JP2010033775A - Transparent conductive composite film and sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resistive film type touch panel structure with endurance performance greatly improved, and with optical performance, electric performance, and environment resistance generally maintained at a high and balanced level; and to provide a top substrate layer as well as a bottom substrate layer for the same. <P>SOLUTION: The transparent conductive composite film A (or the sheet B) has first conductive layers 2, 5 as a conductive polymer film or a carbon nanotube layer formed on one surface of a transparent film 1 (or a sheet 4), and further, second conductive layers 3, 6 as an ITO film (an indium tin oxide film) formed on the surface of the first conductive layer. The resistive film type touch panel structure uses these as a top substrate layer or a bottom substrate layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a transparent conductive composite film and a sheet, and further relates to a resistive touch panel structure using these films and sheets.

  Recently, the use of a resistive touch panel as a mobile information terminal by finger input or pen input is expanding. The resistive touch panel has an advantage that it can be easily input with a finger or a normal pen without using a special pen, and the cost reduction is relatively simple. On the other hand, the resistive touch panel has an air layer with a spacer between the upper substrate and the lower substrate, and physically contacts (touches) the transparent conductive film formed on the surface of the upper substrate and the lower substrate. It is structured to sense the contact position. Glass, polymer film, plastic sheet or the like is used as the substrate material for the upper and lower substrates of this touch panel, and has various advantages and disadvantages based on the combination of the respective substrate materials.

In particular, polymer films (such as polyethylene terephthalate film and polycarbonate film) as the material of the upper substrate (touch surface) are widely used due to many advantages such as non-breaking, light weight, thinness, and excellent flexibility. Has been used. When a polymer film is used as the upper substrate, local touch pressure is easily sensed due to its excellent flexibility. On the other hand, the use of a polymer film substrate as the upper substrate has various advantages as described above, but has a problem to be further improved in mounting an actual touch panel structure.
As a transparent conductive film for a touch panel, there has been no film having a level in which durability, optical performance, electrical performance, and environmental resistance are comprehensively balanced, and these performances are all satisfied. For example, commonly used ITO (Indium
The Tin Oxide) film is excellent in optical performance, electrical performance and environmental resistance, but has insufficient sliding writing durability. On the other hand, although the conductive polymer film is excellent in durability (for example, sliding writing durability), it cannot be said that optical performance and environmental resistance are sufficient.

Therefore, as a measure for improving various performances, Patent Document 1 proposes means for forming a two-layer structure of a hard coat layer and a SiOx film on the surface opposite to the surface on which the ITO film is formed. Proposed a two-layer structure in which the composition of tin oxide and indium oxide in the ITO film was changed, and in Patent Document 3, an underlayer of SnO or ZnO was interposed between the ITO film and the transparent film, and ITO was used. It has been proposed to control the surface roughness (Ra) of the film surface within a certain range. However, none of these proposals can be said to have obtained the above-mentioned various performances comprehensively.
: JP 2006-134867 A : JP 2006-244771 A : JP 2007-287450 A

Therefore, the present inventor has a structure in which a conductive polymer film or a carbon nanotube layer is formed on one surface of a transparent film and an ITO film is laminated on the surface, and the overall performance is well balanced and excellent. The present invention has been found to be usable as a transparent conductive film or sheet.
According to the present invention, the following transparent conductive composite film and sheet, and a resistance film type touch panel structure using the same are provided.
(1) A first conductive layer that is a conductive polymer film or a carbon nanotube layer is formed on one surface of a transparent film, and an ITO film (Indium) is formed on the surface of the first conductive layer.
A transparent conductive composite film in which a second conductive layer (Tin Oxide film) is formed.
(2) The composite film according to (1), wherein the transparent film is a polyethylene terephthalate (PET) film or a polycarbonate (PC) film having a thickness of 50 μm to 200 μm.
(3) The composite film according to (1), wherein the first conductive layer has a thickness of 1 nm to 100 nm.
(4) The composite film according to (1), wherein the first conductive layer is a thiophene polymer film.
(5) The composite film according to (1), wherein the first conductive layer is a single-walled carbon nanotube layer.
(6) The composite film as described in (1) above, having a light transmittance of 85% or more and a surface resistance value of 100Ω / □ to 3000Ω / □.
(7) A first conductive layer that is a conductive polymer film or a carbon nanotube layer is formed on one surface of the transparent sheet, and an ITO film (Indium) is further formed on the surface of the first conductive layer.
A transparent conductive composite sheet, wherein a second conductive layer (Tin Oxide film) is formed.
(8) The composite sheet according to (7), wherein the transparent sheet is a glass sheet, a polycarbonate (PC) sheet, or a polycycloolefin sheet having a thickness of 500 μm to 2 mm.
(9) The composite sheet according to (7), wherein the first conductive layer has a thickness of 1 nm to 100 nm.
(10) The composite sheet according to (7), wherein the first conductive layer is a thiophene polymer film.
(11) The composite sheet according to (7), wherein the first conductive layer is a single-walled carbon nanotube layer.
(12) The composite sheet according to (7), which has a light transmittance of 85% or more and a surface resistance value of 100Ω / □ to 3000Ω / □.
(13) A resistive touch panel structure in which the composite film according to (1) is configured as an upper substrate layer.
(14) A resistive touch panel structure in which the composite film described in (1) is used as an upper substrate layer and the composite sheet described in (7) is used as a lower substrate layer.
(15) A resistive touch panel structure in which the composite sheet according to (7) is configured as a lower substrate layer.

  The transparent conductive composite film and the transparent conductive composite sheet of the present invention are used as an upper substrate layer and a lower substrate layer for a touch panel, respectively, so that the durability, optical performance, electrical performance and environmental resistance are well balanced. Moreover, it is possible to obtain a touch panel structure that has reached a level that satisfies all of these performances. Therefore, according to the present invention, it is possible to provide a touch panel structure having a good balance between the above four performances and high practical value, and also to provide a transparent conductive composite film and a transparent conductive composite sheet used therefor.

Hereinafter, the transparent conductive composite film of the present invention, the transparent conductive composite sheet, and the touch panel structure using these films (or sheets) will be described in detail sequentially.
(A) a transparent conductive composite film;
The basic configuration will be described with reference to FIG. In FIG. 1, A is a schematic view showing a right-angle cross-sectional structure from the surface of the transparent conductive composite film. As shown in FIG. 1, in the transparent conductive composite film A, a first conductive layer 2 which is a conductive polymer film or a carbon nanotube layer is formed on one surface of the transparent film 1, and further An ITO film (Indium) is formed on the surface of the first conductive layer.
The second conductive layer 3 (Tin Oxide film) is formed.

In the transparent conductive composite film A, the transparent film 1 is a transparent polymer film having a thickness of 50 μm to 200 μm, preferably 80 μm to 190 μm, particularly preferably 100 μm to 180 μm. As the transparent film, a polyester film, preferably a polyethylene terephthalate (PET) film or a polycarbonate (PC) film is excellent. Particularly preferred is a polyethylene terephthalate (PET) film.
A first conductive layer 2 is formed on one surface of the transparent film 1. The first conductive layer 2 is a conductive polymer film or a carbon nanotube layer. The thickness of the first conductive layer 2 is 1 nm to 100 nm, preferably 5 nm to 80 nm.
In order to form a transparent conductive polymer film on the surface of the transparent film, a conductive polymer solution or dope may be applied or printed on the surface of the transparent film. Any conductive polymer may be used as long as it has excellent transparency and electrical conductivity.

  As specific examples of the conductive polymer film, it is advantageous that the main chain is an organic polymer having a π-conjugated system, for example, polypyrroles, polythiophenes, polyacetylenes, polyphenylenes, polyphenylene vinylenes. , Polyanilines, polyacenes, polythiophene vinylenes, and copolymers thereof. Among these, polypyrroles, polythiophenes, and polyanilines are preferable from the viewpoints of stability and film formation. In particular, polypyrrole, polythiophene, poly (N-methylpyrrole), poly (3-methylthiophene), poly (3-methoxythiophene), poly (3,4-ethylenedioxythiophene) and copolymers thereof are preferable. Of these, thiophene polymers are particularly preferred. Solvents used to prepare these conductive polymer solutions include water; polar organic solvents such as N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, acetonitrile and benzonitrile; phenol Phenols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; hydrocarbons such as hexane, benzene, toluene and xylene; and hydrocarbons such as dioxane and diethyl ether Examples include ethers. These solvents are used alone or as a mixed solvent of two or more.

Examples of the method for applying or printing the above-described conductive polymer solution on the transparent film 1 include dipping, comma coating, spray coating, roll coating, and gravure printing. It is desirable to cure the thin film after application.
The first conductive layer 2 may be a carbon nanotube layer. The carbon nanotubes forming the carbon nanotube layer may be single-walled carbon nanotubes, multi-walled carbon nanotubes or multi-walled carbon nanotubes, but single-walled carbon nanotubes are preferred. The fiber length of the carbon nanotube is 100 nm to 100 μm, preferably 1 μm to 10 μm. The carbon nanotube layer only needs to form a carbon nanotube net and maintain transparency.
In order to form a carbon nanotube layer on the surface of the transparent film 1, a dispersion composed of carbon nanotubes, a dispersant and a solvent is prepared, and this dispersion is applied to the surface of the transparent film and heated to remove the dispersant and the solvent. Is preferred. The dispersant used here is preferably a primary amine such as n-propylamine, iso-propylamine, n-butylamine and sec-butylamine, and the solvent is ketones (acetone, methyl ethyl ketone, cyclohexanone, etc.), esters. (Methyl acetate, ethyl acetate, etc.), hydrocarbons (pentane, hexane, toluene, xylene, etc.), ethers (diethyl ether, ethyl cellosolve, butyl cellosolve, dioxane, etc.), halogenated hydrocarbons (methylene chloride, chlorobenzene, etc.) ) And alcohols (methanol, ethanol, propanol, etc.). If necessary, a small proportion of a thermoplastic resin such as a polyester resin, a polyolefin resin, or an acrylic resin can be added to the dispersion.

A second conductive layer 3 is formed on the surface of the first conductive layer 2 of the transparent film on which the first conductive layer 2 is formed. The second conductive layer 3 is made of an ITO film (Indium
Tin Oxide film). This ITO film can be formed on the surface of the first conductive layer 2 by sputtering or CVD. This ITO film preferably has a thickness of 10 to 50 nm.
The transparent conductive composite film A of the present invention basically has a three-layer structure of transparent film 1 / first conductive layer 2 / second conductive layer 3 as described above. The composite film A desirably has a surface resistance in the range of 300 to 3000 Ω / □, preferably 400 to 2500 Ω / □, and the transparency is such that the light transmittance (wavelength 550 nm) is 85% or more, preferably 87%. As mentioned above, it is particularly advantageous that the content is in the range of 88 to 96%. This composite film is advantageously used as the upper substrate layer of the touch panel structure.
(B) a transparent conductive composite sheet;
The basic configuration will be described with reference to FIG. In FIG. 1, a schematic view showing a right-angle cross-sectional structure from the surface of the transparent conductive composite sheet is shown as B. As shown in FIG. 1, in the transparent conductive composite sheet B, a first conductive layer that is a conductive polymer film or a carbon nanotube layer is formed on one surface of the transparent sheet, and the first ITO film (Indium) on the surface of the conductive layer of
A second conductive layer (Tin Oxide film) is formed.

In the transparent conductive composite sheet B, the transparent sheet 4 may be a transparent sheet, but specifically, a glass sheet, a polycarbonate (PC) sheet or a polycycloolefin sheet is preferable, and a glass sheet or a polycarbonate sheet is particularly preferable. The transparent sheet 4 has a thickness of 500 μm to 2 mm, preferably 800 μm to 1.8 mm.
When the transparent sheet 4 of the composite sheet B is a polycarbonate (PC) sheet, the polycarbonate sheet is a polycarbonate sheet obtained using bisphenol A as a dihydric phenol component. From the viewpoints of heat resistance, heat resistance and availability. This polycarbonate (PC) is also suitable as a material for the transparent film 2 of the transparent conductive composite film A described above.

A first conductive layer 5 and a second conductive layer 6 are formed in this order on the surface of one side of the transparent sheet 4. The first conductive layer 5 formed on the surface of the transparent sheet 4 is a transparent conductive polymer film or a carbon nanotube layer. The thickness of the first conductive layer 5 is 1 nm to 100 nm, preferably 5 nm to 80 nm.
The method for forming the conductive polymer film on the surface of the transparent sheet 4 and the type of the conductive polymer are the same as the method described in the conductive polymer film of the first conductive layer 2 in the transparent conductive composite film A. Since the kind of polymer can be similarly adopted, the description is omitted here.
When the first conductive layer 5 is a carbon nanotube layer, the type of carbon nanotube layer and the method for forming the carbon nanotube layer are the same as those of the carbon nanotube layer described in the first conductive layer 2 of the transparent conductive composite film A. Since the type and formation method can be similarly adopted, the description thereof is omitted here.
A second conductive layer 6 is formed on the surface of the first conductive layer 5 of the transparent sheet 4 on which the first conductive layer 5 is formed. The second conductive layer 6 is made of an ITO film (Indium
Tin Oxide film). This ITO film can be formed on the surface of the first conductive layer 5 by sputtering or CVD. This ITO film preferably has a thickness of 10 to 50 nm.

The transparent conductive composite sheet B of the present invention basically has a three-layer structure of transparent sheet 4 / first conductive layer 5 / second conductive layer 6 as described above. The composite sheet B desirably has a surface resistance in the range of 300 to 3000 Ω / □, preferably 400 to 2500 Ω / □, and the transparency is 80% or more, preferably 85%, of light transmittance (wavelength 550 nm). As described above, it is particularly preferable that the content is in the range of 86 to 96%. This composite sheet B is advantageously used as the lower substrate layer of the touch panel structure.
(C) Resistance film type touch panel structure The above-described transparent conductive composite film A and transparent conductive composite sheet B of the present invention can be used as an upper substrate layer and a lower substrate layer of a resistance film type touch panel structure, respectively. .
Thus, according to the present invention, the following resistive film type touch panel structures (1) to (3) are provided.
(1) A resistive touch panel structure using the transparent conductive composite film A of the present invention as an upper substrate layer and a conventional lower substrate layer. Here, as a conventional one, a glass sheet or a polycarbonate (PC) sheet on which an ITO film is formed is advantageous.
(2) A resistive touch panel structure configured using the transparent conductive composite film A of the present invention as an upper substrate and the transparent conductive composite sheet B as a lower substrate layer. In this structure, the composite film A and the composite sheet B are arranged such that the conductive layer 3 and the conductive layer 6 face each other, as shown in FIG.
(3) A resistive touch panel structure using the transparent conductive composite sheet B of the present invention as a lower substrate layer and a conventional one as an upper substrate layer. Here, as a conventional film, a polyethylene terephthalate (PET) film or a polycarbonate (PC) film having an ITO film formed on the surface is advantageous.
Hereinafter, the present invention will be described specifically by way of examples.

Comparative Example 1

An ITO film (Indium) is formed on one side of a 188 μm thick polyethylene terephthalate (PET) film by sputtering.
Tin Oxide film) was formed to form an upper substrate layer. On the other hand, a glass substrate having a thickness of 1.1 mm with an ITO film formed on one side was used as the lower substrate layer. The upper substrate layer and the lower substrate layer were arranged so that the ITO films faced each other to form a resistive film type touch panel structure.
The touch panel structure was subjected to a writing sliding test and a keystroke test. The results are shown in Table 1 below.

A polythiophene (Polythiophene) conductive polymer was applied to one side of a 188 μm thick polyethylene terephthalate (PET) film to a thickness of 40 nm. Thereafter, an ITO film was formed on the polymer film surface by a sputtering method to form an upper substrate layer. The upper substrate layer had a light transmittance of 88% and a surface resistance value of 500Ω / □. On the other hand, a glass substrate having a thickness of 1.1 mm having an ITO film formed on one side was used as the lower substrate. The upper substrate layer and the lower substrate layer were arranged so that the ITO films faced each other to form a resistive film type touch panel structure.
The touch panel structure was subjected to a writing sliding test and a keystroke test. The results are shown in Table 1 below. As is apparent from the results in Table 1, the use of the transparent conductive composite film of the present invention as the upper substrate layer significantly improved the writing sliding test and the keystroke durability compared to the conventional product (Comparative Example 1). I was able to improve. Moreover, optical characteristics and electrical characteristics were almost the same as the conventional products.

A conductive layer made of carbon nanotubes was applied on one side of a polycarbonate (PC) film having a thickness of 100 μm so as to have a thickness of 20 nm. Thereafter, an ITO film was formed on the surface of the conductive layer by sputtering to form an upper substrate layer. The upper substrate layer had a light transmittance of 90% and a surface resistance value of 700Ω / □. On the other hand, a glass substrate having a thickness of 1.1 mm having an ITO film formed on one side was used as the lower substrate. The upper substrate layer and the lower substrate layer were arranged so that the ITO films faced each other to form a resistive film type touch panel structure.
The touch panel structure was subjected to a writing sliding test and a keystroke test. The results are shown in Table 1 below. As is apparent from the results in Table 1, the use of the transparent conductive composite film of the present invention as the upper substrate layer greatly improves the writing sliding test and keystroke durability compared to the conventional product (Comparative Example 1). It was possible to improve. Moreover, optical characteristics and electrical characteristics were almost the same as the conventional products.

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打鍵試験条件；８Ｒシリコンゴム，荷重２５０ｇ，１０回／秒打鍵 The same upper substrate layer as shown in Example 1 was used as the upper substrate layer. On the other hand, a polythiophene-based conductive polymer is applied on one side of a 1 mm thick polycarbonate (PC) sheet to a thickness of 40 nm, and then an ITO film is formed on the polymer film surface by sputtering. Thus, a lower substrate layer was formed. The upper substrate layer had a light transmittance of 90% and a surface resistance value of 500Ω / □. The upper substrate layer and the lower substrate layer were arranged so that the ITO films faced each other to form a resistive film type touch panel structure.
The touch panel structure was subjected to a writing sliding test and a keystroke test. The results are shown in Table 1 below. As is apparent from the results in Table 1, by using the transparent conductive composite film of the present invention as the upper substrate layer and the transparent conductive composite sheet as the lower substrate layer, compared with the conventional product (Comparative Example 1). Both the writing sliding test and the keying durability were remarkably improved. Moreover, optical characteristics and electrical characteristics were almost the same as the conventional products.

Writing sliding test conditions; writing pen 0.8R polyacetal resin, load 250g, letter writing keying test conditions; 8R silicone rubber, load 250g, 10 times / second keying

It is a schematic diagram which shows the right-angled cross-section structure from the surface of the transparent conductive composite film (A) and transparent conductive composite sheet (B) of this invention.

Explanation of symbols

A: transparent conductive composite film B; transparent conductive composite sheet 1; transparent film 2; first conductive layer 3; second conductive layer 4; transparent sheet 5; first conductive layer 6; The conductive layer

Claims (15)

A first conductive layer that is a conductive polymer film or a carbon nanotube layer is formed on one surface of the transparent film, and an ITO film (Indium) is formed on the surface of the first conductive layer.
A transparent conductive composite film in which a second conductive layer (Tin Oxide film) is formed.   The composite film according to claim 1, wherein the transparent film is a polyethylene terephthalate (PET) film or a polycarbonate (PC) film having a thickness of 50 μm to 200 μm.   The composite film according to claim 1, wherein the first conductive layer has a thickness of 1 nm to 100 nm.   The composite film according to claim 1, wherein the first conductive layer is a thiophene polymer film.   The composite film according to claim 1, wherein the first conductive layer is a single-walled carbon nanotube layer.   2. The composite film according to claim 1, having a light transmittance of 85% or more and a surface resistance value of 100Ω / □ to 3000Ω / □. A first conductive layer that is a conductive polymer film or a carbon nanotube layer is formed on one surface of the transparent sheet, and an ITO film (Indium) is further formed on the surface of the first conductive layer.
A transparent conductive composite sheet, wherein a second conductive layer (Tin Oxide film) is formed.   The composite sheet according to claim 7, wherein the transparent sheet is a glass sheet, a polycarbonate (PC) sheet, or a polycycloolefin sheet having a thickness of 500 μm to 2 mm.   The composite sheet according to claim 7, wherein the first conductive layer has a thickness of 1 nm to 100 nm.   The composite sheet according to claim 7, wherein the first conductive layer is a thiophene polymer film.   The composite sheet according to claim 7, wherein the first conductive layer is a single-walled carbon nanotube layer.   The composite sheet according to claim 7, which has a light transmittance of 85% or more and a surface resistance value of 100Ω / □ to 3000Ω / □.   A resistive touch panel structure comprising the composite film according to claim 1 as an upper substrate layer.   A resistive touch panel structure comprising the composite film according to claim 1 as an upper substrate layer and the composite sheet according to claim 7 as a lower substrate layer. A resistive touch panel structure comprising the composite sheet according to claim 7 as a lower substrate layer.

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