JPH10283117A - Touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch panel with which a conduction defect does not occur even when a drag circuit generates a crack or the like between a connection part and its surroundings. SOLUTION: Concerning the touch panel of analog resistant film system using a conductive adhesive agent 12 for connecting a drag circuit 11 of the electrode sheet on the side where the drag circuit 11 is provided and a bus bar 3 of the electrode sheet 4 on the side where the drag circuit 11 is not provided, on the lower layer of the drag circuit 11, a conductive film and an independent auxiliary conductive film 13 are provided in the area of connecting the drag circuit 11 and the bus bar 3 through the conductive adhesive agent 12 and at a position overlapped with its adjacent area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of inputting a position on a screen such as an LCD (Liquid Crystal Display) or a CRT (CRT) by pressing the screen from above with a finger or a pen in accordance with an instruction on a see-through screen. Is performed on a touch panel.

[0002]

2. Description of the Related Art Conventionally, as a touch panel used for an electronic organizer or a personal computer, as shown in FIG. 3, a transparent insulating substrate 1 such as a glass plate or the like has a transparent insulating substrate 1 made of indium tin oxide (ITO) or the like. Electrode sheet 4 formed with a pair of parallel bus bars 3 made of a transparent conductive film 2 and a silver paste, and a conductive film 6 similar to the above on a transparent flexible insulating base material 5 such as a polyethylene terephthalate film. Upper electrode sheet 8 on which bus bar 7 is formed
And a spacer 9 having a dot shape or the like interposed between the conductive films 2 and 6 so that the direction between the bus bars 3 of the lower electrode sheet 4 and the direction between the bus bars 7 of the upper electrode sheet 8 are orthogonal to each other. Is an analog resistive film type in which is adhered with an adhesive layer 10 such as a double-sided tape or an insulating adhesive.

In this type of touch panel, the connection between the busbars 3 and 7 and the external terminals is usually provided by providing a circuit 11 to either the upper electrode sheet 8 or the lower electrode sheet 4. For example, when the wiring circuit 11 is collectively formed on the upper electrode sheet 8, the upper electrode sheet 8
The bus bar 7 provided on the lower electrode sheet 4 is directly connected to the routing circuit 11 on the same sheet, and the bus bar 3 provided on the lower electrode sheet 4 is connected to the routing circuit 11 on the upper electrode sheet 8 via the conductive adhesive 12. (See FIG. 4). The conductive adhesive 12 is applied by a dispenser or the like, and heat treatment is performed after bonding the upper and lower electrode sheets according to the curing conditions.

[0004]

However, since the conductive adhesive 12 and the routing circuit 11 have different thermal shrinkage rates, the connection between the conductive adhesive 12 and the wiring circuit 11 may be stressed during the curing treatment of the conductive adhesive 12 or during an environmental resistance test. In some cases, cracks 14 and the like occur in the routing circuit 11 between the connection portion and the periphery thereof, resulting in poor conduction (see FIG. 5).

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, and to provide a touch panel which does not cause a conduction failure even if a crack or the like occurs in a wiring circuit between a connection portion and the periphery thereof. It is in.

[0006]

In order to achieve the above-mentioned object, the present invention provides a lower electrode sheet having a transparent conductive film and a pair of parallel bus bars formed on a transparent insulating substrate. An upper electrode sheet having a transparent conductive film and a pair of parallel busbars formed on a flexible insulating base material, a spacer interposed between the conductive films, and a direction between the lower electrode sheet busbars and the upper electrode sheet busbars. A wiring circuit that is superposed so that the directions are orthogonal to each other and the peripheral portion thereof is bonded with an adhesive layer, and a wiring circuit that is connected to all bus bars on one of the upper electrode sheet and the lower electrode sheet is provided collectively, and the wiring circuit is provided. In an analog resistive touch panel using a conductive adhesive for connection with the bus bar of the electrode sheet on which the wiring circuit and the wiring circuit of the electrode sheet are not provided, And a configuration in which the connection region between the routing circuits and the bus bar a can turning circuit lower by the conductive adhesive, and the auxiliary conductive films independent of the conductive film at a position overlapping with the adjacent region is provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a touch panel according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing one embodiment of an electrode sheet of a touch panel according to the present invention, and FIG. 2 is a partially enlarged view showing one embodiment of a routing circuit of the touch panel according to the present invention. 1 is an insulating substrate, 2 is a conductive film, 3 is a bus bar, 4 is a lower electrode sheet, 5 is a flexible insulating substrate, 6 is a conductive film, 7 is a bus bar, 8 is an upper electrode sheet, and 11 is a wiring circuit. ,
Reference numeral 12 denotes a conductive adhesive, 13 denotes an auxiliary conductive film, and 14 denotes a crack.

The present invention relates to a touch panel of the analog resistive film type, as shown in FIG. 1, which is under the wiring circuit 11 and overlaps with the connection area between the wiring circuit 11 and the bus bar by the conductive adhesive 12 and the adjacent area. An auxiliary conductive film 13 independent of the conductive film is provided at the location.

The routing circuit 11 includes a lower electrode sheet 4 in which a transparent conductive film 2 and a pair of parallel bus bars 3 are formed on a transparent insulating substrate 1, or a transparent electrode on a transparent flexible insulating substrate 5. The conductive film 6 and the upper electrode sheet 4 on which a pair of parallel bus bars 7 are formed are collectively provided and connected to all the bus bars 3 and 7.

Examples of the insulating substrate 1 include glass plates such as soda glass, borosilicate glass, and tempered glass, engineering plastics such as polycarbonate, polyamide, and polyetherketone, acrylics, polyethylene terephthalate, and polybutylene. A transparent resin plate or a transparent film of terephthalate or the like is used.

As the flexible insulating base material 5, engineering plastics such as polycarbonate, polyamide, and polyetherketone, and transparent films such as acrylic, polyethylene terephthalate, and polybutylene terephthalate are used. In addition, the flexible insulating substrate 5
A hard coat layer may be formed on the surface opposite to the surface on which the conductive film 6 is provided. The hard coat layer includes an inorganic material such as a siloxane-based resin or an organic material such as an acrylic epoxy-based or urethane-based thermosetting resin or an acrylate-based photocurable resin. The thickness of the hard coat layer is suitably about 1 to 7 μm. Further, the flexible insulating base material 5 may be subjected to a non-glare treatment on the surface opposite to the surface on which the conductive film 6 is provided in order to prevent light reflection. For example, the flexible insulating base material 5 and the hard coat layer are processed to have irregularities, and the hard coat layer is mixed with extender pigments or fine particles such as silica and alumina. Further, the flexible insulating base material 5 includes 1
Instead of a single film, a laminate in which a plurality of films are stacked may be used.

The conductive films 2 and 6 include tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide,
Metal oxide films such as indium tin oxide (ITO), composite films mainly containing these metal oxides, gold, silver,
There are metal films such as copper, tin, nickel, aluminum, and palladium. Further, the conductive films 2 and 6 may be formed in multiple layers. Examples of a method for forming the conductive films 2 and 6 include a vacuum deposition method, sputtering, ion plating, and a CVD method. Note that, due to the characteristics of the touch panel, one of the conductive films 2 and 6 provided on the electrode sheet on the side having the routing circuit 11 must not be electrically connected to the routing circuit 11 connected to the bus bar of the other sheet. Therefore, it is formed in a pattern avoiding the routing circuit 11 connected to the bus bar of the other sheet as shown in FIG. On the other hand, when the conductive films 2 and 6 are provided on the side of the electrode sheet that does not have the routing circuit 11, the entire conductive sheet may be solidly formed. As a method of patterning the conductive films 2 and 6, a method of performing an etching process with an acid or the like to remove unnecessary portions is used. Further, a spacer is formed on one of the surfaces of the conductive films 2 and 6. For the spacer, for example, acrylate resin such as melamine acrylate resin, urethane acrylate resin, epoxy acrylate resin, methacryl acrylate resin, acrylate acrylate resin, etc. It can be obtained by forming. Also, a large number of fine dots can be formed by a printing method to form a spacer.

As the bus bars 3 and 7 and the routing circuit 11, a conductive paste such as a metal such as gold, silver, copper, and nickel or carbon is used. Examples of the method for forming the bus bars 3 and 7 include printing methods such as screen printing, offset printing, gravure printing, and flexographic printing, a photoresist method, and a brush coating method.

The conductive adhesive 12 is used to connect the routing circuit 11 provided on one sheet to the bus bar on the other sheet. As the conductive adhesive 12,
An ink in which conductive particles such as silver and nickel are dispersed in an epoxy-based resin or a silicon-based resin is applied using a dispenser or the like.

The auxiliary conductive film 13 is formed independently of the conductive films 2 and 6 in a portion below the routing circuit 11 and overlapping with a connection region between the routing circuit 11 and the bus bar by the conductive adhesive 12 and a region adjacent thereto. I do.

As the auxiliary conductive film 13, a metal oxide film such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, indium tin oxide (ITO), a composite film mainly containing these metal oxides, Money,
There are metal films of silver, copper, tin, nickel, aluminum, palladium, and the like. Further, the auxiliary conductive film 13 may be formed in multiple layers. As a method of forming the auxiliary conductive film 13, a film is formed on the entire surface by vacuum evaporation, sputtering, ion plating, CVD, or the like, and then etching is performed with an acid or the like to remove unnecessary portions. There is a method in which the films 2 and 6 are formed simultaneously with the one provided on the electrode sheet on the side having the routing circuit 11. In addition, if the auxiliary conductive film 13 is formed so as to protrude from the outline of the routing circuit 11 and be partially exposed, the effect of the auxiliary conductive film 13 can be obtained even if the routing circuit 11 is slightly misaligned. Can be fully exhibited without being impaired.

Since the touch panel of the present invention has the auxiliary conductive film 13 as described above, it is supposed that the connection portion between the conductive adhesive 12 and the surrounding area is temporarily set at the time of the curing treatment of the conductive adhesive 12 or the environmental resistance test. Even if a crack or the like occurs in the routing circuit 11 between them, a current flows through the lower auxiliary conductive film 13, so that conduction failure does not occur (see FIG. 2).

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a UV-curable acrylic hard coat is applied by gravure printing on one surface of a flexible insulating substrate made of a roll-shaped polyethylene terephthalate film, and an ITO film is formed on the opposite surface by sputtering. To form an ITO film with a hard coat. After the roll film is cut into a sheet, an etching resist is applied in a pattern on the ITO film by screen printing, and an unnecessary portion of the ITO film is removed with hydrochloric acid to form a rectangular conductive film. At this time, the vicinity of the two opposing sides of the conductive film is left in an island shape without being removed by etching, and this is used as an auxiliary conductive film. After the etching, the resist is removed with an alkali, and a bus bar is formed on the remaining two sides of the conductive film by screen printing using silver ink. Further, a drawing circuit is formed with silver ink by screen printing to obtain an upper electrode sheet.

On the other hand, an ITO film is formed by vacuum evaporation on one surface of an insulating substrate made of a soda glass plate, and fine dots are formed on the ITO film by a photo process using an epoxy acrylate-based photocurable resin. A spacer is obtained, and a lower electrode sheet having a pair of parallel bus bars formed by screen printing using silver ink is obtained.

Next, a double-sided tape is punched on the surface of the upper electrode sheet on which the conductive film is formed, by punching out a portion corresponding to the panel visible area, a portion for applying the auxiliary conductive film and a conductive adhesive on the routing circuit. At the same time, a conductive adhesive in which a silver filler is dispersed in silicon is applied to a portion of the routing circuit where the double-sided tape has come off using a dispenser.

Next, the upper electrode sheet and the lower electrode sheet are bonded together so that the surfaces on which the conductive films are formed face each other, and the direction between the bus bars of the lower electrode sheet and the direction between the bus bars of the upper electrode sheet are orthogonal to each other. .

After bonding, the conductive adhesive was cured in an oven at 130 ° C. to obtain a touch panel.

The touch panel thus obtained is
Even if a crack or the like occurs in the routing circuit between the connection portion with the conductive adhesive and its surroundings during the curing treatment of the conductive adhesive, conduction failure does not occur via the lower auxiliary conductive film,
Very high in reliability.

[0025]

The touch panel of the present invention has the above-described configuration and operation, and has the following effects.

That is, in the touch panel of the present invention, an auxiliary conductive film which is independent of the conductive film is provided in a lower layer of the routing circuit and in a portion overlapping with a connection region between the routing circuit and the bus bar by the conductive adhesive and the adjacent region. Therefore, even if a crack or the like occurs in the routing circuit between the connection part with the conductive adhesive and its surroundings during the curing treatment of the conductive adhesive or the environmental resistance test, the lower auxiliary conductive film is formed. A current flows through the circuit, and no conduction failure occurs. Therefore,
Compared with conventional touch panels, a very high reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an electrode sheet of a touch panel according to the present invention.

FIG. 2 is a partially enlarged view showing an embodiment of a routing circuit for a touch panel according to the present invention.

FIG. 3 is a view showing a conventional analog resistive film type touch panel.

FIG. 4 is a partially enlarged view showing one embodiment of a conventional routing circuit of a touch panel.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 insulating base material 2 conductive film 3 bus bar 4 lower electrode sheet 5 flexible insulating base material 6 conductive film 7 bus bar 8 upper electrode sheet 9 spacer 10 adhesive layer 11 wiring circuit 12 conductive adhesive 13 auxiliary conductive film 14 crack

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[Procedure amendment]

[Submission date] June 18, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an electrode sheet of a touch panel according to the present invention.

FIG. 2 is a partially enlarged view showing an embodiment of a routing circuit for a touch panel according to the present invention.

FIG. 3 is a view showing a conventional analog resistive film type touch panel.

FIG. 4 is a cross-sectional view showing one embodiment of a peripheral portion of a conventional touch panel.

FIG. 5 is a partially enlarged view showing one embodiment of a conventional routing circuit of a touch panel.

[Description of Signs] 1 insulating base material 2 conductive film 3 bus bar 4 lower electrode sheet 5 flexible insulating base material 6 conductive film 7 bus bar 8 upper electrode sheet 9 spacer 10 adhesive layer 11 wiring circuit 12 conductive adhesive 13 auxiliary Conductive film 14 crack

Claims (1)

[Claims] 1. A lower electrode sheet having a transparent conductive substrate and a pair of parallel bus bars formed on a transparent insulating substrate; and a transparent conductive film and a pair of parallel electrodes formed on a transparent flexible insulating substrate. The upper electrode sheet on which the bus bar is formed is overlapped with a spacer between the conductive films so that the direction between the bus bars on the lower electrode sheet and the direction between the bus bars on the upper electrode sheet are orthogonal to each other, and the peripheral portion is bonded with an adhesive layer. A wiring circuit connected to all the bus bars is provided collectively on one of the upper electrode sheet and the lower electrode sheet, and the wiring circuit and the wiring circuit on the side where the wiring circuit is not provided are provided on the side where the wiring circuit is provided. In an analog resistive touch panel that uses a conductive adhesive to connect an electrode sheet to a bus bar, the wiring is a lower layer of a wiring circuit, and the wiring is a conductive adhesive. A touch panel, wherein an auxiliary conductive film independent of a conductive film is provided in a portion overlapping a connection region between a road and a bus bar and a region adjacent thereto.