JP2017054506A - Light-transmitting conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-transmitting conductive film in which a pattern of a conductive layer is not easily recognized visually and white scattering does not occur easily.SOLUTION: A light-transmitting conductive film 1 relating to the present invention is a film having light-transmitting property as well as conductivity, and includes a light-transmitting substrate 2 having a first surface 2a and a second surface 2b opposing to the first surface 2a, a light-transmitting conductive layer 3 disposed on the first surface 2a side of the substrate film 2, and a hard coat layer 4 disposed on the second surface 2b side of the substrate film 2. The hard coat layer 4 has a resin part 7 and a filler 8, in which an absolute difference between the refractive index in the resin part 7 and the refractive index in the filler 8 is 0.08 or more, and an average particle diameter of the filler 8 is smaller than the thickness of the hard coat layer 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light transmissive conductive film having light transparency and conductivity.

  In recent years, touch panel liquid crystal display devices have been widely used in electronic devices such as smartphones, mobile phones, notebook computers, tablet PCs, copiers, and car navigation systems. In such a liquid crystal display device, a light transmissive conductive film in which a transparent conductive layer is laminated on a base film is used. The transparent conductive layer is usually used after being heat-treated. In order to prevent the base film from shrinking during the heat treatment, a cured resin layer called a hard coat layer is provided on the surface of the base film.

  Patent Document 1 below discloses a transparent conductive film in which a hard coat layer is laminated on the surface of one side of a substrate and a conductive layer is laminated on the surface of the other side. In Patent Document 1, fingerprint-proof processing is performed on the surface of the hard coat layer opposite to the substrate side. Patent Document 1 describes that the anti-fingerprint treatment is a treatment in which fine particles are added to a resin constituting the hard coat layer.

  Moreover, the following patent document 2 describes a transparent conductive film including a transparent film substrate, a transparent conductive thin film, and a hard coat layer. Patent Document 2 describes that the hard coat layer may contain inorganic oxide particles having an average particle size of 200 nm or less.

Japanese Patent No. 4464449 Japanese Patent No. 5693066

  When a conductive film containing fine particles on the surface of the hard coat layer is used in a liquid crystal display device as in Patent Document 1, there is a problem that white light scattering occurs and display light becomes difficult to see (problem of white blur).

  Moreover, the electrode used for a liquid crystal display device is formed by patterning a conductive layer, and the reflection intensity by external light differs between a portion where the conductive layer is present and a portion where the conductive layer is not present. Therefore, there is a problem that the pattern of the conductive layer is visually recognized (problem of bone appearance). In particular, as in Patent Document 2, there is a tendency that a problem is remarkably generated in a conductive film in which a hard coat layer includes inorganic oxide particles having a small average particle diameter.

  An object of the present invention is to provide a light-transmitting conductive film in which a pattern of a conductive layer is hardly visible and white scattering is hardly generated.

  The light transmissive conductive film according to the present invention is a light transmissive and conductive film, and includes a first surface and a second surface facing the first surface. And a light-transmitting base film, a conductive layer that is disposed on the first surface side of the base film and has light transmittance, and a second surface side of the base film An absolute value of a difference between a refractive index of the resin portion of the hard coat layer and a refractive index of the filler. However, the average particle diameter of the filler is smaller than the thickness of the hard coat layer.

  On the specific situation with the transparent electroconductive film which concerns on this invention, ratio with respect to the thickness of the said hard-coat layer of the average particle diameter of the said filler exceeds 1/2 and is less than 1.

  In a specific aspect of the light transmissive conductive film according to the present invention, the filler does not protrude on the surface of the hard coat layer.

  On the specific situation with the transparent electroconductive film which concerns on this invention, the absolute value of the difference of the refractive index of the said resin part and the refractive index of the said filler is less than 0.3.

  On the specific situation with the transparent electroconductive film which concerns on this invention, the average particle diameter of the said filler is 0.2 micrometer or more and 3.0 micrometers or less.

  On the specific situation with the transparent electroconductive film which concerns on this invention, the said filler is a filler containing an organic component at least.

  The light-transmitting conductive film according to the present invention is suitably used for a liquid crystal display device.

  The light-transmitting conductive film according to the present invention includes a light-transmitting base film, a light-transmitting conductive layer disposed on the first surface side of the base film, and the base film. A hard coat layer disposed on the second surface side, the hard coat layer includes a filler and a resin portion, and an absolute value of a difference between the refractive index of the resin portion and the refractive index of the filler is 0. Since the average particle diameter of the filler is smaller than the thickness of the hard coat layer, the pattern of the conductive layer is difficult to be visually recognized and white scattering hardly occurs. Therefore, the light transmissive conductive film of the present invention is excellent in reliability.

Fig.1 (a) is typical sectional drawing which shows the light transmissive conductive film which concerns on one Embodiment of this invention, FIG.1 (b) expands and shows the hard-coat layer of Fig.1 (a). It is a typical fragmentary sectional view. FIG. 2 is a schematic cross-sectional view showing a modification of the light transmissive conductive film according to one embodiment of the present invention.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

  Fig.1 (a) is typical sectional drawing which shows the light transmissive conductive film which concerns on one Embodiment of this invention, FIG.1 (b) expands and shows the hard-coat layer of Fig.1 (a). It is a typical fragmentary sectional view. In FIG. 1, the length, width, thickness, shape, and amount of filler of each layer and filler are appropriately changed from the actual size and shape for convenience of illustration.

  The light-transmitting conductive film 1 shown in FIGS. 1A and 1B includes a base film 2, a conductive layer 3, first and second hard coat layers 4 and 5, and an undercoat layer 6. Prepare. The light transmissive conductive film 1 is a film having light transparency and conductivity.

  The base film 2 is made of a material having high light transmittance. The base film 2 has a first surface 2a and a second surface 2b. The first surface 2a and the second surface 2b are opposed to each other. On the 1st surface 2a, the 2nd hard-coat layer 5, the undercoat layer 6, and the conductive layer 3 are arrange | positioned and laminated | stacked in this order. The first surface 2a is a surface on the side where the conductive layer 3 is disposed.

  On the second surface 2b of the base film 2, the first hard coat layer 4 is disposed and laminated. The second surface 2b is a surface on the side where the first hard coat layer 4 is disposed.

  The conductive layer 3 is made of a material having high light transmittance and high conductivity. The conductive layer 3 is partially laminated on the surface of the undercoat layer 6. The light transmissive conductive film 1 has a portion with the conductive layer 3 and a portion without the conductive layer 3 on the surface of the undercoat layer 6. Note that the conductive layer 3 may be directly laminated on the first surface 2 a of the base film 2.

  The first hard coat layer 4 includes a resin portion 7 and a filler 8. The resin portion 7 is a portion excluding the filler 8 in the first hard coat layer 4. The resin part 7 is made of a binder resin. By providing the first hard coat layer 4, it is possible to suppress warpage of the base film 2 caused by the heat treatment of the conductive layer described in the column of the manufacturing method described later. Moreover, the surface of the base film 2 can be protected by providing the first hard coat layer 4.

  The filler 8 is disposed inside the first hard coat layer 4. The filler 8 is disposed so that the surface of the first hard coat layer 4 does not protrude by the filler 8. The filler 8 does not protrude on the surface of the first hard coat layer 4. On the surface of the first hard coat layer 4, no protruding portion due to the filler 8 is formed. The first hard coat layer 4 does not have a protruding portion in which the filler 8 protrudes from the surface. Therefore, the surface of the first hard coat layer 4 is smooth, and the light transmissive conductive film 1 hardly causes white scattering.

  In the first hard coat layer 4, the absolute value of the difference between the refractive index of the resin portion 7 and the refractive index of the filler 8 is 0.08 or more. Therefore, the light incident on the first hard coat layer 4 can be irregularly reflected, and the pattern of the conductive layer 3 can be made difficult to be visually recognized (illusion effect).

  The absolute value of the difference between the refractive index of the resin portion 7 and the refractive index of the filler 8 is preferably less than 0.3. When the difference in refractive index between the resin portion 7 and the filler 8 is less than the above upper limit, white scattering can be further suppressed. In addition, the refractive index of the resin part 7 and the filler 8 can be measured with a refractometer such as an Abbe refractometer or a Karnew precision refractometer (manufactured by Shimadzu Corporation).

  The absolute value of the difference between the refractive index of the resin portion 7 of the first hard coat layer 4 and the refractive index of the filler 8 from the viewpoint of making the pattern of the conductive layer 3 less visible and further suppressing white scattering. Is more preferably 0.10 or more, preferably 0.19 or less, and more preferably 0.15 or less.

  The average particle diameter of the filler 8 is smaller than the thickness of the first hard coat layer 4. Therefore, white scattering hardly occurs in the light transmissive conductive film 1. The average particle diameter means an average volume particle diameter, and can be measured by a laser diffraction / scattering particle diameter distribution measuring apparatus. In Examples described later, the average volume particle size was measured with a particle size distribution measuring device (manufactured by Horiba, Ltd., product number: LA-950).

  The second hard coat layer 5 is made of a resin. By providing the second hard coat layer 5, it is possible to further suppress the warp of the base film 2 caused by the heat treatment of the conductive layer 3. Moreover, the surface of the base film 2 can be protected by providing the second hard coat layer 5.

Undercoat layer 6 is constituted by SiO _2. By providing the undercoat layer 6, the difference in refractive index between the conductive layer 3 and the second hard coat layer 5 can be reduced. Therefore, the light transmittance of the light transmissive conductive film 1 can be further enhanced.

  FIG. 2 is a schematic cross-sectional view showing a modification of the light transmissive conductive film according to one embodiment of the present invention.

  As shown in FIG. 2, in the light transmissive conductive film 1 </ b> A of the modification, the second hard coat layer is not provided. In the light transmissive conductive film 1A, the undercoat layer 6A and the conductive layer 3A are arranged and laminated in this order on the first surface 2a of the base film 2A.

  In the light-transmitting conductive film of the present invention, the second hard coat layer may not be provided as in the present modification. Further, both the second hard coat layer and the undercoat layer may not be provided. On the 1st surface of a base film, the undercoat layer and the conductive layer may be laminated | stacked in this order, and the conductive layer may be laminated | stacked directly. The undercoat layer may be a single layer or a multilayer.

  Since the light-transmitting conductive films of the present invention such as the light-transmitting conductive film 1 and the light-transmitting conductive film 1A have the above-described configuration, the pattern of the conductive layer is hardly visible and suppresses white scattering. be able to. Therefore, in the light-transmitting conductive film of the present invention, the problem of bone appearance and the problem of white blur are unlikely to occur. Therefore, the light transmissive conductive film of the present invention is excellent in reliability.

  Since the light-transmitting conductive film of the present invention is difficult to visually recognize the pattern of the conductive layer and can suppress white scattering, when used in a liquid crystal display device, the visibility of display light can be improved. Therefore, the light transmissive conductive film of the present invention can be suitably used for a liquid crystal display device.

  In particular, in the touch panel, when the pattern of the conductive layer is visually recognized and white scattering occurs, the display quality and usability are greatly adversely affected. Since the pattern of the conductive layer is hardly visible and white scattering can be suppressed, the light-transmitting conductive film of the present invention can be suitably used for a liquid crystal display device, and can be suitably used for a touch panel.

  Hereinafter, other details of the light-transmitting conductive film according to the present invention will be described.

(Base film)
The base film preferably has high light transmittance. Accordingly, the material of the base film is not particularly limited. For example, polyolefin, polyethersulfone, polysulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene Examples thereof include phthalate, triacetyl cellulose, and cellulose nanofiber. The base film is preferably formed of a resin. The said base film may be used independently and may use multiple.

  Although the thickness of a base film is not specifically limited, It is preferable that it is 5 micrometers or more, It is more preferable that it is 20 micrometers or more, It is preferable that it is 188 micrometers or less, It is more preferable that it is 125 micrometers or less. When the thickness of the base film is not less than the above lower limit and not more than the above upper limit, the pattern of the conductive layer can be made even less visible.

  Moreover, as for the light transmittance of a base film, it is preferable that the average transmittance | permeability in the visible light region with a wavelength of 380-780 nm is 85% or more, and it is more preferable that it is 90% or more.

  The refractive index of the base film is preferably 1.40 or more, more preferably 1.50 or more, preferably 1.70 or less, and more preferably 1.60 or less. When the refractive index of the base film is not less than the above lower limit and not more than the above upper limit, the pattern of the conductive layer can be made more difficult to be visually recognized.

  Moreover, the base film may contain various stabilizers, ultraviolet absorbers, plasticizers, lubricants, or colorants.

(Conductive layer)
The conductive layer is made of a light-transmitting conductive material. As the conductive material is not particularly limited, for example, IZO (indium zinc oxide) or, In-based oxides such as ITO (indium tin _oxide), Sn, such as SnO 2, FTO (fluorine-doped tin oxide) Oxide, AZO (aluminum zinc oxide), Zn oxide such as GZO (gallium zinc oxide), sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum - lithium alloy, Al / _Al 2 _{O 3} mixture, Al / LiF mixture, a metal such as gold, CuI, Ag nanowire (AgNW), such as carbon nanotubes (CNT) or conductive transparent polymers. The said electroconductive material may be used independently and may use multiple together.

From the viewpoint of further increasing the conductivity and further increasing the light transmittance, the conductive material is selected from In-based oxides such as IZO (indium zinc oxide) and ITO (indium tin oxide), SnO ₂ , FTO. Sn-based oxides such as (fluorine-doped tin oxide), Zn-based oxides such as AZO (aluminum zinc oxide) and GZO (gallium zinc oxide) are preferable, and ITO (indium tin oxide) is preferable. Is more preferable.

  Although the thickness of a conductive layer is not specifically limited, It is preferable that it is 12 nm or more, It is more preferable that it is 17 nm or more, It is preferable that it is 50 nm or less, It is more preferable that it is 30 nm or less.

  When the thickness of a conductive layer is more than the said minimum, the electroconductivity of a transparent conductive film can be improved further. When the thickness of the conductive layer is not more than the above upper limit, the pattern of the conductive layer can be made more difficult to be visually recognized, and the thickness can be further reduced.

  Further, the light transmittance of the conductive layer is preferably 85% or more, more preferably 90% or more, in the visible light region.

(First hard coat layer)
The first hard coat layer is composed of a resin portion and a filler.

  The thickness of the first hard coat layer is preferably 1 μm or more, more preferably 1.5 μm or more, preferably 4 μm or less, and more preferably 3 μm or less. By setting the thickness of the first hard coat layer to the above lower limit or more and the above upper limit or less, the pattern of the conductive layer can be made more difficult to be visually recognized, and white scattering can be further suppressed.

Resin part;
The resin part of the first hard coat layer can be composed of a binder resin. The binder resin is preferably a cured resin. As the curable resin, a thermosetting resin, an active energy ray curable resin, or the like can be used. From the viewpoint of improving productivity and economy, the curable resin is preferably an ultraviolet curable resin.

  Examples of the photocurable monomer for forming the ultraviolet curable resin include 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, and tetraethylene glycol diacrylate. , Tripropylene glycol diacrylate, neopentyl glycol diacrylate, 1,4-butanediol dimethacrylate, poly (butanediol) diacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, triethylene glycol diacrylate Such as triisopropylene glycol diacrylate, polyethylene glycol diacrylate and bisphenol A dimethacrylate Triacrylate compounds such as trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol monohydroxytriacrylate and trimethylolpropane triethoxytriacrylate; of pentaerythritol tetraacrylate and di-trimethylolpropane tetraacrylate And tetraacrylate compounds such as dipentaerythritol (monohydroxy) pentaacrylate. As the ultraviolet curable resin, a polyfunctional acrylate having 5 or more functional groups may be used. The said polyfunctional acrylate may be used independently and may use multiple together. Moreover, you may add a photoinitiator, a photosensitizer, a leveling agent, a diluent, etc. to the said polyfunctional acrylate compound.

Fillers;
Although it does not specifically limit as a filler, For example, metal oxides, such as a silica, iron oxide, aluminum oxide, zinc oxide, titanium oxide, silicon dioxide, antimony oxide, a zirconium oxide, a tin oxide, cerium oxide, an indium tin oxide Particles; Alternatively, resin particles mainly composed of silicone, (meth) acryl, styrene, melamine, olefin, or the like can be used. More specifically, vinyl polymer particles such as crosslinked poly (meth) methyl acrylate can be used. The said filler may be used independently and may use multiple together.

  From the viewpoint of further increasing the difference in refractive index from the resin portion and making the pattern of the conductive layer more difficult to visually recognize, the filler is preferably an organic filler, and more preferably resin particles. In addition, inorganic-organic composite particles containing an organic component can also be suitably used.

  The filler may be hollow particles containing air or bubbles inside. Examples of the hollow particles include hollow silica and mesoporous silica.

  Although depending on the refractive index of the resin part, the refractive index of the filler is preferably 1.50 or more, more preferably 1.55 or more, further preferably 1.60 or more. It is preferably 90 or less, and more preferably 1.70 or less.

  By setting the refractive index of the filler within the above range, the refractive index difference with the resin portion can be increased, and the pattern of the conductive layer can be made more difficult to visually recognize.

  In 100% by weight of the first hard coat layer, the filler content is preferably 0.01% by weight or more, more preferably 0.03% by weight or more, and 0.05% by weight or more. It is preferably 1% by weight or less, more preferably 0.5% by weight or less, and further preferably 0.3% by weight or less.

  When content of a filler is more than the said minimum, it can make it difficult to visually recognize the pattern of a conductive layer. When the filler content is not more than the above upper limit, white scattering can be further suppressed.

  The average particle diameter of the filler is smaller than the thickness of the first hard coat layer. The ratio of the average particle diameter of the filler to the thickness of the first hard coat layer (the average particle diameter of the filler / the thickness of the first hard coat layer) is preferably more than 1/2, and preferably less than 1. . When the said ratio exceeds the said minimum and is less than the said upper limit, the pattern of a conductive layer can be made harder to visually recognize and white scattering can be suppressed further. From the viewpoint of making the pattern of the conductive layer less visible and further suppressing white scattering, the ratio is preferably 0.6 or more, and more preferably 0.9 or less.

  The average particle diameter of the filler is preferably 0.2 μm or more, preferably 0.3 μm or more, more preferably 0.4 μm or more, and further preferably 1.0 μm or more. It is preferably 0.0 μm or less, more preferably 2.0 μm or less, and even more preferably 1.5 μm or less.

  When the average particle diameter of a filler is more than the said minimum, it can make it difficult to visually recognize the pattern of a conductive layer. When the average particle diameter of the filler is not more than the above upper limit, white scattering can be further suppressed.

A second hard coat layer;
The second hard coat layer is made of a binder resin and has a resin portion. The binder resin is preferably a cured resin. As the curable resin, a thermosetting resin, an active energy ray curable resin, or the like can be used. From the viewpoint of productivity and economy, the curable resin is preferably an ultraviolet curable resin.

  Examples of the photocurable monomer for forming the ultraviolet curable resin include 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, and tetraethylene glycol diacrylate. , Tripropylene glycol diacrylate, neopentyl glycol diacrylate, 1,4-butanediol dimethacrylate, poly (butanediol) diacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, triethylene glycol diacrylate Such as triisopropylene glycol diacrylate, polyethylene glycol diacrylate and bisphenol A dimethacrylate Triacrylate compounds such as trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol monohydroxytriacrylate and trimethylolpropane triethoxytriacrylate; of pentaerythritol tetraacrylate and di-trimethylolpropane tetraacrylate And tetraacrylate compounds such as dipentaerythritol (monohydroxy) pentaacrylate. As the ultraviolet curable resin, a polyfunctional acrylate having 5 or more functional groups may be used. The said polyfunctional acrylate may be used independently and may use multiple together. Moreover, you may add a photoinitiator, a photosensitizer, a leveling agent, a diluent, etc. to the said polyfunctional acrylate compound.

Undercoat layer;
The undercoat layer is, for example, a refractive index adjustment layer. By providing the undercoat layer, the difference in refractive index between the conductive layer and the second hard coat layer or the base film can be reduced, so that the light transmissive conductive film can be further improved in light transmittance. Can be increased.

The material constituting the undercoat layer is not particularly limited as long as it has a refractive index adjustment function, inorganic materials such as SiO ₂ , MgF ₂ , Al ₂ O ₃ , acrylic resins, urethane resins, melamine resins, alkyd resins, Organic materials such as siloxane polymers can be mentioned.

  The undercoat layer can be formed by a vacuum deposition method, a sputtering method, an ion plating method, or a coating method.

(Production method)
The manufacturing method of a light transmissive conductive film is not specifically limited. As a manufacturing method of a light transmissive conductive film, the following methods are mentioned, for example.

  First, a first hard coat layer is formed on one surface side of the base film. Specifically, when an ultraviolet curable resin is used as the resin, first, a photocurable monomer, a photoinitiator, and a filler are stirred in a diluent to prepare a coating liquid. The obtained coating liquid is applied onto a substrate film, and the resin is cured by irradiating with ultraviolet rays to produce a first hard coat layer.

  Next, when providing a 2nd hard-coat layer, a 2nd hard-coat layer is formed on the surface of the other side of a base film. Specifically, when an ultraviolet curable resin is used as the resin, first, a photocurable monomer and a photoinitiator are stirred in a diluent to prepare a coating solution. The obtained coating liquid is applied onto a base film, and the resin is cured by irradiating ultraviolet rays to form a second hard coat layer.

Subsequently, when an undercoat layer is provided, an undercoat layer is formed on the second hard coat layer. Specifically, when SiO ₂ is used, an undercoat layer can be formed on the second hard coat layer by vapor deposition or sputtering.

  Next, a conductive layer is formed on the undercoat layer. The method for forming the conductive layer is not particularly limited. For example, a method of etching a metal film formed by vapor deposition or sputtering, various printing methods such as screen printing or inkjet printing, and a known patterning method such as a photolithography method using a resist can be used. The formed conductive layer can be used with its crystallinity increased by heat treatment.

  Hereinafter, the present invention will be described in more detail based on specific examples. The present invention is not limited to the following examples.

Example 1
Forming a first hard coat layer;
100 parts by weight of urethane acrylate oligomer as a photocurable monomer, 140 parts by weight of a mixed solvent of toluene and methyl isobutyl ketone (MIBK) as a diluent solvent, and 5 weights of Irgacure 194 (manufactured by Ciba Specialty Chemicals) as a photoinitiator Part and 0.1 parts by weight of vinyl polymer particles (manufactured by Sekisui Plastics Co., Ltd., trade name: Techpolymer, refractive index 1.58, average particle size: 1.2 μm) as a filler, A first coating solution was prepared.

The first coating solution was applied on the surface of one side of a 50 μm thick PET film and dried. After drying, the resin was cured by irradiating UV light of 200 mJ / cm ^{2 with} a high pressure mercury lamp to form a first hard coat layer having a thickness of 2.0 μm.

Formation of a second hard coat layer;
100 parts by weight of urethane acrylate oligomer as a photocurable monomer, 160 parts by weight of a mixed solvent of toluene and methyl isobutyl ketone (MIBK) as a diluting solvent, and 5 parts by weight of Irgacure 194 (manufactured by Ciba Specialty Chemicals) as a photoinitiator Part and 100 parts by weight of zirconia particles (average particle size 30 nm) were mixed and stirred to prepare a second coating solution.

The second coating liquid was applied on the surface of the PET film opposite to the first hard coat layer side and dried. After drying, the resin was cured by irradiating UV light of 200 mJ / cm ^{2 with} a high-pressure mercury lamp to form a second hard coat layer having a thickness of 1.0 μm.

Formation of an undercoat layer;
SiO ₂ was deposited on the second hard coat layer to form an undercoat layer having a thickness of 20 nm.

Forming a conductive layer;
An ITO layer (conductive layer) having a thickness of 18 nm was deposited on the undercoat layer. A dry film resist was applied to the PET film on which the ITO layer was deposited, and exposure and development were performed. Subsequently, etching, peeling, washing, and drying steps were performed in this order, and the ITO layer was patterned to obtain a light-transmitting conductive film.

  In addition, the refractive index of the filler and resin part which comprise the 1st hard-coat layer of a transparent conductive film was measured based on JISK7142. The filler was measured by an immersion method using a microscope in accordance with JIS K 7142 method B. Moreover, about the resin part, the film | membrane remove | excluding the filler from the 1st hard-coat layer was formed, and it measured using the Abbe refractometer based on A method of JISK7142.

(Examples 2-6 and Comparative Examples 1-5)
By changing the type of filler of the first hard coat layer, the refractive index of the filler and the average particle diameter of the filler were set as shown in Table 1 below, and the thickness of the first hard coat layer was changed as follows. A light-transmitting conductive film was obtained in the same manner as in Example 1 except that the setting was as in 1.

  In Examples 2 to 6 and Comparative Examples 1 to 5, the following fillers were used, respectively.

Example 2: Vinyl polymer-based particles (manufactured by Sekisui Plastics Co., Ltd., trade name: Techpolymer, refractive index: 1.58, average particle size: 1.5 μm)
Example 3: Styrene / zirconia mixed filler (vinyl polymer / zirconia mixed filler, manufactured by Sekisui Plastics Co., Ltd., trade name: Techpolymer, refractive index: 1.68, average particle size: 2.0 μm)
Example 4: Hollow silica (manufactured by JGC Catalysts & Chemicals, trade name: thruria, refractive index: 1.30, average particle size: 0.05 μm)
Example 5: Styrene / zirconia mixed filler (vinyl polymer / zirconia mixed filler, manufactured by Sekisui Plastics Co., Ltd., trade name: Techpolymer, refractive index: 1.68, average particle size: 2.0 μm) was crushed with a ball mill. -By classification, particles having a refractive index of 1.68 and an average particle size of 0.3 μm were obtained.
Example 6: Vinyl polymer particles (manufactured by Sekisui Plastics Co., Ltd., trade name: Techpolymer, refractive index 1.58, average particle size: 1.2 μm)

Comparative Example 1: Vinyl polymer-based particles (manufactured by Sekisui Plastics Co., Ltd., trade name: Techpolymer, refractive index: 1.58, average particle size: 1.2 μm)
Comparative Example 2: Silica particles (manufactured by Admatechs, trade name: Admafine, refractive index: 1.46, average particle size: 1.5 μm)
Comparative Example 3: Styrene / zirconia mixed filler (vinyl polymer / zirconia mixed filler, manufactured by Sekisui Plastics Co., Ltd., trade name: Techpolymer, refractive index: 1.68, average particle size: 2.0 μm)
Comparative Example 4: Silica particles (manufactured by Admatechs, trade name: Admafine, refractive index 1.46, average particle size: 1.5 μm)
Comparative Example 5: PMMA-based particles (manufactured by Sekisui Plastics Co., Ltd., trade name: SSX-101, refractive index 1.49, average particle size: 1.0 μm)

<Evaluation>
The following evaluation was performed about the light transmissive conductive film obtained in Examples 1-6 and Comparative Examples 1-5. The results are shown in Table 1 below.

(1) Evaluation of bone appearance About the obtained light-transmitting conductive film, bone appearance was evaluated according to the following criteria.

OO: The pattern of the conductive layer is not visually recognized when irradiated with any of LED light, fluorescent light, and white light.
◯: When the LED light is irradiated, the conductive layer pattern is visually recognized. However, when either the fluorescent lamp or the white lamp is irradiated, the conductive layer pattern is not visually recognized.
○: When the LED light and the fluorescent lamp are irradiated, the conductive layer pattern is visually recognized. However, when the white lamp is irradiated, the conductive layer pattern is not visually recognized.
X: The conductive layer pattern is visually recognized when any of the LED light, the fluorescent lamp, and the white lamp is irradiated.

(2) Evaluation of graininess (evaluation of white blur)
The obtained light transmissive conductive film was irradiated with a fluorescent lamp, and the graininess was evaluated (evaluation of white blur) according to the following criteria.

OO: A fluorescent lamp is reflected on the surface of the light transmissive conductive film.
○: The surface of the light-transmitting conductive film is slightly white and blurred.
X: The surface of the light-transmitting conductive film is blurred in white.

DESCRIPTION OF SYMBOLS 1,1A ... Light-transmissive conductive film 2, 2A ... Base film 2a ... 1st surface 2b ... 2nd surface 3, 3A ... Conductive layer 4 ... 1st hard-coat layer 5 ... 2nd hard-coat layer 6, 6A ... Undercoat layer 7 ... Resin part 8 ... Filler

Claims (7)

A film having optical transparency and conductivity,
A base film having a first surface and a second surface facing the first surface and having light transparency;
A conductive layer disposed on the first surface side of the base film and having light transparency;
A hard coat layer disposed on the second surface side of the base film,
The hard coat layer has a resin part and a filler,
The absolute value of the difference between the refractive index of the resin part of the hard coat layer and the refractive index of the filler is 0.08 or more,
The light-transmitting conductive film, wherein an average particle size of the filler is smaller than a thickness of the hard coat layer.   2. The light-transmissive conductive film according to claim 1, wherein a ratio of an average particle diameter of the filler to a thickness of the hard coat layer is more than ½ and less than 1. 3.   The light-transmitting conductive film according to claim 1 or 2, wherein the filler does not protrude on the surface of the hard coat layer.   The light-transmitting conductive film according to any one of claims 1 to 3, wherein an absolute value of a difference between a refractive index of the resin portion and a refractive index of the filler is less than 0.3.   The light-transmitting conductive film according to claim 1, wherein the filler has an average particle size of 0.2 μm or more and 3.0 μm or less.   The light-transmissive conductive film according to claim 1, wherein the filler is a filler containing at least an organic component.   The light-transmitting conductive film according to claim 1, which is used for a liquid crystal display device.

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