Transparent Conductive Film

Abstract

This transparent conductive film (X) comprises a transparent base material (10) and a light-transmissive conductive layer (20), in said order in the thickness direction (D). The light-transmissive conductive layer (20) contains krypton. The compressive residual stress in the light-transmissive conductive layer (20) is less than 490 MPa.

Description

[Technical Field]

[0001] The present invention relates to a transparent conductive film. [Background technology]

[0002] Conventionally, transparent conductive films have been known that include a transparent substrate film and a transparent conductive layer (light-transmitting conductive layer) in that order in the thickness direction. The light-transmitting conductive layer is used as a conductive film for patterning transparent electrodes in various devices such as liquid crystal displays, touch panels, and optical sensors. The light-transmitting conductive layer is also sometimes used as an antistatic layer provided in devices. The light-transmitting conductive layer is formed, for example, by forming a film of conductive oxide on the substrate film using a sputtering method. In this sputtering method, an inert gas such as argon is conventionally used as a sputtering gas for colliding with a target (film-forming material supply material) and ejecting atoms from the target surface. Technology related to such transparent conductive films is described, for example, in Patent Document 1 listed below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-334924 Summary of the Invention [Problem to be solved by the invention]

[0004] The light-transmitting conductive layer of a transparent conductive film is required to have low resistance. This requirement is particularly strong for transparent conductive films used as transparent electrodes. Transparent conductive films are also required to be resistant to warping.

[0005] The present invention provides a transparent conductive film that is suitable for reducing the resistance of a light-transmitting conductive layer and suppressing warping of the film. [Means for solving the problem]

[0006] The present invention [1] includes a transparent conductive film comprising a transparent substrate and a light-transmitting conductive layer in this order in the thickness direction, the light-transmitting conductive layer containing krypton, and the light-transmitting conductive layer having a compressive residual stress of less than 490 MPa in an in-plane direction perpendicular to the thickness direction.

[0007] The present invention [2] includes the transparent conductive film according to the above [1], wherein the average number of grain boundaries in the in-plane direction of the light-transmitting conductive layer is less than 12 / μm.

[0008] The present invention [3] includes the transparent conductive film according to the above [1] or [2], wherein the light-transmitting conductive layer contains an indium-containing conductive oxide.

[0009] The present invention [4] includes the transparent conductive film according to any one of the above [1] to [3], wherein the light-transmitting conductive layer does not contain xenon.

[0010] The present invention [5] is characterized in that the light-transmitting conductive layer has a thickness of 2.2 × 10 -4 The transparent conductive film according to any one of [1] to [4] above has a specific resistance of Ω·cm or less.

[0011] The present invention [6] includes the transparent conductive film according to any one of the above [1] to [5], wherein the light-transmitting conductive layer has a thickness of 30 nm or more. [Effects of the Invention]

[0012] The transparent conductive film of the present invention is suitable for reducing the resistance of the light-transmitting conductive layer and suppressing warping of the film, since the light-transmitting conductive layer on the transparent substrate contains krypton and has a compressive residual stress of less than 490 MPa in the in-plane direction. [Brief explanation of the drawings]

[0013] [Figure 1]1 is a cross-sectional view of an embodiment of a transparent conductive film of the present invention. [Figure 2] 2A and 2B are cross-sectional schematic diagrams of modified examples of the transparent conductive film of the present invention, in which the light-transmitting conductive layer includes a first region and a second region in this order from the transparent substrate side. The light-transmitting conductive layer includes a second region and a first region in this order from the transparent substrate side. [Figure 3] This shows a method for manufacturing the transparent conductive film shown in Fig. 1. Fig. 3A shows a step of preparing a transparent resin film, Fig. 3B shows a step of forming a functional layer on the transparent resin film, Fig. 3C shows a step of forming a light-transmitting conductive layer on the functional layer, and Fig. 3D shows a step of crystallizing the light-transmitting conductive layer. [Figure 4] This shows the transparent conductive film shown in FIG. 1 in which the light-transmitting conductive layer is patterned. [Figure 5] 1 is a graph showing the relationship between the amount of oxygen introduced when forming a light-transmitting conductive layer by sputtering and the resistivity of the formed light-transmitting conductive layer. DETAILED DESCRIPTION OF THE INVENTION

[0014] 1 is a cross-sectional schematic diagram of a transparent conductive film X, which is one embodiment of the transparent conductive film of the present invention. The transparent conductive film X includes a transparent substrate 10 and a light-transmitting conductive layer 20, in this order, toward one side in a thickness direction D. The transparent conductive film X, the transparent substrate 10, and the light-transmitting conductive layer 20 each have a shape that extends in a direction (plane direction) perpendicular to the thickness direction D. The transparent conductive film X is an element included in touch sensor devices, light control elements, photoelectric conversion elements, heat ray control members, antenna members, electromagnetic wave shielding members, heater members, lighting devices, image display devices, and the like.

[0015] In this embodiment, the transparent substrate 10 includes a transparent resin film 11 and a functional layer 12 in this order toward one side in the thickness direction D.

[0016] The transparent resin film 11 is a flexible, transparent resin film. Examples of materials for the transparent resin film 11 include polyester resin, polyolefin resin, acrylic resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, and polystyrene resin. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include polyethylene, polypropylene, and cycloolefin polymer. Examples of acrylic resins include polymethacrylate. The material for the transparent resin film 11 is preferably selected from the group consisting of polyolefin resin, acrylic resin, polycarbonate resin, melamine resin, and polyester resin, and more preferably PET, because it is easy to obtain a transparent resin film 11 with high surface smoothness. High surface smoothness of the transparent resin film 11 contributes to reducing the resistance of the light-transmitting conductive layer 20 and also contributes to obtaining a transparent conductive film X with reduced warpage.

[0017] The surface of the transparent resin film 11 facing the functional layer 12 may be subjected to a surface modification treatment, such as a corona treatment, a plasma treatment, an ozone treatment, a primer treatment, a glow treatment, or a coupling agent treatment.

[0018] The thickness of the transparent resin film 11 is preferably 1 μm or more, more preferably 10 μm or more, and even more preferably 30 μm or more. The thickness of the transparent resin film 11 is preferably 300 μm or less, more preferably 200 μm or less, even more preferably 100 μm or less, and particularly preferably 75 μm or less. These configurations regarding the thickness of the transparent resin film 11 are suitable for ensuring the handleability of the transparent conductive film X.

[0019] The total light transmittance (JIS K 7375-2008) of the transparent resin film 11 is preferably 60% or more, more preferably 80% or more, and even more preferably 85% or more. Such a configuration is suitable for ensuring the transparency required of the transparent conductive film X when the transparent conductive film X is used in touch sensor devices, light control elements, photoelectric conversion elements, heat ray control members, antenna members, electromagnetic wave shielding members, heater members, lighting devices, image display devices, etc. The total light transmittance of the transparent resin film 11 is, for example, 100% or less.

[0020] In this embodiment, the functional layer 12 is located on one surface of the transparent resin film 11 in the thickness direction D. In addition, in this embodiment, the functional layer 12 is a hard coat layer that makes it difficult for scratches to form on the exposed surface (top surface in FIG. 1 ) of the light-transmitting conductive layer 20.

[0021] The hard coat layer is a cured product of a curable resin composition. Examples of resins contained in the curable resin composition include polyester resin, acrylic resin, urethane resin, amide resin, silicone resin, epoxy resin, and melamine resin. Examples of the curable resin composition include an ultraviolet-curable resin composition and a thermosetting resin composition. From the viewpoint of being useful for improving the production efficiency of the transparent conductive film X because it can be cured without high-temperature heating, an ultraviolet-curable resin composition is preferably used as the curable resin composition. Specific examples of the ultraviolet-curable resin composition include the hard coat layer-forming composition described in JP 2016-179686 A.

[0022] The surface of the functional layer 12 facing the light-transmitting conductive layer 20 may be subjected to a surface modification treatment. Examples of surface modification treatments include corona treatment, plasma treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment.

[0023] The thickness of the functional layer 12 as a hard coat layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. Such a configuration is suitable for imparting sufficient scratch resistance to the light-transmitting conductive layer 20. From the viewpoint of ensuring the transparency of the functional layer 12, the thickness of the functional layer 12 as a hard coat layer is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less.

[0024] The thickness of the transparent substrate 10 is preferably 1 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and particularly preferably 30 μm or more. The thickness of the transparent substrate 10 is preferably 310 μm or less, more preferably 210 μm or less, even more preferably 110 μm or less, and particularly preferably 80 μm or less. These configurations regarding the thickness of the transparent substrate 10 are suitable for ensuring the handleability of the transparent conductive film X.

[0025] The total light transmittance (JIS K 7375-2008) of the transparent substrate 10 is preferably 60% or more, more preferably 80% or more, and even more preferably 85% or more. Such a configuration is suitable for ensuring the transparency required of the transparent conductive film X when the transparent conductive film X is provided in a touch sensor device, a light control element, a photoelectric conversion element, a heat ray control member, an antenna member, an electromagnetic wave shielding member, a heater member, a lighting device, an image display device, etc. The total light transmittance of the transparent substrate 10 is, for example, 100% or less.

[0026] In this embodiment, the light-transmitting conductive layer 20 is located on one surface of the transparent substrate 10 in the thickness direction D. The light-transmitting conductive layer 20 is a crystalline film that has both light transparency and conductivity.

[0027] The light-transmitting conductive layer 20 is a layer formed from a light-transmitting conductive material, which contains, for example, a conductive oxide as a main component.

[0028] Examples of conductive oxides include metal oxides containing at least one metal or metalloid selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. Specifically, examples of conductive oxides include indium-containing conductive oxides and antimony-containing conductive oxides. Examples of indium-containing conductive oxides include indium-tin composite oxide (ITO), indium-zinc composite oxide (IZO), indium-gallium composite oxide (IGO), and indium-gallium-zinc composite oxide (IGZO). Examples of antimony-containing conductive oxides include antimony-tin composite oxide (ATO). From the viewpoint of achieving high transparency and good electrical conductivity, indium-containing conductive oxides are preferred, and ITO is more preferred. This ITO may contain a metal or metalloid other than In and Sn in an amount less than the respective contents of In and Sn.

[0029] When ITO is used as the conductive oxide, the ratio of the tin oxide content to the total content of indium oxide (In2O3) and tin oxide (SnO2) in the ITO is preferably 0.1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and particularly preferably 7% by mass or more. The ratio of the number of tin atoms to the number of indium atoms in the ITO used (number of tin atoms / number of indium atoms) is preferably 0.001 or more, more preferably 0.03 or more, even more preferably 0.05 or more, and particularly preferably 0.07 or more. This configuration is suitable for ensuring the durability of the light-transmitting conductive layer 20. Furthermore, the ratio of the tin oxide content to the total content of indium oxide (In2O3) and tin oxide (SnO2) in the ITO used is preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 12% by mass or less. The ratio of the number of tin atoms to the number of indium atoms in the ITO used (number of tin atoms / number of indium atoms) is preferably 0.16 or less, more preferably 0.14 or less, and even more preferably 0.13 or less. These configurations are suitable for obtaining a light-transmitting conductive layer 20 that is easily crystallized by heating. The ratio of the number of tin atoms to the number of indium atoms in the ITO can be determined, for example, by determining the abundance ratio of indium atoms and tin atoms in the measurement object using X-ray photoelectron spectroscopy. The above-mentioned content ratio of tin oxide in the ITO can be determined, for example, from the abundance ratio of indium atoms and tin atoms thus determined. The above-mentioned content ratio of tin oxide in the ITO can also be determined from the tin oxide (SnO2) content ratio of the ITO target used during sputtering film formation.

[0030] The light-transmitting conductive layer 20 contains krypton (Kr) as rare gas atoms. In this embodiment, the rare gas atoms in the light-transmitting conductive layer 20 are derived from rare gas atoms used as a sputtering gas in a sputtering method described below for forming the light-transmitting conductive layer 20. In this embodiment, the light-transmitting conductive layer 20 is a film formed by a sputtering method (sputtered film).

[0031] The light-transmitting conductive layer 20 includes a region in the thickness direction D where the Kr content is preferably 1.0 atomic % or less, more preferably 0.7 atomic % or less, even more preferably 0.5 atomic % or less, particularly preferably 0.3 atomic % or less, very preferably 0.2 atomic % or less, and particularly preferably less than 0.1 atomic %. The Kr content in this region is, for example, 0.0001 atomic % or more. Preferably, the light-transmitting conductive layer 20 satisfies this Kr content throughout the entire thickness direction D. Specifically, the Kr content in the light-transmitting conductive layer 20 throughout the entire thickness direction D is preferably 1.0 atomic % or less, more preferably 0.7 atomic % or less, even more preferably 0.5 atomic % or less, particularly preferably 0.3 atomic % or less, very preferably 0.2 atomic % or less, and particularly preferably less than 0.1 atomic %. These configurations are suitable for realizing good crystal growth and forming large crystal grains when an amorphous light-transmitting conductive layer (light-transmitting conductive layer 20′ described below) is crystallized by heating to form the light-transmitting conductive layer 20 in the manufacturing process of the transparent conductive film X, and are therefore suitable for obtaining a light-transmitting conductive layer 20 with low resistance (the larger the crystal grains in the light-transmitting conductive layer 20, the lower the resistance of the light-transmitting conductive layer 20).

[0032] The presence or absence and content of rare gas atoms such as Kr in the light-transmitting conductive layer 20 can be identified, for example, by Rutherford backscattering spectrometry, which will be described later in the examples. The presence or absence of rare gas atoms such as Kr in the light-transmitting conductive layer 20 can be identified, for example, by X-ray fluorescence analysis, which will be described later in the examples. When the content of rare gas atoms in the light-transmitting conductive layer to be analyzed cannot be quantified by Rutherford backscattering spectrometry because it is below the detection limit (lower limit), and when the presence of rare gas atoms is identified by X-ray fluorescence analysis, the light-transmitting conductive layer is determined to include a region in which the content of rare gas atoms such as Kr is 0.0001 atomic % or more.

[0033] The Kr content in the light-transmitting conductive layer 20 may be non-uniform in the thickness direction D. For example, the Kr content may gradually increase or decrease with increasing distance from the transparent substrate 10 in the thickness direction D. Alternatively, in the thickness direction D, a partial region in which the Kr content gradually increases with increasing distance from the transparent substrate 10 may be located on the transparent substrate 10 side, and a partial region in which the Kr content gradually decreases with increasing distance from the transparent substrate 10 may be located on the opposite side from the transparent substrate 10. Alternatively, in the thickness direction D, a partial region in which the Kr content gradually decreases with increasing distance from the transparent substrate 10 may be located on the transparent substrate 10 side, and a partial region in which the Kr content gradually increases with increasing distance from the transparent substrate 10 may be located on the transparent substrate 10 side, and a partial region in which the Kr content gradually increases with increasing distance from the transparent substrate 10 may be located on the opposite side from the transparent substrate 10.

[0034] From the viewpoint of reducing compressive residual stress in the light-transmitting conductive layer 20, the light-transmitting conductive layer 20 preferably contains only Kr as rare gas atoms.

[0035] When the light-transmitting conductive layer 20 contains rare gas atoms other than Kr, examples of the rare gas atoms other than Kr include argon (Ar) and xenon (Xe). From the viewpoint of reducing the production cost of the transparent conductive film X, the light-transmitting conductive layer 20 preferably does not contain Xe.

[0036] The content of rare gas atoms (including Kr) in the light-transmitting conductive layer 20 is preferably 1.2 atomic % or less, more preferably 1.1 atomic % or less, even more preferably 1.0 atomic % or less, even more preferably 0.8 atomic % or less, even more preferably 0.5 atomic % or less, even more preferably 0.4 atomic % or less, very preferably 0.3 atomic % or less, and particularly preferably 0.2 atomic % or less throughout the thickness direction D. This configuration is suitable for achieving favorable crystal growth and forming large crystal grains when the amorphous light-transmitting conductive layer is crystallized by heating to form the light-transmitting conductive layer 20 during the manufacturing process of the transparent conductive film X, and is therefore suitable for obtaining a light-transmitting conductive layer 20 with low resistance. Furthermore, the light-transmitting conductive layer 20 includes a region in at least a portion of the thickness direction D where the rare gas atom content is, for example, 0.0001 atomic % or more. The rare gas atom content in the light-transmitting conductive layer 20 is preferably, for example, 0.0001 atomic % or more throughout the thickness direction D.

[0037] As illustrated in FIG. 2, the light-transmitting conductive layer 20 may contain Kr in a portion of its thickness direction D. FIG. 2A shows a light-transmitting conductive layer 20 including a first region 21 and a second region 22, in this order from the transparent substrate 10 side. The first region 21 contains Kr. The second region 22 does not contain Kr, but instead contains, for example, a rare gas atom other than Kr. FIG. 2B shows a light-transmitting conductive layer 20 including the second region 22 and the first region 21, in this order from the transparent substrate 10 side. Although the boundary between the first region 21 and the second region 22 is depicted by an imaginary line in FIG. 2, the boundary between the first region 21 and the second region 22 may not be clearly distinguishable in some cases, such as when the first region 21 and the second region 22 do not differ significantly in composition except for the rare gas atom content, which is trace.

[0038] When the light-transmitting conductive layer 20 includes the first region 21 and the second region 22, from the viewpoint of reducing the compressive residual stress in the light-transmitting conductive layer 20, the light-transmitting conductive layer 20 preferably includes the first region 21 (Kr-containing region) and the second region 22 (Kr-free region) in this order from the transparent substrate 10 side.

[0039] When the light-transmitting conductive layer 20 includes the first region 21 and the second region 22, the ratio of the thickness of the first region 21 to the total thickness of the first region 21 and the second region 22 is preferably 1% or more, more preferably 20% or more, even more preferably 30% or more, even more preferably 40% or more, and particularly preferably 50% or more. This ratio is less than 100%. Furthermore, the ratio of the thickness of the second region 22 to the total thickness of the first region 21 and the second region 22 is preferably 99% or less, more preferably 80% or less, even more preferably 70% or less, even more preferably 60% or less, and particularly preferably 50% or less. When the light-transmitting conductive layer 20 includes the first region 21 and the second region 22, this configuration regarding the respective thickness ratios of the first region 21 and the second region 22 is preferable from the viewpoint of reducing compressive residual stress in the light-transmitting conductive layer 20.

[0040] The Kr content in the first region 21 is preferably 1.0 atomic % or less, more preferably 0.7 atomic % or less, even more preferably 0.5 atomic % or less, even more preferably 0.3 atomic % or less, particularly preferably 0.2 atomic %, and particularly preferably less than 0.1 atomic % throughout the entire thickness direction D of the first region 21. Such a configuration is suitable for achieving good crystal growth and forming large crystal grains when the amorphous light-transmitting conductive layer is crystallized by heating to form the light-transmitting conductive layer 20 during the manufacturing process of the transparent conductive film X, and is therefore suitable for obtaining a low-resistance light-transmitting conductive layer 20. Furthermore, the Kr content in the first region 21 is, for example, 0.0001 atomic % or more throughout the entire thickness direction D of the first region 21.

[0041] Furthermore, the Kr content in the first region 21 may be non-uniform in the thickness direction D of the first region 21. For example, in the thickness direction D of the first region 21, the Kr content may gradually increase or decrease with increasing distance from the transparent substrate 10. Alternatively, in the thickness direction D of the first region 21, a partial region in which the Kr content gradually increases with increasing distance from the transparent substrate 10 may be located on the transparent substrate 10 side, and a partial region in which the Kr content gradually decreases with increasing distance from the transparent substrate 10 may be located on the opposite side from the transparent substrate 10. Alternatively, in the thickness direction D of the first region 21, a partial region in which the Kr content gradually decreases with increasing distance from the transparent substrate 10 may be located on the transparent substrate 10 side, and a partial region in which the Kr content gradually increases with increasing distance from the transparent substrate 10 may be located on the transparent substrate 10 side, and a partial region in which the Kr content gradually increases with increasing distance from the transparent substrate 10 may be located on the opposite side from the transparent substrate 10.

[0042] The thickness of the light-transmitting conductive layer 20 is, for example, 10 nm or more. The thickness of the light-transmitting conductive layer 20 is preferably 30 nm or more, more preferably 50 nm or more, even more preferably 80 nm or more, and particularly preferably 100 nm or more. Such a configuration is suitable for reducing the resistance of the light-transmitting conductive layer 20. The thickness of the light-transmitting conductive layer 20 is, for example, 1000 nm or less, preferably less than 300 nm, more preferably 250 nm or less, even more preferably 200 nm or less, particularly preferably 160 nm or less, particularly preferably less than 150 nm, and most preferably 148 nm or less. Such a configuration is suitable for reducing the compressive residual stress of the light-transmitting conductive layer 20 and suppressing warping of the transparent conductive film X.

[0043] The surface resistance of the light-transmitting conductive layer 20 is, for example, 200 Ω / □ or less, preferably 100 Ω / □ or less, more preferably 50 Ω / □ or less, even more preferably 20 Ω / □ or less, even more preferably 15 Ω / □ or less, and particularly preferably 13 Ω / □ or less. The surface resistance of the light-transmitting conductive layer 20 is, for example, 1 Ω / □ or more. These configurations regarding surface resistance are suitable for ensuring the low resistance required of the light-transmitting conductive layer 20 when the transparent conductive film X is provided in touch sensor devices, light control elements, photoelectric conversion elements, heat ray control elements, antenna elements, electromagnetic wave shielding elements, heater elements, lighting devices, image display devices, and the like. The surface resistance can be measured by a four-terminal method in accordance with JIS K7194.

[0044] The resistivity of the light-transmitting conductive layer 20 is preferably 2.2×10 -4 Ω·cm or less, preferably 2×10 -4 Ω·cm or less, more preferably 1.9×10 -4 Ω·cm or less, particularly preferably 1.8×10 -4 The resistivity of the light-transmitting conductive layer 20 is preferably 0.1×10 -4 Ω·cm or more, preferably 0.5×10 -4 Ω·cm or more, more preferably 1.0×10 -4 Ω·cm or more, more preferably 1.01×10 -4 The resistivity is Ω·cm or more. These resistivity configurations are suitable for ensuring the low resistivity required of the light-transmitting conductive layer 20 when the transparent conductive film X is included in touch sensor devices, light control elements, photoelectric conversion elements, heat-ray control elements, antenna elements, heater elements, electromagnetic wave shielding elements, lighting devices, image display devices, and the like. The resistivity is calculated by multiplying the surface resistance by the thickness. The resistivity can be controlled, for example, by adjusting the Kr content in the light-transmitting conductive layer 20 and adjusting various conditions for sputter-depositing the light-transmitting conductive layer 20. Such conditions include, for example, the temperature of the base (transparent substrate 10 in this embodiment) on which the light-transmitting conductive layer 20 is deposited, the amount of oxygen introduced into the deposition chamber, the air pressure in the deposition chamber, and the horizontal magnetic field strength above the target.

[0045] The total light transmittance (JIS K 7375-2008) of the light-transmitting conductive layer 20 is preferably 60% or more, more preferably 80% or more, and even more preferably 85% or more. Such a configuration is suitable for ensuring the transparency of the light-transmitting conductive layer 20. The total light transmittance of the light-transmitting conductive layer 20 is, for example, 100% or less.

[0046] The light-transmitting conductive layer 20 has a compressive residual stress of less than 490 MPa in its in-plane direction (orthogonal to the thickness direction D). That is, the compressive residual stress in at least one direction in the plane of the light-transmitting conductive layer 20 is less than 490 MPa. This compressive residual stress is preferably 480 MPa or less, more preferably 450 MPa or less, even more preferably less than 400 MPa, and particularly preferably 300 MPa or less. The compressive residual stress is, for example, 1 MPa or more. The one direction in which the compressive residual stress in the plane of the light-transmitting conductive layer 20 is less than 490 MPa is, for example, the TD direction (orthogonal to the MD direction) of the transparent substrate 10 or the transparent resin film 11. The compressive residual stress of the light-transmitting conductive layer 20 can be determined by the method described below in the examples.

[0047] The crystal grain size of the light-transmitting conductive layer 20 is preferably 40 nm or more, more preferably 50 nm or more, even more preferably 90 nm or more, particularly preferably 120 nm or more, and particularly preferably 150 nm or more. Such a configuration is suitable for reducing compressive residual stress in the light-transmitting conductive layer 20 and therefore suitable for suppressing warping of the transparent conductive film X. The crystal grain size of the light-transmitting conductive layer 20 is preferably 1000 nm or less, more preferably 500 nm or less, even more preferably 300 nm or less, particularly preferably 250 nm or less, and particularly preferably 200 nm or less. Such a configuration is suitable for suppressing cracks from occurring in the light-transmitting conductive layer 20 due to bending (bending or warping) of the transparent conductive film X. The crystal grain size of the light-transmitting conductive layer 20 refers to the average value of the circle-equivalent diameter determined by the method described below in the examples.

[0048] The average number of grain boundaries in the in-plane direction of the light-transmitting conductive layer 20 is preferably less than 12 / μm, more preferably 11 / μm or less, even more preferably 10 / μm or less, and particularly preferably 9 / μm or less. Such a configuration is suitable for reducing compressive residual stress in the light-transmitting conductive layer 20 and therefore suitable for suppressing warping of the transparent conductive film X. The average number of grain boundaries in the in-plane direction of the light-transmitting conductive layer 20 is preferably 2 / μm or more, more preferably 3 / μm or more, even more preferably 4 / μm or more, and particularly preferably 5 / μm or more. Such a configuration is suitable for suppressing cracks from occurring in the light-transmitting conductive layer 20 due to bending (bending or warping) of the transparent conductive film X. The average number of grain boundaries in the light-transmitting conductive layer 20 refers to the average number of grain boundaries determined by the method described below in the examples.

[0049] The crystalline nature of a light-transmitting conductive layer can be determined, for example, as follows. First, the light-transmitting conductive layer (in the case of transparent conductive film X, the light-transmitting conductive layer 20 on the transparent substrate 10) is immersed in 5% by mass hydrochloric acid at 20°C for 15 minutes. Next, the light-transmitting conductive layer is washed with water and then dried. Next, the resistance between a pair of terminals spaced 15 mm apart (terminal-to-terminal resistance) is measured on the exposed surface of the light-transmitting conductive layer (in the case of transparent conductive film X, the surface of the light-transmitting conductive layer 20 opposite the transparent substrate 10). If the terminal-to-terminal resistance is 10 kΩ or less, the light-transmitting conductive layer is crystalline. The crystalline nature of a light-transmitting conductive layer can also be determined by observing the presence of crystal grains in the light-transmitting conductive layer in a planar view using a transmission electron microscope. The preparation method and specific observation method for the observation sample used for this purpose are similar to those described below, for example, in relation to the method for deriving the crystal grain size in the light-transmitting conductive layer in the Examples.

[0050] The transparent conductive film X is produced, for example, as follows.

[0051] First, as shown in FIG. 3A, a transparent resin film 11 is prepared.

[0052] 3B, a functional layer 12 is formed on one surface of the transparent resin film 11 in the thickness direction D. By forming the functional layer 12 on the transparent resin film 11, a transparent substrate 10 is produced.

[0053] The functional layer 12 described above as a hard coat layer can be formed by applying a curable resin composition to the transparent resin film 11 to form a coating film, and then curing the coating film. When the curable resin composition contains an ultraviolet-curable resin, the coating film is cured by ultraviolet irradiation. When the curable resin composition contains a thermosetting resin, the coating film is cured by heating.

[0054] The exposed surface of the functional layer 12 formed on the transparent resin film 11 is subjected to a surface modification treatment as needed. When plasma treatment is used as the surface modification treatment, argon gas, for example, is used as an inert gas. The discharge power in the plasma treatment is, for example, 10 W or more and, for example, 5000 W or less.

[0055] Next, as shown in Fig. 3C, an amorphous light-transmitting conductive layer 20' is formed on the transparent substrate 10 (film formation process). Specifically, a material is deposited on the functional layer 12 of the transparent substrate 10 by sputtering to form the amorphous light-transmitting conductive layer 20'. The light-transmitting conductive layer 20' is an amorphous film that is both light-transmitting and conductive (the light-transmitting conductive layer 20' is converted into a crystalline light-transmitting conductive layer 20 by heating in the crystallization process described below).

[0056] In the sputtering method, it is preferable to use a sputtering deposition apparatus capable of performing a film formation process using a roll-to-roll method. When a roll-to-roll sputtering deposition apparatus is used in the production of the transparent conductive film X, a material is deposited on the long transparent substrate 10 while the transparent substrate 10 is running from a feed roll to a take-up roll provided in the apparatus, thereby forming the light-transmitting conductive layer 20'. In addition, in the sputtering method, a sputtering deposition apparatus having one deposition chamber may be used, or a sputtering deposition apparatus having multiple deposition chambers arranged in order along the running path of the transparent substrate 10 may be used (when forming the light-transmitting conductive layer 20' including the above-mentioned first region 21 and second region 22, a sputtering deposition apparatus having two or more deposition chambers is used).

[0057] Specifically, in the sputtering method, a sputtering gas (inert gas) is introduced into a deposition chamber of a sputtering deposition apparatus under vacuum conditions, while a negative voltage is applied to a target placed on a cathode in the deposition chamber. This generates a glow discharge, ionizing the gas atoms, causing the gas ions to collide with the target surface at high speed, ejecting the target material from the target surface, and depositing the ejected target material on the functional layer 12 of the transparent substrate 10.

[0058] The material of the target placed on the cathode in the film formation chamber is the conductive oxide described above for the light-transmitting conductive layer 20, preferably an indium-containing conductive oxide, and more preferably ITO. When ITO is used, the ratio of the tin oxide content to the total content of tin oxide and indium oxide in the ITO is preferably 0.1 mass% or more, more preferably 1 mass% or more, even more preferably 3 mass% or more, still more preferably 5 mass% or more, particularly preferably 7 mass% or more, and is preferably 15 mass% or less, more preferably 13 mass% or less, and even more preferably 12 mass% or less.

[0059] The sputtering method is preferably a reactive sputtering method, in which a reactive gas is introduced into the deposition chamber in addition to the sputtering gas.

[0060] When forming a light-transmitting conductive layer 20' containing Kr throughout the entire thickness direction D (first case), the gas introduced into one or more deposition chambers of the sputtering deposition apparatus contains Kr as a sputtering gas and oxygen as a reactive gas. The sputtering gas may contain an inert gas other than Kr. Examples of inert gases other than Kr include rare gas atoms other than Kr. Examples of rare gas atoms include Ar and Xe. When the sputtering gas contains an inert gas other than Kr, the content is preferably 80% by volume or less, more preferably 50% by volume or less.

[0061] When forming the light-transmitting conductive layer 20′ including the first region 21 and the second region 22 described above (second case), the gas introduced into the deposition chamber for forming the first region 21 contains Kr as a sputtering gas and oxygen as a reactive gas. The sputtering gas may contain an inert gas other than Kr. The type and content of the inert gas other than Kr are the same as those described above for the inert gas other than Kr in the first case.

[0062] In the second case, the gas introduced into the deposition chamber for forming the second region 22 contains an inert gas other than Kr as a sputtering gas and oxygen as a reactive gas. Examples of the inert gas other than Kr include the inert gases mentioned above as the inert gas other than Kr in the first case, and preferably Ar is used.

[0063] In the reactive sputtering method, the ratio of the amount of oxygen introduced to the total amount of sputtering gas and oxygen introduced into the film formation chamber is, for example, 0.01 flow % or more and, for example, 15 flow % or less.

[0064] The pressure in the film formation chamber during film formation by sputtering (sputter film formation) is, for example, 0.02 Pa or more and, for example, 1 Pa or less.

[0065] The temperature of the transparent substrate 10 during sputtering deposition is, for example, 100°C or lower. To suppress thermal expansion of the transparent substrate 10 during sputtering deposition, it is preferable to cool the transparent substrate 10. Suppressing thermal expansion of the transparent substrate 10 during sputtering deposition is useful for obtaining a light-transmitting conductive layer 20 (crystalline light-transmitting conductive layer) with suppressed compressive residual stress. From this perspective, the temperature of the transparent substrate 10 during sputtering deposition is preferably 20°C or lower, more preferably 10°C or lower, even more preferably 5°C or lower, and particularly preferably 0°C or lower, and is, for example, -50°C or higher, preferably -20°C or higher, more preferably -10°C or higher, and even more preferably -7°C or higher.

[0066] Examples of power sources for applying voltage to the target include DC power sources, AC power sources, MF power sources, and RF power sources. A combination of DC and RF power sources may be used. The absolute value of the discharge voltage during sputtering deposition is, for example, 50 V or more and, for example, 500 V or less. The horizontal magnetic field strength on the target surface is, for example, 10 mT or more, preferably 60 mT or more and, for example, 300 mT or less. This configuration is preferable for preventing excessive krypton atoms in the light-transmitting conductive layer 20 and, therefore, for preventing warpage in the light-transmitting conductive layer 20 and transparent conductive film X formed.

[0067] Next, in this manufacturing method, as shown in FIG. 3D, the light-transmitting conductive layer 20 is heated to convert it from amorphous to crystalline (crystallization) (crystallization step). Examples of heating methods include an infrared heater and an oven (heat medium heating oven, hot air heating oven). The heating environment may be either a vacuum environment or an atmospheric environment. Preferably, heating is performed in the presence of oxygen. To ensure a high crystallization rate, the heating temperature is, for example, 100°C or higher, preferably 120°C or higher. To suppress the influence of heating on the transparent substrate 10, the heating temperature is, for example, 200°C or lower, preferably 180°C or lower, more preferably 170°C or lower, and even more preferably 165°C or lower. The heating time is, for example, 10 hours or shorter, preferably 200 minutes or shorter, more preferably 90 minutes or shorter, and even more preferably 60 minutes or shorter, and for example, 1 minute or longer, preferably 5 minutes or longer.

[0068] After returning to room temperature after heating in this step, the transparent substrate 10 shrinks. The light-transmitting conductive layer 20 containing Kr is suitable for appropriately shrinking the light-transmitting conductive layer 20 on the shrinking transparent substrate 10 in the state after returning to room temperature (the preferred Kr content in the light-transmitting conductive layer 20 is as described above). The shrinkage of the light-transmitting conductive layer 20 after returning to room temperature helps to reduce compressive residual stress in the light-transmitting conductive layer 20.

[0069] In this manner, the transparent conductive film X is produced.

[0070] The light-transmitting conductive layer 20 in the transparent conductive film X may be patterned as shown schematically in FIG. 4. The light-transmitting conductive layer 20 can be patterned by etching the light-transmitting conductive layer 20 through a predetermined etching mask. The patterning of the light-transmitting conductive layer 20 may be performed before or after the crystallization step described above. The patterned light-transmitting conductive layer 20 functions as, for example, a wiring pattern.

[0071] In the transparent conductive film X, the light-transmitting conductive layer 20 on the transparent substrate 10 contains krypton and has a compressive residual stress of less than 490 MPa in the in-plane direction, and the compressive residual stress is preferably 480 MPa or less, more preferably 450 MPa or less, even more preferably less than 400 MPa, and particularly preferably 300 MPa or less. Such a configuration is suitable for reducing the resistance of the light-transmitting conductive layer 20 and suppressing warpage of the transparent conductive film X. Specific examples are shown in the examples and comparative examples below.

[0072] In the transparent conductive film X, the functional layer 12 may be an adhesion improving layer for realizing high adhesion of the light-transmitting conductive layer 20 to the transparent substrate 10. A configuration in which the functional layer 12 is an adhesion improving layer is suitable for ensuring adhesion between the transparent substrate 10 and the light-transmitting conductive layer 20.

[0073] The functional layer 12 may be an index-matching layer for adjusting the reflectance of the surface (one surface in the thickness direction D) of the transparent substrate 10. A configuration in which the functional layer 12 is an index-matching layer is suitable for making the pattern shape of the light-transmitting conductive layer 20 less visible when the light-transmitting conductive layer 20 on the transparent substrate 10 is patterned.

[0074] The functional layer 12 may be a release functional layer that enables practical peeling of the light-transmitting conductive layer 20 from the transparent substrate 10. A configuration in which the functional layer 12 is a release functional layer is suitable for peeling the light-transmitting conductive layer 20 from the transparent substrate 10 and transferring the light-transmitting conductive layer 20 to another member.

[0075] The functional layer 12 may be a composite layer in which multiple layers are connected in the thickness direction D. The composite layer preferably includes two or more layers selected from the group consisting of a hard coat layer, an adhesion improving layer, a refractive index adjusting layer, and a release functional layer. Such a configuration is suitable for the functional layer 12 to exhibit the above-mentioned functions of each selected layer in a composite manner. In one preferred embodiment, the functional layer 12 includes an adhesion improving layer, a hard coat layer, and a refractive index adjusting layer on the transparent resin film 11, in this order toward one side in the thickness direction D. In another preferred embodiment, the functional layer 12 includes a release functional layer, a hard coat layer, and a refractive index adjusting layer on the transparent resin film 11, in this order toward one side in the thickness direction D.

[0076] The transparent conductive film X is attached to an article and is used in a state where the light-transmitting conductive layer 20 is patterned as needed. The transparent conductive film X is attached to the article, for example, via an adhesive functional layer.

[0077] Examples of the article include an element, a member, and a device. That is, examples of the article with a transparent conductive film include an element with a transparent conductive film, a member with a transparent conductive film, and a device with a transparent conductive film.

[0078] Examples of elements include dimming elements and photoelectric conversion elements. Examples of dimming elements include current-driven dimming elements and electric field-driven dimming elements. Examples of current-driven dimming elements include electrochromic (EC) dimming elements. Examples of electric field-driven dimming elements include PDLC (polymer dispersed liquid crystal) dimming elements, PNLC (polymer network liquid crystal) dimming elements, and SPD (suspended particle device) dimming elements. Examples of photoelectric conversion elements include solar cells. Examples of solar cells include organic thin-film solar cells and dye-sensitized solar cells. Examples of components include electromagnetic wave shielding members, heat ray control members, heater members, and antenna members. Examples of devices include touch sensor devices, lighting devices, and image display devices.

[0079] Examples of the fixing functional layer include a pressure-sensitive adhesive layer and an adhesive layer. The material for the fixing functional layer is not particularly limited as long as it is transparent and exhibits a fixing function. The fixing functional layer is preferably formed from a resin. Examples of resins include acrylic resin, silicone resin, polyester resin, polyurethane resin, polyamide resin, polyvinyl ether resin, vinyl acetate / vinyl chloride copolymer, modified polyolefin resin, epoxy resin, fluororesin, natural rubber, and synthetic rubber. Acrylic resin is preferred as the resin because it exhibits adhesive properties such as cohesion, adhesion, and moderate wettability, is excellent in transparency, and has excellent weather resistance and heat resistance.

[0080] The adhesive layer (the resin forming the adhesive layer) may contain a corrosion inhibitor to inhibit corrosion of the light-transmitting conductive layer 20. The adhesive layer (the resin forming the adhesive layer) may contain a migration inhibitor (such as a material disclosed in JP 2015-022397 A) to inhibit migration of the light-transmitting conductive layer 20. The adhesive layer (the resin forming the adhesive layer) may also contain an ultraviolet absorber to inhibit deterioration during outdoor use of the article. Examples of ultraviolet absorbers include benzophenone compounds, benzotriazole compounds, salicylic acid compounds, oxalic acid anilide compounds, cyanoacrylate compounds, and triazine compounds.

[0081] Furthermore, when the transparent substrate 10 of the transparent conductive film X is fixed to an article via an adhesive functional layer, the light-transmitting conductive layer 20 (including the light-transmitting conductive layer 20 after patterning) is exposed in the transparent conductive film X. In such a case, a cover layer may be disposed on the exposed surface of the light-transmitting conductive layer 20. The cover layer is a layer that covers the light-transmitting conductive layer 20, improving the reliability of the light-transmitting conductive layer 20 and suppressing functional deterioration of the light-transmitting conductive layer 20 due to damage. Such a cover layer is preferably formed from a dielectric material, more preferably from a composite material of a resin and an inorganic material. Examples of resins include the resins described above for the adhesive functional layer. Examples of inorganic materials include inorganic oxides and fluorides. Examples of inorganic oxides include silicon oxide, titanium oxide, niobium oxide, aluminum oxide, zirconium dioxide, and calcium oxide. Examples of fluorides include magnesium fluoride. The cover layer (a mixture of resin and inorganic material) may also contain the above-mentioned corrosion inhibitor, migration inhibitor, and ultraviolet absorber.

[0082] Because the light-transmitting conductive layer 20 of the transparent conductive film X included in the article is suitable for reducing resistance, the article is suitable for achieving high performance in terms of functions that depend on the light transparency and conductivity of the light-transmitting conductive layer 20. Furthermore, because the transparent conductive film X included in the article is suitable for suppressing warping, the article is suitable for appropriately assembling the transparent conductive film X with high positional accuracy, for example, during the manufacturing process. [Example]

[0083] The present invention will be specifically described below with reference to examples. The present invention is not limited to these examples. The specific numerical values ​​of the blending amounts (contents), physical property values, parameters, etc. described below can be substituted for the upper limits (numerical values ​​defined as "equal to or less than") or lower limits (numerical values ​​defined as "equal to or more than") of the corresponding blending amounts (contents), physical property values, parameters, etc. described in the above-mentioned "Description of the Invention."

[0084] Example 1 A long PET film with a hard coat layer on both sides (product name "KB Film CANIA", thickness 54 μm, manufactured by Kimoto Co., Ltd.) was prepared as a transparent substrate (after heating this transparent substrate at 165°C for 1 hour, the thermal shrinkage rate of the transparent substrate in the direction in which it shrinks the most (maximum thermal shrinkage rate, in this example, the thermal shrinkage rate in the MD direction) was 0.65%).

[0085] Next, a 130 nm thick amorphous light-transmitting conductive layer was formed on the hard coat layer of the transparent substrate by reactive sputtering (film formation process). In the reactive sputtering, a sputtering film formation device (DC magnetron sputtering device) capable of performing a film formation process by a roll-to-roll method was used. The sputtering film formation conditions in this example are as follows:

[0086] The target used was a sintered body of indium oxide and tin oxide (tin oxide concentration: 10% by mass). A DC power supply was used as the power source for applying voltage to the target. The horizontal magnetic field strength above the target was 90 mT. The film formation temperature (the temperature of the transparent substrate on which the light-transmitting conductive layer is laminated) was -5°C. The ultimate vacuum in the film formation chamber of the device was 0.8 x 10 -4 After evacuating the film formation chamber to a pressure of 0.2 Pa, Kr as a sputtering gas and oxygen as a reactive gas were introduced into the film formation chamber, and the pressure in the film formation chamber was set to 0.2 Pa. The ratio of the amount of oxygen introduced to the total amount of Kr and oxygen introduced into the film formation chamber was about 2.5 flow %. As shown in FIG. 5, the amount of oxygen introduced was within region R of the resistivity-oxygen introduction amount curve, and the resistivity of the formed film was 6.5×10 -4 The resistivity vs. oxygen introduction amount curve shown in Figure 5 was created by investigating in advance the dependence of the resistivity of the optically transparent conductive layer on the amount of oxygen introduced when the optically transparent conductive layer was formed by reactive sputtering under the same conditions as above, except for the amount of oxygen introduced.

[0087] Next, the light-transmitting conductive layer on the transparent substrate was crystallized by heating in a hot air oven (crystallization step). In this step, the heating temperature was 165° C. and the heating time was 1 hour.

[0088] In this way, a transparent conductive film was produced in Example 1. The light-transmitting conductive layer (thickness: 130 nm, crystalline) of the transparent conductive film in Example 1 was composed of a single Kr-containing ITO layer.

[0089] Example 2 Except for changing some of the film-forming conditions in the film-forming step and changing the heating conditions in the crystallization step, the transparent conductive film of Example 2 was produced in the same manner as the transparent conductive film of Example 1. In the film-forming step in this example, the pressure in the film-forming chamber was set to 0.6 Pa, the thickness of the light-transmitting conductive layer to be formed was set to 34 nm, and the specific resistance of the light-transmitting conductive layer was set to 5.7 × 10 -4The amount of oxygen introduced was adjusted to achieve a resistivity of Ω·cm. In the crystallization step in this example, the heating temperature was 140° C. and the heating time was 5 hours.

[0090] The light-transmitting conductive layer (thickness: 34 nm, crystalline) of the transparent conductive film of Example 2 is composed of a single Kr-containing ITO layer.

[0091] Example 3 The transparent conductive film of Example 3 was produced in the same manner as the transparent conductive film of Example 1, except that in the film formation process, a first sputtering film formation was carried out to form a first region (thickness 50 nm) of the light-transmitting conductive layer on the transparent substrate, and a second sputtering film formation was carried out to form a second region (thickness 80 nm) of the light-transmitting conductive layer on the first region, sequentially.

[0092] The conditions for the first sputtering film formation in this example were as follows: A sintered body of indium oxide and tin oxide (tin oxide concentration: 10 mass %) was used as the target; a DC power supply was used as the power source for applying voltage to the target; the horizontal magnetic field strength above the target was 90 mT; the film formation temperature was -5°C; and the ultimate vacuum in the first film formation chamber of the apparatus was 0.8 x 10 -4 After evacuating the first film formation chamber until the pressure reached 0.2 Pa, Kr as a sputtering gas and oxygen as a reactive gas were introduced into the first film formation chamber, and the pressure in the film formation chamber was set to 0.2 Pa. The amount of oxygen introduced into the film formation chamber was adjusted so that the resistivity of the film formed would be 6.5 × 10 -4 The resistance was adjusted to Ω·cm.

[0093] The conditions for the second sputtering film formation in this example are as follows: the ultimate vacuum in the second film formation chamber of the apparatus is 0.8×10 -4 After the second film formation chamber was evacuated to a vacuum until the pressure reached 0.4 Pa, Ar as a sputtering gas and oxygen as a reactive gas were introduced into the second film formation chamber, and the pressure inside the film formation chamber was set to 0.4 Pa. In this example, the other conditions in the second sputter formation were the same as those in the first sputter formation.

[0094] In this manner, a transparent conductive film of Example 3 was produced. The light-transmitting conductive layer (thickness 130 nm, crystalline) of the transparent conductive film of Example 3 had, from the transparent substrate side, a first region (thickness 50 nm) made of a Kr-containing ITO layer and a second region (thickness 80 nm) made of an Ar-containing ITO layer.

[0095] [Examples 4 and 5] The transparent conductive films of Examples 4 and 5 were produced in the same manner as the transparent conductive film of Example 3, except that the thickness of the first region of the light-transmitting conductive layer formed in the film formation process was changed from 50 nm to 66 nm (Example 4) or 85 nm (Example 5), and the thickness of the second region was changed from 80 nm to 64 nm (Example 4) or 45 nm (Example 5).

[0096] The light-transmitting conductive layer (thickness 130 nm, crystalline) of the transparent conductive film of Example 4 has, from the transparent substrate side, a first region (thickness 66 nm) made of a Kr-containing ITO layer and a second region (thickness 64 nm) made of an Ar-containing ITO layer.The light-transmitting conductive layer (thickness 130 nm) of the transparent conductive film of Example 5 has, from the transparent substrate side, a first region (thickness 85 nm) made of a Kr-containing ITO layer and a second region (thickness 45 nm) made of an Ar-containing ITO layer.

[0097] Example 6 The transparent conductive film of Example 6 was produced in the same manner as the transparent conductive film of Example 1, except for the following in the sputtering film formation: A mixed gas of krypton and argon (Kr 90% by volume, Ar 10% by volume) was used as the sputtering gas. The ratio of the amount of oxygen introduced to the total amount of the mixed gas and oxygen introduced into the film formation chamber was set to about 2.7 flow rate %, and the amount of oxygen introduced was set so that the resistivity of the formed film was 5.7 × 10 -4 The resistivity was adjusted to Ω·cm. The thickness of the light-transmitting conductive layer formed was 140 nm.

[0098] The light-transmitting conductive layer (thickness: 140 nm, crystalline) of the transparent conductive film of Example 6 was composed of a single ITO layer containing Kr and Ar.

[0099] Comparative Example 1 The transparent conductive film of Comparative Example 1 was produced in the same manner as the transparent conductive film of Example 1, except that in the film formation process, Ar was used instead of Kr as the sputtering gas and the film formation pressure was changed from 0.2 Pa to 0.4 Pa. The light-transmitting conductive layer (thickness 130 nm, crystalline) of the transparent conductive film of Comparative Example 1 consisted of a single Ar-containing ITO layer.

[0100] Comparative Example 2 The transparent conductive film of Comparative Example 2 was produced in the same manner as the transparent conductive film of Example 1, except that in the film formation step, Ar was used as the sputtering gas instead of Kr, the film formation pressure was changed from 0.2 Pa to 0.4 Pa, and in the crystallization step, the heating temperature was changed from 165°C to 155°C. The light-transmitting conductive layer (thickness 130 nm, crystalline) of the transparent conductive film of Comparative Example 2 consisted of a single Ar-containing ITO layer.

[0101] Comparative Example 3 The transparent conductive film of Comparative Example 3 was produced in the same manner as the transparent conductive film of Example 3, except that in the film formation process, a first sputtering film formation was performed in which a second region (75 nm thick) of the light-transmitting conductive layer was formed on the transparent substrate, and a second sputtering film formation was performed in which a first region (45 nm thick) of the light-transmitting conductive layer was formed on the second region. The conditions for the first sputtering film formation in this comparative example were the same as the conditions for the second sputtering film formation in Example 3. The conditions for the second sputtering film formation in this comparative example were the same as the conditions for the first sputtering film formation in Example 3.

[0102] The light-transmitting conductive layer (thickness 120 nm, crystal chamber) of the transparent conductive film of Comparative Example 3 has, from the transparent substrate side, a second region (thickness 75 nm) consisting of an Ar-containing ITO layer and a first region (thickness 45 nm) consisting of a Kr-containing ITO layer.

[0103] <Thickness of Light-Transmitting Conductive Layer> The thickness of the light-transmitting conductive layer of each transparent conductive film in Examples 1 to 6 and Comparative Examples 1 to 3 was measured by FE-TEM observation. Specifically, first, a cross-sectional observation sample of each light-transmitting conductive layer in Examples 1 to 6 and Comparative Examples 1 to 3 was prepared by FIB microsampling. In the FIB microsampling method, an FIB device (trade name "FB2200", manufactured by Hitachi) was used, and the acceleration voltage was set to 10 kV. Next, the thickness of the light-transmitting conductive layer in the cross-sectional observation sample was measured by FE-TEM observation. In the FE-TEM observation, an FE-TEM device (trade name "JEM-2800", manufactured by JEOL) was used, and the acceleration voltage was set to 200 kV.

[0104] The thickness of the first region of each light-transmitting conductive layer in Examples 3 to 5 was measured by FE-TEM observation of a cross-sectional observation sample prepared from an intermediate product before the second region was formed on the first region. The thickness of the second region of each light-transmitting conductive layer in Examples 3 to 5 was determined by subtracting the thickness of the first region from the total thickness of the light-transmitting conductive layer in Examples 3 to 5. The proportion of the first region in the thickness direction of the light-transmitting conductive layer was 38.5% in Example 3, 50.8% in Example 4, and 65.4% in Example 5.

[0105] The thickness of the second region of the light-transmitting conductive layer in Comparative Example 3 was measured by FE-TEM observation of a cross-sectional observation sample prepared from an intermediate product before the first region was formed on the second region. The thickness of the first region of the light-transmitting conductive layer in Comparative Example 3 was determined by subtracting the thickness of the second region from the total thickness of the light-transmitting conductive layer in Comparative Example 3. The proportion of the first region in the thickness direction of the light-transmitting conductive layer in Comparative Example 3 was 37.5%.

[0106] <Specific resistance> The resistivity of the light-transmitting conductive layer was examined for each of the transparent conductive films of Examples 1 to 6 and Comparative Examples 1 to 3. Specifically, the surface resistance of the light-transmitting conductive layer of the transparent conductive film was measured using a four-terminal method in accordance with JIS K 7194 (1994), and then the resistivity (Ω·cm) was calculated by multiplying the surface resistance value by the thickness of the light-transmitting conductive layer. The results are shown in Table 1.

[0107] <Warpage of transparent conductive film> The degree of warping was examined for each of the transparent conductive films of Examples 1 to 6 and Comparative Examples 1 to 3 as follows. First, three rectangular samples (10 cm × 10 cm) were cut out from each transparent conductive film. Next, each sample was placed on the mounting surface (a substantially horizontal surface) of a mounting table, and the distance from the mounting surface was measured for each of the four vertices at the sample's four corners. Specifically, when the sample was placed on the mounting surface so that the transparent substrate side of the sample was in contact with the mounting surface, the vertical distance (mm) between the vertex that was farther from the mounting surface and the mounting surface was measured as a positive value. Furthermore, when the sample was placed on the mounting surface so that the light-transmitting conductive layer side of the sample was in contact with the mounting surface, the vertical distance (mm) between the vertex that was farther from the mounting surface and the mounting surface was measured as a negative value. The distance between the vertex that was not far from the mounting surface and the mounting surface was 0 mm. Next, the absolute value of the average of the measured distances for a total of 12 vertices of each transparent conductive film was calculated as the average warping amount (mm). The values ​​are shown in Table 1. In each of the transparent conductive films of Comparative Examples 1 and 2, the measurement sample had a cylindrically curved shape (a shape in which the light-transmitting conductive layer was located on the outside and the transparent substrate was located on the inside), and the amount of warpage could not be measured.

[0108] Quantitative analysis of rare gas atoms in a light-transmitting conductive layer The contents of Kr and Ar atoms in the light-transmitting conductive layer of each of the transparent conductive films in Examples 1 to 6 and Comparative Examples 1 to 3 were analyzed by Rutherford backscattering spectroscopy (RBS). The contents (atomic %) of Kr and Ar atoms in the light-transmitting conductive layer were determined by calculating the elemental ratios of the five elements detected: In+Sn (since it is difficult to measure In and Sn separately using Rutherford backscattering spectroscopy, they were evaluated as the sum of the two elements), O, Ar, and Kr. The equipment and measurement conditions used are as follows. The analytical results, including the Kr content (atomic %), Ar content (atomic %), and rare gas atom content (atomic %), are listed in Table 1. Regarding the analysis of the Kr content, reliable measurements above the detection limit (lower limit) were not obtained in Examples 1 to 6 and Comparative Example 3 (the detection limit may vary depending on the thickness of the light-transmitting conductive layer used for measurement). Therefore, in Table 1, the Kr content in the light-transmitting conductive layer is expressed as "<specific detection limit value for the thickness of the light-transmitting conductive layer subjected to measurement" to indicate that it is below the detection limit value for the thickness of the layer (the same applies to the expression of the rare gas atom content).

[0109] <Equipment used> Pelletron 3SDH (manufactured by National Electrostatics Corporation) <Measurement conditions> Incident ions: 4 He ++ Incident energy: 2300 keV Incident angle: 0deg Scattering angle: 160deg Specimen current: 6nA Beam diameter: 2mmφ In-plane rotation: None Irradiation dose: 75μC

[0110] <Confirmation of Kr atoms in the light-transmitting conductive layer> The inclusion of Kr atoms in each of the light-transmitting conductive layers in Examples 1 to 6 and Comparative Example 3 was confirmed as follows. First, using a scanning X-ray fluorescence analyzer (trade name "ZSX PrimusIV", manufactured by Rigaku Corporation), X-ray fluorescence analysis measurements were repeated five times under the following measurement conditions, and the average value for each scanning angle was calculated to create an X-ray spectrum. Then, by confirming that a peak appeared near a scanning angle of 28.2° in the created X-ray spectrum, it was confirmed that Kr atoms were included in the light-transmitting conductive layer.

[0111] <Measurement conditions> Spectrum; Kr-KA Measuring diameter: 30 mm Atmosphere: Vacuum Target: Rh Tube voltage: 50kV Tube current: 60mA Primary filter: Ni40 Scanning angle (deg): 27.0~29.5 Step (deg): 0.020 Speed ​​(deg / min): 0.75 Attenuator: 1 / 1 Slit: S2 Spectroscopic crystal: LiF(200) Detector: SC PHA: 100-300

[0112] <Average Crystal Grain Size of Light-Transmitting Conductive Layer> The average crystal grain size in plan view in the light-transmitting conductive layer (crystalline ITO film) was examined for each of the transparent conductive films of Examples 1 to 6 and Comparative Examples 1 to 3. Specifically, a film piece cut from the transparent conductive film was first fixed to a sample holder of an ultramicrotome. Next, the cutting edge of a microtome knife was applied to the film surface of the light-transmitting conductive layer in the film piece at an extremely acute angle, and the light-transmitting conductive layer was cut with the microtome knife so as to generate a cut surface approximately parallel to the film surface, thereby obtaining an observation sample. Next, the observation sample was observed using a transmission electron microscope, and a planar image of the observation sample was taken at a magnification that allowed clear observation of the crystal grains (direct magnification: 100,000x or 200,000x). Next, a number of crystal grains ranging from 110 to 250 were arbitrarily selected from the numerous crystal grains in the photographed image. Next, the captured images were analyzed to determine the area of ​​each region defined by the grain boundaries (intra-grain boundary regions) from the number of pixels present in that region, and the diameter of a circle with the same area as that region was calculated as the grain size (equivalent circle diameter).Then, the average value of the equivalent circle diameters of the selected multiple grains was calculated.These values ​​are shown in Table 1.

[0113] <Average number of grain boundaries in the light-transmitting conductive layer> The average number of grain boundaries in the light-transmitting conductive layer (crystalline ITO film) was examined for each of the transparent conductive films of Examples 1 to 6 and Comparative Examples 1 to 3. Specifically, the above-mentioned image obtained for each transparent conductive film was first printed on paper to examine the crystal grain size. Next, five line segments, each corresponding to an actual size of 1.0 μm, were drawn at random locations on the printed image. Next, the number of grain boundaries present within each line segment was counted, and the average number of grain boundaries in the five line segments was calculated as the average number of grain boundaries (numbers / μm). The values ​​are listed in Table 1.

[0114] <Compressive Residual Stress in Light-Transmitting Conductive Layer> The compressive residual stress of the light-transmitting conductive layer (crystalline ITO film) of each of the transparent conductive films in Examples 1 to 6 and Comparative Examples 1 to 3 was indirectly determined from the crystal lattice distortion of the light-transmitting conductive layer. Specifically, this is as follows.

[0115] First, a rectangular measurement sample (50 mm × 50 mm) was cut out from the transparent conductive film. Next, using a powder X-ray diffractometer (product name "SmartLab", manufactured by Rigaku Corporation), the diffraction intensity of the measurement sample was measured at 0.02° intervals over a scattering angle 2θ range of 60 to 61.6° (0.15° / min). Next, based on the peak angle 2θ of the obtained diffraction image (peak of the ITO (622) plane) and the wavelength λ of the X-ray source, the crystal lattice spacing d of the light-transmitting conductive layer in the measurement sample was calculated, and the lattice strain ε was calculated based on d. The following formula (1) was used to calculate d, and the following formula (2) was used to calculate ε.

[0116]

number

[0117] In equations (1) and (2), λ is the wavelength (= 0.15418 nm) of the X-ray source (Cu Kα radiation), and d0 is the lattice spacing (= 0.1518967 nm) of stress-free ITO. The above X-ray diffraction measurements were performed for angles Ψ between the film surface normal and the ITO crystal plane normal of 65°, 70°, 75°, and 85°, and the lattice strain ε at each Ψ was calculated. The angle Ψ between the film surface normal and the ITO crystal plane normal was adjusted by rotating the measurement sample (part of a transparent conductive film) around the MD direction (direction perpendicular to the TD direction) of the transparent substrate as the rotation axis. The residual stress σ in the ITO film plane direction was calculated as Sin 2 The relationship between Ψ and lattice strain ε was plotted and the slope of the line was calculated using the following formula (3): The residual stress σ in the TD direction calculated in this way is shown in Table 1 as compressive residual stress (MPa).

[0118]

number

[0119] In equation (3), E is the Young's modulus of ITO (=115 GPa), and ν is the Poisson's ratio of ITO (=0.35).

[0120] [Table 1] [Industrial Applicability]

[0121] The transparent conductive film of the present invention can be used as a supply material for a conductive film for patterning transparent electrodes in various devices such as liquid crystal displays, touch panels, and optical sensors. [Explanation of symbols]

[0122] X Transparent conductive film D thickness direction 10 Transparent base material 11 Transparent resin film 12 Functional Layers 20 Light-transparent conductive layer 21 First area 22 Second area

Claims

1. a transparent substrate and a light-transmitting conductive layer in this order in a thickness direction; the transparent substrate includes a flexible transparent resin film, the light-transmitting conductive layer contains krypton; the light-transmitting conductive layer has a compressive residual stress of less than 490 MPa in an in-plane direction perpendicular to the thickness direction, A transparent conductive film, wherein the light-transmitting conductive layer is a glow discharge sputtered film.

2. The transparent conductive film according to claim 1 , wherein the average number of grain boundaries in the in-plane direction of the light-transmitting conductive layer is less than 12 / μm.

3. The transparent conductive film according to claim 1 or 2, wherein the light-transmitting conductive layer contains an indium-containing conductive oxide.

4. The transparent conductive film according to claim 1 , wherein the light-transmitting conductive layer does not contain xenon.

5. The light-transmitting conductive layer has a thickness of 2.2×10 －４ The transparent conductive film according to claim 1 , which has a resistivity of Ω·cm or less.

6. The transparent conductive film according to claim 1 , wherein the light-transmitting conductive layer has a thickness of 30 nm or more.

7. A method for manufacturing a semiconductor device, comprising: a film-forming step of forming an amorphous light-transmitting conductive layer on a transparent substrate by a sputtering method that generates glow discharge; a crystallization step of converting the amorphous light-transmitting conductive layer into a crystalline light-transmitting conductive layer by heating; the transparent substrate includes a flexible transparent resin film, the light-transmitting conductive layer contains krypton; The method for producing a transparent conductive film, wherein the light-transmitting conductive layer has a compressive residual stress of less than 490 MPa in an in-plane direction perpendicular to the thickness direction.

8. The method for producing a transparent conductive film according to claim 7 , wherein the average number of grain boundaries in an in-plane direction of the light-transmitting conductive layer is less than 12 / μm.

9. The method for producing a transparent conductive film according to claim 7 or 8, wherein the light-transmitting conductive layer contains an indium-containing conductive oxide.

10. The method for producing a transparent conductive film according to claim 7 , wherein the light-transmitting conductive layer does not contain xenon.

11. The light-transmitting conductive layer has a thickness of 2.2×10 －４ The method for producing a transparent conductive film according to claim 7 , wherein the transparent conductive film has a specific resistance of Ω·cm or less.

12. The method for producing a transparent conductive film according to claim 7 , wherein the light-transmitting conductive layer has a thickness of 30 nm or more.

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