JP2000285760A - Lighting sheet-like key top - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain reduction in cost and reduction in thickness and weight by forming a dispersion type EL, consisting of a transparent electrode layer that is an organic polymer layer, a compensating electrode layer, an emitter layer, a dielectric layer, a back face electrode layer, and an insulating layer on the lower surface of a resin film curved in the same form as a resin-made key top body and formed integrally on the upper surface side thereof. SOLUTION: A display part 2 of characters or patterns is formed on the reverse face of a light transmissive resin film 1 by screen printing. A transparent electrode layer, that is an organic polymer layer, a compensating electrode layer, emitter layer, dielectric layer, back face electrode layer, and insulating layer are successively formed on the whole reverse face of the resin film 1 which has the display part 2 to form the part of an EL 4. The resin film 1 having the display part 2 and the EL 4 is set in an injection molding die, and the resin film 1 is curved by the pressure of the melted resin to form a key top body 3. According to this, the structure is simplified, the number of part items is reduced, and the display part 2 can be lighted with high luminance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminated sheet-like key top for a key top in various electronic devices such as a telephone, a personal computer keyboard, and a controller.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller and more portable,
Demands for downsizing, thinning, and weight reduction of switches used in the operation section are also increasing. Conventionally, as a key top used for miniaturization, thinning, and weight reduction, as shown in FIG. 2, on a top surface side of a resin key top body,
There is a sheet-like keytop in which a light-transmitting resin film curved in the same shape is integrally formed. In a mechanism for adding an illumination function using EL to the sheet-like keytop, the keytop portion is illuminated by combining the EL below the sheet-like keytop.

[0003]

However, in the conventional illuminating mechanism, the number of parts is large and the configuration is complicated, so that the number of assembling steps is increased, and it is difficult to reduce the thickness and weight.
Further cost reduction could not be achieved. In addition, there is a problem that there is a distance between the EL and the surface of the keytop, and light passes through the keytop body made of a translucent resin, so that the light is attenuated. We also examined a test in which the conventional EL was curved into the same shape as the top surface of the key top body. However, since the transparent electrode layer of the conventional EL is an inorganic thin film formed by sputtering indium tin oxide (ITO), When the resin film is deformed into a curved shape, the resin film is stretched while being bent, so that the ITO film was broken and could not be realized.

[0004]

SUMMARY OF THE INVENTION The present invention is to solve such a conventional problem, and has a simple structure and a reduced thickness.
An object of the present invention is to provide an illuminated sheet-like key top having an illuminating mechanism capable of reducing the weight. According to the present invention, by using the EL of the transparent electrode layer which is an organic polymer layer, when the resin film is deformed, the transparent electrode layer extends while following the resin film, and the breakage of the transparent electrode layer is avoided.

That is, a light-transmitting resin film curved in the same shape is integrally formed on the upper surface side of a key top main body made of resin, and a transparent electrode, which is an organic polymer layer, is formed on the lower surface of the resin film. Layer, compensation electrode layer, luminescent layer,
This is an illuminated sheet-like keytop on which an EL essentially consisting of a dielectric layer, a back electrode layer, and an insulating layer is formed. Further, it is an illuminated sheet-like key top in which a display portion is formed on a resin film.

[0006] The transparent electrode layer, which is the organic polymer layer of the present invention, is a layer in which a light-transmitting conductive powder is dispersed in a transparent organic polymer. The light-transmitting conductive powder of the present invention includes indium tin oxide (ITO), antimony tin oxide (A
Although oxides such as (TO) are exemplified, use of ITO-based conductive powder, which is particularly excellent in conductivity and transparency, is optimal.

[0007] The transparent organic polymer of the present invention is a liquid organic polymer, and is cured by heat, light, moisture or the like to form a transparent layer. As the material, a material that adheres to a resin film or another layer is appropriately selected. In the present invention, a display portion can be provided between the resin film and the EL or on the surface of the resin film. Especially resin film and EL
In the case where the display section is provided between them, the outermost surface becomes the resin film, so that the wear resistance of the display section can be improved.

The resin of the key top body of the present invention is made of polypropylene, polyurethane, polyamide, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polystyrene,
At least one resin selected from polyacrylonitrile butadiene styrene is preferred.

The light-transmitting resin film forming the EL of the present invention includes polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, polyamide film, polyethylene naphthalate film, polypropylene film, polystyrene film, fluorine film, ionomer film, At least one resin film selected from a polycarbonate film and a polyvinyl chloride film is preferred.

The ink for printing the display portion on the light-transmitting resin film of the present invention is at least one selected from acrylic, PVC, urethane, ester, and epoxy.
One ink is preferred. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011]

FIG. 1 is a sectional view of an embodiment of an illuminated sheet-like key top according to the present invention. EL4 composed of a transparent electrode layer, a compensation electrode layer, a light emitting layer, a dielectric layer, a back electrode layer, and an insulating layer is formed only on the back surface of the display section 2 of the light transmitting resin film 1. Body 3
It is constituted by.

In the method of manufacturing an illuminated sheet-like key top according to the present invention, a display portion 2 such as a character or a figure is formed by screen printing on a light-transmitting resin film 1 with ink. Next, a transparent electrode layer, a compensation electrode layer, a luminescent layer, a dielectric layer, a back electrode layer, and an insulating layer are sequentially formed on the resin film 1 having the display section by screen printing, thereby forming a portion of EL4. . Next, the resin film having the display portion and the EL is set in an injection mold, and the resin film is bent by the pressure of the molten resin to form the key top body 3. At this time, the resin film and the key top body may be brought into close contact with each other by heat fusion, or may be brought into close contact with each other via an adhesive layer.

[0013]

Example 1 On a back surface of a resin film 1 of a polyethylene terephthalate film, a display section 2 for characters and figures was formed by screen printing using acrylic ink. next,
A transparent electrode layer (ITO-based ink manufactured by Sumitomo Osaka Cement Co., Ltd.), a compensation electrode layer (Doitite FA-312 manufactured by Fujikura Kasei Co., Ltd.) on the entire back surface of the resin film 1 having the display unit 2 by screen printing; Light-emitting layer (Doitite FEL-125 manufactured by Fujikura Kasei Co., Ltd.), dielectric layer (Fujikura Kasei Co., Ltd.)
Dotite FEL-615 manufactured by Fujikura Kasei Co., Ltd., Dortite FEC-198 manufactured by Fujikura Kasei Co., Ltd.), and an insulating layer (XB-101G manufactured by Fujikura Kasei Co., Ltd.) were sequentially formed to form EL4 portions. As the transparent electrode layer, a layer obtained by mixing a liquid organic polymer obtained by dissolving a polyester-based resin with a solvent and an ITO-based conductive powder and curing the mixture with heat was used.

Next, the resin film 1 having the display portion 2 and the EL 4 is set in an injection molding die, and the resin film 1 is bent by the pressure of the molten polycarbonate resin to form a key top main body 3. As a result, an illuminated sheet-like key top as shown in (1) was obtained. The illuminated sheet-like keytop of the present embodiment simplifies the configuration and reduces the number of parts. Further, since the illuminating surface is near the key top surface, there is almost no attenuation of light, so that it is possible to illuminate the display unit with high luminance. Also, no EL disconnection occurred during the curve forming of the resin film.

[0015]

COMPARATIVE EXAMPLE 1 On a back surface of a resin film 1 of a polyethylene terephthalate film, a display portion 2 of characters, figures, etc. was formed by screen printing using acrylic ink. next,
The resin film 1 having the display portion 2 is set in an injection mold, and the resin film 1 is bent by the pressure of the molten polyethylene terephthalate resin to form a key top main body 3 to obtain a sheet-like key top shown in FIG. Was. When the sheet-like key top of this comparative example was used in combination with a separately prepared EL, the number of parts was large, the configuration was complicated, and the number of assembling steps was large. Light was attenuated because of the distance between the EL and the key top surface.

[0016]

As described above in detail, according to the illuminated sheet keytop according to the present invention, since the sheet keytop and the EL are integrated, the structure is simple and the number of parts is reduced. As a result, it is easy to simplify the assembly process, reduce the cost, reduce the thickness, and reduce the weight. In addition, since the illuminated surface is near the key top surface, there is almost no light attenuation, so that the display unit can be illuminated with high luminance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an illuminated sheet-like key top of the present invention.

FIG. 2 is a cross-sectional view of a conventional sheet key top.

FIG. 3 is a sectional view of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin film 2 Display part 3 Key top body 4 EL

Claims (2)

[Claims] 1. A key top body made of a resin,
An optically transparent resin film curved in the same shape is integrally formed, and on the lower surface of the resin film, a transparent electrode layer which is an organic polymer layer, a compensation electrode layer, a light emitting layer, a dielectric layer,
A dispersion-type EL (hereinafter referred to as E) composed of a back electrode layer and an insulating layer
An illuminated sheet-like key top, wherein L) is formed. 2. The illuminated sheet-like key top according to claim 1, wherein a display portion is formed on the resin film.