JPH0418628A - Touch panel - Google Patents

Abstract

PURPOSE:To improve the transmissivity of light, to make interference stripes or waveform deformation hard to be generated, and to reduce dispersion in the resistance value of a transparent electrode by providing an external member adhering and laminating glass plates without opening on the outside of a resin sheet for this touch panel. CONSTITUTION:A transparent conductive film 5 is formed on one side of a polyethylene terephthalate film 4. On the other side, a polyethylene terephthalate film 2 having a hard coating layer 1 on the one side is wholly adhered through an adhesive 3 while directing the layer 1 side to the outside so as to obtain a laminated object B. Resist is applied onto the film 5 of this object B, and pattern is exposed. After an etching processing, the resist is peeled off, and the electrode is formed. After forming a lead electrode by silver paste printing, the adhesive agent is applied and an adhesive layer is formed so as to obtain an input side resin sheet C. After applying the resist onto the transparent conductive film 5 of the film 9, the back side is adhered through an adhesive layer 10 to a glass plate 11, an electrode is formed by exerting the etching processing onto the resist layer so as to obtain an opposite side resin sheet E. Then, the touch panel is obtained by press-fixing the sheets C and E.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a conductive film contact type touch panel which has a resin sheet in which glass plates are laminated without gaps, and which has excellent input accuracy, visibility, and durability.

Conventional Technology and Problems Conductive film contact type touch panels, which have a transparent substrate with a transparent electrode made of a transparent conductive film on one side facing each other with the transparent electrode side facing inside, are used on various display devices, menu boards, etc.
For example, it is put into practical use in systems that operate the main body of the device by stacking it on a CRT, liquid crystal cell, plasma type, or electroluminescence type. For example, the input may be performed by pressing or tracing a target point or area displayed on the device from the surface with a finger or pen, etc., bringing opposing transparent electrodes into contact with each other, and directly inputting the position data. It will be done.

Conventionally, the transparent substrate on the side opposite to the input side of such a touch panel is a transparent insulating resin sheet having a transparent electrode made of a transparent conductive film on one side and a transparent reinforcing sheet placed on the other side without adhesion. However, as a transparent substrate on the input side, one provided with a hard coat layer was known.

However, in the former method in which the transparent reinforcing sheet is placed without adhesive, light interference fringes occur on the touch panel due to misalignment of the transparent reinforcing sheet and gaps between it and the resin sheet, and the interface with air inside the touch panel is As a result, reflection loss increases, light transmittance decreases, and display visibility deteriorates. On the other hand, in touch panels whose input side is made of a resin sheet with a hard coat layer,
In addition to having low surface hardness, the resin sheet is deformed into a wave shape and has poor surface flatness, and large-sized displays exceeding 84 plates have poor visibility and appearance, and improvements in this point are desired.

On the other hand, a glass plate having a transparent electrode made of a transparent conductive film was also known as the above-mentioned transparent substrate (Japanese Patent Application Laid-Open No. 1828-1883).
Publication No. 29). However, it is difficult to form a transparent conductive film with a uniform thickness due to problems such as cracking, poor handling, and bending when glass plates are thin, and the resistance value of transparent electrodes within each glass plate or between glass plates tends to vary. There was a problem: Variations in the resistance value of the transparent electrodes could lead to errors in detecting the input position, which is a fatal problem for analog input type touch panels used for handwriting input and digitizer applications.

Means for Solving the Problems The present invention overcomes the above problems by forming a transparent substrate with an adhesive laminate of a resin sheet and a glass plate without any gaps.

That is, the present invention is formed by disposing a transparent insulating resin sheet having a transparent electrode made of a transparent conductive film on one side with the transparent electrode side facing inside and facing each other with a spacer interposed therebetween.
The present invention provides a touch panel characterized in that at least one of the opposed resin sheets has a glass plate adhered to the outside without a gap via a transparent adhesive layer.

By forming a touch panel with a laminate in which a glass plate is adhered to a resin sheet without any gaps, a transparent conductive film with excellent film thickness uniformity can be efficiently formed using a long resin sheet. Since there is no change in resistance distribution, it is possible to efficiently form transparent electrodes or touch panels with small variations in resistance value, and it is also possible to prevent the increase of air layer in the touch panel, light interference, and decrease in transmittance, making it possible to form touch panels on the touch surface. It is also possible to provide sufficient hardness. In addition, the adhesion through the transparent adhesive layer suppresses the waveform deformation of the resin sheet while maintaining the appropriate deformability necessary for input, and the glass plate is less likely to break due to good stress relaxation properties, improving handling and input. Even if the glass plate breaks due to pressure, it will not scatter.

Embodiment The touch panel of the present invention uses a transparent insulating resin sheet with a glass plate laminated on one side thereof with a transparent adhesive layer interposed therebetween. Its structure is illustrated in FIGS. 1-3. 1 is a hard coat layer, 2 is a transparent reinforcing sheet,
3.10.13.17.20 is a transparent adhesive layer, 4.9.1
4.15.18.19 is a resin sheet, 5 is a transparent electrode made of a transparent conductive film, 6 is a spacer, 7 is a lead electrode, 8.
82 is an adhesive layer, 81 is an insulating layer, 11.12.16.21
is a glass plate. As is clear from the rotation, in the present invention, the glass plate adhesively laminated with the resin sheet only needs to be present on at least one of the external sides of the touch panel.

The touch panel is formed through a manufacturing process that includes, for example, the process of forming transparent electrodes, the process of bonding and laminating resin sheets and glass plates, and the process of bonding resin sheets on the input side and the opposite side with spacers interposed. be able to.

For example, transparent electrodes can be formed by removing unnecessary parts of a transparent conductive film provided on a resin sheet by etching using a resist, or by forming a transparent conductive film on a resin sheet by sputtering or vapor deposition. Methods of forming patterns using metal masks, etc., methods of pattern coating with conductive polymers such as polyaniline, and methods of blending transparent conductive powders such as indium-tin composite oxide with transparent resins such as epoxy and acrylic resins. Examples include a method of pattern coating a dispersed paste made of Examples of the material for forming the transparent conductive film using the sputtering method or vapor deposition method include indium-tin composite oxide, tin oxide, gold, palladium, and the like. Note that the pattern of the transparent electrode is appropriately determined depending on the input method, etc., and for example, it is formed in a solid state in the case of an analog method, and in a striped state in the case of a digital method. The examples shown in FIGS. 1 to 3 above are of the analog input type formed in a solid shape.

As the resin sheet, for example, a transparent and insulating material made of poly, ester, polyethersulfone, polyetheretherketone, polyetherimide, etc. is used. The thickness is generally 10 to 500 μm, but is not limited thereto. When forming a transparent conductive film, especially when using a sputtering method or a vapor deposition method, a long resin sheet is used before being laminated with a glass plate, and a transparent conductive film is continuously formed thereon. This method is advantageous in achieving uniform thickness and mass production. In addition, a long resin sheet with a transparent conductive film on the entire surface of one side is
It is preferably used for efficient assembly or manufacturing of touch panels, and is especially advantageous for forming analog input type touch panels.

A lead electrode is provided for the transparent electrode.

The formation may be performed by an appropriate method such as a printing method using silver paste, carbon paste, or the like. The lead electrode can be formed at an appropriate stage, such as after forming the transparent electrode, or before bonding the resin sheets on the input side and the opposite side.

The glass plate to be adhesively laminated with the resin sheet should have a thickness of 0.05 to 0.5 mm H on the input side of the touch panel, and a glass plate of 0.1 to 10 mm thick on the opposite side due to input properties, reinforcement properties, etc. It is preferable.

The glass plate is adhesively laminated with the resin sheet through the transparent adhesive layer without any gaps. For the adhesion, an appropriate transparent adhesive such as an acrylic adhesive or a silicone adhesive may be used. The lamination process may be performed by an appropriate method such as a roll lamination method or a lamination press method.

There is no particular limitation on the order of the adhesive lamination process of the resin sheet and the glass plate. This can also be done after bonding the resin sheets on the input side of the touch panel and the opposite side. When forming transparent electrodes by etching unnecessary portions using a resist, it is recommended to perform the process in an appropriate step after applying a resist onto a transparent conductive film provided on a resin sheet using a printing method, etc. to improve manufacturing efficiency. It is preferable in this respect.

As illustrated in FIG. 4, the resin sheets 4.9 on the input side of the touch panel and the opposite side are bonded with a spacer 6 interposed therebetween. The dot spacer can be interposed by placing a dot spacer or a particle spacer on the surface of the transparent electrode, or by adding a layer of a fluid material such as a gel material.The dot spacer may be made of silicone resin, epoxy resin, etc. It can be formed by molding an insulating transparent resin such as acrylic resin into a circular head shape and scattering it using a pattern printing method, a dispenser type, etc. Particle spacers are, for example, particles made of an inorganic or organic material. It can be formed by spraying or applying a dispersion of fiber particles or spherical particles with a diameter of about 0.1 to 100 μm and drying.Even if the particles as spacers are movable within the space, good.

For adhesion of the resin sheets on the input side and the opposite side, for example, the edge of at least one resin sheet is made of acrylic,
An appropriate method may be used, such as a method in which an adhesive layer made of an epoxy-based adhesive, a silicone-based adhesive, or a pressure-sensitive adhesive, which also serves as a spacing material, is provided and bonded. The spacer can also serve as an insulating layer provided as necessary at the edge of the transparent electrode or lead electrode in the resin sheet on at least one of the input side and the opposite side. The insulating layer can be formed using, for example, an appropriate resin such as an acrylic resin, an epoxy resin, or a silicone resin.

Example 1 A transparent conductive film (thickness: 300 μm) made of indium-tin composite oxide was continuously formed on one side of a long polyethylene terephthalate film with a thickness of 75 μm using a reactive sputtering method.

On the other side of the polyethylene terephthalate film A obtained above, a long polyethylene terephthalate film having a thickness of 75 μm and having a hard coat layer (thickness 2 μm) made of silicone resin on one side was placed with the hard coat layer side facing outward. A laminate body B was obtained by continuously adhering the entire surface using an acrylic adhesive (thickness: 2 hm).

A resist (
NAZ-DAR231 (manufactured by Yoshikawa Kako Co., Ltd.) was applied and exposed in a pattern, and after etching (3% hydrochloric acid) treatment, the etching resist was peeled off (3% caustic soda) to form hollow transparent electrode units at predetermined intervals. and silver paste (Electrodag 423 manufactured by Nippon Acheson Co., Ltd.).
ss) to form lead electrodes for each transparent electrode part, then insulating resin (manufactured by Nippon Acheson Co., Ltd., ML25094
) to form an insulating layer on the edges of each transparent electrode and lead electrode, and an adhesive (manufactured by Jujutsu 3M Co., Ltd., 5).
P-I-1i-T) was applied to form an adhesive layer, and a resin sheet C at the input end consisting of a long body was continuously obtained.

On the other hand, after continuously coating a resist on the transparent conductive film of the long polyethylene terephthalate film A, the long body is cut into a predetermined size and a thickness of l is applied through the back side.
The entire surface of the laminated plate was adhesively laminated on a 1 mm glass plate via an acrylic adhesive layer with a thickness of 20 μm, and the resist layer on the formed laminated plate was etched as described above to peel off the etching resist, and the transparent electrode was formed. After providing a lead electrode made of silver paste and forming an insulating layer on the edges of the transparent electrode and the lead electrode, epoxy resin is applied in a pattern to form a dot spacer in the shape of a circular head. A resin sheet E was obtained.

Next, the resin sheet C was crimped to the resin sheet E through the adhesive layer, and a connector was attached to this according to a conventional method, and then the outer shape was processed so that the effective area was 20 x 20 cm.
? I got the analog input type Yu/Sochino (Nel).

Example 2 According to Example 1, after applying a resist to forming an insulating layer on the transparent conductive film of the long polyethylene terephthalate film A, the formed long polyethylene terephthalate film F was cut and the back surface was cut. A resin sheet G on the input side is laminated with adhesive on the entire surface of the glass plate with a thickness of 0.15 mm through an acrylic adhesive layer with a thickness of 20 rJm, and a glass plate with a thickness of 20 μm is placed on a glass plate with a thickness of 1.1 + nm.
The entire surface is adhesively laminated via an acrylic adhesive layer to form the opposite resin sheet H, an adhesive layer is provided on the edge of the resin sheet G, and dot spacers are formed on the resin sheet H to adhere them. , we obtained an analog input type touch panel.

Comparative Example 1 A long polyethylene terephthalate film with a thickness of l 50 μm and a hard coat layer provided on one side, on the other side,
After forming a transparent conductive film and forming an adhesive layer in accordance with Example 1, the sheet was cut into a predetermined size to obtain an input-side sheet I.

On the other hand, on one side of a long polyethylene terephthalate film having a thickness of 188 μm, the steps from forming a transparent conductive film to forming dot spacers were performed according to Example 1, and then the film was cut to obtain a sheet J on the opposite side.

Next, the sheet I and the sheet J are crimped together, a connector is attached and the external shape is processed, and the sheet J is given a thickness of 1.
An analog input type touch panel was obtained by adhering and laminating glass plates of No. 1 (Incorporated) through a 20 μm thick acrylic adhesive layer provided in the shape of a frame.

Comparative Example 2 A transparent conductive film made of indium-tin composite oxide was formed on one side of a 0.2 mm thick glass plate cut into touch panel forming dimensions by a reactive sputtering method, and then the transparent conductive film was The steps from applying a resist to forming an adhesive layer were performed on the substrate in the same manner as in Example 1, to obtain a glass substrate on the input side.

On the other hand, using a glass plate with a thickness of 1.1 mm, the steps from forming a transparent conductive film to forming dot spacers were performed according to Example 1 to obtain a glass substrate on the opposite side.

Next, the glass substrates on the input side and the opposite side were crimped, a connector was attached, and the external shape was processed to obtain an analog input type touch panel.

The following characteristics of the touch panels obtained in the evaluation test examples and comparative examples were investigated.

[Transmittance] Using a spectroscopic analyzer (manufactured by Shimadzu Corporation, UV-240),
The transmittance of light at a wavelength of 550 nm was measured.

[Interference fringes] Judgment was made visually.

[Linearity] The voltage in the X and Y directions at each part of the touch panel was measured at 5-meter intervals using the circuit shown in FIG. 5, and the voltage was determined based on the following equation using each measured value.

The touch panel was allowed to drop three times with the input side facing up from a position with a linearity height of 75 cm, and evaluation was made as ◯ if there was no cracking in any case, and × if cracking occurred in any of the cases.

÷3362 xlooo However, as shown in Figure 6 (, △Vi is the difference between the measured value at each measurement point and the value on the regression line, V^, VB
are the measured values at the starting and ending points of the regression line.

Note that the smaller the calculated value of the linearity, the smaller the variation in the resistance value of the transparent electrode.

[Pencil hardness 1 Input side of touch panel evaluated by pencil scratch test according to Nikki JIS K 5400.

[Natural drop test] Thickness 4 cm, size 40 x 40 cm? The above results were shown in the table on a smooth maple board.

Effects of the Invention The touch panel of the present invention uses a glass plate laminated on the outside of a resin sheet with no gaps as an external member, so it has excellent light transmittance, is hard to cause interference fringes or waveform deformation, and has excellent visibility. ing. Further, the variation in the resistance value of the transparent electrode is small, and even when an analog type is used, it is difficult to misidentify input data. Furthermore, the glass plate is hard to break, has excellent durability, and has excellent surface hardness when used on the input side.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are sectional views of other embodiments, Figure 4 is an explanatory diagram of the input side and the opposite side when bonded, and Figure 5
The figure is an explanatory diagram of the linearity test method, and FIG. 6 is an explanatory graph showing an example of measurement in the X direction of the evaluation method. 4.9.14.15.18, I9: Resin sheet 5: Transparent electrode 6: Spacer 10.13.17.20: Transparent adhesive layer 11.12.16.21 Ni glass plate Patent applicant Representative of Nitto Denko Corporation People Tsutomu Fujimoto

Claims (1)

[Claims] 1. Transparent insulating resin sheets having a transparent electrode made of a transparent conductive film on one side are arranged facing each other with the transparent electrode side facing inside, with a spacer interposed therebetween, and at least one of the resin sheets arranged oppositely. A touch panel characterized in that the touch panel has a glass plate adhered to the outside without a gap via a transparent adhesive layer.