KR102547456B1 - Transparent conductive film and image display device - Google Patents

Abstract

A transparent conductive film is provided with a 1st transparent conductive layer, a 1st optical adjustment layer, a transparent base material, a 2nd optical adjustment layer, and a 2nd transparent conductive layer in order. The surface resistance value of the second transparent conductive layer is greater than the surface resistance value of the first transparent conductive layer, the surface resistance value of the first transparent conductive layer is 10 Ω/□ or more and 70 Ω/□ or less, and the second transparent The surface resistance value of the conductive layer is 50 Ω/□ or more and 150 Ω/□ or less, and the refractive index of the second optical adjustment layer is lower than the refractive index of the first optical adjustment layer.

Description

Transparent conductive film and image display device

The present invention relates to a transparent conductive film and an image display device including the same.

Conventionally, it is known that an image display device including a touch panel and an image display element includes a film for a touch panel in which a transparent conductive layer made of indium tin composite oxide (ITO) is formed on a transparent substrate. As such a film for a touch panel, a double-sided transparent conductive film in which ITO layers are arranged on both sides of a transparent substrate is described in Patent Literature 1, for example.

By the way, since image display elements such as liquid crystal cells generate electromagnetic waves, an electromagnetic wave shielding effect for shielding electromagnetic waves is desired for image display devices. In a resistive touch panel, it is known that an ITO structure in which two ITO films are disposed to face each other has an electromagnetic shielding effect (for example, see Non-Patent Document 1).

In particular, in Non-Patent Document 1, it is described that in order to lower the resistance value of the ITO film, the ITO film must be thickened, and as a result, the light transmittance decreases. Further, it is described that when the resistance value of only one ITO film (for example, about 10 Ω) is lowered, even if the resistance value of the other ITO film is increased, a good electromagnetic shielding effect is obtained.

And, from these results, Non-Patent Document 1 shows that, by lowering the resistance value of only one ITO film and increasing the resistance value of the other ITO film, it is possible to suppress the decrease in light transmittance while expressing a good electromagnetic shielding effect. are starting

Japanese Unexamined Patent Publication No. 2013-99924

Nozomu Harada, 「Effect of Electromagnetic Shielding of Resistive Touch Panel Sensors」, E, Vol. 128, No. 7, 2008, p.312-313

However, in a touch panel film (double-sided transparent conductive film) used in a capacitive type with good durability and less malfunction, two ITO layers disposed on both sides are etched into an electrode pattern shape. And in order to suppress visibility of an electrode pattern, an optical adjustment layer is formed between the ITO layer and a transparent base material.

In this case, since the double-sided transparent conductive film further includes an optical adjusting layer, the light transmittance is lowered.

The present invention provides a transparent conductive film and an image display device having an electromagnetic shielding effect, suppressing visibility of an electrode pattern, and having good light transmittance.

The present invention [1] is provided with a first transparent conductive layer, a first optical adjustment layer, a transparent base material, a second optical adjustment layer and a second transparent conductive layer in order, the surface resistance value of the second transparent conductive layer, The surface resistance value of the first transparent conductive layer is greater than the surface resistance value of the first transparent conductive layer, the surface resistance value of the first transparent conductive layer is 10 Ω/□ or more and 70 Ω/□ or less, and the surface resistance value of the second transparent conductive layer is, 50 Ω/□ or more and 150 Ω/□ or less, and the refractive index of the second optical adjusting layer is smaller than the refractive index of the first optical adjusting layer, and includes a transparent conductive film.

This invention [2] includes the transparent conductive film described in [1], wherein the thickness of the second transparent conductive layer is smaller than the thickness of the first transparent conductive layer.

In the present invention [3], the refractive index of the first optical adjusting layer is 1.65 or more and 1.75 or less, and the refractive index of the second optical adjusting layer is 1.60 or more and 1.70 or less, the transparent conductive film according to [1] or [2]. contains

The present invention [4] includes the transparent conductive film according to any one of [1] to [3], characterized in that both the first optical adjustment layer and the second optical adjustment layer have a thickness of 100 nm or less. are doing

In the present invention [5], both the first transparent conductive layer and the second transparent conductive layer are patterned, the first transparent conductive layer has a first pattern elongated in one direction, and the second transparent conductive layer is patterned. The layer is provided with a second pattern that is long in an orthogonal direction orthogonal to the one direction, and the length of the first pattern in one direction is longer than the length of the second pattern in the orthogonal direction, any one of [1] to [4] The transparent conductive film according to one item is included.

The present invention [6] is an image display device comprising the transparent conductive film according to any one of [1] to [5], and an image display element arranged on the first transparent conductive layer side of the transparent conductive film. contains

According to the transparent conductive film of the present invention, a first transparent conductive layer, a first optical adjustment layer, a transparent substrate, a second optical adjustment layer and a second transparent conductive layer are sequentially provided. Therefore, when the first transparent conductive layer and the second transparent conductive layer are patterned, visibility of the first transparent conductive layer and the second transparent conductive layer can be suppressed.

In addition, since the surface resistance value of the first transparent conductive layer is 10 Ω/□ or more and 70 Ω/□ or less, the transparent conductive film includes a transparent conductive layer having a small surface resistance value. Therefore, the transparent conductive film can exhibit a favorable electromagnetic shielding effect.

In addition, since the surface resistance value of the second transparent conductive layer is larger than that of the first transparent conductive layer and is 50 Ω/□ or more and 150 Ω/□ or less, the second transparent conductive layer is used as the first transparent conductive layer. It can be relatively thin than the layer. Moreover, the refractive index of the 2nd optical adjustment layer is lower than the refractive index of the 1st optical adjustment layer. By these, the light transmittance of the transparent conductive film can be improved.

ADVANTAGE OF THE INVENTION The image display apparatus of this invention has an electromagnetic wave shielding effect, suppresses visibility of the patterned 1st transparent conductive layer and the 2nd transparent conductive layer, and has favorable light transmittance.

1 shows a cross-sectional view of one embodiment of the transparent conductive film of the present invention.
FIG. 2 is a cross-sectional view of a film for a touch panel obtained by patterning the transparent conductive film shown in FIG. 1 .
3A to 3B are a film for a touch panel shown in FIG. 2 , in which FIG. 3A is a plan view showing the electrode pattern of the first transparent conductive layer, and FIG. 3B is a bottom view showing the electrode pattern of the second transparent conductive layer. indicate
FIG. 4 shows an image display device provided with the transparent conductive film shown in FIG. 2 .
5A to 5B are modified examples of the touch panel film of the present invention (a form in which the electrode pattern of the transparent conductive layer has a plurality of continuous rectangular patterns), and FIG. 5A shows the electrode of the first transparent conductive layer A plan view showing the pattern, Fig. 5B shows a bottom view showing the electrode pattern of the second transparent conductive layer.

<One Embodiment of Transparent Conductive Film>

An embodiment of the transparent conductive film of the present invention will be described below with reference to the drawings. In Fig. 1, the vertical direction of the paper is the vertical direction (thickness direction, first direction), the upper side of the paper is the upper side (one side in the thickness direction, one side in the first direction), and the lower side of the paper is the lower side (the other side in the thickness direction, the first direction). the other side of the direction). In addition, the left-right direction of the paper is a left-right direction (a second direction, an orthogonal direction orthogonal to the first direction), the left side of the paper is the left (one side of the second direction), and the right side of the paper is the right (the other side of the second direction). In addition, the paper thickness direction is in the depth direction (the third direction, the orthogonal direction orthogonal to the first and second directions), the front side of the paper is the front (one side of the third direction), and the inner side of the paper is the rear (third direction). the other side of the direction). Specifically, it is based on the direction arrows in each drawing.

1. Transparent conductive film

The transparent conductive film 1 has a film shape (including sheet shape) with a predetermined thickness, extends in a predetermined direction (surface direction) orthogonal to the thickness direction, and has a flat upper surface and a flat lower surface. The transparent conductive film 1 is one component for producing a base material for a touch panel or the like provided in an image display device, for example, and is not, in short, an image display device. That is, the transparent conductive film 1 is a device that can be used industrially by being distributed as a single component without including an image display element such as a liquid crystal cell.

Specifically, as shown in FIG. 1 , the transparent conductive film 1 includes a transparent substrate 2, a first hard coat layer 3 disposed on the upper surface (one side) of the transparent substrate 2, and 1 1st optical adjustment layer 4 arrange|positioned on the upper surface of the hard coat layer 3, the 1st transparent conductive layer 5 arrange|positioned on the upper surface of the 1st optical adjustment layer 4, and transparent base material 2 The second hard coat layer 6 disposed on the lower surface (the other side) of the second hard coat layer 6, the second optical adjustment layer 7 disposed on the lower surface of the second hard coat layer 6, and the second optical adjustment layer 7 It is provided with the 2nd transparent conductive layer 8 arrange|positioned on the lower surface. That is, the transparent conductive film 1 is, in order from the bottom, the second transparent conductive layer 8, the second optical adjustment layer 7, the second hard coat layer 6, the transparent substrate 2, and the first hard coat. A layer (3), a first optical adjustment layer (4), and a first transparent conductive layer (5) are provided.

The transparent conductive film 1 preferably includes the second transparent conductive layer 8, the second optical adjustment layer 7, the second hard coat layer 6, the transparent substrate 2, and the first hard coat layer ( 3), the first optical adjustment layer 4 and the first transparent conductive layer 5. Hereinafter, each layer is explained in detail.

(transparent substrate)

The transparent substrate 2 is a substrate that secures the mechanical strength of the transparent conductive film 1 . The transparent substrate 2 includes the first transparent conductive layer 5 and the second transparent conductive layer 8, the first hard coat layer 3, the second hard coat layer 6, and the first optical adjustment layer ( 4) and the second optical adjustment layer 7 are supported together.

The transparent substrate 2 is, for example, a polymer film having transparency. Examples of the material for the polymer film include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, and (meth)acrylic resins such as polymethacrylate (acrylic resins). and/or methacrylic resin), e.g., olefin resins such as polyethylene, polypropylene, cycloolefin polymer (COP), etc., e.g., polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, poly Amide resin, polyimide resin, cellulose resin, polystyrene resin, norbornene resin, etc. are mentioned. A polymer film can be used individually or in combination of 2 or more types.

From the viewpoints of transparency, heat resistance, mechanical strength and the like, olefin resins are preferred, and COP is more preferred.

The thickness of the transparent substrate 2 is, for example, 2 μm or more, preferably 20 μm or more, from the viewpoints of mechanical strength, scratch resistance, spot characteristics of the film 1a for a touch panel, etc., and, for example, 300 μm or less, preferably 150 μm or less.

The thickness of the transparent substrate 2 can be measured using, for example, a microgauge type thickness meter.

Moreover, an easily bonding layer, an adhesive bond layer, etc. may be formed in the upper surface and/or lower surface of the transparent base material 2 as needed.

(1st hard coat layer)

The first hard coat layer 3 is a scratch protection layer for making the transparent conductive film 1 less prone to scratches.

The 1st hard-coat layer 3 has a film shape, and is arrange|positioned so that it may contact the upper surface of the transparent base material 2 on the whole upper surface of the transparent base material 2, for example. More specifically, the first hard coat layer 3 is between the transparent substrate 2 and the first optical adjustment layer 4, the upper surface of the transparent substrate 2 and the lower surface of the first optical adjustment layer 4 placed in contact with

The 1st hard-coat layer 3 is formed, for example from a hard-coat composition.

The hard-coat composition of the 1st hard-coat layer 3 contains resin, Preferably it consists only of resin.

Examples of the resin include curable resins and thermoplastic resins (eg polyolefin resins), and curable resins are preferred.

Examples of the curable resin include active energy ray-curable resins that are cured by irradiation with active energy rays (specifically, ultraviolet rays, electron beams, etc.), for example, thermosetting resins that are cured by heating, and the like; Preferably, an active energy ray-curable resin is used.

Examples of the active energy ray-curable resin include a polymer having a functional group having a polymerizable carbon-carbon double bond in the molecule. As such a functional group, a vinyl group, a (meth)acryloyl group (methacryloyl group and/or acryloyl group), etc. are mentioned, for example.

As an active energy ray-curable resin, (meth)acrylic-type ultraviolet curable resin, such as urethane acrylate and epoxy acrylate, is mentioned specifically, for example.

Moreover, as curable resins other than active energy ray-curable resin, thermosetting resins, such as a urethane resin, a melamine resin, an alkyd resin, a siloxane type polymer, and an organic silane condensate, are mentioned, for example.

Resin can be used alone or in combination of two or more.

The hard coat composition may contain particles. Thereby, the 1st hard-coat layer 3 can be made into an anti-blocking layer with anti-blocking characteristics.

Examples of the particles include inorganic particles and organic particles. Examples of the inorganic particles include silica particles, metal oxide particles made of zirconium oxide, titanium oxide, zinc oxide, and tin oxide, and carbonate particles such as calcium carbonate. Examples of the organic particles include crosslinked acrylic resin particles and the like. Particles can be used alone or in combination of two or more.

Moreover, well-known additives, such as a leveling agent, a thixotropic agent, and an antistatic agent, can be further contained in a hard-coat composition.

The refractive index of the first hard coat layer 3 is, for example, 1.40 or more, preferably 1.45 or more, and, for example, less than 1.60, preferably 1.55 or less. When the first hard coat layer 3 is within the above range, the refractive index of the first hard coat layer 3 can be lowered than the refractive index of the first optical adjusting layer 4, and visibility of the electrode pattern can be further suppressed. there is.

The refractive index of the hard-coat layer (the 1st hard-coat layer 3 and the 2nd hard-coat layer 6) can be measured using a spectroscopic ellipsometer, for example.

The thickness of the first hard coat layer 3 is, for example, 0.1 μm or more, preferably 0.5 μm or more, and, for example, 10 μm or less, preferably from the viewpoint of scratch resistance and visibility of the electrode pattern. is 5 μm or less.

The thickness of the hard code layer (first hard coat layer 3 and second hard coat layer 6) was determined based on the waveform of the interference spectrum using an instantaneous multi-photometry system ("MCPD2000" manufactured by Otsuka Electronics Co., Ltd.) can be calculated

(1st optical adjustment layer)

The first optical adjustment layer 4 is used to secure excellent transparency of the transparent conductive film 1 while suppressing visibility of the pattern (e.g. electrode pattern) when the first transparent conductive layer 5 is patterned. For this purpose, it is a layer that adjusts the optical properties (eg refractive index) of the transparent conductive film 1.

The 1st optical adjustment layer 4 has a film shape, and is arrange|positioned so that it may contact the upper surface of the 1st hard-coat layer 3 on the whole upper surface of the 1st hard-coat layer 3, for example. More specifically, the first optical adjustment layer 4 is between the first hard coat layer 3 and the first transparent conductive layer 5, the upper surface of the first hard coat layer 3 and the first transparent conductive layer It is arranged so as to contact the lower surface of the layer (5).

The 1st optical adjustment layer 4 is formed from the optical adjustment composition.

An optical adjustment composition contains resin, for example. The optical adjusting composition preferably contains resin and particles, and more preferably consists only of resin and particles.

Although it does not specifically limit as resin, The same thing as resin used for a hard-coat composition is mentioned. Resin can be used alone or in combination of two or more. A curable resin is preferred, and an active energy ray curable resin is more preferred.

The content of the resin is, for example, 10% by mass or more, preferably 25% by mass or more, and, for example, 95% by mass or less, preferably 60% by mass or less, relative to the optical adjusting composition.

As the particles, a suitable material can be selected according to the refractive index required of the first optical adjusting layer 4, and examples thereof include inorganic particles and organic particles. Examples of the inorganic particles include silica particles, such as zirconium oxide, titanium oxide, zinc oxide, and metal oxide particles made of oxide, such as carbonate particles such as calcium carbonate. Examples of the organic particles include crosslinked acrylic resin particles and the like. Particles can be used alone or in combination of two or more.

As the particles, inorganic particles are preferably used, metal oxide particles are more preferable, and zirconium oxide particles (ZnO ₂ ) are still more preferable.

The average particle diameter (median diameter) of the particles is, for example, 10 nm or more, preferably 20 nm or more, and, for example, 100 nm or less, preferably 50 nm or less.

The content of the particles is, for example, 5% by mass or more, preferably 40% by mass or more, and, for example, 90% by mass or less, preferably 75% by mass or less, relative to the optical adjusting composition.

The refractive index of the 1st optical adjustment layer 4 is higher than the refractive index of the 2nd optical adjustment layer 7, eg 1.65 or more, Preferably it is 1.70 or more. Moreover, about an upper limit, it is 1.80 or less, for example, Preferably it is 1.75 or less. When the refractive index of the first optical adjusting layer 4 is within the above range, the light transmittance of the transparent conductive film 1 can be further improved.

The refractive indices of the optical adjustment layers (the first optical adjustment layer 4 and the second optical adjustment layer 7) can be measured using a spectroscopic ellipsometer, for example.

The thickness of the first optical adjusting layer 4 is, for example, 150 nm or less, preferably 100 nm or less, more preferably 85 nm or less, and, for example, 10 nm or more, preferably 20 nm or more. am. When the thickness of the first optical adjustment layer 4 is equal to or less than the above upper limit, the color of the transparent conductive film 1 (in particular, the color space of La*b*) can be made more reliably neutral. That is, the coloration (for example, yellow) of the transparent conductive film 1 can be reduced, and the colorless and transparent transparent conductive film 1 can be reliably obtained.

The thickness of the optical adjustment layer (the first optical adjustment layer 4 and the second optical adjustment layer 7) can be measured using, for example, an instantaneous multi-photometry system ("MCPD2000" manufactured by Otsuka Electronics Co., Ltd.), and the waveform of the interference spectrum. can be calculated based on

(1st transparent conductive layer)

The first transparent conductive layer 5 is a transparent conductive layer for forming into a predetermined pattern (for example, an electrode pattern) in a post process such as etching.

The first transparent conductive layer 5 is the uppermost layer of the transparent conductive film 1, has a film shape, and is formed on the entire upper surface of the first optical adjustment layer 4 and on the upper surface of the first optical adjustment layer 4. placed in contact.

As a material of the 1st transparent conductive layer 5, it is selected from the group which consists of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W, for example. and metal oxides containing at least one type of metal. The metal oxide may be further doped with metal atoms shown in the above groups as needed.

The material of the first transparent conductive layer 5 is preferably an indium-containing oxide such as indium-tin composite oxide (ITO), for example, an antimony-containing oxide such as antimony-tin composite oxide (ATO). , More preferably, an indium-containing oxide is used, and still more preferably, ITO is used. Thereby, the 1st transparent conductive layer 5 can achieve both excellent transparency and electroconductivity.

When ITO is used as the material of the first transparent conductive layer 5, the content of tin oxide (SnO ₂ ) is, for example, 0.5% by mass or more with respect to the total amount of tin oxide and indium oxide (In ₂ O ₃ ); Preferably it is 3 mass % or more, and, for example, 15 mass % or less, Preferably it is 13 mass % or less.

"ITO" should just be a composite oxide containing at least indium (In) and tin (Sn), and may contain additional components other than these. Examples of additional components include metal elements other than In and Sn, specifically Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W, and Fe. , Pb, Ni, Nb, Cr, Ga and the like.

The first transparent conductive layer 5 may be either crystalline or amorphous. The first transparent conductive layer 5 is preferably made of crystalline, more specifically a crystalline ITO layer. Thereby, the transparency of the 1st transparent conductive layer 5 can be improved and the surface resistance value of the 1st transparent conductive layer 5 can further be reduced.

The transparent conductive layer (the first transparent conductive layer 5 and the second transparent conductive layer 8) is crystalline, for example, when the transparent conductive layer is an ITO layer, in hydrochloric acid (concentration: 5% by mass) at 20 ° C. After being immersed for 15 minutes, it is washed with water and dried, and it can be judged by measuring the resistance between terminals between about 15 mm. Specifically, when the resistance between terminals between 15 mm is 10 kΩ or less after being immersed in hydrochloric acid (20°C, concentration: 5% by mass), washed with water, and dried, the ITO layer is assumed to be crystalline.

The surface resistance value of the 1st transparent conductive layer 5 is lower than the surface resistance value of the 2nd transparent conductive layer 8, Specifically, it is 10 ohm/square or more and 70 ohm/square or less. It is preferably 20 Ω/□ or more, more preferably 30 Ω/□ or more, and is preferably 60 Ω/□ or less, more preferably 50 Ω/□ or less. When the surface resistance value of the first transparent conductive layer 5 is within the above range, the transparent conductive film 1 can exhibit excellent electromagnetic shielding properties and conductivity.

The surface resistance value of the transparent conductive layers (the first transparent conductive layer 5 and the second transparent conductive layer 8) can be measured, for example, using a four-terminal method.

The thickness of the first transparent conductive layer 5 is preferably thicker than the thickness of the second transparent conductive layer 8, for example, 30 nm or more, preferably 35 nm or more, and, for example, 200 nm or less, preferably 100 nm or less, more preferably 60 nm or less. When the thickness of the first transparent conductive layer 5 is within the above range, the electromagnetic shielding properties of the transparent conductive film 1 can be further improved.

The thickness of the transparent conductive layers (the first transparent conductive layer 5 and the second transparent conductive layer 8) can be measured, for example, by observing a cross section of the transparent conductive layer with a transmission electron microscope (TEM).

(2nd hard coat layer)

The second hard coat layer 6 is a scratch protection layer for making the transparent conductive film 1 less prone to scratches.

The 2nd hard-coat layer 6 has a film shape, and is arrange|positioned so that it may contact the lower surface of the transparent base material 2 on the whole surface of the lower surface of the transparent base material 2, for example. More specifically, the second hard coat layer 6 is between the transparent substrate 2 and the second optical adjustment layer 7, the lower surface of the transparent substrate 2 and the upper surface of the second optical adjustment layer 7 placed in contact with

The 2nd hard-coat layer 6 is the same layer as the 1st hard-coat layer 3, and has the same structure (thickness, refractive index, etc.) from the same material as the 1st hard-coat layer 3, for example. Then, the 2nd hard-coat layer 6 also has the same shape and the same dimensions as the 1st hard-coat layer 3.

(Second optical adjustment layer)

The second optical adjustment layer 7 is used to secure excellent transparency of the transparent conductive film 1 while suppressing visibility of the pattern (for example, electrode pattern) when the second transparent conductive layer 8 is patterned. For this purpose, it is a layer that adjusts the optical properties (eg refractive index) of the transparent conductive film 1.

The 2nd optical adjustment layer 7 has a film shape, and is arrange|positioned so that it may contact the lower surface of the 2nd hard-coat layer 6 on the whole surface of the lower surface of the 2nd hard-coat layer 6, for example. More specifically, the second optical adjustment layer 7 is between the second hard coat layer 6 and the second transparent conductive layer 8, the lower surface of the second hard coat layer 6 and the second transparent conductive layer It is placed in contact with the upper surface of layer (8).

The 2nd optical adjustment layer 7 is formed from the optical adjustment composition. As an optical adjustment composition, the thing similar to what was mentioned above for the 1st optical adjustment layer 4 is mentioned.

The refractive index of the second optical adjustment layer 7 is lower than the refractive index of the first optical adjustment layer 4, for example, 1.70 or less, preferably less than 1.65, and more preferably 1.64 or less. Moreover, about a lower limit, it is 1.55 or more, for example, Preferably it is 1.60 or more. When the refractive index of the second optical adjustment layer 7 is within the above range, the light transmittance of the transparent conductive film 1 can be further improved.

The difference in refractive index between the second optical adjusting layer 7 and the first optical adjusting layer 4 is, for example, 0.01 or more, preferably 0.05 or more, and, for example, 0.20 or less, preferably 0.15 or less. . When the difference in refractive index is within the above range, the transmittance of the transparent conductive film 1 can be improved or the color can be neutralized.

The thickness of the second optical adjustment layer 7 is, for example, 150 nm or less, preferably 100 nm or less, more preferably 85 nm or less, and, for example, 10 nm or more, preferably 20 nm or more. am. If the thickness of the second optical adjustment layer 7 is equal to or less than the above upper limit, the color tone can be made more reliably neutral.

(Second transparent conductive layer)

The second transparent conductive layer 8 is a transparent conductive layer for forming into a predetermined pattern (for example, an electrode pattern) in a post process such as etching.

The second transparent conductive layer 8 is the lowermost layer of the transparent conductive film 1, has a film shape, and is formed on the entire surface of the lower surface of the second optical adjustment layer 7 and the lower surface of the second optical adjustment layer 7. placed in contact.

As a material constituting the second transparent conductive layer 8, the same materials as those described above for the first transparent conductive layer 5 can be used. Preferably it is ITO. The second transparent conductive layer 8 may be either crystalline or amorphous, but is preferably crystalline, and more specifically, is a crystalline ITO layer.

The surface resistance value of the 2nd transparent conductive layer 8 is higher than the surface resistance value of the 1st transparent conductive layer 5, Specifically, it is 50 ohm/square or more and 150 ohm/square or less. It is preferably 60 Ω/□ or more, more preferably 70 Ω/□ or more, still more preferably 100 Ω/□ or more, and preferably 120 Ω/□ or less. When the surface resistance value of the second transparent conductive layer 8 is within the above range, the thickness of the second transparent conductive layer 8 can be reduced, and the light transmittance of the transparent conductive film 1 can be improved.

The difference in surface resistance between the first transparent conductive layer 5 and the second transparent conductive layer 8 is, for example, 10 Ω/□ or more, preferably 20 Ω/□ or more, more preferably 40 Ω/□ or more. It is □ or more, and, for example, 100 Ω/□ or less, preferably 70 Ω/□ or less.

The thickness of the second transparent conductive layer 8 is preferably smaller than the thickness of the first transparent conductive layer 5, for example, 35 nm or less, preferably 30 nm or less, and, for example, 1 nm or more, preferably 10 nm or more. When the thickness of the second transparent conductive layer 8 is within the above range, the light transmittance of the transparent conductive film 1 can be further improved.

2. Manufacturing method of transparent conductive film

In order to manufacture the transparent conductive film 1, first, the transparent base material 2 is prepared, and then, on both sides of the transparent base material 2, a hard coat layer (the first hard coat layer 3 and the second hard coat layer) is applied. (6)), optical adjustment layer (first optical adjustment layer (4) and second optical adjustment layer (7)) and transparent conductive layer (first transparent conductive layer (5) and second transparent conductive layer (8)) form in turn.

For example, first, the dilution liquid which diluted the hard-coat composition which forms the 1st hard-coat layer 3 or the 2nd hard-coat layer 6 with a solvent is prepared. Subsequently, the diluted solution is applied to the upper or lower surface of the transparent substrate 2, and each diluted solution is dried to cure the hard coat composition as needed. Thereby, the 1st hard-coat layer 3 is formed on the upper surface of the transparent base material 2, and the 2nd hard-coat layer 6 is formed on the lower surface of the transparent base material 2.

Next, the dilution liquid which diluted the optical adjustment composition which forms the 1st optical adjustment layer 4 or the 2nd optical adjustment layer 7 with the solvent is prepared. Subsequently, the dilution liquid is applied to the upper surface of the first hard coat layer 3 or the lower surface of the second hard coat layer 6, each dilution liquid is dried, and the optical adjusting composition is cured as necessary. Thereby, the 1st optical adjustment layer 4 is formed on the upper surface of the 1st hard-coat layer 3, and the 2nd optical adjustment layer 7 is formed on the lower surface of the 2nd hard-coat layer 6. That is, a laminate of the second optical adjustment layer (7)/second hard coat layer (6)/transparent substrate (2)/first hard coat layer (3)/first optical adjustment layer (4) is obtained.

Next, the first transparent conductive layer 5 and the second transparent conductive layer 8 are sequentially formed on both surfaces of the laminate by a dry method.

As a dry method, a vacuum deposition method, a sputtering method, an ion plating method, etc. are mentioned, for example. A sputtering method is preferred. A thin transparent conductive layer can be formed by this method.

Examples of the sputtering method include a two-pole sputtering method, an ECR (electron cyclotron resonance) sputtering method, a magnetron sputtering method, and an ion beam sputtering method. Preferably, a magnetron sputtering method is used.

When employing the sputtering method, as a target material, the above-mentioned metal oxide which comprises a transparent conductive layer, etc. are mentioned, Preferably ITO is mentioned. The tin oxide concentration of ITO is, for example, 0.5% by mass or more, preferably 3% by mass or more, and, for example, 15% by mass or less, preferably 13% by mass, from the viewpoint of durability of the ITO layer, crystallization, etc. less than %.

As a gas, an inert gas, such as Ar, is mentioned, for example. In addition, a reactive gas such as oxygen gas may be used in combination as needed. When using a reactive gas together, the flow rate ratio (sccm) of the reactive gas is not particularly limited, but is, for example, 0.1 flow% or more and 5 flow% or less with respect to the total flow rate ratio of the sputter gas and the reactive gas.

The atmospheric pressure during sputtering is, for example, 1 Pa or less, and preferably 0.1 Pa or more and 0.7 Pa or less, from the viewpoint of suppressing a decrease in the sputtering rate and discharge stability.

The power supply may be any of, for example, a DC power supply, an AC power supply, an MF power supply, and an RF power supply, or a combination thereof.

At this time, the surface resistance value of each transparent conductive layer can be adjusted by separately adjusting the thickness of the 1st transparent conductive layer 5 and the 2nd transparent conductive layer 8 formed in a laminated body, respectively, for example. . That is, the surface resistance value can be made low by making the thickness of a transparent conductive layer thick, and the surface resistance value can be made high by conversely making the thickness of a transparent conductive layer thin. In this invention, formation of each transparent conductive layer is adjusted so that the thickness of the 2nd transparent conductive layer 8 may become thinner than the thickness of the 1st transparent conductive layer 5 preferably.

Thus, the second transparent conductive layer 8, the second optical adjustment layer 7, the second hard coat layer 6, the transparent substrate 2, the first hard coat layer 3, the first optical adjustment layer ( 4) and the transparent conductive film 1 equipped with the 1st transparent conductive layer 5 in this order are obtained.

If necessary, then, the transparent conductive film 1 is subjected to heat treatment in air.

The heat treatment can be performed using, for example, an infrared heater or an oven.

The heating temperature is, for example, 100°C or higher, preferably 120°C or higher, and, for example, 200°C or lower, preferably 160°C or lower.

The heating time is appropriately determined depending on the heating temperature, and is, for example, 10 minutes or more, preferably 30 minutes or more, and, for example, 5 hours or less, preferably 3 hours or less.

By this heat treatment, each transparent conductive layer can be crystallized, and a desired surface resistance value can be obtained.

In addition, in this manufacturing method, each layer can be formed with respect to the transparent base material 2 by a roll-to-roll system, for example, or some or all of these layers can be formed by a batch system (sheet system). there is.

The light transmittance (visibility average transmittance) of the transparent conductive film 1 is, for example, 86.0% or more, preferably 86.5% or more. When the light transmittance is within the above range, the transparent conductive film 1 can be surely obtained.

The color La* of the transparent conductive film 1 is, for example, -1.5 or more, preferably -1.0 or more, and, for example, is preferably 1.5 or less, preferably 0.5 or less. Hue Lb* is, for example, -4.0 or more, preferably -0.5 or more, and, for example, is preferably 4.0 or less, preferably 1.0 or less. When the color is within the above range, the colorless and transparent transparent conductive film 1 can be surely obtained.

This transparent conductive film 1 can be used as a film for touch panels, such as an optical method, an ultrasonic method, a capacitance method, or a resistive film method, for example. In particular, it can be preferably used as a film for a touch panel of a capacitive type (specifically, a projection type capacitance type).

3. Film for touch panel

Next, the film 1a for a touch panel, which is an embodiment of the transparent conductive film 1, will be described.

As shown in FIG. 2, the film 1a for touch panels consists of a transparent base material 2, a first hard coat layer 3 disposed on the upper surface of the transparent base material 2, and a first hard coat layer 3 ) disposed on the upper surface of the first optical adjustment layer 4, the patterning first transparent conductive layer 5a disposed on the upper surface of the first optical adjustment layer 4, and disposed on the lower surface of the transparent substrate 2 The second hard coat layer 6, the second optical adjustment layer 7 disposed on the lower surface of the second hard coat layer 6, and the patterning second transparent disposed on the lower surface of the second optical adjustment layer 7 A conductive layer (8a) is provided. That is, the transparent conductive film 1 is sequentially patterned from the bottom: the second transparent conductive layer 8a, the second optical adjustment layer 7, the second hard coat layer 6, the transparent substrate 2, the first hard It is provided with the coat layer 3, the 1st optical adjustment layer 4, and the patterning 1st transparent conductive layer 5a. The film 1a for touch panels, Preferably the patterning 2nd transparent conductive layer 8a, the 2nd optical adjustment layer 7, the 2nd hard coat layer 6, the transparent base material 2, the 1st hard coat It consists of a layer (3), a first optical adjustment layer (4) and a patterned first transparent conductive layer (5a).

As shown in FIGS. 3A and 3B , the film 1a for touch panels has a substantially rectangular shape in planar view that is long in the left-right direction (one direction, long side direction) and short in the front-back direction (other direction, short side direction). have

The film 1a for touch panels is patterned transparent obtained by patterning (patterning) the transparent conductive layers (the first transparent conductive layer 5 and the second transparent conductive layer 8) of the transparent conductive film 1 described above. It is a conductive film. Therefore, the 2nd optical adjustment layer 7 of the film 1a for touch panels, the 2nd hard coat layer 6, the transparent base material 2, the 1st hard coat layer 3, and the 1st optical adjustment layer 4 ) is the same as each layer of the transparent conductive film 1 described above.

As shown in FIG. 3A , the patterning first transparent conductive layer 5a is provided with a first rectangular pattern 11 elongated in the left-right direction as an example of the first pattern at a substantially central portion in plan view. . Specifically, the patterning first transparent conductive layer 5a includes a plurality of first rectangular patterns 11 arranged at intervals in the front-back direction. Further, a wiring 12 for electrically connecting the first rectangular pattern 11 to an integrated circuit (not shown) is integrally connected to the right end of the first rectangular pattern 11 .

As shown in FIG. 3B , the patterned second transparent conductive layer 8a has a second rectangular shape elongated in the front-back direction (orthogonal direction orthogonal to the left-right direction) as an example of the second pattern at a substantially central portion when viewed from the bottom. The phase pattern 13 is provided. Specifically, the patterning second transparent conductive layer 8a has a plurality of second rectangular patterns 13 disposed at intervals in the left-right direction. In addition, wiring 12 for electrically connecting the second rectangular pattern 13 to an integrated circuit (not shown) is integrally connected to the front or rear end.

When the first rectangular pattern 11 of the patterned first transparent conductive layer 5a and the second rectangular pattern 13 of the patterned second transparent conductive layer 8a are projected in the thickness direction (vertical direction) , are arranged to be orthogonal to each other.

The left-right length (long side length) of the first rectangular pattern 11 of the patterned first transparent conductive layer 5a is the length in the front-back direction of the second rectangular pattern 13 of the patterned second transparent conductive layer 8a. (long side length) longer than As a result, since the surface resistance value of the patterned first transparent conductive layer 5a having a long current travel distance can be reduced, the current transfer speed of the patterned first transparent conductive layer 5a can be improved or noise can be reduced. can As a result, the size of the image display device 20 can be increased.

As the patterning method, for example, each transparent conductive layer is covered with a mask for forming an electrode pattern, and each transparent conductive layer is etched with an etchant. As the etchant, an acid is preferably used. Examples of the acid include inorganic acids such as hydrogen chloride, hydrogen bromide, sulfuric acid, nitric acid and phosphoric acid, organic acids such as acetic acid, mixtures thereof, and aqueous solutions thereof.

4. Action effect

This transparent conductive film (1) includes a first transparent conductive layer (5), a first optical adjustment layer (4), a transparent substrate (2), a second optical adjustment layer (7), and a second transparent conductive layer (8). Since the first transparent conductive layer 5 and the second transparent conductive layer 8 are patterned, the patterned first transparent conductive layer 5a and the patterned second transparent conductive layer 8a (eg For example, the visibility of the electrode pattern) can be suppressed.

In addition, since the surface resistance value of the first transparent conductive layer 5 is 10 Ω/□ or more and 70 Ω/□ or less, the transparent conductive film 1 has a small surface resistance value of the first transparent conductive layer (5 ) is provided on one side. Therefore, the transparent conductive film 1 can exhibit relatively better electromagnetic wave shielding properties than a transparent conductive film having transparent conductive layers having a high surface resistance value on both sides.

In addition, since the surface resistance value of the second transparent conductive layer 8 is larger than that of the first transparent conductive layer 5 and is 50 Ω/□ or more and 150 Ω/□ or less, the second transparent conductive layer (8) can be made thinner relatively than the 1st transparent conductive layer (5). Moreover, the refractive index of the 2nd optical adjustment layer 7 is lower than the refractive index of the 1st optical adjustment layer 4. The light transmittance of the transparent conductive film 1 can be improved by these surface resistance values and refractive index.

In addition, in the film 1a for a touch panel in which each transparent conductive layer of this transparent conductive film 1 is all patterned, the patterned first transparent conductive layer 5a has a first rectangular pattern 11 elongated in the left-right direction. ), and the patterning second transparent conductive layer 8a is provided with a second rectangular pattern 13 elongated in the front-back direction. Further, the length of the first rectangular pattern 11 in the left-right direction is longer than the length of the second pattern in the front-back direction. Therefore, since the surface resistance value of the patterned first transparent conductive layer 5a having a long current movement distance can be reduced, the current transfer speed of the patterned first transparent conductive layer 5a can be improved or noise can be reduced. can As a result, since it is possible to achieve an improvement in the current speed of the transparent conductive film 1 as a whole and a reduction in noise, the size of the image display device 20 can be increased.

<Image display device>

Next, an embodiment of the image display device 20 will be described. As shown in FIG. 4 , an embodiment of the image display device 20 includes a transparent protective plate 21, a first transparent adhesive layer 22, a touch panel film 1a, and a second transparent adhesive layer. (23) and an image display element (24) are provided in this order. In Fig. 4, the upper side is the element side, and the lower side is the visual side.

The transparent protective plate 21 is a layer for protecting internal members of the image display device 20, such as the image display element 24, against impact or contamination from the outside.

Examples of the transparent protective plate 21 include a resin plate made of hard resins such as acrylic resin and polycarbonate resin, for example, a glass plate.

The thickness of the transparent protective plate 21 is, for example, 10 μm or more, preferably 500 μm or more, and, for example, 10 mm or less, more preferably 5 mm or less.

The 1st transparent adhesive layer 22 is a layer for adhering the transparent protective plate 21 and the film 1a for touch panels. The first transparent pressure-sensitive adhesive layer 22 has a film shape and is disposed on the transparent protective plate 21 . More specifically, the first transparent pressure-sensitive adhesive layer 22 is between the transparent protective plate 21 and the touch panel film 1a, the upper surface of the transparent protective plate 21 and the lower surface of the touch panel film 1a (patterning It is arrange|positioned so that it may contact the 2nd transparent conductive layer (8a).

The first transparent adhesive layer 22 is formed of a transparent adhesive composition. The composition of the adhesive composition is not limited, but examples thereof include acrylic adhesives, rubber adhesives (butyl rubber, etc.), silicone adhesives, polyester adhesives, polyurethane adhesives, polyamide adhesives, epoxy adhesives, vinylalkyl ether adhesives, A fluororesin type adhesive etc. are mentioned.

The thickness of the first transparent pressure-sensitive adhesive layer 22 (the distance from the upper surface of the transparent protective plate 21 to the lower surface of the patterned second transparent conductive layer 8a) is, for example, 1 μm or more, preferably 5 μm or more, , and, for example, 300 μm or less, preferably 150 μm or less, and more preferably 50 μm or less.

The touch panel film 1a is disposed on the first transparent adhesive layer 22 so that the patterned first transparent conductive layer 5a is positioned on the upper side and the patterned second transparent conductive layer 8a is positioned on the lower side. . More specifically, in the film 1a for touch panels, between the first transparent adhesive layer 22 and the second transparent adhesive layer 23, the patterning second transparent conductive layer 8a is the first transparent adhesive layer ( 22), and the patterned first transparent conductive layer 5a is arranged so as to contact the second transparent pressure-sensitive adhesive layer 23.

Further, on the upper surface of the film 1a for a touch panel, the upper surface and side surface of the first rectangular pattern 11 of the patterned first transparent conductive layer 5a and exposure from the patterned first transparent conductive layer 5a The upper surface of the first optical adjusting layer 4 to be used is in contact with the first transparent pressure-sensitive adhesive layer 22 . On the lower surface of the touch panel film 1a, the lower surface and the side surface of the second rectangular pattern 13 of the patterned second transparent conductive layer 8a, and the second exposed from the patterned second transparent conductive layer 8a. The upper surface of the 2 optical adjustment layer 7 is in contact with the second transparent pressure-sensitive adhesive layer 23 .

The 2nd transparent adhesive layer 23 is a layer for adhering the image display element 24 and the film 1a for touch panels. The 2nd transparent adhesive layer 23 has a film shape, and is arrange|positioned on the film 1a for touch panels. More specifically, the second transparent pressure-sensitive adhesive layer 23 is between the touch panel film 1a and the image display element 24, the upper surface of the touch panel film 1a and the lower surface of the image display element 24 placed in contact with

The 2nd transparent adhesive layer 23 is formed from the same adhesive composition as the 1st transparent adhesive layer 22. The thickness of the second transparent adhesive layer 23 is the same as that of the first transparent adhesive layer 22 .

The image display element 24 is disposed on the second transparent pressure-sensitive adhesive layer 23 . More specifically, the image display element 24 has a second transparent pressure-sensitive adhesive layer 23 so that the image display surface 25 is lower and the image display surface 25 contacts the upper surface of the second transparent pressure-sensitive adhesive layer 23. ) is placed on the upper surface of

As the image display element 24, a liquid crystal cell, organic EL, etc. are mentioned, for example.

Since this image display apparatus 20 is equipped with the film 1a for touch panels, it has an electromagnetic wave shielding effect, and the patterning 1st transparent conductive layer 5a and the patterning 2nd transparent conductive layer 8a (electrode pattern ) while suppressing visibility, and having good light transmittance. Therefore, a large screen can be achieved.

In the image display device 20, the image display element 24 is disposed on the patterned first transparent conductive layer 5a side (upper side). Therefore, the distance between the patterned first transparent conductive layer 5a (first transparent conductive layer 5) having a strong electromagnetic wave shielding effect and the image display element 24 that generates electromagnetic waves is narrowed. Therefore, electromagnetic waves of the image display element 24 can be absorbed more reliably, and the electromagnetic wave shielding effect as the image display device 20 is excellent.

<Example of modification>

(1) In the embodiment shown in FIG. 1, the transparent conductive film 1 is sequentially from the bottom the second transparent conductive layer 8, the second optical adjustment layer 7, the second hard coat layer 6, the transparent The base material 2, the first hard coat layer 3, the first optical adjustment layer 4, and the first transparent conductive layer 5 are provided, but for example, although not shown, the second hard coat layer ( 6) and the first hard coat layer 3 may not be provided. That is, the transparent conductive film 1 is, in order from the bottom, the second transparent conductive layer 8, the second optical adjustment layer 7, the transparent substrate 2, the first optical adjustment layer 4, and the first transparent It consists of a conductive layer (5).

Preferably, the embodiment shown in FIG. 1 is mentioned from a viewpoint of abrasion property. It is the same as the above also about the film 1a for touch panels and the image display device 20.

(2) In the embodiment shown in Figs. 3A to 3B, the patterned first transparent conductive layer 5a has a first rectangular pattern 11 elongated in the left-right direction, and the patterned second transparent conductive layer 8a has Although not shown, for example, the patterning second transparent conductive layer 8a has a first rectangular pattern 11 that is long in the left-right direction. It is provided, and the patterning 1st transparent conductive layer 5a may also be provided with the 2nd rectangular pattern 13 long in the front-back direction.

In this embodiment, the length in the left-right direction of the first rectangular pattern 11 of the patterned second transparent conductive layer 8a is the length in the front-back direction of the second rectangular pattern 13 of the patterned first transparent conductive layer 5a. longer than the length

Preferably, the embodiment shown in Figs. 3A to 3B can be given from the viewpoint of being able to improve the current speed and noise of a transparent conductive layer having a long electrode pattern length.

(3) In the embodiment shown in FIGS. 3A to 3B , a first rectangular pattern 11 extending in the left-right direction as an example of the first pattern and a second rectangular pattern extending in the front-back direction as an example of the second pattern ( 13), but as shown in FIGS. 5A to 5B, for example, as an example of the first pattern, a plurality of rectangular patterns are continuous in the left-right direction as the first continuous rectangular pattern 14, and the second pattern As an example, it may be a second continuous rectangular pattern 15 in which a plurality of rectangular patterns are continued in the front-back direction.

That is, in the embodiment shown in FIGS. 5A and 5B , the first transparent conductive layer 5a to be patterned is provided with a plurality of first continuous rectangular patterns 14 arranged at intervals from each other in the left-right direction. In the first continuous quadrangular pattern 14, a plurality of substantially quadrangular patterns are arranged on a straight line so that their diagonal lines follow the left-right direction.

The patterning second transparent conductive layer 8a is provided with a plurality of second continuous rectangular patterns 15 arranged at intervals from each other in the front-back direction. In the second continuous quadrangular pattern 15, a plurality of substantially quadrangular patterns are arranged on a straight line so that their diagonal lines follow the front-back direction.

The first continuous rectangular pattern 14 of the patterned first transparent conductive layer 5a and the second continuous rectangular pattern 15 of the patterned second transparent conductive layer 8a are mutually related when projected in the thickness direction. They are arranged orthogonally. Further, when projected in the thickness direction, the first continuous quadrangular pattern constituting the first continuous quadrangular pattern 14 does not overlap with the quadrangular pattern constituting the second continuous quadrangular pattern 15. The pattern 14 and the second continuous rectangular pattern 15 are arranged. Further, when projected in the thickness direction, the pattern in which the first continuous rectangular pattern 14 and the second continuous rectangular pattern 15 are combined covers the entire surface of the substantially central portion of the touch panel film 1a. The first continuous rectangular pattern 14 and the second continuous rectangular pattern 15 are arranged.

(4) In the image display device 20 shown in FIG. 4, the film for touch panel 1a and the image display element 24 are positioned so that the image display element 24 is located on the side of the patterned first transparent conductive layer 5a. Although not shown, for example, the touch panel film 1a and the image display element 24 are disposed so that the image display element 24 is positioned on the side of the patterning second transparent conductive layer 8a. may be That is, in the image display device 20, the transparent protective plate 21 and the first transparent adhesive layer ( 22), the film 1a for touch panels, the 2nd transparent adhesive layer 23, and the image display element 24 may be provided in order from the lower side.

Preferably, the embodiment shown in FIG. 4 is mentioned from a viewpoint of the electromagnetic wave shielding effect of the image display apparatus 20 as a whole.

Example

Examples and comparative examples are shown below, and the present invention is explained more specifically. In addition, the present invention is not limited to Examples and Comparative Examples at all. In addition, the specific numerical values such as blending ratio (content ratio), physical property values, and parameters used in the description below are the blending ratio (content ratio), physical property values, and parameters corresponding to those described in the "Mode for Carrying Out the Invention" above. etc., can be replaced with the upper limit value (numerical value defined as "below" or "less than") or lower limit value (numerical value defined as "above" or "exceeding").

(Example 1)

On both sides of the transparent substrate (COP film, manufactured by Zeon, Japan, trade name “Zeonoa ZF-16”, thickness 100 μm), a hard coat composition (acrylic UV curable resin, manufactured by DIC, “Unidique RS29-120”) The diluted solution was applied using a gravure coater, and was heat-dried at 80°C for 1 minute. Thereafter, ultraviolet rays were irradiated using a high-pressure mercury lamp to form first and second hard coat layers (each thickness 1.0 μm, each refractive index 1.53). In this way, a laminate of the first hard coat layer, the transparent base material, and the second hard coat layer was obtained.

Subsequently, a dilution of the optical adjusting composition having a refractive index of 1.70 was applied to the surface of the first hard coat layer of the laminate using a gravure coater, and dried by heating at 60°C for 1 minute. Thereafter, ultraviolet rays were irradiated using a high-pressure mercury lamp to form a first optical adjusting layer (refractive index: 1.70, thickness: 80 nm). In addition, the refractive index was carried out similarly to the above except having used the optical adjustment composition used as 1.64, and formed the 2nd optical adjustment layer (refractive index 1.64, thickness 80 nm) on the surface of the 2nd hard-coat layer. In this way, a laminate of the first optical adjustment layer, the first hard coat layer, the transparent substrate, the second hard coat layer, and the first optical adjustment layer was obtained.

In addition, each optical adjusting composition was prepared by appropriately mixing a refractive index adjusting agent having a refractive index of 1.60 (manufactured by JSR, "Opstar") and a refractive index adjusting agent having a refractive index of 1.74 (manufactured by JSR, "Opstar KZ6734").

Next, the obtained laminate was put into a sputtering apparatus, and indium/tin oxide layers (ITO layers) were laminated on both sides of the laminate. As the gas, a mixed gas composed of 98% argon gas and 2% oxygen was used, and the pressure of the atmosphere was set to 0.4 Pa. In addition, as a sputtering target, a sintered body composed of 90% by mass of indium oxide and 10% by mass of tin oxide was used. In addition, the thickness of the first transparent conductive layer laminated on the first optical adjustment layer side was adjusted to 40 nm, and the thickness of the second transparent conductive layer laminated on the second optical adjustment layer side was adjusted to 30 nm.

Thus, a transparent conductive film composed of the first transparent conductive layer, the first optical adjustment layer, the first hard coat layer, the transparent substrate and the second hard coat layer, the first optical adjustment layer, and the second transparent conductive layer was obtained.

Next, by heating this transparent conductive film in an oven at 140°C for 90 minutes, the first and second transparent conductive layers were crystallized, and the double-sided transparent conductive film of Example 1 was manufactured.

(Examples 2 to 9 and Comparative Examples 1 to 5)

Except for changing the thickness and refractive index of the optical adjustment layer, and the thickness and surface resistance value of the transparent conductive layer to the thickness and refractive index of the optical adjustment layer described in Table 1, and the thickness and surface resistance value of the transparent conductive layer, A transparent conductive film was prepared in the same manner as in Example 1.

(Comparative Example 6)

A transparent conductive film was manufactured in the same manner as in Example 1, except that the first optical adjustment layer and the second optical adjustment layer were not formed.

About the transparent conductive film of each Example and each Comparative Example, the following measurement was performed, and the result is shown in Table 1.

<surface resistance>

The surface resistance (Ω/□) of each transparent conductive layer of the transparent conductive films of each Example and each Comparative Example was measured using the 4-terminal method.

<layer thickness>

The thickness of each hard coat layer and each optical adjustment layer was calculated based on the waveform from the interference spectrum using an instantaneous multi-photometry system (manufactured by Otsuka Electronics, "MCPD2000").

The thickness of each transparent conductive layer was measured by observing a cross-sectional view obtained by cutting the transparent conductive film with a transmission electron microscope (TEM).

<refractive index>

On a transparent film (COP film, manufactured by Zeon, Japan, “Zeonoa ZF-16”), only the hard coat layer to be measured was formed into a film, and a spectroscopic ellipsometer (manufactured by JA Wolam, model number FQTH-100) was formed. ) was used to measure the refractive index.

Moreover, only the optical adjustment layer which is a measuring object was formed into a film on the transparent film (same as the above), and the refractive index was measured using the spectroscopic ellipsometer (same as the above).

Moreover, when the adhesiveness of a transparent film and a hard-coat layer or an optical adjustment layer was poor, surface modification, such as a corona treatment, was performed suitably.

<Transmittance, color>

On both sides of the transparent conductive film of each Example and each Comparative Example, a transparent film ("Zeonor ZF-14", manufactured by Xeon, Japan, thickness 100 µm) were bonded together. This obtained a transmittance measurement sample (transparent film/adhesive/transparent conductive film/adhesive/transparent film). This sample was measured for visual sensitivity average transmittance and hues a* and b* at a wavelength of 380 to 700 nm using a spectrophotometer (manufactured by Murakami Color Co., Ltd., model number "Dot-3"). A result is shown in Table 1.

<Visibility of electrode pattern>

In the transparent conductive films of each Example and each Comparative Example, the first transparent conductive layer and the second transparent conductive layer were etched using an etchant and patterned into the electrode patterns shown in Figs. 3A to 3B. The patterned transparent conductive film was visually observed from an oblique upward direction. A case where the electrode pattern was clearly visible was evaluated as ×, and a case where the electrode pattern was hardly visually recognized was evaluated as ○. A result is shown in Table 1.

In addition, although the said invention was provided as the exemplified embodiment of this invention, this is only a mere illustration and should not be interpreted limitedly. Modifications of the present invention that are clear to those skilled in the art are included in the claims described later.

The transparent conductive film and image display device of the present invention can be applied to various industrial products. For example, the transparent conductive film of the present invention is preferably used in an image display device including a touch panel.

1: transparent conductive film
2: transparent substrate
4: first optical adjustment layer
5: first transparent conductive layer
7: second optical adjustment layer
8: second transparent conductive layer
11: first rectangular pattern
13: second rectangular pattern
20: image display device
24: image display element

Claims (6)

A first transparent conductive layer, a first optical control layer, a transparent base material, a second optical control layer and a second transparent conductive layer are sequentially provided,
The surface resistance value of the second transparent conductive layer is greater than the surface resistance value of the first transparent conductive layer,
The surface resistance value of the first transparent conductive layer is 10 Ω/□ or more and 70 Ω/□ or less,
The surface resistance value of the second transparent conductive layer is 50 Ω/□ or more and 150 Ω/□ or less,
The transparent conductive film, characterized in that the refractive index of the second optical adjustment layer is smaller than the refractive index of the first optical adjustment layer. According to claim 1,
The transparent conductive film, characterized in that the thickness of the second transparent conductive layer is smaller than the thickness of the first transparent conductive layer. According to claim 1,
The refractive index of the first optical adjustment layer is 1.65 or more and 1.75 or less,
The refractive index of the second optical adjustment layer is 1.60 or more and 1.70 or less, characterized in that, the transparent conductive film. According to claim 1,
The transparent conductive film, characterized in that both the thickness of the first optical adjustment layer and the second optical adjustment layer is 100 nm or less. According to claim 1,
Both the first transparent conductive layer and the second transparent conductive layer are patterned;
The first transparent conductive layer has a first pattern elongated in one direction,
The second transparent conductive layer has a second pattern that is long in an orthogonal direction orthogonal to the one direction,
A length of the first pattern in one direction is longer than a length of the second pattern in an orthogonal direction, characterized in that, the transparent conductive film. The transparent conductive film according to claim 1;
An image display device characterized by comprising an image display element disposed on the side of the first transparent conductive layer of the transparent conductive film.

Images