Transparent conductive layer, transparent conductive sheet, touch sensor, light-adjusting element, photoelectric conversion element, heat ray control member, antenna, electromagnetic wave shielding member, and image display device

Abstract

The transparent conductive layer 3 includes: a first main surface 5 exposed to the outside, and a second main surface 6 opposite to the first main surface 5 in the thickness direction. The transparent conductive layer 3 is a single layer extending in the plane direction. The transparent conductive layer 3 includes: a first grain boundary 7 in which both end edges 23 are open to the first main surface 5 in the cross-sectional view, and an intermediate region 25 between the two end edges 23 is not in contact with the second main surface 6; and a first crystal grain 31 separated by the first grain boundary 7 and facing only the first surface 5.

Description

Technical Field

[0001] The present invention relates to a transparent conductive layer, a transparent conductive sheet, a touch sensor, a light-adjusting element, a photoelectric conversion element, a heat ray control member, an antenna, an electromagnetic wave shielding member and an image display device. Background Art

[0002] Conventionally, there is known a transparent conductive sheet including a crystalline transparent conductive layer.

[0003] For example, a light-transmitting conductive film including a light-transmitting conductive layer having a plurality of crystal grains has been proposed (for example, refer to Patent Document 1 listed below).

[0004] In the light-transmitting conductive layer described in Patent Document 1, the grain boundaries separating the plurality of crystal grains described above exist from the upper surface to the lower surface of the light-transmitting conductive layer.

[0005] In addition, the light-transmitting conductive layer of Patent Document 1 is formed into a wiring pattern by etching.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-41059 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] The light-transmitting conductive layer is sometimes etched for reasons such as wiring pattern formation and appearance. In recent years, in order to improve the productivity of the etching process, a high etching rate is required for the light-transmitting conductive layer. However, the light-transmitting conductive layer described in Patent Document 1 sometimes cannot meet the above requirements.

[0011] The present invention provides a transparent conductive layer with a high etching rate, a transparent conductive sheet, a touch sensor, a light-adjusting element, a photoelectric conversion element, a heat ray control member, an antenna, an electromagnetic wave shielding member and an image display device.

[0012] Solutions for solving problems

[0013] The present invention (1) comprises a transparent conductive layer, which comprises: a first main surface exposed to the outside, and a second main surface opposite to the first main surface in the thickness direction, wherein the transparent conductive layer is a single layer extending in a plane direction perpendicular to the thickness direction, and the transparent conductive layer has: a grain boundary in which both end edges in a cross-sectional view are open to the first main surface and an intermediate region between the two end edges does not contact the second main surface; and a first crystal grain separated by the grain boundary and facing only the first main surface.

[0014] When the etching liquid contacts the first main surface of the transparent conductive layer, the etching liquid easily penetrates into the grain boundaries from the two edges, so that the first crystal grains separated by the grain boundaries are easily peeled off. As a result, the etching rate of the transparent conductive layer is high.

[0015] The present invention (2) comprises the transparent conductive layer according to (1), further comprising a second grain boundary, the second grain boundary being open to a side surface connecting one end edge of the first main surface and one end edge of the second main surface.

[0016] When the etching liquid contacts the side surface of the transparent conductive layer, the etching liquid easily penetrates into the second grain boundary, so that the crystal grains separated by the second grain boundary are easily peeled off. As a result, the etching rate of the transparent conductive layer is further increased.

[0017] The present invention (3) comprises the transparent conductive layer described in (1) or (2), wherein the material of the transparent conductive layer is an oxide containing tin.

[0018] The material of the transparent conductive layer is an oxide containing tin, and thus the transparent conductive layer has excellent transparency and conductivity.

[0019] The present invention (4) includes a transparent conductive sheet comprising: the transparent conductive layer according to any one of (1) to (3); and a base sheet located on the second main surface side of the transparent conductive layer.

[0020] The present invention (5) includes a touch sensor comprising the transparent conductive layer according to any one of (1) to (3).

[0021] The present invention (6) includes a light control element including the transparent conductive layer according to any one of (1) to (3).

[0022] The present invention (7) includes a photoelectric conversion element comprising the transparent conductive layer according to any one of (1) to (3).

[0023] The present invention (8) includes a heat ray controlling member comprising the transparent conductive layer according to any one of (1) to (3).

[0024] The present invention (9) includes an antenna comprising the transparent conductive layer according to any one of (1) to (3).

[0025] The present invention (10) includes an electromagnetic wave shielding member comprising the transparent conductive layer according to any one of (1) to (3).

[0026] The present invention (11) includes an image display device comprising the transparent conductive layer according to any one of (1) to (3).

[0027] Effects of the Invention

[0028] The transparent conductive layer included in the transparent conductive sheet, touch sensor, light control element, photoelectric conversion element, heat ray control member, antenna, electromagnetic wave shielding member and image display device of the present invention has a high etching rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 middle, Figure 1 A~ Figure 1 C is a cross-sectional view of a process for explaining a method for producing an embodiment of a transparent conductive sheet of the present invention, Figure 1 A is a step of preparing a substrate sheet, Figure 1 B is a step of forming an amorphous transparent conductive layer, Figure 1 C is a step of forming a crystalline transparent conductive layer.

[0030] Figure 2 for Figure 1 FIG. 3 is an enlarged cross-sectional view of one end portion of the transparent conductive layer in the transparent conductive sheet shown in FIG.

[0031] Figure 3 for Figure 1 B is a schematic diagram of a sputtering device used in the step of forming an amorphous transparent conductive layer.

[0032] Figure 4 It is a cross-sectional view of a modification of the transparent conductive layer of the present invention (a modification in which the fourth crystal grains are separated by two third crystal boundaries).

[0033] Figure 5 It is a cross-sectional view of a modification of the transparent conductive layer of the present invention (including a modification in which the fifth crystal grain faces none of the first main surface, the second main surface, and the side surface).

[0034] Figure 6 It is a cross-sectional view of a modification of the transparent conductive layer of the present invention (a modification in which the first grain boundary does not include a branch point).

[0035] Figure 7 It is a cross-sectional view of a modification of the transparent conductive sheet of the present invention (a modification including a functional layer).

[0036] Figure 8 It is a cross-sectional view of a transparent conductive layer not including the first crystal grains in the transparent conductive sheets of Comparative Examples 1 and 2. DETAILED DESCRIPTION

[0037] Reference Figure 1 A~ Figure 3 An embodiment of the transparent conductive sheet of the present invention is described. Figure 2In the figure, the plurality of crystal grains 4 are depicted in grays of different concentrations in order to clearly show the plurality of crystal grains 4 (described later) and to distinguish the first grain boundary 7 (described later) to the third grain boundary 9 (described later) from the lead lines.

[0038] like Figure 1 As shown in C, the transparent conductive sheet 1 has a predetermined thickness and has a sheet shape extending in a plane direction perpendicular to the thickness direction. The transparent conductive sheet 1 includes a base sheet 2 and a transparent conductive layer 3 in this order toward one side in the thickness direction.

[0039] The substrate sheet 2 is a transparent substrate for ensuring the mechanical strength of the transparent conductive sheet 1. The substrate sheet 2 extends in the surface direction. The substrate sheet 2 has a substrate first main surface 21 and a substrate second main surface 22. The substrate first main surface 21 is a flat surface. The substrate second main surface 22 is arranged relative to the substrate first main surface 21 at a distance from the other side in the thickness direction. It should be noted that the substrate sheet 2 is located on the second main surface 6 (described later) side of the transparent conductive layer 3. The substrate second main surface 22 is parallel to the substrate first main surface 21.

[0040] The flat surface may refer to a surface in which the first substrate main surface 21 and the second substrate main surface 22 of the substrate sheet 2 are substantially parallel planes. For example, minute irregularities and ripples to an extent that cannot be observed are permitted.

[0041] As the material of the substrate sheet 2, polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, (meth) acrylic resins such as polymethacrylate (acrylic resins and / or methacrylic resins), olefin resins such as polyethylene, polypropylene, and cycloolefin polymers, polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, polyamide resins, polyimide resins, cellulose resins, polystyrene resins, norbornene resins, etc. can be cited. From the viewpoint of transparency and moisture permeability resistance, polyester resins can be cited preferably, and PET can be cited more preferably. The thickness of the substrate sheet 2 is, for example, 10 μm or more, and, for example, 100 μm or less.

[0042] The transparent conductive layer 3 is arranged on one side in the thickness direction of the substrate sheet 2. Specifically, the transparent conductive layer 3 is in contact with the entire surface of the substrate first main surface 21 of the substrate sheet 2. The transparent conductive layer 3 is a single layer having a predetermined thickness and extending in the surface direction. Specifically, the transparent conductive layer 3 is not a plurality of layers stacked in the thickness direction. More specifically, a plurality of transparent conductive layers separated in the surface direction and including a boundary parallel to the substrate first main surface 21 of the substrate sheet 2 are not the transparent conductive layers of the present invention.

[0043] The transparent conductive layer 3 includes a first main surface 5, a second main surface 6, and a side surface 55 (see Figure 2).

[0044] The first main surface 5 is exposed to one side (outside) in the thickness direction. That is, the first main surface 5 is exposed to the atmosphere. The first main surface 5 is a flat surface.

[0045] The second main surface 6 is disposed opposite to the first main surface 5 at a distance from the other side in the thickness direction. The second main surface 6 is a flat surface parallel to the first main surface 5. The second main surface 6 is in contact with the first main surface 21 of the substrate.

[0046] It should be noted that the flat surface may refer to a plane in which the first main surface 5 and the second main surface 6 are substantially parallel.

[0047] For example, minute irregularities and ripples that are not noticeable are permitted.

[0048] like Figure 2 As shown, the side surface 55 connects the peripheral edge of the first main surface 5 and the peripheral edge of the second main surface 6. In the cross-sectional view, the side surface 55 has: a side surface 56 connecting one end edge of the first main surface 5 and one end edge of the second main surface 6, and another side surface (not shown) connecting the other end edge of the first main surface 5 and the other end edge of the second main surface 6.

[0049] The transparent conductive layer 3 is crystalline. Specifically, the transparent conductive layer 3 does not contain an amorphous region in the plane direction, but only contains a crystalline region. It should be noted that the transparent conductive layer 3 containing an amorphous region is identified by, for example, observing the crystal grains in the plane direction of the transparent conductive layer 3 using TEM.

[0050] In addition, when the transparent conductive layer 3 is crystalline, for example, after the transparent conductive layer 3 is immersed in a 5% by mass hydrochloric acid aqueous solution at 20° C. for 15 minutes, it is washed with water and dried, and the two-terminal resistance between about 15 mm on the first main surface 5 is measured, and the two-terminal resistance is 10 kΩ or less. On the other hand, when the above-mentioned two-terminal resistance exceeds 10 kΩ, the transparent conductive layer 3 is amorphous.

[0051] The transparent conductive layer 3 has a plurality of crystal grains 4. The crystal grains 4 are sometimes referred to as grains. The crystal grains 4 include first crystal grains 31 separated by first grain boundaries 7 as an example of grain boundaries.

[0052] The first crystal grain 31 does not face the second main surface 6 and the side surface 55 but faces the first main surface 5 . That is, the first crystal grain 31 faces only the first main surface 5 .

[0053] The first grain boundary 7 includes two end edges 23. In addition, the two end edges 23 are both open on the first main surface 5. In the first grain boundary 7, the middle area 25 between the two end edges 23 does not contact the second main surface 6 and the side surface 55. The first grain boundary 7 has a roughly U-shaped shape open to one side in the thickness direction in the cross-sectional view. In addition, the first grain boundary 7 has the following path: advancing from one end edge 23 toward the other side in the thickness direction, in the middle of the thickness direction, advancing in the width direction (an example of a direction orthogonal to the thickness direction), and then returning to the other end edge 23 on one side in the thickness direction. It should be noted that the first grain boundary 7 may also have the following path: advancing from one end edge 23 toward the other side in the thickness direction, turning back in the middle of the thickness direction, and returning to the other end edge 23 on one side in the thickness direction.

[0054] Although not shown, a plurality of first crystal grains 31 may be provided in the transparent conductive layer 3. In this case, the first crystal grains 31 adjacent to each other may have one end edge 23 in common.

[0055] Furthermore, in this embodiment, the intermediate region 25 of the first grain boundary 7 includes a first branch point 26 and a second branch point 27 .

[0056] The second grain boundary 8 branches from the first grain boundary 7 starting from the first branch point 26. In addition, one end edge of the second grain boundary 8 is included in the intermediate region 25, and the other end edge is open to the one side surface 56 (side surface 55).

[0057] Furthermore, the second crystal grains 32 are separated by the portion of the first grain boundary 7 extending from the one end edge 23 to the middle portion of the intermediate region 25 and the second grain boundary 8 .

[0058] The second crystal grain 32 does not face the second main surface 6 but faces the first main surface 5 and the one side surface 56. That is, the second crystal grain 32 faces only the first main surface 5 and the one side surface 56.

[0059] In addition, the third grain boundary 9 branches from the first grain boundary 7 starting from the second branch point 27. One end edge of the third grain boundary 9 is included in the intermediate region 25, and the other end edge is open to the second main surface 6. In addition, the third grain 33 is separated by the third grain boundary 9, the intermediate region 25 of the first grain boundary 7, and the second grain boundary 8.

[0060] The third crystal grain 33 does not face the first main surface 5 but faces the second main surface 6 and the one side surface 56. That is, the third crystal grain 33 faces only the second main surface 6 and the one side surface 56.

[0061] Furthermore, the transparent conductive layer 3 may include fourth crystal grains 44 facing both the first main surface 5 and the second main surface 6 .

[0062] The transparent conductive layer 3 only needs to be a crystalline layer including the first crystal grains 31 , and the abundance ratio of the first crystal grains 31 to other crystal grains such as the second crystal grains 32 , the third crystal grains 33 , and the fourth crystal grains 44 may be arbitrary.

[0063] The material of the transparent conductive layer 3 is not particularly limited. As the material of the transparent conductive layer 3, for example, a metal oxide containing at least one metal selected from the group consisting of In, Sn, Zn, Ga, Sb, Nb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W can be cited. Specifically, metal oxides such as indium zinc composite oxide (IZO), indium gallium zinc composite oxide (IGZO), indium gallium composite oxide (IGO), indium tin composite oxide (ITO), and antimony tin composite oxide (ATO) are preferably cited, and tin-containing oxides such as indium tin composite oxide (ITO) and antimony tin composite oxide (ATO) are preferably cited. When the material of the transparent conductive layer 3 is a tin-containing oxide, transparency and conductivity are excellent.

[0064] The content of tin oxide (SnO2) in the transparent conductive layer 3 (tin-containing oxide) is not particularly limited, and is, for example, 0.5 mass % or more, preferably 3 mass % or more, more preferably 6 mass % or more, and, for example, less than 50 mass %, preferably 25 mass % or less, more preferably 15 mass % or less.

[0065] The thickness of the transparent conductive layer 3 is, for example, 10 nm or more, preferably 30 nm or more, more preferably 70 nm or more, further preferably 100 nm or more, particularly preferably 120 nm or more, and most preferably 140 nm or more, and is, for example, 300 nm or less, preferably 200 nm or less. The method for determining the thickness of the transparent conductive layer 3 is described in detail in the following examples.

[0066] The ratio of the length between the two edges 23 in the cross-sectional view (the average length when there are a plurality of first crystal grains 31) to the thickness of the transparent conductive layer 3 is, for example, 0.1 or more, preferably 0.25 or more, and for example, 20 or less, preferably 10 or less, more preferably 5 or less, and further preferably 3 or less. When the ratio exceeds the lower limit and is less than the upper limit, the etching speed of the transparent conductive layer 3 can be increased.

[0067] The maximum crystal grain size of the plurality of crystal grains 4 is not particularly limited, and is, for example, 500 nm or less, preferably 400 nm or less, more preferably 350 nm or less, further preferably 300 nm or less, particularly preferably 250 nm or less, and most preferably 220 nm or less, and, for example, 1 nm or more, preferably 10 nm or more. When the maximum crystal grain size of the plurality of crystal grains 4 is below the above-mentioned upper limit, the amount of the first grain boundary 7 per unit area of ​​the first main surface 5 of the transparent conductive layer 3 can be increased, and therefore, the etching speed can be increased. The method for obtaining the maximum crystal grain size of the plurality of crystal grains 4 is described in detail in the following embodiments.

[0068] The surface resistance of the transparent conductive layer 3 is, for example, 200 Ω / □ or less, preferably 50 Ω / □ or less, more preferably 30 Ω / □ or less, further preferably 20 Ω / □ or less, particularly preferably 15 Ω / □ or less, and, for example, exceeds 0 Ω / □.

[0069] The total light transmittance of the transparent conductive layer 3 is, for example, 50% or more, preferably 75% or more, more preferably 80% or more, further preferably 83% or more, particularly preferably 90% or more, and is, for example, 100% or less.

[0070] Next, a method for producing the transparent conductive sheet 1 will be described.

[0071] In this method, for example, the transparent conductive layer 3 is formed while the base sheet 2 is conveyed by a roll-to-roll method.

[0072] like Figure 1 As shown in A of FIG. 1 , specifically, first, a base sheet 2 is prepared.

[0073] like Figure 1 As shown in C, a transparent conductive layer 3 is then formed on the first main surface 21 of the substrate sheet 2. The transparent conductive layer 3 is formed by a dry method such as sputtering or a wet method such as plating. The transparent conductive layer 3 is preferably formed by a dry method, more preferably by sputtering.

[0074] The method for producing the transparent conductive layer 3 is not particularly limited. For example, a sputtering device 30 (see FIG. 1 ) having a film-forming roller 40 with a cooling device (not shown) is used. Figure 3 ),form Figure 1 The amorphous transparent conductive layer 28 shown in B is then heated.

[0075] like Figure 3 As shown, such a sputtering device 30 includes a feeding section 35 , a sputtering section 36 , and a winding section 37 in this order from the upstream side to the downstream side in the conveyance direction of the base sheet 2 .

[0076] The feeding section 35 includes a feeding roller 38 .

[0077] The sputtering unit 36 ​​includes a film-forming roller 40 and a plurality of targets 41 to 42 .

[0078] The film-forming roller 40 includes a cooling device (not shown) configured to cool the film-forming roller 40 .

[0079] The plurality of targets 41 and 42 include a first target 41 and a second target 42. The first target 41 and the second target 42 are arranged in this order along the circumferential direction of the film-forming roll 40.

[0080] As materials of the targets 41 and 42 , the same materials as those of the transparent conductive layer 3 described above can be mentioned.

[0081] The plurality of targets 41 to 42 are respectively housed in the plurality of film forming chambers 51 to 52 .

[0082] The plurality of film forming chambers 51 and 52 include a first film forming chamber 51 and a second film forming chamber 52. The first film forming chamber 51 to the second film forming chamber 52 are disposed adjacent to each other in the circumferential direction.

[0083] A plurality of gas supply machines 61 to 62 are provided in each of the plurality of film forming chambers 51 to 52. The plurality of gas supply machines 61 to 62 correspond to the plurality of targets 41 to 42, respectively. The plurality of gas supply machines 61 to 62 include a first gas supply machine 61 and a second gas supply machine 62. The plurality of gas supply machines 61 to 62 can supply sputtering gas to each of the plurality of film forming chambers 51 to 52.

[0084] Specifically, each of the plurality of gas supply devices 61 to 62 includes inert gas supply devices 61A to 62A and oxygen gas supply devices 61B to 62B.

[0085] The inert gas supply devices 61A to 62A include a first inert gas supply device 61A and a second inert gas supply device 62A. The first inert gas supply device 61A to the second inert gas supply device 62A can supply inert gas to each of the plurality of film forming chambers 51 to 52 .

[0086] The oxygen gas supply machines 61B to 62B include a first oxygen gas supply machine 61B and a second oxygen gas supply machine 62B. The first oxygen gas supply machine 61B to the second oxygen gas supply machine 62B can supply oxygen gas to each of the plurality of film forming chambers 51 to 52 .

[0087] In addition, each of the plurality of film forming chambers 51 to 52 is provided with a pump 50 capable of reducing the pressure of each of the plurality of film forming chambers 51 to 52 .

[0088] The winding section 37 includes a winding roller 39 .

[0089] When the amorphous transparent conductive layer 28 is formed (sputtered) on the substrate first main surface 21 of the substrate sheet 2 using the sputtering device 30 , first, the substrate sheet 2 is laid between the feeding roll 38 , the film forming roll 40 , and the winding roll 39 .

[0090] In addition, the cooling device is driven to cool the film-forming roller 40 (the surface). The temperature (surface temperature) of the film-forming roller 40 is, for example, 10.0°C or less, preferably 0.0°C or less, more preferably -2.5°C or less, further preferably -5.0°C or less, further preferably -7.0°C or less, and, for example, -50°C or more, preferably -20°C or more, further preferably -10°C or more. When the temperature of the film-forming roller 40 is below the above upper limit, the substrate sheet 2 can be sufficiently cooled, and the first grain boundary 7 can be formed in the transparent conductive layer 3. In detail, excessive heat is not applied during the film formation of the transparent conductive layer 3, so that excessive growth of the crystal grains 4 in the thickness direction and the surface direction when converted into crystalline can be suppressed. Therefore, the first grain boundary 7 is formed in the transparent conductive layer 3.

[0091] On the other hand, when the temperature of the film-forming roller 40 is equal to or higher than the above lower limit, the amorphous transparent conductive layer 28 that can be converted into a crystalline transparent conductive layer can be formed from the amorphous transparent conductive layer.

[0092] Furthermore, the plurality of pumps 50 are driven to evacuate the first film forming chamber 51 to the second film forming chamber 52 , and sputtering gas is supplied from the first gas supply machine 61 to the second gas supply machine 62 to the first film forming chamber 51 to the second film forming chamber 52 .

[0093] As the sputtering gas, for example, an inert gas such as Ar can be cited, and preferably a reactive gas mixed with an inert gas and a reactive gas such as oxygen can be cited. In the case of a reactive gas, the grain growth of the transparent conductive layer 3 can be controlled. The reactive gas is preferably a mixed gas of an inert gas and oxygen.

[0094] The ratio of the oxygen flow rate (mL / min) to the inert gas flow rate (mL / min) (oxygen flow rate / inert gas flow rate) is, for example, 0.0001 or more, preferably 0.001 or more, and, for example, less than 0.5, preferably 0.1 or less, more preferably less than 0.03, further preferably 0.02 or less, and particularly preferably 0.01 or less. When the above ratio is below the above upper limit, a transparent conductive layer 3 having appropriate resistance characteristics can be obtained.

[0095] The ratio of the oxygen flow rate (mL / min) to the inert gas flow rate (mL / min) in the sputtering gas supplied by the plurality of gas supply machines 61 to 62 (oxygen flow rate / inert gas flow rate) is the same or different. Preferably, the oxygen flow rate ratio of the reactive gas supplied by the plurality of gas supply machines 61 to 62 is different.

[0096] Specifically, the ratio R1 of the oxygen flow rate supplied by the first gas supplier 61 is higher than the ratio R2 of the oxygen flow rate supplied by the second gas supplier 62. Specifically, R1 / R2 is, for example, 1.5 or more, preferably 2 or more, more preferably 3 or more, further preferably 4 or more, and, for example, 20 or less.

[0097] If R1 is higher than R2, the oxygen content in the region on the second main surface 6 side of the transparent conductive layer 3 is high, which can promote the crystal growth in this region, and the crystal grains 4 grown from the first main surface 5 side and the crystal grains 4 grown from the second main surface 6 side are easily formed independently. Therefore, the first grain boundary 7 can be formed in the transparent conductive layer 3 more reliably.

[0098] Next, the take-up roller 39 is driven to unwind the substrate sheet 2 from the unwinding roller 38. The substrate sheet 2 moves relative to the first target 41 and the second target 42 while in contact with the surface of the film-forming roller 40. At this time, the substrate sheet 2 is cooled by contact with the surface of the film-forming roller 40. In the present application, the cooling temperature of the substrate sheet 2 is set to be substantially the same as the surface temperature of the film-forming roller 40.

[0099] The sputtering gas is ionized near each of the first target 41 and the second target 42 to generate an ionized gas. The ionized gas then collides with each of the first target 41 and the second target 42 to knock out the target materials of each of the first target 41 and the second target 42 and sequentially adhere to the base sheet 2.

[0100] The target material of the first target 41 is attached to the first main surface 21 of the substrate sheet 2, preferably to the first main surface 21 of the substrate sheet 2 cooled to the above temperature, and then the target material of the second target 42 is attached. That is, the target materials of the first target 41 to the second target 42 are sequentially deposited on the first main surface 21 of the substrate sheet 2.

[0101] Thus, the amorphous transparent conductive layer 28 is formed on the substrate first main surface 21. Thus, the amorphous transparent conductive sheet 29 including the substrate sheet 2 and the amorphous transparent conductive layer 28 is obtained.

[0102] It should be noted that the amorphous transparent conductive layer 28 is Figure 1 As shown in the enlarged view of B, the first region 71 formed of the target material of the first target 41 and the second region 72 formed of the target material of the second target 42 are included in order toward one side in the thickness direction.

[0103] It should be noted that Figure 1 In the enlarged view of B, in order to clearly show the relative positions of the first region 71 and the second region 72 adjacent to each other, the boundary between them is shown, but the boundary may not be clearly observed in the amorphous transparent conductive layer 28.

[0104] Next, the amorphous transparent conductive layer 28 is crystallized to form a crystalline transparent conductive layer 3 .

[0105] When the amorphous transparent conductive layer 28 is crystallized, for example, the amorphous transparent conductive layer 28 is heated.

[0106] The heating conditions are not particularly limited. The heating temperature is, for example, lower than 200° C., preferably lower than 180° C., more preferably lower than 170° C., and further preferably lower than 165° C. The heating time is, for example, more than 1 minute, preferably more than 3 minutes, more preferably more than 5 minutes, and, for example, less than 5 hours, preferably less than 3 hours, and more preferably less than 2 hours. In addition, the heating is, for example, performed in an air atmosphere.

[0107] As a result, the amorphous transparent conductive layer 28 is transformed into the transparent conductive layer 3 having a plurality of crystal grains 4 .

[0108] In this way, a transparent conductive sheet 1 including the base sheet 2 and the transparent conductive layer 3 is obtained.

[0109] The transparent conductive sheet 1 is formed into a suitable pattern, specifically, an electrode pattern, etc., by etching (specifically, wet etching using an etching solution). Thereafter, the transparent conductive sheet 1 having the patterned transparent conductive layer 3 is used for a touch sensor, an electromagnetic wave shield, a dimming element (a voltage-driven dimming element such as PDLC and SPD, a current-driven dimming element such as electrochromic (EC)), a photoelectric conversion element (a solar cell represented by an organic thin-film solar cell and a dye-sensitized solar cell, etc.), a heat ray control member (a near-infrared reflecting and / or absorbing member, a far-infrared reflecting and / or absorbing member), an antenna member (a light-transmitting antenna), an image display device, etc.

[0110] (Effects of one embodiment)

[0111] In the transparent conductive layer 3, if the etching liquid contacts the first main surface 5, the etching liquid easily penetrates into the first grain boundary 7 from the two end edges 23, so that the first crystal grains 31 separated by the first grain boundary 7 are easily etched. Specifically, both end edges 23 of the first grain boundary 7 separating the first crystal grains 31 face the first main surface 5, so if the etching liquid penetrates into the first grain boundary 7, the etching liquid from the two end edges 23 merges in the middle area 25. The first crystal grain 31 is not supported by the third crystal grain 33 facing the second main surface 6, for example, and is easily etched (including missing and falling off) from the transparent conductive layer 3. As a result, the etching rate of the transparent conductive layer 3 in the transparent conductive sheet 1 is high.

[0112] In the transparent conductive layer 3, when the etching liquid contacts the side surface 56, the etching liquid easily penetrates into the second grain boundary 8. Therefore, the second crystal grains 32 separated by the second grain boundary 8 are easily peeled off. As a result, the etching rate of the transparent conductive layer 3 in the transparent conductive sheet 1 is further increased.

[0113] (Variation Example)

[0114] In the following modifications, the same reference numerals are used for the same components and processes as those in the above-mentioned embodiment, and detailed description thereof is omitted. In addition, each modification can exert the same effects as those in the embodiment except for special description. Furthermore, the embodiment and its modifications can be appropriately combined.

[0115] In the above-mentioned sputtering device 30, the number of the plurality of targets 41-42, the number of the plurality of film forming chambers 51-52, and the number of the plurality of gas supply machines 61-62 are all 2, and may be, for example, 3 or more. For example, when the above-mentioned number is 3, in the step of forming the amorphous transparent conductive layer 28, the ratio of the oxygen flow rate supplied by the first gas supply machine 61 to the inert gas flow rate is made higher than the ratio of the oxygen flow rate supplied by the second gas supply machine 62 to the inert gas flow rate, and further the ratio of the oxygen flow rate supplied by the second gas supply machine 62 to the inert gas flow rate is made higher than the ratio of the oxygen flow rate supplied by the third gas supply machine 63 to the inert gas flow rate. When the above-mentioned number is plural, any adjacent gas supply machines make the ratio of the oxygen flow rate supplied by one gas supply machine to the inert gas flow rate higher than the ratio of the oxygen flow rate supplied by another gas supply machine adjacent to the downstream side of the one gas supply machine to the inert gas flow rate.

[0116] According to this method, the oxygen content in the region on the second main surface 6 side of the transparent conductive layer 3 is high, so that the crystal growth in this region can be promoted, and the crystal grains 4 grown from the first main surface 5 side and the crystal grains 4 grown from the second main surface 6 side are easily formed independently. Therefore, the first grain boundary 7 can be formed in the transparent conductive layer 3 more reliably.

[0117] In addition, if Figure 4 As shown, the transparent conductive layer 3 may include fourth crystal grains 34 separated by an intermediate region 25 between two third grain boundaries 9 whose other edges are open to the second main surface 6 and the first grain boundary 7 . The intermediate region 2 includes two second branch points 27 .

[0118] The fourth crystal grain 34 does not face the side surface 56 and the first main surface 5 , but faces only the second main surface 6 .

[0119] Furthermore, if Figure 5 As shown, the fifth crystal grain 57 which does not face the first main surface 5 , the second main surface 6 , and the side surface 55 may be included.

[0120] like Figure 6 As shown, the transparent conductive layer 3 does not have the third crystal grain 33 and the fourth crystal grain 34 (see Figure 4 ), that is, only the crystal grains 4 that do not face the second main surface 6, that is, only the first crystal grains 31. In this case, the intermediate region 25 does not include the first branch point 26 and the second branch point 27 (see Figure 4 ).

[0121] Preferably, as in one embodiment, the intermediate region 25 includes the second branch point 27, and the transparent conductive layer 3 includes the third grain boundary 9. Thus, if the etching solution penetrates from the second branch point 27 to the third grain boundary 9 and reaches the second main surface 6, the loss of the third crystal grain 33 can be promoted. Therefore, the etching speed can be further increased.

[0122] like Figure 7 As shown, the transparent conductive sheet 1 may further include a functional layer 19 located between the substrate sheet 2 and the transparent conductive layer 3. The functional layer 19 is in contact with the second main surface 6 and the first main surface 21 of the substrate. As the functional layer 19, for example, an anti-adhesion layer, an optical adjustment layer, a hard coating layer, a peeling functional layer, etc. may be cited. The functional layer 19 is a single layer or a multilayer. In the functional layer 19, as a constituent material, inorganic materials, organic materials, and composite materials of organic materials and inorganic materials can all be applied.

[0123] Although not shown, the transparent conductive layer 3 may be peeled off from the transparent conductive sheet 1 having a peeling functional layer as the functional layer 19 between the base sheet 2 and the transparent conductive layer 3. The peeled transparent conductive layer 3 may be used by, for example, transferring and bonding to other members constituting the touch sensor.

[0124] In the sputtering device 30, although not shown, a flat film-forming plate extending in the surface direction may be used instead of the film-forming roller 40. The plurality of targets 41 to 42 are arranged in parallel with the film-forming plate at intervals.

[0125] Example

[0126] Below, embodiment and comparative example are shown, and the present invention is described in more detail.It should be noted that the present invention is not limited by any embodiment and comparative example.In addition, the specific numerical values ​​such as the blending ratio (ratio), physical property value, parameter used in the following records can be replaced by the upper limit (defined as the numerical value of "below", "not enough") or the lower limit (defined as the numerical value of "above", "exceeding") of the blending ratio (ratio), physical property value, parameter corresponding to them recorded in the above-mentioned "specific embodiments".

[0127] Example 1

[0128] First, a PET film roll (manufactured by Mitsubishi Plastics Co., Ltd., with a thickness of 50 μm) was prepared. Next, an ultraviolet curable resin containing an acrylic resin was coated on the upper surface of the PET film roll and cured by ultraviolet irradiation to form a functional layer formed of a cured resin layer with a thickness of 2 μm. Thus, a substrate sheet 2 having a transparent substrate and a functional layer was obtained.

[0129] Thereafter, a transparent conductive layer 3 having a thickness of 155 nm was formed on the functional layer surface of the base sheet 2 by sputtering.

[0130] In detail, first, prepare a sputtering device 30 having a first target 41 formed of ITO with a tin oxide concentration of 10 mass % and a second target 42 formed of ITO with a tin oxide concentration of 3 mass %, and place the substrate sheet 2 on the discharge roller 38, film forming roller 40 and winding roller 39 of the sputtering device 30.

[0131] Next, the cooling device was driven to cool the surface temperature of the film-forming roller 40 to -8°C.

[0132] In addition, a plurality of pumps 50 are driven to make the first film forming chamber 51 to the second film forming chamber 52 each at 0.4 Pa and a vacuum (reduced pressure atmosphere), and reactive gases are supplied from the first gas supply machine 61 to the second gas supply machine 62 to the first film forming chamber 51 to the second film forming chamber 52 each at a flow ratio (oxygen flow rate / argon flow rate) recorded in Table 1.

[0133] In addition, the base sheet 2 is fed out from the feeding roll 38 by driving the winding roll 39 .

[0134] Then, sputtering is performed in each of the first film forming chamber 51 to the second film forming chamber 52 .

[0135] Thus, the amorphous transparent conductive layer 28 having the first region 71 to the second region 72 is formed on the substrate first main surface 21 of the substrate sheet 2. Thus, the amorphous transparent conductive sheet 29 including the substrate sheet 2 and the amorphous transparent conductive layer 28 is obtained.

[0136] Thereafter, the amorphous transparent conductive sheet 29 was heated at 165° C. for 120 minutes in air atmosphere to crystallize the transparent conductive layer 3 (amorphous transparent conductive layer 28 ). Thus, the transparent conductive sheet 1 including the base sheet 2 and the transparent conductive layer 3 was manufactured.

[0137] Comparative Example 1-Comparative Example 2

[0138] The same procedures as in Example 1 were carried out except that the film forming conditions and the thickness of the transparent conductive layer 3 were changed as described in Table 1.

[0139] <Evaluation>

[0140] The transparent conductive layer 3 of each example and comparative example was evaluated for the following items. Table 1 shows the results.

[0141] [Thickness of transparent conductive layer]

[0142] The thickness of the transparent conductive layer 3 was determined by cross-sectional observation using a transmission electron microscope (manufactured by Hitachi, Ltd., device name: “HF-2000”).

[0143] [Cross-sectional observation of grains]

[0144] After cross-section adjustment of the transparent conductive sheets 1 of Example 1 and Comparative Examples 1 and 2 was performed by FIB microsampling, the cross-sections of the transparent conductive layers 3 were observed by FE-TEM to observe the presence or absence of the second grain boundaries 8. The magnification was set so that any crystal grains 4 could be observed.

[0145] The apparatus and measurement conditions are as follows.

[0146] FIB device: Hitachi FB2200, accelerating voltage: 10kV

[0147] FE-TEM device: JEM-2800 manufactured by JEOL, accelerating voltage: 200 kV

[0148] As a result, in Example 1, the first crystal grains 31 were observed. In addition, the second crystal grains 32 , the third crystal grains 33 , and the fourth crystal grains 44 were also observed.

[0149] On the other hand, in Comparative Examples 1 and 2, the first crystal grains 31 were not observed, and only the fourth crystal grains 44 were observed.

[0150] [Maximum grain size of crystal grains on the first main surface]

[0151] The surface of the transparent conductive layer 3 is observed in the plane direction from the first main surface 5 side by surface FE-SEM, and the maximum grain size of the crystal grains 4 on the first main surface 5 is determined.

[0152] SEM equipment: Scanning electron microscope SU8020 manufactured by Hitachi High-Technologies

[0153] Accelerating voltage: 0.8 kV

[0154] [Etching rate of transparent conductive layer]

[0155] After the transparent conductive sheet 1 of the embodiment and each comparative example is immersed in hydrochloric acid with a concentration of 7 mass % and 35°C, it is washed with water and dried, and the inter-terminal resistance of 15 mm is measured by a tester (the measurement cycle of the tester is set to every 15 seconds). In this specification, the time when the inter-terminal resistance of 15 mm exceeds 50 kΩ or becomes insulating after immersion in hydrochloric acid, washing with water, and drying is regarded as the time when the etching of the transparent conductive layer 3 is completed, and this time is divided by the total thickness of the transparent conductive layer 3 to calculate the time required for etching 1 nm of the transparent conductive layer 3 (etching rate (seconds / nm)), and the evaluation is carried out according to the following criteria. Through this evaluation, the etching speed of the transparent conductive layer 3 can be determined without relying on the thickness of the transparent conductive layer 3.

[0156] ○: Etching time per unit thickness is less than 15 (sec / nm).

[0157] ×: The etching time per unit thickness is 15 or more (sec / nm).

[0158] [Table 1]

[0159]

[0160] It should be noted that the above invention is provided as an exemplary embodiment of the present invention, but this is merely an illustration and is not to be construed as limiting. Modifications of the present invention that are obvious to a person skilled in the art are included in the above claims.

[0161] Industrial Applicability

[0162] The transparent conductive layer is used, for example, for a transparent conductive sheet, a touch sensor, a light control element, a photoelectric conversion element, a heat ray control member, an antenna, an electromagnetic wave shielding member, and an image display device.

[0163] Description of Reference Numerals

[0164] 1 Transparent conductive sheet

[0165] 2. Substrate sheet

[0166] 3 Transparent conductive layer

[0167] 4 Grains

[0168] 5 Main side 1

[0169] 6 2nd main side

[0170] 8 Second grain boundary

[0171] 23 Edge

[0172] 25 Middle Area

[0173] 31 1st grain

[0174] 55 Side

[0175] 56 Side

Claims

1. A laminate, It is characterized in that The substrate sheet or the functional layer and the transparent conductive layer are sequentially provided toward one side in the thickness direction. The transparent conductive layer includes a first main surface exposed to the outside and a second main surface facing the first main surface in the thickness direction and in contact with one surface of the substrate sheet or the functional layer in the thickness direction. The transparent conductive layer is a single crystalline layer extending in a plane direction perpendicular to the thickness direction. The transparent conductive layer does not contain an amorphous region in the plane direction. The transparent conductive layer has: A first grain boundary in which both end edges in the cross-sectional view are open to the first main surface and an intermediate region between the two end edges does not contact the second main surface; first crystal grains separated by the first crystal boundary and facing only the first main surface; a second grain boundary that branches from the first grain boundary starting from a first branch point in the middle region of the first grain boundary and opens toward a side surface connecting an end edge of the first main surface and an end edge of the second main surface; a second crystal grain separated by the second crystal boundary and the first crystal boundary and facing only the first main surface and the side surface; a third grain boundary that branches from the first grain boundary starting from a second branch point in the middle region of the first grain boundary, has one end edge included in the middle region and has the other end edge open to the second main surface; and A third crystal grain separated by the middle region of the first crystal boundary, the second crystal boundary and the third crystal boundary and facing only the second main surface and the side surface; The substrate sheet is formed of at least one selected from the group consisting of polyester resin, (meth) acrylic resin, olefin resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, polystyrene resin and norbornene resin, The functional layer includes an organic material.

2. The laminate according to claim 1, It is characterized in that The material of the transparent conductive layer is tin-containing oxide.

3. A contact sensor, It is characterized in that A laminate according to claim 1 or 2.

4. A dimming element, It is characterized in that A laminate according to claim 1 or 2.

5. A photoelectric conversion element, It is characterized in that A laminate according to claim 1 or 2.

6. A heat ray control member, It is characterized in that A laminate according to claim 1 or 2.

7. An antenna, It is characterized in that A laminate according to claim 1 or 2.

8. An electromagnetic wave shielding member, It is characterized in that A laminate according to claim 1 or 2.

9. An image display device, It is characterized in that A laminate according to claim 1 or 2.

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