JPH0450690B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a self-illuminated membrane switch, and more particularly to a self-illuminated membrane switch having a portion that self-illuminates and displays input to the switch. It is something.

<Prior Art> Conventionally, this type of switch has been constructed by disposing a thin display element such as electroluminescent, electrochromic, or liquid crystal in contact with the operating section of the touch switch, and the display surface of the display element is There is a self-illuminated switch that is configured to function by touching the switch and at the same time illuminate and display the operation of the switch.
(Refer to Publication No. 71519).

FIG. 3 shows a sectional view of the conventional self-illuminated switch.

8 is a touch panel electrode, 9 is a glass substrate, 1
0 is a transparent electrode (display electrode), 11 is an opaque electrode (counter electrode), 12 is a liquid crystal, and 13 is a spacer.

<Problems to be Solved by the Invention> However, the self-illuminated switch has the following problems.

(a) Since it is a combination of a touch switch and a flat display such as an ELD, ECD, or LCD, although it is thinner than conventional self-illuminated switches, it is not sufficient.

(b) Since it uses a flat display such as ELD, ECD, or LCD as a display element, it is expensive.

(c) Productivity is poor because the touch switch and flat display must be manufactured separately.

and so on.

<Means for Solving the Problems> In view of the above-mentioned points, the present inventor has made efforts to obtain a self-illuminating switch that can be made thin, does not require expensive materials, and has excellent productivity. As a result of repeated efforts, the present invention was finally completed. That is, in the present invention, two transparent films 2 on which transparent electrode patterns 3 are formed are pasted together via a spacer 4 with the transparent electrode pattern 3 side facing inside, and a temperature change is applied to the lower surface of the transparent input sheet 1. A thermosensitive color-changing ink layer 5 capable of reversibly changing color, a heating element pattern layer 6 corresponding to the transparent electrode pattern 3, and a concealing layer 7 are sequentially formed,
By inputting to the transparent input sheet 1, a portion of the heating element pattern layer 6 corresponding to the input portion generates heat, and the heat-sensitive color-changing ink layer 5 on the heating element pattern layer 6 partially changes color due to the heat generation. This is a self-illuminating membrane switch that is characterized by:

Hereinafter, the present invention will be explained in more detail using the drawings.

FIG. 1 shows a sectional view of a self-illuminating membrane switch according to the present invention.

1 is a transparent input sheet, and this transparent input sheet 1 is composed of a transparent film 2, a transparent electrode pattern 3, and a spacer 4.

There are various forms of this transparent input sheet 1, but for example, a striped transparent electrode pattern 3 is formed on a transparent film 2, and the transparent Generally, they are bonded together with a spacer 4 interposed therebetween, with the surface on which the electrode pattern 3 is formed facing inside.

Examples of the transparent film 2 include polyester film, polycarbonate film, and polyacrylic film. The thickness of the transparent film 2 used is in the range of 50 μm to 300 μm.
If it is less than 50 μm, it will have poor strength as a switch element, causing problems in terms of lifespan and reliability, and if it exceeds 300 μm, it will have poor transparency and flexibility as a switch element, resulting in poor operability. This is because there is a problem with this. Especially within the above range, 75μm
A range of ~200 μm is preferred.

As the transparent film 2, it is preferable to use one that has been subjected to anti-reflection treatment such as a hard coat.

The transparent electrode pattern 3 is made of indium oxide,
Formed using tin oxide, ITO, etc. The layer thickness of the transparent electrode pattern 3 is 10 Å to 2000 Å, preferably 100 Å to 1000 Å. this is,
If it is less than 10 Å, the electrical resistance as a switch element will be high and its strength will be poor, and if it exceeds 2000 Å, the transparency as a switch element will be poor and the cost for forming a transparent electrode pattern will increase. be.

Methods for forming the transparent electrode pattern 3 include methods using vapor deposition, sputtering, and the like.

Note that characters, patterns, etc. for input may be formed on the upper surface of the transparent input sheet 1.

A thermosensitive color-changing ink layer 5 is formed on the lower surface of the transparent input sheet 1.

The heat-sensitive color-changing ink layer 5 is formed using an ink that reversibly changes to various colors depending on temperature changes. Examples of such inks include heat-sensitive liquid crystal inks. This heat-sensitive liquid crystal ink has the property of reversibly changing color due to temperature changes caused by heating. This heat-sensitive liquid crystal ink is made by microcapsulating cholesteric liquid crystal or chiral nematic liquid crystal and dispersing it in a suitable solvent. A characteristic of the heat-sensitive liquid crystal ink is that it selectively reflects light in a certain wavelength range depending on the temperature, and by utilizing this property to control the temperature of the liquid crystal ink layer, the alignment of liquid crystal molecules can be improved. By changing its structure, it is possible to reproduce desired colors in the visible spectrum.

The layer thickness of this heat-sensitive color-changing ink layer 5 differs depending on the ink material used. When the heat-sensitive liquid crystal ink is used, the thickness is preferably 5 μm to 200 μm, preferably 10 μm to 50 μm. If it is less than 5 μm, the microcapsule particles in the heat-sensitive liquid crystal ink will not be completely buried in the ink layer, resulting in poor strength and stability of the ink layer, and if it exceeds 200 μm, discoloration due to temperature changes will occur. This is because the response characteristics deteriorate.

Methods for forming the heat-sensitive color-changing ink layer 5 include a printing method, a coating method, and the like.

The heat-sensitive color-changing ink layer 5 may be formed on the entire surface of the transparent input sheet 1 using the same ink, or may be formed using inks that change colors differently. For example, in FIG. 2, the "PLAY" section may be blue and the "REC" section may be red.

Note that if color ink is used as the ink for the heat-sensitive color-changing ink layer 5, multi-color printing is easily possible.

A heating element pattern layer 6 is formed on the lower surface of the heat-sensitive color-changing ink layer 5.

The heating element pattern layer 6 is formed to correspond to the input portion of the transparent input sheet 1. The heating element pattern layer 6 may be formed using nichrome, tungsten, or the like by a vapor deposition method, a sputtering method, or the like, or it may be formed using a conductive resistive paste by a printing method or the like.

The heating element pattern layer 6 is configured so that a portion corresponding to the input portion generates heat when input to the transparent input sheet 1 is input. In order to do this, for example, the extraction electrode circuit from the heating element pattern layer 6 and the transparent electrode circuit of the transparent input sheet 1 may be connected via a control circuit (not shown). Furthermore, by setting in advance several different calorific values of the heating element pattern layer 6, that is, several different heating temperatures, it becomes possible to easily display multiple colors using the same heat-sensitive color-changing ink.

A black or dark-colored concealing layer 7 is formed on the heating element pattern layer 6.

This is because the coloring mechanism of the heat-sensitive color-changing ink layer 5 is
This is due to selective reflection of specific wavelengths, and it is necessary to absorb unnecessary wavelength ranges.

In addition, in FIG. 1, 14 indicates a back sheet. It is also possible to use this back sheet 14 in place of the concealing layer 7.

<Function> Next, the function based on the self-illuminated membrane switch having the above configuration will be explained.

Input from a desired input section on the transparent input sheet 1. This input generates heat in the heating element pattern layer 6 formed in the portion corresponding to the input portion. Due to this heat generation, the heat-sensitive color-changing ink layer 5 that is in contact with the heat-generating portion is heated and changes color to a predetermined color. As a result, it is possible to make the switch of a desired part function, and also to display the input to the input section for self-reflection.

<Effects of the Invention> Since the present invention has the above configuration, it has the following effects.

(a) As a display element, a flat display such as ELD, ECD, LCD, etc. is not used, but one consisting of a heat-sensitive color-changing ink layer and a heating element pattern layer is used. Therefore, it can be configured to be extremely thin.

(b) The flat display described above is not used as a display element, but only heat-sensitive color-changing ink and a heating element are used. Therefore, it can be manufactured at extremely low cost.

(c) The manufacturing process of display elements and touch switches is
Possible consecutively. Therefore, it can be manufactured with high productivity.

(d) The switch according to the present invention is highly flexible and thin. Therefore, it has excellent ease of assembly into various devices.

and so on.

Therefore, the present invention is a self-illuminating membrane switch that is extremely useful and valuable as an input switch for computer terminals such as OA and FA, or as an input switch for consumer use.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the present invention, FIG. 2 is a perspective view of an embodiment of the present invention, and FIG. 3 is a sectional view of a conventional self-illuminated switch. In the figure, 1...Transparent input sheet, 2...Transparent film, 3...Transparent electrode pattern, 4...Spacer, 5...Thermosensitive color-changing ink layer, 6...Heating element pattern layer, 7... Hiding layer , 14...back sheet.

Claims (1)

[Scope of Claims] 1. 22 transparent films on which transparent electrode patterns 3 are formed are bonded together via spacers 4 with the transparent electrode pattern 3 side on the inside, and a transparent input sheet 1 is attached to the bottom surface of the transparent input sheet 1. Thus, a reversibly color-changeable thermosensitive color-changing ink layer 5, a heating element pattern layer 6 corresponding to the transparent electrode pattern 3, and a hiding layer 7 are sequentially formed, and the transparent input sheet 1
The heat-sensitive color-changing ink layer 5 on the heating element pattern layer 6 is partially discolored by the input to the heating element pattern layer 6, which generates heat in a portion of the heating element pattern layer 6 corresponding to the input part. Self-illuminated membrane switch. 2. The self-illuminating membrane switch according to claim 1, wherein the heat-sensitive color-changing ink layer 5 is made of heat-sensitive liquid crystal ink.