JP5337494B2 - Transparent conductive sheet and touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent conductive sheet capable of securing a sufficient visible ray permeation rate in spite of excellent color reproductivity. <P>SOLUTION: The transparent conductive sheet 10a has a transparent base material 11, at least one transparent conductive layer 12 including &pi;-conjugated system conductive polymer and poly-anion, and a color correction layer 13 including colored phosphor of a complementary color to the color of the transparent conductive layer 12. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a transparent conductive sheet used for a transparent electromagnetic wave shield of a display, a touch panel and the like. The present invention also relates to a resistive film type touch panel.

In a display such as a plasma display, a transparent conductive sheet is used as a transparent electromagnetic wave shield. Moreover, the transparent conductive sheet is also used for the touch panel installed on the liquid crystal display device.
As a transparent conductive sheet for these applications, a sheet in which a tin-doped indium oxide film (hereinafter referred to as ITO film) is formed on a transparent substrate such as a glass substrate or a polyethylene terephthalate sheet has been widely used. However, since the ITO film has low flexibility, it has been studied to use a conductive film containing a π-conjugated conductive polymer such as polythiophene, polypyrrole, polyaniline or the like instead of the ITO film (for example, Patent Document 1). reference).

However, since the transparent conductive sheet using the π-conjugated conductive polymer is colored from green to blue, it is not suitable for applications requiring accurate color reproducibility.
Therefore, in Patent Document 2, it is proposed to provide a complementary color filter for the color developed by the π-conjugated conductive polymer. In this method, a part of the wavelength band that causes coloring is shielded, and the color of the transmitted light is corrected to improve color reproducibility.

JP 2007-261968 A JP 2003-334891 A

However, in the method described in Patent Document 2, since the light is transmitted through the colored filter, the light transmittance tends to decrease. For this reason, it has been difficult to apply to portable devices that are particularly limited in power consumption and large screen displays that require high contrast.
Accordingly, an object of the present invention is to provide a transparent conductive sheet and a touch panel that can ensure sufficient visible light transmittance despite excellent color reproducibility.

The present invention has the following configuration.
[1] A transparent substrate, at least one transparent conductive layer containing a π-conjugated conductive polymer and a polyanion, and a color correction layer containing a colored phosphor complementary to the color of the transparent conductive layer A transparent conductive sheet characterized by comprising:
[2] The transparent according to [1], wherein the color correction layer is disposed between the transparent substrate and the transparent conductive layer or on the surface of the transparent substrate opposite to the transparent conductive layer. Conductive sheet.
[3] A pair of transparent conductive sheets having a transparent base material and a transparent conductive layer containing a π-conjugated conductive polymer and a polyanion are provided, and the transparent conductive layers of the transparent conductive sheets are arranged to face each other. Touch panel
At least one of the transparent conductive sheets is the transparent conductive sheet according to [2].

  Although the transparent conductive sheet and touch panel of the present invention are excellent in color reproducibility, sufficient visible light transmittance can be secured.

It is sectional drawing which shows one embodiment of the transparent conductive sheet of this invention. It is sectional drawing which shows the other embodiment example of the transparent conductive sheet of this invention. It is sectional drawing which shows one embodiment of the touchscreen of this invention. It is sectional drawing which shows the movable electrode sheet which comprises the touch panel of Example 2 and Comparative Example 2. It is sectional drawing which shows the movable electrode sheet which comprises the touch panel of Example 2 and Comparative Example 2. It is a schematic diagram which shows the apparatus used in order to confirm operation | movement of the touchscreen of Example 2 and Comparative Example 2. FIG.

<Transparent conductive sheet>
An embodiment of the transparent conductive sheet of the present invention will be described.
In FIG. 1, the transparent conductive sheet of this embodiment is shown. The transparent conductive sheet 10 a includes a transparent base material 11, a transparent conductive layer 12 provided on one surface of the transparent base material 11, and a color correction layer 13 provided on the other surface of the transparent base material 11. .

(Transparent substrate)
Examples of the transparent substrate 11 include polyethylene terephthalate (PET), polyethylene naphthalate, acrylic resin, polyethersulfone, polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, cellulose triacetate, and cellulose acetate. Examples include films or sheets such as propionate. Moreover, a glass substrate, a silicon substrate, etc. can also be used.

(Transparent conductive layer)
The transparent conductive layer 12 contains a π-conjugated conductive polymer and a polyanion.
[Π-conjugated conductive polymer]
The π-conjugated conductive polymer is not particularly limited as long as the main chain is an organic polymer composed of a π-conjugated system. For example, polypyrroles, polythiophenes, polyacetylenes, polyphenylenes, polyphenylene vinylenes, Examples thereof include polyanilines, polyacenes, polythiophene vinylenes, and copolymers thereof. From the viewpoint of stability in air, polypyrroles, polythiophenes and polyanilines are preferred.
Even if the π-conjugated conductive polymer remains unsubstituted, sufficient conductivity can be obtained. However, in order to further improve conductivity and compatibility, an alkyl group, a carboxy group, a sulfo group, an alkoxy group, a hydroxy group, It is preferable to introduce a functional group such as a group into the π-conjugated conductive polymer.

  Specific examples of the π-conjugated conductive polymer include polypyrrole, poly (N-methylpyrrole), poly (3-methylpyrrole), poly (3-ethylpyrrole), poly (3-n-propylpyrrole), poly (3-butylpyrrole), poly (3-octylpyrrole), poly (3-decylpyrrole), poly (3-dodecylpyrrole), poly (3,4-dimethylpyrrole), poly (3,4-dibutylpyrrole) , Poly (3-carboxypyrrole), poly (3-methyl-4-carboxypyrrole), poly (3-methyl-4-carboxyethylpyrrole), poly (3-methyl-4-carboxybutylpyrrole), poly (3 -Hydroxypyrrole), poly (3-methoxypyrrole), poly (3-ethoxypyrrole), poly (3-butoxypyrrole), poly (3-methyl) -4-hexyloxypyrrole), poly (thiophene), poly (3-methylthiophene), poly (3-ethylthiophene), poly (3-propylthiophene), poly (3-butylthiophene), poly (3-hexyl) Thiophene), poly (3-heptylthiophene), poly (3-octylthiophene), poly (3-decylthiophene), poly (3-dodecylthiophene), poly (3-octadecylthiophene), poly (3-bromothiophene) , Poly (3-chlorothiophene), poly (3-iodothiophene), poly (3-cyanothiophene), poly (3-phenylthiophene), poly (3,4-dimethylthiophene), poly (3,4-dibutyl) Thiophene), poly (3-hydroxythiophene), poly (3-methoxythiophene), poly (3 -Ethoxythiophene), poly (3-butoxythiophene), poly (3-hexyloxythiophene), poly (3-heptyloxythiophene), poly (3-octyloxythiophene), poly (3-decyloxythiophene), poly (3-dodecyloxythiophene), poly (3-octadecyloxythiophene), poly (3-methyl-4-methoxythiophene), poly (3,4-ethylenedioxythiophene), poly (3-methyl-4-ethoxy) Thiophene), poly (3-carboxythiophene), poly (3-methyl-4-carboxythiophene), poly (3-methyl-4-carboxyethylthiophene), poly (3-methyl-4-carboxybutylthiophene), polyaniline , Poly (2-methylaniline), poly (3-isobutyla) Phosphorus), poly (2-aniline sulfonic acid), poly (3-aniline sulfonic acid), and the like. Among them, poly (3,4-ethylenedioxythiophene) is preferable from the viewpoint of conductivity and heat resistance.

[Polyanion]
Examples of the polyanion include a substituted or unsubstituted polyalkylene, a substituted or unsubstituted polyalkenylene, a substituted or unsubstituted polyimide, a substituted or unsubstituted polyamide, and a substituted or unsubstituted polyester having an anionic group. Examples thereof include a polymer composed only of a structural unit, and a polymer composed of a structural unit having an anionic group and a structural unit not having an anionic group.

A polyalkylene is a polymer whose main chain is composed of repeating methylenes.
Polyalkenylene is a polymer composed of structural units containing one unsaturated double bond (vinyl group) in the main chain.
As polyimide, pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, 2,2 ′-[4,4′-di (dicarboxyphenyloxy) phenyl] propane dianhydride And polyimides from acid anhydrides such as oxydiamine, paraphenylenediamine, metaphenylenediamine, benzophenonediamine and the like.
Examples of the polyamide include polyamide 6, polyamide 6,6, polyamide 6,10 and the like.
Examples of the polyester include polyethylene terephthalate and polybutylene terephthalate.

  When the polyanion has a substituent, examples of the substituent include an alkyl group, a hydroxy group, an amino group, a carboxy group, a cyano group, a phenyl group, a phenol group, an ester group, and an alkoxy group. In view of solubility in an organic solvent, heat resistance, compatibility with a resin, and the like, an alkyl group, a hydroxy group, a phenol group, and an ester group are preferable.

Examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, decyl, and dodecyl, and cycloalkyl groups such as cyclopropyl, cyclopentyl, and cyclohexyl. It is done.
Examples of the hydroxy group include a hydroxy group bonded directly or via another functional group to the main chain of the polyanion. Examples of the other functional group include an alkyl group having 1 to 7 carbon atoms and an alkyl group having 2 to 7 carbon atoms. An alkenyl group, an amide group, an imide group, etc. are mentioned. Hydroxy groups are substituted at the ends or in these functional groups.
Examples of the amino group include an amino group bonded to the main chain of the polyanion directly or via another functional group. Examples of the other functional group include an alkyl group having 1 to 7 carbon atoms and an alkyl group having 2 to 7 carbon atoms. An alkenyl group, an amide group, an imide group, etc. are mentioned. The amino group is substituted at the end or in these functional groups.
Examples of the phenol group include a phenol group bonded directly or via another functional group to the main chain of the polyanion. Examples of the other functional group include an alkyl group having 1 to 7 carbon atoms and an alkyl group having 2 to 7 carbon atoms. An alkenyl group, an amide group, an imide group, etc. are mentioned. The phenol group is substituted at the end or in these functional groups.

Examples of the polyalkylene having a substituent include polyethylene, polypropylene, polybutene, polypentene, polyhexene, polyvinyl alcohol, polyvinylphenol, poly (3,3,3-trifluoropropylene), polyacrylonitrile, polyacrylate, polystyrene and the like. it can.
Specific examples of polyalkenylene include propenylene, 1-methylpropenylene, 1-butylpropenylene, 1-decylpropenylene, 1-cyanopropenylene, 1-phenylpropenylene, 1-hydroxypropenylene, 1-butenylene, 1-methyl-1-butenylene, 1-ethyl-1-butenylene, 1-octyl-1-butenylene, 1-pentadecyl-1-butenylene, 2-methyl-1-butenylene, 2-ethyl-1-butenylene, 2- Butyl-1-butenylene, 2-hexyl-1-butenylene, 2-octyl-1-butenylene, 2-decyl-1-butenylene, 2-dodecyl-1-butenylene, 2-phenyl-1-butenylene, 2-butenylene, 1-methyl-2-butenylene, 1-ethyl-2-butenylene, 1-octyl-2-butenylene 1-pentadecyl-2-butenylene, 2-methyl-2-butenylene, 2-ethyl-2-butenylene, 2-butyl-2-butenylene, 2-hexyl-2-butenylene, 2-octyl-2-butenylene, 2- Decyl-2-butenylene, 2-dodecyl-2-butenylene, 2-phenyl-2-butenylene, 2-propylenephenyl-2-butenylene, 3-methyl-2-butenylene, 3-ethyl-2-butenylene, 3-butyl 2-butenylene, 3-hexyl-2-butenylene, 3-octyl-2-butenylene, 3-decyl-2-butenylene, 3-dodecyl-2-butenylene, 3-phenyl-2-butenylene, 3-propylenephenyl- 2-butenylene, 2-pentenylene, 4-propyl-2-pentenylene, 4-propyl-2-pentenylene, 4- Tyl-2-pentenylene, 4-hexyl-2-pentenylene, 4-cyano-2-pentenylene, 3-methyl-2-pentenylene, 4-ethyl-2-pentenylene, 3-phenyl-2-pentenylene, 4-hydroxy- Examples thereof include polymers containing one or more structural units selected from 2-pentenylene, hexenylene and the like.

Examples of the anion group of the _{^{polyanion, -O-SO 3 - X +}} , -SO 3 - X +, -COO - X + (. X + is the hydrogen ion in each of the formulas, represents an alkali metal ion), and the like. That is, the polyanion is a polymer acid containing a sulfo group and / or a carboxy group. Among these, from the viewpoint of doping effects on the π-conjugated conductive _{^{polymer, -SO 3 - X +, -COO}} - X + are preferable.
Moreover, it is preferable that this anion group is arrange | positioned in the principal chain of a polyanion adjacently or at fixed intervals.

  Among the polyanions, polyisoprene sulfonic acid, a copolymer containing polyisoprene sulfonic acid, a polysulfoethyl methacrylate, a copolymer containing polysulfoethyl methacrylate, and poly (4-sulfone) are preferable in view of solvent solubility and conductivity. Butyl methacrylate), a copolymer containing poly (4-sulfobutyl methacrylate), a polymethacryloxybenzenesulfonic acid, a copolymer containing polymethacryloxybenzenesulfonic acid, a polystyrenesulfonic acid, a copolymer containing polystyrenesulfonic acid, etc. Is preferred.

  The degree of polymerization of the polyanion is preferably in the range of 10 to 100,000 monomer units, and more preferably in the range of 50 to 10,000 from the viewpoint of solvent solubility and conductivity.

  The content of the polyanion is preferably in the range of 0.1 to 10 mol, and more preferably in the range of 1 to 7 mol, with respect to 1 mol of the π-conjugated conductive polymer. When the polyanion content is less than 0.1 mol, the doping effect on the π-conjugated conductive polymer tends to be weak, and the conductivity may be insufficient. In addition, the dispersibility and solubility in the solvent are reduced, making it difficult to obtain a uniform dispersion. On the other hand, when the polyanion content is more than 10 mol, the content of the π-conjugated conductive polymer is decreased, and it is difficult to obtain sufficient conductivity.

The polyanion is coordinated to the π-conjugated conductive polymer. Therefore, the π-conjugated conductive polymer and the polyanion form a complex.
The total content of the π-conjugated conductive polymer and the polyanion is 0.05 to 5.0% by mass, and preferably 0.1 to 4.0% by mass. When the total content of the π-conjugated conductive polymer and the polyanion is less than 0.05% by mass, sufficient conductivity may not be obtained. The layer 12 may not be obtained.

[Inorganic conductive particles]
The transparent conductive layer 12 preferably contains inorganic conductive particles in that the contact resistance can be reduced.
Examples of the inorganic conductive component constituting the inorganic conductive particles include conductive inorganic oxides, metal particles, and carbon particles.
As the conductive inorganic oxide, for example, tin oxide, or tin oxide doped with at least one element selected from the group consisting of antimony, zinc, and fluorine, indium oxide, indium oxide with tin, zinc, One doped with at least one element selected from the group consisting of tellurium, silver, gallium, zirconium, hafnium, magnesium, antimony pentoxide, zinc oxide, or zinc oxide with aluminum, gallium, indium, boron, fluorine, Examples include those doped with at least one element selected from the group consisting of manganese.
Examples of the metal particles include particles of silver, gold, nickel, and the like.
Examples of the carbon particles include carbon black.

(Color correction layer)
The color correction layer 13 is a layer containing a colored phosphor that is complementary to the color of the transparent conductive layer 12. As the colored phosphor, a photoluminescence phosphor that emits light excited by a light beam transmitted through the color correction layer 13 is preferable.
Examples of the photoluminescent phosphor include yttrium, aluminum, and garnet phosphors activated with cerium (hereinafter referred to as YAG phosphors).
In the present invention, the YAG phosphor is interpreted broadly. That is, a part or all of yttrium is replaced with at least one element selected from the group consisting of lutetium (Lu), scandium (Sc), La (lanthanum), Gd (gadolinium), and samarium (Sm), aluminum In which part or all of is substituted with one or both of gallium and indium. YAG fluorescent material is _{preferably, (RE 1-x Sm x} ) 3 (Al y Ga 1-y) 5 O 12: Ce ( provided that, 0 ≦ x <1,0 ≦ y ≦ 1, RE is Y and / Or Gd).

Since the YAG phosphor has a garnet structure, it has high resistance to heat, light and moisture. Moreover, the peak of the excitation spectrum can be made around 450 nm. The emission spectrum is a broad spectrum having a peak near 580 nm and extending to around 700 nm.
The YAG-based phosphor can increase the excitation emission efficiency in the long wavelength region of 460 nm or more by containing gadolinium, and the emission peak wavelength shifts to the long wavelength side as the gadolinium content increases. The entire emission wavelength also moves to the long wavelength side. Therefore, as the gadolinium content is increased, an emission color with a strong redness can be obtained. In addition, as the content of gadolin increases, the emission luminance of blue light by photoluminescence decreases.
Such a YAG-based phosphor is more likely to exhibit a color that is complementary to the color of the transparent conductive layer 12.

Further, when a part of aluminum is replaced with gallium, the emission wavelength shifts to the short wavelength side, and when a part of yttrium is replaced with gadolinium, the emission wavelength shifts to the long wavelength side.
When a part of aluminum is replaced with gallium, it is preferable to set the molar ratio of aluminum: gallium = 6: 4 to 1: 1 in consideration of the light emission efficiency and the light emission wavelength. Moreover, when substituting a part of yttrium with gadolinium, it is preferable to set it as a molar ratio of yttrium: gadolinium = 9: 1 to 1: 9 in view of luminous efficiency and emission wavelength. A molar ratio is more preferable.

  In addition to YAG-based phosphors, anionic coumarin, cationic coumarin, anionic naphthalimide dye, pyranine (anionic pyrene dye), neutral, anionic or cationic perylene dye, Yellow or orange fluorescent dyes based on chromophores such as anionic xanthene dyes can be used.

  The content of the colored phosphor in the color correction layer 13 is preferably 10 to 65% by mass when the entire color correction layer 13 is 100% by mass. When the content of the colored phosphor is 10% by mass or more, color reproducibility and visible light transmittance can be further improved. However, if the content of the colored phosphor exceeds 65% by mass, the improvement in color reproducibility and visible light transmittance is saturated, which only increases the cost.

  The color correction layer 13 preferably contains a binder resin that binds the colored phosphor. As the binder resin, various thermoplastic resins and cured products of various thermosetting resins can be used.

(Transparent conductive sheet manufacturing method)
The transparent conductive sheet 10 a is formed by applying a conductive polymer solution to one surface of the transparent substrate 11 to form a transparent conductive layer 12, and applying a phosphor-containing solution to the other surface of the transparent substrate 11. It is obtained by forming the correction layer 13.
Here, the conductive polymer solution is a solution containing a π-conjugated conductive polymer, a polyanion, and a solvent.

[solvent]
The solvent used for the conductive polymer solution is water, but an organic solvent other than water may be included. Examples of the organic solvent include alcohols such as methanol, ethanol, propanol and butanol, carbonate compounds such as ethylene carbonate and propylene carbonate, phenols such as cresol, phenol and xylenol, ketones such as acetone and methyl ethyl ketone, hexane and benzene. , Hydrocarbons such as toluene, ether compounds such as dioxane, 2-methyltetrahydrofuran, diethyl ether, nitrile compounds such as acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile, N, N-dimethylformamide, N , N-dimethylacetamide, N-methyl-2-pyrrolidone, hexamethylene phosphortriamide, 1,3-dimethyl-2-imidazolidine, dimethylimidazole Down, ethyl acetate, dimethyl sulfoxide, sulfolane, and the like diphenyl sulfonic acid. These solvents may be used alone, as a mixture of two or more kinds, or as a mixture with other organic solvents.
Among the organic solvents, alcohols are preferable from the viewpoint of handleability.

[Neutralizer]
The conductive polymer solution preferably contains a neutralizing agent in order to further improve the conductivity of the transparent conductive layer 12 to be obtained.
Here, the neutralizing agent neutralizes the acidity of the polyanion and is, for example, an inorganic alkali or an organic alkali.
Examples of the inorganic alkali include sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia and the like.
Examples of the organic alkali include aliphatic amines, aromatic amines, quaternary amines, and metal alkoxides.

Examples of the aliphatic amine include ethylamine, propylamine, butylamine, hexylamine, octylamine, stearylamine, diethylamine, dipropylamine, dibutylamine, dioctylamine, methylethylamine, triethylamine, tripropylamine, tributylamine and the like. It is done.
Examples of the aromatic amine include aniline, benzylamine, pyrrole, pyridine and derivatives thereof, imidazole and derivatives thereof, pyrimidine and derivatives thereof, pyrazine and derivatives thereof, triazine and derivatives thereof, and the like. Of these, pyridine and derivatives thereof, imidazole and derivatives thereof, pyrimidine and derivatives thereof, pyrazine and derivatives thereof, triazine and derivatives thereof also function as conductivity improvers.
Examples of the quaternary amine include tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, and tetraoctylammonium hydroxide.
Examples of nitrogen-containing compounds other than amines include N-methyl-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, hexamethylene phosphortriamide, N-vinylpyrrolidone, N-vinylformamide, and N-vinyl. Examples include acetamide.
Examples of the metal alkoxide include sodium alkoxide such as sodium methoxide and sodium ethoxide, potassium alkoxide, calcium alkoxide and the like.
Among the neutralizing agents, organic alkalis composed of one or more components selected from the group consisting of aliphatic amines, aromatic amines, quaternary amines, and metal alkoxides are preferable because they can be easily neutralized.

  By containing the neutralizing agent, the conductive polymer solution is neutralized. Specifically, the pH (measured at 25 ° C.) of the conductive polymer solution is preferably 4 to 10, and more preferably 5 to 9. If the pH is less than 4, the corrosivity may be high. If it exceeds 10, the formation of the transparent conductive layer 12 becomes difficult, or the conductivity is lowered even if the transparent conductive layer 12 is formed. Sometimes.

As a method for applying the conductive polymer solution, for example, comma coating, reverse coating, lip coating, micro gravure coating, or the like is applied.
It is preferable to perform a curing treatment after the application of the conductive polymer solution.
As the curing method, heating or light irradiation is applied. As a heating method, for example, a normal method such as hot air heating or infrared heating can be employed. Moreover, when hardening by light irradiation, the method of irradiating an ultraviolet-ray from light sources, such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, can be employ | adopted, for example.

The phosphor-containing solution is a solution containing a colored phosphor and a solvent. As the solvent, the same solvents as those used in the conductive polymer solution can be used.
The phosphor-containing solution preferably contains a component that becomes a binder resin for binding the colored phosphor.
The component that becomes the binder resin may be a thermosetting resin or a thermoplastic resin. For example, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyimides; polyamide imides; polyamides such as polyamide 6, polyamide 6, 6, polyamide 12, and polyamide 11; polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene Fluoropolymers such as ethylene tetrafluoroethylene copolymer and polychlorotrifluoroethylene; vinyl resins such as polyvinyl alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl acetate, and polyvinyl chloride; epoxy resins; xylene resins; aramid resins; Polyurea; polyurea; melamine resin; phenol resin; polyether; acrylic resin and copolymers thereof.
The application method and the curing method of the phosphor-containing solution are the same as the application method and the curing method of the conductive polymer solution.

In the transparent conductive sheet 10a described above, even if the transmitted light is colored green to blue by the transparent conductive layer 12 including the π-conjugated conductive polymer, the color correction layer 13 including the colored phosphor can correct the color. Therefore, the color reproducibility is excellent. In addition, since the colored phosphor included in the color correction layer 13 is excited and emits light by incident light, sufficient visible light transmittance can be secured.
The transparent conductive sheet 10a can be applied to a resistive film type touch panel, a capacitance type touch panel, a transparent membrane switch, a transparent electromagnetic wave shield of a display, and the like.
In particular, the present invention can also be applied to portable devices with large power consumption restrictions and large screen displays that require high contrast.

  In addition, the transparent conductive sheet of this invention is not limited to the said embodiment example. For example, the transparent conductive layer may be formed on both surfaces of the transparent substrate. The color correction layer may also be formed on both sides of the transparent substrate. In that case, the color correction layer may be formed on the inner side or the outer side of the transparent conductive layer. However, when the transparent conductive sheet is used for a contact resistance touch panel, a transparent membrane switch, or the like, the color correction layer is not formed outside the transparent conductive layer. That is, in the transparent conductive sheet, the color correction layer is disposed between the substrate and the transparent conductive layer or on the surface of the substrate opposite to the transparent conductive layer.

  When using the transparent conductive sheet of this invention for an electrostatic capacitance type touch panel, as a structure of a transparent conductive sheet, for example, as shown in FIG. 2, a plurality of transparent substrates 11 and one surface of the transparent substrate 11 are provided. The first transparent conductive layer 12a, the second transparent conductive layer 12b provided on the other surface of the transparent substrate 11, and the surface of the second transparent conductive layer 12b opposite to the transparent substrate 11 A transparent conductive sheet 10b having a color correction layer 13 provided on the substrate can be used.

<Touch panel>
An embodiment of the touch panel of the present invention will be described.
FIG. 3 shows a touch panel according to this embodiment. This touch panel 1 is a resistive film type touch panel, and includes a movable electrode sheet 10 disposed on the input side and a fixed electrode sheet 20 disposed on the image display device side.
The movable electrode sheet 10 is the transparent conductive sheet 10a in which the transparent conductive layer 12 is provided on one side of the transparent substrate 11 and the color correction layer 13 is provided on the other side.
The fixed electrode sheet 20 is provided with a transparent conductive layer 22 on the surface of a transparent substrate 21.
The movable electrode sheet 10 and the fixed electrode sheet 20 are disposed so that the transparent conductive layers 12 and 22 face each other. A transparent dot spacer 30 is disposed between the movable electrode sheet 10 and the fixed electrode sheet 20 to form a gap.

Examples of the transparent base materials 11 and 21 of the movable electrode sheet 10 or the fixed electrode sheet 20 include a single layer or two or more layers of plastic films, glass plates, and laminates of films and glass plates. However, since the transparent base material 11 of the movable electrode sheet 10 has flexibility, a plastic film is preferable, and the transparent base material 21 of the fixed electrode sheet 20 is easy to fix, so glass, polycarbonate, Acrylic plates are preferred.
The transparent conductive layer 12 of the movable electrode sheet 10 is preferably a layer containing a π-conjugated conductive polymer and a polyanion because it is excellent in flexibility.
The transparent conductive layer 22 of the fixed electrode sheet 20 may be a layer containing ITO or a layer containing a π-conjugated conductive polymer and a polyanion.

The thickness of the transparent substrate 11 of the movable electrode sheet 10 is preferably 100 to 250 μm. If the thickness of the transparent substrate 11 is 100 μm or more, sufficient strength can be secured, and if it is 250 μm or less, sufficient flexibility can be secured.
The thickness of the transparent conductive layer 12 of the movable electrode sheet 10 is preferably 50 to 700 μm. If the thickness of the transparent substrate 11 is 50 μm or more, sufficient conductivity can be secured, and if it is 700 μm or less, sufficient flexibility and transparency can be secured.
The thickness of the transparent substrate 21 of the fixed electrode sheet 20 is preferably 0.8 to 2.5 mm. If the thickness of the transparent substrate 11 is 0.8 mm or more, sufficient strength can be ensured, and if it is 2.5 mm or less, the thickness can be reduced and space saving can be realized.
The thickness of the transparent conductive layer 22 of the fixed electrode sheet 20 is preferably 0.01 to 1.0 μm. If the thickness of the transparent conductive layer 22 is 0.01 μm or more, sufficient conductivity can be ensured, and if it is 1.0 μm or less, the thickness can be reduced and space saving can be realized.
It is preferable that the space | interval at the time of the non-pressing of the movable electrode sheet 10 and the fixed electrode sheet 20 is 20-100 micrometers. If the distance between the movable electrode sheet 10 and the fixed electrode sheet 20 when not pressed is 20 μm or more, the movable electrode sheet 10 and the fixed electrode sheet 20 can be reliably prevented from contacting each other when not pressed, and the distance is 100 μm or less. If it exists, the movable electrode sheet 10 and the fixed electrode sheet 20 can be reliably brought into contact at the time of pressing. In order to achieve the interval, the size of the dot spacer 30 may be selected as appropriate.

In this resistive touch panel, when the movable electrode sheet 10 is pressed with a finger or a stylus, the transparent conductive layer 12 of the movable electrode sheet 10 and the transparent conductive layer 22 of the fixed electrode sheet 20 are brought into contact with each other to conduct electricity. The voltage is taken in and the position is detected.
In such a resistive touch panel, since the movable electrode sheet 10 having the color correction layer 13 including the colored phosphor is used, the color reproducibility is excellent and the visible light transmittance is high.

  The touch panel of the present invention is provided in, for example, an electronic notebook, a personal digital assistant (PDA), a mobile phone, a PHS, an automatic teller machine (ATM), a vending machine, a point-of-sale information management (POS) register, and the like.

Examples of the present invention will be specifically described below, but the present invention is not limited to the examples.
(Production Example 1) Preparation of polystyrene sulfonic acid 206 g of sodium styrene sulfonate was dissolved in 1000 ml of ion-exchanged water, and 1.14 g of ammonium persulfate oxidizing agent solution previously dissolved in 10 ml of water was stirred at 80 ° C. The solution was added dropwise for 20 minutes, and the solution was stirred for 2 hours.
1000 ml and 10,000 ml of ion-exchanged water diluted with 10% by mass of sulfuric acid diluted to 10% by mass were added to the sodium styrenesulfonate-containing solution thus obtained, and about 10,000 ml of the polystyrenesulfonic acid-containing solution was removed using an ultrafiltration method. Then, 10,000 ml of ion-exchanged water was added to the remaining liquid, and about 10,000 ml of solution was removed using an ultrafiltration method. The above ultrafiltration operation was repeated three times.
Furthermore, about 10,000 ml of ion-exchanged water was added to the obtained filtrate, and about 10,000 ml of solution was removed using an ultrafiltration method. This ultrafiltration operation was repeated three times.
The ultrafiltration conditions were as follows (the same applies to other examples).
Molecular weight cut off of ultrafiltration membrane: 30000
Cross flow type Supply liquid flow rate: 3000 ml / min Membrane partial pressure: 0.12 Pa
Water in the obtained solution was removed under reduced pressure to obtain colorless solid polystyrene sulfonic acid.

(Production Example 2) Preparation of Polystyrenesulfonic Acid Doped Poly (3,4-ethylenedioxythiophene) Aqueous Solution 14.2 g of 3,4-ethylenedioxythiophene and 36.7 g of polystyrenesulfonic acid obtained in Production Example 1 A solution dissolved in 2000 ml of ion-exchanged water was mixed at 20 ° C.
While maintaining the mixed solution thus obtained at 20 ° C. and stirring, 29.64 g of ammonium persulfate dissolved in 200 ml of ion exchange water and 8.0 g of ferric sulfate oxidation catalyst solution were slowly added, The reaction was stirred for 3 hours.
2000 ml of ion-exchanged water was added to the resulting reaction solution, and about 2000 ml of solution was removed using an ultrafiltration method. This operation was repeated three times.
Then, 200 ml of sulfuric acid diluted to 10% by mass and 2000 ml of ion-exchanged water are added to the treatment liquid that has been subjected to the filtration treatment, and about 2000 ml of the treatment liquid is removed using an ultrafiltration method. Ion exchange water was added and about 2000 ml of liquid was removed using ultrafiltration. This operation was repeated three times.
Furthermore, 2000 ml of ion-exchanged water was added to the obtained treatment liquid, and about 2000 ml of the treatment liquid was removed using an ultrafiltration method. This operation was repeated 5 times to obtain an about 1.5% by mass blue polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene) (PEDOT-PSS) aqueous solution.

(Production Example 3) Preparation of Conductive Polymer Solution To 600 g of the PEDOT-PSS aqueous solution obtained in Production Example 2, 20.1 g of imidazole (2 molar equivalents relative to the polyanion) was added and stirred to contain imidazole. A PEDOT-PSS aqueous solution was prepared.
Separately, 3.6 g of 2,3,3 ′, 4,4 ′, 5′-hexahydroxybenzophenone, 0.9 g of Irgacure 127 (manufactured by Ciba Specialty Chemicals), 18 g of 2-hydroxyethylacrylamide, penta 7.2 g of erythritol triacrylate, 300 g of ethanol, tin-doped indium oxide (manufactured by Sumitomo Metal Mining Co., Ltd .; X500 series, average particle size: 100-140 nm) 0.3 g (total of π-conjugated conductive polymer and polyanion 4.1% by mass with respect to 100% by mass) was added and stirred. A PEDOT-PSS aqueous solution containing the imidazole was added to the solution thus obtained and stirred to obtain a conductive polymer solution A.

(Production Example 4) Production of YAG-based phosphor Yttrium, gadolinium, and cerium were dissolved in acid at a stoichiometric ratio, and the resulting solution was coprecipitated with oxalic acid, and then fired at a firing temperature of 1600 ° C. A precipitated oxide was obtained. Next, this coprecipitated oxide was mixed with aluminum oxide, and ammonium fluoride was further mixed as a flux, and the resulting mixture was filled in a crucible. Subsequently, it baked for 3 hours at 1400 degreeC in air atmosphere, and the baked product was obtained. Next, the fired product was pulverized in water with a ball mill, washed, separated, dried, and sieved to obtain a YAG phosphor.
This phosphor was an oxide (Y _0.8 Gd _0.2 ) 3Al ₅ O ₁₂ : Ce in which about 20% of yttrium was replaced with gadolinium. The cerium substitution was 0.03.

(Production Example 5) Preparation of phosphor-containing solution Components shown in Table 1 were mixed to prepare a phosphor-containing solution.

Example 1
The conductive polymer solution A was applied to one side of a polyethylene terephthalate film (A4300 manufactured by Toyobo Co., Ltd., thickness: 188 μm) with a reverse coater, dried at 100 ° C. for 2 minutes by infrared irradiation, and then irradiated with ultraviolet light (high pressure mercury lamp 120 W, 360 mJ / cm ² , 178 mW / cm ² ) irradiation and curing to form a transparent conductive layer.
Further, the phosphor-containing solution obtained in Production Example 5 was applied to the other surface of the polyethylene terephthalate film with a reverse coater, dried at 100 ° C. for 2 minutes by infrared irradiation, and then irradiated with ultraviolet rays (high pressure mercury lamp 120W, 360 mJ / cm ² , 178 mW / cm ² ) and cured to form a color correction layer. Thereby, a transparent conductive sheet was obtained.
The obtained transparent conductive sheet was left in an oven at 150 ° C. for 30 minutes, and then the visible light transmittance was measured according to JIS K7136 using a Nippon Denshoku Industries Co., Ltd. haze meter measuring device (NDH5000). Moreover, the color tone was observed visually. The surface resistance was measured according to JIS K 7194 using a Loresta MCP-T600 manufactured by Mitsubishi Chemical Corporation.
As a result, the visible light transmittance was 86.3%, the color tone was light blue, and the surface resistance was 780Ω.

(Comparative Example 1)
A transparent conductive sheet was obtained in the same manner as in Example 1 except that the color correction layer was not formed. When evaluated in the same manner as in Example 1, the visible light transmittance was 85.3%, the color tone was light gray, and the surface resistance was 780Ω. Further, white turbidity was observed in the transparent conductive sheet.

(Example 2)
A conductive paste (FAr-401CA manufactured by Fujikura Kasei Co., Ltd.) is screen-printed on the edge of the long side of the transparent conductive layer 12 of the transparent conductive sheet obtained in Example 1, and dried to form electrodes 14a having a length of 90 mm and a spacing of 80 mm. , 14b are formed to obtain the movable electrode sheet 10 (see FIG. 4) on the input side.
Similarly, the conductive paste (Far-401CA manufactured by Fujikura Kasei Co., Ltd.) is screen-printed on the short edge of the transparent conductive layer 22 of the transparent conductive sheet obtained in Comparative Example 1 and dried to obtain a length of 80 mm. Electrodes 23a and 23b with a spacing of 90 mm were formed. Further, a dot spacer paste (SN-8400C manufactured by Fujikura Kasei Co., Ltd.) was screen-printed, dried, and irradiated with ultraviolet rays to form dot spacers 30. Thereby, the fixed electrode sheet 20 (see FIG. 5) for the image display device was obtained. Next, the movable electrode sheet 10 and the fixed electrode sheet 20 were fixed at the periphery using a double-sided tape, and the resistive touch panel was attached. Obtained.
Then, as shown in FIG. 6, a constant current 31 is connected to the touch panel, and while drawing with a polyacetal stylus 35 having a tip of 0.8 R, the voltage between the electrodes of the movable electrode sheet 10 and the electrodes of the fixed electrode sheet The voltage was measured by the voltage measuring means 34a and 34b. As a result, it was operating normally as a touch panel.
The visible light transmittance of this touch panel was 73.2%, and it was a slightly bluish gray color. Moreover, although the white turbidity was slightly seen in the fixed electrode sheet, the white turbidity was not visible when viewed through the movable electrode sheet.

(Comparative Example 2)
A resistive touch panel was obtained in the same manner as in Example 2 except that the transparent conductive sheet of Comparative Example 1 was used as the movable electrode sheet 10.
This touch panel had a visible light transmittance of 73.2% and a slightly bluish color tone. Further, a slight cloudiness was observed on the movable electrode sheet.

DESCRIPTION OF SYMBOLS 10 Movable electrode sheet 10a, 10b Transparent conductive sheet 11, 21 Transparent base material 12, 12a, 12b, 22 Transparent conductive layer 13 Color correction layer 20 Fixed electrode sheet 30 Dot spacer

Claims (3)

  Having a transparent substrate, at least one transparent conductive layer containing a π-conjugated conductive polymer and a polyanion, and a color correction layer containing a colored phosphor complementary to the color of the transparent conductive layer A transparent conductive sheet characterized by the above.   The transparent conductive sheet according to claim 1, wherein the color correction layer is disposed between the transparent substrate and the transparent conductive layer or on the surface of the transparent substrate opposite to the transparent conductive layer. In a touch panel comprising a pair of transparent conductive sheets having a transparent base material and a transparent conductive layer containing a π-conjugated conductive polymer and a polyanion, and arranged so that the transparent conductive layers of each transparent conductive sheet face each other ,
The touch panel, wherein at least one transparent conductive sheet is the transparent conductive sheet according to claim 2.

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