JPS5961295A - Acoustic diaphragm and its production - Google Patents

Abstract

PURPOSE:To obtain an acoustic diaphragm with superior characteristics and sensitivity by constituting the diaphragm of a base film and a coating layer including resin to be heardened by radioactive rays and ultraviolet rays and a filler and hardening an scillating surface with radiant rays or the like to harden the oscillating surface to have higher hardness than that of an edge part. CONSTITUTION:The coating layer 2 including the resin to be hardened by the radioactive rays or the ultraviolet rays and a filler is formed on the base film 1. The base film 1 is molded like a prescribed diaphragm shape and rings 3 are adhered to the parts corresponding to the external peripheral edge of the edge part of the acoustic diaphragm. The base film 1 is cut off and separated to many diaphragms and a mask composed of aluminium e.g. is formed on each edge part to prevent the part from being hardened by the radioactive rays or the ultraviolet rays. The radioactive rays or the ultraviolet rays are irradiated to a formed body 10 on which the mask 4 is formed to harden the part corresponding to the oscillating surface up to proper hardness and the mask 4 is remoed. Thus, the acoustic diaphragm with superior the characteristics and sensitivity and fine sound quality is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an acoustic diaphragm for microphones, headphones, speakers, etc., and a method for manufacturing the same.

BACKGROUND TECHNOLOGY AND PROBLEMS In acoustic diaphragms for microphones, headphones, speakers, etc., edges tend to be flexible, while other parts need to be highly rigid. In the resin coating method, which is one of the known manufacturing methods for such an acoustic diaphragm, a thermosetting resin is applied only to the vibration surface of the diaphragm and hardened to increase rigidity. In addition, the applicant has also filed a patent application for
In No. 8804, we proposed a method for manufacturing an acoustic diaphragm that can obtain an acoustic diaphragm with good characteristics and sensitivity, and is suitable for mass production. In this manufacturing method, a small amount of additives (coagulation stopper, sensitizer) are mixed with radiation or ultraviolet curable resin and applied to the entire surface of the base film, which is then molded into the shape of a diaphragm. Only the vibrating surface was irradiated with radiation or ultraviolet light to harden it.

However, in any of these methods, heat, radiation, and ultraviolet curable resins are sticky and fluid in their uncured state, so they tend to stick when the base film coated with the resin is rolled up. Furthermore, there was a problem in that the resin flowed during molding and the coating became uneven. Therefore, another resin was mixed with these 4rtj resins to prevent the buildup, but when this resin to prevent the buildup was mixed, the hardness after curing was reduced, and the coating film was The strength was also reduced. Therefore, the type and amount of resin mixed must be controlled so as to suppress stickiness and fluidity and have the desired strength, which limits the manufacturing conditions and range of applications.

OBJECTS OF THE INVENTION In view of the above problems, it is an object of the present invention to provide an acoustic diaphragm with excellent characteristics and sensitivity, and a manufacturing method suitable for mass production of the acoustic diaphragm.

Summary of the Invention The acoustic diaphragm according to the present invention is composed of a base film, and a coating layer formed on the base film and containing radiation, ultraviolet rays or a thermosetting resin, and a filler. It is characterized in that the surface is hardened by irradiation with radiation or ultraviolet rays or by heating, so that the hardness of the edges is also high. In addition, the method for manufacturing an acoustic diaphragm according to the present invention includes molding a base film having an R71A'5 layer containing radiation, ultraviolet rays, or a thermosetting resin and a filler, and then irradiating the vibrating surface with radiation or ultraviolet rays. It is characterized by being cured by heating or heating.

In the acoustic diaphragm of the present invention, the filler contained in one layer of the coating film is a material that improves the uniformity of the layer by increasing the viscosity of the coating layer and suppressing stickiness and fluidity. , one with even higher rigidity is preferred. Further, it is more preferable to use one filler with a small specific gravity because the coating film is light and the sensitivity of the diaphragm can be increased. Such fullness! As In, microballoons, microscopic silicon carbide, and the like can be used. The microballoon may be made of silicon carbide, carbon, silicon dioxide, alumina, iron oxide, etc., and has an average particle size of 10 to 50μ0.1
It is preferable to use it as late as μ. The above-mentioned filler is used in combination with a resin, and the amount of the filler mixed is preferably 25% by weight or less. This is because if there is too much filler, problems such as a decrease in the strength of the coating film will occur. These fillers can be used alone or in combination depending on the purpose of use.

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

In this invention, any resin that can be used for the case can be used as long as it hardens when irradiated with radiation and/or ultraviolet rays, or is hardened by heat, and can impart the desired 11m1t property to the vibration surface. However, no particular 464
It is not limited to 11N. It is preferable to use monomers or oligomers having a double bond such as acrylic or methane/lyl as such 4-magawa. Among such monomers, those having an acrylic double bond include, for example, vinylpyrrolidone, 2-
Ethylhexyl acrylate, lauryl acrylate,
Monofunctional monomers such as hydroxyethyl acrylate, ethoxyethoxy acrylate, tetrahydrofurfuryl acrylate, Aloex M-5700 (trade name), diethylene glycol diacrylate, tetraethylene glycol diacrylate, pentyl glycol diacrylate, Aloex M-6100 Examples include trifunctional monomers such as (i1 product name), polyfunctional monomers such as trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, 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 with a methacrylic double bond. Moreover, it becomes a skeleton having such a double bond. Examples of the resin 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 above-mentioned resin is preferably used together with a photosensitizer for ω1 use, and upon irradiation with light, the J' and l sensitizers are separated and radicals are generated, which polymerize and crosslink through the radicals. Such j'ρ sensitizers include, for example, benzoin compounds, penzophenone-amiy mixtures, etc.
I get kicked. Examples of +M in the benzoin compound include benzoin alkyl ether, and examples of the alkyl include methyl, isopropyl, n-butyl, and L-butyl.

Examples of amine compounds used in the benzophenone-amine mixture include methyljetanolamine, triethanolamine, N-methylmorpholine, triethylamine, dibutylamine, N,N-dimethylbenzylamine, N,N-dimethylaniline, and the like. Can be mentioned.

This curable resin may contain graphite, polyoxymethylene whiskers, etc. as necessary.
'' can also be added to form a composite.The amount of the reinforcing material can be determined as appropriate, taking into account conditions such as curing speed and pressure moldability.

Next, a method for manufacturing an acoustic diaphragm according to the present invention will be described with reference to the drawings, with reference to the case where a radiation or ultraviolet curable resin is used.

First, as shown in Figure 1, on the base film (1),
A coating layer (2) containing a resin (11) which is cured by radiation, ultraviolet rays, etc. and a redundant material is formed by an appropriate method.

Next, as shown in Figure 2, this base film (1)
is molded into a known predetermined 4h Nb AN shape using a molding machine, and a ring (3) is attached to a portion corresponding to the outer periphery of the edge portion of the acoustic diaphragm. Then, cut and separate the base film into a large number of diaphragms (as shown in Figure 45A), and mask the edges with a suitable material such as aluminum or brass (4). to prevent this part from being hardened by radiation, ultraviolet rays, etc. The molded body + tO) on which the mask has been formed is irradiated with ``C radiation, ultraviolet rays, etc.'' by an appropriate means. Then, the portion corresponding to the vibration surface is hardened to a suitable degree of precipitation, and the mask (4) is removed.

As shown in FIG. 6B, a hardened cloth 1f, 4 (ED) is formed on this molded body ([0).

The fourth item 1 shows an example of a method of irradiating with radiation or ultraviolet rays. In this FIG.
This blurring is followed by a belt conveyor 112) moving at a predetermined speed. These molded bodies (10) are exposed to radiation or ultraviolet light 11 using an irradiation device +13.
Radiation or ultraviolet rays are irradiated onto the craftsmanship that extends below the 1st part.

-1- In the method described above, as the radiation, electrons, γ, glands, etc. are used. In addition, radiation, ultraviolet rays, etc. (the amount of radiation is not particularly limited,
The inner chamber may be selected by taking into account factors such as 1.

Even when a thermosetting resin is used for the radiation pass or the ultraviolet curable resin, the acoustic diaphragm can be manufactured in the same manner as described above. In this case, a heat insulating material is used as the mask, and the resin can be blown once by heating it with a heating device instead of a radiation press or ultraviolet irradiation device. In the manufactured acoustic diaphragm, a cured resin coating layer is formed on the vibrating surface, while 1 and 2 resin remain uncured on the edge portions where the mask is formed. This uncured resin may be removed by a suitable means, such as a solvent, and as shown in FIG. Five layers (5) are formed.The T6 agent for removing the resin in this case is preferably methyl ethyl ketone, methyl isobutyl ketone, Siku, lohexanone, or the like.

In the above-mentioned method for manufacturing the sound #setting board, any of the conventional methods can be used to form the coating I layer on the base film. Examples of i- include a fog method, a brush coating method, a gravure roll method, and a doctor blade method. In addition, the base film with the three bent bars 4 formed in this manner is repeatedly shaped into a well-known predetermined swing d/force plate shape using a molding machine as described above, but this molding method 'V' is not limited to any particular method.
For example, a pressure forming method or the like may be used. Further, these steps can be carried out either continuously or batchwise.

Example polyfunctional acrylate monomer (trade name 1'-DPHAJ
, Nippon Kayakuko M Ll, IO"il) was mixed with 20% finely particulate silicon carbide (trade name "Aerosil", Nippon Aerosil tLtf#) as a filler, and this was further shaped into rods with methyl ethyl ketone. It was coated to a film thickness of 40 μm on a 9 μm thick polyethylene terephthalate film using a doctor blade method. This film was then pressure-molded to form a dome-shaped diaphragm for a dynamic microphone. Next, mask the edge of this diaphragm with aluminum, and the distance is 1'ji & 20.
cm, strong f 80 W/17n, feed speed 10cm
The dome portion was cured by irradiating with ultraviolet rays under the condition of /min.

After curing, this diaphragm was immersed in methyl ethyl ketone to remove the resin at the edges and subjected to MjJA, thereby obtaining a desired diaphragm of an edge-integrated molding type with hardened dome portions.

The results of measuring the output frequency characteristics of a dynamic microphone using this diaphragm are shown by broken lines in FIG. Further, as a comparative example, the output frequency characteristics of a dynamic microphone using a diaphragm not containing a filler, which was measured on an intermediary basis, are shown by a solid line in FIG.

In FIG. 5, in the dynamic microphone of Example 1, the dip in the vicinity of 8I(I(z), which was observed in the comparative example, was eliminated, and the stability in the high range was increased.

Also, the result of the listening test was that the sound "1" came out and the sound became thicker.

Example 2 Polyfunctional acrylate monomer (trade name "J) PHA",
(manufactured by Nippon Kayaku Kogyo ■) was mixed with silicon dioxide microballoons as a filler at a ratio of 10%, and this mixture was applied to a 9μ thick polyethylene terephthalate film to a film thickness of 40μ using a doctor blade method. Next, this film was pressure molded to form a dome-shaped diaphragm of a dynamic microphone. Next, mask the edge of this diaphragm with aluminum and set the distance 1ii.
I 20 cm.

The dome portion was cured by irradiating ultraviolet rays at an intensity of 80 W/cm and a feed rate of 10 Cm/min. After curing, this diaphragm was immersed in methyl ethyl ketone to remove the resin at the edges, and then dried to obtain a desired diaphragm with a hardened edge molding mold.

The results of measuring the output frequency characteristics of a dynamic microphone using this diaphragm are shown in foreshadowing in FIG. In addition, the output frequency l characteristic of the dynamic microphone using the diaphragm of the comparative example described above is
Shown in the figure as a solid line.

In Figure 6, the dynamic microphone of Example 2 had higher overall sensitivity and increased mounting stability compared to the comparative example. Also, the listening results showed that the volume was not loud.
As in Example 1, the sound rl] was obtained and the thickness was 1st place.

Example 6 In Example 1, except that the mixed amount of Aerosil was 5%/ll! i l'/IJ A dome-shaped diaphragm of a dynamic microphone was formed in the same manner as in 1.

In this case, the coating thickness when the coating layer was formed on the base film was 49μ±6μ. During molding, the coating thickness was 49μ±4μ, with almost no change in the uniformity of the coating thickness. In contrast, a strong diaphragm containing Aerosil formed as a comparative example had a film thickness of 49 μm during molding.
It came out with a variation of ±15μ, making it non-uniform.

Further, the molded diaphragm was irradiated with ultraviolet rays in the same manner as in Example 1 to remove the wood grains on the edge portions and obtain a desired diaphragm with a hardened dome portion. The output frequency N'Ff characteristic measured by incorporating the obtained diaphragm into a microphone unit is shown by a broken line in FIG. Also, the ratio 1
The output frequency of a microphone using a diaphragm of 1i & 1+1J is shown by a solid line in Figure ff37. The data shown in FIG. 7 was obtained using a different unit from those shown in FIGS. 5 and 6.

As shown in Figure 7, in the comparative example, there is a large dip in the surface area due to the unstable movement of the reaction plate, but in Example 6, the dip in the high range is small and the shoulder characteristics in the low range are also low. In addition, the directional characteristics of Example 6 were also better than those of Example 1, and the listening results showed that the sound was clear and lively.

In addition, the Nj'f physical properties of the diaphragms obtained in Example 6 and Comparative Examples are shown below. (2, il!) are used to show the physical properties of a diaphragm that does not contain a filler, and Reference Example 2 shows the physical properties of a diaphragm that uses only a base film of polyethylene terephthalate.

(The following is a margin, continued in the next I.) As shown in the table, it can be seen that the diamond slam of Example 6 has the highest sound speed and the lowest Q value, and is an ideal diamond slam.

Effect of development +314 The present inventor achieved adhesiveness and fluidity by first mixing a resin that has adhesiveness and fluidity but is hard when cured, and a resin that is not adhesive and fluid but is soft. We came up with the idea of forming a coating layer that is hard enough to reduce the amount of hardness, and experimented with making a prototype of this, but there was a limit to the hardness of this coating layer.

However, with the acoustic vibration H'rH,l plate of the present invention, the stickiness and fluidity can be suppressed without mixing almost any of the above-mentioned soft resin, so that a harder coating layer can be obtained. became. Therefore, when winding up the film coated with 48711 in the manufacturing process, the film does not stick, making the work easier and making it possible to further increase the silicicity.

Furthermore, even when the molding temperature was raised when molding the film into the shape of a diaphragm, the applied resin did not flow and become non-uniform, and a uniform coating layer was obtained. As a result, the acoustic diaphragm moves smoothly when used in microphones and speakers.

In view of the above, the present invention has made it possible to provide an acoustic diaphragm with excellent sensitivity and various physical properties and good sound quality, and a manufacturing method that allows mass production of such an acoustic diaphragm.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the structure of the material of the acoustic diaphragm used in this invention, Fig. 2 is a sectional view showing the molded state, and Fig. 6 is a sectional view showing the structure of the material of the acoustic diaphragm used in this invention.
Figure A is a top view showing the state with the mask on, Figure 5B is a view showing the state where the resin is hardened. A cross-sectional view showing,
FIG. 4 is a perspective view showing the irradiation state of radiation or ultraviolet rays;
Figures 5, 6, and 7 show the output frequency &Q of a dynamic microphone using an acoustic diaphragm according to the present invention.
It is a curve diagram showing % property. In addition, in the symbols used in the drawings, (11...
・・・・・・Base film (2)・・・・・・・・・・・・
... Coating layer (4) ... Mountain mask (5) - Hardened coating layer (10) - Molded body 131 ... Irradiation unit. Agent: Toshiki Sugiura - Kazuichi Katsuto Kazuo Ueya

Claims (1)

[Scope of Claims] 1. A paste film, which is composed of a base film and a coating layer containing a radiation-curable, ultraviolet-curable or thermosetting resin and a filler, and whose vibration 1. An acoustic diaphragm jjJ) board, characterized in that the surface is hardened by irradiation with radiation or ultraviolet rays or by heating, so that the hardness is higher than that of the edge portions. 2. After forming a base film with a coating layer containing a radiation-curable, ultraviolet-curable or thermosetting resin and a filler into the shape of a moving plate, the vibrating surface is irradiated with radiation or ultraviolet rays. % to heat and harden
A method for manufacturing an acoustic diaphragm.