isopropyl, n-butyl, and t-butyl.
Examples of amine compounds used in the benzophenone-amine mixture include methyldiethanolamine, triethalamine, N-methylmorpholine, triethylamine, dibutylamine,
Examples include N,N-dimethylbenzylamine and N,N-dimethylaniline.

The molded product obtained as described above may be cut into individual molded products constituting the diaphragm, or the predetermined portions, that is, the edges, may be masked with aluminum, steel, etc. Then, the exposed resin portion is cured by irradiation with radiation, ultraviolet rays, etc. to give it a predetermined rigidity. As the radiation, electron beams, gamma rays, etc. are used.
Furthermore, the amount of radiation, ultraviolet rays, etc. to be irradiated is not particularly limited, and may be appropriately selected in consideration of the type of resin, curing speed, etc.

This invention will be explained below with reference to Examples.

Example 1 A mixture of a polyfunctional acrylate monomer (product name "DPHA", manufactured by Nippon Kayaku Co., Ltd.) and microballoons was added to a 12 micron thick polyethylene terephthalate film to a thickness of 25 microns using the doctor blade method. I applied it to make it look like this. Using this material, a cone-shaped speaker diaphragm is formed by air pressure, and then the edges are masked with aluminum and the distance is
It was cured under the conditions of 20 cm, ultraviolet light intensity of 80 W/cm, and feeding intensity of 5 cm/min.

When we measured the properties of the obtained diaphragm, we found that Q=
It was low at 20-30, fast at c=√=3000m/sec, and the resolution and sharpness of the sound were good.

Example 2 A mixture of acrylate monomer (trade name "Aronix", manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and graphite was added to a 12 micron thick polyethylene terephthalate film to a thickness of 25 micron using a doctor blade method. I applied it to make it look like this. This was pressure-formed in the same manner as in Example 1, the edges were masked, and then irradiated with an electron beam of 5.0 Mrad at a feed rate of 50 cm/sec to cure it.

When we investigated the performance of this cone-shaped speaker diaphragm, we found that Q=80, but c=√
Extremely high rigidity with ρ = 4000 to 5000m/sec,
The high-frequency sound quality has improved.

The advantages achieved by this invention are as follows. Firstly, in conventional double molded films, they were cut after resin coating, and then positioned and pasted together when forming the base film, which required a time-consuming and complicated process. It has the great advantage that it is not needed in the invention and can be efficiently mass-produced on a line. Secondly, both the conventional single-layered film and double-layered film have thicker and heavier vibration surfaces, so they have the disadvantage of poor sound quality, especially in the high range.
In this invention, the thickness of the vibrating surface is the same as the thickness of the edge part, and the strength is increased simply by changing the hardness of the surface, so it is possible to practically increase E/ρ and improve the high-frequency sound quality. be able to. Thirdly, depending on the type of resin constituting the resin layer, it is possible to give the edge part a damping effect, but in the conventional method, the edge part is not controlled. Fourthly, by controlling the output of irradiation beams such as electron beams, it is possible to easily control the modification of the edge portion or the vibrating surface, and depending on the material of the mask, the edge portion can also be controlled.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the structure of the material used in this invention, Fig. 2 is a cross-sectional view showing the molded state, Fig. 3 is a cross-sectional view showing the masked state, and Fig. 4 is the irradiated state. FIG. 5 is a sectional view showing a state in which a resin layer is formed by a spraying method. In addition, in the symbols used in the drawings, 1...
... base film, 2 ... resin layer, 4 ... mask, 11 ... molded body, 13 ... (ultraviolet) transmission device.

Claims (1)

[Claims] 1. The vibration surface and the edge portion are integrally formed with each other by a laminate composed of a base film and a resin layer formed on the base film and made of a radiation- or ultraviolet-curable resin. , wherein the resin layer on the vibrating surface is cured by irradiation with radiation or ultraviolet rays, so that the hardness of the vibrating surface is greater than the hardness of the edge portion. 2. A radiation or ultraviolet curable resin is almost uniformly applied onto the base film to form a laminate consisting of the base film and the resin layer, and the laminate is then applied to an acoustic layer consisting of a vibrating surface and an edge portion. The resin layer on the vibrating surface of the molded product is cured by molding it into approximately the shape of a diaphragm, and then irradiating the molded product with radiation or ultraviolet rays while masking the edge portions of the molded product. Accordingly, there is provided a method for producing an acoustic diaphragm, characterized in that the hardness of the vibrating surface is greater than the hardness of the edge portion.