Light-transmitting conductive layer and light-transmitting conductive sheet

Abstract

To provide an optically transparent conductive layer that offers low resistivity while exhibiting superior bendability, and an optically transparent conductive sheet including the optically transparent conductive layer.SOLUTION: An optically transparent conductive layer 3 includes a first principal face 11 and a second principal face 12 that face each other in the thickness direction. A first region 21 including the first principal face 11 and a second region 22 including the second principal face 12 are sequentially provided toward one side in the thickness direction. The main domain of the first region 21 is amorphous and the main domain of the second region 22 is crystalline. The first region 21 has a heterogeneous thickness.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light-transmitting conductive layer and a light-transmitting conductive sheet. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a light-transmitting conductive sheet is known which includes a substrate and a light-transmitting conductive layer in that order. Such a light-transmitting conductive sheet is suitably used in various devices (for example, a touch sensor).

[0003] As such a light-transmitting conductive sheet, for example, a light-transmitting conductive sheet has been proposed which includes a resin layer and a light-transmitting conductive layer, in that order, toward one side in the thickness direction, and the light-transmitting conductive layer includes a first region which is amorphous and a second region which is crystalline, in that order, toward one side in the thickness direction (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 241118 Brochure Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, the light-transmitting conductive layer is required to have a lower resistivity. In order to reduce the resistivity, it has been considered to increase the thickness of the light-transmitting conductive layer, but when the thickness of the light-transmitting conductive layer is increased, there is a problem that the flexibility is reduced.

[0006] The present invention provides a light-transmitting conductive layer that has low resistivity and excellent flexibility, and a light-transmitting conductive sheet that includes the light-transmitting conductive layer. [Means for solving the problem]

[0007] The present invention [1] provides a light-transmitting conductive layer having a first main surface and a second main surface opposing each other in the thickness direction, the light-transmitting conductive layer having a first region including the first main surface and a second region including the second main surface, in that order toward one side in the thickness direction, a main region of the first region is amorphous, a main region of the second region is crystalline, and the first region has a non-uniform thickness.

[0008] The present invention [2] includes the light-transmitting conductive layer according to the above [1], in which the second region is thicker than the first region.

[0009] The present invention [3] includes an optically transparent conductive sheet comprising the optically transparent conductive layer described in [1] or [2] above and a base layer located on the first main surface side of the optically transparent conductive layer. Effect of the Invention

[0010] The light-transmitting conductive layer of the present invention includes a second region that is crystalline, and therefore has low resistivity. In addition, in the light-transmitting conductive layer, the first region that is amorphous has a non-uniform thickness, and therefore has excellent flexibility.

[0011] The light-transmitting conductive sheet of the present invention includes the light-transmitting conductive layer of the present invention, and therefore has low resistivity and excellent flexibility. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 shows one embodiment of the light-transmitting conductive layer and light-transmitting conductive sheet of the present invention. [Diagram 2] 2A to 2C show one embodiment of a method for producing a light-transmitting conductive layer and a light-transmitting conductive sheet. Fig. 2A shows a first step of preparing a base layer. Fig. 2B shows a third step of arranging a first region on one surface in the thickness direction of the base layer in the second step. Fig. 2C shows a fourth step of arranging a second region on one surface in the thickness direction of the first region in the second step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] With reference to FIG. 1, one embodiment of the light-transmitting conductive layer and light-transmitting conductive sheet of the present invention will be described.

[0014] In FIG. 1, the up-down direction of the paper is the up-down direction (thickness direction). The upper side of the paper is the top side (one side in the thickness direction). The lower side of the paper is the bottom side (the other side in the thickness direction). The left-right direction and the depth direction of the paper are surface directions perpendicular to the up-down direction. Specifically, they follow the directional arrows in each figure.

[0015] The light-transmitting conductive sheet 1 has a film shape (including a sheet shape) having a predetermined thickness. The light-transmitting conductive sheet 1 extends in a plane direction perpendicular to the thickness direction. The light-transmitting conductive sheet 1 has a flat upper surface and a flat lower surface. The light-transmitting conductive sheet 1 is preferably flexible.

[0016] 1, the light-transmitting conductive sheet 1 includes a base layer 2 and a light-transmitting conductive layer 3 disposed on one side in the thickness direction of the base layer 2. In other words, the light-transmitting conductive sheet 1 includes a light-transmitting conductive layer 3 and a base layer 2 located on a first main surface 11 (described later) side of the light-transmitting conductive layer 3. More specifically, the light-transmitting conductive sheet 1 includes a base layer 2 and a light-transmitting conductive layer 3 disposed directly on the upper surface (one side in the thickness direction) of the base layer 2. The light-transmitting conductive sheet 1 preferably includes the base layer 2 and the light-transmitting conductive layer 3.

[0017] The light-transmitting conductive sheet 1 has a thickness of, for example, 400 μm or less, preferably 200 μm or less, and for example, 1 μm or more, preferably 5 μm or more.

[0018] <Base material layer> The base material layer 2 has a film shape. The base material layer 2 is preferably flexible. The base material layer 2 is disposed on the entire lower surface of the light-transmitting conductive layer 3 so as to contact the lower surface of the light-transmitting conductive layer 3. The base material layer 2 is the bottom layer of the light-transmitting conductive sheet 1.

[0019] The substrate layer 2 includes a substrate 10. The substrate layer 2 is made of the substrate 10.

[0020] [Base material] Examples of the substrate 10 include a polymer film and glass. From the viewpoint of flexibility, the substrate 2 is preferably a polymer film.

[0021] Examples of materials for the polymer film include polyester resin, (meth)acrylic resin, olefin resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, and polystyrene resin. Examples of polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of (meth)acrylic resin include polymethyl methacrylate. Examples of olefin resin include polyethylene, polypropylene, and cycloolefin polymer. Examples of cellulose resin include triacetyl cellulose.

[0022] As the material of the polymer film, preferably, a polyester resin is used, and more preferably, polyethylene terephthalate is used.

[0023] The thickness of the substrate 10 is, for example, 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and for example, 200 μm or less, preferably 150 μm or less, more preferably 130 μm or less.

[0024] The thickness of the substrate 10 can be measured using a dial gauge (manufactured by PEACOCK, "DG-205").

[0025] Moreover, the substrate 10 preferably has transparency. Specifically, the total light transmittance (JIS K 7375-2008) of the substrate layer 2 is, for example, 50% or more, preferably 70% or more, more preferably 80% or more, and preferably 85% or more.

[0026] <Light-transparent conductive layer> The light-transmitting conductive layer 3 has a film shape. The light-transmitting conductive layer 3 is disposed over the entire upper surface of the base layer 2 so as to be in contact with the upper surface of the base layer 2. The light-transmitting conductive layer 3 is the uppermost layer of the light-transmitting conductive sheet 1.

[0027] The light-transmitting conductive layer 3 has a first main surface 11 and a second main surface 12 opposed to each other in the thickness direction.

[0028] The first main surface 11 is a flat surface. The first main surface 11 is in contact with one surface of the base layer 2 in the thickness direction.

[0029] The second main surface 12 is exposed to one side in the thickness direction. The second main surface 12 is a flat surface that is approximately parallel to the first main surface 11.

[0030] Examples of materials for the light-transmitting conductive layer 3 include conductive oxides. 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. If necessary, the metal oxide may be doped with a metal atom or metalloid atom shown in the above group.

[0031] Examples of the conductive oxide include metal oxides, such as indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), indium gallium oxide (IGO), indium tin oxide (ITO), and antimony tin oxide (ATO).

[0032] From the viewpoint of improving transparency and electrical conductivity, the conductive oxide is preferably indium tin oxide (ITO). In the following description, the case where the material of the light-transmitting conductive layer 3 is indium tin oxide (ITO) will be described in detail.

[0033] In indium tin oxide (ITO), the concentration of tin oxide is, for example, 0.1 mass% or more, preferably 1 mass% or more, preferably 5 mass% or more, more preferably 10 mass% or more, for example, 30 mass% or less, preferably 15 mass% or less.

[0034] The light-transmitting conductive layer 3 includes a first region 21 and a second region 22 arranged in this order toward one side in the thickness direction.

[0035] [First area] The first region 21 includes the first main surface 11. The first region 21 is the other thickness-wise side portion of the light-transmitting conductive layer 3. The first region 21 includes the other thickness-wise surface of the light-transmitting conductive layer 3. The first region 21 is formed across the entire surface of the light-transmitting conductive layer 3. The first main surface 11 is the other thickness-wise surface of the first region 21.

[0036] The main region of the first region 21 is amorphous. More specifically, the first region 21 includes a region that is amorphous as a main region in a cross-sectional view. Specifically, examples of the form of the first region 21 include a form in which all the regions in the first region 21 are amorphous in a cross-sectional view, and a form in which the main region of the first region 21 is amorphous and the remaining small region is crystalline in a cross-sectional view.

[0037] The amorphous nature of the first region 21 is confirmed by observing a cross-sectional TEM image. In addition, by observing the presence or absence of lattice fringes and the proportion of the region in which lattice fringes are confirmed by high-magnification cross-sectional TEM observation, it is possible to identify that the first region 21 is amorphous and / or that the region is mainly amorphous.

[0038] In addition, in a cross-sectional view, the area ratio of the main region in the first region 21 (amorphous area ratio) is, for example, 0.6 or more, preferably 0.8 or more, more preferably 0.9 or more, and is, for example, 1 or less.

[0039] Moreover, the first region 21 has a non-uniform thickness. Specifically, the first surface 13 on the opposite side to the first main surface 11 in the first region 21 has a non-uniform surface.

[0040] More specifically, the first region 21 has a non-uniform thickness means that the difference between the thickness at the position where the first region 21 is thickest and the thickness at the position where the first region 21 is thinnest in a cross-sectional image of the light-transmitting conductive layer 3 is 5 nm or more. The thickness of the first region 21 is determined from the difference between the first surface 13 and the first main surface 11. This will be described in detail in the examples below.

[0041] Moreover, such a first region 21 can be formed, for example, by setting the water pressure in sputtering, which will be described later, within a predetermined range.

[0042] The minimum thickness of the first region 21 is preferably thinner than the thickness (minimum thickness) of the second region 22 described later, and is, for example, 1 nm or more, preferably 3 nm or more, more preferably 5 nm or more, and for example, 50 nm or less, preferably 30 nm or less, more preferably 20 nm or less.

[0043] Furthermore, the ratio of the thickness (minimum thickness) of the first region 21 to the thickness (minimum thickness) of the light-transmitting conductive layer 3 is, for example, 0.02 or more, preferably 0.04 or more, and for example, 0.10 or less, preferably 0.08 or less, more preferably 0.05 or less.

[0044] If the ratio is within the above range, it is possible to improve the flexibility while maintaining a low resistivity.

[0045] The method for measuring the thickness (minimum thickness) of the first region 21 will be described in detail in the examples described later.

[0046] [Second area] The second region 22 includes the second main surface 12. The second region 22 is a portion on one side in the thickness direction of the light-transmitting conductive layer 3. The second region 22 includes one surface in the thickness direction of the light-transmitting conductive layer 3. The second region 22 is continuous with one side in the thickness direction of the first region 21. The second region 22 is formed across the entire surface direction of the light-transmitting conductive layer 3. The second main surface 12 is one surface in the thickness direction of the second region 22.

[0047] The main region of the second region 22 is crystalline. Specifically, the second region 22 includes a region that is crystalline as a main region in a cross-sectional view. Specifically, examples of the form of such second region 22 include a form in which all the regions in the second region 22 are crystalline in a cross-sectional view, and a form in which the main region of the second region 22 is crystalline and the remaining small region is amorphous in a cross-sectional view.

[0048] The crystallinity of the second region 22 is confirmed by observing a cross-sectional TEM image. In addition, by observing the presence or absence of lattice fringes and the proportion of the region in which lattice fringes are confirmed by high-magnification cross-sectional TEM observation, it is possible to identify that the second region 22 is crystalline and / or that the region is mainly crystalline. In addition, when the second region 22 is crystalline, for example, the second region 22 is immersed in a 5% by mass hydrochloric acid aqueous solution for 15 minutes, washed with water and dried, and the two-terminal resistance is measured over a distance of about 15 mm on the surface of the second region 22, and the two-terminal resistance is 10 kΩ or less.

[0049] In addition, in a cross-sectional view, the area ratio of the main region in the second region 22 (the area ratio of the crystalline material) is, for example, 0.7 or more, preferably 0.8 or more, more preferably 0.9 or more, and is, for example, 1 or less.

[0050] The second region 22 has a non-uniform thickness. Specifically, the second surface 14 on the opposite side to the second main surface 12 in the second region 22 has a non-uniform surface corresponding to the first surface 13 described above.

[0051] Since the second region 22 is disposed on one surface of the first region 21 in the thickness direction, if the first region 21 has a non-uniform thickness, the second region 22 also has a non-uniform thickness.

[0052] From the viewpoints of low resistivity and flexibility, the thickness (minimum thickness) of the second region 22 is preferably thicker than the thickness (minimum thickness) of the first region 21, for example, more than 70 nm, preferably 80 nm or more, more preferably 90 nm or more, and for example, 150 nm or less, preferably 120 nm or less, more preferably 110 nm or less.

[0053] Furthermore, the ratio of the thickness (minimum thickness) of the second region 22 to the thickness (minimum thickness) of the light-transmitting conductive layer 3 is, for example, 0.90 or more, preferably 0.92 or more, more preferably 0.95 or more, and for example, 0.98 or less, preferably 0.96 or less.

[0054] If the ratio is within the above range, it is possible to improve the flexibility while maintaining a low resistivity.

[0055] The method for measuring the thickness (minimum thickness) of the second region 22 will be described in detail in the examples described below.

[0056] If the thickness (minimum thickness) of the second region 22 is greater than the thickness (minimum thickness) of the first region, the flexibility can be further improved.

[0057] The ratio of the thickness (minimum thickness) of the second region 22 to the thickness (minimum thickness) of the first region 21 is, for example, more than 1, preferably 2.0 or more, more preferably 4.0 or more, even more preferably 7 or more, particularly preferably 15 or more, and is, for example, 50 or less, preferably 25 or less.

[0058] If the ratio is within the above range, it is possible to improve the flexibility while maintaining a low resistivity.

[0059] [Physical properties of light-transmitting conductive layer] The thickness (minimum thickness) of the light-transmitting conductive layer 3 is the sum of the thickness of the first region 21 and the thickness of the second region 22, and from the viewpoint of low resistance, is, for example, 80 nm or more, preferably 100 nm or more, and for example, 200 nm or less, preferably 150 nm or less, and more preferably 120 nm or less.

[0060] The total light transmittance (JIS K 7375-2008) of the light transmissible conductive layer 3 is, for example, 60% or more, preferably 80% or more, more preferably 85% or more, and for example, 100% or less.

[0061] The surface resistance of the light-transmitting conductive layer 3 is, for example, 40 Ω / □ or less, preferably 35 Ω / □ or less, and for example, more than 0 Ω / □. The surface resistance can be measured by a four-terminal method in accordance with JIS K7194.

[0062] The resistivity of the light-transmitting conductive layer 3 is, for example, 2.8×10 -4 Ωcm or less, more preferably 2.5×10 -4 Ωcm or less, for example, greater than 0 Ωcm, preferably 0.1×10 -4 Ωcm or more, more preferably 1.0×10 -4 The resistivity is calculated by multiplying the surface resistance by the thickness.

[0063] <Method for producing light-transmitting conductive sheet> A method for producing the light-transmitting conductive sheet 1 will be described with reference to FIGS. 2A to 2C.

[0064] The method for producing the light-transmitting conductive sheet 1 includes a first step of preparing a base layer 2, and a second step of disposing a light-transmitting conductive layer 3 on one surface of the base layer 2 in the thickness direction by a sputtering method. In this method, each layer is disposed in order, for example, by a roll-to-roll method. In such a case, the conveying speed is, for example, 1.0 m / min or more and, for example, 20.0 m / min or less.

[0065] [1st step] In the first step, the base layer 2 is prepared.

[0066] To prepare the substrate layer 2, a substrate 10 is prepared as shown in FIG. 2A.

[0067] [Second process] In the second step, the light-transmitting conductive layer 3 is disposed on one surface of the base layer 2 in the thickness direction by sputtering.

[0068] In detail, the second step includes a third step of arranging a first region 21 on one thickness-wise surface of the base layer 2, a fourth step of arranging a second region 22 on one thickness-wise surface of the first region 21, and a fifth step of crystallizing the second region 22 by heating.

[0069] (3rd step) In the third step, as shown in FIG. 2B, the first region 21 is disposed on one surface in the thickness direction of the base layer 2 by a sputtering method.

[0070] In order to dispose the first region 21 on one surface in the thickness direction of the base layer 2 by the sputtering method, the one surface in the thickness direction of the base layer 2 is subjected to a surface treatment, if necessary.

[0071] Examples of the surface treatment include corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, and saponification treatment.

[0072] Next, in the sputtering method, a target (material of the first region 21) and the base layer 2 are placed facing each other in a vacuum chamber. In the sputtering, the base layer 2 is in close contact with the film-forming roll along the circumferential direction.

[0073] Next, a sputtering gas is supplied and a voltage is applied from a power source to accelerate the gas ions and irradiate the target, thereby ejecting the target material from the target surface. The target material is then deposited on the surface (one surface in the thickness direction) of the base layer 2 to form the first region 21.

[0074] Examples of the sputtering gas include an inert gas (e.g., krypton gas, argon gas) and oxygen gas. As the sputtering gas, preferably, an inert gas and an oxygen gas are used in combination. As the inert gas, preferably, argon gas is used. When argon gas is used as the inert gas, the first region 21 contains argon atoms.

[0075] The amount of oxygen gas introduced is, for example, 1.0 flow % or more, preferably 2.0 flow % or more, and for example, 5.0 flow % or less, preferably 3.0 flow % or less, based on the total amount of inert gas and oxygen gas.

[0076] The air pressure during sputtering is, for example, 0.1 Pa or more, preferably 0.2 Pa or more, and for example, 2.0 Pa or less, preferably 1.0 Pa or less.

[0077] The water pressure during sputtering is, for example, 0.5×10 -4 Pa, preferably 0.6 x 10 -4 Pa or more, more preferably 0.6×10 -4 Pa or more, for example, 1.8×10 -4 Pa or less, preferably 1.5×10 -4 Pa or less, more preferably 1.0×10 -4 Pa or less.

[0078] If the water pressure during sputtering is within the above range, the first region 21 having a non-uniform thickness can be reliably formed.

[0079] Furthermore, if the water pressure during sputtering is within the above range, the first region 21 can be maintained amorphous in the fifth step.

[0080] The power source may be, for example, a DC power source, an AC power source, an MF power source, or an RF power source, or may be a combination of these.

[0081] The discharge output is, for example, 1.0 kW or more, preferably 10.0 kW or more, and for example, 20 kW or less.

[0082] The horizontal magnetic field strength of the target is, for example, 10 mT or more, preferably 20 mT or more, and for example, 100 mT or less, preferably 50 mT or less.

[0083] The temperature of the film-forming roll is, for example, 20° C. or lower, preferably 10° C. or lower, more preferably 0° C. or lower, and for example, −50° C. or higher, preferably −25° C. or higher.

[0084] (4th step) In a fourth step, as shown in FIG. 2C, the second region 22 is disposed on one surface of the first region 21 in the thickness direction by a sputtering method.

[0085] Next, in the sputtering method, a target (material of the second region 22) and the first region 21 are placed facing each other in a vacuum chamber. Next, sputtering gas is supplied and a voltage is applied from a power source to accelerate gas ions and irradiate the target, thereby ejecting the target material from the target surface. Then, the target material is deposited on the surface (one surface in the thickness direction) of the first region 21 to form the second region 22. In addition, in the sputtering, the base layer 2 is in close contact with the film-forming roll along the circumferential direction.

[0086] Examples of the sputtering gas include an inert gas (e.g., krypton gas, argon gas) and oxygen gas. The inert gas is preferably argon gas. When argon gas is used as the inert gas, the second region 22 contains argon atoms.

[0087] The amount of oxygen gas introduced is, for example, 0.05 flow % or more, preferably 0.1 flow % or more, and for example, 5.0 flow % or less, preferably 3.0 flow % or less, based on the total amount of inert gas and oxygen gas.

[0088] The air pressure during sputtering is, for example, 0.1 Pa or more, preferably 0.2 Pa or more, and for example, 2.0 Pa or less, preferably 1.0 Pa or less.

[0089] The water pressure during sputtering is preferably higher than that in the third step, for example, 1.8×10 -4 Pa or more, preferably 2.0 x 10 -4 Pa or more, for example, 4.0×10 -4 Pa or less, preferably 3.0×10 -4 Pa or less, more preferably 2.5×10 -4 Pa or less.

[0090] If the water pressure during sputtering is within the above range, the second region 22 can be reliably crystallized in the fifth step.

[0091] The power source may be, for example, a DC power source, an AC power source, an MF power source, or an RF power source, or may be a combination of these.

[0092] The discharge output is, for example, 1.0 kW or more, preferably 10.0 kW or more, and for example, 20 kW or less.

[0093] The horizontal magnetic field strength of the target is, for example, 10 mT or more, and, for example, 200 mT or less, preferably 100 mT or less, and more preferably 40 mT or less.

[0094] The temperature of the film-forming roll is, for example, 20° C. or lower, preferably 10° C. or lower, more preferably 0° C. or lower, and for example, −50° C. or higher, preferably −25° C. or higher.

[0095] (5th step) In the fifth step, the second region 22 is crystallized by heating.

[0096] To crystallize the second region 22, the second region 22 is heated. Specifically, after sputtering, the second region 22 is heated using a heating roll.

[0097] As for the heating conditions, the heating temperature is, for example, 100° C. or more, preferably 120° C. or more, and for example, 250° C. or less, preferably 200° C. or less; and the heating time is, for example, 10 minutes or more, and for example, 120 minutes or less.

[0098] As a result, the second region 22 crystallizes. On the other hand, the first region 21 does not crystallize and remains amorphous. In detail, if the water pressure in the third step is within the above range, the combined amount of impurity gas derived from rare gas and water reaches a suitable level for maintaining the amorphous state, and the first region 21 does not crystallize and remains amorphous. Also, if the water pressure in the fourth step is within the above range, the amount of impurities is sufficient to obtain crystallinity, and the second region 22 crystallizes.

[0099] In this manner, the light-transmitting conductive sheet 1 is obtained.

[0100] <Action and effect> The light-transmitting conductive layer 3 includes a crystalline second region 22. Therefore, the light-transmitting conductive layer 3 has a low resistivity. Furthermore, in the light-transmitting conductive layer 3, the amorphous first region 21 has a non-uniform thickness. Therefore, the light-transmitting conductive layer 3 has excellent flexibility.

[0101] Specifically, when the amorphous first region 21 in the light-transmitting conductive layer 3 has a non-uniform thickness, the stress caused by bending is alleviated by the first region 21. As a result, the bending property can be improved.

[0102] The light-transmitting conductive sheet 1 includes a light-transmitting conductive layer 3. Therefore, the sheet has low resistivity and excellent flexibility.

[0103] <Modification> In the modified example, the same reference numerals are used for the same components and steps as those in the first embodiment, and detailed descriptions thereof will be omitted. In addition, the modified example can achieve the same effects as those in the first embodiment, unless otherwise specified. Furthermore, the first embodiment and its modified example can be appropriately combined.

[0104] In the above description, the base layer 2 is made of the base material 10, but the base layer 2 may further include a cured resin layer. In such a case, the base layer 2 includes the base material 10 and the cured resin layer in this order toward one side in the thickness direction.

[0105] The cured resin layer includes a dielectric layer and a hard coat layer.

[0106] In addition, in the above description, the crystalline state of the first region 21 and the second region 22 is adjusted by adjusting the water pressure in the third and fourth steps within a predetermined range. However, for example, the crystalline state of the first region 21 and the second region 22 can also be adjusted by adjusting the power density in the third and fourth steps within a predetermined range.

[0107] In the above description, the first surface 13 on the opposite side to the first main surface 11 in the first region 21 has an uneven surface, but the first surface 13 may not have an uneven surface (i.e., have a flat surface) and the first main surface 11 may have an uneven surface. Even in such a case, the first region 21 has an uneven thickness. Also, in such a case, the second surface 14 in the second region 22 has a flat surface.

[0108] In addition, in the first region 21, the first main face 11 and the first surface 13 may have a non-uniform surface. Even in such a case, the first region 21 has a non-uniform thickness. In addition, in such a case, the second surface 14 in the second region 22 has a non-uniform surface.

[0109] Preferably, from the viewpoint of improving the bendability, in the first region 21, the first surface 13 has an uneven surface, and the first main surface 11 has a flat surface. In such a case, in the second region 22, the second surface 14 in the second region 22 has an uneven surface. EXAMPLES

[0110] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the examples and comparative examples. The specific numerical values ​​of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values ​​(numerical values ​​defined as "less than or equal to" or "less than") or lower limit values ​​(numerical values ​​defined as "more than or equal to" or "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Form for carrying out the invention".

[0111] <Production of Light-Transmitting Conductive Layer and Light-Transmitting Conductive Sheet> Example 1 [1st step] A long PET film (thickness: 125 μm, manufactured by Mitsubishi Chemical Corporation) was prepared as a substrate, thereby preparing a substrate layer.

[0112] [Second process] A light-transmitting conductive layer was disposed on one surface of the base layer in the thickness direction by a reactive sputtering method. In the reactive sputtering method, a sputtering deposition apparatus (DC magnetron sputtering apparatus) capable of performing a deposition process by a roll-to-roll method was used. (3rd step) Specifically, first, the first region was disposed on one surface in the thickness direction of the base layer.

[0113] Specifically, a sintered body of indium oxide and tin oxide (tin oxide concentration: 12.5% ​​by mass) was used as the target. A DC power supply was used as the power supply for applying a voltage to the target. The horizontal magnetic field strength on the target was 30 mT. In the sputtering device, the base material layer was brought into close contact with the film-forming roll along the circumferential direction. The temperature of the film-forming roll was set to -5°C. The ultimate vacuum in the film-forming chamber of the sputtering film-forming device was 0.9×10 -4 After evacuating the inside of the sputtering film formation apparatus until the pressure reached 0.2 Pa, argon as a sputtering gas and oxygen as a reactive gas were introduced into the sputtering film formation apparatus, and the pressure inside the sputtering film formation apparatus was set to 0.2 Pa. In addition, the water pressure during sputtering was 0.8×10 -4 Sputtering was carried out in an environment of 10 Pa. The ratio of the amount of oxygen introduced to the total amount of argon and oxygen introduced into the sputtering deposition device was approximately 2.4 flow %. As a result, a first region (thickness 5 to 20 nm (minimum thickness 5 nm)) was disposed on one surface in the thickness direction of the base layer.

[0114] (4th step) The second region was disposed on one surface in the thickness direction of the first region.

[0115] Specifically, a sintered body of indium oxide and tin oxide (tin oxide concentration: 12.5% ​​by mass) was used as the target. A DC power supply was used as the power supply for applying a voltage to the target. The horizontal magnetic field strength on the target was 30 mT. In the sputtering device, the base material layer was brought into close contact with the film-forming roll along the circumferential direction. The temperature of the film-forming roll was set to -5°C. The ultimate vacuum in the film-forming chamber of the sputtering film-forming device was 0.9×10 -4 After evacuating the inside of the sputtering film formation apparatus until the pressure reached 0.2 Pa, argon as a sputtering gas and oxygen as a reactive gas were introduced into the sputtering film formation apparatus, and the pressure inside the sputtering film formation apparatus was set to 0.2 Pa. In addition, the water pressure during sputtering was 2.1×10 -4Sputtering was performed in an environment of 0.1 Pa. The ratio of the amount of oxygen introduced to the total amount of argon and oxygen introduced into the sputtering deposition device was approximately 2.3 flow %. As a result, a second region (thickness 100 to 120 nm (minimum thickness 100 nm)) was disposed on one surface in the thickness direction of the first region.

[0116] (5th step) The second region was crystallized by heating. Specifically, it was heated in a hot air oven. The heating temperature was 140°C, and the heating time was 30 minutes. This caused the second region to crystallize. Meanwhile, the first region was not crystallized and remained amorphous. In this way, a light-transmitting conductive layer and a light-transmitting conductive sheet 1 were manufactured.

[0117] Comparative Example 1 A light-transmitting conductive layer and a light-transmitting conductive sheet were produced according to the same procedure as in Example 1. However, the water pressure in the third step was set to 0.5×10 -4 Changed to Pa.

[0118] Comparative Example 2 A light-transmitting conductive layer and a light-transmitting conductive sheet were produced according to the same procedure as in Example 1, except that the third step was not carried out.

[0119] Comparative Example 3 A light-transmitting conductive layer and a light-transmitting conductive sheet were produced according to the same procedure as in Example 1, except that the fifth step was not carried out.

[0120] <Evaluation> [Thickness of light-transmitting conductive layer] The thickness of the light-transmitting conductive layer (each region) of each Example and Comparative Example was measured by FE-TEM observation. Specifically, first, a cross-sectional observation sample of the light-transmitting conductive layer of each Example and Comparative Example was prepared by FIB microsampling. In the FIB microsampling method, a 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, a FE-TEM device (trade name "JEM-2800", manufactured by JEOL) was used, and the acceleration voltage was set to 200 kV.

[0121] The thickness of the second region was calculated by subtracting the thickness of the first region from the thickness of the entire light-transmitting conductive layer. The results are shown in Table 1.

[0122] [Checking whether the first region 2 has an uneven thickness] In the same manner as in the evaluation of the thickness of the light-transmitting conductive layer, the cross-sectional image of the FE-TEM was confirmed. At an observation magnification of 500,000 times (photographing range: horizontal length 275 nm), it was confirmed that the difference in thickness between the thickest position of the first region 2 and the thinnest position of the first region 21 was 5 nm or more in Example 1, and it was determined that the first region 2 had a non-uniform thickness.

[0123] [Resistance value] The resistance value (R0) of the light-transmitting conductive layer of each Example and Comparative Example was measured by a four-terminal method. The resistance value was evaluated based on the following criteria. The results are shown in Table 1. {standard} ○: The resistance value was 40Ω / □ or less. ×: The resistance value exceeded 40 Ω / □.

[0124] [Flexibility] The light-transmitting conductive sheets of each Example and Comparative Example were evaluated for their flexibility. Specifically, the light-transmitting conductive sheets of each Example and Comparative Example were cut to a width of 10 mm and a length of 150 mm to prepare samples. Then, the samples were placed on the mandrel so that the light-transmitting conductive layer was on the outside and the other surface of the substrate in the thickness direction was in contact with the mandrel. Then, both ends of the light-transmitting conductive sheet in the longitudinal direction were fastened with clips, and a weight of 1000 g was attached to the center of the clips. That is, a load of 100 g / mm was applied downward relative to the width of the light-transmitting conductive sheet to fold the light-transmitting conductive sheet. This folded state was maintained for 10 seconds.

[0125] In this bent state, the bent portion was painted with a marker, and then the bent portion was released and the marker was observed under a microscope. In this test method, the diameter of the mandrel was changed from large to small in 1 mm increments, and the smallest diameter at which no cracks were observed under the microscope in the marker-painted portion was recorded in Table 1. The smaller this value, the better the bending resistance. The results are shown in Table 1.

[0126] In the above test, the mandrel diameter was changed from large to small in increments of 1 mm, and the sample was changed for each change. In other words, in the above test, each sample was bent once, and each time it was bent, a different sample (a different sample manufactured under the same conditions) was used.

[0127] [Table 1] [Explanation of symbols]

[0128] 1. Light-transmitting conductive sheet 2 Base material layer 3 Light-transparent conductive layer 11 First main surface 12 Second main surface 21 First area 22 Second area

Claims

1. A light-transmitting conductive sheet comprising a light-transmitting conductive layer and a polymer film substrate layer, The light-transmitting conductive layer is The substrate has a first main surface and a second main surface opposed to each other in a thickness direction, A first region including the first main surface and a second region including the second main surface are provided in this order toward one side in a thickness direction, a major portion of the first region is an amorphous conductive oxide; a major portion of the second region is a crystalline conductive oxide; the first region has a non-uniform thickness; The polymer film substrate layer is located on the first main surface side of the light-transmitting conductive layer.

2. The optically transparent conductive sheet according to claim 1 , wherein the second region has a thickness greater than a thickness of the first region.

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