JP6344075B2 - Capacitive touch panel - Google Patents

Description

  The present invention relates to a capacitive touch panel, and relates to a capacitive touch panel that improves the adhesion between a metal electrode and a film substrate and does not cause electrode disconnection or abnormal capacitance.

  Recently, various touch panels have been developed and put into practical use as mobile information terminals using finger input or pen input. The touch panel has an advantage that it can be easily input with a finger or an ordinary pen without using a special pen, and has a relatively simple structure and a low price. Various types of touch panels have been proposed. Among them, a resistive film type and a capacitance type are mainly used.

  The capacitive touch panel has a structure in which a specific electrode pattern is formed, a change in capacitance value between electrodes is detected, and a pressed position is specified. One method of this capacitance type is to pattern two electrodes and convert a weak current at the pressed position into a voltage by a controller to detect the voltage. Therefore, the conductive film or conductive sheet used for the capacitive touch panel is required to have a low surface resistance value and high transparency.

  FIG. 3 shows an example of the configuration of the capacitive touch panel. A large number of fine metal wires 2 are arranged in parallel on both surfaces of the transparent substrate 1 so that the fine metal wires 2 intersect each other vertically and horizontally in a plan view. It is a capacitive touch panel in which the array is formed.

  FIG. 4 shows two transparent composite substrates formed by arranging many conductive metal wires 2 in parallel in one direction on the surface of one surface of the transparent substrate 1, and the surfaces on which the metal wires 2 are arranged are mutually connected. This is a capacitive touch panel configured to overlap each other with an insulating adhesive 5 so as to face each other and the arrangement direction of the fine metal wires 2 is orthogonal (Patent Document 1).

  In a capacitive touch panel in which a metal wiring pattern is provided on a transparent substrate, a metal wiring pattern is generally formed by a printing method, a photolithography method, or the like.

  Unlike a touch panel using a transparent conductive film, a touch panel using metal wiring is inferior in view of visibility, so that it is essential to make the metal wiring thin. For this purpose, the photolithography method is most suitable.

  The metal film used for the photolithographic method directly forms a metal film having a thickness of micron or submicron by vapor deposition, sputtering, or plating on a transparent substrate such as PET.

  In order to obtain tensile strength, the transparent base material is stretched and generally has excellent transparency, and therefore a biaxially stretched PET film is used. In such a biaxially stretched film, there are many surface scratches with a length of several tens of μm or more and a depth of several μm, and when a metal film is formed on the PET film, This causes a problem that the surface of the metal film tears starting from surface scratches.

  Such a fissure of the metal film has a length of several tens to several hundreds of μm and a width of several μm, and if the fissure exists in the wiring part of the metal film touch sensor, it becomes a disconnection or an abnormal capacitance value. There is a problem that the touch panel becomes defective.

JP 2011-28699 A

  Provided is a capacitive touch panel using fine metal wiring that does not cause disconnection of metal wiring or abnormal capacitance value due to disconnection even when a biaxially stretched film having many surface scratches is used as a transparent substrate.

As means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that a large number of fine metal wires are arranged in parallel on one side of a transparent substrate, and the two fine metal wires cross each other vertically and horizontally. Or
Or, on both surfaces of the transparent substrate, a capacitive touch panel in which a large number of fine metal wires are arranged in parallel so that the fine metal wires intersect vertically and horizontally on each surface,
The capacitive touch panel is characterized in that an anchor layer is provided between the transparent substrate and the fine metal wires.

  The invention according to claim 2 is the capacitive touch panel according to claim 1, wherein the anchor layer is made of a three-dimensionally crosslinked organic resin.

  The invention according to claim 3 is the capacitive touch panel according to claim 1 or 2, wherein the anchor layer contains nanoparticles and has a haze value of 2 or less. .

  Moreover, the invention according to claim 4 is the capacitive touch panel according to any one of claims 1 to 3, wherein the anchor layer has a multilayer structure of one layer or two or more layers. is there.

According to the present invention, even if a biaxially stretched film having a large number of surface scratches is used, the surface scratches are embedded by the anchor layer of the present invention, so that metal cracks can be reduced and the number of defects due to wiring disconnection can be reduced. Is possible. Furthermore, Ki out to increase the adhesion between the metal film and the biaxially stretched film substrate can provide a capacitive touch panel which reliability has been improved by rubbing resistance up metal wire.

It is the conceptual top view (A) and conceptual sectional drawing (B) which showed the structure of the electrostatic capacitance touch panel which provided the anchor layer between the transparent base material and thin metal wire of this invention. It is the conceptual sectional view in which the anchor layer of this invention showed the structure of the capacitive touch panel of a multilayer structure. It is a conceptual sectional view showing the composition of a general capacitive touch panel. It is a conceptual cross-sectional view showing a capacitive touch panel in which a large number of fine metal wires are arranged in parallel on one side of a transparent substrate, and the metal fine wires intersect with each other vertically and horizontally so as to cross each other. is there.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual plan view (A) and a conceptual cross-sectional view (B) showing a configuration of a capacitive touch panel in which an anchor layer 3 is provided between a transparent substrate 1 and a thin metal wire 2. on both sides of the 1, on each side, the thin metal wires 2 are capacitive touch panel is arranged and formed in parallel a number of metallic fine wires so as to vertically and horizontally crossing.

  The anchor layer in the capacitive touch panel of the present invention has a length of several tens of μm or more and a depth of several μm in a biaxially stretched film used as a transparent substrate. Prevents tearing, fills micron surface scratches on a transparent substrate, improves adhesion between the metal film and the transparent substrate, and further improves the anchor layer hardness, It is intended to provide a capacitive touch panel that has resistance and does not cause problems such as disconnection or abnormal capacitance value.

FIG. 2 shows an anchor layer having a two-layer structure including an anchor layer (first) 3 and an anchor layer (second) 4. The smoothness improving function to fill the surface scratch, the adhesion improving function between the metal film and the transparent base material, and the hardness improving function that are held in the anchor layer are not necessarily provided in one layer, as shown in FIG. Like the first anchor layer 3 and the second anchor layer 4, a plurality of anchor layers of one layer or two or more layers separated by a functional layer may be provided.

<Transparent substrate>
As the transparent substrate, PET, acrylic film, COP (cycloolefin polymer), CO C (cyclic olefin copolymer), TAC (triacetyl cellulose), PC (polycarbonate) is available and is biaxially oriented PET film Is preferred.

<Metallic wire>
As the metal thin wire, a silver wire or a copper wire is suitable, and among them, an inexpensive copper wire is desirable. As for the fine wire, a metal thin film having a thickness of 0.5 to 12.0 μm is formed by a thin film forming method such as sputtering, and a thin wire having a line width of 2.0 to 12.0 μm is formed by a photolithography method.

<Three-dimensional crosslinked organic resin>
As the anchor layer, a three-dimensionally crosslinked resin is suitable, and an acrylic resin, a urethane resin, or an ester resin can be used.

<Nanoparticles>
Moreover, the function which prevents blocking can be given by adding 1% or less of acrylic nanoparticles as an additive.

<Haze>
When the haze value is 2 or more, the visibility as a display is deteriorated.

A biaxially stretched film as a 100μm thickness tradename XU483 (made by Toray Industries, Inc.), to form a first anchor layer by coating a 0.3 [mu] m thick acrylic resin added acrylic nanoparticles on one surface, evaporation the 2μm copper film by law, biaxial formed on one surface of the stretched film to form a fine line pattern having a line width of 3μm by photolithography (arranged parallel to the large number thin metal wires), as the thin metal wire is vertical and horizontal cross A metal wiring film touch panel of Example 1 having a haze value of 1.0, having a structure in which the insulating adhesive was laminated, was produced.
In addition, the acrylic nanoparticle to an anchor layer coating liquid used the particle size of 0.3 micrometer, and made the addition amount 0.5 mass part.

As a biaxially stretched film, a 100 μm thick product name XU483 (manufactured by Toray Industries, Inc.) was applied with acrylic resin on one side to a thickness of 2 μm to form a first anchor layer, and 0.5 μm on the first anchor layer. the ester resin obtained by adding acrylic nanoparticles thickness was applied to form a second anchor layer, a copper film of 2μm by vapor deposition, to form a single surface of a biaxially stretched film, by photolithography of the line width 3μm The metal wiring of Example 2 having a haze value of 1.2 , which is formed by forming a fine line pattern (a number of fine metal lines arranged in parallel) and overlapping the fine metal lines with an insulating adhesive so as to intersect vertically and horizontally A film touch panel was produced.
In addition, the acrylic nanoparticle to the 2nd anchor layer coating liquid used the particle size of 0.5 micrometer, and made the addition amount 0.5 mass part.

A metal wiring film touch panel of Example 3 was manufactured under the same conditions except that the second anchor layer of Example 2 was eliminated, and a metal wiring film touch panel of Example 3 having a haze value of 1.4 was manufactured.

Under the same conditions as in Example 1, a metal wiring film touch panel of Example 4 having a haze value of 1.8 was produced. However, the following points are different from the first embodiment. Specifically, an acrylic resin having a thickness of 2 μm is applied to the biaxially stretched film to form a first anchor layer. The first anchor layer to form a second anchor layer by applying a urethane resin obtained by adding acrylic nanoparticles. A fine line pattern (many fine metal wires are arranged in parallel) having a line width of 2 μm is formed on a copper film having a thickness of 2 μm formed on one side of a biaxially stretched film by vapor deposition . In addition, the acrylic nanoparticle to the 2nd anchor layer coating liquid used the particle size of 0.5 micrometer, and made the addition amount 0.5 mass part.

An acrylic resin was applied to both sides of the biaxially stretched film with a thickness of 2 μm to form a first anchor layer . A copper film having a thickness of 2 μm was formed on the first anchor layer by vapor deposition . A fine line pattern having a line width of 2 μm was formed by photolithography so that metal fine lines intersected vertically and horizontally . This produced the metal wiring film touch panel of Example 5 having a haze value of 2.5.

<Comparative Example 1>
A metal wiring film touch panel of Comparative Example 1 having a haze value of 1.5 was produced under the same conditions as in Example 1 except that the first anchor layer made of the acrylic resin in Example 1 was not provided.

<Capacitance measurement>
The capacitance value was measured using a flying prober.

<Metal tear>
Using an optical microscope, it was confirmed that the metal wire had been split.

  The results are shown in Table 1.

By providing the anchor layer between the transparent base material and the fine metal wires, there was no problem that the fine metal wires were torn and good results were obtained in the measurement of the capacitance value. Moreover, the improvement was seen by adding a nanoparticle in an anchor layer.

DESCRIPTION OF SYMBOLS 1 ... Transparent base material 2 ... Metal fine wire 3 ... Anchor layer (1st)
4 ... Anchor layer (second)
5 ... Insulating adhesive

Claims (2)

A large number of fine metal wires are arranged in parallel on one side of a transparent substrate, and two sheets are stacked so that the fine metal wires intersect vertically and horizontally,
Or, on both surfaces of the transparent substrate, a capacitive touch panel in which a large number of fine metal wires are arranged in parallel so that the fine metal wires intersect vertically and horizontally on each surface,
Having an anchor layer between the transparent substrate and the thin metal wire ;
The anchor layer has a first anchor layer and a second anchor layer in order from the transparent substrate side,
The capacitive touch panel, wherein the second anchor layer is added with 0.5 parts by mass of acrylic nanoparticles having a particle diameter of 0.5 μm . The capacitive touch panel according to claim 1, wherein the anchor layer is made of a three-dimensionally crosslinked organic resin.