JP2005078491A - Apparatus of transparent touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus of a transparent touch panel, which comprises a plurality of electrodes on the four sides of a substrate, a means for detecting a position on both horizontal and vertical axes, and a small outside space surrounding a touch operational area with a high sensitivity to a touch operation, as well as is provided with a conductive film and a leading circuit line, each of them having a stabled resistance value. <P>SOLUTION: The apparatus of the transparent touch panel, which comprises electrodes of 12, 23, 34, and 41 positioned on the four sides of a surrounding portion of a conductive film 51, and a circuit wired from an intersecting point with the electrodes, features a binding activity, which implies a metal segment 75 and the electrodes 12, 23, 34, and 41 are bound with a conductive binding agent 80 after the circuit wire 85 is fixed at the metal segment 75 using solder 82. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a touch panel device that is arranged on a display device such as a CRT or a liquid crystal panel, and that is input with a finger, a pen, or the like. The present invention relates to a transparent touch panel device.

A transparent touch panel device that has electrodes on four sides of one substrate, the opposing electrodes as one axis, and a position detection function in two vertical and horizontal directions is obtained by touching the substrate with a finger, a pen, or a conductive film. This is a transparent touch panel device that detects the contact position. This transparent touch panel device has a single substrate structure when touching the substrate with a finger or pen. Moreover, when touching with a conductive film, it has a two-sheet structure in which a conductive film having substantially the same shape as the electrode substrate is provided with a gap with a dot spacer. In the case of touching with a conductive film, there is an advantage that the resistance value of the conductive film for sensing does not affect the accuracy even if there is variation due to position or changes over time, and that it has a long life.
However, in any case, since the electrodes are formed on the four sides of the substrate, an error occurs between the input position and the detection position, and the error increases as the distance from the center portion increases. The equipotential line at the detection position is curved with respect to the electrode.

  FIG. 3 is an explanatory diagram of electrodes, detection areas, and bending distortion areas of the touch panel device. In FIG. 3, the intersections of the electrodes 12, 23, 34, and 41 are the power supply terminals 1, 2, 3, and 4, and the area surrounded by the electrodes 12, 23, 34, and 41 is a surface on which touch input is performed. The area detected by switching the voltage between the vertical axis and the horizontal axis is a detection area 50 surrounded by a parabola. Therefore, in order to correct the bending distortion 112, 123, 134, 141, the input position is obtained by calculating with an approximate expression or by comparing with an actual measurement value. However, when the bending distortion areas 212, 223, 234, and 241 are wide, high accuracy is not obtained even if calculation is performed using an approximate expression or comparison with actual measurement values. In order to improve the accuracy, it is necessary to reduce the bending distortion areas 212, 223, 234, and 241 around the touch panel.

  As a countermeasure, there is a method of providing a large number of electrodes. (For example, refer to Patent Document 1.) Further, there is a method in which a lead wiring is provided from the center point of each side, the voltage value is monitored, and position correction is performed. (For example, refer to Patent Document 2.) In addition to the correspondence with the electrode pattern, a simple electrode can be configured only when necessary by arranging a diode or the like without forming electrodes on the four sides. There is also. There is a method of using a calculation formula to determine the resistance value of the electrode. (For example, refer to Patent Document 3.)

FIG. 4 is an explanatory diagram of an example of a conventional transparent touch panel, and routing circuits 61, 62, 63, 64 are led to the flexible connector 60 from the intersections of the electrodes 12, 23, 34, 41. For the connection between the board routing circuits 61, 62, 63, 64 and the flexible connector 60, a method of fixing by thermocompression bonding using anisotropic conductive ink is often employed.
The lower the resistance value of the routing circuit, the higher the detection resolution. This is because the voltage drop in the routing circuit among the externally applied voltages does not work effectively for position detection. In order to reduce the resistance value of the routing circuit, the width must be widened, and contact resistance is generated at the connecting portion, and it is difficult to make it 1Ω or less. In addition, there are problems such as a temporal change in the resistance value of the routing circuit to the end of the substrate, an abnormal resistance value due to poor contact of the connection portion, and peeling of the flexible connector due to a severe use environment.

As another routing circuit connection method, there is a method in which an electrode is made of silver ink for high-temperature firing and a wire is soldered to the intersection of the electrodes. In this connection method, it is necessary to fire the silver electrode at a high temperature of about several hundred degrees Celsius (for example, 400 degrees Celsius) after the electrodes are formed, and the conductive film is also fired at the same time, so the resistance value of the conductive film is very high. And there is a problem that causes variation. Also, there is a problem that only the substrate material that can withstand high temperatures is used.
JP 61-182127 A JP-A-10-83251 JP 2002-99389 A

The problem to be solved is to detect and stabilize the resistance value of the conductive film and the lead line in a transparent touch panel device having electrodes on four sides of one substrate and having a vertical and horizontal biaxial position detection function. It is an object of the present invention to provide a transparent touch panel device that is highly accurate and reduces the space around the operation area.

In order to achieve the above object, the transparent touch panel device of the invention of claim 1 has a conductive film on the surface of the substrate, and wire wiring from an intersection of four electrodes arranged in a rectangular shape on the outer periphery of the conductive film. In the transparent touch panel device, the wire is fixed to a metal piece, and the metal piece is bonded to the intersection of the electrodes with a conductive adhesive.

A transparent touch panel device according to a second aspect of the present invention is the touch panel device according to the first aspect, wherein the substrate is made of a plastic substrate.

A transparent touch panel device according to a third aspect of the present invention is the touch panel device according to the first or second aspect, wherein the resistance values of the electrodes on the four sides are 30Ω to 500Ω, respectively.

The transparent touch panel device according to a fourth aspect of the present invention is the touch panel device according to any one of the first to third aspects, wherein the width of the electrodes on the four sides is 2 mm or less.

The transparent touch panel device according to a fifth aspect of the present invention is the touch panel device according to any one of the first to fourth aspects, wherein the electrodes on the four sides are each linear.

A transparent touch panel device according to a sixth aspect of the present invention is the touch panel device according to any one of the first to fifth aspects, wherein a value obtained by dividing the area surrounded by the electrodes on the four sides by the area of the substrate is 0.8. It is characterized by a larger value.

A transparent touch panel device according to a seventh aspect of the present invention is the touch panel device according to any one of the first to sixth aspects, wherein the resistance value of the routing of the two wires at both ends in the routing of the electrode and the wires from both ends thereof. The values obtained by dividing the resistance by the resistance value of the electrodes are all smaller than 0.1.

As described above, according to the present invention, in the transparent touch panel device, the voltage drop of the routing circuit is small, the resistance value of the routing circuit is stabilized over time, and the space outside the operation area is reduced. .

  Embodiments of the present invention will be described below. Since each drawing is drawn so that the configuration is easy to understand, it is not an actual size ratio but is partially enlarged or reduced.

(Embodiment 1) FIG. 1 is an explanatory diagram of wire connection in a touch panel device of the present invention. The substrate 30 has a conductive film 51, and the electrodes 12, 23, 34, and 41 are disposed on the conductive film 51. A metal piece 75 in which a wire 85 is fixed with a solder 82 is bonded to the intersection of the electrodes 12, 23, 34, 41 with a conductive adhesive 80. The wire 85 may be covered except for the soldered portion.

Substrate A glass substrate or a plastic substrate is used as the substrate. As the glass substrate, soda glass, alkali-free glass, borosilicate glass, quartz glass or the like is used, and the thickness of the glass substrate is about 0.5 to 5 mm.
Plastic substrates include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polyethersulfone (PES), polyetheretherketone (PEEK), polycarbonate (PC), polypropylene (PP), polyamide A film made of (PA), polyacrylic (PAC), norbornene-based thermoplastic transparent resin, or a laminate of these films is used. The plastic substrate may be laminated with a support to reinforce and improve durability. The support is made of a polycarbonate resin substrate, an acrylic resin substrate, a polyolefin resin substrate, glass, etc., and the thickness of the support is usually 0.5 to 5 mm, and the shape is often flat, Some of them are convex.

Conductive film As the material for forming the conductive film of the substrate, a tin oxide film and an ITO (Indium Tin Oxide / Indium Tin Oxide) film are often used, and copper, aluminum, nickel, chromium, and the like are also conceivable. Moreover, these alloys may be sufficient and a different forming material may overlap and be formed. Further, before forming the transparent conductive film, an undercoat layer may be provided for improving transparency and adhesion. As a method for forming a transparent conductive film, a PVD method such as a sputtering method, a vacuum deposition method, or an ion plating method, or a CVD method, a coating method, a printing method, or the like is appropriately used depending on the type of the conductive film to be formed. Selected. The resistance value of the conductive film of the substrate is usually about 300Ω / □ to 3000Ω / □.

Patterning of conductive film Next, the conductive film of the substrate is patterned. FIG. 2 is an explanatory diagram of the touch panel device of the present invention, and the conductive film is removed by etching outside the electrode portions 12, 23, 34, and 41. FIG. For the part where the conductive film is to be left, a desired pattern-shaped mask is formed on the conductive film surface of the substrate, and after that, etching is performed with an acid solution to remove only unnecessary portions of the conductive film. The patterned mask is removed by dissolution or the like. There is also a method of removing the conductive film in a linear or planar shape with a laser without performing etching with an acid solution.

Electrode printing Next, electrode printing of the substrate is performed. The electrode of the substrate is formed by screen printing, but the formation method is not particularly limited. Generally, silver paste, copper paste, silver and carbon, or the like is used as the electrode material, but other materials may be selected as long as the volume resistance is kept constant and the material is stable. Regarding the selection of the conductive material, it is necessary to determine the resistance value of the electrode on each side in advance and select the volume resistance value of the conductive material. As shown in FIG. 2, the power supply terminals 91, 92, 93, and 94 may be extended to the corners of the substrate at the intersections of the electrodes.

  When the resistance value of the conductive film of the substrate is about 300Ω / □ to 3000Ω / □, the resistance value of the electrode is preferably 30Ω to 500Ω Ohm, more preferably 60Ω to 200Ω Ohm, more preferably 80Ω to 100Ω, and bending distortion. It is optimal within 1%. As for the resistance value balance of each side, since the bending distortion exceeds 2% when the error exceeds 20%, it is desirable that the resistance value of each side is substantially the same. When the touch panel is rectangular, changing the electrode widths on the long side and the short side to have substantially the same resistance value makes it easier to control when switching between the two axes.

The specific resistivity of the electrode material is preferably 1.0 × 10 ⁻⁴ [Ω · cm] to 1.0 × 10 ⁻³ [Ω · cm]. If it is lower than 1.0 × 10 ⁻⁴ [Ω · cm], it is not suitable for the resistance value. If it is higher than 1.0 × 10 ⁻³ [Ω · cm], the resistance value is not stable.

Connection of wire wiring First, the wire is fixed to a metal piece, and the fixing method is generally soldering. The metal piece to which the wire is fixed is adhered to the intersection of the electrodes on the four sides with a conductive adhesive. As the conductive adhesive, a two-component epoxy conductive adhesive (product number 3380) manufactured by Three Bond Co., Ltd. can be used. The wire is taped around the substrate and connected to the control unit outside the substrate.

As a substrate, a 2000 Ω / □ tin oxide film was formed by sputtering on soda glass having a size of 250 mm * 328 mm and a thickness of 2.5 mm.
Next, an electrode was produced by screen printing. As the conductive material, a specific resistance of 5.0 × 10 ⁻⁴ [Ω · cm] was obtained by adding carbon powder, vinyl resin, phenol resin, silica filler, and the like to silver powder.
The electrode shape of the printed circuit board is
The short side is 236mm * 1.41mm,
The long side was 314 mm * 1.85 mm.
As shown in FIG. 2, the wires 85, 85, 85, 85 bonded by the power supply terminals 91, 92, 93, 94 are connected to the controller 70. The value obtained by dividing the area surrounded by the electrodes by the substrate area was 0.88, and the resistance values of the four electrodes were approximately 90Ω and the variation was within 10%.

The wires used were those manufactured by Junko Co., Ltd. (Junflon electric wire with insulator material FEP, model number AF04A030). The metal piece was made of copper, had a thickness of 0.15 mm, an adhesion area of 5 mm square, and smaller than the area of the power supply terminals 91, 92, 93 and 94. The two-component epoxy conductive adhesive (product number 3380) manufactured by Three Bond Co., Ltd. was adhered and fixed to the power supply terminals 91, 92, 93, 94 and cured at 80 ° C. for 2 hours.

The resistance of the wire wiring was 500 mm in length and less than 1Ω. Since the resistance value of the four electrodes was approximately 90Ω, the total resistance value of the wiring of the two wires at both ends was divided by the resistance value of the electrode in the wiring of the electrode and the wires from both ends thereof. The value was about 0.02.
The wire was taped around the substrate, connected to a controller outside the substrate, contacted with a pen, and the measured bending distortion was within 2%.

For confirmation of the conventional method, the electrodes were produced in the same manner as in Example 1, and then the routing circuits 61, 62, 63, 64 were produced with silver ink to the edge of the substrate as shown in FIG. The routing circuits 61 and 64 had a length of about 44.5 mm, a width of about 3.5 mm, and a resistance value of about 5Ω. The routing circuits 62 and 63 had a length of about 11.5 mm, a width of about 1.0 mm, and a resistance value of about 5Ω. Since the resistance value of the four electrodes was approximately 90Ω, when the silver ink was routed from the electrode and both ends of the electrode, the total resistance value of the two silver ink routes was calculated as the resistance value of the electrode. The divided value was about 0.1.

  Applicable to transparent touch panel.

Explanatory drawing of the wire connection in the touchscreen apparatus of this invention. Explanatory drawing of the touchscreen apparatus of this invention. Explanatory drawing of the electrode of a touchscreen apparatus, a detection area, and a curvature distortion area. Explanatory drawing of an example of the conventional transparent touch panel. Explanatory drawing of an example of the conventional routing circuit.

Explanation of symbols

1, 2, 3, 4 Feeding terminals 12, 23, 34, 41 Electrode 30 Substrate 50 Detection area 51 Conductive film 60 Flexible connectors 61, 62, 63, 64 Routing circuit 70 Controller 75 Metal strip 80 Conductive adhesive 82 Solder 85 Wire 91, 92, 93, 94 Power supply terminal 100 Transparent tachi panel device 112, 123, 134, 141 Curve distortion 212, 223, 234, 241 Curve distortion area

Claims (7)

  In a transparent touch panel device having a conductive film on a surface of a substrate and wired by wires from the intersection of four electrodes arranged in a rectangle on the outer periphery of the conductive film, the wire is fixed to a metal piece, and the metal piece A touch panel device characterized in that is bonded to the intersection of the electrodes with a conductive adhesive. The touch panel device according to claim 1, wherein the substrate is made of a plastic substrate.   The touch panel device according to claim 1, wherein the resistance values of the electrodes on the four sides are 30 Ω to 500 Ω, respectively.   The touch panel device according to claim 1, wherein a width of the electrodes on the four sides is 2 mm or less.   The touch panel device according to claim 1, wherein the electrodes on the four sides are each linear.   The touch panel device according to claim 1, wherein a value obtained by dividing an area surrounded by the electrodes on the four sides by an area of the substrate is a value larger than 0.8.   In the routing of the electrode and the wires from both ends thereof, all the values obtained by dividing the resistance value of the routing of the two wires at both ends by the resistance value of the electrode are smaller than 0.1. The touch panel device according to claim 1.

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