TW201735058A - Transparent conductive film, method for manufacturing transparent conductive film, metal mold, and method for manufacturing metal mold - Google Patents

Abstract

A transparent conductive film 10, 20 is provided with: a transparent film 11, 21; and a linear conductive part 13, 23 extending on the transparent film 11, 21. The conductive part 13, 23 constitutes a random network structure, the width of the conductive part 13, 23 is within a range of 200 to 3000 nm, and the height of the conductive part 13, 23 is larger by 0.5 times than the width W of the conductive part 13, 23. In the transparent conductive film 10, 20, pattern visibility and moire are not generated, and the resistance of the film is low.

Description

Transparent conductive film, method for producing transparent conductive film, metal mold, and method for manufacturing metal mold

The present invention relates to a transparent conductive film, a method for producing the same, and a metal mold for producing a transparent conductive film and a method for producing the same.

Transparent electrodes have become an essential element in display devices such as thin televisions, mobile phones, smart phones, and input boards, touch panels, solar cells, electroluminescent elements, electromagnetic masks, and functional glass. As a conductive material for the transparent electrode of these electronic devices, indium tin oxide (hereinafter abbreviated as ITO) is becoming the mainstream.

However, since indium, which is a raw material of ITO, is a rare metal, and therefore there is uneasiness in the future supply. Further, since the steps for performing the sputtering of the ITO film are low in productivity and low in cost, an alternative material for ITO is required.

As an alternative material to the ITO film, for example, Patent Document 1 proposes a conductive nanowire mesh and a method of manufacturing the same. This has the advantage that the nanowires constituting the conductive nanowire mesh are not recognized because the average width is 1.5 μm or less (there is no "pattern appearance"). Moreover, since the mesh structure is irregular, water ripple is not substantially generated.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2014/129504

In addition to the above problems, it is expected that the alternative material of the ITO film is further reduced in resistance. Further, it is also expected to manufacture a large-area transparent conductive film. Accordingly, it is an object of the present invention to provide a low-resistance transparent conductive film which does not generate both "pattern display" and water ripple. Further, a further object of the present invention is to provide a method for producing a large-area transparent conductive film which can be easily and inexpensively manufactured, a metal mold used in the production method, and a method for producing the same.

According to a first aspect of the present invention, a transparent conductive film comprising: a transparent film and a linear conductive portion extending over the transparent film; and the conductive portion forming a random mesh structure, the width of the conductive portion In the range of 200 to 3000 nm, the height of the conductive portion is 0.5 times or more the width of the conductive portion.

In the transparent conductive film, the transparent film has a concave portion, and the conductive portion may be made of a conductive material filled in the concave portion.

In the transparent conductive film, the conductive portion may protrude from the surface of the transparent film.

In the above transparent conductive film, the random network structure may be formed in the arrangement A plurality of specific regions of the surface of the transparent film.

The transparent conductive film further includes a lead wiring formed on the transparent film, and the lead wiring may be electrically connected to the random mesh structure formed in the plurality of specific regions.

According to a second aspect of the present invention, there is provided a metal mold having a concave-convex pattern, wherein the convex portion of the concave-convex pattern constitutes a random mesh structure, and a height of the convex portion is 0.5 times a width of the convex portion. the above.

According to a third aspect of the present invention, a method of manufacturing a metal mold for manufacturing a metal mold having a convex portion having a random network structure, comprising: dispersing a nanofiber on a substrate, and the substrate Forming a random network structure composed of the above-mentioned nanofibers; forming the concave-convex pattern of the random network structure on the substrate by using the nanofiber as a mask and etching the substrate; and fabricating the substrate a resin mold of the first transfer pattern obtained by inverting the concave-convex pattern; and the resin pattern is removed by electroforming a metal layer on the first transfer pattern of the resin mold, thereby forming the resin mold A metal mold of a second transfer pattern obtained by inverting a transfer pattern.

In the method for producing a metal mold described above, the random network structure composed of the nanofibers may be formed only in a specific region of the substrate.

The method for producing a metal mold described above may be included in the mold for forming a lead wiring.

According to a fourth aspect of the present invention, a method for producing a transparent conductive film, comprising: manufacturing a metal mold by a manufacturing method of a third aspect; and forming a random mesh on the surface of the transparent film by using the metal mold The conductive portion of the structure.

In the method for producing a transparent conductive film, the forming the conductive portion may include: forming a transparent film having a third transfer pattern obtained by inverting the second transfer pattern of the metal mold; and the transparent film The concave portion of the third transfer pattern is filled with a conductive material.

In the method for producing a transparent conductive film, the forming the conductive portion may include: applying a conductive material to a convex portion of the second transfer pattern of the metal mold; and applying the conductive material to the above The metal mold is pressed against the transparent film, and the conductive material is adhered to the transparent film.

In the transparent conductive film of the present invention, since the height of the linear conductive portion constituting the random network structure is relatively large with respect to the width, prevention of pattern development and reduction in resistance can be simultaneously achieved. Further, since the conductive portion constitutes a random mesh structure, no water ripple is generated even if two transparent conductive films are stacked on the display element. Further, according to the manufacturing method of the present invention, it is simple A large-area transparent conductive film is produced at low cost. Therefore, the transparent conductive film of the present invention can be preferably used for various devices such as a touch panel, an electronic paper, and a thin film solar cell.

10, 10a, 10b, 20, 20a‧‧‧transparent conductive film

11, 11a, 21, 21a‧‧‧ transparent film

12‧‧‧Transparent resin layer

13, 13a, 23, 23a‧‧‧Electrical Department

15, 15a, 25, 25a‧‧‧ random mesh structure

17, 17a, 27, 27a‧‧‧ lead wiring

24‧‧·coating film

35, 35a‧‧‧ concave pattern

40‧‧‧Resin mould

45‧‧‧1st transfer pattern

50‧‧‧Metal mold

51, 51a‧‧‧ substrate

53, 53a‧‧‧Nano fiber

55‧‧‧2nd transfer pattern

57‧‧‧ resin layer

59‧‧‧metal layer

65‧‧‧3rd transfer pattern

71, 73‧‧‧Support substrate

91‧‧‧ mask

97‧‧‧ Leading wiring pattern

Fig. 1(a) is a view conceptually showing a cross-sectional structure of a transparent conductive film of a first embodiment, and Fig. 1(b) is a view conceptually showing a cross-sectional structure of a transparent conductive film of a second embodiment.

Fig. 2 is a view conceptually showing a planar structure of a transparent conductive film according to the first embodiment and the second embodiment.

Fig. 3 (a) is a view conceptually showing a cross-sectional structure of a transparent conductive film according to a third embodiment, and Fig. 3 (b) is a view conceptually showing a cross-sectional structure of a transparent conductive film according to a fourth embodiment.

4(a) and 4(b) are diagrams conceptually showing the planar structure of the transparent conductive film of the third embodiment and the fourth embodiment.

Fig. 5 is a flow chart showing a method of producing a transparent conductive film.

6(a) to 6(f) are diagrams conceptually showing steps A1 to A4 of the method for producing a transparent conductive film.

7(a) to 7(c) are diagrams conceptually showing the conductive portion forming step A5 of the method for producing a transparent conductive film according to the first embodiment.

(a) to (c) of FIG. 8 are diagrams conceptually showing the conductive portion forming step A5 of the method for producing a transparent conductive film of the second embodiment.

9(a) to 9(d) conceptually show the transparency of the third embodiment and the fourth embodiment. The NF patterning step of the method for producing a conductive film and the pattern forming step for the lead wiring.

(a) to (d) of FIG. 10 are diagrams conceptually showing a modification of the substrate etching step and the patterning step for forming the lead wiring in the method for manufacturing the transparent conductive film of the third embodiment.

Fig. 11A is a cross-sectional SEM photograph of the transparent conductive film of Example 1.

Fig. 11B is a cross-sectional SEM photograph of the transparent conductive film of Example 2.

11C is a cross-sectional SEM photograph of the transparent conductive film of Comparative Example 1.

Hereinafter, embodiments of the transparent conductive film of the present invention and a method for producing the same will be described with reference to the drawings.

[Transparent Conductive Film (First Embodiment)]

As shown in FIG. 1(a), the transparent conductive film 10 of the present embodiment includes a transparent film 11 and a linear conductive portion 13 extending on the transparent film 11. The transparent film 11 has a concave portion 11c, and the conductive portion 13 is made of a conductive material filled in the concave portion 11c.

<transparent film>

The transparent film 11 is composed of a transparent supporting substrate 73 and a transparent resin layer 12 formed on the transparent supporting substrate 73. A concave portion 11c is formed in the transparent resin layer 12.

As the transparent resin layer 12, a resin such as photocuring, heat curing, moisture curing, or chemical curing (two-liquid mixing) can be used. Specific examples thereof include epoxy, acrylic, methacrylic, vinyl ether, oxycyclobutane, urethane, melamine, urea, polyester, and polyolefin. Various resins such as a phenol type, a crosslinked liquid crystal type, a fluorine type, an anthrone type, a polyamidamide type, a monomer, an oligomer, and a polymer. The thickness of the transparent resin layer 12 can be Within the range of 0.5~500μm. When the thickness is less than the lower limit, the depth of the concave portion 11c formed in the transparent resin layer 12 may be insufficient. When the thickness exceeds the above upper limit, the influence of the volume change of the resin generated during curing may increase.

As the transparent supporting substrate 73, a known film substrate that allows visible light to pass through can be used. For example, a substrate composed of a transparent inorganic material such as glass can be used; and polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyarylate, etc.) ), (meth)acrylic resin (such as polymethyl methacrylate), polycarbonate, polyvinyl chloride, styrene resin (such as ABS resin), cellulose resin (such as triacetin), A substrate composed of a resin such as a polyimide-based resin (polyimine-imine resin or polyamidamine resin) or a cycloolefin polymer. The transparent support substrate 73 may be a resin film from the viewpoint of flexibility. The thickness of the transparent supporting substrate 73 is preferably from 1 to 500 μm from the viewpoint of optical characteristics.

<Electrical part>

The conductive portion 13 is formed to bury the recess 11c of the transparent film 11. There is no step difference between the upper surface 13s of the conductive portion 13 and the surface 11s of the transparent film 11, and both may lie in the same plane. That is, the depth of the concave portion 11c and the height H of the conductive portion 13 may be equal. Alternatively, the depth of the recess 11c and the height H of the conductive portion 13 may not be equal. In addition, "the surface 11s of the transparent film 11" means the surface 11s other than the recessed part 11c of the transparent film 11.

The conductive portion 13 has a linear (conductor-like) shape, and as shown in FIG. 2, the random mesh structure 15 is formed in a plan view. In the present case, "random mesh structure" means a structure in which at least one nanowire is combined in such a manner as to form a random network (mesh). In the case where the random network structure is composed of a plurality of nanowires, each nanowire has a junction or intersection with at least one of the other nanowires, whereby the plurality of nanowires are substantially uninterrupted continuous. The random mesh structure does not include: It is composed of a n-angle, a circle, an ellipse, or the like such as a triangle, a quadrangle, a hexagon, or the like, or a combination of a specific pattern or a specific pattern based on the combination of the patterns, and exhibits a regular regular mesh (mesh) structure. Originally, the random mesh structure may be an irregular structure as a whole, and a mesh having a regular shape which is accidentally generated by a part is not excluded. Such a random mesh structure 15 has no anisotropy and has a mesh-like irregularity, so that no water ripple is generated. Further, since the density of the mesh (mesh) can be easily controlled as described later, it is possible to simultaneously achieve good light transmittance and conductivity in accordance with specific applications. The linear conductive portion 13 constituting the random mesh structure 15 may be composed of one continuous wire or a plurality of independent wires. In summary, the wires are desirably of sufficient length to create a plurality of contacts and/or intersections with themselves and/or other wires.

The width W of the linear conductive portion 13 may be in the range of 200 to 3000 nm, or may be in the range of 200 to 900 nm. When the width W exceeds 3,000 nm, the conductive portion 13 may be recognized and "pattern appearance" may occur. When the width W is less than 200 nm, the conductivity of the conductive portion 13 may become insufficient.

The coverage of the conductive portion 13 with respect to the transparent film 11 may be in the range of 1% to 15%. When the coverage ratio is less than 1%, the conductivity of the transparent conductive film 10 may be insufficient. When the coverage ratio exceeds 15%, the transparency (penetration ratio) of the transparent conductive film 10 may become insufficient.

Further, the height H of the conductive portion 13 is 0.5 times or more, preferably 0.5 to 4 times the width W of the conductive portion 13. That is, the cross-sectional shape of the surface perpendicular to the extending direction of the conductive portion 13 is preferably in the range of 1:2 to 4:1. The height H of the conductive portion 13 of the present embodiment is 0.5 or more times the width W of the conductive portion 13, and the conductive portion 13 is formed even when the width W of the conductive portion 13 is 3000 nm or less in order to prevent "pattern appearance". Can also have sufficient guidance Electrical. Thereby, the transparent conductive film 10 can simultaneously achieve a good appearance and high conductivity without pattern development. With such a configuration, the transparent conductive film 10 can have a low sheet resistance in the range of 1 to 80 Ω/sq, preferably 1 to 50 Ω/sq. Further, the height H of the conductive portion 13 is not more than four times the width W of the conductive portion 13, whereby the pattern appearing when the transparent conductive film 10 is obliquely observed can be prevented.

Examples of the material of the conductive portion 13 include metals such as iron, cobalt, nickel, copper, zinc, chromium, molybdenum, niobium, tantalum, palladium, silver, cadmium, lanthanum, cerium, platinum, gold, and aluminum, and the like. Alloy, ITO, indium gallium zinc oxide (IGZO), titanium, cobalt oxide, zinc oxide, vanadium oxide, indium oxide, aluminum oxide, nickel oxide, tin oxide, antimony oxide, antimony oxide, vanadium oxide, zirconium oxide, etc. A metal compound exemplified as an oxide or a metal nitride such as titanium nitride, zirconium nitride or aluminum nitride. From the viewpoint of conductivity, copper, silver, aluminum, and indium tin oxide are preferable, and from the viewpoint of flexibility, a metal or an alloy such as silver, aluminum, or copper is preferable.

[Transparent Conductive Film (Second Embodiment)]

As shown in FIG. 1(b), the transparent conductive film 20 of the present embodiment includes a transparent film 21 and a linear conductive portion 23 extending over the transparent film 21. The conductive portion 23 is placed on the surface 21s of the transparent film 21.

<transparent film>

As the transparent film 21, the same as the transparent support substrate 73 in the first embodiment can be used.

<Electrical part>

The conductive portion 23 is placed on the surface 21s of the transparent film 21 and protrudes with respect to the surface 21s of the transparent film 21. Similarly to the conductive portion 13 of the first embodiment, the conductive portion 23 constitutes a random mesh structure 25 as shown in FIG. 2 in plan view. Moreover, the width W, the height H, and the height H of the conductive portion 23 The ratio to the width W, the material, and the coverage ratio are also the same as those of the conductive portion 13 of the first embodiment.

[Transparent Conductive Film (3rd Embodiment)]

As shown in Fig. 3 (a), the transparent conductive film 10a of the present embodiment includes a transparent film 11a and a linear conductive portion 13a extending over the transparent film 11a, similarly to the transparent conductive film 10 of the first embodiment. The lead wiring 17 is provided on the transparent film 11a.

The transparent film 11a is composed of a transparent supporting substrate 73a and a transparent resin layer 12a formed on the transparent supporting substrate 73a. As the transparent supporting substrate 73a, the transparent resin layer 12a, and the conductive portion 13a, the same materials as those of the transparent supporting substrate 73, the transparent resin layer 12, and the conductive portion 13 of the first embodiment can be used. Further, in the plan view, the conductive portion 13a constitutes the random mesh structure 15a in the same manner as the conductive portion 13 of the first embodiment, and the width W, the height H, the ratio of the height H to the width W of the conductive portion 13a, and the material are also the first The conductive portions 13 of the embodiment are the same.

As shown in FIGS. 4(a) and 4(b), the random mesh structure 15a is formed only in a plurality of specific regions 11p arranged on the transparent film 11a. Further, in FIGS. 4(a) and 4(b), the random mesh structure 15a is not explicitly illustrated, but the random mesh structure 15a formed in the specific region 11p and the random mesh structure shown in FIG. The structure of 15 is the same. The plurality of specific regions 11p may be arranged in a lattice shape. The specific regions 11p may be arranged at a pitch of 200 to 5000 μm, and each of the specific regions 11p may have any shape such as a circular shape, a quadrangular shape, or a polygonal shape. Further, the specific regions 11p adjacent to each other in a specific direction of FIG. 4(a) are connected to each other and electrically connected. The specific region 11p adjacent to the direction perpendicular to the above direction is spaced apart by a distance of 0.5 to 500 μm, and can be electrically separated.

As shown in FIG. 3(a), there is no step difference between the upper surface 17s of the lead wiring 17, the upper surface 13as of the conductive portion 13a, and the surface 11as of the transparent film 11a, which may all be in the same plane, or may not be in the same plane. Inside.

As shown in FIGS. 4(a) and 4(b), the lead wires 17 are electrically connected to the random mesh structure 15a formed in the plurality of specific regions 11p. The lead wires 17 may have a line width in the range of 5 to 1000 μm and may have a resistance in the range of 0.01 to 50 Ω. As the material of the lead wiring 17, the same material as the material exemplified as the conductive portion 13 can be used.

In the transparent conductive film 10a _x shown in FIG. 4(a), the specific region 11p adjacent to the lateral direction of the paper surface is electrically connected, and the respective columns of the electrically connected specific regions 11p are electrically connected to the lead wires 17, respectively. . In the transparent conductive film 10a _y shown in FIG. 4(b), the specific regions 11p adjacent to each other in the longitudinal direction of the paper surface are electrically connected, and the respective rows of the electrically connected specific regions 11p are electrically connected to the lead wires 17, respectively. The transparent conductive film 10a _x and the transparent conductive film 10a _y can be used as a touch panel.

[Transparent Conductive Film (Fourth Embodiment)]

As shown in Fig. 3 (b), the transparent conductive film 20a of the present embodiment includes a transparent film 21a and a linear conductive portion 23a extending over the transparent film 21a, similarly to the transparent conductive film 20 of the second embodiment. Further, the transparent wiring 21a is provided with the lead wiring 27. The conductive portion 23a and the lead wiring 27 are placed on the surface 21s of the transparent film 21a, and are protruded from the surface 21as of the transparent film 21a.

As the transparent film 21a and the conductive portion 23a, the same materials as those of the transparent film 21 and the conductive portion 23 of the second embodiment can be used. Further, in plan view, the conductive portion 23a constitutes the random mesh structure 25a in the same manner as the conductive portion 23 of the first embodiment, and the width W, the height H, the ratio of the height H to the width W of the conductive portion 23a, and the material are also the second The conductive portion 23 of the embodiment is the same.

4(a) and 4(b), the random network structure 25a of the transparent conductive films 20a _x and 20a _{y and} the random network structure of the transparent conductive films 10a _x and 10a _y of the third embodiment Similarly to 15a, only a plurality of specific regions 21p arranged on the transparent film 21a are formed. The arrangement of the plurality of specific regions 21p can be the same as the arrangement of the plurality of specific regions 11p of the transparent conductive films 10a _x and 10a _y of the third embodiment.

As shown in FIGS. 4(a) and 4(b), the lead wiring 27 is electrically connected to the random mesh structure 25a formed in the plurality of specific regions 21p in the same manner as the lead wiring 17 of the third embodiment. The lead wiring 27 can have the same line width and electric resistance as the lead wiring 17 of the third embodiment. As the material of the lead wiring 27, the same material as that of the lead wiring 17 of the third embodiment can be used. Further, similarly to the transparent conductive films 10a _x and 10a _{y of} the third embodiment, the transparent conductive film 20a _x shown in Fig. 4 (a) is overlapped with the transparent conductive film 20a _y shown in Fig. 4 (b). Can be used as a touch panel.

[Method for Producing Transparent Conductive Film of First Embodiment]

A method of manufacturing the transparent conductive film 10 of the first embodiment will be described. As shown in FIG. 5, the method for producing a transparent conductive film mainly includes a step A1 of dispersing a nanofiber (NF) on a substrate, and a step A2 of forming a concave-convex pattern by using NF as a mask and etching the substrate. The step A3 of the resin mold of the first transfer pattern in which the uneven pattern of the substrate is reversed, the step A4 of forming the metal mold using the resin mold, and the step A5 of forming the conductive portion on the transparent film using the metal mold.

<scatter of NF>

As shown in Fig. 6(a), NF53 is spread on the substrate 51 to form a random network structure composed of NF53 (step A1 of Fig. 5).

As the substrate 51, a tantalum substrate or the like can be used. In the case of using a germanium substrate, an SiOx film can be formed by thermal oxidation equal to the surface of the substrate. The SiOx film functions as a hard mask in the subsequent etching step. Moreover, in order to improve the adhesion between the substrate 51 and the NF 53, the substrate 51 can be Surface treatment is carried out, an easy-to-adhere layer is set, or energy from the outside such as heat or light is applied. Further, in order to fill the surface protrusion of the substrate 51, a smoothing layer or the like may be provided.

Any type of nanofiber can be used as long as it can form a random network structure in a plan view. Examples of the nanofiber that can be used include polyesters such as polyethylene terephthalate or polyethylene naphthalate; liquid crystalline aromatic polyesters; liquid crystalline wholly aromatic polyesters; and polycarbonates; Polyacrylate such as polymethyl acrylate or polyethyl acrylate; polymethacrylate such as polymethyl methacrylate or polyethyl methacrylate or polyhydroxyethyl methacrylate; polypropylene decylamine, polymethyl Polyolefins such as acrylamide, polyacrylonitrile, polyethylene or polypropylene; cycloolefin resins, polyvinyl chloride, polystyrene, polylactic acid, aliphatic polyamines, wholly aromatic polyamines, polyimines, Polyetheretherketone, polypentene, polyfluorene, polythioether, poly-p-phenylene benzoate Conductive polymers such as azole, polyacetylene or polypyrrole or polythiophene; high molecular weights such as polyurethane, epoxy resin, phenol resin, cellulose acetate, nitrocellulose, hydroxypropyl cellulose, chitin or polyglucosamine Molecules; hydrophilic polymers such as polyethylene oxide, polyvinyl alcohol, polyvinylpyrrolidone; polypeptides such as polybenzyl glutamate; fluoropolymers such as polyvinylidene fluoride, polyoxyalkylene or poly A ruthenium-containing polymer such as a semi-oxane or a polydecane; a phosphorus-containing polymer such as polyphosphazene, an acrylonitrile-butadiene-styrene copolymer or a copolymer or mixture of such substances. Here, the copolymer may be any copolymer containing a random copolymer, an alternating copolymer, a block copolymer, or a graft copolymer, or may be composed of two or more of these plural components. Further, for example, a supramolecular fiber obtained by a supramolecular compound which is self-assembled by a non-covalent bond interaction with a low molecular compound such as trimethylamine can be used as the nanofiber.

As a method of application (dispersion method) of NF53 on the substrate 51, a method of directly depositing by a spinning method such as an electrospinning method, a composite melt spinning method, or a melt blowing method, a method of dispersing nanofibers which have been previously spun by an appropriate method on a substrate, a method of attaching a nanofiber which has been previously woven into a mesh to a substrate, a polymer which forms a mesh, or a gel of a supramolecular The method of spin coating on the substrate is not limited thereto, and any application method can be employed as long as the substrate 51 is not damaged. In particular, an electrospinning method capable of spinning at normal temperature and easily controlling the diameter of the nanofiber or the density of the web is preferred.

In the electrospinning method, the diameter of the nanofiber can be adjusted by adjusting the viscosity, conductivity, surface tension, solvent boiling point and the like of the spinning solution, as well as the application voltage, the distance between the nozzle and the substrate, and the solution supply speed. And control. Among these control factors, especially the viscosity and conductivity of the spinning solution can be utilized as a general control factor. Specifically, the viscosity of the spinning solution can be controlled by adjusting the molecular weight, concentration, and temperature of the spinning solution of the solute molecules (polymer or sol-gel precursor) contained in the spinning solution, and the conductivity of the spinning solution. The rate can be controlled by adding an electrolyte to the spinning solution. In general, the higher the molecular weight and the low concentration of the solute molecules contained in the spinning solution, and the greater the conductivity of the spinning solution in the range of the electrostatic induction that does not hinder the high electric field, the smaller the diameter of the nanofibers can be. . The molecular weight and concentration of the solute molecule can be selected according to an appropriate use as long as a uniform spinning solution can be prepared. Further, examples of the electrolyte include organic solvents such as pyridine, acetic acid, and amine, and inorganic salts such as lithium salts, sodium salts, potassium salts, and carbonates, and are not limited as long as a uniform spinning solution can be prepared.

In the electrospinning method, the control of the density of the nanofibers can be easily performed by controlling the electrospinning time. The density of the nanofibers gradually increases with the electrospinning time.

The diameter of the NF 53 applied to the substrate 51 depends on the resistance value or use of the transparent conductive film to be produced, and may be in the range of 100 to 3000 nm. In particular, when the transparency due to light scattering is lowered, it is preferably 2000 nm or less, and further preferably 1000 nm. under.

In order to function NF53 as an etch mask in the subsequent etching step, NF53 must be in close contact with substrate 51. When the adhesion is insufficient, the conductive portion of the produced transparent conductive film is defective in disconnection or the like, and the conductivity of the transparent conductive film is lowered. As a method of improving the adhesion between NF53 and the substrate 51, for example, it is effective to heat-treat at a glass transition temperature of NF53 or higher. Regarding the heat treatment temperature, it is considered to cause thermal damage to the substrate 51, for example, it is preferably treated at a relatively low temperature of 60 to 120 °C. The reason is that if excessive heat treatment is performed, there is a possibility that NF53 is modified.

<etching of substrate>

The substrate 51 is masked by the NF 53 on the substrate 51, and as shown in Fig. 6(b), the concave-convex pattern 35 of the random mesh structure is formed on the substrate 51 (step A2 of Fig. 5).

The etching of the substrate 51 can be performed by a wet etching method or a dry etching method. In order to etch the substrate 51 so that the processed end surface of the substrate 51 is more perpendicular, a dry etching method is preferable. The dry etching can be performed using any etching gas having a sufficiently large etching selectivity of the substrate 51 and the NF 53. When a tantalum substrate is used as the substrate 51, sulfur fluoride, oxygen, nitrogen, argon or the like can be used. Further, when a tantalum substrate having a hard mask made of SiOx is used as the substrate 51, SiOx etching using NF53 as a mask can be first performed using fluoroform, oxygen, nitrogen, argon or the like, and then used. Sulfur fluoride, oxygen, nitrogen, argon, or the like is subjected to Si etching with residual SiOx as a mask. Thus, by performing etching using a hard mask, the ratio of the height to the width of the convex portion of the concave-convex pattern 35 can be increased.

<Production of Resin Mold>

A resin having a first transfer pattern 45 obtained by inverting the uneven pattern 35 of the substrate 51 is produced. Mold 40 (refer to Fig. 6 (d)) (step A3 of Fig. 5). The resin mold 40 can be produced, for example, in the following manner.

First, a curable resin is applied onto the support substrate 71 to form a resin layer 57. As shown in FIG. 6(c), the resin layer 57 is pressed against the surface of the substrate 51 on which the uneven pattern 35 is formed, and the resin layer 57 is cured.

Examples of the support substrate 71 include a substrate made of an inorganic material such as a semiconductor material such as glass, tantalum or niobium carbide, or a metal material such as nickel, copper or aluminum, or an oxime resin or polyethylene terephthalate ( PET), polyethylene naphthalate (PEN), polycarbonate (PC), cycloolefin polymer (COP), polymethyl methacrylate (PMMA), polystyrene (PS), polyimine A resin substrate such as (PI) or polyarylate. Further, the thickness of the support substrate 71 can be set in the range of 1 to 500 μm.

As the curable resin, a resin such as photocuring or thermosetting, a moisture curing type, or a chemical curing type (two-liquid mixing) can be used. Specific examples thereof include epoxy, acrylic, methacrylic, vinyl ether, oxycyclobutane, amine ester, melamine, urea, polyester, polyolefin, and phenol. Various resins such as a cross-linking liquid crystal system, a fluorine-based, an anthrone-based or a polyamide-based monomer, an oligomer, and a polymer. The thickness of the resin layer 57 may range from 0.5 to 500 μm. When the thickness is less than the lower limit, the height of the concavities and convexities formed on the surface of the resin layer 57 tends to be insufficient. When the thickness exceeds the above upper limit, the influence of the volume change of the resin generated during curing may increase. The first transfer pattern 45 is formed.

As a method of applying a curable resin, for example, a spin coating method, a spray coating method, a dip coating method, a dropping method, a gravure printing method, a screen printing method, a letterpress printing method, a die coating method, or a shower curtain method may be employed. Various coating methods such as a coating method, an inkjet method, and a sputtering method. Further, the conditions for curing the curable resin vary depending on the type of the resin to be used. For example, the curing temperature may be in the range of room temperature to 250 ° C, and the curing time may be in the range of 0.5 minute to 24 hours. Further, it may be a method of hardening by irradiation with an energy ray such as an ultraviolet ray or an electron beam. In this case, the irradiation amount may be in the range of 20 mJ/cm ² to 10 J/cm ² .

Then, the substrate 51 is removed from the cured resin layer 57. The method of removing the substrate 51 is not limited to the mechanical peeling method, and a known method can be employed. Further, the resin layer 57 may be peeled off from the support substrate 71. Thus, as shown in FIG. 6(d), the resin mold 40 having the first transfer pattern 45 obtained by inverting the uneven pattern 35 of the substrate 51 is obtained.

<Production of metal mold>

A metal mold 50 having a second transfer pattern 55 obtained by inverting the first transfer pattern 45 of the resin mold 40 is produced (step A4 in FIG. 5). The metal mold 50 can be produced, for example, by electroforming or the like in the following manner.

First, a seed layer to be used as a conductive layer for electroforming is formed on the resin mold 40 having the first transfer pattern 45 by electroless plating, sputtering, vapor deposition, or the like. In order to make the current density uniform in the electroforming process and to make the thickness of the deposited metal layer constant, the seed layer may be 10 nm or more. As the material of the seed layer, for example, nickel, copper, gold, silver, platinum, titanium, cobalt, tin, zinc, chromium, gold-cobalt alloy, gold-nickel alloy, boron-nickel alloy, solder, copper-nickel-chromium alloy, tin can be used. A nickel alloy, a nickel-palladium alloy, a nickel-cobalt-phosphorus alloy, or the like.

Then, as shown in FIG. 6(e), a metal layer 59 is deposited on the seed layer by electroforming (electroplating). The thickness of the metal layer 59 can be, for example, a thickness of 10 to 30000 μm including the thickness of the seed layer. As the material of the metal layer 59 deposited by electroforming, any of the above-mentioned metal species which can be used as the seed layer can be used. The formed metal layer 59 is from the resin mold 40 It is desirable to have an appropriate hardness and thickness in terms of ease of handling such as peeling and washing.

Then, the resin mold 40 is peeled off from the metal layer 59 containing the seed layer obtained as described above to obtain the metal mold 50. The peeling can be carried out mechanically, or can be carried out by using an organic solvent which dissolves the resin mold 40, or an acid, a base or the like. After the peeling, the material components remaining on the surface of the metal mold 50 can be washed and removed. As the washing method, wet cleaning using a surfactant or the like or dry cleaning using ultraviolet rays or plasma can be used. Further, for example, an adhesive or an adhesive may be used to adhere and remove the remaining material components.

By the above steps A1 to A4, the metal mold 50 having the second transfer pattern 55 obtained by inverting the first transfer pattern 45 is obtained as shown in Fig. 6 (f). The convex portion 59c of the concave-convex pattern (second transfer pattern) 55 of the mold 50 has a linear shape extending on the surface of the mold 50 in a plan view, and constitutes a random mesh structure. The width W of the linear convex portion 59c may be in the range of 200 to 3000 nm, or may be in the range of 200 to 900 nm. Further, the height H of the convex portion 59c is 0.5 times or more, preferably 0.5 to 4 times the width W of the convex portion 59c.

<Formation of Conductive Parts>

Then, the conductive portion 13 constituting the random mesh structure 15 is formed on the surface of the transparent film 11 by using the metal mold 50 (see FIG. 7(c)) (step A5 of FIG. 5). Such a conductive portion 13 can be formed, for example, in the following manner.

First, a transparent resin layer 12 is formed by applying a curable resin to the transparent support substrate 73. As shown in FIG. 7(a), the transparent resin layer 12 is pressed against the surface of the mold 50 on which the second transfer pattern 55 is formed, and the transparent resin layer 12 is cured.

The application and hardening of the curable resin can be carried out in the same manner as the application and hardening of the curable resin in the production of the resin mold 40 described above.

Then, the self-curing transparent resin layer 12 peels off the metal mold 50. Thus, as shown in FIG. 7(b), the transparent resin layer 12 having the third transfer pattern 65 obtained by inverting the second transfer pattern 55 of the mold 50 and the transparent support substrate 73 are obtained. Membrane 11. The transparent resin layer 12 constituting the transparent film 11 has a (fitting) concave portion 11c corresponding to the convex portion 59c of the second transfer pattern 55 of the mold 50. That is, the recessed portion 11c has a linear shape extending over the surface of the transparent film 11 in a plan view, and constitutes a random mesh structure.

Further, as shown in FIG. 7(c), a conductive material is filled in the concave portion 11c of the transparent film 11. The filling method is not particularly limited. For example, a silver paste, a copper paste or an aluminum paste, or a metal paste composed of the composite materials can be filled in the concave portion 11c by an extrusion method (a doctor blade method). By the above steps A1 to A5, the linear conductive portion 13 including the transparent film 11 and extending over the transparent film 11 and constituting the random mesh structure 15 is produced, and the conductive portion 13 is electrically filled in the concave portion 11c. A transparent conductive film 10 composed of a material.

Furthermore, the metal mold 50 can be reused. That is, when the metal mold 50 is produced once, the plurality of transparent conductive films 10 can be produced using the mold 50. Therefore, according to the present production method, a large-area transparent conductive film can be produced simply and at low cost.

[Method for Producing Transparent Conductive Film of Second Embodiment]

The transparent conductive film 20 of the second embodiment can be produced by the following operation in the step of forming a conductive portion on the transparent film using the above-described metal mold.

First, as shown in FIG. 8(a), a conductive material is applied onto the convex portion 59c of the mold 50 to form a coating film 24. Examples of the conductive material that can be applied include silver paste, copper paste, aluminum paste, and a metal paste composed of the composite materials. As the coating method, a bar coating method, a spin coating method, a spray coating method, a dip coating method, a die coating method, an inkjet method, or the like can be used. The method of coating. By molding the mold 50 into a roll shape, the roll mold 50 is immersed in a conductive material that is thinly filled in the container and rotated, and the conductive material can be applied to the convex portion 59c of the mold 50. .

Then, as shown in FIG. 8(b), the metal mold 50 on which the coating film 24 of the conductive material is formed is pressed against the transparent film 21, whereby the coating film 24 is attached to the transparent film 21. Thereby, the coating film 24 is in close contact with the portion of the transparent film 21 that faces the convex portion 59c of the metal mold 50. Further, the transparent film 21 in which the coating film 24 is in close contact with the metal mold 50 is peeled off.

Thus, as shown in FIG. 8(c), the linear conductive portion 23 including the transparent film 21 and extending over the transparent film 21 and constituting the random mesh structure 25 is formed, and the surface of the conductive portion 23 with respect to the transparent film 21 is produced. The transparent conductive film 20 protruded for 21 s. Further, in order to further increase the aspect ratio of the conductive portion 23 to be produced, selective plating capable of selectively growing may be added in the height direction.

[Method for Producing Transparent Conductive Film of Third and Fourth Embodiments]

The transparent conductive film 10a of the third embodiment and the transparent conductive film 20a of the fourth embodiment can be produced, for example, as follows.

<patterning of NF>

Similarly to the NF spreading step, a random mesh structure composed of NF53a is formed on the substrate 51a, and as shown in Fig. 9(a), a mask 91 for NF patterning is formed on the substrate 51a. The position and shape of the mask 91 are the same as those of the plurality of specific regions 11p and 21p in which the random mesh structures 15a and 25a are formed in the transparent conductive films 10a and 20a of the third embodiment and the fourth embodiment. The mask 91 can be formed by any method such as photolithography.

Then, the (exposed) NF53a covered by the mask 91 is removed by etching. The etching of NF53a can be performed by any dry etching. Thereby, as shown in FIG. 9(b), The random mesh structure composed of NF53a is formed only in a specific region on the substrate 51a.

<Formation of lead wiring pattern>

As shown in FIG. 9(c), a lead-out wiring mask 93 is formed on the substrate 51a. The position and shape of the mask 93 are the same as those of the lead wires 17 and 27 in the transparent conductive films 10a and 20a of the third embodiment and the fourth embodiment. The mask 93 can be formed by any method such as screen printing.

When the substrate etching step is performed as described above, the concave-convex pattern 35a and the lead wiring pattern (the protruding portion for the lead wiring) 97 of the random mesh structure are formed on the substrate 51a as shown in FIG. 9(d). Furthermore, in the present manufacturing method, the substrate etching step and the lead wiring pattern forming step are simultaneously performed.

When the resin mold manufacturing step and the metal mold manufacturing step are performed using the substrate 51a, and the conductive portion forming step similar to the method for manufacturing the transparent conductive film 10 of the first embodiment is performed, as shown in FIG. 3(a) and FIG. The random mesh structure 15a composed of the conductive portion 13a shown in FIG. 4 is formed in the specific region 11p, and further includes the transparent conductive film 10a of the third embodiment in which the wiring 17 is drawn. In the same manner as the method of forming the conductive portion of the method for producing the transparent conductive film 20 of the second embodiment, the conductive portion forming step is the same as that of the method for manufacturing the transparent conductive film 10 of the first embodiment. (b) The random mesh structure 25a composed of the conductive portion 23a shown in FIG. 4 is formed in the specific region 21p, and further includes the transparent conductive film 20a of the fourth embodiment in which the wiring 27 is drawn. Moreover, in order to further increase the aspect ratio of the conductive portion 23a, selective plating capable of selective growth may be added in the height direction.

Furthermore, the patterning of NF can also be carried out by a lift-off method instead of the above etching method. That is, a mask having a specific region opening is formed on the substrate before the NF scattering by photolithography or the like. If the NF is spread on the substrate on which the mask is formed, the mask is removed by using a solvent or the like, and the mask is covered. NF is also removed, leaving only NF in specific areas. Thereby, the random network structure composed of NF can be formed only in a specific region on the substrate.

Further, the lead wiring pattern 97 may be formed of a desired material (resin, metal paste, etc.) by a screen printing method or the like instead of forming the mask on the substrate after the substrate etching step. The convex portion of the desired height is formed thereby. For example, the transparent conductive film 10b having the height H2 of the lead wire 17b higher than the height H1 of the conductive portion 13b can be manufactured as follows (see FIG. 10(d)). By increasing the height H2 of the lead wiring 17b, the resistance of the lead wiring 17b becomes lower.

First, similarly to the patterning step of NF described above, as shown in FIG. 10(a), the random network structure composed of NF53b is formed only in a specific region on the substrate 51b.

Then, the substrate etching step is performed, and as shown in FIG. 10(b), the concave-convex pattern 35b having a random mesh structure is formed on the substrate 51b.

Further, as shown in FIG. 10(c), a lead wiring pattern (lead wiring convex portion) 97b is formed on the substrate 51b. The height of the lead wiring convex portion 97b is higher than the height of the convex portion of the concave-convex pattern 35b. The position and the planar shape of the lead-out wiring convex portion 97b are formed to correspond to the position and planar shape of the lead-out wiring 17b in the manufactured transparent conductive film 10b. The material and formation method of the lead wiring pattern 97b are not particularly limited, and can be formed by any method such as screen printing.

When the substrate 51b is used, the resin mold manufacturing step and the metal mold manufacturing step are performed, and the conductive portion forming step similar to the method for manufacturing the transparent conductive film 10 of the first embodiment is performed, and the manufacturing process is performed as shown in FIG. 10(d). The random mesh structure including the conductive portion 13b is formed in a specific region, and further includes a transparent conductive film 10b having a lead line 17b having a height H2 higher than the height H1 of the conductive portion 13b.

[Examples]

Hereinafter, the transparent conductive film of the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples.

Example 1

In a solvent obtained by mixing DMF (N', N'-dimethylformamide) (manufactured by Wako Pure Chemical Industries, Ltd.) with THF (tetrahydrofuran) (manufactured by Tokyo Chemical Industry Co., Ltd.) in a volume ratio of 1:1, the polymerization is carried out. Styrene (weight average molecular weight 23 million) (manufactured by Polysciences Co., Ltd.) was dissolved to prepare a polystyrene solution having a concentration of 0.1% by weight. The polystyrene solution was used as a raw material (spinning solution), and an electrospinning device (ES-2000S2, manufactured by Fuence Co., Ltd.) was used on a Si wafer having a thermal oxide film having a thickness of 50 nm, and the distance between the electrodes was 15 cm. Polystyrene nanofibers were deposited (dispersed) for 10 seconds under conditions of a potential difference of 15 kV and a liquid delivery rate of 30 μL/min. The fibers obtained had an average fiber diameter of 1000 nm. Then, the Si wafer on which the thermal oxide film of the nanofibers was deposited was heat-treated at 130 ° C for 30 minutes, thereby preparing a Si crystal having a thermal oxide film attached to the nanofiber at an area ratio (coverage ratio) of 8.5%. circle.

Then, etching of the thermal oxide film with the nanofiber as a mask is performed by a parallel plate type reactive ion etching method. As the etching gas, a mixed gas of fluoroform and oxygen was used, and etching was performed for 115 seconds under conditions of an antenna power of 800 W, a bias power of 100 W, a fluoroform flow rate of 10 sccm, an oxygen flow rate of 50 sccm, and a pressure of 0.1 Pa. Thereby, a planar thermal oxide film corresponding to the planar shape (pattern) of the deposited nanofibers remains on Si.

Then, the Si wafer is etched by the inductively coupled reactive ion etching method using the thermal oxide film as a mask. As the etching gas, a mixed gas of sulfur hexafluoride, oxygen, and argon is used, and the antenna power is 600 W, the bias power is 50 W, the sulfur hexafluoride flow rate is 25 sccm, the oxygen flow rate is 50 sccm, the argon gas flow rate is 200 sccm, and the pressure is 0.07 Pa. Etched for 153 seconds. Thereby, an Si wafer having a concavo-convex pattern is obtained. The convex portion of the concave-convex pattern has a linear shape having a width of 1000 nm and a height of 4000 nm, and constitutes a random network structure in plan view. The obtained Si wafer having the uneven pattern was subjected to O ₂ ashing treatment for 2 minutes to remove foreign matter remaining on the surface, thereby producing a Si base mold having a random network structure.

A UV curable resin is dropped on the surface of the Si base mold on which the uneven pattern is formed, and the UV curable resin is sandwiched between the Si base mold and the PET film. The UV-curable resin was irradiated with UV light at 200 mJ/cm ^{2 for} 1 minute to harden the UV-curable resin. Thereafter, the UV curable resin and the PET film were mechanically peeled off from the Si base mold, and a resin mold (resin base mold) which reversed and transferred the uneven pattern formed on the Si base mold was obtained.

Then, using a sputtering apparatus, electroforming is performed on the surface of the resin mold to form a Ni seed layer required. In the sputtering, Ni was used as a target, 10 sccm Ar was supplied into the chamber, and the internal pressure was adjusted to 1 Pa. In this state, the input power was 300 W for 3 minutes. The resin mold forming the seed layer was placed in an electroless nickel plating solution, and the pH was adjusted to 5 to cause a reduction reaction, whereby a nickel electroformed layer having a thickness of 290 μm was formed on the seed layer. Then, the resin mold was peeled off from the nickel electroformed layer and the seed layer to obtain a metal mold (nickel mold) having a concave-convex pattern. The convex portion of the concave-convex pattern of the nickel mold constitutes a random network structure in plan view.

The UV curable resin was dropped on the surface of the nickel mold having the uneven pattern, and the UV curable resin was sandwiched between the metal mold and the PET film. The UV-curable resin was irradiated with UV light at 200 mJ/cm ^{2 for} 1 minute to harden the UV-curable resin. Then, the UV curable resin and the PET film were mechanically peeled off from the nickel mold to obtain a transparent film (resin film) having the same concavo-convex pattern as the above resin mold. The concave portion of the concave-convex pattern of the transparent film constitutes a random network structure in plan view. The surface of the obtained transparent film having a random network structure was subjected to corona discharge treatment, and the wettability (water contact angle) of the surface was changed from 85 to 13°. Thereafter, a slurry in which Ag nanoparticles were dispersed (manufactured by InkTec Co., Ltd., TEC-PM-010) was embedded in a concave portion of the transparent film by extrusion, and then heated at 120 ° C for 30 minutes to prepare a slurry. The solvent in the volatilization. Further, the surface of the transparent film in which Ag is buried in the concave portion is washed with ethanol.

A cross-sectional SEM photograph of the transparent conductive film produced as described above is shown in Fig. 11A. The conductive portion has a height of 4000 nm and a width of 1000 nm, and the ratio is 4.0. The sheet resistance of the transparent conductive film was 1.5 Ω/sq. Further, when the pattern was not visually recognized, no water ripple occurred in the case where two transparent conductive films were superposed on the display element.

Example 2

The same procedure as in Example 1 was carried out except that a polystyrene solution having a concentration of 0.05% by weight was used as the spinning solution, the dispersion time of the nanofibers was set to 16 seconds, and the etching time of the Si wafer was set to 16 seconds. The way to make the Si base mold. The average fiber diameter of the nanofibers was 500 nm, and the area ratio (coverage ratio) of the nanofibers attached to the Si wafer with the thermal oxide film was 6.8%. Further, the convex portion of the concave-convex pattern of the Si base mold has a linear shape having a width and a height of 500 nm, and constitutes a random network structure in a plan view.

A transparent conductive film was produced under the same conditions as in Example 1 using the obtained Si base mold having a random network structure. A SEM photograph of a cross section of the produced transparent conductive film is shown in Fig. 11B. The conductive portion has a height of 300 nm and a width of 500 nm, and the ratio is 0.6. The sheet resistance of the transparent conductive film was 25 Ω/sq. Further, when the pattern was not visually recognized, no water ripple occurred in the case where two transparent conductive films were superposed on the display element.

Comparative example 1

The same procedure as in Example 1 was carried out except that a polystyrene solution having a concentration of 0.072% by weight was used as the spinning solution, the dispersion time of the nanofibers was set to 10.5 seconds, and the etching time of the Si wafer was set to 8.2 seconds. The way to make the Si base mold. The average fiber diameter of the nanofibers was 700 nm, and the area ratio (coverage ratio) of the nanofibers attached to the Si wafer with the thermal oxide film was 6.3%. Further, the convex portion of the concave-convex pattern of the Si base mold has a linear shape having a width and a height of 700 nm, and constitutes a random network structure in a plan view.

A transparent conductive film was produced under the same conditions as in Example 1 using the obtained Si base mold having a random network structure. A cross-sectional SEM photograph of the produced transparent conductive film is shown in Fig. 11C. The height of the conductive portion was 150 nm and the width was 700 nm, and the ratio was 0.21. The transparent conductive film has a high sheet resistance and a resistance value of 57 Ω/sq. On the other hand, when the pattern was not visually recognized, water ripple was not generated when two transparent conductive films were superposed on the display element.

The present invention has been described above with reference to the embodiments. However, the transparent conductive film, the metal mold, and the manufacturing methods of the present invention are not limited to the above-described embodiments, and may be appropriately within the scope of the technical idea described in the claims. change.

[Industrial availability]

The transparent conductive film of the present invention has no pattern appearance and has low electrical resistance. Moreover, even if two sheets are overlapped on the display element (panel), no water ripple is generated. Further, a large-area transparent conductive film can be produced simply and at low cost. Therefore, the transparent conductive film of the present invention can be preferably used in various devices such as a touch panel, an electronic paper, and a thin film solar cell.

10‧‧‧Transparent conductive film

11‧‧‧Transparent film

11c‧‧‧ recess

11s‧‧‧ surface

12‧‧‧Transparent resin layer

13‧‧‧Electrical Department

13s‧‧‧ upper surface

20‧‧‧Transparent conductive film

21‧‧‧Transparent film

21s‧‧‧ surface

23‧‧‧Electrical Department

73‧‧‧Transparent support substrate

H‧‧‧ Height

W‧‧‧Width

Claims (12)

A transparent conductive film comprising: a transparent film and a linear conductive portion extending over the transparent film; wherein the conductive portion constitutes a random network structure, and the conductive portion has a width of 200 to 3000 nm, and the conductive portion The height of the portion is 0.5 times or more the width of the conductive portion. The transparent conductive film according to claim 1, wherein the transparent film has a concave portion, and the conductive portion is made of a conductive material filled in the concave portion. The transparent conductive film of claim 1, wherein the conductive portion protrudes from a surface of the transparent film. The transparent conductive film according to any one of claims 1 to 3, wherein the random network structure is formed in a plurality of specific regions arranged on a surface of the transparent film. The transparent conductive film of claim 4, further comprising a lead-out wiring formed on the transparent film, wherein the lead-out wiring is electrically connected to the random mesh structure formed in the plurality of specific regions. A metal mold having a concave-convex pattern, wherein the convex portion of the concave-convex pattern constitutes a random mesh structure, and a height of the convex portion is 0.5 times or more of a width of the convex portion. A method for manufacturing a metal mold, which is a method for manufacturing a metal mold having a convex portion of a random network structure, comprising: Dispersing a nanofiber on the substrate, and forming a random network structure composed of the nanofiber on the substrate; forming the random mesh on the substrate by using the nanofiber as a mask and etching the substrate a concave-convex pattern of a structure; a resin mold having a first transfer pattern obtained by inverting the uneven pattern of the substrate; and a metal layer laminated by electroforming on the first transfer pattern of the resin mold; The resin mold is removed, thereby forming a metal mold having a second transfer pattern obtained by inverting the first transfer pattern. The method for producing a metal mold according to claim 7, wherein the random network structure composed of the nanofibers is formed only in a specific region of the substrate. A method of producing a metal mold according to the seventh aspect of the invention is the method for forming a lead wiring pattern in the metal mold. A method for producing a transparent conductive film, comprising: manufacturing a metal mold by the manufacturing method according to any one of claims 7 to 9; and forming a random network structure on the surface of the transparent film using the metal mold Conductive part. The method for producing a transparent conductive film according to claim 10, wherein the forming the conductive portion includes: forming a transparent film having a third transfer pattern obtained by inverting the second transfer pattern of the metal mold ;and The conductive material is filled in the concave portion of the third transfer pattern of the transparent film. The method for producing a transparent conductive film according to claim 10, wherein the forming the conductive portion includes: applying a conductive material to a convex portion of the second transfer pattern of the metal mold; and coating the conductive material; The metal mold of the conductive material is pressed against the transparent film, and the conductive material is adhered to the transparent film.