JPS58114698A - Diaphragm for flat plate speaker - Google Patents

Abstract

PURPOSE:To prevent a reduction of the resonance frequency at a high frequency band of a diaphragm due to a change of temperature, a rise of temperature when the diaphragm is used, etc., by securing the linkage via an air path between the open air and a cell having a number of rugged parts formed to a core plate of the diaphragm. CONSTITUTION:A core material 1 has a number of cells, and this cell contains honeycomb-shaped rugged parts which are formed by softening a polyacrylate resin film of 200mum thick after heated up to about 350 deg.C and then forming it by a vacuum air-pressure forming process with a 19cm diameter and 6mm. height. The black and white cells 3 and 4 from rugged parts to each other, and the cells 3 and 4 link the open air via air paths 5 and 6. A surface plate 2 made of an aluminum foil of 20mum thick is adhered with heat to both sides of the core plate 1 by means of a hot-melt adhesive. In such a way, the cells 3 and 4 link the open air through the paths 5 and 6 and at the periphery of a diaphragm. As a result, the atmospheric pressure within the cell has no change even with the rise of temperature, etc. This prevent a reduction of the resonance frequency at a high frequency band.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diaphragm for a flat speaker,
The purpose is to provide a diaphragm for a flat speaker that is easy to manufacture and has high rigidity.

Cone diaphragms made of paper pulp and molded are generally widely used as conventional speaker diaphragms.However, cone diaphragms have a flat 11mm diaphragm because the inner and outer peripheries are misaligned with respect to the sound source.・There is a drawback that the pressure frequency characteristics cannot be changed. A flat speaker with a flat diaphragm and aligned sound sources has been developed as a flat speaker with sound pressure frequency characteristics, and can be effectively used in equipment such as televisions and radios where mounting has a limited surface area. ing.

This flat diaphragm has low rigidity against bending when used as a diaphragm alone, so split vibrations are likely to occur, and it is difficult to maintain a flat sound pressure characteristic over a wide band. In order to solve this problem, a flat plate diaphragm was developed that has a core made of plastic foam such as styrofoam and a surface plate made of Al ζ foil attached to both sides, but this flat plate diaphragm is easy to manufacture. It has the advantage that it can be provided at a low cost, but on the other hand, it has the disadvantages of being heavy and having poor efficiency. In order to improve this point, the core root was formed into a honeycomb shape or a lattice shape using a thermoplastic synthetic tree 110 film, as shown in 1-. In the figure, 1 is a core formed in a honeycomb shape using a thermoplastic synthetic resin film, and 2 is a surface plate made of metal foil or plastic film.

By the way, when the surface plate 2 is attached to both sides of the stone plate 1, the stone plate 1 forms an aggregate of sealed honeycomb cells.
Due to temperature changes, the air pressure within the honeycomb cells fluctuates, causing unevenness on the surface plate 2. In addition, the hot bonding between the stone plate 1 and the surface plate 2 is performed at a temperature of 100 to 200 degrees Celsius, but the air inside the honeycomb cells expands during heat bonding and is lost to the outside, so when the temperature returns to room temperature, the honeycomb cells There is no vacuum inside the cell, which also causes unevenness on the top plate. When unevenness occurs on the surface of the diaphragm, the bending rigidity decreases, and the resonant frequency in the high frequency band decreases. The present invention is intended to solve this problem.

The diaphragm for a flat speaker according to the present invention has a stone plate in which a large number of cells are formed in a honeycomb shape or a lattice shape using a thermoplastic synthetic resin film, and surface plates made of light metal foil or hub plastic film are provided on both sides of the stone plate. In the attached flat plate diaphragm, each of the plurality of cells has an air passage that communicates with each other, and has a structure in which peripheral end surfaces of the flat plate diaphragm communicate with the outside air. An embodiment thereof will be described below with reference to FIG. 1 is a polyarylate resin film (U Polymer R Unitika xi) with a thickness of 200 μm, heated to about 550°C to soften it, and then formed into a honeycomb-like uneven shape with a diameter of VK19 ex and a height of 6 cm by vacuum-pressure forming. It is a core material with a large number of cells. In the figure, the notched black cells 3 and white cells 4 mutually form unevenness. 5 is an air passage through which the black cells 3 communicate with each other, and 6 is an air passage through which the white cells 4 communicate with each other. 2 is a surface plate made of aluminum foil having a thickness of 20 PL, which is thermally bonded to both sides of the stone plate 1 using a hot melt adhesive. The bonding temperature was 180° C. and the bonding time was 30 seconds.

Since the diaphragm of the present invention has the above-described structure, even if the cells 3 and 4 formed by the many irregularities formed on the stone plate 1 are sealed on both the upper and lower sides by the surface plate 2, the air passages 5 and 6 prevent the diaphragm from moving. It communicates with the outside air from the peripheral end face. Therefore, the air pressure inside the nicum cell does not change due to changes in air temperature, temperature rise of the equipment during use, or thermal bonding during manufacturing, so unevenness does not occur on the surface plate, achieving the intended purpose of the present invention. It has the effect of Figure 5 is a graph showing the results of a rounded experiment to confirm the effects of the present invention.
a is a flat speaker using the diaphragm of the present invention; b is a first speaker;
The sound pressure frequency characteristics of a nine-plate speaker using the diaphragm shown in the figure are shown. Note that the diameter of each speaker is 253 mm. As shown in the same graph, it can be seen that α has excellent sound pressure characteristics in the high frequency band compared to Todoroki.

[Brief explanation of drawings]

Figure 1: A diagram showing a conventional flat plate diaphragm, (A) is a plan view, IP) is a side view, and (2) is a diagram showing an embodiment of the flat plate diaphragm of the present invention.
←) is an enlarged sectional view of the MU B line, and f→ is an enlarged sectional view of the OD line. Graph comparing the sound pressure frequency characteristics of [Symbols] 1. -Stone plate, 2..Surface plate, 3.4...Honeycomb cell, 5.6..Air passage, -
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Claims (1)

[Claims] In a flat diaphragm in which a surface plate made of light metal foil or plastic film is attached to both sides of a core root in which a large number of cells are formed in a honeycomb shape or a lattice shape using a film of thermoplastic synthetic resin, the large number of cells are mutually connected to each other. A diaphragm for a flat speaker, characterized in that the diaphragm has an air passage communicating with the air, and communicates with the outside air at a peripheral end face of the flat diaphragm.