JPS5934797A - Manufacture of sound diaphragm - Google Patents

Abstract

PURPOSE:To obtain a sound diaphragm where sound sensitivity is not deteriorated even at a high frequency with a simple means, by irradiating untraviolet rays or the like on a coating layer of an ultraviolet ray curing resin so as to cure it partially and eliminating the part not cured. CONSTITUTION:The resin 2 cured with radiant rays or ultraviolet rays is formed on a base film 1 with a suitable method, the base film 1 is formed into a prescribed diaphragm shape by using a forming machine and a ring 3 is adhered to a part corresponding to an outer circumference of the edge of the sound diaphragm. Then, the base film 1 is cut off into lots of diaphragms and after a mask 4 is formed at the edge with a suitable material, the diaphragm plane is cured into a suitable hardness by irradiating radiant rays or untraviolet rays and the mask 4 is removed. Thus, the resin layer 2 remains uncured on the edge where the mask 4 is formed, and a resin layer 5 is formed to a forming part 10, where only a part corresponding to the diaphragm is cured, by removing the uncured part.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing an acoustic diaphragm for microphones, headphones, speakers, etc. BACKGROUND TECHNOLOGY AND PROBLEMS Acoustic vibrations for microphones, headphones, speakers, etc. It is necessary for the board to have flexibility at the edges and high rigidity at other parts.There are various known methods used to form such an acoustic imaging board. All of them have the disadvantage that they are not suitable for mass production and the characteristics of the products are not constant.

In the lamination method, which is one of such known methods,
Another film, such as a polyethylene terephthalate film, is laminated only on the vibration surface of the diaphragm.

This method requires the preparation of another film coated with adhesive, and still requires a complicated process of cutting the film to a specified size and stretching it to a specified location, making it unsuitable as a mass production method. do not have. In the resin coating method, which is another known method, resin is applied only to the vibration surface of the diaphragm and cured to increase rigidity. It is difficult to partially apply the resin to -1,f: only on the vibrating surface, and uneven coating is likely to occur, which may cause variations in the characteristics of the product. Furthermore, in the single-layer molding method, which is another known method, the diaphragm is molded in a single layer so that the vibrating surface of the diaphragm is thick and the edge portions are thin. However, with this method, the thickness between the vibrating surface and the edge part is extremely precise.

It is difficult to mass-produce products with uniform characteristics.

In order to eliminate such drawbacks, the present inventor proposed in Japanese Patent Application No. 198803/1987 a structure composed of a base film and a resin layer made of a radiation or ultraviolet curable resin, the vibration surface of which is not exposed to radiation or ultraviolet rays. We have proposed an acoustic diaphragm that has increased rigidity by being hardened by ultraviolet irradiation, and a method for manufacturing the same. However, in this case, the resin layer is left uncured at the edge portions, but a new phenomenon occurs in that the acoustic sensitivity decreases as the coating thickness increases in the high frequency region. A problem arises.

Purpose of the Invention In view of the above points, the present invention provides a method for manufacturing an acoustic diaphragm that is suitable for mass production, has constant product characteristics, and has good sensitivity even in the high frequency range of the obtained acoustic diaphragm. It is something to do.

Summary of the Invention The present invention involves forming a base film on which a coating layer of a radiation or ultraviolet curable resin is formed into a diaphragm shape, and then irradiating the vibrating surface of the diaphragm shaped molded body with radiation or ultraviolet rays to achieve the above-mentioned properties. An acoustic vibration device characterized in that the coating layer is partially cured, and then the uncured portion of the coating layer is removed. The present invention relates to a method for manufacturing an 11II plate.

EXAMPLE A method of manufacturing an acoustic diaphragm according to the present invention will be explained with reference to the drawings.

First, as shown in Figure 1, on the base film (1),
A resin (2) that is cured by radiation or ultraviolet light is formed by an appropriate method. Next, as shown in Figure 2, this base film (3) is molded into a well-known predetermined diaphragm shape using a molding machine, and a ring (3 ). Next, as shown in FIG. 6A, the base film is cut into a number of diaphragms #l, and a mask (4) is formed on the edge portions using a suitable material, and these portions are irradiated with radiation, ultraviolet rays, etc. to prevent hardening. The molded body (10) in which the mask has been formed is irradiated with radiation, ultraviolet rays, etc. by an appropriate means to harden its vibrating surface to an appropriate hardness, and then the mask (4) is heated.
). As a result, the molded body 0()) contains the 5th B
As shown in the figure, while a hardened resin layer (5) is formed, the resin layer (2) is formed on the edge portion where the mask is formed.
is left uncured. When this resin 7@(2) is removed by an appropriate means, for example, with a solvent, as shown in FIG. A layer (5) is formed to provide stiffness.

FIG. 4 shows an example of a method of irradiating with radiation or ultraviolet rays. In FIG. 4, a large number of molded bodies 00) forming masks are arranged on a plate (1υ), and these plates (1υ) are placed on a belt conveyor (1) rotating at a predetermined speed. The molded body (10) is irradiated with radiation or ultraviolet rays when passing under the radiation or ultraviolet ray irradiation device (I3). Another method for producing an acoustic diaphragm is as shown in FIG. First, as described above, only the base film (1) is molded into a well-known predetermined diaphragm shape, and then resin is sprayed (1).
A diaphragm can be manufactured by spraying from scratch to form a resin layer (2) and then using the same method as described above.

In this invention, the material that can be used as the base film is not particularly limited as long as it has been conventionally used in acoustic diaphragms, but polyethylene terephthalate is particularly preferred.

The method for applying resin onto this base film is as follows:
Any conventional method can be used, and examples include a spray method, a brush coating method, a gravure roll method, and a doctor blade method.

As mentioned above, the base film coated with resin is molded into a well-known predetermined shape using a molding machine, but the molding method applied in this case is not limited to any particular method. For example, a suitable molding method such as a pressure molding method may be used. Moreover, the molding into a predetermined shape can be carried out by either a continuous method or a batch method.

Further, as described above, even when the base film is molded before forming the resin layer, the molding can be performed in the same manner as the above-mentioned method. 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, Aroex M-5700 (commercial product) monofunctional monomers such as diethylene glycol diacrylate, tetraethylene glycol diacrylate, neopentyl glycol diacrylate, difunctional monomers such as Aroex M-6100 (product name), trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate , dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and other polyfunctional monomers.

Examples of such monomers having a methacrylic double bond include those in which the acrylic double bond of the above-mentioned monomer is replaced with a methacrylic double bond. Further, examples of the resin layer having the double bond and serving as the skeleton include alkyd resin, polyester, acrylic resin, polyurethane, and epoxy resin. When an oligomer is used as the resin, it may be converted into an oligomer using a conventional method using the monomers described above.

The resin as described above is preferably used together with a photosensitizer, and upon irradiation with light, the sensitizer decomposes to generate radicals, which polymerize and crosslink through the radicals. Examples of such sensitizers 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 the amine compound used in the benzophenone-amine mixture include methyljetanolamine, triethanolamine, N-methylmorpholine, triethylamine, diptylamine, N,N-dimethylbenzylamine, N,N-dimethylaniline, and the like. It will be done.

As described above, the uncured portion of the resin layer (2) is removed, for example, by using a solvent, and examples of the solvent include methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

The molded product obtained as described above is cut and separated into a large number of molded product pieces constituting each diaphragm, or in a continuous state without being cut and separated, predetermined portions, that is, edge portions, are coated with aluminum, It is masked with brass or the like, and then exposed to radiation or ultraviolet rays to harden the exposed resin parts and give them a certain level of rigidity. As the radiation, electron beams, gamma rays, etc. are used. 'Also, the amount of radiation, ultraviolet rays, etc. is not particularly limited;
It may be selected as appropriate, taking into consideration the type of resin, curing speed, etc.

The present invention will be explained below using specific examples.

A polyethylene terephthalate film with a thickness of 9 μm was used as a base film, and a polyfunctional acrylate monomer (i?5 product name rDPHA-J,
A laminated film was prepared by applying a mixture of Nippon Kayaku Kogyo Co., Ltd.) and a filler to prevent flow to a film thickness of 40 μm using a doctor blade method.

Next, this laminated film was pressure molded to form a dome-shaped diaphragm for a dynamic microphone. Mask the edge of this diaphragm with aluminum,
Distance 20ctn, strong [80W/''% feed speed 10tn
The dome portion was cured by irradiating ultraviolet rays at a rate of 1/min. Next, this diaphragm was immersed in methyl ethyl ketone to remove the resin at the edges and dried to obtain a desired diaphragm.

The results of measuring the output frequency characteristics of a dynamic microphone using this diaphragm are shown by broken lines in Figure 6.

As a comparative example, FIG. 6 shows the output frequency characteristics of a dynamic microphone using a diaphragm made only of 9μ polyethylenetetra W crate film, which was similarly fixed at i1+11.

In FIG. 6, the microphone using the diaphragm according to the present invention has a 5.000 to 20
The high range up to ,000H7 rises, the ordinary part extends to the high range, and the range from 500 to 10, OOOiIz
The sensitivity of the area is also not as good as Tsumugi. The listening results showed that the high range was extended, the low range was well-defined, and the mid-range was well-defined, and the sound localization was good overall.

Specific Example 2 A polyethylene terephthalate film with a thickness of 12 μm was used as a base film, and polyfunctional acrylate motsuma (trade name “Aronix”) was applied on this base film.
A mixture of Toagosei Kagaku Kogyo (I'll JQ) and a filler to prevent flow was applied to a film thickness of 50 μm using a doctor blade method to prepare a laminated film.

Next, using this laminated film, we made a tweeter dome II diaphragm for a two-way speaker system.
The dome portion and edge portion constituting the vibrating surface were integrally formed by pressure molding. Mask the edge of this diaphragm with aluminum, and
The diaphragm was irradiated with ultraviolet rays to cure the dome 1τ1 under conditions of W/Cm and feed rate of 106″rnZ.Next, this diaphragm was immersed in methyl ethyl ketone to remove the resin at the edges and dried to form the desired diaphragm. The result of measuring the sound pressure frequency characteristics of a two-way speaker system using this diaphragm is shown by the broken line in FIG.

Further, as a comparative example, the sound pressure frequency characteristics measured in the same manner for a two-way speaker system using a diaphragm made only of a 12 μm thick polyethylene terephthalate film are shown by solid lines in FIG.

Also in FIG. 7, in the two-way speaker system using the diaphragm according to the present invention, the high range is extended compared to the comparative example, and this is particularly noticeable around 20.0OOH7. Also, the listening results showed that the stability in the high range was increased and the extension was good.

Effects of the Invention The advantages achieved by the present invention are as follows. Firstly, in conventional double molded films, when molding the base film, another film coated with adhesive is positioned and stretched together, which requires a time-consuming and complicated process. However, the present invention does not require this, and has the great advantage of being able to be mass-produced efficiently on a production line.Secondly, by controlling the amount of radiation (or ultraviolet rays) irradiation, the modification of the vibration surface can be easily controlled. can.

Thirdly, in order to remove the uncured portion of the resin coating layer, the acoustic diaphragm as a whole can be reduced to 11 (1), effectively preventing a decrease in its sensitivity, especially when the resin coating layer is thick. Therefore, it is possible to provide speakers, headphones, microphones, etc. with particularly good high-frequency characteristics.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of the sound η°18 diaphragm used in the present invention, FIG. 2 is a cross-sectional view showing the molded state, and FIG. 3A is a cross-sectional view showing the masked state. Fig. 6B is a cross-sectional view showing the state in which the resin has hardened, Fig. 6C is a cross-sectional view showing the state after removing the uncured portion of the resin, and Fig. 4
The figure shows radiation iMj! 5 is a cross-sectional view showing the state in which a resin layer is formed by the blowing method; FIG. 6 is a perspective view showing the state of irradiation with ultraviolet rays; FIG. Curve diagram shown, @
FIG. 97 is a curve diagram showing the sound pressure frequency characteristics of a two-way speaker system for explaining the present invention. In addition, in the symbols used in the drawings, (1)
Base film (2) Resin layer (4) ・ Mask (5) ・ ・ Cured resin layer (ft11 Molded object (1,1 irradiation device) Agent Ueya Katsutsuneko Yoshio Sugiura Toshiya Figure 1 Figure 2 figure

Claims (1)

[Claims] After forming a base film on which a coating layer of radiation or ultraviolet curing resin is formed into the shape of a diaphragm, the vibration surface of the diaphragm-shaped molded body is irradiated with radiation or ultraviolet rays to cure the vibration surface portion of the coating layer. A method for manufacturing an acoustic diaphragm, characterized in that a cured portion and a non-hardened portion are formed in the coating layer by curing, and then seven portions of the non-cured portion of the coating layer are removed.