JP5192792B2 - Transparent conductive film and manufacturing method thereof - Google Patents

Description

  The present invention relates to a transparent conductive film capable of simultaneously achieving high environmental resistance and high light transmittance and a method for producing the same. Such transparent conductive films are mainly used for touch panels, PDPs (portable display panels), LCDs (liquid crystal displays), ELs (electroluminescence) displays, solar cells, surface acoustic wave elements, infrared cuts, etc. It can be preferably used in coatings, gas sensors, prism sheets utilizing nonlinear optics, transparent magnetic materials, optical recording elements, optical switches, optical waveguides, optical splitters, photoacoustic materials, high-temperature heating heaters, and the like.

  In transparent conductive films used for touch panels, displays, solar cells, etc., transparent conductive oxides (TCO) such as indium tin oxide (ITO), tin oxide, and zinc oxide are widely used as transparent conductive layers included in the conductive films. ing. Such a transparent conductive layer can be formed by physical vapor deposition (PVD) such as magnetron sputtering or molecular beam epitaxy (PVD) or chemical vapor deposition (CVD) such as thermal CVD or plasma CVD, It is known that it can also be formed by an electroless method.

  Among TCOs, ITO is an excellent material as a transparent conductive material, and is now widely used for transparent conductive layers. However, there is a possibility that indium as a raw material may be depleted, and there is an urgent need to search for a material that can replace ITO in terms of resources and cost. Furthermore, with the demand for higher performance of products that use transparent conductive films, a technique for increasing the transparency of transparent conductive films is also desired.

  A representative example of the transparent conductive material replacing ITO is zinc oxide (ZnO). Non-patent document 1 describes that ZnO is excellent in transparency as compared with ITO, but is inferior in stability to moisture and heat.

By the way, a transparent conductive film used for a touch panel, for example, often requires impact resistance from the nature of the application. In Patent Documents 1 to 3, it is stated that impact resistance is improved by forming a coating layer on a transparent conductive layer. However, the nitride coating layer, the oxide coating layer, and the like described in these patent documents may have excellent stability against moisture and heat, but a problem remains in conductivity. On the other hand, some carbon materials have excellent conductivity, but the carbon films described in Patent Documents 1 to 3 are not effective in improving the stability to moisture and heat.
JP 2001-283634 A Japanese Patent Laid-Open No. 2003-34860 JP 2003-109434 A Supervised by Yutaka Sawada, "Transparent conductive film", p. 17, 2005, issued by CMC Publishing Co. Supervised by Hidetoshi Saito, “DLC Membrane Handbook”, page 495 and below, 2006, published by NTS Corporation

  As described above, for example, as important elements of a transparent conductive film used for a touch panel, transparency, impact resistance, stability against moisture and heat, and conductivity are conceivable. However, a transparent conductive film superior to the currently mainstream ITO film has not been put into practical use.

  Accordingly, an object of the present invention is to provide a transparent conductive film capable of simultaneously achieving high environmental variability and high light transmittance and a method for producing the same.

The transparent conductive film according to the present invention includes one or more transparent conductive layers on a transparent substrate and a plurality of hydrogen-containing carbon layers thereon, at least one of the transparent conductive layers includes zinc oxide, and contains hydrogen. At least two of the carbon layers are different from each other in at least one of the structure and composition, and the light transmittance of the transparent substrate on which one or more transparent conductive layers are deposited is T _{0 and a} plurality of layers of hydrogen-containing carbon When the light transmittance of the transparent substrate deposited up to the layer is T ₁ , the relationship of T ₁ / T ₀ ≧ 1.02 holds for light having a wavelength of 550 nm.

  Note that at least one of the multiple hydrogen-containing carbon layers preferably has a refractive index within the range of 1.40 to 1.70 with respect to light having a wavelength of 550 nm. Further, a transparent conductive oxide layer having a thickness of 20 nm or less and containing zinc oxide can be further included on the plurality of hydrogen-containing carbon layers.

  Furthermore, in the method for producing the transparent conductive film of the present invention, the hydrogen-containing carbon layer is preferably formed by a high-frequency plasma CVD method using methane gas or a mixed gas of methane and hydrogen as a raw material gas.

  According to the present invention as described above, it is possible to provide a transparent conductive film that is excellent in “transparency” and “environmental variability”, which are particularly important characteristics for touch panels, EL displays, solar cells, and the like. .

  Conventionally, a carbon film typified by a diamond-like carbon film has been coated for the purpose of reducing surface friction. In recent years, carbon films are expected to be applied to low dielectric constant films used in solar cells, compound semiconductor high-speed electronic devices, and the like (Non-patent Document 2). Patent Documents 1 to 3 disclose a transparent conductive film including a carbon film as a coating layer.

  Normally, these carbon films are formed by sputtering a target carbon material using an argon gas, and the deposited carbon film is an amorphous carbon film not containing hydrogen. Although such a carbon film manufacturing method can form a hard film, such a hard carbon film cannot produce a stable protective effect against moisture and heat. The present inventors use a carbon layer containing hydrogen in the structure (hereinafter referred to as a “hydrogen-containing carbon layer”) as a coating layer, so that the transparent conductive layer containing zinc oxide is resistant to moisture and heat. It was found that the characteristics can be stably maintained. The present inventors further found that the light transmittance of the transparent conductive layer covered with the hydrogen-containing carbon layer can be easily increased by adjusting the deposition conditions of the hydrogen-containing carbon layer.

  FIG. 1 is a schematic cross-sectional view showing a transparent conductive film according to an embodiment of the present invention. In this figure, a transparent conductive layer 2 containing zinc oxide is provided on a transparent substrate 1 having a thickness of 0.05 to 1.5 mm. The surface of the transparent conductive layer 2 is covered with a first type hydrogen-containing carbon layer 3 and a second type hydrogen-containing carbon layer 4 which are sequentially deposited. The first type hydrogen-containing carbon layer 3 and the second type hydrogen-containing carbon layer 4 have different structures and / or compositions.

  In addition, the 1st type hydrogen containing carbon layer 3 and the 2nd type hydrogen containing carbon layer 4 may reverse the order of lamination | stacking, and those lamination | stacking may be repeated 3 layers or more sequentially. In addition, another type of carbon layer may be included in the lamination of the first type hydrogen-containing carbon layer 3 and the second type hydrogen-containing carbon layer 4. Furthermore, it is needless to say that the transparent conductive layer 2 does not need to be a single layer and may be replaced with a plurality of TCO layers as long as it includes at least one zinc oxide layer.

  The transparent substrate 1 only needs to be transparent at least in the visible light region, and may be either a hard material or a soft material. Typical examples of such a hard material include glass materials such as alkali glass, borosilicate glass, and non-alkali glass, but a sapphire substrate or the like can also be used. When a glass substrate is used, the thickness can be arbitrarily selected according to the purpose of use, but a thickness in the range of 0.5 mm to 4.5 mm is preferable in view of the balance between ease of handling and weight. . That is, a glass substrate that is too thin is not easily strong enough to be broken by an impact. Conversely, a glass substrate that is too thick is not preferable because of its increased weight, and is also not preferable from the viewpoint of affecting the thickness of the device to which the transparent conductive film is applied and making it difficult to apply to a portable device. . Furthermore, a thick glass substrate is not preferable in terms of transparency and cost.

  On the other hand, as a flexible substrate material, a film made of a thermoplastic resin such as acrylic, polyester or polycarbonate, or a thermosetting resin such as polyurethane is a typical example, but particularly excellent optical isotropy and water vapor barrier properties are excellent. A film containing polycycloolefin as a main component can be preferably used. The polycycloolefin film can be formed as a polymer of norbornene, a copolymer of norbornene and olefin, a polymer of unsaturated alicyclic hydrocarbon such as cyclopentadiene, and the like. From the viewpoint of water vapor barrier properties, it is preferable that the main chain and side chain of the film constituting molecule do not contain a functional group having a large polarity, such as a carbonyl group or a hydroxyl group. Although the thickness of these soft substrates can be arbitrarily selected according to the purpose of use, the substrate is easy to handle if the thickness is in the range of about 0.03 mm to 3.0 mm. That is, a film that is too thin is not preferable because handling is difficult and strength is insufficient. On the other hand, a film that is too thick is not preferable from the viewpoint of transparency and cost, and it is not preferable from the viewpoint of affecting the thickness of the device to which the transparent conductive film is applied and making it difficult to apply to a portable device.

  When using a film as the substrate 1, the substrate film may have a retardation value by being stretched. If the substrate film has a retardation value, it is possible to produce a low reflection panel by combining with a polarizing plate, and it can be expected that the visibility of an image is greatly improved.

  In order to give a retardation value to the substrate film, a known method can be used. For example, a stretching process such as uniaxial stretching or biaxial stretching or an orientation process can be used. In this case, the orientation of the polymer skeleton can be promoted by maintaining the film near the glass transition temperature. The preferred range of the retardation value varies depending on the intended function of the transparent conductive film, but it is preferably in the range of 50 to 300 nm for the purpose of the antireflection function, and is approximately within the range of light that humans recognize most strongly. More preferably, it is about 137 nm, which is 1/4 with respect to the wavelength of 550 nm.

  For the transparent conductive layer 2 in the present invention, zinc oxide is used even in TCO, from the viewpoint of high transparency and the difficulty of causing a reduction reaction against hydrogen plasma existing during deposition of the hydrogen-containing carbon layer. A doping agent can be added to the transparent conductive layer for the purpose of resistivity control and stability. Examples of the doping agent include compounds containing aluminum, gallium, indium, tin, boron, and the like, and compounds containing phosphorus, nitrogen, and the like.

  As a method for depositing the transparent conductive layer 2, various methods can be used as long as a uniform thin film can be formed. For example, vapor deposition methods such as PVD methods such as sputtering and vapor deposition, various CVD methods, and a solution containing a transparent conductive layer raw material are applied by spin coating, roll coating, spraying, dipping, etc., and then transparent by heat treatment A method of forming a conductive layer can be used. However, the vapor deposition method is preferable from the viewpoint of easily forming a thin film having a thickness of nanometer level.

  When the transparent conductive layer is formed by vapor deposition, the preferred substrate temperature depends on the softening temperature of the substrate, but is preferably from room temperature to the glass transition temperature of the substrate, and is about 30 ° C. above the glass transition temperature of the substrate. A lower temperature is more preferred. That is, if the substrate temperature is too low, the crystallinity of the transparent conductive layer is deteriorated, and the desired transparency and conductivity may not be achieved. Conversely, if the substrate temperature is too high, the retardation value of the film substrate may change or disappear.

  Plasma discharge can be used for vapor deposition of the transparent conductive layer. Although there is no restriction | limiting in particular in the applied electric power which produces a plasma, It is preferable to exist in the range of 10W-600W from the viewpoint of productivity and crystallinity of a transparent conductive layer. If the applied power is too small, the transparent electrode layer may not be deposited. On the contrary, when the applied power is too large, there is a concern that the substrate may be damaged by plasma or the film forming apparatus may be damaged. As a carrier gas used at the time of depositing the transparent conductive layer, a gas used in a general vapor deposition method can be used. For example, argon, hydrogen, oxygen, nitrogen, or the like can be used.

  The hydrogen-containing carbon layers 3 and 4 are deposited for the purpose of protecting the zinc oxide transparent conductive layer against air and moisture, as well as improving durability against physical impact and improving light transmittance in the transparent conductive layer. The These hydrogen-containing carbon layers are preferably hydrocarbons containing hydrogen in the structure, and amorphous hydrocarbons and tetrahedral amorphous hydrocarbons can be preferably used from the viewpoint of physical strength and transparency. In addition, at least one of the hydrogen-containing carbon layers 3 and 4 preferably has a refractive index in the range of 1.40 to 1.70 with respect to light having a wavelength of 550 nm. By covering with a hydrogen-containing carbon layer having such a refractive index, the light transmittance of the transparent conductive film can be improved.

  The normal carbon layer is generally formed by a well-known technique such as CVD, sputtering, ion plating, or vapor deposition, but the hydrogen-containing carbon layer in the present invention is formed by high-frequency plasma CVD. Can only be formed. There are various types of RF, VHF, microwave, etc. in the frequency band of the high-frequency power source used in this high-frequency plasma CVD method, but a desired hydrogen-containing carbon layer can be obtained using any type of high-frequency power source. In addition, a general gas containing carbon and hydrogen can be used as the source gas, and depending on the desired structure of the hydrogen-containing carbon layer, for example, it is possible to use only methane gas or dilute it with hydrogen. it can. The applied power for generating plasma is not particularly limited, but is preferably in the range of 5W to 600W. That is, when the applied power is too small, the deposition of the hydrogen-containing carbon layer is not achieved. Conversely, when the applied power is too large, the transparent conductive layer 2 may be etched by excessive plasma.

  When the transparent conductive film is mainly used for a touch panel, an electroluminescent electrode material, a solar cell, etc., as shown in the schematic cross-sectional view of FIG. 2 for the purpose of improving the electrical contact property. On the hydrogen-containing carbon layer 4, an additional transparent conductive layer 5 of zinc oxide can be deposited to a thickness of 20 nm or less. That is, the contact property here means the ease of the flow of electricity at the interface between the transparent conductive film and the counter electrode or charge transfer layer. By forming the thin additional transparent conductive layer 5 in this way, the contact property of the transparent conductive film can be improved.

  The additional transparent conductive layer 5 does not have to be doped with priority given to transparency, but it is possible to increase the contribution to improving contact properties by doping. As the doping agent, for example, a compound containing aluminum, gallium, indium, tin, boron, or a compound containing phosphorus, nitrogen, or the like can be used.

  The additional transparent conductive layer 5 is preferably as thin as possible and is formed to a thickness of 20 nm or less, more preferably 10 nm or less. The additional transparent conductive layer 5 is intended to improve contact properties, and the surface resistivity of the transparent conductive film needs to be controlled by the lower transparent conductive layer 2 and the hydrogen-containing carbon layers 3 and 4. That is, the thickness of the additional transparent conductive layer 5 is 20 nm or less that does not affect the surface resistivity of the transparent conductive film. Further, the instability of the zinc oxide layer with respect to moisture and heat can be avoided by reducing its thickness to 20 nm or less.

  The surface resistivity of the transparent conductive film was measured by a four-probe pressure measurement method defined in JISK7194. The surface resistivity value varies depending on, for example, characteristics required for a touch panel or the like, but is preferably in a range of 200 to 2000 Ω / □. That is, if the surface resistivity is too large, it means that the transparent conductive layer is too thin, and the surface resistivity of the transparent conductive film is not stable, especially if it is left in a high temperature and high humidity environment, the surface resistivity is easy. To rise. On the contrary, if the sheet resistivity is too small, it means that the transparent conductive layer is too thick, and the transparent conductive layer is easily cracked by the internal stress, which causes problems such as a decrease in transmittance of the transparent conductive layer and an increase in cost.

The light transmittance of the transparent conductive film with respect to light having a wavelength of 550 nm was measured using an integrating sphere light transmittance measuring device defined in JISK7105. In the light transmittance of the transparent conductive film according to the present invention, the transmittance after forming the transparent conductive layer 2 on the transparent substrate 1 is T _0, and the transmittance after coating with the hydrogen-containing carbon layers 3 and 4 is T _{When it is 1} , it is an important feature to satisfy the relationship of T ₁ / T ₀ ≧ 1.02. However, these transmittances T ₁ and T ₂ relate to light having a wavelength of 550 nm as described above. That is, in the present invention, it has been found that by controlling the composition and structure of the hydrogen-containing carbon layer, an effect equivalent to or higher than that of a general low reflection film is exhibited.

  In the following, various examples will be described together with some comparative examples, corresponding to the embodiments of the invention described above.

Example 1
In Example 1 of the present invention, corresponding to FIG. 1, a transparent conductive layer 2 made of zinc oxide on an alkali-free glass substrate 1 (trade name OA-10, film thickness 0.7 mm, manufactured by Nippon Electric Glass Co., Ltd.). Was deposited by sputtering. As specific deposition conditions, the substrate temperature is set to 200 ° C. in the film formation chamber, argon gas is introduced as a carrier gas at a flow rate of 20 sccm, DC power of 200 W is applied under a pressure of 8 Pa, and 5 minutes. By performing the deposition, a zinc oxide layer 2 having a thickness of 50 nm was formed.

  A first type hydrogen-containing carbon layer 3 was deposited on the zinc oxide layer 2 by a high-frequency plasma CVD method. As specific deposition conditions, the substrate temperature is set to 200 ° C. in the film formation chamber, methane gas and hydrogen gas are introduced at flow rates of 10 sccm and 200 sccm, respectively, 200 W RF power is applied under a pressure of 70 Pa, and 20 The first-type hydrogen-containing carbon layer 3 having a thickness of 5 nm was formed by performing deposition for a minute. The first-type hydrogen-containing carbon layer 3 thus obtained had a refractive index of 1.90 with respect to light having a wavelength of 550 nm. This refractive index was obtained by fitting the measurement of a spectroscopic ellipsometer VASE (manufactured by JAA Woollam).

  A second type hydrogen-containing carbon layer 4 having a different composition was deposited on the first type hydrogen-containing carbon layer 3 by a high-frequency plasma CVD method. As specific deposition conditions, the substrate temperature is set to 200 ° C. in the film forming chamber, methane gas is introduced at a flow rate of 50 sccm, 200 W RF power is applied under a pressure of 70 Pa, and deposition is performed for 20 minutes. As a result, a second-type hydrogen-containing carbon layer 4 having a thickness of 80 nm was formed. The second type hydrogen-containing carbon layer 4 had a refractive index of 1.55 with respect to light having a wavelength of 550 nm.

  The surface resistivity of the transparent conductive film of Example 1 produced in this way was 290Ω / □, and the light transmittance for light having a wavelength of 550 nm was 90%.

Further, in this transparent conductive film, T ₁ / T ₀ = 1.07. This means that the light transmittance is remarkably improved by covering the zinc oxide layer 2 with the first type hydrogen-containing carbon layer 3 and the second type hydrogen-containing carbon layer 4.

  Furthermore, when the transparent conductive film of Example 1 was allowed to stand for 1 week in an environment of 85 ° C. and 85% RH (relative humidity), the surface resistivity slightly increased to 300Ω / □, but the light rays related to light having a wavelength of 550 nm. The transmittance remained at 90%. As can be seen from the comparison with Comparative Example 1 described later, the surface of the transparent electrode film is obtained by covering the zinc oxide layer 2 with the first type hydrogen-containing carbon layer 3 and the second type hydrogen-containing carbon layer 4. It means that the weather resistance regarding the resistivity is remarkably improved.

(Example 2)
In Example 2 of the present invention, first, as in Example 1, a zinc oxide layer 2, a first type hydrogen-containing carbon layer 3, and a second type hydrogen-containing carbon layer are formed on an alkali-free glass substrate 1. 4 were sequentially deposited.

  Thereafter, a third hydrogen-containing carbon layer (not shown) was further deposited on the second-type hydrogen-containing carbon layer 4 by a high-frequency plasma CVD method. The third hydrogen-containing carbon layer is formed under the same deposition conditions as the first-type first-type hydrogen-containing carbon layer 3 and has the same thickness, structure, composition, and refractive index. It is.

The surface resistivity of the transparent conductive film of Example 2 produced in this way was 320Ω / □, and the light transmittance for light having a wavelength of 550 nm was 86%. In this transparent conductive film, T ₁ / T ₀ = 1.02.

  Furthermore, when the transparent conductive film of Example 2 was left for 1 week in an environment of 85 ° C. and 85% RH, the surface resistivity remained at 320Ω / □, and the light transmittance for light having a wavelength of 550 nm was 86%. It remained.

  Compared to Example 1, the transparent conductive film of Example 2 includes an additional hydrogen-containing carbon layer, so that the surface resistivity slightly increases and the light transmittance slightly decreases. It can be seen that the weather resistance regarding the resistivity is improved. That is, it will be apparent that the transparent electrode film according to the present invention may include three or more hydrogen-containing carbon coating layers if desired.

(Example 3)
The transparent conductive film according to Example 3 of the present invention was different from Example 1 only in that the stacking order of the first type hydrogen-containing carbon layer 3 and the second type hydrogen-containing carbon layer 4 was reversed. .

In the thus produced transparent conductive film of Example 3, the sheet resistivity was 290Ω / □, and the light transmittance for light having a wavelength of 550 nm was 88%. Further, in this transparent conductive film, T ₁ / T ₀ = 1.03.

  Furthermore, when the transparent conductive film of Example 3 was allowed to stand for 1 week in an environment of 85 ° C. and 85% RH, the surface resistivity slightly increased to 300Ω / □, and the light transmittance for light having a wavelength of 550 nm was 88%. It remained.

  That is, from the comparison between Example 3 and Example 1, the first-type hydrogen-containing carbon layer 3 and the second-type hydrogen-containing carbon layer 4 can exhibit almost the same effect regardless of their stacking order. It will be understood.

Example 4
The transparent conductive film according to Example 4 of the present invention corresponds to FIG. 2, and in comparison with Example 1, only that an additional zinc oxide layer 5 was deposited on the second-type hydrogen-containing carbon layer 4. It was different.

  The deposition conditions for this additional zinc oxide layer 5 differed only in that the deposition time was reduced to 1 minute and the deposition thickness was reduced to 10 nm, as compared to the zinc oxide transparent conductive layer 2.

  The surface resistivity of the transparent conductive film of Example 4 produced in this way was 290Ω / □, and the light transmittance with respect to light having a wavelength of 550 nm was 90%.

  Furthermore, when the transparent conductive film of Example 4 was left for 1 week in an environment of 85 ° C. and 85% RH, the surface resistivity slightly increased to 300Ω / □, and the light transmittance with respect to light having a wavelength of 550 nm was 90%. It remained.

  That is, from the comparison between Example 4 and Example 1, even if a very thin additional zinc oxide layer having a thickness of 10 nm or less is deposited on the hydrogen-containing carbon coating layer, the characteristics and weather resistance of the transparent electrode film are improved. It will be clear that it will not have any adverse effect on it.

(Comparative Example 1)
The transparent conductive film as Comparative Example 1 was different from Example 1 only in that the deposition of the second type hydrogen-containing carbon layer 4 was omitted.

The surface resistivity of the transparent conductive film of Comparative Example 1 produced in this manner was 310Ω / □, and the light transmittance for light having a wavelength of 550 nm was 85%. Further, in this transparent conductive film, T ₁ / T ₀ = 1.01.

  Furthermore, when the transparent conductive film of Comparative Example 1 was left for 1 week in an environment of 85 ° C. and 85% RH, the surface resistivity remained at 310Ω / □, and the light transmittance for light having a wavelength of 550 nm was also 85%. It remained.

  That is, compared with Example 1, in the transparent conductive film of Comparative Example 1, the deposition of the second-type hydrogen-containing carbon layer 4 was omitted, so that the surface resistivity increased and the light transmittance decreased. doing.

(Comparative Example 2)
The transparent conductive film as Comparative Example 2 was different from Example 1 only in that the deposition of both the first-type and second-type hydrogen-containing carbon layers 3 and 4 was omitted.

  The surface resistivity of the transparent conductive film of this comparative example produced in this manner was 280Ω / □, and the light transmittance for light having a wavelength of 550 nm was 85%.

  In addition, when the transparent conductive film of Comparative Example 2 was left for 1 week in an environment of 85 ° C. and 85% RH, the surface resistivity greatly increased to 700Ω / □, and the light transmittance for light having a wavelength of 550 nm was 85%. It remained.

  That is, compared with Example 1, in the transparent conductive film of Comparative Example 2, since both the first-type and second-type hydrogen-containing carbon coating layers are omitted, the weather resistance regarding the surface resistivity is practical. It is low enough not to be suitable for.

  As described above, according to the present invention, it is possible to provide a transparent conductive film capable of simultaneously achieving high environmental variability and high light transmittance and a method for producing the same.

It is typical sectional drawing which shows the laminated structure of the transparent conductive film by one Embodiment of this invention. It is typical sectional drawing which shows the laminated structure of the transparent conductive film by other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Transparent substrate, 2 Transparent conductive layer, 1st type hydrogen-containing carbon layer, 4nd type 2 hydrogen-containing carbon layer, 5 Additional transparent electrode layer.

Claims (4)

Including one or more transparent conductive layers on the transparent substrate, and a plurality of hydrogen-containing carbon layers thereon,
At least one of the transparent conductive layers contains zinc oxide,
At least two of the hydrogen-containing carbon layers are different from each other in at least one of the structure and composition thereof
When the light transmittance of the transparent substrate on which the one or more transparent conductive layers are deposited is T ₀ and the light transmittance of the transparent substrate deposited on the plurality of hydrogen-containing carbon layers is T _1. A transparent conductive film characterized in that a relationship of T ₁ / T ₀ ≧ 1.02 holds for light having a wavelength of 550 nm.   2. The transparent conductive material according to claim 1, wherein at least one of the plurality of hydrogen-containing carbon layers has a refractive index within a range of 1.40 to 1.70 with respect to light having a wavelength of 550 nm. film.   The transparent conductive film according to claim 1, further comprising a transparent conductive oxide layer having a thickness of 20 nm or less and containing zinc oxide on the plurality of hydrogen-containing carbon layers. A method for producing the transparent conductive film according to claim 1,
The method for producing a transparent conductive film, wherein the hydrogen-containing carbon layer is formed by a high-frequency plasma CVD method using methane gas or a mixed gas of methane and hydrogen as a source gas.

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