JPH02126525A - Touch panel - Google Patents

Abstract

PURPOSE:To improve the resolution without losing the visibility of an input side by mixing a filler made up by covering an unfoamed foaming agent with an expansible resin layer into a dot spacer and making the foaming agent foam after this dot spacer is printed. CONSTITUTION:A filler made up by covering an unfoamed foaming agent is mixed into resin paste; and this is printed like dots on an upper electrode 3 or a lower electrode 6. After printing, the foaming agent is heated to make it foam; then, the filler 11 expands and becomes large, so that it is possible to hold down the diameter of a dot spacer 9 to a smaller size and concurrently increase a height up to as long approx. a gap length as required. Thereby, a reduction of visibility at the input side can be decreased, and the resolution increases, and a touch panel with high reliability in insulation can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a touch panel that is used by being attached to the front side of a display device such as a CRT, or used simply as a transparent switching element.

[Conventional technology]

FIG. 3 is a sectional view of a touch panel according to a conventional example, and in the same figure, 1 generally indicates an upper sheet, and the upper sheet includes a transparent film 2 made of polyester or the like, and an ITO film formed at a predetermined position on the lower surface of the transparent film 2. It consists of a transparent upper electrode 3 such as. Reference numeral 4 generally indicates a lower sheet, and the lower sheet 4 also includes a transparent film 5 made of polyester or the like and a transparent lower electrode 6 made of ITO or the like formed at a predetermined position on its upper surface. 7 is a dot spacer printed on the lower electrode 6 at a predetermined distribution density, and the upper sheet 1 and the lower sheet 4 are joined at the periphery via these dot spacers 7.
It is integrated. 8 is a transparent holding plate made of glass, acrylic resin, etc., and is attached to the above-mentioned upper sheet 1. Dot spacer 7
The laminate consisting of the lower sheet 4 and the lower sheet 4 is placed and fixed on the holding plate 8 using an adhesive or the like (not shown).

The touch panel configured in this manner is attached to a display surface of a display device such as a CRT and used as a coordinate input device. That is, when an arbitrary position on the upper sheet 1 is pressed with a pen, a finger, or the like, the upper electrode 3 at the pressed part descends and comes into contact with the lower electrode 6, thereby detecting the coordinate position of the pressed point. When the pressing force is removed, the upper sheet 1 returns to the state shown in FIG. 5 due to the restoring force of the transparent film 2, and the picture electrodes 3.6 are kept separated again.

[Problem to be solved by the invention]

By the way, in the touch panel configured as described above, the required gap between the upper electrode 3 and the lower electrode 6 is secured by the dot spacer 7, but the dot spacer 7 is made of polyester, epoxy, etc. Since the resin paste is formed on either one of the picture electrodes 3.6 by printing technology, the diameter of the bottom surface of the dot spacer 7 tends to be considerably larger than the height dimension due to the viscosity of the resin paste. be. Therefore, in order to obtain the required gap length, each dot spacer 1-spacer 7 inevitably becomes larger, and the outline of the dot spacer 7 is viewed from the outside, which not only reduces visibility but also Electrode 3
, 6 increases the dead zone that prevents the contact, and the resolution for detection decreases.

Therefore, an object of the present invention is to solve the problems of the prior art described above, and to provide a touch panel with high resolution without impairing the visibility of the input surface.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an arrangement in which an upper electrode and a lower electrode each having translucency are laminated with a synthetic resin dot spacer printed on one or both of these electrodes. In the touch panel configured to detect the coordinates of the pressed part of the upper electrode, a filler made of an unfoamed foaming agent coated with a stretchable resin layer is mixed into the dot spacer, and the dot spacer is It is characterized in that the foaming agent is foamed after printing.

[Effect]

A filler made by covering an unfoamed foaming agent with a stretchable resin layer is mixed into the resin paste, and this is printed in dots on the upper electrode or the lower electrode. In this case, the height dimension of each printed dot spacer can be much smaller than the final gap length required between the upper and lower electrodes, and the diameter of the bottom of each dot spacer can be monitored. It can be made to a small size that is difficult to handle. Then, when the foaming agent is heated and foamed after printing, the filler expands and becomes larger, so the dot spacer can increase the height to the required gap length while keeping the diameter small. can do.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view of a touch panel according to an embodiment of the present invention, and parts corresponding to those in FIG. 3 are given the same reference numerals. As shown in 1M, the upper sheet 1 with the upper electrode 3 formed on the lower surface of the transparent film 2 and the lower sheet 4 with the lower electrode 6 formed on the upper surface of the transparent film 5 are formed using a sealing material (not shown). The sheets 1 and 4 are joined and integrated together at their peripheral edges, and a large number of dot spacers 9 are interposed between the sheets 1 and 4 to regulate the gap length between the picture electrodes 3 and 6. These dot spacers 9 include a spacer resin 10 made of a U-curing type epoxy resin, etc.;
The filler 11 is made by covering a blowing agent 12 such as isobutane with a resin layer 13 having excellent elasticity such as polyvinylidene chloride. The dot spacer 9 is formed by printing on the lower electrode 6, and the process will be explained below with reference to FIG.

First, a predetermined amount of unfoamed filler 11 is added to the spacer resin 10, and this is applied to the lower seam 1-1 using a mask (not shown).
4 to form dot spacers as shown in FIG. 2 fa). In this case, the particle size of the filler 11 with the foaming agent 12 in an unfoamed state is as small as 10-odd μm, and the height of the dot spacer is sufficiently smaller than the required gap length. The dot spacer is printed so that the diameter 2 of the bottom surface is sufficiently smaller than that of a conventional dot spacer.

Thereafter, when this lower seam 1-4 is heated in a heating furnace, the foaming agent 12 foams and the filler 11 expands to about 50 μm, as shown in FIG. When the resin is cured, the dot spacer 9 shown in Fig. 1 is obtained.The dot spacer 9 thus obtained has a bottom diameter p that does not change and a height dimension h2.
Since only the gap length changes to the same extent as the required gap length, the height dimension h2 is sufficiently larger than the diameter l of the bottom surface.

The remaining configuration and functions of the touch panel according to this embodiment are as follows.
Since it is similar to the conventional example shown in FIG. 3, a description thereof will be omitted.

In the above embodiment, the dot spacer 9 interposed between the upper electrode 3 and the lower electrode 6 has a larger height than the diameter of the bottom surface, so that the required gap length can be reduced. When securing the dot spacer 9, the dot spacer 9 can be made much smaller than the conventional technology, and therefore, the dot spacer 9 is hardly visible from the outside, and the visibility of the touch panel can be improved. can. In addition, the driver I spacer 9 with a small bottom diameter like this
Therefore, the non-contact portions of the picture electrodes 3 and 6, that is, the input dead zone, are reduced, and the resolution for coordinate detection can be improved.

In the above embodiment, the dot spacer 9 is connected to the lower electrode 6.
Although we have described the case in which the dot spacers 9 are printed on the side of the dots, the same effect can be achieved even if the dot spacers 9 are printed and formed on the upper electrode 3 side instead of the lower electrode 6, or distributed to the picture electrode 3.6. Not even.

〔Effect of the invention〕

As explained above, according to the present invention, the dot spacer can be printed in a shape that is sufficiently large in height compared to its diameter, so there is little deterioration in the visibility of the input surface, high resolution, and insulation. We can provide highly reliable touch panels.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of a touch panel according to an embodiment of the present invention, FIG. It is a sectional view of a touch panel. ■...Top sheet, 2,5...Transparent film, 3...Top electrode, 4...Bottom sheet, 6...Bottom Electrode, 8... Holding plate, 9... Dot spacer, IO...
Spacer resin, 11... Filler 12...
...Blowing agent, 13...Resin layer. Figure 2

Claims (1)

[Claims] An upper electrode and a lower electrode each having translucency are laminated with a dot spacer made of synthetic resin printed on one or both of these electrodes, and the coordinates of the pressed part of the upper electrode are detected. The touch panel is characterized in that a filler made by covering an unfoamed foaming agent with a stretchable resin layer is mixed into the dot spacer, and the foaming agent is foamed after printing the dot spacer. touch panel.