Transparent conductive film, and method for manufacturing a transparent conductive film

Description

[Technical Field]

[0001] This invention relates to a transparent conductive film and a method for manufacturing a transparent conductive film. [Background technology]

[0002] Conventionally, transparent conductive films are known that have a transparent resin substrate film and a transparent conductive layer arranged sequentially in the thickness direction. The transparent 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. In the process of forming the transparent conductive layer, for example, first, an amorphous film of transparent conductive material is formed on the substrate film by sputtering (film formation process). Next, the amorphous transparent conductive layer on the substrate film is crystallized by heating (crystallization process). Technology related to such transparent conductive films is described, for example, in Patent Document 1 below. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-71850 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] During the crystallization process, thermal expansion or contraction occurs in each component of the transparent conductive film. Conventionally, due to the thermal expansion or contraction of each component, cracks occur in thin and brittle transparent conductive layers. The occurrence of cracks in the transparent conductive layer is undesirable, for example, from the viewpoint of the conductivity of the transparent conductive layer.

[0005] The present invention provides a transparent conductive film suitable for obtaining a transparent conductive film having a crystalline transparent conductive layer in which crack formation is suppressed, and a method for manufacturing a transparent conductive film. [Means for solving the problem]

[0006] The present invention [1] provides a transparent conductive film comprising a transparent resin substrate and a transparent conductive layer in this order in the thickness direction, wherein in an in-plane direction perpendicular to the thickness direction, there is a first direction in which the thermal shrinkage rate by heat treatment under heating conditions of 165°C and 60 minutes is maximum, and a second direction perpendicular to the first direction, wherein the first thermal shrinkage rate T1 of the transparent conductive film in the second direction by heat treatment under the heating conditions, and the second thermal shrinkage rate T2 of the transparent resin substrate in the second direction by heat treatment under the heating conditions satisfy |T1-T2|<0.12%.

[0007] The present invention [2] includes the transparent conductive film described in [1] above, wherein the transparent conductive layer contains krypton.

[0008] The present invention [3] includes the transparent conductive film described in [1] or [2] above, wherein the transparent conductive layer is amorphous.

[0009] The present invention [4] includes a method for producing a transparent conductive film, comprising the steps of preparing the transparent conductive film described in [3] above and heating the transparent conductive layer to crystallize it. [Effects of the Invention]

[0010] The transparent conductive film of the present invention satisfies the condition that the first thermal shrinkage rate T1 and the second thermal shrinkage rate T2 in the transparent conductive layer satisfy |T1-T2|<0.12%. Therefore, this transparent conductive film is suitable for suppressing the generation of excessive internal stress (e.g., compressive or tensile stress in the in-plane direction) in the transparent conductive layer after heating for crystallization, for example. Such a transparent conductive film is suitable for obtaining a transparent conductive film having a crystalline transparent conductive layer in which crack formation is suppressed. The method for manufacturing the transparent conductive film of the present invention is suitable for obtaining a transparent conductive film having a crystalline transparent conductive layer in which crack formation is suppressed from such a transparent conductive film. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view of an embodiment of the transparent conductive film of the present invention. [Figure 2] This is a schematic cross-sectional view of a modified example of the transparent conductive film of the present invention. [Figure 3] It represents the manufacturing method of the transparent conductive film shown in FIG. 1. FIG. 3A represents the step of preparing a resin film, FIG. 3B represents the step of forming a functional layer on the resin film, and FIG. 3C represents the step of forming a transparent conductive layer on the functional layer. [Figure 4] In the transparent conductive film shown in FIG. 1, it represents the case where the transparent conductive layer is patterned. [Figure 5] In the transparent conductive film shown in FIG. 1, it represents the case where the amorphous transparent conductive layer is converted into a crystalline transparent conductive layer. [Figure 6] It is a graph showing the relationship between the amount of oxygen introduced when forming the transparent conductive layer by the sputtering method and the specific resistance of the formed transparent conductive layer.

Embodiments for Carrying Out the Invention

[0012] FIG. 1 is a schematic cross-sectional view of a transparent conductive film X which is an embodiment of the transparent conductive film of the present invention. The transparent conductive film X includes a transparent resin substrate 10 and a transparent conductive layer 20 in this order toward one side in the thickness direction H. The transparent conductive film X, the transparent resin substrate 10, and the transparent conductive layer 20 each have a shape that spreads in a direction (plane direction) orthogonal to the thickness direction H. The transmissive conductive film X is an element provided in a touch sensor, a light control element, a photoelectric conversion element, a heat ray control member, an antenna member, an electromagnetic wave shield member, a heater member, a lighting device, an image display device, and the like.

[0013] In the present embodiment, the transparent resin substrate 10 includes a resin film 11 and a functional layer 12 in this order toward one side in the thickness direction H.

[0014] The resin film 11 is a flexible, transparent resin film. Examples of materials for the 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 (COP). Examples of acrylic resins include polymethacrylate. From the viewpoint of transparency and strength, the material for the resin film 11 is preferably at least one selected from the group consisting of polyester resin and polyolefin resin, and more preferably at least one selected from the group consisting of COP and PET.

[0015] The surface of the resin film 11 facing the functional layer 12 may be surface modified. Examples of surface modification treatments include corona treatment, plasma treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment.

[0016] The thickness of the 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 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 resin film 11 are suitable for ensuring the handling of the transparent conductive film X.

[0017] The total light transmittance of the resin film 11 (JIS K 7375-2008) 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 for the transparent conductive film X when it is provided in touch sensors, dimming elements, photoelectric conversion elements, heat control members, antenna members, electromagnetic wave shielding members, heater members, lighting devices, and image display devices, etc. The total light transmittance of the resin film 11 is, for example, 100% or less.

[0018] In this embodiment, the functional layer 12 is located on one surface of the resin film 11 in the thickness direction H. 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 Figure 1) of the transparent conductive layer 20.

[0019] 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 curable resin compositions include ultraviolet-curable resin compositions and thermosetting resin compositions. From the viewpoint of improving the manufacturing 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. A specific example of an ultraviolet-curable resin composition is the hard coat layer forming composition described in Japanese Patent Application Publication No. 2016-179686.

[0020] The curable resin composition may contain fine particles. The incorporation of fine particles into the curable resin composition helps to adjust the hardness, surface roughness, and refractive index of the functional layer 12.

[0021] Examples of fine particles include metal oxide particles, glass particles, and organic particles. Examples of materials for metal oxide particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of materials for organic particles include polymethyl methacrylate, polystyrene, polyurethane, acrylic-styrene copolymer, benzoguanamine, melamine, and polycarbonate.

[0022] The incorporation of fine particles into the curable resin composition helps to adjust the hardness, surface roughness, and refractive index of the functional layer 12.

[0023] The thickness of the functional layer 12 as a hard coat layer is preferably 0.1 μm or more, more preferably 0.3 μm or more, and even more preferably 0.5 μm or more. Such a configuration is suitable for achieving sufficient abrasion resistance in the transparent 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 surface of the functional layer 12 facing the transparent conductive layer 20 may be surface modified. Examples of surface modification treatments include corona treatment, plasma treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment.

[0025] The thickness of the transparent resin 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 resin 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 resin substrate 10 are suitable for ensuring the handling of the transparent conductive film X.

[0026] The total light transmittance (JIS K 7375-2008) of the transparent resin 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 for the transparent conductive film X when the transparent conductive film X is provided in touch sensors, dimming elements, photoelectric conversion elements, heat control members, antenna members, electromagnetic wave shielding members, heater members, lighting devices, and image display devices, etc. The total light transmittance of the transparent resin substrate 10 is, for example, 100% or less.

[0027] In this embodiment, the transparent conductive layer 20 is located on one surface of the transparent resin substrate 10 in the thickness direction H. In this embodiment, the transparent conductive layer 20 is an amorphous film that combines light transmittance and conductivity. The amorphous transparent conductive layer 20 is converted into a crystalline transparent conductive layer (transparent conductive layer 20' described later) by heating, and its resistivity decreases.

[0028] The transparent conductive layer 20 is a layer formed from a light-transmitting conductive material. The light-transmitting conductive material contains, for example, a conductive oxide as its main component.

[0029] 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). An example of an antimony-containing conductive oxide is antimony-tin composite oxide (ATO). From the viewpoint of achieving high transparency and good electrical conductivity, indium-containing conductive oxides are preferably used as conductive oxides, and ITO is more preferably used. This ITO may contain metals or metalloids other than In and Sn in amounts less than the respective contents of In and Sn.

[0030] When ITO is used as the conductive oxide, the ratio of 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 (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. These configurations are suitable for ensuring the durability of the transparent conductive layer 20. Furthermore, the ratio of tin oxide content to the total content of indium oxide (In2O3) and tin oxide (SnO2) in the ITO 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 tin atoms to indium atoms in ITO (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 transparent conductive layer 20 that easily crystallizes upon heating. The ratio of tin atoms to indium atoms in ITO can be determined, for example, by identifying the relative abundance of indium atoms and tin atoms in the object to be measured using X-ray photoelectron spectroscopy. The above-mentioned content of tin oxide in ITO can be determined, for example, from the relative abundance of indium atoms and tin atoms identified in this way. The above-mentioned content of tin oxide in ITO may also be determined from the tin oxide (SnO2) content of the ITO target used during sputter deposition.

[0031] The transparent conductive layer 20 may contain noble gas atoms. Examples of noble gas atoms include argon (Ar), krypton (Kr), and xenon (Xe). In this embodiment, the noble gas atoms in the transparent conductive layer 20 are derived from the noble gas atoms used as sputtering gas in the sputtering method described later for forming the transparent conductive layer 20. In this embodiment, the transparent conductive layer 20 is a film formed by the sputtering method (sputtered film).

[0032] If the transparent conductive layer 20 contains a noble gas atom, the noble gas atom is preferably Kr. This configuration is suitable for achieving good crystal growth and forming large crystal grains when the amorphous transparent conductive layer 20 is crystallized by heating to form a crystalline transparent conductive layer 20', and therefore is suitable for obtaining a transparent conductive layer 20' with low resistance (the larger the crystal grains in the transparent conductive layer 20', the lower the resistance of the transparent conductive layer 20').

[0033] The content of noble gas atoms (including Kr) in the transparent conductive layer 20 is preferably 1 atomic% or less, more preferably 0.5 atomic% or less, even more preferably 0.3 atomic% or less, and particularly preferably 0.2 atomic% or less, throughout the entire thickness direction H. This configuration is suitable for achieving good crystal growth and forming large crystal grains when the amorphous transparent conductive layer 20 is crystallized by heating to form a crystalline transparent conductive layer 20', and therefore is suitable for obtaining a low-resistance transparent conductive layer 20'. The content of noble gas atoms in the transparent conductive layer 20 is preferably 0.0001 atomic% or more throughout the entire thickness direction H. The transparent conductive layer 20 may include a region in at least a part of the thickness direction H where the content of noble gas atoms is less than 0.0001 atomic% (i.e., in a part of the thickness direction H, the proportion of noble gas atoms in the cross-section in the plane direction perpendicular to the thickness direction H may be less than 0.0001 atomic%). The presence or absence of noble gas atoms in the transparent conductive layer 20 can be identified, for example, by X-ray fluorescence analysis.

[0034] If the transparent conductive layer 20 contains Kr, the Kr content in the transparent conductive layer 20 may be non-uniform in the thickness direction H. For example, in the thickness direction H, the Kr content may gradually increase or decrease as it moves away from the transparent resin substrate 10. Alternatively, in the thickness direction H, a region where the Kr content gradually increases as it moves away from the transparent resin substrate 10 may be located on the side of the transparent resin substrate 10, and a region where the Kr content gradually decreases as it moves away from the transparent resin substrate 10 may be located on the opposite side of the transparent resin substrate 10. Alternatively, in the thickness direction H, a region where the Kr content gradually decreases as it moves away from the transparent resin substrate 10 may be located on the side of the transparent resin substrate 10, and a region where the Kr content gradually increases as it moves away from the transparent resin substrate 10 may be located on the opposite side of the transparent resin substrate 10.

[0035] The transparent conductive layer 20 may contain Kr in a portion of the thickness direction H, as illustrated in Figure 2. Figure 2A shows the case where the transparent conductive layer 20 contains a first region 21 and a second region 22 in that order from the transparent resin substrate 10 side. The first region 21 contains Kr. The second region 22 does not contain Kr and contains, for example, a noble gas atom other than Kr. Ar is preferably the noble gas atom other than Kr. Figure 2B shows the case where the transparent conductive layer 20 contains a second region 22 and a first region 21 in that order from the transparent resin substrate 10 side. In Figure 2, the boundary between the first region 21 and the second region 22 is depicted by a dashed line. In cases where the composition of the first region 21 and the second region 22 is not significantly different in aspects other than the noble gas atom, which is present in trace amounts, the boundary between the first region 21 and the second region 22 may not be clearly distinguishable. From the viewpoint of reducing the resistance of the transparent conductive layer 20' obtained by crystallizing the transparent conductive layer 20, the transparent conductive layer 20 includes a first region 21 (Kr-containing region) and a second region 22 (Kr-free region) in this order from the transparent resin substrate 10 side.

[0036] When the transparent conductive layer 20 includes a first region 21 and a 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 10% or more, more preferably 20% or more, even more preferably 30% or more, and particularly preferably 40% 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 90% or less, more preferably 80% or less, even more preferably 70% or less, and particularly preferably 60% or less. When the transparent conductive layer 20 includes a first region 21 and a second region 22, these configurations regarding the respective thickness ratios of the first region 21 and the second region 22 are preferable from the viewpoint of reducing the resistance of the transparent conductive layer 20' obtained by crystallizing the transparent conductive layer 20.

[0037] The Kr content in the first region 21 is as follows: Preferably, the content is 1 atomic% or less, more preferably 0.5 atomic% or less, even more preferably 0.3 atomic% or less, and particularly preferably 0.2 atomic% or less. Such a configuration is preferable from the viewpoint of reducing the resistance of the transparent conductive layer 20' obtained by crystallizing the transparent 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 H of the first region 21.

[0038] Furthermore, the Kr content in the first region 21 may be non-uniform in the thickness direction H of the first region 21. For example, in the thickness direction H of the first region 21, the Kr content may gradually increase or decrease as you move away from the transparent resin substrate 10. Alternatively, in the thickness direction H of the first region 21, a portion of the region where the Kr content gradually increases as you move away from the transparent resin substrate 10 may be located on the side of the transparent resin substrate 10, and a portion of the region where the Kr content gradually decreases as you move away from the transparent resin substrate 10 may be located on the opposite side of the transparent resin substrate 10. Alternatively, in the thickness direction H of the first region 21, a portion of the region where the Kr content gradually decreases as you move away from the transparent resin substrate 10 may be located on the side of the transparent resin substrate 10, and a portion of the region where the Kr content gradually increases as you move away from the transparent resin substrate 10 may be located on the opposite side of the transparent resin substrate 10.

[0039] The thickness of the transparent conductive layer 20 is preferably 10 nm or more, more preferably 20 nm or more, still more preferably 25 nm or more. Such a configuration is preferable from the viewpoint of reducing the resistance of the transparent conductive layer 20'obtained by crystallizing the transparent conductive layer 20. Further, the thickness of the transparent conductive layer 20 is, for example, 1000 nm or less, preferably less than 300 nm, more preferably 250 nm or less, still more preferably 200 nm or less, even more preferably 160 nm or less, particularly preferably less than 150 nm, and most preferably less than 148 nm. Such a configuration is suitable for suppressing warpage in the transparent conductive film X including the transparent conductive layer 20'obtained by crystallizing the transparent conductive layer 20.

[0040] The specific resistance of the transparent conductive layer 20 is preferably 4×10 -4 Ω·cm or more, more preferably 4.5×10 -4 Ω·cm or more, still more preferably 5×10 -4 Ω·cm or more, even more preferably 5.5×10 -4 Ω·cm or more, particularly preferably 5.8×10 -4 Ω·cm or more. The specific resistance of the transparent conductive layer 20 is preferably 20×10 -4 Ω·cm or less, more preferably 15×10 -4 Ω·cm or less, still more preferably 10×10 -4 Ω·cm or less, particularly preferably 8×10 -4 Ω·cm or less. These configurations regarding the specific resistance are preferable from the viewpoint of reducing the resistance of the transparent conductive layer 20'obtained by crystallizing the transparent conductive layer 20. The specific resistance is obtained by multiplying the surface resistance by the thickness. Further, the specific resistance can be controlled, for example, by adjusting various conditions when forming the transparent conductive layer 20 by sputtering. Examples of such conditions include the temperature of the base (the transparent resin substrate 10 in the present embodiment) on which the transparent conductive layer 20 is formed, the amount of oxygen introduced into the film formation chamber, the atmospheric pressure in the film formation chamber, and the horizontal magnetic field strength on the target.

[0041] The specific resistance of the transparent conductive layer 20 after heat treatment at 165°C for 60 minutes is preferably 3×10 -4Ω·cm or less, more preferably 2.8 × 10 -4 Ω·cm or less, more preferably 2.5 × 10 -4 Ω·cm or less, more preferably 2.2 × 10 -4 Ω·cm or less, particularly preferably 2.0 × 10⁻⁶ -4 The resistivity is less than or equal to Ω·cm. Furthermore, the resistivity of the transparent conductive layer 20 after heat treatment at 165°C for 60 minutes is preferably 0.1 × 10⁻⁶. -4 Ω·cm or more, more preferably 0.5 × 10 -4 Ω·cm or greater, more preferably 1.0 × 10⁻⁶ -4 The resistance is Ω·cm or greater. These configurations are suitable for ensuring the low resistance required for transparent conductive layers in touch sensors, dimming elements, photoelectric conversion elements, heat control members, antenna members, electromagnetic wave shielding members, heater members, lighting devices, and image display devices.

[0042] The total light transmittance of the transparent conductive layer 20 (JIS K 7375-2008) 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 for the transparent conductive film X when it is provided in touch sensors, dimming elements, photoelectric conversion elements, heat control members, antenna members, electromagnetic wave shielding members, heater members, lighting devices, and image display devices. In addition, the total light transmittance of the transparent conductive layer 20 is, for example, 100% or less.

[0043] The amorphous nature of a transparent conductive layer can be determined, for example, as follows: First, the transparent conductive layer (in the case of transparent conductive film X, the transparent conductive layer 20 on the transparent resin substrate 10) is immersed in 5% by mass hydrochloric acid at 20°C for 15 minutes. Next, the transparent conductive layer is washed with water and dried. Then, the resistance between a pair of terminals separated by 15 mm is measured on the exposed surface of the transparent conductive layer (in the case of transparent conductive film X, the surface of the transparent conductive layer 20 opposite to the transparent resin substrate 10). If the resistance between terminals exceeds 10 kΩ in this measurement, the transparent conductive layer is amorphous.

[0044] The direction in which the transparent conductive film X shrinks most when subjected to heat treatment under heating conditions of 165°C for 60 minutes is defined as the first direction. The thermal shrinkage rate of the transparent conductive film X in the first direction is preferably 1% or less, more preferably 0.8% or less, even more preferably 0.7% or less, and particularly preferably 0.6% or less, from the viewpoint of suppressing warping of the transparent conductive film X and suppressing the occurrence of cracks in the transparent conductive layer 20. This thermal shrinkage rate is, for example, 0% or more. The direction perpendicular to the first direction and the thickness direction H, respectively, when the transparent conductive film X undergoes the above heat treatment is defined as the second direction. The thermal shrinkage rate of the transparent conductive film X in the second direction (first thermal shrinkage rate T1) is preferably 1% or less, more preferably 0.8% or less, even more preferably 0.7% or less, and particularly preferably 0.6% or less, from the viewpoint of suppressing warping of the transparent conductive film X and suppressing the occurrence of cracks in the transparent conductive layer 20. The thermal shrinkage rate is, for example, 0% or more, and preferably 0.0% or more.

[0045] The thermal shrinkage rate of the transparent conductive film X can be determined by measuring the dimensional change of the transparent conductive film X after sequentially undergoing heat treatment and standing at room temperature for, for example, 30 minutes (the thermal shrinkage rate of the transparent resin substrate 10 can be determined similarly). Furthermore, the first direction in which the thermal shrinkage rate of the transparent conductive film X is maximum can be determined, for example, by measuring the dimensional change rate before and after heat treatment in the axial direction at 15° increments from a reference axis (0°) extending in any direction in the transparent conductive film X. The first direction is, for example, the MD direction for the transparent conductive film X (i.e., the film running direction in the manufacturing process described later using the roll-to-roll method). If the first direction is the MD direction, the second direction is the TD direction, which is perpendicular to both the MD direction and the thickness direction H.

[0046] When the transparent resin substrate 10 undergoes heat treatment under heating conditions of 165°C for 60 minutes, the thermal shrinkage rate of the transparent resin substrate 10 in the first direction is preferably 1% or less, more preferably 0.8% or less, even more preferably 0.7% or less, and particularly preferably 0.6% or less, from the viewpoint of suppressing warping of the transparent resin substrate 10 and suppressing the occurrence of cracks in the transparent conductive layer 20. Furthermore, when the transparent resin substrate 10 undergoes the heat treatment, the thermal shrinkage rate of the transparent resin substrate 10 in the second direction (second thermal shrinkage rate T2) is preferably 1% or less, more preferably 0.8% or less, even more preferably 0.7% or less, and particularly preferably 0.6% or less, from the viewpoint of suppressing warping of the transparent conductive film X and suppressing the occurrence of cracks in the transparent conductive layer 20. The thermal shrinkage rate is, for example, 0% or more, and preferably 0.0% or more.

[0047] The first thermal shrinkage rate T1 of the transparent conductive film X and the second thermal shrinkage rate T2 of the transparent resin substrate 10 satisfy |T1-T2| < 0.12%, and more preferably |T1-T2| ≤ 0.11%. Such a configuration is suitable for suppressing the generation of excessive internal stress when the transparent conductive layer 20 undergoes a heating process.

[0048] The transparent conductive film X is manufactured, for example, as follows:

[0049] First, prepare the resin film 11 as shown in Figure 3A.

[0050] Next, as shown in Figure 3B, a functional layer 12 is formed on one surface of the resin film 11 in the thickness direction H. By forming the functional layer 12 on the resin film 11, a transparent resin substrate 10 is produced.

[0051] The functional layer 12 described above, which serves as a hard coat layer, can be formed by applying a curable resin composition to the resin film 11 to form a coating film, and then curing this coating film. If the curable resin composition contains an ultraviolet-curable resin, the coating film is cured by ultraviolet irradiation. If the curable resin composition contains a thermosetting resin, the coating film is cured by heating.

[0052] The exposed surface of the functional layer 12 formed on the resin film 11 is subjected to surface modification treatment as needed. When plasma treatment is used as the surface modification treatment, argon gas, for example, is used as the inert gas. The discharge power in the plasma treatment is, for example, 10W or more, and for example, 5000W or less.

[0053] Next, as shown in Figure 3C, a transparent conductive layer 20 is formed on the transparent resin substrate 10. Specifically, the transparent conductive layer 20 is formed by depositing a material onto the functional layer 12 of the transparent resin substrate 10 using a sputtering method.

[0054] In the sputtering method, it is preferable to use a sputtering deposition apparatus that can perform the film deposition process in a roll-to-roll manner. When using a roll-to-roll sputtering deposition apparatus in the manufacture of the transparent conductive film X, a long transparent resin substrate 10 is moved from the feed roll to the winding roll of the apparatus, and a material is deposited on the transparent resin substrate 10 to form a transparent conductive layer 20. In this sputtering method, a sputtering deposition apparatus with one deposition chamber may be used, or a sputtering deposition apparatus with multiple deposition chambers arranged sequentially along the travel path of the transparent resin substrate 10 may be used (when forming a transparent conductive layer 20 including the first region 21 and the second region 22 described above, a sputtering deposition apparatus with multiple deposition chambers is used).

[0055] In the sputtering method, specifically, a sputtering gas (inert gas) is introduced into the deposition chamber of a sputtering deposition apparatus under vacuum conditions, while a negative voltage is applied to a target placed on the cathode in the deposition chamber. This generates a glow discharge, ionizing the gas atoms, which then collide with the target surface at high speed, ejecting the target material from the target surface. This ejected target material is then deposited onto the functional layer 12 of the transparent resin substrate 10.

[0056] As the target material placed on the cathode in the film deposition chamber, the conductive oxide described above for forming the transparent conductive layer 20 is used, preferably ITO. The ratio of the tin oxide content to the total content of tin oxide and indium oxide in the ITO is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, even more preferably 5% by mass or more, particularly preferably 7% by mass or more, and also preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 12% by mass or less.

[0057] The sputtering method is preferably a reactive sputtering method. In the reactive sputtering method, a reactive gas is introduced into the deposition chamber in addition to the sputtering gas.

[0058] In the first case, when forming a transparent conductive layer 20 containing Kr over the entire thickness direction H, 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 also contain inert gases other than Kr. Examples of inert gases other than Kr include noble gas atoms other than Kr. Examples of noble gas atoms include Ar and Xe. When the sputtering gas contains inert gases other than Kr, the content is preferably 80% by volume or less, more preferably 50% by volume or less.

[0059] In the case of forming a transparent conductive layer 20 including the first region 21 and the second region 22 described above (the 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 also contain an inert gas other than Kr. The type and content ratio 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.

[0060] Furthermore, in the second case described above, 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. The inert gas other than Kr is the inert gas mentioned above as the inert gas other than Kr in the first case.

[0061] 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 deposition chamber is, for example, 0.01% or more, and for example, 15% or less.

[0062] The atmospheric pressure inside the deposition chamber during film deposition by sputtering (sputter deposition) is, for example, 0.02 Pa or higher, and also, for example, 1 Pa or lower.

[0063] The temperature of the transparent resin substrate 10 during sputtering is, for example, 100°C or less, preferably 50°C or less, more preferably 30°C or less, even more preferably 10°C or less, and particularly preferably 0°C or less. It is also, 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.

[0064] Examples of power supplies for applying voltage to the target include DC power supplies, AC power supplies, MF power supplies, and RF power supplies. A DC power supply and an RF power supply may be used in combination. The absolute value of the discharge voltage during sputter deposition is, for example, 50V or more, and also, for example, 500V or less, preferably 400V or less.

[0065] For example, a transparent conductive film X can be manufactured in the manner described above.

[0066] The transparent conductive layer 20 in the transparent conductive film X may be patterned, as schematically shown in Figure 4. The transparent conductive layer 20 can be patterned by etching it through a predetermined etching mask. The patterned transparent conductive layer 20 can function, for example, as a wiring pattern.

[0067] Furthermore, the transparent conductive layer 20 in the transparent conductive film X is converted into a crystalline transparent conductive layer 20' (shown in Figure 5) by heating. Examples of heating methods include infrared heaters and ovens (heat transfer medium heating ovens, hot air heating ovens). The heating environment may be either a vacuum environment or an atmospheric environment. Preferably, heating is carried out in the presence of oxygen. From the viewpoint of ensuring a high crystallization rate, the heating temperature is, for example, 100°C or higher, preferably 120°C or higher. From the viewpoint of suppressing the effect of heating on the transparent resin 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, less than 600 minutes, preferably less than 120 minutes, more preferably 90 minutes or lower, and even more preferably 60 minutes or lower, and also, for example, 1 minute or more, preferably 5 minutes or more. The patterning of the transparent conductive layer 20 described above may be carried out before or after heating for crystallization.

[0068] The resistivity of the transparent conductive layer 20' is preferably 3 × 10 -4 Ω·cm or less, more preferably 2.8 × 10 -4 Ω·cm or less, more preferably 2.5 × 10 -4 Ω·cm or less, more preferably 2.2 × 10 -4 Ω·cm or less, particularly preferably 2.0 × 10⁻⁶ -4 It is less than or equal to Ω·cm. Furthermore, the resistivity of the transparent conductive layer 20' is preferably 0.1 × 10⁻⁶. -4 Ω·cm or more, more preferably 0.5 × 10 -4Ω·cm or greater, more preferably 1.0 × 10⁻⁶ -4 It is greater than Ω·cm.

[0069] The total light transmittance of the transparent conductive layer 20' (JIS K 7375-2008) is preferably 65% ​​or more, more preferably 80% or more, and even more preferably 85% or more. The total light transmittance of the transparent conductive layer 20 is, for example, 100% or less.

[0070] In the transparent conductive film X, as described above, the transparent conductive layer 20 is amorphous, and the first thermal shrinkage rate T1 of the transparent conductive film X and the second thermal shrinkage rate T2 of the transparent resin substrate 10 satisfy |T1-T2|<0.12%. Therefore, the transparent conductive film X is suitable for suppressing the generation of excessive internal stress (e.g., compressive stress or tensile stress in the in-plane direction) in the crystalline transparent conductive layer 20' formed by heating the amorphous transparent conductive layer 20. Such a transparent conductive film X is suitable for obtaining a transparent conductive film having a crystalline transparent conductive layer in which crack formation is suppressed.

[0071] In the transparent conductive film X, the functional layer 12 may be an adhesion-enhancing layer to achieve high adhesion between the transparent conductive layer 20 (or the transparent conductive layer 20' after crystallization of the transparent conductive layer 20; the same applies hereinafter) and the transparent resin substrate 10. A configuration in which the functional layer 12 is an adhesion-enhancing layer is suitable for ensuring adhesion between the transparent resin substrate 10 and the transparent conductive layer 20.

[0072] The functional layer 12 may be an index-matching layer for adjusting the reflectivity of the surface (one side in the thickness direction H) of the transparent resin substrate 10. A configuration in which the functional layer 12 is an index-matching layer is suitable for making the pattern shape of the transparent conductive layer 20 on the transparent resin substrate 10 less visible when the transparent conductive layer 20 on the transparent resin substrate 10 is patterned.

[0073] The functional layer 12 may be a release functional layer that makes it practically possible to peel the transparent conductive layer 20 from the transparent resin substrate 10. A configuration in which the functional layer 12 is a release functional layer is suitable for peeling the transparent conductive layer 20 from the transparent resin substrate 10 and transferring the transparent conductive layer 20 to another component.

[0074] The functional layer 12 may be a composite layer in which multiple layers are connected in the thickness direction H. Preferably, the composite layer includes two or more layers selected from the group consisting of a hard coat layer, an adhesion-enhancing layer, a refractive index-adjusting layer, and a release-functional layer. Such a configuration is suitable for the functional layer 12 to comprehensively exhibit the above-mentioned functions of each selected layer. In one preferred embodiment, the functional layer 12 comprises an adhesion-enhancing layer, a hard coat layer, and a refractive index-adjusting layer on the resin film 11 in this order toward one side in the thickness direction H. In another preferred embodiment, the functional layer 12 comprises a release-functional layer, a hard coat layer, and a refractive index-adjusting layer on the resin film 11 in this order toward one side in the thickness direction H. Furthermore, the functional layer 12 may not be provided in the transparent conductive film X. That is, the transparent conductive film X may comprise the above-mentioned resin film 11 as the transparent resin substrate 10.

[0075] The transparent conductive film X is used in a state where it is fixed to an article and, if necessary, the transparent conductive layer 20' is patterned. The transparent conductive film X is bonded to the article, for example, via a bonding functional layer.

[0076] Examples of articles include elements, components, and devices. Specifically, examples of articles with a transparent conductive film include elements with a transparent conductive film, components with a transparent conductive film, and devices with a transparent conductive film.

[0077] 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 control members, heater members, and antenna members. Examples of devices include touch sensor devices, lighting devices, and image display devices.

[0078] Examples of the above-mentioned adhesive functional layer include an adhesive layer and a bonding layer. The material of the adhesive functional layer is not particularly limited as long as it is transparent and exhibits adhesive properties. Preferably, the adhesive functional layer is 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 cohesiveness, adhesion, and appropriate wettability, has excellent transparency, and has excellent weather resistance and heat resistance.

[0079] The adhesive layer (the resin forming the adhesive layer) may contain a corrosion inhibitor to suppress corrosion of the transparent conductive layer 20'. The adhesive layer (the resin forming the adhesive layer) may also contain a migration inhibitor (for example, the material disclosed in Japanese Patent Application Publication No. 2015-022397) to suppress migration of the transparent conductive layer 20'. Furthermore, the adhesive layer (the resin forming the adhesive layer) may contain an ultraviolet absorber to suppress deterioration of the article when used outdoors. Examples of ultraviolet absorbers include benzophenone compounds, benzotriazole compounds, salicylic acid compounds, oxalic acid anilide compounds, cyanoacrylate compounds, and triazine compounds.

[0080] Furthermore, when the transparent substrate 10 of the transparent conductive film X is fixed to an article via a bonding functional layer, the transparent conductive layer 20' (including the transparent conductive layer 20' after patterning) is exposed in the transparent conductive film X. In such cases, a cover layer may be placed on the exposed surface of the transparent conductive layer 20'. The cover layer is a layer that covers the transparent conductive layer 20', improving the reliability of the transparent conductive layer 20' and suppressing functional deterioration due to damage to the transparent conductive layer 20'. Such a cover layer is preferably formed from a dielectric material, and more preferably from a composite material of a resin and an inorganic material. Examples of resins include the resins described above with respect to the bonding 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. Furthermore, the cover layer (a mixture of resin and inorganic materials) may contain the above-mentioned corrosion inhibitors, migration inhibitors, and ultraviolet absorbers. [Examples]

[0081] The present invention will be specifically described below with reference to examples. The present invention is not limited to these examples. Furthermore, the specific numerical values ​​such as the amounts (contents), physical properties, and parameters described below can be substituted with the upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or "greater than") of the corresponding amounts (contents), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0082] [Example 1] A long stretch of polyethylene terephthalate (PET) film (50 μm thick, manufactured by Toray Industries, Inc.), used as a transparent resin film, was coated with an ultraviolet-curable resin containing acrylic resin on one side to form a coating. Next, the coating was cured by ultraviolet irradiation to form a hard coat layer (2 μm thick). In this way, a transparent resin substrate comprising a resin film and a hard coat layer as a functional layer was produced.

[0083] Next, a 130 nm thick amorphous transparent conductive layer was formed on the hard coat layer of a transparent resin substrate using a reactive sputtering method. For the reactive sputtering method, a sputtering apparatus (DC magnetron sputtering apparatus) capable of performing the film deposition process in a roll-to-roll manner was used. The sputtering deposition conditions in this embodiment were as follows:

[0084] 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 to apply voltage to the target (horizontal magnetic field strength on the target was 90 mT). The deposition temperature (temperature of the transparent resin substrate on which the transparent conductive layer is laminated) was set to -5°C. The achievable vacuum in the deposition chamber of the apparatus was 0.9 × 10⁻⁶. -4After evacuating the deposition chamber to a pressure of Pa, Kr as the sputtering gas and oxygen as the reactive gas were introduced into the deposition chamber, and the atmospheric pressure inside the deposition 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 deposition chamber was approximately 2.6 flow rate%, and as shown in Figure 6, this amount of oxygen introduced was within the region R of the resistivity-oxygen introduction curve, and the resistivity of the formed ITO film was 6.7 × 10⁻⁶. -4 The resistance was adjusted to Ω·cm. The resistivity-oxygen introduction curve shown in Figure 6 can be created by first investigating the dependence of the resistivity of the transparent conductive layer on the oxygen introduction amount when the transparent conductive layer is formed by reactive sputtering under the same conditions as above, except for the oxygen introduction amount.

[0085] The transparent conductive film of Example 1 was prepared as described above. The transparent conductive layer (thickness 130 nm, amorphous) of the transparent conductive film of Example 1 consists of a single Kr-containing ITO layer.

[0086] [Example 2] The transparent conductive film of Example 2 was prepared in the same manner as the transparent conductive film of Example 1, except as follows: In sputter deposition, the atmospheric pressure in the deposition chamber was set to 0.2 Pa, and the amount of oxygen introduced into the deposition chamber was set to the resistivity of the formed ITO film, which was 6.0 × 10⁻⁶. -4 A 25 nm thick amorphous transparent conductive layer was formed while adjusting it to achieve a density of Ω·cm.

[0087] The transparent conductive layer (25 nm thick, amorphous) of the transparent conductive film in Example 2 consists of a single Kr-containing ITO layer.

[0088] [Example 3] The transparent conductive film of Example 3 was fabricated in the same manner as the transparent conductive film of Example 1, except that a first sputter deposition was performed to form a first region (thickness 26 nm) of the transparent conductive layer on a transparent resin substrate, followed by a second sputter deposition to form a second region (thickness 104 nm) of the transparent conductive layer on the first region.

[0089] The conditions for the first sputtering deposition in this embodiment are as follows: A sintered body of indium oxide and tin oxide (tin oxide concentration of 10 mass%) was used as the target. A DC power supply was used to apply voltage to the target (horizontal magnetic field strength on the target was 90 mT). The deposition temperature was -5°C. The ultimate vacuum level in the first deposition chamber of the apparatus was set to 0.9 × 10⁻⁶. -4 After setting the pressure to Pa, Kr as a sputtering gas and oxygen as a reactive gas were introduced into the deposition chamber, and the atmospheric pressure inside the deposition chamber was set to 0.2 Pa. The amount of oxygen introduced into the deposition chamber was such that the resistivity of the formed ITO film was 6.5 × 10⁻⁶. -4 It was adjusted to be Ω·cm.

[0090] The conditions for the second sputter deposition in this embodiment are as follows: The ultimate vacuum level in the second deposition chamber of the apparatus is set to 0.9 × 10⁻⁶ -4 After setting the pressure to Pa, Ar as the sputtering gas and oxygen as the reactive gas were introduced into the deposition chamber, and the atmospheric pressure inside the deposition chamber was set to 0.4 Pa. In this embodiment, the other conditions for the second sputter deposition were the same as those for the first sputter deposition.

[0091] The transparent conductive film of Example 3 was prepared as described above. The transparent conductive layer (thickness 130 nm, amorphous) of the transparent conductive film of Example 3 has, in order from the transparent resin substrate side, a first region (thickness 26 nm) consisting of a Kr-containing ITO layer and a second region (thickness 104 nm) consisting of an Ar-containing ITO layer (the ratio of the thickness of the first region to the thickness of the transparent conductive layer is 20%, and the ratio of the thickness of the second region to the thickness is 80%).

[0092] [Example 4] The transparent conductive film of Example 4 was prepared in the same manner as the transparent conductive film of Example 3, except as follows: In the first sputter deposition, the amount of oxygen introduced into the deposition chamber was set to the resistivity of the formed ITO film, which was 6.2 × 10⁻⁶. -4 A first region with a thickness of 52 nm was formed while adjusting the resistance to Ω·cm. In the second sputter deposition, the amount of oxygen introduced into the deposition chamber was adjusted so that the resistivity of the formed ITO film was 6.2 × 10⁻⁶. -4A second region with a thickness of 78 nm was formed while adjusting it to be Ω·cm.

[0093] The transparent conductive layer (130 nm thick, amorphous) of the transparent conductive film of Example 4 has, in order from the transparent resin substrate side, a first region (52 nm thick) consisting of a Kr-containing ITO layer and a second region (78 nm thick) consisting of an Ar-containing ITO layer (the ratio of the thickness of the first region to the thickness of the transparent conductive layer is 40%, and the ratio of the thickness of the second region to the thickness is 60%).

[0094] [Example 5] The transparent conductive film of Example 5 was fabricated in the same manner as the transparent conductive film of Example 3, except for the following: In the first sputter deposition, a first region with a thickness of 63 nm was formed. In the second sputter deposition, a second region with a thickness of 27 nm was formed.

[0095] The transparent conductive layer (90 nm thick, amorphous) of the transparent conductive film of Example 5 has, in order from the transparent resin substrate side, a first region (63 nm thick) consisting of a Kr-containing ITO layer and a second region (27 nm thick) consisting of an Ar-containing ITO layer (the ratio of the thickness of the first region to the thickness of the transparent conductive layer is 70%, and the ratio of the thickness of the second region to the thickness is 30%).

[0096] [Example 6] The transparent conductive film of Example 6 was prepared in the same manner as the transparent conductive film of Example 1, except for the following in the sputtering deposition process: A mixed gas of krypton and argon (Kr 85 vol%, Ar 15 vol%) was used as the sputtering gas. The amount of oxygen introduced into the deposition chamber was determined to match the resistivity of the formed film, which was 5.9 × 10⁻⁶. -4 The impedance was adjusted to Ω·cm. The thickness of the formed transparent conductive layer was set to 145 nm.

[0097] The transparent conductive layer (145 nm thick, amorphous) of the transparent conductive film in Example 6 consists of a single ITO layer containing Kr and Ar.

[0098] [Example 7] The transparent conductive film of Example 7 was prepared in the same manner as the transparent conductive film of Example 1, except as follows: A long polyethylene terephthalate (PET) film (125 μm thick, manufactured by Mitsubishi Chemical Corporation) was used as the transparent resin substrate.

[0099] In the transparent conductive film of Example 7, the transparent resin substrate is made of a PET film (thickness 125 μm), and the transparent conductive layer (thickness 130 nm, amorphous) is made of a single Kr-containing ITO layer.

[0100] [Example 8] The transparent conductive film of Example 8 was prepared in the same manner as the transparent conductive film of Example 1, except as follows: In sputter deposition, Ar was used as the sputtering gas, the atmospheric pressure in the deposition chamber was set to 0.4 Pa, and the amount of oxygen introduced into the deposition chamber was set to the resistivity of the formed ITO film, which was 6.2 × 10⁻⁶. -4 It was adjusted to be Ω·cm.

[0101] The transparent conductive layer (130 nm thick, amorphous) of the transparent conductive film in Example 8 consists of a single Ar-containing ITO layer.

[0102] [Comparative Example 1] A transparent conductive film of Comparative Example 1 was prepared in the same manner as the transparent conductive film of Example 1, except as follows: In sputter deposition, the amount of oxygen introduced into the deposition chamber was set to the resistivity of the formed ITO film, which was 5.7 × 10⁻⁶. -4 It was adjusted to be Ω·cm.

[0103] The transparent conductive layer (130 nm thick, amorphous) of the transparent conductive film in Comparative Example 1 consists of a single Kr-containing ITO layer.

[0104] [Comparative Example 2] The transparent conductive film of Comparative Example 2 was prepared in the same manner as the transparent conductive film of Example 3, except for the following: In the first sputter deposition, a first region with a thickness of 98 nm was formed. In the second sputter deposition, a second region with a thickness of 32 nm was formed.

[0105] The transparent conductive layer (130 nm thick, amorphous) of the transparent conductive film of Comparative Example 2 has a first region (98 nm thick) consisting of a Kr-containing ITO layer and a second region (32 nm thick) consisting of an Ar-containing ITO layer, in that order from the transparent resin substrate side (the ratio of the thickness of the first region to the thickness of the transparent conductive layer is 75%, and the ratio of the thickness of the second region to the thickness of the transparent conductive layer is 25%).

[0106] <Thickness of the transparent conductive layer> The thickness of each transparent conductive layer in Examples 1-8 and Comparative Examples 1 and 2 was measured by FE-TEM observation. Specifically, first, samples for cross-sectional observation of each transparent conductive layer in Examples 1-8 and Comparative Examples 1 and 2 were prepared by the FIB microsampling method. For the FIB microsampling method, a FIB device (product name "FB2200", manufactured by Hitachi) was used, and the acceleration voltage was set to 10kV. Next, the thickness of the transparent conductive layer in the cross-sectional observation samples was measured by FE-TEM observation. For the FE-TEM observation, a FE-TEM device (product name "JEM-2800", manufactured by JEOL) was used, and the acceleration voltage was set to 200kV.

[0107] The thickness of the first region of each transparent conductive layer in Examples 3-5 and Comparative Example 2 was measured by FE-TEM observation of a sample prepared from an intermediate fabrication before the formation of the second region on the first region. The thickness of the second region of each transparent conductive layer in Examples 3-5 and Comparative Example 2 was determined by subtracting the thickness of the first region from the total thickness of the transparent conductive layer.

[0108] <Specific resistance> The resistivity of each transparent conductive layer in Examples 1-8 and Comparative Examples 1 and 2 after heat treatment was investigated. For the heat treatment, a hot air oven was used as the heating method, with a heating temperature of 165°C and a heating time of 60 minutes. The surface resistance of the transparent conductive layer was measured using the four-terminal method in accordance with JIS K 7194 (1994), and then the resistivity (Ω·cm) was determined by multiplying the surface resistance value by the thickness of the transparent conductive layer. The resistivity values ​​(R1) after heat treatment are shown in Table 1. Table 1 also shows the resistivity values ​​(R2) before heat treatment. Furthermore, regarding the low resistance of each transparent conductive layer in Examples 1-8 and Comparative Examples 1 and 2, the resistivity after the above heat treatment was 2.2 × 10⁻⁶. -4 A value of Ω·cm or less is evaluated as "good," and the resistivity after the above heat treatment is 2.2 × 10⁻⁶. -4 A value exceeding Ω·cm was evaluated as "defective." The results of this evaluation are also shown in Table 1.

[0109] <Confirmation of Kr atoms in the transparent conductive layer> The presence of Kr atoms in each transparent conductive layer in Examples 1-7 and Comparative Examples 1 and 2 was confirmed as follows. First, using a scanning X-ray fluorescence analyzer (product 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 the transparent conductive layer contained Kr atoms. On the other hand, no peak was observed near a scanning angle of 28.2° for the transparent conductive layer of Example 8 (i.e., it was not confirmed that it contained Kr).

[0110] <Measurement conditions> Spectrum; Kr-KA Measurement diameter: 30mm 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

[0111] <Quantitative determination of Kr atoms in a transparent conductive layer> The Kr content of each transparent conductive layer in Examples 1-7 and Comparative Examples 1 and 2 was analyzed by Rutherford Back Scattering Spectrometry (RBS). The Kr atom content (atomic %) in the transparent conductive layer was determined by calculating the elemental ratios of the four elements detected: In + Sn (since it is difficult to measure In and Sn separately in RBS, they were evaluated as a sum of the two elements), O, and Kr. The equipment and measurement conditions used are as follows. Regarding the analysis of Kr content, reliable measurements above the detection limit (lower limit) could not be obtained in Examples 1-7 and Comparative Examples 1 and 2 (the detection limit may vary depending on the thickness of the transparent conductive layer being measured). Specifically, the Kr content of each transparent conductive layer in Examples 1, 3-7 and Comparative Examples 1 and 2 was less than 0.2 atomic % (detection limit), and the Kr content of the transparent conductive layer in Example 2 was less than 0.1 atomic % (detection limit).

[0112] <Equipment used> Pelletron 3SDH (manufactured by National Electrostatics Corporation)

[0113] <Measurement conditions> Incident ion: 4He++ Incident energy: 2300 keV Incident angle: 0 deg Scattering angle: 160deg Sample current: 6nA Beam diameter: 2mmφ In-plane rotation: None Irradiation dose: 75μC

[0114] <Thermal contraction rate> The thermal shrinkage rate after heat treatment was investigated for each transparent conductive film in Examples 1-8 and Comparative Examples 1 and 2. Specifically, three first sample films with dimensions of 10 cm on the first side and 10 cm on the second side were prepared for each transparent conductive film. The first side is the side extending in the MD direction for the transparent conductive film (i.e., the film running direction in the aforementioned manufacturing process using the roll-to-roll method) (the same applies to the first sample film described later). The second side is the side extending in the TD direction for the transparent conductive film (i.e., the direction perpendicular to the film running direction) (the same applies to the first sample film described later). Next, the shape of each first sample film was measured using a non-contact CNC image measuring machine (product name "QV ACCEL606-PRO", manufactured by Mitutoyo Corporation) (first measurement). Next, the first sample films were heat-treated in a hot air oven. In the heat treatment, the heating temperature was set to 165°C and the heating time to 60 minutes. Next, the shape of each first sample film, after being cooled to room temperature following the heat treatment, was measured using the non-contact CNC image measuring machine described above (second measurement). Based on the shape data obtained from the first measurement and the shape data obtained from the second measurement, it was determined that the direction in which the heat shrinkage rate due to the heat treatment was maximum (first direction) for each first sample film was the MD direction. Furthermore, the average of the heat shrinkage rates due to the heat treatment of a total of six second sides in the three first sample films for each transparent conductive film was calculated as the first heat shrinkage rate T1 (%) in the second direction. These values ​​are shown in Table 1.

[0115] The thermal shrinkage rate of the transparent resin substrate of each transparent conductive film in Examples 1-8 and Comparative Examples 1 and 2 after heat treatment was investigated. Specifically, first, three first sample films with dimensions of 10 cm on the first side and 10 cm on the second side were prepared for each transparent conductive film. Next, the first sample films were immersed in 5% by mass hydrochloric acid at 20°C for 30 minutes. This removed the transparent conductive layer from the first sample films, obtaining second sample films made of the transparent resin substrate. Subsequently, the first measurement, heat treatment, and second measurement described above were performed on the second sample films in the same manner as performed on the first sample films in the process of deriving the first thermal shrinkage rate T1. Based on the shape data obtained from the first measurement and the shape data obtained from the second measurement, it was determined that the direction in which the thermal shrinkage rate due to the heat treatment was maximum (first direction) was the MD direction for all second sample films. Furthermore, the average value of the heat shrinkage rate due to heat treatment of a total of six second edges in three second sample films for each transparent conductive film was determined as the second heat shrinkage rate T2 (%) in the second direction. This value is shown in Table 1. The absolute value of the difference between the first heat shrinkage rate T1 and the second heat shrinkage rate T2 (|T1-T2|) is also shown in Table 1.

[0116] <Evaluation of crack suppression> For each transparent conductive film in Examples 1-8 and Comparative Examples 1 and 2, the degree to which cracks occurred in the transparent conductive layer after heat treatment was investigated. Specifically, three transparent conductive films measuring 50 cm long x 5 cm short were prepared, and both short sides of each film were fixed to the surface of an iron plate with heat-resistant tape. Next, each transparent conductive film on the iron plate was heat-treated in a hot air oven. The heating temperature was set to 165°C and the heating time to 60 minutes. After the heat treatment, the transparent conductive films were cooled to room temperature and then subdivided into 5 cm x 5 cm pieces to obtain 30 observation samples. Next, each sample was observed using an optical microscope to check for the presence or absence of cracks. Regarding the suppression of crack occurrence in the transparent conductive layer of the transparent conductive film, a sample with 15 or fewer cracks in the transparent conductive layer was evaluated as "good," and a sample with 16 or more cracks was evaluated as "poor." The evaluation results are shown in Table 1.

[0117] [Table 1]

[0118] The embodiments described above are illustrative of the present invention and should not be interpreted as limiting the invention. Modifications of the present invention that are obvious to those skilled in the art are included in the claims below. [Industrial applicability]

[0119] The transparent conductive film of the present invention can be used, for example, as a supply material for conductive films to pattern transparent electrodes in various devices such as liquid crystal displays, touch panels, and optical sensors. [Explanation of symbols]

[0120] X Transparent conductive film H thickness direction 10 Transparent resin base material 11 Resin film 12 Functional Layers 20 Transparent conductive layer

Claims

1. A transparent conductive film comprising a transparent resin substrate and a transparent conductive layer in this order in the thickness direction, In the in-plane direction perpendicular to the thickness direction, there is a first direction in which the thermal shrinkage rate is maximized by heat treatment under heating conditions of 165°C for 60 minutes, and a second direction perpendicular to the first direction. The first thermal shrinkage rate T1 in the second direction of the transparent conductive film due to heat treatment under the heating conditions, and the second thermal shrinkage rate T2 in the second direction of the transparent resin substrate due to heat treatment under the heating conditions satisfy |T1-T2| < 0.12%. The first direction is the MD direction of the transparent conductive film, The second direction is the TD direction of the transparent conductive film, The transparent conductive layer is amorphous, A transparent conductive film wherein the resistivity of the transparent conductive layer is 5.8 × 10⁻⁴ Ω·cm or more and 15 × 10⁻⁴ Ω·cm or less.

2. The transparent conductive film according to claim 1, wherein the transparent conductive layer contains krypton.

3. A step of preparing the transparent conductive film described in claim 1, A method for producing a transparent conductive film, comprising the step of heating the transparent conductive layer to crystallize it.

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