Electrically conductive substrate, electronic equipment and display equipment

Abstract

Electrically conductive substrate, comprising: a basic material; a base layer that is arranged on the base material and contains a catalyst; a trench-forming layer that is arranged on top of the base layer; and a conductive structural layer with metal plating, wherein a trench is formed with a lower surface to which the base layer is exposed, and a lateral surface which contains a surface of the trench-forming layer, the trench is filled with the electrically conductive structural layer, the base layer contains a mixed region formed from a surface of the base layer on the side of the conductive structural layer to its interior, and contains metal particles that contain a metal forming the conductive structural layer and enter the base layer, and wherein a gap is formed between at least part of a lateral surface of the conductive structural layer and the lateral surface of the trench.

Description

FIELD OF INVENTION

[0001] The present invention relates to an electrically conductive substrate, an electronic device and a display device. GENERAL STATE OF THE ART

[0002] There is a case where a transparent antenna provided with a conductive substrate having transparency and conductivity is mounted on a surface of a touch panel or a display. Currently, the conductive substrate is required to have high transparency and conductivity, as well as high flexibility, in accordance with the increase in size and diversification of touch panels and displays. For example, a related-art conductive substrate includes a conductive pattern layer formed of an ITO-containing resin, a metal foil, or a conductive nanowire, forming a fine pattern, on a transparent base material.

[0003] However, ITO, or conductive nanowire, is an expensive material. Furthermore, etching is commonly used as a method for forming a fine conductive pattern layer on a base material. However, the method using etching requires steps such as an exposure step, a development step, an etching step, and a stripping step, and the number of steps increases. Therefore, there is a limitation in producing a conductive substrate at low cost.

[0004] Japanese Unexamined Patent Publication No. 2016-164694 discloses a method in which a trench is formed on a transparent base material made of a resin, the entire surface of the transparent base material is filled with an electroconductive material such as copper according to a vapor deposition method or a sputtering method, the electroconductive material except that in the trench is removed by etching, and thus an electroconductive layer is formed, as a method for manufacturing the electroconductive substrate at a low cost. On the other hand, International Publication No. 2014 / 153895 discloses a method in which a trench is formed on a transparent base material made of a resin, and the trench is filled with an electroconductive material. CN 1 02 063 951 B describes, among other things, a substrate with metallization.US 2010 / 0 113 264 A1, US 2017 / 0 142 841 A1, and US 2014 / 0 218 325 A1 each describe a substrate. US 2016 / 0 027 973 A1 describes a light-emitting device. US 2008 / 0 136 019 A1 describes a photoelectric conversion device. US 2005 / 0 006 759 A1 describes a wafer structure. BRIEF PRESENTATION

[0005] In the current-conductive substrate of the related art including the current-conductive structural layer filling the trench, the current-conductive layer is peeled off and the current conductivity decreases at the time of repeated bending of the current-conductive substrate.

[0006] An object of the present invention is to provide an electrically conductive substrate in which an electrically conductive structural layer filling a trench is provided, and peeling of the electrically conductive structural layer and a decrease in electrical conductivity due to bending are suppressed, and an electronic device and a display device using the electrically conductive substrate. (Means of solving the problem)

[0007] According to one aspect of the present invention, there is provided an electroconductive substrate including: a base material; a ground layer disposed on a base material and containing a catalyst; a trench formation layer disposed on the ground layer; and an electroconductive structural layer with a metal plating. A trench having a bottom surface to which the ground layer is exposed and a lateral surface including a surface of the trench formation layer is formed. The trench is filled with the electroconductive structural layer. The ground layer includes a mixed region formed from a surface of the ground layer on the side of the electroconductive structural layer to the inside thereof, and contains metal particles containing a metal constituting the electroconductive structural layer and entering the ground layer.

[0008] It is preferable that a ratio of a thickness of the mixed layer to a thickness of the base layer is 0.1 to 0.9.

[0009] The width of the conductive structural layer can be 0.3 µm to 5.0 µm. The ratio of the thickness of the conductive structural layer to the width of the conductive structural layer can be 0.1 to 10.0.

[0010] It is preferred that the surface roughness Ra of a surface of the electrically conductive structural layer on a side opposite to the bottom surface of the trench is less than or equal to 100 nm.

[0011] Furthermore, a gap is formed between at least a part of a lateral surface of the electrically conductive structural layer and the lateral surface of the trench.

[0012] The electrically conductive structural layer may include a blackened surface that forms a surface of the electrically conductive structural layer, including a surface on a side opposite the bottom surface of the trench. The surface roughness Ra of the blackened surface may be 15 nm to 60 nm.

[0013] The electrically conductive substrate may further include a protective film covering at least a portion of a surface of the trench formation layer and the electrically conductive structural layer on a side opposite the base material. It is preferred that the refractive index of the protective film be greater than 1.0 and lower than the refractive index of the trench formation layer.

[0014] The electrically conductive structural layer can form a grid-like structure.

[0015] According to another aspect of the present invention, there is provided an electronic device including: the above-described electrically conductive substrate; and an electronic component mounted on the electrically conductive substrate.

[0016] According to yet another aspect of the present invention, there is provided a display device including: the above-described electrically conductive substrate; and a light-emitting element mounted on the electrically conductive substrate.

[0017] The electronic device or the display device may further include: a connecting portion disposed on the electrically conductive structural layer of the electrically conductive substrate, and the light-emitting element may be connected to the electrically conductive substrate through the connecting portion.

[0018] The electronic device or the display device may further include: an adhesive layer disposed on the electroconductive structural layer of the electroconductive substrate; an insulating layer disposed on the trench formation layer and the adhesive layer, covering a surface of the trench formation layer on a side opposite to the base layer, and including an opening portion to which a part of the adhesive layer is exposed; a UBM layer disposed on a surface of the adhesive layer exposed into the opening portion of the adhesive layer; and a connecting portion disposed on the UBM layer, and the light-emitting element may be connected to the electroconductive substrate through the connecting portion, the UBM layer, and the adhesive layer. BRIEF DESCRIPTION OF THE DRAWINGS Fig.1 is a schematic sectional view illustrating an electrically conductive substrate according to an embodiment. Fig. 2 is a partially enlarged view of the Fig. 1 shown electrically conductive substrate. Fig. 3A to 3E are sectional views showing a method of manufacturing the Fig. 1 shown electrically conductive substrate. Fig. 4A is a partially enlarged view illustrating the electrically conductive substrate according to an embodiment, and Fig. 4B is a partially enlarged view showing an example of an electroconductive substrate of the related art. Fig. 5 is a schematic sectional view illustrating the electrically conductive substrate according to an embodiment. Fig. 6A and Fig.6B are sectional views schematically illustrating an embodiment of a method for manufacturing a display device. Fig. 7A to 7C are sectional views schematically illustrating another embodiment of the method for manufacturing the display device. Fig. 8A to 8F are sectional views showing a modification example of the Fig. 7A to 7C. Fig. Fig. 9 is a plan view schematically showing a main part of the display device provided according to the Fig. 6A to 8F. Fig. 10A to 10D are process diagrams illustrating a method of manufacturing the electroconductive substrate of the related art. Fig. Figure 11 is a schematic view of a bending resistance testing machine. DETAILED DESCRIPTION

[0019] Embodiments of the present invention will be described below with appropriate reference to the drawings. The present invention is not limited to the following embodiments.

[0020] Fig. 1 is a schematic sectional view illustrating an electrically conductive substrate according to an embodiment. Fig. 1 includes a film-like base material 2, a ground layer 3 disposed on the base material 2, a trench formation layer 4 disposed on a surface of the ground layer 3 on a side opposite to the base material 2, and a ground-conductive structural layer 8. A trench 6 having a bottom surface 6a to which the ground layer 3 is exposed and lateral surfaces 6b and 6c including a surface of the trench formation layer 4 is formed, and the trench 6 is filled with the ground-conductive structural layer 8.

[0021] It is preferred that the base material 2 be a transparent base material, in particular a transparent resin film. The transparent resin film can be, for example, a film made of polyethylene terephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN), a cycloolefin polymer (COP), or a polyimide (PI). Alternatively, the base material 2 can be a glass substrate, a silicon wafer, or the like.

[0022] The thickness of the base material 2 may be greater than or equal to 10 µm, may be greater than or equal to 20 µm, or may be greater than or equal to 35 µm, or may be less than or equal to 500 µm, may be less than or equal to 200 µm, or may be less than or equal to 100 µm.

[0023] The base layer 3 contains a catalyst and a resin. The resin may be a curable resin, and examples thereof include an amino resin, a cyanate resin, an isocyanate resin, a polyimide resin, an epoxy resin, an oxetane resin, a polyester, an allyl resin, a phenolic resin, a benzoxazine resin, a xylene resin, a ketone resin, a furan resin, a COPNA resin, a silicone resin, a dicyclopentadiene resin, a benzocyclobutene resin, an episulfide resin, an ene-thiol resin, a polyazomethine resin, a polyvinyl benzyl ether compound, azenaphthylene, and an ultraviolet-curable resin having an unsaturated double bond or a functional group that causes a polymerization reaction by an ultraviolet ray, such as cyclic ether and vinyl ether, and the like.

[0024] It is preferable that the catalyst contained in the base layer 3 be an electroless plating catalyst. The electroless plating catalyst may be a metal selected from Pd, Cu, Ni, Co, Au, Ag, Pd, Rh, Pt, In, and Sn, with Pd being preferred. Only one type of metal may be used independently, or a combination of two or more types may be used as the catalyst. Generally, the catalyst is dispersed as catalyst particles in the resin.

[0025] The content of the catalyst in the base layer 3 may be greater than or equal to 3 mass%, may be greater than or equal to 4 mass%, or may be greater than or equal to 5 mass%, and may be less than or equal to 50 mass%, may be less than or equal to 40 mass%, or may be less than or equal to 25 mass%, based on the total amount of the base layer.

[0026] The thickness of the base layer 3 may be greater than or equal to 10 nm, may be greater than or equal to 20 nm, or may be greater than or equal to 30 nm, and may be less than or equal to 500 nm, may be less than or equal to 300 nm, or may be less than or equal to 150 nm.

[0027] It is preferred that the trench-forming layer 4 be a transparent resin layer. Furthermore, the trench-forming layer 4 may be a layer containing an uncured photocurable or thermosetting resin.Examples of the photocurable resin and the thermosetting resin constituting the trench formation layer 4 include an acrylic resin, an amino resin, a cyanate resin, an isocyanate resin, a polyimide resin, an epoxy resin, an oxetane resin, a polyester, an allyl resin, a phenol resin, a benzoxazine resin, a xylene resin, a ketone resin, a furan resin, a COPNA resin, a silicone resin, a dicyclopentadiene resin, a benzocyclobutene resin, an episulfide resin, an ene-thiol resin, a polyazomethine resin, a polyvinyl benzyl ether compound, azenaphthylene, and an ultraviolet ray-curable resin having an unsaturated double bond or a functional group that causes a polymerization reaction by an ultraviolet ray, such as cyclic ether and vinyl ether, and the like.

[0028] It is preferable that a refractive index (nd25) of the trench formation layer 4 be lower than a refractive index of the base layer 3 from the viewpoint of increasing the transparency of the electroconductive substrate, and it may, for example, be greater than or equal to 1.0, less than or equal to 1.7, less than or equal to 1.6, or less than or equal to 1.5. The refractive index can be measured by a reflection spectrography film thickness gauge.

[0029] The trench 6 includes the lower surface 6a, to which the base layer 3 is exposed, and the opposite lateral surfaces 6b and 6c, which include the surface of the trench formation layer 4 surrounding the lower surface 6a. The trench 6 extends on the base layer 3, so that a structure corresponding to the electrically conductive structural layer 8 is formed. As shown in Fig.As shown in Figure 1, the lateral surfaces 6b and 6c may be inclined relative to the bottom surface 6a such that the width of the trench 6 narrows from a surface 4a of the trench formation layer 4 on a side opposite the base layer 3 to the bottom surface 6, or the lateral surfaces 6b and 6c may be perpendicular to the bottom surface 6a. The lateral surfaces 6b and 6c may form a step.

[0030] Generally, the width and depth of the trench 6 are each set to substantially match the width and thickness of the electrically conductive structural layer 8. Here, the trench width indicates the maximum width in a direction perpendicular to a direction in which the trench extends. A ratio of the trench depth to the trench width may be identical to an aspect ratio of the electrically conductive structural layer described below.

[0031] The electrically conductive structural layer 8 may be a layer formed from a single metal plating or may be formed from multiple metal platings with different metals. For example, the electrically conductive structural layer 8 may include a seed layer, which is a metal plating formed on the base layer 3, and one or more upper metal plating layers, which are metal plating formed on a surface of the seed layer on a side opposite the base layer 3.

[0032] The metal plating as the electrically conductive structural layer 8, for example, contains at least one type of metal selected from copper, nickel, cobalt, palladium, silver, gold, platinum, and tin, and preferably contains copper. The electrically conductive structural layer 8 may further contain a non-metallic element such as phosphorus within a range where appropriate electrical conductivity is maintained.

[0033] In a case where the electroconductive structural layer 8 includes the seed layer and the upper metal plating layer, a metal forming the seed layer and a metal forming the upper metal plating layer may be identical to each other or may be different from each other. For example, the seed layer may contain nickel, and the upper metal plating layer may contain copper. The upper metal plating layer may include a copper plating layer formed on the seed layer and a top layer formed on the copper plating layer containing gold or palladium.

[0034] The electrically conductive structural layer 8 extends on the base layer 3, forming a structure corresponding to the trench 6. The thickness of the electrically conductive structural layer 8 may substantially coincide with the thickness of the trench formation layer 4, and the ratio of the thickness of the electrically conductive structural layer 8 to the thickness of the trench formation layer 4 may be within a range of 0.8 to 1.2.

[0035] The width of the electrically conductive structural layer 8 may be greater than or equal to 1 µm, greater than or equal to 10 µm, greater than or equal to 20 µm, and less than or equal to 90 µm, less than or equal to 70 µm, or less than or equal to 30 µm. Here, the width of the electrically conductive structural layer indicates the maximum width in a direction perpendicular to an extension direction of the electrically conductive structural layer.

[0036] The width of the electrically conductive structural layer 8 may be greater than or equal to 0.3 µm, may be greater than or equal to 0.5 µm, or may be greater than or equal to 1.0 µm, and may be less than or equal to 5.0 µm, may be less than or equal to 4.0 µm, or may be less than or equal to 3.0 µm, from the viewpoint of improving the transparency of the electrically conductive substrate.

[0037] The thickness of the electrically conductive structural layer 8 may be greater than or equal to 0.1 µm, greater than or equal to 1.0 µm, greater than or equal to 2.0 µm, and less than or equal to 10.0 µm, less than or equal to 5.0 µm, or less than or equal to 3.0 µm. The width and thickness of the electrically conductive structural layer 8 can be adjusted by changing the design of a mold 7 described below and by changing the width and thickness of the trench 6.

[0038] An aspect ratio of the electrically conductive structural layer 8 may be greater than or equal to 0.1, greater than or equal to 0.5, greater than or equal to 1.0, and less than or equal to 10.0, less than or equal to 7.0, or less than or equal to 4.0. By setting the aspect ratio of the electrically conductive structural layer 8 within the above-described range, it is possible to further increase the adhesion of the electrically conductive structural layer 8 to the base layer 3 and further increase the electrical conductivity. The aspect ratio of the electrically conductive structural layer indicates a ratio of the thickness of the electrically conductive structural layer to the width of the electrically conductive structural layer (thickness / width).

[0039] The electrically conductive structural layer 8, for example, may include a plurality of linear portions arranged to extend along a certain direction and may be formed into a grid shape.

[0040] Fig. 2 is an enlarged view of an area R in the sectional view of the Fig. 1 shown electrically conductive substrate 1. As in Fig.2, the base layer 3 includes a mixed region 20 formed from a surface of the base layer 3 on the side of the electrically conductive structural layer 8 (or an upper boundary M thereof) to the inside, and containing a plurality of metal particles 8R containing a metal that forms the electrically conductive structural layer 8 and enters the base layer 3. The mixed region 20 includes the metal particles 8R and a resin 31 and catalyst particles 32, which are main components of the base layer 3. Generally, the metal particles 8R include a metal plating that grows starting from the catalyst particles 32. For this reason, there are many cases where the catalyst particles 32 are integrated into the metal particles 8R. It is preferable that at least a part of the plurality of metal particles 8R be continuously connected from the electrically conductive structural layer 8 to the mixed region 20.It is possible to confirm that the mixing region 20 is formed, for example, by performing observation with a scanning electron microscope.

[0041] A thickness T of the mixed region 20 is preferably greater than or equal to 1 nm, is particularly preferably greater than or equal to 5 nm and is very particularly preferably greater than or equal to 10 nm and is preferably less than or equal to 500 nm, is particularly preferably less than or equal to 300 nm, is particularly preferably less than or equal to 200 nm and is very particularly preferably less than or equal to 100 nm, from the point of view of a further increase in the adhesion of the electrically conductive substrate 1.

[0042] Here, the thickness T of the mixed region 20 is defined as a distance from the upper boundary M on the electroconductive structural layer 8 side to a lower boundary N on the base material 2 side. Each of the upper boundary M and the lower boundary N is a sectional surface in a direction perpendicular to a thickness direction of the electroconductive substrate 1 (hereinafter referred to as a "horizontal plane"). The upper boundary M is positioned to be closest to the electroconductive structural layer side in a horizontal plane containing the resin 31 constituting the base layer 3. The lower boundary N is positioned to be closest to the base material 2 side in a horizontal plane containing the metal particles 8R.The upper limit M and the lower limit N can be determined by observing a sectional surface along the thickness direction of the electroconductive substrate 1A (hereinafter referred to as a "perpendicular plane") with a scanning electron microscope or the like. The thickness T of the mixed region can be obtained by observing multiple perpendicular planes, and the average value thereof can be regarded as the thickness T of the mixed region 20 of the electroconductive substrate 1. The mixed region is formed, and thus the electroconductive structural layer 8 can be effectively prevented from being peeled off from the base layer 3.

[0043] A ratio of the thickness T of the mixing region 20 to the thickness of the base layer 3 is preferably greater than or equal to 0.1, is particularly preferably greater than or equal to 0.2 and is particularly preferably greater than or equal to 0.3 and is preferably less than or equal to 0.9, is particularly preferably less than or equal to 0.6 and is very particularly preferably less than or equal to 0.5.

[0044] The surface roughness Ra of a surface 8a of the electrically conductive structural layer 8 on a side opposite to the lower surface 6a of the trench 6 is preferably less than or equal to 100 nm, more preferably less than or equal to 70 nm, and most preferably less than or equal to 30 nm. In a case where the surface roughness Ra of the surface 8a of the electrically conductive structural layer 8 is less than or equal to 100 nm, it is possible to reduce a loss in a skin effect. The lower limit of the surface roughness Ra is not particularly limited and is, for example, greater than or equal to 5 nm. A lateral surface of the electrically conductive structural layer 8 may have a surface roughness Ra within the above-described numerical range.

[0045] A gap may be formed between at least a part of the lateral surface of the electrically conductive structural layer 8 and the lateral surfaces 6b and / or 6c of the trench 6. Accordingly, it is possible to more effectively suppress damage to the electrically conductive structural layer 8 when the electrically conductive substrate 1A is bent. It is preferable that the gap be formed between the lateral surface of the electrically conductive structural layer 8 and both facing lateral surfaces 6b and 6c of the trench 6. The width of the gap may be greater than or equal to 1 nm, greater than or equal to 5 nm, greater than or equal to 10 nm, and less than or equal to 150 nm, less than or equal to 125 nm, or less than or equal to 100 nm.The width of the gap indicates the maximum value of a distance between the electrically conductive structural layer 8 and the trench 6 in a direction perpendicular to an extension direction of the electrically conductive structural layer 8. As described below, it is possible to easily form the gap between the electrically conductive structural layer 8 and the lateral surfaces 6b and 6c of the trench by growing the metal plating from the base layer 3 or the seed layer on the base layer 3.

[0046] The Fig. 3A to 3E are sectional views showing an embodiment of the method for manufacturing the Fig. 1 schematically illustrate the electrically conductive substrate 1A. In the method according to this embodiment, first, as shown in Fig. 3A, the catalyst-containing base layer 3 is formed on a main surface 2a of the film-like base material 2. A step of Fig.3A may be a step of preparing a laminated body including the base material 2 and the base layer 3 formed on the base material 2.

[0047] Then, as in Fig. 3B, the trench formation layer 4 is formed on a surface 3a of the base layer 3 on a side opposite to the base material 2. A step of Fig. 3B may be a step of preparing a laminated body 5A including the base material 2, the ground layer 3, and the trench formation layer 4 in this order.

[0048] Next, as in Fig. 3C and Fig.3D, the trench (a groove portion) 6 is formed according to a printing method using the mold 7 including a convex portion 7a. In this step, the mold 7 including the convex portion 7a having a predetermined shape is moved in a direction indicated by an arrow A and is thus pressed into the trench formation layer 4 ( Fig.3C). The mold 7 can be pressed until a tip end of the convex portion 7a reaches the base layer 3. In this state, in a case where the trench formation layer 4 is a layer containing an uncured photocurable or thermosetting resin, the trench formation layer 4 is cured. In a case where the trench formation layer 4 is a layer containing a photocurable resin, the trench formation layer 4 is cured by irradiation with light such as an ultraviolet ray. Thereafter, the mold 7 is removed, and thus the trench 6 having a shape on which the shape of the convex portion 7a of the mold 7 is reflected is formed ( Fig. 3D). A method for forming the trench 6 is not limited to the printing method, and for example, the trench 6 can be formed by a laser, dry etching, or photolithography.

[0049] As in Fig.As shown in Figure 3D, the trench 6 includes the bottom surface 6a to which the base layer 3 is exposed, and the opposite lateral surfaces 6b and 6c, which include the surface of the trench formation layer 4 surrounding the bottom surface 6a. The trench 6 extends on the base layer 3 such that a structure corresponding to the electrically conductive structural layer 8 is formed. To expose the base layer 3 to the bottom surface 6a of the trench 6, the trench formation layer 4 remaining on the base layer 3 in the trench 6 can be removed by etching, such as dry etching, after removing the mold 7.

[0050] The mold 7 can be formed of quartz, Ni, ultraviolet-curable liquid silicone rubber (PDMS), and the like. The shape of the convex portion 7a of the mold 7 is designed according to the shape of the groove 6 to be formed.

[0051] Next, as in Fig.3E, the electrically conductive structural layer 8 filling the trench 6 is formed. The electrically conductive structural layer 8 can be formed by an electroless plating method of growing the metal plating from the base layer 3. The laminated body 5A on which the trench 6 is formed is immersed in an electroless plating liquid containing a metal ion, and thus, the metal plating can be formed as the electrically conductive structural layer 8 starting from the catalyst contained in the base layer 3. The electrically conductive structural layer 8 filling the trench 6 is formed, and thus the electrically conductive substrate 1A can be obtained.

[0052] The electroless plating fluid contains the ion of the metal that forms the electrically conductive structural layer. The electroless plating fluid may also contain phosphorus, boron, iron, and the like.

[0053] The temperature of the electroless plating liquid at the time of immersing the laminated body 5A in the electroless plating liquid may be, for example, 40°C to 90°C. Furthermore, an immersion time of the electroless plating liquid varies according to the thickness of the electroconductive structural layer 8 and is, for example, 10 minutes to 30 minutes.

[0054] The electroconductive structural layer including the seed layer and the upper metal plating layer can be formed by a method that includes forming the seed layer on the base layer and forming the upper metal plating layer on the seed layer. The laminated body 5A in which the trench 6 is formed is immersed in the electroless plating liquid to form the seed layer, and thus, metal plating is formed starting from the catalyst contained in the base layer 3 as the seed layer. After that, the laminated body with the seed layer is immersed in the electroless plating liquid to form an electroconductive layer, and thus, the upper metal plating layer can be formed.The catalyst may be adsorbed in the seed layer before the upper metal plating layer is formed, and the upper metal plating layer may be formed starting from the catalyst adsorbed in the seed layer.

[0055] The thickness of the seed layer may be greater than or equal to 10 nm, may be greater than or equal to 30 nm, or may be greater than or equal to 50 nm, and may be less than or equal to 500 nm, may be less than or equal to 300 nm, or may be less than or equal to 100 nm.

[0056] The method according to this embodiment is excellent from the point of view of making it possible to easily form the electrically conductive structural layer with a constant width. Fig. 4A and Fig.4B are partially enlarged views illustrating an example of the electroconductive substrate having the electroconductive structural layer forming a lattice-like structure. In the case of the electroconductive substrate formed by the method according to this embodiment, as shown in Fig. 4A, the width of the electrically conductive structural layer 8 does not change greatly even in a region P near an intersection between two electrically conductive structural layers 8, and a constant width is easily maintained. In contrast, in a case of a related art method in which the electrically conductive structural layer is formed by etching, as shown in Fig.4B exemplifies a case where the width of the electrically conductive structural layer 8' increases in a region Q near an intersection between the two electrically conductive structural layers 8'. The fact that a variation in the width of the electrically conductive structural layer 8 is small and the fact that the width of the electrically conductive structural layer 8 does not increase in the region near the intersection are advantageous from the viewpoint of increasing a total light transmittance, and the fact that a variation in the width of the electrically conductive structural layer 8 is small is advantageous from the viewpoint of reducing a variation in the total light transmittance.

[0057] Fig. 5A is a schematic sectional view illustrating another embodiment of the electrically conductive substrate. The electrically conductive structural layer 8 of a Fig.The electrically conductive substrate 1B shown in FIG. 5B includes a blackened surface 25 forming a portion including the surface 8a on a side opposite the lower surface 6a of the trench 6 (hereinafter also referred to as an upper surface 8a of the electrically conductive structural layer), and lateral surfaces 8b and 8c within the surfaces. Regarding the blackened surface 25, "blackened" indicates that a surface is processed such that a normal reflectivity with respect to light incident on the surface of the blackened surface 25 is reduced.

[0058] The blackened surface 25 may be a black metal plating formed by using a black metal plating liquid, or may be a black metal plating formed by a Raydent (registered trademark) treatment. Generally, the blackened surface 25 is arranged as the electrically conductive layer forming part of the electrically conductive structural layer 8.

[0059] Examples of black metal plating formed by the black metal plating liquid include black nickel plating, black chromium plating, black zinc chromate plating, black rhodium plating, black ruthenium plating, tin-nickel-copper alloy plating, tin-nickel alloy plating, and substituted palladium plating.

[0060] The blackened surface 25 can be formed by a process of roughening the surface of the electroconductive structural layer 8. In this case, the surface roughness Ra of the blackened surface 25 is preferably greater than or equal to 15 nm, more preferably greater than or equal to 20 nm, more preferably greater than or equal to 30 nm, more preferably less than or equal to 60 nm, more preferably less than or equal to 55 nm, and more preferably less than or equal to 50 nm. Ra can be measured by a scanning probe microscope (SPM). The roughening is performed by a process of roughening the surface of the electroconductive structural layer 8 according to an acid treatment or the like, a process of forming the electroconductive structural layer 8 so that the surface of the electroconductive structural layer 8 is roughened, or the like.

[0061] The thickness of the blackened surface 25 (a film of black metal plating) may be greater than or equal to 10 nm, may be greater than or equal to 30 nm, or may be greater than or equal to 50 nm, and may be less than or equal to 150 nm, may be less than or equal to 125 nm, or may be less than or equal to 100 nm.

[0062] The blackened surface 25, which forms the surface 8a on the side opposite to the bottom surface 6a of the trench 6, for example, can be formed by forming the black metal plating covering the surface 8a after the electrically conductive structural layer 8 is formed. In a case where the gap is formed between the lateral surfaces 8b and 8c of the electrically conductive structural layer 8 and the lateral surface of the trench 6, there are many cases where the black metal plating, which covers not only the surface 8a of the electrically conductive structural layer 8 on the side opposite to the bottom surface 6a of the trench 6, but also the lateral surfaces 8b and 8c of the electrically conductive structural layer 8, is formed by dipping it in the plating liquid for black metal plating.

[0063] The blackened surface 25 may be configured as a layer forming a surface of the electrically conductive structural layer 8 on the lower surface 6a side of the trench 6. For example, a blackened surface forming the surface of the electrically conductive structural layer 8 on the lower surface 6a side of the trench 6 may be formed on the base layer 3 by using black metal plating (e.g., black nickel plating) as the seed layer after the trench 6 is formed.

[0064] The electroconductive substrate may further include a protective film covering at least a portion of the surface of the trench formation layer 4 and the electroconductive structural layer 8 on a side opposite to the base material 2. The protective film may include, for example, a resin and a filler. Examples of the resin of the protective film include an amino resin, an isocyanate resin, a silicone resin, an acrylic resin, a polycarbonate resin, a fluororesin, and an ultraviolet-curable resin having an unsaturated double bond or a functional group that causes a polymerization reaction by an ultraviolet ray, such as cyclic ether or vinyl ether, and the like. Examples of the filler of the protective film include silicon oxide, zirconium oxide, titanium oxide, aluminum oxide, magnesium fluoride-zinc oxide, antimony oxide, phosphorus-doped tin oxide, antimony-doped tin oxide, tin-doped indium oxide, Ag nanocolloid, and the like.For example, a resin composition for forming the protective film is applied to the surface of the trench formation layer 4 and the electrically conductive structural layer 8 on the side opposite the base material 2, and the coated film is dried and / or cured as necessary, thus forming the protective film. In a case where the gap is formed between the electrically conductive structural layer 8 and the lateral surfaces 6b and 6c of the trench 6, the protective film can fill the gap.

[0065] The thickness of the protective film may be greater than or equal to 10 nm, may be greater than or equal to 50 nm, or may be greater than or equal to 100 nm, and may be less than or equal to 5000 nm, may be less than or equal to 3000 nm, or may be less than or equal to 1000 nm.

[0066] The refractive index of the protective film may be greater than or equal to 1.0, or greater than or equal to 1.3, and less than or equal to 1.6, or less than or equal to 1.5 from the perspective of transparency of the electroconductive substrate. It is preferable that the refractive index of the protective film be lower than the refractive index of the trench formation layer 4. The refractive index of the protective film can be adjusted, for example, by increasing or decreasing the filler content. [Display setup]

[0067] A light-emitting element is mounted on the above-described electrically conductive substrate, and thus it is possible to manufacture a display device including the electrically conductive substrate and the light-emitting element. In the above-described electrically conductive substrate, the electrically conductive structural layer is prevented from peeling off from the base layer, and thus the display device including such an electrically conductive substrate is manufactured to be as thin as cloth or paper and can be used as a flexible display device (display) that can be folded or rolled. Such a flexible display device can be reduced in size and weight, and its storability and designability can be improved.

[0068] The Fig. 6A and Fig.6B are sectional views schematically illustrating an embodiment of a method for manufacturing the display device. In this method, first, as shown in Fig.6A, a light-emitting element 40 and the electrically conductive substrate 1A are prepared. The light-emitting element 40 includes a light-emitting unit 41, a positive electrode 42 arranged on a main surface 41a of the light-emitting unit 41, and a negative electrode 43 arranged on the main surface 41a at a distance from the positive electrode 42. Hereinafter, the positive electrode 42 and the negative electrode 43 may be collectively referred to as electrodes 42 and 43. The light-emitting element 40 may be an element capable of emitting red light, green light, or blue light. The light-emitting element 40 may be, for example, a light-emitting diode (LED). In this embodiment, the electrically conductive structural layer 8 of the electrically conductive substrate 1A includes a plurality of linear portions 81 and 82 extending along a certain direction.

[0069] The shape of the light-emitting element 40 (the shape of the light-emitting unit 41) is not particularly limited and may, for example, be an approximately quadrilateral shape (a rectangular shape, a square shape, and the like). The dimension of the light-emitting element 40 can be appropriately set, and in a case where the light-emitting element 40 has a quadrangular shape, it is preferable that the width of the light-emitting element 40 is less than or equal to 100 μm, less than or equal to 80 μm, less than or equal to 60 μm, less than or equal to 30 μm, or less than or equal to 20 μm from the viewpoint of further improving the resolution of the display device. In this case, it is preferable that the length of the light-emitting element 40 is less than or equal to 50 µm, less than or equal to 40 µm, less than or equal to 30 µm, less than or equal to 20 µm, or less than or equal to 10 µm.The width of the light-emitting element 40 may be greater than or equal to 5 µm, may be greater than or equal to 10 µm, or may be greater than or equal to 20 µm. In this case, the length of the light-emitting element 40 may be greater than or equal to 5 µm, or may be greater than or equal to 10 µm. When the light-emitting element 40 is mounted on the electroconductive substrate 1A in a step described below, the width of the light-emitting element 40 is set as a direction corresponding to the width of the electroconductive structural layer 8. The length of the light-emitting element 40 is set as a direction along the extension direction of the electroconductive structural layer 8.

[0070] Next, as in Fig.6B, the light-emitting element 40 is mounted on the electrically conductive substrate 1A. Such a step involves connecting the electrodes 42 and 43 of the light-emitting element 40 to the electrically conductive structural layer 8 of the electrically conductive substrate 1A. At this time, the positive electrode 42 and the negative electrode 43 of the light-emitting element 40 are respectively connected to two adjacent linear portions 81 and 82 of the electrically conductive structural layer 8, and thus the light-emitting element 40 is electrically connected to the electrically conductive structural layer 8. Accordingly, it is possible to obtain a display device 50A in which the light-emitting element 40 is mounted on the electrically conductive substrate 1A.

[0071] The Fig.7A to 7C are sectional views schematically illustrating another embodiment of the method for manufacturing the display device. Such a method is different from the method of the above-described embodiment in that the step of mounting the light-emitting element 40 on the electrically conductive substrate 1A includes forming a connecting portion on the electrically conductive pattern layer 8 of the electrically conductive substrate 1A and connecting the light-emitting element 40 to the electrically conductive pattern layer 8 through the connecting portion.

[0072] In this procedure, first, as in Fig. 7A and Fig.7B, a connecting portion 44 is formed on the electrically conductive structural layer 8 of the electrically conductive substrate 1A. The connecting portion 44 may be formed to contact at least a portion of the upper surface 8A of the electrically conductive structural layer 8.

[0073] The connecting portion 44 may be formed on the upper surface 8A of the electroconductive structural layer 8 by using a small ball formed of a solder alloy or may be formed by printing a paste formed of a solder alloy. The connecting portion 44 may be formed according to an electroless plating method of growing metal plating from the electroconductive structural layer 8. In a case where the connecting portion 44 is formed according to the electroless plating method, the connecting portion 44 may contain tin, silver, copper, bismuth, indium, and the like, or may contain an alloy of any two or more materials as a forming material. In this embodiment, it is preferable that the connecting portion 44 be formed by a small ball or a paste formed of a solder alloy.

[0074] The dimension of the connecting portion 44 can be suitably adjusted so that the electrodes 42 and 43 of the light-emitting element 40 can be in contact with the connecting portion 44. For example, as shown in Fig. 7B, the connecting portion 44 may be formed such that its width is identical to the width of the electrically conductive structural layer 8. The connecting portion 44 may be formed such that its width is smaller than the width of the electrically conductive structural layer 8, and a part of the upper surface 8a of the electrically conductive structural layer 8 may be exposed.

[0075] Next, as in Fig.7C, the electrodes 42 and 43 of the light-emitting element 40 are in contact with a surface 44a of the connecting portion 44 on a side opposite to a surface in contact with the electroconductive structural layer 8, and thus the light-emitting element 40 is connected to the electroconductive substrate 1A through the connecting portion 44. At this time, the positive electrode 42 and the negative electrode 43 of the light-emitting element 40 are brought into contact with two adjacent connecting portions 44, and thus the light-emitting element 40 is electrically connected to the electroconductive substrate 1A. Accordingly, it is possible to obtain a display device 50B in which the light-emitting element 40 is mounted on the electroconductive substrate 1A.

[0076] The Fig.8A to 8F are sectional views schematically illustrating a modification example of the method for manufacturing the display device, including connecting the light-emitting element 40 to the electroconductive substrate 1A through the connecting portion 44. According to this modification example, it is possible to more appropriately and easily mount the light-emitting element 40 to the electroconductive substrate 1A, and thus, this modification example is particularly preferably used in a case where a smaller light-emitting element 40 is mounted to the electroconductive substrate 1A.

[0077] In this procedure, first, as in Fig. 8A and Fig.8B, an adhesive layer 45 is formed on the electrically conductive structural layer 8 of the electrically conductive substrate 1A. The adhesive layer 45 may be formed in at least a part of the upper surface 8a of the electrically conductive structural layer 8. The adhesive layer 45 is formed, and thus, when an insulating layer described below is formed on the trench formation layer 4 and the electrically conductive structural layer 8, it is possible to prevent the insulating layer from being peeled off.

[0078] It is preferable that the adhesion layer 45 be formed according to an electroless plating method of growing metal plating from the electroconductive structural layer 8. It is preferable that the adhesion layer 45 contain at least one kind selected from nickel and a nickel alloy as a forming material from the viewpoint of improving adhesion with a UBM layer described below and the connecting portion 44 and the light-emitting element 40 disposed on the UBM layer. It is particularly preferable that the adhesion layer 45 contain at least one kind selected from the group consisting of zinc and phosphorus, in addition to at least one kind selected from the group consisting of nickel and a nickel alloy.

[0079] It is preferable that a surface 45a of the adhesive layer 45 be roughened on a side opposite a surface in contact with the electrically conductive structural layer 8 (hereinafter also referred to as an upper surface 45a of the adhesive layer 45). The upper surface 45a of the adhesive layer 45 is roughened, and thus the insulating layer adheres more easily to the upper surface 45a of the adhesive layer 45 according to an anchoring effect.

[0080] A method of roughening the upper surface 45a of the adhesive layer 45 is performed by a method of roughening the upper surface 45a of the adhesive layer 45 after plating according to an acid treatment and the like, a method of forming the adhesive layer 45 after the plating liquid is adjusted so that a surface of the adhesive layer 45 is roughened, or the like.

[0081] The surface roughness Ra of the adhesive layer 45 is preferably greater than or equal to 0.1 µm, more preferably greater than or equal to 0.3 µm, and most preferably greater than or equal to 0.5 µm from the viewpoint of further improving adhesion to the insulating layer described below. Ra is preferably less than or equal to 1 µm, more preferably less than or equal to 0.8 µm, and most preferably less than or equal to 0.7 µm from the viewpoint of ensuring the strength of the display device. Ra can be measured by the same measurement method as that described in the blackened surface.

[0082] The thickness of the adhesive layer 45 is preferably greater than or equal to 0.1 µm, more preferably greater than or equal to 0.5 µm, and particularly preferably greater than or equal to 1.0 µm from the viewpoint of obtaining a suitable surface roughness Ra. The thickness of the adhesive layer 45 may be less than or equal to 2.0 µm, may be less than or equal to 1.8 µm, or may be less than or equal to 1.5 µm.

[0083] Then, as in Fig. 8C, an insulating layer 46 is formed covering the surface 4a of the trench formation layer 4 on the side opposite to the base layer 3 and including an opening portion to which the upper surface 45a of the adhesive layer 45 is exposed. It is preferable that the insulating layer 46 be formed to cover the surface 4a of the trench formation layer 4 and a part of the adhesive layer 45 (for example, an end portion of the upper surface 45a of the adhesive layer 45).

[0084] The insulating layer 46 is formed from a material with insulating properties. The material with insulating properties can be an inorganic material or a resin. Examples of the inorganic material include a compound containing silicon, such as SiO2 and SiN. Examples of the resin include an epoxy resin, polyimide, and the like.

[0085] As in Fig.As shown in Fig. 8D, a UBM layer (a sub-barrier metal layer) 47 is formed on the upper surface 45a of the adhesion layer 45, which is exposed in the opening portion of the insulating layer 46. It is preferable that the UBM layer 47 be formed according to an electroless plating method of growing the metal plating from the adhesion layer 45. The UBM layer 47 may contain at least one kind of metal selected from the group consisting of nickel, cobalt, iron, and copper. The UBM layer 47 may further contain a non-metal element such as phosphorus. It is preferable that the UBM layer 47 contains nickel or contains nickel and phosphorus.

[0086] As in Fig.As shown in FIG. 8E, the connecting portion 44 is formed on a surface 47a of the UBM layer 47 on a side opposite to the electroconductive substrate 1A. A forming material and a forming method of the connecting portion 44 may be identical to the forming material and forming method of the above-described embodiment, and in this modification example, it is preferable that the connecting portion 44 be formed according to an electroless plating method of growing metal plating from the UBM layer 47 from the viewpoint of mounting a smaller light-emitting element 40. It is preferable that the connecting portion 44 contains tin or an alloy thereof as a forming material. A part of the connecting portion 44 to be formed on the UBM layer 47 may be in contact with a surface of the insulating layer 46.

[0087] As in Fig.8F, the light-emitting element 40 is connected to the formed connecting portion 44. Accordingly, it is possible to obtain a display device 50C in which the light-emitting element 40 is connected to the electrically conductive structural layer 8 of the electrically conductive substrate 1A through the connecting portion 44, the UBM layer 47, and the adhesive layer 45. That is, the light-emitting element 40 is mounted on the electrically conductive substrate 1A according to the step of forming the adhesive layer 45, the insulating layer 46, the UBM layer 47, and the connecting portion 44, and connecting the light-emitting element 40 to the connecting portion 44.

[0088] Fig. Fig. 9 is a plan view schematically illustrating a main part of a display device 50 (50A to 50C) constructed according to the Fig. 6A to 8F. In the case of the Fig.In the display device 50 shown in FIG. 9, a plurality of light-emitting elements 40 (40a, 40b, and 40c) are arranged along an extension direction L of two adjacent linear portions while spanning two adjacent linear portions 81 and 82 of the electroconductive structural layer 8 of the electroconductive substrate 1A. The light-emitting element 40 may be formed of a light-emitting element 40a including a red light-emitting unit, a light-emitting element 40b including a green light-emitting unit, and a light-emitting element 40c including a blue light-emitting unit, and such light-emitting elements 40a, 40b, and 40c may be arranged in an arbitrary arrangement.For example, a distance D1 in a width direction of the electrically conductive structural layer 8 may be less than or equal to 400 µm, and a distance D2 in the extension direction L of the electrically conductive structural layer 8 may be less than or equal to 200 µm, as a distance between the adjacent light-emitting elements 40 (40a, 40b and 40c).

[0089] In the method of manufacturing the display device 50 described above, a further step of disposing a sealing portion covering an exposed portion of the light-emitting element 40 may be provided. The sealing portion may be formed from, for example, a resin such as silicone resin, epoxy resin, and olefin resin.

[0090] It is also possible to mount the light-emitting element according to another embodiment on the electrically conductive substrate 1B according to the same method as that of the first embodiment and manufacture the display device. In this case, the light-emitting element 40 can be mounted by connecting it directly or through the connecting portion 44 to the blackened surface 25 of the electrically conductive substrate 1B. [Electronic device]

[0091] In another embodiment, an electronic component other than the light-emitting element can be mounted on the electrically conductive substrate manufactured by the above-described method. Examples of the electronic component other than the light-emitting element include a passive component such as a capacitor, an inductor, a thermistor, a semiconductor element, a connector, and the like. Accordingly, it is possible to manufacture an electronic device including an electronic component on the electrically conductive substrate manufactured by the above-described method, in addition to the display device. [Examples]

[0092] In the following, the present invention will be specifically described by examples, but the present invention is not limited to the examples. [Example 1]

[0093] A catalyst-containing resin for forming a base layer containing 20 mass% Pd particles and an isocyanate resin were prepared. The catalyst-containing resin was coated onto a PET film (100 μm thick), which is a transparent base material, using a precoater. The coated film was heated to 80°C and cured, thus forming a base layer (100 nm thick). Subsequently, an ultraviolet-curable transparent acrylic-based oligomer was coated onto the base layer using a precoater, thus forming a trench layer (2 μm thick).

[0094] A Ni mold was fabricated, in which a lattice-like structure was formed and a convex portion with a width of 1 µm was provided. The mold was pressed against the trench formation layer, and a tip end of the convex portion of the mold reached the base layer. In this state, the trench formation layer was hardened by irradiating it with an ultraviolet ray. Accordingly, a trench was formed, including a bottom surface to which the base layer was exposed. The trench width was 1 µm, the trench depth was 2 µm, and the distance between adjacent trenches was 100 µm.

[0095] A laminated body containing the trench formation layer in which the trench was formed was immersed in an alkaline degreasing liquid containing a surfactant for 5 minutes. Afterward, the laminated body was removed from the degreasing liquid and washed with pure water. After washing, the laminated body was immersed in an electroless plating liquid containing nickel sulfate and sodium hypophosphite for 3 minutes. A metal plating layer (100 nm thick) composed of Ni and P was grown as a seed layer from the base layer exposed to the bottom surface of the trench. The laminated body was removed from the electroless plating liquid and washed with pure water.Next, the laminated body in which the seed layer was formed was immersed in an aqueous solution containing Pd for 5 minutes and then washed with pure water, and Pd particles as a catalyst were adsorbed in the seed layer. After that, the laminated body was immersed in an electroless plating liquid containing copper sulfate and formalin for 5 minutes, and thus, a Cu plating (an upper metal plating layer) filling the trench was grown on the seed layer. The laminated body was removed from the electroless plating liquid, washed with pure water, and dried at 80°C for 3 minutes, forming a grid-like structure. Thus, an electroconductive substrate containing an electroconductive structural layer formed from the seed layer and the Cu plating was obtained.In the electrically conductive substrate, a width W of the electrically conductive structural layer was 1 µm, the thickness of the electrically conductive structural layer was 2 µm, and an aspect ratio (thickness / width) of the electrically conductive structural layer was 2. A distance S between adjacent electrically conductive structural layers was 200 µm. In the obtained electrically conductive substrate, a cut surface of the electrically conductive structural layer was cut out using a cross-section polisher, and it was confirmed that a gap was formed between a lateral surface of the trench and a lateral surface of the electrically conductive structural layer, according to observation using a scanning electron microscope. [Examples 2 to 5]

[0096] An electrically conductive substrate was manufactured by the same method as that in Example 1, except that the width W of the electrically conductive structural layer (the width of the trench) and the thickness of the electrically conductive structural layer (the depth of the trench) were changed to the values ​​shown in Table 1. [Examples 6 to 9]

[0097] An electrically conductive substrate was prepared by the same method as that in Example 1, by changing the thickness of the electrically conductive structural layer (the depth of the trench) to the values ​​shown in Table 1. [Comparison example 1]

[0098] An electrically conductive substrate without the base layer was prepared according to a manufacturing method of Fig.10A to 10D. First, an ultraviolet-curable transparent acrylic-based oligomer was coated on the same PET film (the base material 2) as that of Examples, and the trench-forming layer 4 (a thickness of 2 μm) was formed. A mold in which a lattice-like structure was formed and a convex portion with a width of 1 μm was provided was pressed against the trench-forming layer 4, and a tip end of the convex portion reached the base material 2. In such a state, the trench-forming layer 4 was cured by irradiating it with an ultraviolet ray, and thus a laminated body 5C in which the trench 6 was formed with the bottom surface to which the base material 2 was exposed was obtained ( Fig.10A). Next, a Cu seed layer 11 covering the entire surface of the trench formation layer 4 and the entire bottom surface 6a was formed by a sputtering method ( Fig. 10B). Thereafter, the laminated body 5C was immersed in an electroless plating liquid containing copper sulfate and formalin, and thus the Cu plating was grown from the seed layer 11, and a Cu plating layer 8A, which filled the trench 6 and covered the entire trench formation layer 4, was formed ( Fig. 10C). Thereafter, a portion of the Cu plating layer 8A other than a portion filling the interior of the trench 6 was removed by etching ( Fig.10D), and thus, an electrically conductive substrate 1C according to Comparative Example 1 having the electrically conductive structural layer 8 was manufactured. In the obtained electrically conductive substrate, the cut surface of the electrically conductive structural layer 8 was cut out using a cross-section polisher, and it was confirmed that the electrically conductive structural layer 8 adhered to the lateral surfaces 6b and 6c of the trench 6 and no gap was formed therebetween, according to observation using a scanning electron microscope.

[0099] In each of the electrically conductive substrates, the surface roughness Ra of a surface of the electrically conductive structural layer on a side opposite the bottom surface of the trench was measured within a field of view of 1 μm using a scanning probe microscope. Furthermore, the cut surface (the perpendicular plane) of each of the electrically conductive substrates was observed, and it was confirmed that a mixed region was formed in which particles containing nickel, a metal constituting the seed layer of the electrically conductive structural layer, entered the base layer. In the mixed region, a plurality of metal particles were continuously bonded to the electrically conductive structural layer. The thickness of the mixed region was measured based on the observation of the perpendicular plane. In the electrically conductive substrate of Comparative Example 1, the mixed region was not formed. <biegetest>

[0100] A sample of each electrically conductive substrate with a length of 150 mm and a width of 50 mm was prepared. The sample was subjected to a bending test according to JISC5016 using a Fig. 11. That is, the electrically conductive substrate 1 was adjusted to conform to a circular peripheral surface (radius of curvature d: 5 mm) of a bent portion 14, while an end portion 12 of the electrically conductive substrate 1 was fixed to a fixing portion 13, and thus the electrically conductive substrate 1 was arranged to be bent. Thereafter, an end portion 15 on a side opposite to the end portion 12 was reciprocated along a direction shown by an arrow B. A moving distance by which the end portion 15 was reciprocated was set to 30 mm, and a reciprocating cycle was set to 150 times / minute, and thus the end portion 15 was repeatedly reciprocated back and forth for 1 minute. <Evaluierung der Stromleitfähigkeit (Messung des Oberflächenwiderstands)>

[0101] The surface resistance of each of the conductive substrates before and after the bending test was measured using a non-contact resistance meter EC-80P (manufactured by Napson Corporation). The measurement was performed in an area of ​​ϕ20 mm on the surface of the conductive substrate. The electrical conductivity was evaluated in the following four grades based on the measurement results. A grade of A indicates that the electrical conductivity is extremely excellent. Rank A: The surface resistance is less than 5 Ω / square Rank B: The surface resistance is greater than or equal to 5 Ω / square and less than 10 Ω / square Rank C: The surface resistance is greater than or equal to 10 Ω / square and less than 15 Ω / square Rank D: The surface resistance is greater than or equal to 15 Ω / square <Evaluierung der Haftung>

[0102] A cut surface of the electrically conductive substrate after the bending test was observed with a scanning electron microscope, and the presence or absence of peeling of the electrically conductive structural layer from the base layer or base material was confirmed. <Evaluierung der Transparenz.

[0103] The total light transmittance of the electroconductive substrate was measured according to JISK7136 using an NDH5000 turbidity meter (manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD.). The transparency of the transparent electroconductive substrate was evaluated according to the measurement results in the following three grades. A grade of A indicates that the transparency is extremely excellent. Rank A: Total light transmittance of the electrically conductive substrate / total light transmittance of the base material x 100 = greater than or equal to 98% Rank B: Total light transmittance of the electrically conductive substrate / total light transmittance of the base material x 100 = greater than or equal to 96% and less than 98% Rank C: Total light transmittance of the electrically conductive substrate / total light transmittance of the base material x 100 = less than 96%

[0104] As shown in Table 1, the electrically conductive substrates of Examples 1 to 9 were found to prevent the electrically conductive structural layer from peeling off after the bending test and to maintain excellent electrical conductivity. [Examples 10 to 12]

[0105] Several electroconductive substrates were prepared by the same method as in Example 1. These electroconductive substrates were immersed in a Pd-containing aqueous solution for 5 minutes and then washed with pure water, thus adsorbing Pd particles as the catalyst into the surface of the electroconductive structural layer. Thereafter, the electroconductive substrate was immersed in an electroless plating liquid for black Ni plating for 3 minutes, thus forming a black Ni plating film as the uppermost layer of the electroconductive structural layer on a side opposite the bottom surface of the trench and on the lateral surface side of the trench. Each of the electroconductive substrates taken out of the electroless plating liquid was washed with pure water.Furthermore, the black Ni plating film was subjected to acid treatment, and the surface roughness Ra of the black Ni plating film was adjusted to 15 nm (Example 10), 58 nm (Example 11), or 65 nm (Example 12) by adjusting the acid treatment time. The surface roughness Ra and the thickness of the mixed region were measured using the same method as in Examples 1 to 9. <Evaluierung der Stromleitfähigkeit und Messung der Transmittanz>

[0106] For the electroconductive substrates of Examples 10 to 12 and Example 1, the transparency and electrical conductivity were evaluated using the same method as the one described above. As shown in Table 2, it was found that when Ra was 15 nm to 60 nm, the transparency and electrical conductivity were particularly excellent.

[00109] [Table 2] Electrically conductive structural layer (trench) Evaluation result W / S (µm) Thickness (µm) Thickness of the mixed area (nm) Ra (nm) transparency Electrical conductivity Example 1 1 / 200 2 38 8 B B Example 10 1 / 200 2 38 15 A B Example 11 1 / 200 2 38 58 A B Example 12 1 / 200 2 38 65 A C

[00110] [Examples 13 to 15]

[0107] Several electroconductive substrates were prepared by the same method as in Example 1. A curable resin composition for forming a protective film was applied to the surface of the trench formation layer and the electroconductive structural layer of such electroconductive substrates with a doctor blade. The coated film was dried and then cured by irradiating it with an ultraviolet ray, thus forming a protective film (a thickness of 100 nm) covering the trench formation layer and the electroconductive structural layer. The curable resin composition for forming the protective film used here contains a filler (silicon oxide) and a fluororesin. A refractive index of the protective film was adjusted to the values ​​shown in Table 3 by changing the content of the filler. The thickness of the mixed region was measured by the same method as in Examples 1 to 9.

[00111] <Evaluierung der Transparenz>

[0108] For the electroconductive substrates of Examples 13 to 15 and Example 1, the transparency of the electroconductive substrate was measured using the same method as the method described above. The results are shown in Table 3. As shown in Table 3, it was found that in a case where the refractive index of the protective film was above the refractive index of air of 1.0 and below the refractive index of the trench formation layer, the transparency was particularly excellent.

[0109] According to the present invention, it is possible to manufacture the electrically conductive substrate in which the electrically conductive structural layer filling the trench is provided and the peeling of the electrically conductive structural layer and a decrease in electrical conductivity due to bending are suppressed, and the electronic device using the electrically conductive substrate.

[0110] Furthermore, the present invention is also capable of providing the display device in which the peeling of the conductive structural layer in the conductive substrate is suppressed. Recently, a display device (e.g., an LED display) including a light-emitting element such as a light-emitting diode (LED) has been developed. In a liquid crystal display (LCD), the backlight is controlled by transmissive liquid crystals, but in the LED display, a pixel is formed using a light-emitting diode, which is a natural light-emitting element. Accordingly, the LED display has characteristics such as high brightness, long lifetime, and a wide viewing angle.

[0111] In the display device including the light-emitting element, it is preferable to reduce the size of the light-emitting element itself to improve resolution. However, in a case where the size of the light-emitting element decreases, it is necessary to form a fine electroconductive structural layer, and thus the electroconductive structural layer tends to peel off easily, and it is difficult to ensure electroconductivity. According to the present invention, it is possible to easily manufacture the display device in which, even in a case where the size of the light-emitting element decreases, the electroconductive structural layer of the electroconductive substrate is hardly peeled off, and the adhesion between the light-emitting element and the electroconductive substrate is excellent.

[0112] 1A, 1B: electrically conductive substrate, 2: base material, 3: ground layer, 4: trench formation layer, 6: trench, 6a: bottom surface of the trench, 6b, 6c: lateral surface of the trench, 8: electrically conductive structural layer, 8a: surface of the electrically conductive structural layer on a side opposite to the bottom surface of the trench, 8b, 8c: lateral surface of the electrically conductive structural layer, 8R: metal particles, 20: mixed region, 25: blackened surface, 31: resin, 32: catalyst particles, T: thickness of the mixed region, 40: light-emitting element, 44: connecting portion, 45: adhesion layer, 46: insulating layer, 47: UBM layer, 50: display device.< / biegetest>

Claims

[1] Electrically conductive substrate comprising: a base material; a base layer disposed on the base material and containing a catalyst; a trenching layer disposed on the base layer; and an electrically conductive structural layer with metal plating, wherein a trench is formed having a lower surface to which the base layer is exposed and a lateral surface containing a surface of the trench forming layer, the trench is filled with the electrically conductive structural layer, the base layer contains a mixed region formed from a surface of the base layer on the side of the electrically conductive structural layer to the inside thereof and containing metal particles containing a metal forming the electrically conductive structural layer and entering the base layer, and wherein a gap is formed between at least a part of a lateral surface of the electrically conductive structural layer and the lateral surface of the trench. [2] The electroconductive substrate according to claim 1, wherein a ratio of a thickness of the mixed region to a thickness of the base layer is 0.1 to 0.

9. [3] The electrically conductive substrate according to claim 1 or 2, wherein a width of the electrically conductive structural layer is 0.3 µm to 5.0 µm and a ratio of the thickness of the electrically conductive structural layer to the width of the electrically conductive structural layer is 0.1 to 10.

0. [4] The electrically conductive substrate according to any one of claims 1 to 3, wherein a surface roughness Ra of a surface of the electrically conductive structural layer on a side opposite to the bottom surface of the trench is less than or equal to 100 nm. [5] The electrically conductive substrate according to any one of claims 1 to 4, wherein the electrically conductive structural layer includes a blackened surface forming a surface of the electrically conductive structural layer including a surface on a side opposite to the lower surface of the trench, and the surface roughness Ra of the blackened surface is 15 nm to 60 nm. [6] An electrically conductive substrate according to any one of claims 1 to 5, further comprising: a protective film covering at least a part of a surface of the trench formation layer and the electrically conductive structure layer on a side opposite to the base material, wherein a refractive index of the protective film is above 1.0 and smaller than a refractive index of the trench formation layer. [7] An electrically conductive substrate according to any one of claims 1 to 6, wherein the electrically conductive structural layer forms a lattice-like structure. [8] Electronic device comprising: the electrically conductive substrate according to any one of claims 1 to 7; and an electronic component mounted on the electrically conductive substrate. [9] Electronic device according to claim 8, further comprising: a connecting portion arranged on the electrically conductive structural layer of the electrically conductive substrate, wherein the electronic component is connected to the electrically conductive substrate by the connecting portion. [10] Electronic device according to claim 8, further comprising: an adhesive layer disposed on the electrically conductive structural layer of the electrically conductive substrate; an insulating layer disposed on the trench formation layer and the adhesion layer, covering a surface of the trench formation layer on a side opposite to the base layer, and including an opening portion to which a part of the adhesion layer is exposed; a UBM layer disposed on a surface of the adhesive layer exposed into the opening portion of the adhesive layer; and a connecting section arranged on the UBM layer, wherein the electronic component is connected to the electrically conductive substrate by the connecting portion, the UBM layer and the adhesive layer. [11] Display device comprising: the electrically conductive substrate according to any one of claims 1 to 7; and a light-emitting element mounted on the electrically conductive substrate. [12] A display device according to claim 11, further comprising: a connecting portion arranged on the electrically conductive structural layer of the electrically conductive substrate, wherein the light-emitting element is connected to the electrically conductive substrate through the connecting portion. [13] A display device according to claim 11, further comprising: an adhesive layer disposed on the electrically conductive structural layer of the electrically conductive substrate; an insulating layer disposed on the trench formation layer and the adhesion layer, covering a surface of the trench formation layer on a side opposite to the base layer, and including an opening portion to which a part of the adhesion layer is exposed; a UBM layer disposed on a surface of the adhesive layer exposed into the opening portion of the adhesive layer; and a connecting section arranged on the UBM layer, wherein the light-emitting element is connected to the electrically conductive substrate through the connecting portion, the UBM layer and the adhesive layer.

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