JPS6058640B2 - Method for manufacturing diaphragm for electrodynamic electroacoustic transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electrodynamic electroacoustic transducer in which a diaphragm printed with a conductor circuit is placed in a magnetic air gap, and an audio current is passed through the conductor circuit to vibrate the diaphragm and radiate sound. The present invention relates to a method for manufacturing a diaphragm used for.

A conventional method for manufacturing a diaphragm for an electrodynamic electroacoustic transducer will be described with reference to FIGS. 1A and 2B and FIGS. 2A and 2B.

The diaphragm shown in FIGS. 1A and 1B has a so-called conductor circuit 4 formed by applying an adhesive 2 to an insulator 1 and pasting a conductor foil 3 on it, and then photo-etching the conductor foil 3. It's called laminate. When using this diaphragm as a diaphragm for headphones, the required input resistance is 0.2 to 0.3.
It can be used as the heat resistance is about W and does not require heat resistance.However, when used as a diaphragm for a speaker, even if a polyimide film with excellent heat resistance is used as the insulator 1, the adhesive 2 may be resistant to heat. Even if a relatively heat-resistant polyester adhesive is used as Adhesive 2, the power resistance is only 8W.
I can only get it to a certain extent. It cannot be used because it does not have heat resistance that satisfies the 20W input power required for speakers. In addition, in addition to the insulator 1 and the conductor circuit 4, it is added to the mass of the adhesive 2, so
It has the disadvantage that the sound pressure sensitivity is lowered and the ultra-high frequency characteristics of 20KH2 or more are deteriorated. Further, the diaphragm shown in FIGS. 2A and 2B has a conductive circuit 7 formed by depositing a conductive foil 6 on a heat-resistant insulator 5 and then etching the conductive foil 6.

This diaphragm does not use adhesive, so it is heat resistant.
It can withstand an input of about 28W, so it can be used as a speaker diaphragm, but the tungsten board and aluminum pellets used as vapor deposition materials are expensive, the thickness of the vapor deposited film may be uneven, and the vapor deposition time is long. Therefore, the cost is high and it is not suitable for mass production. The present invention is intended to eliminate the above-mentioned drawbacks, and one embodiment thereof will be described below with reference to the drawings.

In FIGS. 3A and 3B, 8 is a conductive foil, which is made of, for example, aluminum foil with a film thickness of 6 μm. The surface of this conductor foil 8 is coated with ether, pyromellit imide (para, para', diamino), diphenyl (d
A heat-resistant insulator 9 made of polyimide, which is a heat-resistant insulator 9 consisting of ether, pyromellit, amide, imide (rose, rose, diamino, diphenyl) and a hardening agent, is coated with a constant film thickness of about 2 to 6 μm, for example. After heat curing at 150℃, further heat curing at 400℃ for 15 minutes.
After curing by heating for a minute, the conductor circuit 10 is formed by photoetching the conductor foil 8 to have an impedance of, for example, 8Ω, thereby forming the conductor circuit 10 on the film of the heat-resistant insulator 9 without an adhesive layer. You can get a printed diaphragm. The diaphragm 11 is placed parallel to the magnetic flux in the magnetic gap formed by the yoke 12 and the center ball 13 as shown in FIG. It is directly driven and emits sound. Compared to conventional laminated type diaphragms, this diaphragm 11 does not require adhesive, so if polyimide is used as the heat-resistant insulator 9, heat resistance of 400°C can be obtained.
Can withstand 0W of adult power. Furthermore, mass productivity of about 1@ or more can be achieved compared to conventional vapor deposition type diaphragms, and manufacturing costs can be reduced and the thickness of the conductor foil 8 can be made uniform. Furthermore, since it is made into a film by coating, it is possible to obtain a base film (minimum 2μ) that is less than the lower limit film thickness of conventional polyimide film, for example, 25μ, making the diaphragm 11 even lighter, which is one of the characteristics of a speaker that directly drives the diaphragm 11 A certain improvement in ultra-high frequency reproduction and an efficiency improvement of approximately 1.5dB are achieved. Note that a known method for forming a conductor circuit on a heat-resistant insulator is to coat a conductor foil with a heat-resistant insulator made of polyamide resin, and then to form a conductor circuit by etching the conductor foil into a desired shape. However, since polyamide has inferior heat resistance compared to polyimide, the base film must be made approximately 2.7 times thicker in order to withstand input, and the weight subsequently increases, making it difficult to use as a speaker diaphragm. is not appropriate.

As explained above, according to the present invention, a heat-resistant insulator made of liquid polyimide resin is coated on one side of a conductive foil and thermally cured to form a film, and then the conductive foil is etched to pass an audio current. Since it forms a conductor circuit for the purpose, it has high heat resistance and high insulation properties, so it can withstand large amounts of force.It is also easy to manufacture, which reduces manufacturing costs, and it also has higher resistance to power than polyamide. It is possible to manufacture a diaphragm that is lightweight because the base film can be made thinner, and can improve ultra-high frequency reproduction and efficiency.

[Brief explanation of the drawing]

Figure 1A is a perspective view of a conventional diaphragm, and Figure 1B is its I-
1 line sectional view, FIG. 2 A is a perspective view of another conventional diaphragm, FIG. 2 B is a sectional view taken along the line ■-■, and FIGS. 3 A and B are diaphragms manufactured by the manufacturing method of the present invention. An example is shown in Figure 3A.
3 is a perspective view thereof, FIG. 3B is a sectional view taken along the line ■-■, and FIG. 4 is a perspective view showing the main parts of the electrodynamic electroacoustic transducer.

Claims (1)

[Claims] 1. Coat a heat-resistant insulator made of liquid polyimide resin on one side of the conductor foil and heat cure it to form a film.
A method for manufacturing a diaphragm for an electrodynamic electroacoustic transducer, characterized in that the conductor foil is then etched to form a conductor circuit for passing audio current.