JPS6282900A - Dome type diaphragm for speaker - Google Patents

Abstract

PURPOSE:To improve the reproducing capacity of a high frequency band and to obtain superior appearance diaphragm by molding a composite film forming a top coat obtained by kneading graphite powder into a prescribed bonding agent on one side of a base film like dome. CONSTITUTION:The surface of the polyester base film 1 with 75-100mu thickness is coated with a top coat layer 2 obtained by kneading 15wt% scaly graphite into a two liquid polyurethan bonding agent or a double fluid epoxy bonding agent with 5mu thickness. The composite film is molded like a prescribed dome on the basis of compression molding method to form a diaphragm for a speaker. The rigidity of the diaphragm is increased by the coating layer formed on the surface of the diaphragm, extending effect of a high frequency limit frequency is obtained and harmonic distortion can be also reduced. In addition, the superior appearance speaker diaphragm having a metallic gloss can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a speaker diaphragm used in various types of audio equipment.

Conventional technology Conventionally, the diaphragm for semi-hard dome speakers is made of polyester film or a polyester film treated with aluminum vapor deposition, which is formed into a dome shape by pressure forming or heat forming. Ta.

Problems to be Solved by the Invention Such a dome-shaped speaker diaphragm has low rigidity, so it is unsatisfactory in terms of physical properties as a tweeter diaphragm aimed at reproducing high frequency bands, and the polyester film itself is translucent. It is a beautiful color.

A silver-colored appearance can be obtained by applying aluminum vapor deposition to the surface, but the practical range is limited. There was a problem in that it could not be used as a Hi-Fi dome speaker, where appearance is important.

The present invention aims to eliminate the above-mentioned drawbacks and provides a semi-hard dome-shaped speaker diaphragm made of a polyester film and having a black appearance and high reproduction ability in a high frequency band.

Means for Solving the Problems In order to solve the above problems, the present invention incorporates graphite into a two-component polyurethane adhesive or a two-component epoxy adhesive on one side of a polyester film serving as a base film. It is constructed by molding a composite film with a top coat layer into a predetermined dome shape using a pressure forming method.

Effect This configuration increases the rigidity of the diaphragm, extends the high limit frequency, enables reproduction of high frequency bands, and reduces harmonic distortion.The color of the diaphragm is made of graphite. By mixing it, a gold 4 lustrous appearance can be obtained.

Embodiment An embodiment of the present invention will be explained with reference to FIGS. 1 and 2. FIG. 1 shows a sectional view of a diaphragm for a dome-shaped speaker according to the present invention. In Fig. 1, 1 is a polyester base film, 2 is the surface (one side) of the polyester base film 1, K is a top coat made by kneading 15% wt% of flaky graphite into a two-component polyurethane adhesive or two-component epoxy thread adhesive. The layer has a thickness of 5μ. The thickness of polyester base film 1 is 75
~100μ is practical. Such a composite film is formed into a predetermined dome shape by compression molding to form a speaker diaphragm.

In order to compare the vibration of a dome-shaped speaker with such a structure with that of a conventional polyester film alone (76μ) without forming a coating layer, a diameter of 26mm was used.
Figure 2 shows the results of frequency analysis performed with the voice coil installed. In FIG. 2, the broken line represents the frequency characteristics of a diaphragm without surface treatment as in the past, and the solid line represents the frequency characteristics of a diaphragm with no surface treatment applied to the diaphragm according to the present invention. 7 shows the frequency characteristics of a diaphragm formed by kneading graphite and forming a coating layer. As is clear from a comparison of both curves, the coating layer formed on the surface of the diaphragm increases the rigidity of the diaphragm, has the effect of extending the upper limit frequency, and at the same time has the effect of reducing harmonic distortion.

As described in detail, according to the present invention, the frequency characteristics of the dome-shaped speaker diaphragm, in which the above-mentioned coach ink layer is formed on one side of a polyester base film, extend the upper limit frequency and reduce harmonic distortion. It is possible to obtain a diaphragm for a dome-shaped speaker that not only has sufficient performance as a tweeter responsible for reproducing high frequency bands, but also has a metallic luster and is excellent in appearance.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a dome-shaped speaker diaphragm according to the present invention, and FIG. 2 is a frequency characteristic diagram of the conventional speaker diaphragm and the present invention speaker diaphragm. 1...Polyester paste film/L/mu, 2.
...Top coat layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Fig. 2) FI Nabuki

Claims (1)

[Claims] A dome shape characterized by forming a composite film into a dome shape with a top coat layer formed by kneading graphite powder into a two-component polyurethane adhesive and a two-component epoxy adhesive on one side of a polyester base film. Diaphragm for speakers.