JP4661995B2 - Transparent conductive laminated film - Google Patents

Description

  The present invention relates to a transparent conductive laminated film in which a high refractive index layer, a low refractive index layer, and a transparent conductive thin film layer are laminated in this order on a substrate made of a transparent plastic film. In particular, when used as a patterned electrode film such as a capacitive touch panel, the surface resistance value is low, the touch panel can be enlarged, and the optical characteristics in the part having the transparent conductive thin film layer and the part removed. Since the difference is small, it relates to a transparent conductive laminated film that can improve visibility.

  A transparent conductive film obtained by laminating a transparent thin film with low resistance on a substrate made of a transparent plastic film is used for applications utilizing the conductivity, for example, a liquid crystal display or electroluminescence (EL may be abbreviated as EL). ) Widely used in electrical and electronic fields such as flat panel displays such as displays and transparent electrodes of resistive touch panels.

  In recent years, an increasing number of cases where a capacitive touch panel is mounted on a mobile device such as a mobile phone or a portable music terminal. Such a capacitive touch panel has a configuration in which a dielectric layer is laminated on a patterned conductor, and is touched with a finger or the like to be grounded via the capacitance of the human body. At this time, a change occurs in the resistance value between the patterning electrode and the ground point, and the position input is recognized. However, when a conventional transparent conductive film is used, the difference in optical characteristics between the portion having the transparent conductive thin film layer and the removed portion is large, so that the patterning is conspicuous and it is arranged on the front surface of the display body such as a liquid crystal display. There was a problem that the visibility deteriorated.

In order to improve the transmittance or color of the transparent conductive film, a method of using light interference by laminating layers having different refractive indexes used in antireflection processing or the like has been proposed. That is, a method of using optical interference by providing layers having different refractive indexes between a transparent conductive thin film layer and a base film has been proposed (Patent Documents 1 to 3).
However, although these transparent conductive films described in Patent Documents 1 to 3 can improve the visibility as a transparent conductive film, when the transparent conductive thin film layer is patterned, there is no portion with the transparent conductive thin film. It is not considered to reduce the difference in the optical characteristics between the portions, and the patterned portions become conspicuous.

In recent years, an increase in the size of a touch panel mounted on a mobile device such as a mobile phone is desired. In particular, since the transparent conductive film for capacitance is patterned and used as described above, when the touch panel is enlarged, the wiring resistance of each pattern electrode is increased, and the operation speed is lowered. For this reason, a transparent conductive film having a low surface resistance value and inconspicuous patterning is desired.
Japanese Patent Laid-Open No. 11-286066 Japanese Patent No. 3626624 JP 2006-346878 A

  That is, an object of the present invention is to provide a liquid crystal display or the like by reducing the difference in optical properties between a portion having a transparent conductive thin film layer and a removed portion in view of the above-mentioned conventional problems and having a low surface resistance value. An object of the present invention is to provide a transparent conductive laminated film that has good visibility when used in a patterning and in which patterning is not conspicuous.

This invention is made | formed in view of the above situations, Comprising: The transparent conductive lamination which was able to solve said subject consists of the following structures.
1. A laminated film obtained by laminating a high refractive index layer, a low refractive index layer, and a transparent conductive thin film layer in this order on a substrate made of a transparent plastic film, wherein the refractive index of the high refractive index layer is 1.70-2. 50, the thickness is in the range of 4 to 20 nm, the refractive index of the low refractive index layer is 1.30 to 1.60, the thickness is in the range of 20 to 50 nm, and the transparent conductive thin film layer has an average crystal grain From an indium-tin composite oxide thin film having a diameter of 10 to 1000 nm and a tin oxide content of 0.5 to 8% by mass, the ratio of the amorphous part to the crystalline part being 0.00 to 0.90 The transparent conductive thin film has a specific resistance of 1.0 to 4.6 × 10 ⁻⁴ Ω · cm and a film thickness of 10 to 28 nm.
2. A dielectric layer having a refractive index of 1.40 to 1.70 is laminated on the transparent conductive thin film layer side of the transparent conductive thin film obtained by patterning the transparent conductive thin film layer of the transparent conductive laminated film described in 1 above. A transparent conductive laminated film characterized by that.
3. 3. A transparent conductive film characterized in that a difference in optical characteristics between a portion having a transparent conductive thin film layer and a portion not having the transparent conductive thin film layer by patterning of the transparent conductive laminated film described in 2 satisfies the following formulas (1) and (2): Laminated film.
0 ≦ | T1-T0 | ≦ 1.0 (1)
0 ≦ | b1-b0 | ≦ 1.0 (2)
(T1: Total light transmittance of the film of the part having the transparent conductive thin film layer,
b1: Color b value of a film having a transparent conductive thin film layer,
T0: total light transmittance of a film of a portion not having the transparent conductive thin film layer,
b0: Color b value of the film having no transparent conductive thin film layer).

  The transparent conductive laminated film of the present invention has a configuration in which a high refractive index layer, a low refractive index layer, and a transparent conductive thin film layer are laminated in this order on a substrate made of a transparent plastic film. When patterning, the difference in optical properties between the part with and without the transparent conductive thin film layer is small, so the patterning of the transparent conductive thin film layer is inconspicuous even when placed on the front of a display such as a liquid crystal display. The decline in sex can be suppressed. Moreover, the surface resistance value is low, and it can respond to the enlargement of a touch panel.

It is explanatory drawing of the transparent conductive laminated film of this invention.

As shown in FIG. 1, the transparent conductive laminated film of the present invention has a high refractive index layer (13), a low refractive index layer (14) and a transparent conductive thin film on a substrate (11) made of a transparent plastic film. It has the structure which laminated | stacked the layer (15) in this order.
Furthermore, as a preferred embodiment, the dielectric layer (20) may be laminated on the transparent conductive thin film layer side of the transparent conductive laminated film obtained by patterning the transparent conductive thin film layer of the transparent conductive laminated film.
Hereinafter, each layer will be described in detail.

(Base material made of transparent plastic film)
The substrate made of a transparent plastic film used in the present invention is formed by forming an organic polymer into a film by melt extrusion or solution extrusion into a film, and if necessary, stretching in the longitudinal direction and / or the width direction, A film that has been fixed and heat-relaxed. Organic polymers include polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene terephthalate, nylon 6, nylon 4, nylon 66, nylon 12, polyimide, polyamideimide, polyethersulfane, polyetheretherketone , Polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyether imide, polyphenylene sulfide, polyphenylene oxide, polystyrene, syndiotactic polystyrene, norbornene-based polymer, and the like.

  Among these organic polymers, polyethylene terephthalate, polypropylene terephthalate, polyethylene-2,6-naphthalate, syndiotactic polystyrene, norbornene polymer, polycarbonate, polyarylate and the like are preferable. These organic polymers may be copolymerized with a small amount of other organic polymer monomers, or may be blended with other organic polymers.

  It is preferable that the thickness of the base material which consists of a transparent plastic film used by this invention is 10-300 micrometers, More preferably, it is 20-150 micrometers. If the thickness of the plastic film is less than 10 μm, the mechanical strength is insufficient, and handling in the pattern forming process of the transparent conductive thin film becomes difficult, which is not preferable. On the other hand, if the thickness exceeds 300 μm, the thickness of the touch panel becomes too thick, which is not suitable for mobile devices.

  The substrate made of a transparent plastic film used in the present invention is a range that does not impair the purpose of the present invention, such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, ozone treatment, etc. A surface activation treatment may be performed.

  In addition, the base material made of the transparent plastic film used in the present invention mainly includes a curable resin for the purpose of improving adhesion with a high refractive index layer, imparting chemical resistance, and preventing precipitation of low molecular weight substances such as oligomers. You may provide the hardened | cured material layer ((12) of FIG. 1) made into a structural component.

  The curable resin is not particularly limited as long as it is a resin that is cured by application of energy such as heating, ultraviolet irradiation, electron beam irradiation, etc., and silicone resin, acrylic resin, methacrylic resin, epoxy resin, melamine resin, polyester resin, urethane Resin etc. are mentioned. From the viewpoint of productivity, a curable resin containing an ultraviolet curable resin as a main component is preferable.

  Examples of such ultraviolet curable resins are synthesized from polyfunctional acrylate resins such as acrylic acid or methacrylic acid ester of polyhydric alcohol, diisocyanate, polyhydric alcohol and hydroxyalkyl ester of acrylic acid or methacrylic acid. Such polyfunctional urethane acrylate resins can be mentioned. If necessary, a monofunctional monomer such as vinyl pyrrolidone, methyl methacrylate, or styrene can be added to these polyfunctional resins for copolymerization.

  In order to improve the adhesion between the high refractive index layer and the cured product layer, it is effective to further treat the cured product layer. Specific methods include a discharge treatment method that irradiates glow discharge or corona discharge, a method of increasing carbonyl group, carboxyl group, hydroxyl group, a chemical treatment method of treating with acid or alkali, and an amino group. And a method of increasing polar groups such as a hydroxyl group and a carbonyl group.

  The ultraviolet curable resin is usually used by adding a photopolymerization initiator. As the photopolymerization initiator, known compounds that absorb ultraviolet rays and generate radicals can be used without any particular limitation. Examples of such photopolymerization initiators include various benzoins, phenyl ketones, and benzophenones. And the like. The addition amount of the photopolymerization initiator is preferably 1 to 5 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin.

  The concentration of the resin component in the coating solution can be appropriately selected in consideration of the viscosity according to the coating method. For example, the proportion of the total amount of the ultraviolet curable resin and the photopolymerization initiator in the coating solution is usually 20 to 80% by mass. Moreover, you may add other well-known additives, for example, leveling agents, such as a silicone type surfactant and a fluorine type surfactant, to this coating liquid as needed.

  In the present invention, the prepared coating solution is coated on a substrate made of a transparent plastic film. The coating method is not particularly limited, and conventionally known methods such as a bar coating method, a gravure coating method, and a reverse coating method can be used.

  Moreover, it is preferable that the thickness of a hardened | cured material layer is the range of 0.1-15 micrometers, More preferably, it is 0.5-10 micrometers, Most preferably, it is 1-8 micrometers. When the thickness of the cured product layer is less than 0.1 μm, it becomes difficult to form a sufficiently cross-linked structure, so that chemical resistance is likely to be lowered, and adhesion due to low molecular weight such as oligomer is also liable to occur. . On the other hand, when the thickness of the cured product layer exceeds 15 μm, the productivity tends to decrease.

(High refractive index layer)
The refractive index of the high refractive index layer that can be used in the present invention is in the range of 1.70 to 2.50, preferably 1.90 to 2.30, more preferably 1.90 to 2.10. If it is less than 1.70, the difference in refractive index from the low refractive index layer is too small, so that when the transparent conductive thin film layer is patterned, the optical characteristics of the portion having the transparent conductive thin film layer and the portion not having the transparent conductive thin film layer can be made closer. It becomes difficult. On the other hand, when the refractive index exceeds 2.50, it becomes difficult to make the patterning in the oblique direction inconspicuous, and there is no industrially suitable material. Specific materials for the high refractive index layer include TiO ₂ , Nb ₂ O ₅ , ZrO ₂ , Ta ₂ O ₅ , ZnO, In ₂ O ₃ , SnO _2, and complex oxides thereof and zinc sulfide ZnS. . Among these, ZnO, In ₂ O ₃ , SnO ₂ and composite oxides thereof are preferable from the viewpoint of productivity. Further, from the viewpoint of environmental stability, an indium tin oxide composite oxide containing 25 to 60% by mass of SnO ₂ is particularly preferable. In addition, any oxide or sulfide may be added to these oxides or sulfides for adjusting the refractive index.

  The film thickness of the high refractive index layer is 4 to 20 nm, preferably 7 to 15 nm, more preferably 8 to 13 nm. When the film thickness is less than 4 nm, the film becomes discontinuous and the stability of the film decreases. On the other hand, when the film thickness exceeds 20 nm, the reflection of light becomes strong. Therefore, when the transparent conductive thin film layer is patterned, it becomes difficult to bring the optical characteristics of the portion having the transparent conductive thin film layer close to the portion without the transparent conductive thin film layer, When it is arranged on the front surface of a display body such as a liquid crystal display, the patterning of the transparent conductive thin film layer becomes conspicuous, and the visibility is lowered. However, it is preferable to control the optical film thickness (refractive index × film thickness) to be constant rather than arbitrarily changing the refractive index and film thickness of the high refractive index layer.

As a method for forming a high refractive index layer in the present invention, a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, a spray method, and the like are known. Can be used as appropriate, but sputtering is preferred from the viewpoint of reducing variations in film thickness.
In general, the sputtering method includes a reactive sputtering method in which a reactive gas is introduced from a metal target to produce a metal oxide, and a method in which a metal oxide is formed from an oxide target. In the reactive sputtering method, there is a transition region in which the film formation rate changes rapidly depending on the flow rate of the reactive gas. For this reason, it is preferable to use an oxide target in order to suppress variations in film thickness.

(Low refractive index layer)
The refractive index of the low refractive index layer used in the present invention is 1.30 to 1.60, preferably 1.40 to 1.55, and more preferably 1.43 to 1.50. When the refractive index is less than 1.30, a porous film is formed, and the electrical characteristics of the transparent conductive thin film layer formed thereon are deteriorated. On the other hand, when the refractive index exceeds 1.60, the interference of light with the transparent conductive thin film layer becomes too weak. Therefore, when the transparent conductive thin film layer is patterned, a portion having the transparent conductive thin film layer and a portion having no transparent conductive thin film layer It becomes difficult to make the optical characteristics close to each other, and when the liquid crystal display is placed on the front surface of a display body such as a liquid crystal display, the patterning of the transparent conductive thin film layer becomes conspicuous, and the visibility is lowered.
Specific material of the low refractive index _layer, SiO 2, _Al 2 _{O 3} transparent metal oxides and composite metal oxides such as _SiO 2 _-Al 2 _{O 3,} such _{as, CuF 2, CeF 2, MnF} 2, MgF 2 And metal fluorides such as these and complex fluorides thereof. In addition, any oxide or sulfide may be added to these oxides or fluorides for adjusting the refractive index.

The film thickness of the low refractive index layer is 20 to 50 nm, preferably 25 to 45 nm, more preferably 30 to 40 nm. If it exceeds 50 nm, the wavelength dependence becomes too strong due to light interference with the transparent conductive thin film layer. Therefore, when the transparent conductive thin film layer is patterned, the optical characteristics of the portion with and without the transparent conductive thin film layer It becomes difficult to bring close. On the other hand, when the thickness is less than 20 nm, light interference with the transparent conductive thin film layer hardly occurs and the transmittance cannot be improved. Therefore, when the transparent conductive thin film layer is patterned, the transparent conductive thin film layer and the portion having the transparent conductive thin film layer are present. It becomes difficult to bring the optical characteristics of the portion not to be close to each other, and the patterning of the transparent conductive thin film layer becomes conspicuous when arranged on the front surface of a display body such as a liquid crystal display, and the visibility is lowered.
However, it is preferable to control the optical film thickness (refractive index × film thickness) to be constant rather than arbitrarily changing the refractive index and film thickness of the low refractive index layer.

  As a method for forming a low refractive index layer in the present invention, a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, a spray method, and the like are known, and the above method is used depending on the required film thickness. Can be used as appropriate, but sputtering is preferred from the viewpoint of reducing variations in film thickness. In general, when forming by sputtering, a reactive DC or AC sputtering method is used. Impedance control for controlling the reactive gas flow rate so as to keep the voltage value of the DC or AC power source constant in order to improve the deposition rate, or the reactive gas flow rate so as to keep the emission intensity in the plasma of a specific element constant. A plasma emission method for controlling the pressure is used.

(Transparent conductive thin film layer)
Specific materials for the transparent conductive thin film in the present invention include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Such as things. Of these, indium-tin composite oxides are preferable from the viewpoints of environmental stability and circuit processability.

  In the present invention, the transparent conductive thin film layer is laminated, and the surface resistance value of the transparent conductive laminated film is preferably 50 to 300 Ω / □, more preferably 100 to 250 Ω / □, and more preferably 100 to 220 Ω / □. Therefore, it can be used as a transparent conductive laminated film for a touch panel having a large screen size. The surface resistance value is preferably as low as possible. However, since it is less than 50Ω / □, the thickness of the transparent conductive thin film layer becomes thick, and the patterning of the transparent conductive thin film layer becomes conspicuous, which is not preferable. On the other hand, when it exceeds 300Ω / □, the position recognition accuracy of the touch panel is deteriorated, which is not preferable.

  The thickness of the transparent conductive thin film is preferably in the range of 10 to 28 nm, more preferably 12 to 25 nm. When the film thickness of the transparent conductive thin film is less than 10 nm, it is difficult to obtain a thin film with a flat surface, and it is difficult to obtain good conductivity. On the other hand, when the film thickness of the transparent conductive thin film is greater than 28 nm, when the transparent conductive thin film layer is patterned, it becomes difficult to bring the optical characteristics of the portion having the transparent conductive thin film layer close to the portion without the transparent conductive thin film layer. May stand out.

The specific resistance of the transparent conductive thin film layer is preferably 1.0 × 10 ⁻⁴ Ω · cm or more and 4.6 × 10 ⁻⁴ Ω · cm or less. More preferably not more than ^{2.0 × 10 -4 Ω · cm~4.0 ×} 10 -4 Ω · cm. When the specific resistance is less than 1.0 × 10 ⁻⁴ Ω · cm, coloring of the transparent conductive thin film layer increases, and transparency tends to decrease. On the other hand, if the specific resistance exceeds 4.6 × 10 ⁻⁴ Ω · cm, the wiring resistance when the transparent conductive thin film layer is patterned increases, which is not preferable.

  The transparent conductive thin film layer of the present invention is preferably a crystalline thin film layer having an average crystal grain size of 10 to 1000 nm and a ratio of the amorphous part to the crystalline part of 0.00 to 0.90. .

Here, the definition of the average crystal grain size of the transparent conductive film is as follows.
When a transparent conductive film layer is observed under a transmission electron microscope, a polygonal region is defined as a crystal grain, and the area of the crystal grain is obtained. The value obtained by doubling the square root of the value obtained by dividing the area of the crystal grain by the circumference ratio π is defined as the crystal grain size.
For the crystal grains observed in the transparent conductive film layer under a transmission electron microscope, all crystal grain sizes appearing in the 40000 times magnified photograph are calculated. The average value of all crystal grain sizes is defined as the average crystal grain size.
Further, a method for estimating the ratio of the amorphous part to the crystalline part is calculated from the area ratio of the crystalline part and the amorphous part when observed under a transmission electron microscope.

The average crystal grain size of the transparent conductive film of the present invention is 10 to 1000 nm. Especially preferably, it is 20-800 nm, More preferably, it is 30-500 nm. When the average crystal grain size is smaller than 10 nm, it is shown that crystal nucleation is difficult to occur when a transparent conductive thin film is formed. Such a transparent conductive thin film in which crystal nucleation hardly occurs means that many defects exist in the film, and the specific resistance does not become low.
On the other hand, when the crystal grain size exceeds 1000 nm, the bending resistance is deteriorated, so that cracks are likely to occur when the transparent conductive thin film layer is patterned.

  The ratio of the amorphous part to the crystalline part in the transparent conductive film of the present invention is 0.00-0.90, preferably 0.00-0.70, more preferably 0.00-0.50. It is. When the ratio is greater than 0.90, it indicates that crystal nucleation is unlikely to occur when forming a transparent conductive thin film, and such a transparent conductive thin film that does not easily generate crystal nucleation is contained in the film. Many defects mean existence, and the specific resistance is difficult to decrease, which is not preferable.

  As for the content rate of the tin oxide contained in a transparent conductive thin film layer, 0.5-8 mass% is preferable. More preferably, it is 2-6 mass%. When the tin oxide content is less than 0.5% by mass, it is difficult to improve the carrier concentration. On the other hand, when the content of tin oxide exceeds 8% by mass, the amount of dopant that does not substitute for the In site increases, and the mobility of carriers decreases due to impurity scattering, making it difficult to lower the specific resistance. The amount of tin in the transparent conductive thin film layer can be analyzed by ESCA.

  The layer structure of the transparent conductive thin film may be a single layer structure or a laminated structure of two or more layers. In the case of a transparent conductive thin film having a laminated structure of two or more layers, the metal oxides constituting each layer may be the same or different.

As a method for forming a transparent conductive thin film in the present invention, a vacuum vapor deposition method, a sputtering method, a CVD method, an ion plating method, a spray method, and the like are known. Can be used as appropriate.
For example, in the case of the sputtering method, a normal sputtering method using an oxide target, a reactive sputtering method using a metal target, or the like is used. At this time, oxygen, nitrogen, or the like may be introduced as a reactive gas, or means such as ozone addition, plasma irradiation, or ion assist may be used in combination. In addition, a bias such as direct current, alternating current, and high frequency may be applied to the substrate as long as the object of the present invention is not impaired.

In order to obtain a crystalline transparent conductive thin film layer having a low specific resistance according to the present invention, the following two methods are effective.
(1) Remove water and organic substances in the film forming atmosphere.
(2) Increase the energy of the vapor deposition particles.

First, the method (1) will be described.
When forming the transparent conductive thin film layer, in the film forming atmosphere in which moisture and organic impurities are removed as much as possible, the energy drop of the vapor deposition particles is small, and migration on the substrate (film) surface is likely to occur. As a result, a transparent conductive film containing crystals in the transparent conductive thin film tends to occur. Therefore, it is possible to obtain a crystalline transparent conductive thin film layer having a large average crystal grain size and a ratio of the amorphous part to the crystalline part of 0.00 to 0.90.

Specifically, the ratio of moisture pressure to an inert gas (such as argon) in the film formation atmosphere is preferably 8.0 × 10 ^{−4 to} 3.0 × 10 ⁻³ . As specific achievement means, measures such as (1) sufficiently removing moisture in the plastic film before film formation, (2) providing a moisture adsorption cryopump in the film formation space, etc. are effective. . Among these, (1) In order to sufficiently remove the moisture in the plastic film before film formation, it is effective to heat the plastic film while running the plastic film in a vacuum. The effective heating temperature is 25-80 ° C. Examples of the heating method include a heating roll and an infrared heater. If it is less than 25 ° C., the plastic film cannot be effectively heated, and if it exceeds 80 ° C., there is a possibility that the plastic film is scratched or deformed. (2) A suitable moisture adsorption cryopump installed in the film formation space is POLYCOLD manufactured by Hakuto Co., Ltd.
In order to make the ratio of the moisture pressure to an inert gas (such as argon) less than 8.0 × 10 ⁻⁴ , the moisture pressure against the inert gas in an apparatus in which a large amount of a transparent plastic film is put into the film forming chamber. In order to reduce the ratio, a long vacuum removal time is required or a vacuum pump with a very high capacity is required, which makes economic implementation difficult. On the other hand, if the ratio of the moisture pressure to the inert gas in the film formation atmosphere exceeds 3.0 × 10 ⁻³ , the specific resistance is low and a crystalline transparent conductive thin film layer can be obtained due to a decrease in the energy of the deposited particles. It becomes difficult.

  The substrate (film) temperature during film formation is preferably -20 to 80 ° C. When the temperature exceeds 80 ° C., a large amount of impurity gas such as water and organic gas is generated from the film, so that the energy of the deposited particles decreases, the specific resistance is low, and it becomes difficult to obtain a crystalline transparent conductive thin film. . On the other hand, when the temperature is lower than -20 ° C, the transparent plastic film becomes brittle. The substrate temperature can be adjusted with a temperature control roll or the like.

Next, the method (2) will be described.
When forming the transparent conductive thin film layer, examples of a method for improving the energy of the deposited particles include an activation assist method such as an ion assist method and an ion plating method, and a high power impulse magnetron sputtering method. By using these methods, the energy of the vapor deposition atoms can be improved, and migration on the substrate (film) surface can easily occur. As a result, a transparent conductive thin film containing a crystalline part in the transparent conductive thin film and having a small specific resistance can be obtained.
Among the above methods, the high power magnetron sputtering method can use a conventional sputtering apparatus by replacing the sputtering power source. For example, the film forming conditions in the high power magnetron sputtering method are as follows: oxygen is introduced, argon gas is introduced to form a film forming pressure of 0.1 to 1.0 Pa, a charging voltage of 400 to 1000 V, and a pulse frequency of 10 to 500 Hz. By conducting discharge at a pulse width of 10 to 200 μs, a transparent conductive thin film having a small specific resistance and containing a crystalline part in the transparent conductive thin film can be obtained without causing an arcing phenomenon.

  In order to further reduce the specific resistance, energy may be applied by means such as heating and ultraviolet irradiation after film formation. Of these energy applying means, heat treatment in an oxygen atmosphere is preferable.

  The heat treatment temperature is preferably in the range of 80 to 200 ° C. If the temperature is less than 80 ° C., the substitution of the dopant hardly occurs and the carrier concentration is difficult to improve, so that it is insufficient for further reducing the specific resistance. On the other hand, when the temperature exceeds 200 ° C., it becomes difficult to maintain the flatness of the film, and the crystal size in the transparent conductive thin film becomes too large, resulting in a fragile transparent conductive thin film.

  Further, the heat treatment time is preferably in the range of 0.2 to 120 minutes. Furthermore, the range of 0.5 to 60 minutes is preferable. If it is less than 0.2 minutes, even if heat treatment is performed at a high temperature of about 220 ° C., the effect of improving the film quality is not sufficient, which is not preferable. On the other hand, heat treatment times exceeding 120 minutes are industrially unsuitable.

  The atmosphere for the heat treatment is preferably performed in a space filled with oxygen after exhausting to a pressure of 0.2 Pa or less in advance. The pressure at this time is preferably not more than atmospheric pressure.

(Dielectric layer (protective layer) having a refractive index of 1.40 to 1.70)
In the present invention, a dielectric layer having a refractive index of 1.40 to 1.70 is a protective layer that is laminated to protect a transparent conductive thin film when a transparent conductive laminated film is used as a display member. This layer has both the purpose and the purpose of increasing the change in capacitance when touched with a finger or the like and improving the position input accuracy.
The dielectric layer having a refractive index of 1.40 to 1.70, for _example, transparent metal oxide such as SiO 2, _Al 2 _{O 3} and composite metal oxides such as _SiO 2 _-Al 2 _{O 3,} acrylic, silicone Organic materials made of polyester resins are used. The refractive index can be measured with an Abbe refractometer.
The conductive laminated film of the present invention is not easily noticeable even when such a dielectric layer is provided, and is excellent in visibility.

(Optical characteristics of transparent conductive laminated film)
In the present invention, after patterning the transparent conductive thin film layer of the transparent conductive laminated film, the dielectric layer having a refractive index of 1.40 to 1.70 is laminated on the transparent conductive thin film layer side. It is important that the difference in optical characteristics between the portion having the conductive thin film layer and the portion not having the conductive thin film layer is small, and it is preferable to satisfy the following expressions (1) and (2).
0 ≦ | T1-T0 | ≦ 1.0 (1)
0 ≦ | b1-b0 | ≦ 1.0 (2)
(T1: Total light transmittance of the film of the part having the transparent conductive thin film layer,
b1: Color b value of a film having a transparent conductive thin film layer,
T0: total light transmittance of a film of a portion not having the transparent conductive thin film layer,
b0: Color b value of the film of the portion not having the transparent conductive thin film layer)

T1 is preferably 90% or more, more preferably 90.5% or more, b1 is preferably -2 to 2, more preferably -1.0 to 1.5, and still more preferably. 0-1.5.
The thickness of each layer of the transparent conductive laminated film thus prepared can be known from the film cross-sectional shape by a transmission electron microscope (TEM), and the refractive index of each layer depends on the wavelength dependence of the transmission and reflectance of the film. Can be obtained by optical simulation using a film thickness value obtained by TEM.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples. In addition, the performance of the transparent conductive laminated film was measured by the following method.

(1) Total light transmittance Based on JIS-K7136, the total light transmittance was measured using Nippon Denshoku Industries Co., Ltd. product and NDH-1001DP.
T1 and T0 in (1) have a transparent conductive thin film layer measured in a state where a dielectric layer having a refractive index of 1.52 is laminated on the transparent conductive thin film layer side on a patterned transparent conductive laminated film. It is the value of a part and a part without a transparent conductive thin film layer.

(2) Surface resistance value Based on JIS-K7194, the surface resistance value was measured by the 4-terminal method. As a measuring instrument, Lotest AMCP-T400 manufactured by Mitsubishi Oil Chemical Co., Ltd. was used.

(3) Color b value Based on JIS-K7105, the color b value was measured with standard light C / 2 using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., ZE-2000).
In addition, b1 and b0 in the formula (2) are transparent conductive thin film layers measured in a state in which a dielectric layer having a refractive index of 1.52 is laminated on the transparent conductive thin film layer side on the patterned transparent conductive laminated film. It is the value of the part which has and the part which does not have a transparent conductive thin film layer.

(4) Visibility evaluation After printing an etching resist on the transparent conductive laminated film, a 1 × 3 cm pattern was formed by immersion in 1N hydrochloric acid and alkaline immersion. A biaxially oriented polyethylene terephthalate (hereinafter abbreviated as PET) film having an acrylic adhesive layer with a refractive index of 1.52 on the transparent conductive thin film side was bonded as a protective film. Using FMV-BIBLOLOOX T70M / T manufactured by Fujitsu Ltd., the screen was displayed in white, and a film on which a protective film was bonded was placed in front of it, and the appearance of patterning was evaluated from various angles.
○: Patterning is hardly visible.
Δ: Patterning is slightly visible.
X: Patterning is visible.

(5) Film thickness of high refractive index layer, low refractive index layer, transparent conductive thin film layer A film sample piece in which a high refractive index layer, a low refractive index layer, and a transparent conductive thin film layer are laminated has a size of 1 mm × 10 mm. It cut out and embedded in the epoxy resin for electron microscopes. This was fixed to a sample holder of an ultramicrotome, and a cross-sectional thin section parallel to the short side of the embedded sample piece was produced. Next, in a section where the thin film of this section is not significantly damaged, a transmission electron microscope (manufactured by JEOL, JEM-2010) is used to obtain a photograph at an acceleration voltage of 200 kV and a bright field at an observation magnification of 10,000 times. The film thickness was determined from the photograph taken.

(6) Refractive Index of High Refractive Index Layer, Low Refractive Index Layer, and Transparent Conductive Thin Film Layer A spectroscopic ellipsometer (FE- manufactured by Otsuka Electronics Co., Ltd., FE-) was prepared on each silicon wafer under the same film forming conditions. 5000) was used to evaluate the refractive index at 550 nm. The refractive index was calculated by fitting the spectral transmittance measurement data of the film provided with each layer using optical simulation software. At this time, the value evaluated by the film thickness evaluation method was used for the film thickness of each layer. Furthermore, it was confirmed that the refractive index of each layer calculated in this way was not significantly different from the refractive index of each layer on the silicon wafer.

(7) Specific Resistance of Transparent Conductive Thin Film Specific resistance was calculated using the surface resistance value and the film thickness of the transparent conductive thin film layer.

(8) Average crystal grain size A film sample piece laminated with a transparent conductive thin film layer was cut into a size of 1 mm × 10 mm, and attached to the upper surface of an appropriate resin block with the conductive thin film surface facing outward. After trimming this, an ultrathin section approximately parallel to the film surface was prepared by a general ultramicrotome technique.
This section was observed with a transmission electron microscope (JEOL, JEM-2010), a conductive thin film surface portion having no significant damage was selected, and a photograph was taken at an acceleration voltage of 200 kV and a direct magnification of 40000 times.
When a transparent conductive film layer is observed under a transmission electron microscope, a polygonal region is defined as a crystal grain, and the area of the crystal grain is obtained. The value obtained by doubling the square root of the value obtained by dividing the area of the crystal grain by the circumference ratio π is defined as the crystal grain size.
For the crystal grains of indium oxide observed on the transparent conductive film layer under a transmission electron microscope, all crystal grain sizes are calculated. The average value of all crystal grain sizes is defined as the average crystal grain size.

(9) Ratio of amorphous part to crystalline part It was calculated from the area ratio of the crystalline part and the amorphous part when observed under a transmission electron microscope.

[Example 1]
A mixed solvent of toluene / MEK (80/20: mass ratio) as a solvent was added to 100 parts by mass of a photopolymerization initiator-containing ultraviolet curable acrylic resin (manufactured by Dainichi Seika Kogyo Co., Ltd., Seika Beam EXF-01J). Was added so as to be 50% by mass, and stirred to dissolve uniformly to prepare a coating solution.

The prepared coating solution was applied to a biaxially oriented transparent PET film (Toyobo Co., Ltd., A4300, thickness 100 μm) having an easy-adhesion layer on both sides using a Meyer bar so that the thickness of the coating film was 5 μm. . After drying at 80 ° C. for 1 minute, the coating film was cured by irradiating with ultraviolet rays (light quantity: 300 mJ / cm ² ) using an ultraviolet ray irradiation device (UB042-5AM-W type, manufactured by Eye Graphics Co., Ltd.). . Subsequently, the coating on the opposite surface was similarly provided, and then heated at 180 ° C. for 1 minute to reduce volatile components.

  Moreover, in order to remove the water | moisture content in a film before film forming, in order to expose the biaxially oriented transparent PET film which laminated | stacked this hardened | cured material layer to a vacuum, the rewinding process was performed in the vacuum chamber. The pressure at this time was 0.002 Pa, and the exposure time was 20 minutes. The temperature of the center roll was 40 ° C., and the film was passed through it.

Next, a transparent conductive thin film made of indium-tin composite oxide was formed as a high refractive index layer on the cured product layer. At this time, the pressure before sputtering was 0.0001 Pa, and the target was indium oxide containing 36% by mass of tin oxide (manufactured by Sumitomo Metal Mining Co., Ltd., density: 6.9 g / cm ³ ). DC of ² W / cm ² Power was applied. Further, Ar gas was flowed at 130 sccm, and O ₂ gas was flowed at a flow rate three times the O ₂ flow rate at which the surface resistance value was minimized, and a film was formed by DC magnetron sputtering in an atmosphere of 0.4 Pa.

In addition, while constantly monitoring the oxygen partial pressure of the atmosphere with a sputtering process monitor (manufactured by INFICON, Transpector XPR3), an oxygen gas flow meter and a flowmeter are provided so that the degree of oxidation in the indium-tin composite oxide thin film becomes constant. I went back to DC power. As described above, a high refractive index layer made of an indium-tin composite oxide having a thickness of 10 nm and a refractive index of 1.93 was deposited. The surface resistance value of the high refractive index layer thus obtained was 1 × 10 ⁶ Ω / □ or more.

Further, in order to form a SiO ₂ thin film as a low refractive index layer on the high refractive layer, a DC magnetron sputtering method using silicon as a target is performed with a vacuum degree of 0.27 Pa, a gas of Ar gas of 500 sccm, and an O ₂ gas. At a flow rate of 80 sccm.
Further, while constantly observing the voltage value during the film formation, the oxygen gas flow meter was footed back so that the voltage value was constant. As described above, a low refractive index layer having a thickness of 35 nm and a refractive index of 1.46 was deposited.

Next, a transparent conductive thin film made of indium-tin composite oxide was formed on the low refractive index layer. At this time, the pressure before sputtering and 0.0001 Pa, indium oxide containing 3 wt% tin oxide as a target (Sumitomo Metal Mining Co., density 7.1 g / cm ³⁾ used to, the 2W / cm ² DC Power was applied. Further, Ar gas was flowed at 130 sccm and O ₂ gas was flowed at a flow velocity at which the surface resistance value was minimized, and a film was formed by DC magnetron sputtering in an atmosphere of 0.4 Pa. The center roll temperature was adjusted to 10 ° C so that the film temperature was about 10 ° C.

  In addition, transparent conductivity made of an indium-tin composite oxide having a thickness of 20 nm and a refractive index of 1.96 is observed while observing the moisture pressure with respect to argon in the film formation atmosphere with a sputtering process monitor (manufactured by Inficon, Transpector XPR3). A thin film was deposited to produce a transparent conductive laminated film.

[Example 2]
A transparent conductive film is formed in the same manner as in Example 1 except that indium oxide containing 1% by mass of tin oxide (made by Sumitomo Metal Mining Co., Ltd., density 7.1 g / cm ³ ) is used as a target for forming the transparent conductive thin film. The laminated film was produced.

Example 3
The transparent conductive film was formed in the same manner as in Example 1 except that it was changed to indium oxide containing 5% by mass of tin oxide (manufactured by Sumitomo Metal Mining Co., Ltd., density 7.1 g / cm ³ ) as a target for forming the transparent conductive thin film. The laminated film was produced.

Example 4
Indium oxide containing 7.5% by mass of tin oxide as a target for forming a transparent conductive thin film (Sumitomo Metal Mining Co., Ltd., density 7.1 g / cm ³ ), center for performing rewinding treatment in a vacuum chamber A transparent conductive laminated film was produced in the same manner as in Example 1 except that the temperature of the roll was changed to 70 ° C.

Example 5
A transparent conductive laminated film was formed in the same manner as in Example 1 except that the temperature of the center roll when performing the rewinding process in the vacuum chamber in Example 1 was set to 70 ° C.

Example 6
A transparent conductive laminated film was formed in the same manner as in Example 1 except that the temperature of the center roll when performing the rewinding process in the vacuum chamber in Example 1 was 30 ° C.

Example 7
In Example 1, when forming a transparent conductive thin film made of indium-tin composite oxide on a low refractive index layer, a power source for high power impulse magnetron sputtering (HMP2 / 3) is used instead of a normal pulse DC power source. , Manufactured by Huttinga). At this time, the pressure before sputtering was set to 0.0001 Pa, and the target was indium oxide containing 3% by mass of tin oxide (manufactured by Sumitomo Metal Mining Co., Ltd., density 7.1 g / cm ³ ), charging voltage 500 V, pulse frequency The measurement was performed at 500 Hz and a pulse width of 150 μs. Further, sputtering was performed by flowing Ar gas at 130 sccm and O ₂ gas at a flow velocity at which the surface resistance value was minimized, and setting the center roll temperature to 10 ° C. in an atmosphere of 0.4 Pa.

  In addition, transparent conductivity made of an indium-tin composite oxide having a thickness of 20 nm and a refractive index of 2.01 while observing the moisture pressure against argon in the film formation atmosphere with a sputtering process monitor (manufactured by Inficon, Transpector XPR3). A thin film was deposited. Others were carried out similarly to Example 1, and formed the transparent conductive laminated film.

Example 8
A transparent conductive laminated film was prepared in the same manner as in Example 1 except that a thin film made of zirconia-silicon composite oxide (ZrO ₂ —SiO ₂ ) was formed as a high refractive index layer on the cured product layer in Example 1. Formed.
At this time, the pressure before sputtering was set to 0.0001 Pa, the target was ZrSi _{2 (} manufactured by Mitsui Metals), DC power of ² W / cm ² was applied, and the degree of vacuum was 0.27 Pa, gas The film was formed by flowing Ar gas at a flow rate of 500 sccm and O ₂ gas at a flow rate of 80 sccm. Further, while constantly observing the voltage value during the film formation, the oxygen gas flow meter was footed back so that the voltage value was constant. As described above, a high refractive index layer having a thickness of 12 nm and a refractive index of 1.75 was deposited.

Example 9
A transparent conductive laminated film was formed in the same manner as in Example 1 except that a thin film made of titanium oxide (TiO ₂ ) was formed as a high refractive index layer on the cured product layer in Example 1.
At this time, the pressure before sputtering is set to 0.0001 Pa, the target is Ti (made by Mitsui Metals), DC power of ² W / cm ² is applied, and the degree of vacuum is 0.27 Pa and the gas is applied by the direct current magnetron sputtering method. Film formation was performed by flowing Ar gas at 500 sccm and O ₂ gas at a flow rate of 80 sccm. Further, while constantly observing the voltage value during the film formation, the oxygen gas flow meter was footed back so that the voltage value was constant. As described above, a high refractive index layer having a thickness of 8 nm and a refractive index of 2.29 was deposited.

Example 10
A transparent conductive laminated film was formed in the same manner as in Example 1 except that a thin film made of zinc sulfide (ZnS) was formed as a high refractive index layer on the cured product layer in Example 1.
At this time, the pressure before sputtering was set to 0.0001 Pa, and the target was zinc sulfide (manufactured by Mitsui Metals). A high frequency power of 13.56 MHz of ² W / cm ² was applied, and the degree of vacuum was set to 0. Film formation was performed by flowing Ar gas at a flow rate of 27 sc and Ar gas at a flow rate of 500 sccm and O ₂ gas at a flow rate of 80 sccm. Further, while constantly observing the voltage value during the film formation, the oxygen gas flow meter was footed back so that the voltage value was constant. As described above, a high refractive index layer having a thickness of 7.5 nm and a refractive index of 2.43 was deposited.

Example 11
A transparent conductive laminated film was formed in the same manner as in Example 1 except that a thin film made of magnesium fluoride (MgF ₂ ) was formed as a low refractive index layer on the cured product layer in Example 1.
At this time, the pressure before sputtering was set to 0.0001 Pa, and the target was magnesium fluoride (made by Mitsui Metals). A high frequency power of 13.56 MHz of ² W / cm ² was applied, and the degree of vacuum was reduced to 0 by magnetron sputtering. The film was formed by flowing Ar gas as a gas at a flow rate of 500 sccm. Further, while constantly observing the voltage value during the film formation, the oxygen gas flow meter was footed back so that the voltage value was constant. As described above, a low refractive index layer having a thickness of 40 nm and a refractive index of 1.36 was deposited.

Example 12
A transparent conductive laminate was formed in the same manner as in Example 1 except that a thin film made of aluminum-silicon composite oxide (Al ₂ O ₃ —SiO ₂ ) was formed as a low refractive index layer on the cured product layer in Example 1. A film was formed.
At this time, the pressure before sputtering was set to 0.0001 Pa, the target was Al—Si (50:50 wt%) (made by Mitsui Metals), DC power of ² W / cm ² was applied, and the degree of vacuum was increased by magnetron sputtering. Was formed by flowing Ar gas at 500 sccm and O ₂ gas at a flow rate of 80 sccm. Further, while constantly observing the voltage value during the film formation, the oxygen gas flow meter was footed back so that the voltage value was constant. As described above, a low refractive index layer having a thickness of 35 nm and a refractive index of 1.55 was deposited.

Example 13
The transparent conductive laminated film obtained in the same manner as in Example 1 was heat-treated at 120 ° C. for 60 minutes. The heat treatment was performed by reducing the pressure to 0.1 Pa in advance and then substituting with oxygen.

[Comparative Example 1]
A transparent conductive laminated film was produced in the same manner as in Example 1 except that the film thickness of the transparent conductive thin film layer was changed to 22 nm without providing the high refractive index layer and the low refractive index layer.

[Comparative Example 2]
A transparent conductive laminated film was produced in the same manner as in Example 1 except that the high refractive index layer was not provided.

[Comparative Example 3]
A transparent conductive laminated film was produced in the same manner as in Example 1 except that the thickness of the low refractive index layer was 10 nm.

[Comparative Example 4]
A transparent conductive laminated film was produced in the same manner as in Example 1 except that the thickness of the low refractive index layer was 100 nm.

[Comparative Example 5]
The transparent conductive film is formed in the same manner as in Example 1 except that the target is the indium oxide containing 10% by mass of tin oxide (produced by Sumitomo Metal Mining Co., Ltd., density 7.1 g / cm ³ ) as the target for forming the transparent conductive thin film. The laminated film was produced.

[Comparative Example 6]
A transparent conductive laminated film was prepared in the same manner as in Example 1 except that it was changed to indium oxide containing no tin oxide (made by Sumitomo Metal Mining Co., Ltd., density 7.1 g / cm ³ ) as a target for forming the transparent conductive thin film. Produced.

[Comparative Example 7]
A transparent conductive laminated film was formed in the same manner as in Example 1 except that the temperature of the center roll when performing the rewinding treatment in the vacuum chamber in Example 1 was 20 ° C.

[Comparative Example 8]
A transparent conductive laminate was formed in the same manner as in Example 1 except that a thin film made of aluminum-silicon composite oxide (Al ₂ O ₃ —SiO ₂ ) was formed as a high refractive index layer on the cured product layer in Example 1. A film was formed.
At this time, the pressure before sputtering was set to 0.0001 Pa, the target was Al—Si (50:50 wt%) (made by Mitsui Metals), DC power of ² W / cm ² was applied, and the degree of vacuum was increased by magnetron sputtering. Was formed by flowing Ar gas at 500 sccm and O ₂ gas at a flow rate of 80 sccm. Further, while constantly observing the voltage value during the film formation, the oxygen gas flow meter was footed back so that the voltage value was constant. As described above, a high refractive index layer having a thickness of 22 nm and a refractive index of 1.55 was deposited.

[Comparative Example 9]
A transparent conductive laminated film was prepared in the same manner as in Example 1 except that a thin film made of zirconia-silicon composite oxide (ZrO ₂ —SiO ₂ ) was formed as a low refractive index layer on the cured product layer in Example 1. Formed.
At this time, the pressure before sputtering was set to 0.0001 Pa, the target was ZrSi ₂ (made by Mitsui Metals), DC power of ² W / cm ² was applied, and the degree of vacuum was 0.27 Pa, gas by the DC magnetron sputtering method. The film was formed by flowing Ar gas at a flow rate of 500 sccm and O ₂ gas at a flow rate of 80 sccm. Further, while constantly observing the voltage value during the film formation, the oxygen gas flow meter was footed back so that the voltage value was constant. As described above, a low refractive index layer having a thickness of 29 nm and a refractive index of 1.75 was deposited.

[Comparative Example 10]
The film thickness of the high refractive index layer was 13 nm, the film thickness of the low refractive index layer was 20 nm, the film thickness of the transparent conductive thin film layer was 60 nm, and 10% by mass of tin oxide was contained as a target when forming the transparent conductive thin film. Transparent conductive laminate in the same manner as in Example 1 except that indium oxide (Sumitomo Metal Mining Co., Ltd., density 7.1 g / cm ³ ) and the temperature of the center roll at the time of rewinding treatment in a vacuum chamber were set to 20 ° C. A film was prepared.

From the results of Table 1, the transparent conductive laminated films described in Examples 1 to 13 that satisfy the scope of the present invention are liquid crystal because the patterned portion does not stand out even if the transparent conductive thin film layer is patterned. When arranged and used in front of a display body such as a display, it was excellent in visibility. Further, since the surface resistance value is low, the screen size can be increased.
On the other hand, the transparent conductive laminated film according to Comparative Examples 1 to 4 and 8 to 10 in which the high refractive index layer, the low refractive index layer, and the transparent conductive thin film layer are not properly arranged, or the film thickness is not appropriate, Visibility was inferior because a portion that was not patterned and a portion that was not patterned were visible. The content of SnO _2, the transparent conductive laminated film of Comparative Examples 5 to 7, wherein the water pressure is not appropriate, high surface resistance value after heat treatment, can not be used for large screen size.

  The transparent conductive laminated film of the present invention has a low surface resistance and a small difference in optical characteristics between the patterned portion and the non-patterned portion of the transparent conductive thin film layer. , Excellent visibility. For this reason, it is particularly suitable as an electrode film for a capacitive touch panel.

10: Transparent conductive laminated film 11: Transparent plastic film (base material)
12: Cured material layer 13: High refractive index layer 14: Low refractive index layer 15: Transparent conductive thin film layer 20: Dielectric layer

Claims (3)

A laminated film obtained by laminating a high refractive index layer, a low refractive index layer, and a transparent conductive thin film layer in this order on a substrate made of a transparent plastic film, wherein the refractive index of the high refractive index layer is 1.70-2. 50, the thickness is in the range of 4 to 20 nm, the refractive index of the low refractive index layer is 1.30 to 1.60, the thickness is in the range of 20 to 50 nm, and the transparent conductive thin film layer has an average crystal grain From an indium-tin composite oxide thin film having a diameter of 10 to 1000 nm and a tin oxide content of 0.5 to 8% by mass, the ratio of the amorphous part to the crystalline part being 0.00 to 0.90 The transparent conductive thin film has a specific resistance of 1.0 to 4.6 × 10 ⁻⁴ Ω · cm and a film thickness of 10 to 28 nm. A dielectric layer having a refractive index of 1.40 to 1.70 is laminated on the transparent conductive thin film layer side of the transparent conductive thin film obtained by patterning the transparent conductive thin film layer of the transparent conductive laminated film according to claim 1. A transparent conductive laminated film characterized by being made. The transparent characteristic difference of the optical characteristic of the part which has the transparent conductive thin film layer by patterning of the transparent conductive laminated film of Claim 2 , and the part which does not have satisfy | fills the following (1) Formula and (2) Formula, Conductive laminated film.
0 ≦ | T1-T0 | ≦ 1.0 (1)
0 ≦ | b1-b0 | ≦ 1.0 (2)
(T1: Total light transmittance of the film of the part having the transparent conductive thin film layer,
b1: Color b value of a film having a transparent conductive thin film layer,
T0: total light transmittance of a film of a portion not having the transparent conductive thin film layer,
b0: Color b value of the film of the portion not having the transparent conductive thin film layer)