JPH02291619A - Transparent touch panel - Google Patents

Abstract

PURPOSE:To readily form a dot spacer of sufficient height by making the synthetic resin of the dot spacer contain silica, the spacer being located between transparent conductive layers. CONSTITUTION:Between the transparent conductive layer 3 of a synthetic resin base 1 forming a transparent touch panel and the transparent conductive layer 3 of a glass base 2, a dot spacer 5 is provided on the layer 3 of the base 2. The synthetic resin of the spacer 5 is prevented from flowing after screen printing by putting micro powder of silica in the resin, and thus a dot spacer of small diameter and sufficient height is readily formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transparent touch panel, which has been in increasing demand in recent years as an input device for computers and the like. A transparent touch panel is installed on a display or the like so that input can be performed directly on an image using a finger, and is used as an input method that is easy for anyone to use.

[Conventional technology and its problems]

Conventional touch panels are made of indium tin oxide (ITO) on at least one flexible substrate.
It is made by forming two transparent conductive films each having a conductive layer formed thereon, and forming a spacer so that the transparent conductive layers face each other.

This resin spacer is epoxy-based, polyester-based,
A silicone-based, acrylic-based, polyurethane-based resin or a diluted resin solution is printed on either side of the transparent conductive film using a screen IJ stamp ml1.

The shape of this baser has a diameter of 200~! OOμ
The dot-shaped one is the most common. As for the dot spacer, it is best to use a dot spacer with a small diameter as it will stand out from the outside if it is too large, but resin spacer ink will flow after printing, so if it is too small the height will not be maintained. If the height of the dots is low, there will be enough rectangular edges,
It cannot fulfill its role as a spacer. The dot height is preferably 30-≠θμm or more when using a film with a film thickness of 2Jμm, but it is usually difficult to form dots with a high height, which is a problem for touch panel manufacturers. there were.

[Means to solve the problem]

In view of the above-mentioned circumstances, the inventors of the present invention have conducted intensive studies with the aim of forming dot spacers with a small diameter and sufficient height using a screen printing method, and have found that fine powder silica is included in the resin for dot spacers. The inventors have discovered that by doing so, it is possible to easily obtain dot spacers with sufficient height without resin flow after screen printing, and have thus arrived at the present invention.

That is, the gist of the present invention is that at least one of two transparent conductive films arranged to face each other has flexibility, and a dot spacer is provided between the transparent conductive films. The present invention relates to a transparent touch panel characterized in that fine powder silica is contained in a synthetic resin forming dot spacers.

The present invention will be explained in detail below.

FIG. 3 is a sectional view showing an example of a transparent touch panel of the present invention.

In the figure, l indicates a synthetic resin substrate (top), C indicates a synthetic resin or glass substrate (bottom), 3 indicates a transparent conductive layer, ≠ and Hiro' indicate a transparent conductive film, and j indicates a dot spacer.

The present invention is characterized in that the dot spacer resin contains finely divided silica having a particle size of j-nm.

It is preferable that the fine powder silica is contained in an amount of O, j, t based on the solid content of the dot spacer resin. The content of fine silica! If the amount is more than the weight factor, the thixotropy will be too high, which may result in an uneven shape rather than a neat hemispherical shape after screen printing.Also, since the viscosity of the resin will increase, plate omission during screen printing may become worse. There is sex. If the content of fine silica powder is less than the O3 weight ratio, it becomes difficult to obtain a sufficient dot height.

The finely divided silica may be subjected to hydrophobic treatment in order to improve its dispersibility in the dot spacer resin.

Resins for dot basers include commonly used epoxy, polyester, silicone, acrylic,
A resin such as polyurethane can be used.

In the present invention, the above spacer resin and finely powdered silica are mixed to form a screen printing ink. Screen mark 1i! The ink for II preferably has a concentration of /00% in order to minimize fading after curing, but it may be diluted with an appropriate solvent depending on the type of spacer resin, printability, etc.

The viscosity of the screen printing ink is preferably in the range of 10,000 to 1/00,000 cps, although it depends on the printing conditions.

Moreover, the mesh of the screen printing plate is preferably /10 to 2jO mesh. If the dots become rougher than this, it will be difficult to obtain a neat shape.
The finer the lines, the more likely they are to get clogged.

You may take .

In the present invention, a transparent conductive layer is formed on a synthetic resin or glass substrate to form a transparent conductive film, and dot spacers are further formed thereon by screen printing.

Examples of synthetic resin substrates include polyesters such as polyethylene terephthalate and polybutylene terephthalate; borisulfone; polyethersulfone; polyolefins such as polyethylene and polypropylene;
Commonly used substrates include vinyl polymers such as polystyrene, polyvinyl chloride, and polymethyl methacrylate; polycarbonate; and polyimide.

The transparent conductive layer can be formed by sputtering a commonly used metal thin film such as gold, silver, copper, palladium, aluminum, or tin, or a metal oxide thin film such as indium oxide, ITO, zinc oxide, or aluminum oxide onto the substrate. It is formed by laminating layers by a method such as a vacuum deposition method or a vacuum evaporation method.

The type, thickness, shape, etc. of the substrate, type, shape, etc. of the conductive layer can be appropriately selected and combined depending on the purpose.

〔Example〕

Next, the present invention will be explained in more detail by examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

Example/ A film of indium tin oxide (ITO) having a surface resistivity of 300 Ω/hole was formed by sputtering on a polyethylene terephthalate film to form a transparent conductive film. This transparent conductive film / 0 0+m
After cutting to X / 00 rpaa, printing a resist on the ITO film using screen printing, etching, and peeling off the resist to 70 mm X /
! The electrode pattern of rts I 0! μ books were formed at intervals of 1.

In addition, as a dot spacer ink, we also use dot spacer ink base material (Seiko Advance ``l6'').
20" resin concentration/00%) at a weight ratio of 7:3, and further added fine particle silica of average/Arts diameter ("AEROS I LR TA7NO" manufactured by Nippon Aerosil) to the resin solid content!,! Weight section Add and mix well to disperse.

The viscosity of the dot spacer ink thus obtained is 2
It was 2 F, 0 0 0 Cps at j'C.

Using this dot 1 spacer ink, polyester 2
00 mesh, total screen thickness/00 μm screen target value, dot baser with diameter 200 μm/
Oram interval printing was performed.

After this, heat treatment was performed at 00°C for 30 minutes to harden the dot baser ink, and the dot baser diameter was measured using a microscope (Nik On O P T I P H
Measurements were taken by attaching a micrometer eyepiece (Niko mouth) to the camera.

In addition, the dot spacer height was determined using a stylus-type film thickness meter (Fineproof Co., Ltd. "Militron/Model 202"). This test was repeated j times, and the average values at that time are shown in Table I. .

EXAMPLE Dot spacers were printed in the same manner as in Example except that dot spacers with a diameter of 200 μm were formed as the target value. The results are shown in Table 1.

Comparative Example 1 Dot spacers with a target diameter of 200 μm were printed in the same manner as in Example 1, except that fine powder silica was not used.

The viscosity of the dots baser ink after mixing the main ingredient and curing agent was 2 j ''C, ♂, roocps.

The results are shown in Table I.

Comparative Example Dot spacers with a target diameter of 200 μm were printed in the same manner as in Example 2 except that fine silica powder was not used. The results are shown in Table 1.

Table I/Table continued φ It is clear that dot spacers are formed.

〔Effect of the invention〕

According to the present invention, it is possible to easily form dot spacers having a small diameter and a sufficient height, which is industrially useful.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the touch panel of the present invention. In the figure, l is a synthetic resin substrate (top), λ is a synthetic resin or glass substrate (bottom), 3 is a transparent conductive layer, μ and μ' are transparent conductive films, and Y is a dot spacer.

Claims (1)

[Claims] (1) In a transparent touch panel in which at least one of two transparent conductive films arranged so that the transparent conductive layers face each other is flexible, and a dot spacer is provided between the transparent conductive films, A transparent touch panel characterized by containing fine powder silica in the synthetic resin forming the dot spacers.