JP5262666B2 - Capacitive touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitance touch panel with high reliability in S/N ratio, which is effective in allowing the pattern structure of a sensor to be inconspicuous when viewed from a front surface side. <P>SOLUTION: A pattern made of a transparent conductive film is formed on the upper surface of a transparent substrate directly or via a foundation layer. A protective sheet material is adhered via an adhesive layer so as to cover the pattern. In the pattern, a plurality of first and second electrodes are alternately formed in a matrix shape on the same surface, where the plurality of first electrodes arrayed in a row direction are connected in the row direction by a first conductive part, the plurality of second electrodes arrayed in a column direction are connected in a column direction by a second conductive part, and the intersection parts of the respective first and second conductive parts are arranged via intermediate insulating layers. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a capacitive touch panel, and particularly relates to a panel structure effective for making a pattern portion formed of a transparent conductive film inconspicuous.

For example, a touch panel that performs a touch operation with a finger or the like and inputs a touch position while visually recognizing a display image on a liquid crystal panel or the like is widely used.
In recent years, a capacitive touch panel that detects a change in capacitance depending on a position touched by a finger on a display panel such as a mobile phone is becoming widespread as this touch panel.
In a conventional general capacitive touch panel, an insulating layer is formed to cover the entire surface of a capacitive induction layer composed of a first electrode pattern, and a second electrode pattern arranged in a matrix on the insulating layer. This is disadvantageous in reducing the thickness of the panel.
In order to make the electrode pattern inconspicuous from the operation surface, it is conceivable to use a conductive film material having a high visible light transmittance. However, a conductive film material having a transmittance of 90% or more has an electric resistance of about 300Ω / □. It is relatively high and noise is likely to occur in the outer peripheral area of the electrode pattern.
The applicant of the present application has proposed a technique for forming a shield layer in the outer peripheral region of the electrode pattern as a noise countermeasure (Patent Document 3).
On the other hand, the present application has studied that the high S / N ratio can be ensured without forming a shield layer in the outer peripheral area of the electrode pattern, and the electrode pattern becomes inconspicuous from the operation surface, leading to the present invention. It was.
In Patent Documents 1 and 2, a row-direction electrode and a column-direction electrode formed in a matrix are formed on the same plane, and a conduction portion that connects the electrodes in the row direction and a conduction portion that connects the electrodes in the column direction, The technique which provided the insulating layer only in the crossing part of this is disclosed.
However, in the panel structure disclosed in the publication, there is a problem that the bridge structure portion where the conductive portions intersect is conspicuously visually recognized.
In addition, there is a problem that defects such as cracks are likely to occur in the conductive portion when the conductive portion is formed to cross the intersection.

Utility Model Registration No. 3144241 Utility Model Registration No. 3134925 Japanese Patent Application No. 2008-007755

  In view of the above technical problem, an object of the present invention is to provide a capacitive touch panel that is effective in making the pattern structure of the sensor portion inconspicuous from the surface side and has high S / N ratio reliability.

The capacitive touch panel according to the present invention forms a pattern portion made of a transparent conductive film directly on the upper surface of a transparent substrate or through an underlayer, and an optically transparent adhesive layer so as to cover the pattern portion. The protective sheet material is pasted, and the pattern portion has a plurality of first electrodes and second electrodes formed alternately and in a matrix on the same plane, and a plurality of first electrodes arranged in the row direction. Are connected in the row direction at the first conduction part, and the plurality of second electrodes arranged in the column direction are connected in the column direction at the second conduction part, and the first conduction part includes the plurality of first electrodes and Formed in a step prior to the step of forming a plurality of second electrodes, and at least a part of the first electrodes on both sides connected by the first conductive portion ride on both ends of the first conductive portion, respectively. Yes formed, the intersection of the first conductive portion and the second conductive part is the dielectric constant 1 20. An intermediate insulating layer made of an organic thin film using a photoresist material having a thickness of 0.1 to 10 μm is interposed, and the conductive portion made of a transparent conductive film crosses the upper surface after film formation. The outer shape of the portion is generally trapezoidal, and the angle θ between both ends of the upper base is 120 ° or more.
Here, the pressure-sensitive adhesive layer refers to an optically transparent pressure-sensitive adhesive layer such as optical glue, and acrylic optical glue having high transparency is preferable, but silicon-based pressure-sensitive adhesive may also be used.
The protective sheet material includes a display panel such as a decorative board and a display film.

In addition, the present invention aims to arrange the first electrode and the second electrode in a matrix shape, and the first conduction part and the second conduction part intersect each other . In particular, the first conduction part is on the lower side. And the second conductive portion is located above the second conductive portion.
The electrode and the conductive part are formed of a transparent conductive film. As the transparent conductive film, various metal oxides such as ITO (indium tin oxide), zinc oxide, indium oxide, antimony-added tin oxide, and aluminum-added zinc oxide are used. Although it can be adopted, it is preferable to use a low-resistance ITO film.

Here, the intermediate insulating layer is preferably an organic thin film having a dielectric constant of 1 to 20 and a thickness of 0.1 to 10 μm, and more preferably a dielectric constant of 3 to 5 and a thickness of 1 to 5 μm.
Furthermore, after the film is formed, the intermediate insulating layer has a trapezoidal outer shape where the conductive portion made of the transparent conductive film crosses the upper surface, and the angle θ between both ends of the upper base is 120 ° or more. Is preferred.

In the present invention, since a protective sheet is stuck on a matrix-like electrode pattern made of a transparent conductive film via an adhesive layer such as optical glue, the bridge structure at the intersection becomes inconspicuous.
Furthermore, by reducing the range of the intermediate dielectric layer with a high dielectric constant, making it an organic thin film, and making its cross-sectional shape trapezoidal, it prevents cracks and cracks from forming on the transparent conductive film formed on it. The parasitic capacitance is reduced and the S / N ratio is improved.
Conventionally, when an insulating layer is formed of an organic thin film, the angle of the upper surface corner is 90 ° in order to increase the resolution.
However, when the angle of the upper surface of the insulating layer is 90 °, it has been clarified through experiments that a conductive portion that intersects the upper surface is likely to crack, and the present invention makes the insulating layer of the organic thin film substantially trapezoidal. The crack of the upper conduction part was prevented.
In the present invention, the visible light transmittance is slightly low because the bridge crossing and the electrode pattern are inconspicuous, but a high S / N ratio is obtained even when a transparent conductive film having a low resistance value of 70 to 100Ω / □ is employed. Can be ensured, and it is no longer necessary to form a noise countermeasure shield layer in the outer peripheral area of the electrode pattern.

The capacitive touch panel according to the present invention will be described with reference to the drawings.
FIG. 1A shows an explanatory diagram of the touch panel 10 viewed from the operation surface side, and FIG. 1B shows an enlarged perspective view.
FIG. 5 is an external view of the touch panel 10.
All the figures are schematically shown for easy understanding, and are partially enlarged or reduced in comparison with actual figures.
The pattern part is also shown schematically, although it is virtually invisible.
The touch panel 10 has a sensor part S on one side of a transparent substrate 11 such as a glass substrate as shown in a sectional view in FIG. 3, and the sensor part S is a first electrode (X Electrode) 12, a second electrode (Y electrode) 14, and a first conduction part (X conduction part) 13, and a second conduction part 15 made of a transparent conductive film so as to cross the first conduction part 13 Between the first conducting part 13 and the second conducting part 15, an intermediate insulating layer 16 made of an insulating organic thin film is provided.
In the first electrode 12, the first electrodes 12 adjacent to each other in the panel horizontal direction (X direction) are connected to each other by the first conduction part 13.
As a result, a row is formed by the first electrode 12 and the first conductive portion 13, and a plurality of rows are formed as necessary to form a first electrode pattern.
In the second electrode 14, the second electrodes 14 adjacent to each other in the panel vertical direction (Y direction) are connected by the second conductive portion 15.
As a result, a column is formed by the Y-th electrode 14 and the second conductive portion 15, and a plurality of columns are formed as necessary to form a second electrode pattern.
The first electrode 12 and the second electrode 14 are arranged in a matrix in which the panels are alternately arranged in directions orthogonal to each other.
Further, a predetermined gap portion d is provided between the first electrode 12 and the second electrode 14 so as to store a predetermined capacity of charge.
The first conductive portion 13 and the second conductive portion 15 intersect with the intermediate insulating layer 16 therebetween.
The intermediate insulating layer 16 is generally sized so as not to overlap the first electrode 12 and the second electrode 14.

FIG. 2 is an explanatory diagram of an example of a method for forming the first electrode 12, the first conduction part 13, the second electrode 14, the second conduction part 15, and the intermediate insulating layer 16.
First, as shown in FIG. 2A, the first conduction part 13 is formed on the transparent substrate 11.
Next, as shown in FIG. 2B, an intermediate insulating layer 16 is formed on the transparent substrate 11 with a photoresist or the like so as to cover a predetermined range intersecting with the second conductive portion 15 in the first conductive portion 13.
Then, as shown in FIG. 2C, the first electrode 12, the second electrode 14, and the second conduction portion 15 are formed in a lump.
FIG. 3A shows a cross-sectional view taken along the line AA, and FIG. 3B shows a cross-sectional view taken along the line BB.
Thus, when the 1st conduction | electrical_connection part 13 is formed in the process before the process of forming the several 1st electrode 12 and the 2nd electrode 14 on the transparent substrate 11, after forming the 1st electrode 12 grade | etc., FIG. As shown to a), at least one part of the 1st electrode 12 connected with the both sides of the 1st conduction | electrical_connection part 13 rides and is formed.

3A is a schematic cross-sectional view cut in the row direction, and FIG. 3B is a cross-sectional schematic view cut in the column direction.
In this embodiment, the sensor portion S is directly formed on a transparent substrate such as glass. However, the transmittance or reflectance between the electrode pattern portion formed of the transparent conductive film and the other non-pattern portion. May be formed on a transparent substrate, and the sensor unit S may be formed thereon.
As the underlayer, a conventional two-layer structure consisting of a low refractive index layer on the transparent conductive film side with a relatively low optical refractive index and a high refractive index layer with a higher refractive index is used. it can.
For example, silicon oxide can be used as the low refractive index layer, and silicon tin oxide can be used as the high refractive index layer.
When a film for optically adjusting the light emitted from the liquid crystal screen disposed on the bottom surface side of the transparent substrate is used for the base layer, the structure of the first electrode, the second electrode and the intermediate insulating layer of the present invention, A uniform optical effect is given to the sensor unit.

As shown in FIG. 3B, when the second conductive portion of the Y electrode and the Y electrode is formed so as to cross the first conductive portion 13 in which the X electrode and the X electrode are conductively connected, It is necessary to form the intermediate insulating layer 16 between the conducting part and the second conducting part.
In this case, if the angle of the upper surface corner portion θ of the intermediate insulating layer is close to 90 °, cracks and cracks may occur in the corner portion 15c of the second conductive portion 15 when the second conductive portion 15 is formed of an ITO film. Became clear.
Therefore, when forming the organic thin film, the outer shape was made trapezoidal, and the film was formed so that the angle θ at both ends of the upper base was 120 ° or more.
Thereby, it was possible to suppress the occurrence of cracks in the conduction part.
It has also been found that the organic thin film is preferably made of a photoresist material and has a dielectric constant of 1 to 20 and a thickness of 0.1 to 10 μm.

By insulating only the intersection of the first conductive portion 13 and the second conductive portion 15 with the intermediate insulating layer 16 made of an organic thin film, and forming the other pattern portion with an ITO film, the overall parasitic capacitance is reduced. It was possible to reduce the S / N ratio.
However, when viewed from the surface, the crossing bridge portion was visually recognized, and it was a little worrisome that the organic thin film had a slightly yellowish tint.
Therefore, as shown in FIG. 3, when the protective sheet 22 is pasted through the adhesive layer 21 made of optical glue so as to cover the sensor portion S, the pattern portion including the crossed bridge portion is conspicuous from the operation surface. lost.
Here, the protective sheet may be plate-shaped or film-shaped, and becomes a decorative plate.

FIG. 4 shows another production example as a reference example .
The explanatory view of another method of forming the 1st electrode 12a, the 1st conduction part 13a, the 2nd electrode 14a, the 2nd conduction part 15a, and the middle insulating layer 16b is shown.
First, as shown in FIG. 4A, the first electrode 12a, the second electrode 14a, and the second conductive portion 15a are formed on the transparent substrate 11 at once.
Next, as shown in FIG. 4B, an intermediate insulating layer 16a that covers the first electrode 12a, the second electrode 14a, and the second conductive portion 15a is formed, and as shown in FIG. In the layer 16a, a hole 16c is formed in the intermediate insulating layer 16a in a predetermined range and removed in order to connect the first electrodes 12a to each other by the first conductive portion 13a.
And after forming the 1st conduction | electrical_connection part 13a as shown in FIG.4 (d), as shown in FIG.5 (e), the intermediate | middle insulating layer 16b is provided between the 1st conduction | electrical_connection part 13a and the 2nd conduction | electrical_connection part 15a. The intermediate insulating layer located outside the vicinity of the intersection 17 between the first conductive portion 13a and the second conductive portion 15a is removed.

(A) shows explanatory drawing of the touch panel seen from the operation surface side, (b) shows an enlarged perspective view. Explanatory drawing of the method of forming a 1st electrode, a 1st conduction | electrical_connection part, a 2nd electrode, a 2nd conduction | electrical_connection part, and an intermediate | middle insulating layer is shown. (A) shows an AA line sectional view, and (b) shows a BB line sectional view. Explanatory drawing of another method of forming a 1st electrode, a 1st conduction | electrical_connection part, a 2nd electrode, a 2nd conduction | electrical_connection part, and an intermediate | middle insulating layer is shown. The external view of a touch panel is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Capacitive touch panel 11 Transparent substrate 12, 12a 1st electrode 13, 13a 1st conduction | electrical_connection part 14, 14a 2nd electrode 15, 15a 2nd conduction | electrical_connection part 16, 16a, 16b Intermediate insulation layer 16c Hole 17 of an intermediate insulation layer Intersection 21 Adhesive layer 22 Protective sheet d Gap (non-pattern part)
S Sensor part

Claims (2)

Form a pattern portion made of a transparent conductive film directly or through an underlayer on the upper surface of the transparent substrate,
A protective sheet material is pasted through an optically transparent adhesive layer so as to cover the pattern part,
The pattern part has a plurality of first electrodes and second electrodes formed alternately and in a matrix on the same plane,
The plurality of first electrodes arranged in the row direction are connected in the row direction at the first conduction part,
The plurality of second electrodes arranged in the column direction are connected in the column direction at the second conduction portion,
The first conducting portion is formed in a step prior to the step of forming the plurality of first electrodes and the plurality of second electrodes, and at least a part of the first electrodes on both sides connected by the first conducting portion is , Each formed on both ends of the first conductive portion,
The intersection between the first conducting portion and the second conducting portion is through an intermediate insulating layer made of an organic thin film using a photoresist material having a dielectric constant of 1 to 20 and a thickness of 0.1 to 10 μm,
After the film formation, the intermediate insulating layer has a trapezoidal outer shape at the portion where the conductive portion made of the transparent conductive film crosses the upper surface, and the angle θ between both ends of the upper base is 120 ° or more. A capacitive touch panel characterized by that. 2. The capacitive touch panel according to claim 1, wherein the optically transparent adhesive layer is an optical glue or a silicon adhesive.

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