JP5515828B2 - Low resistance transparent conductive film, method for producing the same, solar cell, and electronic device - Google Patents

Description

  The present invention relates to a low-resistance transparent conductive film, a method for producing the same, a solar cell, and an electronic device. Low resistance transparent conductive film having high transmittance, low surface resistance, and excellent productivity, a method for producing the same, a solar cell provided with the transparent conductive film, and the transparent conductivity The present invention relates to an electronic device provided with a film.

The transparent conductive film is indispensable as an electrode material for various display devices such as a liquid crystal display (LCD), a touch panel, and electronic paper. In recent years, it has been used in a wide range of fields such as solar cells and electrodes for organic EL (electroluminescence) illumination.
In particular, since solar cells are ideal energy resources with little environmental impact, they have been rapidly spreading in recent years. However, silicon-based solar cells, which are currently the mainstream, include high-temperature processing steps and vacuum processing steps in the manufacturing process. Therefore, the manufacturing costs are high, and in order to further spread in the future, the manufacturing costs must be reduced. Is essential. Therefore, research and development of various solar cells other than silicon-based materials have been actively conducted.

Among these solar cells, dye-sensitized solar cells can be manufactured using materials that are abundant in resources and relatively inexpensive, and the manufacturing process does not include a high-temperature processing step or a vacuum processing step. Therefore, a significant reduction in manufacturing costs can be expected compared to silicon.
In addition, since the dye-sensitized solar cell can be manufactured without performing a high-temperature treatment, it is possible to use a substrate having low heat resistance such as a resin film or a sheet material, and a lightweight and flexible solar cell. Battery module design is possible. In addition, by selecting the type of pigment, solar cells having various shades can be produced, and the design properties are excellent.

  On the other hand, organic EL lighting has attracted attention as a next-generation lighting because it has features such as high luminous efficiency, low calorific value, and low power consumption. Moreover, since it is surface emission, it is suitable for uniformly illuminating a wide area. Furthermore, a flexible base material such as a resin film or a sheet material can be used, and it is expected that a light, thin and flexible lighting device that has never been achieved can be realized.

In general, tin-doped indium oxide (ITO) or the like is used as a transparent electrode for such a dye-sensitized solar cell or organic EL lighting, but in order to obtain a transparent electrode having a lower resistance. Needs to increase the film thickness of the transparent electrode. However, when the film thickness of the transparent electrode is increased, the light transmittance is reduced and the manufacturing cost is increased, so that it is difficult to achieve both low resistance and high transmittance.
In particular, when a film substrate such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is used as the substrate, it is difficult to obtain a transparent conductive film with sufficiently low electrical resistance due to heat resistance problems. In addition, it is a problem to obtain a transparent conductive film having a low resistance.

For example, in a solar cell, if the electrical resistance of the transparent conductive film as an electrode is high, a loss due to heat generation becomes large when taking out the current generated by photoelectric conversion, which causes a decrease in the conversion efficiency of the solar cell. ing. Also in organic EL illumination, if the electrical resistance of the transparent electrode is high, the in-plane uniformity of light emission is reduced, and in some cases, uneven light emission occurs in the surface.
The influence of the problem caused by the high resistance value of these transparent electrodes becomes a serious problem as the size of the solar cell and organic EL illumination increases.
In the future, dye-sensitized solar cells and organic EL elements are not limited to small devices, but are expected to be applied to larger devices. In this case, how to reduce the heat loss caused by the high electrical resistance of the transparent electrode is essential for improving the device performance.

Therefore, on the surface of the substrate, a transparent electrode made of a metal film having a large number of net-like or lattice-like holes and tin-doped indium oxide (ITO) or the like is formed, and a metal oxide semiconductor film is formed on the transparent electrode, A solar cell provided with an organic dye-sensitized metal oxide semiconductor electrode in which an organic dye is adsorbed on the surface of the semiconductor film has been proposed (Patent Document 1).
Moreover, on the transparent resin film, a metal first conductive layer in which a number of fine wires are combined, a corrosion prevention layer covering the outer surface of the first conductive layer, a metal oxide second conductive layer covering the corrosion prevention layer, There has been proposed a dye-sensitized solar cell in which porous semiconductor electrodes are sequentially formed and a dye is supported on the surface of semiconductor fine particles of the porous semiconductor electrode (Patent Document 2).
Further, on the transparent substrate, a fine metal wire portion containing a conductive metal is formed by a method of exposing and developing a photosensitive silver salt, and carbon is formed so as to cover the surface of the transparent substrate including the fine metal wire portion. There has been proposed a dye-sensitized solar cell in which a paint containing conductive fine particles such as nanotubes is applied to form a light-transmitting conductive film (Patent Document 3).

JP 2003-123858 A JP 2005-158726 A JP 2008-288102 A

By the way, in the solar cell (patent document 1) and the dye-sensitized solar cell (patent document 2) provided with the conventional organic dye-sensitized metal oxide semiconductor electrode, after providing the metal film on the surface of the substrate, Since this metal film is etched by photolithography to form metal wiring, the manufacturing process becomes complicated and the manufacturing cost increases.
Further, when a metal wiring is formed by etching, the edge of the metal wiring becomes sharp. Therefore, it is difficult to form a uniform film when sputtering tin-doped indium oxide (ITO) or the like, and the obtained transparent conductive film There is a problem in that the in-plane film thickness becomes uneven, or pinholes, cracks and the like may occur at the boundary between the transparent conductive film, particularly the portion with and without the metal wiring. When such a film formation failure occurs in the transparent conductive film, the conductivity as the conductive film deteriorates, and when used as an electrode of a dye-sensitized solar cell, iodine in the electrolytic solution is produced in the transparent conductive film. There is a possibility that the metal wiring is corroded by penetrating into the transparent electrode from the defective portion of the film, and as a result, there is a risk of deterioration of characteristics over time such as reduction in conversion efficiency of the solar cell.

Moreover, in the dye-sensitized solar cell (patent document 3) provided with the translucent conductive film, the resistance value of the coating film obtained by apply | coating the coating material containing electroconductive fine particles, such as a carbon nanotube, is high, therefore There is a problem that sufficient conductivity cannot be imparted to the opening where the fine metal wire is not formed.
Thus, in various devices such as dye-sensitized solar cells and electroluminescence elements, display performance does not deteriorate even when the size is increased, electric resistance is low, light transmittance is high, and cost is low. There is a need for a transparent electrode that can be manufactured at the same time.

  The present invention has been made to solve the above-described problems, and has a low resistance transparent conductive film having a high light transmittance and a low electrical resistance, and the low resistance transparent conductive film is produced at low cost. Another object of the present invention is to provide a method for producing a low-resistance transparent conductive film that is excellent in productivity, and a solar cell and an electronic device provided with the low-resistance transparent conductive film.

  As a result of intensive studies on transparent conductive films used as electrodes of electronic devices such as dye-sensitized solar cells and electroluminescence elements, the present inventors have made fine metal wires on a flexible transparent substrate. A fine metal wire layer formed in a mesh shape is provided, a transparent resin layer is provided so as to cover the inside of the metal fine wire layer and its peripheral portion, and a transparent conductive film is provided so as to cover the fine metal wire layer and the transparent resin layer. When it was provided, it was found that the light transmittance of the transparent conductive film can be kept high and the electrical resistance can be sufficiently lowered, and the present invention has been completed.

That is, the low-resistance transparent conductive film of the present invention comprises a transparent base material having flexibility, a metal fine wire layer formed on the transparent base material and having fine metal wires formed in a mesh shape, and the metal fine wire layer. A transparent resin layer provided so as to cover the inside of the mesh and its peripheral edge, and a transparent conductive film provided so as to cover these metal fine wire layer and transparent resin layer, and the metal fine wire is a part of the surface thereof The cross-sectional shape is arcuate in the cross-sectional direction or is inclined with respect to the transparent substrate, so that the thickness in the cross-sectional direction decreases toward the outside, and the end of the transparent resin layer Is in contact with the portion where the thickness of the thin metal wire in the cross-sectional direction decreases, and at the end of the transparent resin layer, an angle formed by the tangent of the surface of the transparent resin layer and the tangent of the surface of the fine metal wire (theta) is this satisfying 120 ° ≦ θ ≦ 180 ° The features.

The average thickness of the transparent resin layer is preferably thinner than the maximum thickness of the fine metal wires, and the thickness of the central portion of the transparent resin layer is preferably smaller than the thickness of the outer peripheral portion.
It is preferable that at least a part of the highest part of the thin metal wire layer is in direct contact with the transparent conductive film.

  The method for producing a low-resistance transparent conductive film of the present invention comprises a portion having a shape in which the thickness in the cross-sectional direction decreases toward the outside directly or through a base layer on a flexible transparent substrate. A fine metal wire layer comprising the fine metal wires is formed, and then a transparent resin layer-forming coating material containing a solvent and a resin component is formed on the transparent substrate having the fine metal wire layer with a maximum thickness of 0. The coating is applied at a film thickness of 5 times or more and 5 times or less, and then dried to form a transparent resin layer covering the inside of the network of the metal fine wire layer and the peripheral portion thereof, and then these metal fine wire layer and transparent A transparent conductive film is formed so as to cover the resin layer.

  The solar cell of the present invention includes the low resistance transparent conductive film of the present invention.

  The electronic device of the present invention includes the low-resistance transparent conductive film of the present invention.

According to the low resistance transparent conductive film of the present invention, a transparent base material having flexibility, a metal fine wire layer formed on the transparent base material to form a fine metal wire in a mesh shape, and the metal fine wire layer A transparent resin layer provided so as to cover the inside of the mesh and its peripheral portion, and a transparent conductive film provided so as to cover these metal fine wire layer and transparent resin layer , and the metal fine wire is a part of the surface thereof The cross-sectional shape is arcuate in the cross-sectional direction or is inclined with respect to the transparent base material, so that the thickness in the cross-sectional direction decreases outward, and the end of the transparent resin layer is made of metal. The angle (θ) between the tangent of the surface of the transparent resin layer and the tangent of the surface of the metal fine wire is 120 ° ≦ θ ≦ at the end of the transparent resin layer in contact with the portion where the thickness of the thin wire is reduced in the cross-sectional direction. since satisfying 180 °, high coercive light transmittance to visible light While, the electrical resistance can be reduced sufficiently. Therefore, a transparent conductive film having both high light transmittance and low electrical resistance can be provided.

  According to the method for producing a low-resistance transparent conductive film of the present invention, a mesh-like and cross-sectional thickness decreases outwardly directly or via a base layer on a flexible transparent substrate. Forming a fine metal wire layer comprising a fine metal wire having a portion, and then, on the transparent substrate having the fine metal wire layer, a transparent resin layer-forming coating material containing a solvent and a resin component, with a maximum thickness of the fine metal wire. Coating is performed with a film thickness of 0.5 times or more and 5 times or less, and then dried to form a transparent resin layer covering the inside of the network of the metal fine wire layer and its peripheral portion, and then these metal fine wire layers Since the transparent conductive film is formed so as to cover the transparent resin layer, it is possible to manufacture a transparent conductive film having both high light transmittance and low electrical resistance at a low cost and with high productivity in a simple process. it can.

  According to the solar cell of the present invention, since the low resistance transparent conductive film of the present invention is provided, incident light can be reduced by using a transparent conductive film having high light transmittance for visible light and sufficiently low electrical resistance. It can be introduced into the power generation cell with almost no attenuation, and the electricity generated in this power generation cell can be taken out with very little loss. Therefore, the power generation loss due to the transparent conductive film in the solar cell can be greatly reduced, and the solar cell can be further increased in size and improved in power generation efficiency.

  According to the electronic device of the present invention, since the low-resistance transparent conductive film of the present invention is provided, this transparent conductive film can be obtained by using a transparent conductive film having high light transmittance for visible light and sufficiently low electrical resistance. The heat generated from the conductive film can be greatly reduced. Therefore, the heat generation due to the transparent conductive film in the electronic device can be greatly reduced, and the electronic device can be further increased in size and saved in energy.

It is a partial expanded sectional view which shows the low resistance transparent conductive film of the 1st Embodiment of this invention. It is a partial enlarged plan view which shows the low resistance transparent conductive film of the 1st Embodiment of this invention. It is sectional drawing which shows the specific example of the cross-sectional shape of the metal fine wire of the low resistance transparent conductive film of the 1st Embodiment of this invention. It is a partial expanded sectional view which shows the low resistance transparent conductive film of the 2nd Embodiment of this invention. It is a partial enlarged plan view which shows the low resistance transparent conductive film of the 2nd Embodiment of this invention. It is a partial expanded sectional view which shows the low resistance transparent conductive film of the 3rd Embodiment of this invention.

The form for implementing the low resistance transparent conductive film of this invention, its manufacturing method, and an electronic device is demonstrated.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

[First Embodiment]
FIG. 1 is a partially enlarged sectional view showing a low-resistance transparent conductive film 1 according to the first embodiment of the present invention, and FIG. 2 is a partially enlarged plan view showing the low-resistance transparent conductive film 1.
This low-resistance transparent conductive film 1 includes a flexible transparent base material 11, a primer layer (underlayer) 12 provided on the surface of the transparent base material 11, and fine metal wires 13 on the primer layer 12. The fine metal wire layer 14 formed by providing the mesh, the transparent resin layer 15 provided so as to cover the inside of the mesh of the fine metal wire layer 14 and the peripheral portion thereof, and the fine metal wire layer 14 and the transparent resin layer 15. And a transparent conductive film 16 provided so as to cover.

The transparent substrate 11 is preferably a resin film having transparency with respect to visible light and flexibility, and a polyester resin can be particularly preferably used.
The primer layer 12 is an underlayer provided for improving the pattern accuracy of the fine metal wires 13 and the transparent resin layer 15 and for improving the adhesion between the transparent substrate 11 and the fine metal wires 13 and the transparent resin layer 15. Usually, it is a layer containing an inorganic oxide and an organic polymer. The material of the primer layer 12 can be appropriately set in consideration of the materials of the transparent base material 11, the fine metal wires 13, and the transparent resin layer 15, but the fine metal wires 13 and the transparent resin layer 15 with respect to the transparent base material 11 can be set. The primer layer 12 can be omitted if the adhesiveness is good.

The fine metal wire layer 14 is composed of, for example, a fine metal wire 13 having a planar shape of a mesh pattern.
It is preferable that the line width (L) of the metal fine wire 13 in this metal fine wire layer 14 is 5-100 micrometers, and a line space | interval (P) is 100-5000 micrometers. Here, if the line width (L) is 5 μm or less, it is difficult to obtain sufficient conductivity, and if it exceeds 100 μm, the fine metal wire layer 14 is easily visible, which is not preferable. Further, if the line spacing (P) is less than 100 μm, the light transmittance is lowered, and if it exceeds 5000 μm, it is difficult to obtain sufficient conductivity, which is not preferable.

  The thickness (T) of the metal fine wire layer 14 is preferably 1.0 μm to 9.0 μm. The reason why the thickness (T) of the fine metal wire layer 14 is limited to the above range is that if the thickness is less than 1.0 μm, a sufficiently low resistance as the fine metal wire layer 14 cannot be obtained. When the thickness exceeds 0 μm, a step (unevenness) between the portion where the mesh-like fine metal wire layer 14 is formed on the primer layer 12 and the opening 17, that is, the portion where the primer layer 12 is exposed becomes large. This is not preferable because the formation of the transparent resin layer 15 and the uniform film formation of the transparent conductive film 16 are difficult.

The cross-sectional shape of the fine metal wires 13 constituting the fine metal wire layer 14 is such that at least a part of the surface is arcuate in the cross-sectional direction or is inclined with respect to the surface of the transparent base material 11. It has a portion having a shape in which the thickness in the cross-sectional direction decreases toward the outside.
FIG. 3 shows a specific example of the cross-sectional shape of the fine metal wire 13.

3 (a) and 3 (b), the entire surface of the fine metal wire 13 has an arc shape in the cross-sectional direction, so that the cross section has a shape like a substantially semi-elliptical shape or a convex lens shape. ) Has a triangular cross section because the surface is uniformly inclined from the center toward both ends.
Moreover, you may have a flat part in a center part like FIG.3 (d)-(e), and both ends are transparent base materials 11 like FIG.3 (f)-(g). It may be substantially perpendicular to the surface. Furthermore, these elements may be combined. Further, as shown in FIG. 3H, the arc-shaped portion may form a concave surface.

Here, when the thin metal wire 13 has a shape such as a rectangle having a sharp edge, the transparent conductive film 16 formed on the thin metal wire layer 14 is formed at the edge of the thin metal wire 13. Film formation defects such as insufficient thickness and cracks are likely to occur.
In the thin metal wire 13 of the present embodiment, there is no edge portion if the cross-sectional shape is as shown in FIGS. 3A, 3 </ b> B, 3 </ b> D, and 3 </ b> F. Also in the transparent conductive film 16 to be formed, there is no risk of film formation defects such as insufficient film thickness and occurrence of cracks.

On the other hand, when the thin metal wire 13 has a cross-sectional shape as shown in FIGS. 3C, 3E, and 3G, since the edges 18, 18 ′, and 18 ″ exist, the upper portion of the thin metal wire layer 14 is present. In the formed transparent conductive film 16, there is a risk of film formation failure such as insufficient film thickness or cracks. In order to prevent this problem, the angles α, α ′, α ″ of the edges are 180. It is preferable to be close to °, specifically,
150 ° ≦ α (α ′, α ″) ≦ 180 °
It is preferable that

  For example, the angle of the edge 20 shown in FIG. 3G is 115 ° or less. The edge 20 has a shape in which the end portion 19 of the transparent resin layer 15 has a reduced thickness in the cross-sectional direction of the thin metal wire 13. Since it is embedded in the transparent resin layer 15 by being formed so as to be in contact with the portion it has, there is no problem even if a sharp edge is formed.

The transparent resin layer 15 reduces the level difference (unevenness) generated between the fine metal wire layer 14 formed in a mesh shape and the opening 17, and the transparent conductive film 16 formed on the fine metal wire layer 14 and the opening 17. Is provided in order to form the film more uniformly.
The transparent resin layer 15 is provided in the mesh of the fine metal wire layer 14, that is, in the opening 17, and is provided so as to overlap the fine metal wire 13 so as to cover the peripheral edge of the opening 17. The portion 19 is in contact with a portion having a shape in which the thickness in the cross-sectional direction of the fine metal wire decreases. At the end 19, the angle (θ) formed by the tangent (T 1) on the surface of the transparent resin layer 15 and the tangent (T 2) on the surface of the thin metal wire 13 is 120 ° ≦ θ ≦ 180 °.
By setting it as such a shape, the film-forming defect of the transparent conductive film 16 formed on the metal fine wire layer 14 and the transparent resin layer 15 can be prevented.

  By the way, when the transparent conductive film 16 is formed, if there is an edge in the base, a defective film formation of the transparent conductive film 16 tends to occur at the edge portion. Therefore, as shown in FIG. 3 (b), when the transparent resin layer 15 is in contact with the thin metal wire 13 with a uniform thickness and the end 19 'is formed, the end 19' Since a clear edge is formed between the surface of the transparent resin layer 15, it is more preferable that there is no edge.

  Therefore, as shown in FIG. 3A, the thickness of the transparent resin layer 15 located at the end of the opening 17 is gradually increased and the transparent resin layer 15 rides on the fine metal wires 13. By gradually increasing the slope of the surface of the transparent resin layer 15 by forming the forward tapered shape portion 21, the surface of the transparent resin layer 15 and the surface of the fine metal wire 13 are brought into gentle contact with each other. Is preferred. With such a shape, it is possible to obtain a state where there is no edge between the surface of the transparent resin layer 15 and the surface of the thin metal wire 13, that is, θ = 180 °. Therefore, when forming the transparent conductive film 16 on the thin metal wire layer 14 and the transparent resin layer 15, it is possible to stack the uniform transparent conductive film 16 having a small film thickness variation and free from defects such as cracks and pinholes. it can.

  In addition, since the edge formed by the transparent resin layer 15 and the fine metal wire 13 is concave, the film thickness of the transparent conductive film 16 may be excessive at this edge, but it occurs at the convex edge. Insufficient film thickness and cracks are unlikely to occur. That is, the influence of film formation failure on the transparent conductive film 16 is lower than that of the convex edge. Therefore, the allowable range is 60 °, which is higher than the convex edge 18 on the thin metal wire 13.

  By making the transparent resin layer 15 into the shape as described above, the average thickness of the transparent resin layer 15 is thinner than the maximum thickness of the fine metal wires 13, and the thickness of the central portion of the transparent resin layer 15 is compared with the thickness of the outer peripheral portion. Thin shape. And forming the transparent conductive film 16 on the transparent resin layer 15 having such a shape and the fine metal wire layer 14 having the above-described shape means that the transparent conductive film 16 having a uniform and good characteristic can be obtained. In addition, it has the following advantages.

  First, the fine metal wire layer 14 is not completely covered with the transparent resin layer 15, and the highest portion (vertex portion) of the fine metal wire 13 is exposed. Therefore, since the transparent conductive film 16 and the metal fine wire layer 14 formed thereon are in direct contact, the electrical connection between the metal fine wire layer 13 and the transparent conductive film 15 is in a good state, As a result, the low resistance transparent conductive film 1 having a low electrical resistance over the entire film can be obtained.

Next, easiness of film formation in the transparent resin layer 15 is mentioned.
That is, the average thickness of the transparent resin layer 15 only needs to be thinner than that of the thin metal wire layer 14, and the range can be arbitrarily selected within a range in which the characteristics of the transparent conductive film 16 do not deteriorate. The range of the thickness of the transparent resin layer 15 depends on the shape of the thin metal wire 13 and the transparent resin layer 15, but can be set, for example, in a range from about 1/40 to about 2/3 of the thickness of the thin metal wire layer 14.

  On the other hand, when it is necessary to make the thickness of the thin metal wire layer and the transparent resin layer substantially the same as in the conventional transparent conductive film, the film thickness of the transparent resin layer is strictly set. Need to control. This is because when the transparent resin layer is thin, defective film formation of the transparent conductive film occurs at the boundary between the metal fine wire layer and the transparent resin layer, while when the transparent resin layer is thick, the metal fine wire layer is transparent. It is because the electrical connection between the transparent conductive film and the metal fine wire layer becomes poor because the resin layer is completely covered, and the conductivity of the film is lowered.

Further, since the surface area of the conductive portion is increased because the transparent conductive film 16 is not flattened but gently rugged, for example, the low-resistance transparent conductive film 1 of the present invention is applied to the dye-sensitized solar cell. When used as a light receiving side electrode of a battery, the current extraction efficiency can be improved.
Furthermore, since the transparent resin layer 15 has a concave lens shape and diffuses light, for example, when the low-resistance transparent conductive film 1 of the present invention is used as a light-receiving side electrode of a dye-sensitized solar cell, it is shielded by a thin metal wire. Since the light also enters the portion where the light is applied, it is possible to reduce the influence of a decrease in conversion efficiency caused by a decrease in transmittance due to the fine metal wire.

[Second Embodiment]
FIG. 4 is a partially enlarged sectional view showing a low resistance transparent conductive film 31 according to a second embodiment of the present invention, and FIG. 5 is a partially enlarged plan view showing the low resistance transparent conductive film 31.
The low-resistance transparent conductive film 31 includes a flexible transparent base material 11, a primer layer (underlayer) 12 provided on the surface of the transparent base material 11, and fine metal wires 35 on the primer layer 12. The fine metal wire layer 34 formed by providing the thin metal wire layer 34, the transparent resin layer 15 provided so as to cover the inside of the mesh of the fine metal wire layer 34 and the peripheral edge thereof, and the fine metal wire layer 34 and the transparent resin layer 15 are provided. And a transparent conductive film 16 provided so as to cover it.

As shown in FIG. 3A, the cross-sectional shape of the fine metal wire 35 is formed by a curve or a straight line having a convex structure that draws an arc, such as a substantially semi-elliptical shape or a convex lens shape. Such a cross-sectional shape is possible by forming the fine metal wire 35 by using both the printing method and the plating method.
In addition, as shown in FIG. 3A, the cross-sectional shape of the transparent resin layer 15 is such that the thickness near the end of the transparent resin layer 15 is gradually increased, and the transparent resin layer 15 runs on the thin metal wire 35. By forming the forward taper-shaped portion 21 by taking various forms, the surface of the transparent resin layer and the surface of the fine metal wire come into gentle contact with each other by gradually increasing the inclination of the surface of the transparent resin layer. Yes.
A specific example of the cross-sectional shape of the fine metal wire 35 is the same as the cross-sectional shape of the fine metal wire 13 of the first embodiment shown in FIG.

  The transparent substrate 11 is preferably a resin film that is transparent to visible light and has flexibility, such as an epoxy resin, a silicone resin, an acrylic resin, a butyral resin, a polyester resin, a phenol resin, a melamine resin, and an olefin. Examples thereof include resins, cycloolefin resins, norbornene resins. In particular, a polyester resin can be suitably used because it is excellent in transparency and inexpensive.

  The primer layer 12 is a base layer provided to improve the pattern accuracy of the fine metal wire layer 13 and the transparent resin layer 14, for example, a metal oxide such as alumina, titania, zirconia, or an inorganic oxide such as silica. And a layer containing an organic polymer. The material of the primer layer 12 can be appropriately set in consideration of the materials of the transparent substrate 11, the fine metal wire layer 13, and the transparent resin layer 14.

  The fine metal wire 35 covers the thin film catalyst ink layer (catalytic mesh layer) 32 formed in a mesh pattern by a printing method and the catalyst ink layer 32 by an electroless plating method or an electroplating method. And a metal layer 33 having a mesh pattern identical to the mesh pattern of the catalyst ink layer 32.

The catalyst ink layer 32 is composed of a composite material including oxide fine particles supporting noble metal fine particles and an organic polymer. In the catalyst ink layer 32, by supporting the noble metal fine particles on the oxide fine particles, the ink material containing the oxide fine particles carrying the noble metal fine particles and the organic polymer has a thixotropic property. This ink material has rheological properties suitable for various types of printing, and a printing pattern with excellent dimensional stability can be obtained.
Examples of the noble metal fine particles include fine particles of palladium, platinum, gold, silver and the like. Two or more kinds of these noble metal fine particles may be mixed and used.
Examples of the oxide fine particles include metal oxide fine particles such as alumina, zinc oxide, zirconia, and titania. Two or more kinds of these metal oxide fine particles may be mixed and used.

  The ratio (N / M) of the noble metal fine particles (N) to the oxide fine particles (M) is preferably 0.5 / 99.5 to 5/95 by mass ratio, more preferably 1/99 to 2/98. is there. Here, when the ratio of the noble metal fine particles is lower than the above range, it does not function as a catalyst for electroless plating. On the other hand, when the ratio is higher than the above range, the function as a catalyst for electroless plating is saturated. At the same time, a precious metal that is more expensive than necessary is used, which increases the manufacturing cost.

  The organic polymer may be any resin that has printing suitability such as pattern reproducibility and is resistant to the plating solution used to form the metal layer 22, and is a cellulose derivative, rosin ester resin, acrylic resin, polyvinyl Examples include butyral resin and polyurethane resin. Two or more of these resins may be mixed and used.

Further, the ratio (NM / R) of the oxide fine particles (NM) supporting the noble metal fine particles to the organic polymer (R) is preferably 40/60 to 80/20, more preferably 60 / 40-70 / 30.
Here, if the ratio of the oxide fine particles (NM) supporting the noble metal fine particles is lower than the above range, the noble metal fine particles are almost covered with the organic polymer and cannot function as a catalyst for electroless plating. On the other hand, if it is higher than the above range, the printability is deteriorated and the curing of the printed film by the organic polymer is insufficient, and as a result, the adhesion to the transparent substrate 11 provided with the primer layer 12 is improved. It is because it becomes impossible to obtain.

  The catalyst ink layer 32 preferably contains a pigment when the fine line pattern needs to be colored according to the application. For example, when the thin metal wire layer 34 is colored black to improve the contrast of the transparent conductive film 31, a black pigment such as carbon black is suitable. In addition, for example, in applications such as dye-sensitized solar cells, when it is necessary to make it difficult to visually recognize the thin metal wire layer 34 due to its design, it is similar to the dyes used in the dye-sensitized solar cells. Color pigments may be included in the catalyst ink layer 32.

The thickness of the catalyst ink layer 32 is, for example, preferably 0.3 μm to 3.0 μm, more preferably 0.8 μm to 1.5 μm.
Here, when the thickness of the catalyst ink layer 32 is less than 0.3 μm, the amount of metal deposited by electroless plating decreases, and as a result, the metal layer 33 having a sufficiently low resistance value cannot be obtained, which is not preferable.

  On the other hand, when the thickness of the catalyst ink layer 32 exceeds 3.0 μm, when the metal layer 33 is formed on the catalyst ink layer 32, the portion where the mesh-like metal fine wire layer 34 is formed on the primer layer 12; The step (unevenness) between the opening 17 formed between the fine metal wire layers 34, that is, the portion where the primer layer 12 is exposed, is increased, and the formation of the transparent resin layer 15 and the transparent conductivity, which are later steps, are increased. Since uniform film formation of the film 16 becomes difficult, it is not preferable. Further, if the catalyst ink layer 32 becomes too thick, there is a possibility that the adhesion between the primer layer 12 and the metal fine wire layer 34 is lowered. That is, since the catalyst ink layer 32 usually does not have conductivity, it is preferable that the catalyst ink layer 32 is thin if a metal layer 33 having a sufficiently low resistance value can be obtained.

The metal layer 33 is for imparting sufficient conductivity to the transparent conductive film 31 and is composed of one or more metal layers.
A portion of the metal layer 33 in contact with the catalyst ink layer 32 is formed by depositing metal so as to cover the catalyst ink layer 32 having a mesh pattern by an electroless plating method. As the metal constituting the portion in contact with the catalyst ink layer, any metal or alloy that can be deposited by electroless plating can be used, for example, nickel, cobalt, copper, silver, gold, platinum, or these metals. And the like. Among these, copper is preferably used because it is excellent in electrical conductivity and inexpensive.

  Here, when higher conductivity is required for the transparent conductive film 31, after depositing a metal by an electroless plating method, a metal may be further laminated by an electroplating method. In this case, as a metal to be laminated, any metal or alloy that can be deposited by electroplating can be used, but copper is preferable from the viewpoint of electrical conductivity and cost.

  When a metal that is easily oxidized and inferior in corrosion resistance, such as copper, is used as the metal constituting the metal layer 33, it is preferable that a metal having higher corrosion resistance is further laminated on the metal layer. Examples of such a metal having high corrosion resistance include nickel, cobalt, chromium, zinc, tin, tungsten, platinum, gold, and alloys of these metals. Such a metal having high corrosion resistance can form a metal layer by, for example, electroplating, electroless plating, displacement plating, or chemical conversion treatment. Further, instead of coating a metal having high corrosion resistance, the surface of the metal layer 33 is electrodeposited by using a paint in which conductive carbon black is dispersed in an electrodeposition resin or a paint in which a conductive polymer is dissolved or dispersed. Corrosion resistance can also be improved by painting. At this time, in order not to hinder the conductivity between the fine metal wire layer 34 and the transparent conductive film 16, the thickness of the coating film formed by electrodeposition coating is preferably 2 μm or less.

  The film thickness of the metal layer 33 is preferably 1.0 μm to 6.0 μm. The reason why the film thickness of the metal layer 33 is limited to the above range is that if the film thickness is less than 1.0 μm, a sufficiently low resistance cannot be obtained, while if it exceeds 6.0 μm, The level difference (unevenness) between the portion where the mesh-like fine metal wire layer 14 is formed and the opening 17, that is, the portion where the primer layer 12 is exposed becomes large, and the transparent resin layer 15, which is a later process, This is not preferable because formation and uniform film formation of the transparent conductive film 16 are difficult.

  The thin metal wire layer 34 preferably has a line width (L) of 5 to 100 μm and a line interval (P) of 100 to 5000 μm. Here, if the line width (L) is 5 μm or less, it is difficult to obtain sufficient conductivity, and if it exceeds 100 μm, the fine metal wire layer 34 is easily visible, which is not preferable. Further, if the line spacing (P) is less than 100 μm, the light transmittance is lowered, and if it exceeds 5000 μm, it is difficult to obtain sufficient conductivity, which is not preferable.

The ratio (T / L) between the line width (bottom width: L) and the maximum height (T) in the cross-sectional shape of the fine metal wire 35 is expressed by the following equation (1).
0.05 ≦ T / L ≦ 0.5 (1)
It is preferable to satisfy.
Here, when the ratio (T / L) between the line width (L) and the height (T) of the highest portion is larger than the above range, the portion where the fine metal wire 35 is formed on the primer layer 12 The step (unevenness) between the opening 17 and the opening 17 changes abruptly. As a result, even when there is no sharp edge in the cross-sectional shape of the fine metal wire 35, the transparent conductive material formed on the fine metal wire 35 Film formation defects such as non-uniform film thickness, cracks, and pinholes occur.
On the other hand, when the ratio (T / L) between the line width (L) and the highest part height (T) is smaller than the above range, it is difficult to obtain a transparent conductive film having a sufficiently low resistance value. This is not preferable.

As described above, the ratio (T / L) between the line width (L) and the height (T) of the highest portion in the cross-sectional shape of the fine metal wire 35 constituting the fine metal wire layer 34 satisfies the above formula (1). If there is, it is possible to prevent film formation defects such as non-uniformity of the film thickness of the transparent conductive film 16 and generation of cracks and pinholes, and the uniform transparent conductive film 16 is formed on the metal thin wire layer 34 and the opening 17. Can be formed.
The ratio (T / L) between the line width (L) of the fine metal wire 35 and the height (T) of the highest part is determined by the design of the printing plate making used in the production method of the present embodiment to be described later, the catalyst It can be adjusted by the conditions for transferring the ink to the primer layer 12, the thickness of the metal layer 22 deposited by plating, and the like.

  The transparent resin layer 15 is provided so as to overlap the fine metal wire 35 so as to cover the mesh of the fine metal wire layer 34, that is, the opening 17 and the peripheral edge of the opening 17. The thin metal wire 35 is in contact with a portion having a shape in which the thickness in the cross-sectional direction decreases. Further, the thickness of the transparent resin layer 15 located at the end of the opening 17 is gradually increased, and the forward tapered shape portion 21 is formed by taking the form in which the transparent resin layer 15 rides on the thin metal wire 35. .

  As described above, by providing the transparent resin layer 15 so as to cover the mesh of the fine metal wire layer 34, that is, the inside of the opening 17 and the peripheral edge of the opening 17, the unevenness between the fine metal wire layer 34 and the opening 17 is provided. Therefore, when the transparent conductive film 16 is formed on the thin metal wire layer 34 and the transparent resin layer 15, the variation in film thickness is small, and there is no defect such as cracks and pinholes. A transparent conductive film 15 can be formed.

  Further, since the fine metal wire layer 34 is not completely covered with the transparent resin layer 15, the highest part of the fine metal wire layer 34 is in direct contact with the transparent conductive film 16. As a result, the transparent conductive film 31 having a low electrical resistance is obtained.

The transparent resin layer 15 is coated with a coating for forming a transparent resin layer containing a transparent resin and an organic solvent so as to cover the inside of the opening 17 and the peripheral edge of the opening 17, dried, and then as necessary. It is formed by curing.
In order to provide the transparent resin layer 15 in the opening 17 and only at the peripheral edge of the opening 17, the liquid physical properties of the coating for forming the transparent resin layer and the wet film thickness (before drying) This is possible by adjusting the film thickness of the coating film to an appropriate range.

The liquid properties of the transparent resin-forming coating material are not particularly limited, but as a rough guide, the surface tension is preferably 35 N / m or less, and the viscosity is preferably 500 mPa · s or less.
If the surface tension and viscosity are designed to be within the above ranges, the transparent resin-forming coating material is applied onto the transparent base material 11 on which the fine metal wire layer 34 is formed, or the coating and drying stages. When the thickness of the coating becomes thinner than the height (T) of the highest portion of the fine metal wire layer 34, the paint applied near the highest portion (top surface) of the fine metal wire layer 34 is the highest portion ( The transparent resin layer 15 is formed only in the opening 17 and the peripheral edge of the opening 17.

  The transparent resin layer-forming coating material preferably contains at least one organic solvent having a boiling point of 120 ° C. or higher. When the organic solvent having a boiling point of 120 ° C. or higher is not included at all, the evaporation rate of the organic solvent in the paint in the drying process increases, and the paint moves from the highest portion (top surface) of the fine metal wire layer 34 to the opening 17. It is because it dries before moving and the paint may remain near the highest portion (top surface) of the fine metal wire layer 34.

  In addition, when the transparent resin layer forming coating material is applied, if the wet film thickness is large and the ratio of the amount of resin contained in the coating material is high, the thickness of the transparent resin layer 15 after drying and curing is metal. It is thicker than the fine wire layer 34, and the fine metal wire layer 34 may be completely covered with the transparent resin layer 15. Therefore, it is necessary to control the thickness of the transparent resin layer 15 by adjusting the amount of the transparent resin contained in the transparent resin layer forming coating material and appropriately adjusting the wet film thickness. The wet film thickness is not particularly limited, but is preferably 0.5 to 5 times the maximum thickness of the fine metal wire 35. For example, the content of the transparent resin in the paint is 10% by mass. In this case, the thickness is preferably 5 to 40 μm.

The resin constituting the transparent resin layer 15 is not particularly limited as long as it is a transparent resin. For example, acrylic resins, polyester resins, polyurethane resins, cellulose derivatives and other thermoplastic resins, phenol resins, urea Examples include thermosetting resins such as resins, melamine resins, polyurethane resins, epoxy resins and polysiloxane resins, UV curable resins such as acrylic monomers, methacrylic monomers, urethane acrylate resins, polyester acrylate resins, and epoxy acrylate resins. It is done.
In addition, if the raw material monomer of the transparent resin is in a liquid state and the raw material monomer conforms to the conditions of the transparent resin forming paint shown above, the transparent resin raw material monomer itself should be used as the transparent resin forming paint. Is also possible.

The transparent resin layer 15 may contain inorganic oxide fine particles, silicon alkoxide, hydrolyzate of metal alkoxide, and the like as necessary.
Examples of the inorganic oxide fine particles include silica, alumina, zinc oxide, zirconia, titania and the like.
Examples of the hydrolyzate of silicon alkoxide or metal alkoxide include those having one or more organic functional groups selected from the group of vinyl group, epoxy group, acryloxy group, methacryloxy group, and isocyanate group.
By containing inorganic oxide fine particles, silicon alkoxide, or metal alkoxide hydrolyzate, the adhesion with the transparent conductive film 16 laminated on the transparent resin layer 15 is improved, and the transparent resin layer 15 and the transparent resin layer 15 are transparent. Reflection of external light caused by a difference in refractive index from the conductive film 16 can be reduced.

The transparent conductive film 16 is provided so as to cover the thin metal wire layer 34 and the entire transparent resin layer 15.
The material constituting the transparent conductive film 16 may be any transparent conductive material that can be formed at a temperature lower than the heat resistant temperature of the resin film constituting the transparent substrate 11. For example, tin-doped indium oxide (Indium Tin Oxide) Metal oxides such as Oxide (ITO), aluminum-doped zinc oxide (AZO), gallium-zinc oxide (GZO), and indium-zinc composite oxide (IZO), Examples thereof include conductive polymers such as polythiophenes, polypyrroles, and polyanilines. In particular, ITO is suitable because it is excellent in transparency and conductivity.

The thickness of the transparent conductive film 16 varies depending on the type and specification of the transparent conductive material and is not particularly limited. For example, when using ITO, the thickness is preferably 10 to 250 nm, more preferably 30 to 30 nm. 150 nm.
Here, when the thickness exceeds 250 nm, the light transmittance is remarkably lowered, and cracks are easily generated when the transparent substrate is bent. On the other hand, when the thickness is less than 10 nm, it is difficult to sufficiently impart conductivity to the opening 17, which causes inconvenience when used as an electrode of a solar cell or an organic EL element.

Next, the manufacturing method of the low resistance transparent conductive film of this embodiment is demonstrated.
Here, when the catalyst ink layer 32 is formed on the flexible transparent substrate 11, the primer layer 12 is used as a base layer of the catalyst ink layer 32 in order to improve the accuracy of the print pattern of the catalyst ink layer 32. It is preferable to provide it.

"Formation of primer layer"
The primer layer 12 is formed by applying the primer layer-forming coating material on the transparent substrate 11 by a gravure printing method, a bar coating method, an offset printing method, or the like, and then drying.
As the primer layer forming coating, a coating containing oxide fine particles, an organic polymer, and an organic solvent is preferably used.
Examples of the oxide fine particles include metal oxides such as alumina, titania and zirconia, and inorganic oxides such as silica. These two or more may be used in combination.

  As the organic polymer, any resin having resistance to a plating bath when the metal layer 33 is formed, for example, a resin having a heat resistant temperature of 120 to 150 ° C. and excellent chemical resistance can be used. Examples of such resins include cellulose derivatives such as ethyl cellulose and propyl cellulose, polyvinyl butyral, acrylic resins, polyurethane resins, rosin ester resins, and the like, and two or more of these may be used in combination.

The ratio (M / R) of the oxide fine particles (M) to the organic polymer (R) in the primer layer forming coating is preferably 90/10 to 10/90, more preferably 60/40 to 40/60.
When the ratio of the oxide fine particles is higher than the above range, the adhesion strength of the formed primer layer 12 with the transparent base material 11 becomes weak, the light transmittance of the obtained transparent conductive film 1 itself decreases, and haze On the other hand, if the ratio is lower than the above range, the effect as a receiving layer when the catalyst ink layer 32 is formed by the printing method is small, and the pattern reproducibility of the printed catalyst ink layer 32 is poor. This is because there is a possibility of becoming.

The organic solvent is not particularly limited as long as it can disperse fine oxide particles and can dissolve the organic polymer. For example, aromatic hydrocarbons such as toluene and xylene, and cyclic aliphatic hydrocarbons such as cyclohexanone. , Ketones such as methyl ethyl ketone, and alcohols such as 2-propanol are preferably used, and a mixture of two or more of these may be used.
A dispersant such as a phosphate ester may be added to the organic solvent for the purpose of improving the dispersibility of the oxide fine particles.

  The thickness of the obtained primer layer 12 is preferably 0.5 to 5.0 μm, more preferably 1.0 to 3.0 μm. Here, if the thickness of the primer layer 12 is thinner than the above range, the effect as a receiving layer when the catalyst ink layer 32 is formed by the printing method is reduced. On the other hand, if the thickness is thicker than the above range, This is because there is a possibility of adversely affecting optical characteristics such as light transmittance and haze.

"Catalyst ink layer formation"
The catalyst ink layer 32 is formed by applying the catalyst ink in a predetermined pattern on the primer layer 12 of the transparent base material 11 by a printing method and then drying it.
As this catalyst ink, an ink containing oxide fine particles carrying noble metal fine particles, an organic polymer, and an organic solvent is preferably used.
The oxide fine particles supporting the noble metal fine particles enhance the catalytic activity of the noble metal by supporting the noble metal fine particles on the oxide fine particles, in addition to the thixotropy of the catalyst ink suitable for printing and the effect of obtaining a good printing shape. An effect is obtained.

Examples of the noble metal fine particles include fine particles of gold, platinum, palladium, ruthenium, rhodium, iridium, osmium and the like. Two or more kinds of these noble metal fine particles may be mixed and used.
The content of the noble metal fine particles is preferably 0.01% by mass or more and 1.5% by mass or less, more preferably 0.10% by mass or more and 0.50% by mass or less.
Here, if the content of the noble metal fine particles is less than 0.01% by mass, it does not function as a catalyst for electroless plating. On the other hand, if the content exceeds 1.5% by mass, an expensive noble metal is used more than necessary. This is a cause of cost increase.

Examples of the oxide fine particles supporting the noble metal fine particles include metal oxide fine particles such as alumina, zinc oxide, zirconia, and titania. Two or more kinds of these metal oxide fine particles may be mixed and used.
The content of the oxide fine particles is preferably 3.0% by mass or more and 27.0% by mass or less, more preferably 13.0% by mass or more and 20.0% by mass or less.
Here, when the content of the oxide fine particles is less than 3.0% by mass, the viscosity of the catalyst ink is low and the thixotropy is lost. On the other hand, if it exceeds 27.0% by mass, the viscosity of the catalyst ink is increased, so that the fluidity is lowered, resulting in poor transfer and adhesion of ink to the opening. As a result, the reproducibility of the print pattern is lowered.

The ratio (N / M) of the noble metal fine particles (N) to the oxide fine particles (M) in the oxide fine particles supporting the noble metal fine particles is preferably 0.5 / 99.5 to 5/95 by mass ratio, More preferably, it is 1/99 to 2/98.
Here, if the ratio of the noble metal fine particles is lower than the above range, it does not function as a catalyst for electroless plating. On the other hand, if it is higher than the above range, the function as a catalyst for electroless plating is saturated. This is because a precious metal that is more expensive than necessary is used, which causes an increase in cost.

  The organic polymer may be any resin that has printing suitability such as pattern reproducibility and is resistant to the plating solution used to form the metal layer 33. Ethyl cellulose, rosin ester resin, acrylic resin, polyvinyl butyral Examples thereof include resins and polyurethane resins. Two or more kinds of these resins may be mixed and used. Among them, ethyl cellulose is preferable because appropriate rheological properties can be obtained in a printing method such as gravure printing.

The content of the organic polymer is preferably 1.0% by mass or more and 15.0% by mass or less, more preferably 6.0% by mass or more and 10.0% by mass or less.
Here, when the content of the organic polymer is less than 1.0% by mass, the viscosity of the ink becomes too low and is not suitable for printing. On the other hand, when the content exceeds 15.0% by mass, the ink This is because the viscosity of the ink becomes too high and is not suitable for printing.

The ratio (NM / R) of the oxide fine particles (NM) supporting the noble metal fine particles to the organic polymer (R) is preferably 40/60 to 80/20, more preferably 60/40. ~ 70/30.
Here, if the ratio of the oxide fine particles supporting the noble metal fine particles is lower than the above range, the contained noble metal fine particles are almost covered with the polymer resin, so that it does not function as a catalyst for electroless plating. On the other hand, if the ratio is higher than the above range, the printability deteriorates, and the printed film is not sufficiently cured by the polymer resin, and the adhesion to the transparent substrate 11 on which the primer layer 12 is formed is poor. This is because it cannot be obtained.

  The organic solvent is not particularly limited as long as it can disperse oxide fine particles carrying precious metal fine particles and can dissolve organic polymers. For example, toluene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, Examples include cyclohexanone, ethylene glycol, butyl carbitol, butyl carbitol acetate, α-terpineol, isophorone, N-methylpyrrolidone, and the like.

The viscosity of the catalyst ink is preferably 1 to 500 Pa · s, more preferably 50 to 200 Pa · s.
Here, when the viscosity of the catalyst ink is less than 1 Pa · s, the thixotropy of the ink is lost, and defects such as stringing occur and a good printed shape cannot be obtained. On the other hand, it exceeds 500 Pa · s. This is because the ink cannot be supplied uniformly during printing and printing unevenness occurs.

In the fine metal wire layer, when it is necessary to color a pattern, improve contrast, reduce reflection, etc., various pigments such as carbon black may be added to the catalyst ink.
The content of the pigment is not particularly limited as long as an amount necessary for coloring the pattern is added, but it is preferably kept at 5.0% by mass or less. This is because if the pigment content exceeds 5.0% by mass, it becomes difficult to adjust the viscosity of the ink to be appropriate for various printings depending on the oil absorption amount of the pigment, which may adversely affect the printability.

Formation of the catalyst ink layer 32 on the primer layer 12 of the transparent substrate 11 can be performed using various printing methods such as a gravure printing method, a screen printing method, and a flexographic printing method. Among these, the gravure printing method is a preferable method because it can form a thin line pattern continuously by a roll-to-roll method, is easy to manufacture in a large area, and is excellent in productivity.
In the gravure printing method, the catalyst ink is supplied to the plate-making on which the network pattern is formed, and then the catalyst ink on the plate-making is transferred onto the primer layer 12 of the transparent substrate 11, and then the transferred catalyst ink is transferred to the plate-making. The catalyst ink layer 32 having a predetermined pattern can be formed by drying using a dryer or the like.
The drying temperature at this time is preferably 150 ° C. or less in consideration of the heat resistance of the transparent substrate 11.

As described above, the catalyst ink layer 32 having a predetermined pattern can be formed on the primer layer 12 of the transparent substrate 11.
In addition, when the accuracy of the print pattern of the catalyst ink layer 32 is not so required, the catalyst ink layer 32 may be formed directly on the transparent substrate 11.

"Formation of metal layer"
The transparent substrate 11 on which the catalyst ink layer 32 having a predetermined pattern is formed is immersed in an electroless plating bath, and a metal is deposited on the catalyst ink layer 32 to form the metal layer 33.
When it is necessary to further reduce the resistance of the metal layer 33, after forming the metal layer 33, a metal made of copper, nickel, or the like is deposited on the metal layer 33 by electroplating. A metal layer having a two-layer structure or a multilayer structure of three or more layers may be used.

In order to improve the corrosion resistance of the metal layer 33, the metal layer 33 may be covered with a metal having good corrosion resistance such as nickel. Examples of the method for coating a metal having good corrosion resistance include electroplating, electroless plating, chemical conversion treatment, etc., for example, nickel electroplating, nickel-tungsten alloy electroplating, platinum displacement plating, chromate (chromic acid). Processing and the like.
Further, instead of coating the metal for improving the corrosion resistance, the surface of the metal layer 33 is formed by using a paint in which conductive carbon black is dispersed in an electrodeposition resin or a paint in which a conductive polymer is dissolved or dispersed. Corrosion resistance can also be improved by electrodeposition coating.
As described above, the network-like fine metal wire layer 34 including the catalyst ink layer 32 and the metal layer 33 can be formed on the primer layer 12 of the transparent substrate 11.

"Formation of transparent resin layer"
The transparent resin layer 15 is formed by applying a coating for forming a transparent resin layer so as to cover the mesh of the fine metal wire layer 34 and its peripheral edge, that is, the opening 17 and its peripheral edge, and then drying or curing. To do.
As the transparent resin layer-forming coating material, a coating material containing a transparent resin and an organic solvent that dissolves the transparent resin is preferably used.

  The transparent resin is not particularly limited as long as it is transparent to visible light. For example, acrylic resins, polyester resins, polyurethane resins, cellulose derivatives and other thermoplastic resins, phenol resins, urea resins, Examples thereof include thermosetting resins such as melamine resins, polyurethane resins, epoxy resins, and polysiloxane resins, and ultraviolet curable resins such as acrylic monomers, methacrylic monomers, urethane acrylate resins, polyester acrylate resins, and epoxy acrylate resins.

  Among these transparent resins, in particular, if an ultraviolet curable resin such as an acrylate resin is used, it can be cured in a short time, and it is excellent in productivity and the mechanical strength of the formed transparent resin layer is also high. This is preferable.

The content of the transparent resin in the coating for forming a transparent resin layer is not particularly limited, but is preferably 1.0% by mass or more and 90.0% by mass or less, more preferably 5.0% by mass. It is above and 50.0 mass% or less.
Here, if the content of the transparent resin is less than 1.0% by mass, a large amount of paint is required to reduce the level difference (unevenness) between the fine metal wire layer 34 and the opening 17, and during coating, It is necessary to increase the wet film thickness (film thickness before drying), which is a film thickness. In this case, since there are many volatile components in the coating film, unevenness occurs during drying, resulting in a homogeneous film. The body may not be obtained. On the other hand, if the content of the transparent resin exceeds 90.0% by mass, it is difficult to adjust the film thickness so that the transparent resin layer is formed only on the opening 16 of the fine metal wire layer 34 depending on the coating conditions. Depending on the case, the thin metal wire layer 34 may be completely covered with the transparent resin, and as a result, the thin metal wire layer 34 and the transparent conductive film 15 may not be electrically connected, resulting in an insulating state.

  The organic solvent is not particularly limited as long as it dissolves the transparent resin, and examples thereof include aliphatic hydrocarbons such as hexane, aromatic hydrocarbons such as toluene, and cyclic aliphatic carbonization such as cyclohexanone. Hydrogen, ketones such as methyl ethyl ketone and methyl isobutyl ketone, acetates such as ethyl acetate, and alcohols such as ethanol and 2-propanol are preferably used. Two or more kinds of these organic solvents may be mixed and used.

  The coating material for forming a transparent resin layer has a boiling point of 120 in order to prevent the transparent resin from remaining in the vicinity of the highest portion (top portion) of the fine metal wire layer 34 due to rapid drying of the solvent during coating. It is preferable to contain at least one organic solvent having a temperature of at least ° C. Examples of the organic solvent having a boiling point of 120 ° C. or higher include xylene, cyclohexanone, diisobutyl ketone, butyl acetate, and 2-ethoxyethanol.

The transparent resin layer-forming coating material may contain inorganic oxide fine particles, silicon alkoxide, metal alkoxide hydrolyzate, and the like, if necessary.
Examples of the inorganic oxide fine particles include silica, alumina, zinc oxide, zirconia, titania and the like.
Examples of the hydrolyzate of silicon alkoxide or metal alkoxide include those having one or more organic functional groups selected from the group of vinyl group, epoxy group, acryloxy group, methacryloxy group, and isocyanate group.

When the coating for forming the transparent resin layer contains inorganic oxide fine particles, silicon alkoxide, hydrolyzate of metal alkoxide, etc., the adhesion with the transparent conductive film 16 laminated on the transparent resin layer 15 is improved. The reflection of external light caused by the difference in refractive index between the transparent resin layer 15 and the transparent conductive film 16 can be reduced.
Furthermore, when the transparent resin layer-forming coating material contains a filler such as inorganic oxide fine particles, a dispersant or the like may be added to facilitate the dispersion of the filler.

The surface tension of the paint for forming a transparent resin layer is not particularly limited, but is preferably 35 N / m or less, and more preferably 25 N / m or less.
Here, when the surface tension of the coating for forming the transparent resin layer exceeds 35 N / m, the wettability with the fine metal wire layer 34 deteriorates, and the peripheral edge of the opening 17 of the fine metal wire layer 34, that is, the fine metal wire 35. It becomes difficult to form the transparent resin layer 15 so as to have a gentle forward taper-shaped portion 21 from the portion having a shape with a reduced thickness in the cross-sectional direction into the opening 17.

  Thus, when the smooth forward taper shape part 21 from the part which has the shape where the thickness of the cross-sectional direction of the metal fine wire 35 reduces to the opening part 17 is not obtained, when the transparent conductive film 16 mentioned later was laminated | stacked In addition, there is a possibility that a uniform and good transparent conductive film 16 cannot be obtained due to film formation defects or cracks. Therefore, when the surface tension of the coating material for forming the transparent resin layer exceeds 35 N / m, an appropriate amount of a surface conditioner such as a leveling agent is necessary to adjust the wettability with the fine metal wire layer 34. It is preferable to add.

  The viscosity of the coating material for forming the transparent resin layer is not particularly limited, but is preferably 500 mPa · s or less. Here, if the viscosity is higher than 500 mPa · s, unevenness of the film thickness is likely to occur when the transparent resin layer forming coating is applied on the transparent base material 11 on which the thin metal wire layer 34 is formed. In addition to causing defects in appearance, the fluidity of the paint is poor, and the fine metal wire layer 34 is partially covered with the transparent resin layer 15, so that a good gap between the fine metal wire layer 34 and the transparent conductive film 16 is obtained. There is a risk that the electrical connection may be lost.

As a method for applying the transparent resin layer-forming coating material, the transparent resin layer-forming coating material is applied on the transparent base material 11 on which the fine metal wire layer 34 is formed by a gravure printing method, a bar coating method, an offset printing method, or the like. After coating and then drying to dissipate the solvent, UV coating, heat treatment (annealing), etc. are applied as necessary to cure the coating.
The wet film thickness (the film thickness of the coating film before curing) during coating depends on the amount of the transparent resin contained in the transparent resin layer-forming coating material, and is not particularly limited. The maximum thickness is preferably 0.5 times or more and 5 times or less. For example, when the content of the transparent resin in the paint is 10% by mass, the wet film thickness is preferably 5 to 40 μm. By performing the coating so that the wet film thickness is in the above range, the peripheral portion of the opening 17, that is, the portion having a shape in which the thickness in the cross-sectional direction of the metal thin wire 35 is reduced, and gradually into the opening 17. Since the transparent resin layer 15 which has the forward taper-shaped part 21 can be formed, it is preferable.

  The transparent resin layer 15 thus obtained has an average thickness that is thinner than the maximum thickness of the fine metal wire layer 34 and a thickness at the center that is thinner than the thickness at the outer periphery. Specifically, in the peripheral part of the metal fine wire layer 34, 0.5-6.0 micrometers is preferable, More preferably, it is 1.0-3.0 micrometers. In the vicinity of the center of the opening 17, it is preferably 0.3 to 4.0 μm. If the thickness of the transparent resin layer 15 is smaller than the above range, the step (unevenness) between the peripheral edge portion of the metal thin wire layer 34 and the opening portion 17 is made sufficiently small to form a good transparent conductive film 16. I can't. On the other hand, if the thickness of the transparent resin layer 15 is thicker than the above range, the fine metal wire layer 34 is covered with the transparent resin, and as a result, the electric current between the vicinity of the highest portion of the fine metal wire layer 34 and the transparent conductive film 16 is increased. Connection may be poor, and the low-resistance transparent conductive film 31 may not be obtained.

"Formation of transparent conductive film"
A transparent conductive film 16 is formed on the thin metal wire layer 34 and the transparent resin layer 15 by sputtering, ion plating, CVD, plasma CVD, vapor deposition, wet coating, or the like.
The method for forming the transparent conductive film 16 is not particularly limited, but a roll-to-roll method can be applied as long as it is a sputtering method, and a metal oxide such as ITO, AZO, GZO, or IZO is applied to the transparent substrate 11. Therefore, it can be used preferably because it can be continuously and easily performed.

The film thickness of the transparent conductive film 16 may be adjusted in accordance with the required conductivity. For example, when ITO is used as the transparent conductive film, light transmission is achieved while providing sufficient conductivity to the opening 17. In order to increase the rate, it is preferable to form the transparent conductive film 16 so that the thickness is in the range of 10 to 250 nm.
As described above, a low-resistance transparent conductive film having high transparency and low surface resistance can be produced by an inexpensive manufacturing process.

[Third Embodiment]
FIG. 5 is a partially enlarged cross-sectional view showing a low resistance transparent conductive film 41 according to the third embodiment of the present invention. This low resistance transparent conductive film 41 is the low resistance transparent conductive film 31 according to the second embodiment. Unlike the low resistance transparent conductive film 31 of the second embodiment, the thin metal wire 35 has a laminated structure of the catalyst ink layer 32 and the metal layer 33, thereby forming the thin metal wire layer 34. In the low resistance transparent conductive film 41 of the present embodiment, the thin metal wire 43 has a laminated structure of the conductive ink layer 42 and the metal layer 33, thereby forming the thin metal wire layer 44. Is exactly the same as the low-resistance transparent conductive film 31 of the second embodiment.

The conductive ink layer 42 can be formed by applying a conductive ink containing conductive powder, an organic polymer, and an organic solvent, and then drying or curing.
As this conductive powder, metal powder such as silver powder, copper powder and nickel powder can be used. In particular, silver powder is preferably used from the viewpoint of reliability such as conductivity and oxidation resistance of the powder itself. It is done.

The particle size of these metal powders is not particularly limited, but is preferably 0.1 to 5 μm. Here, when the average particle diameter of the metal powder is less than 0.1 μm, the dispersibility in the conductive ink is lowered, and it becomes easy to form an aggregate. When drying at a low temperature such as the heat resistant temperature or lower, the conductivity of the obtained conductive ink layer 42 may be deteriorated. On the other hand, if the average particle size of the metal powder exceeds 5 μm, it is difficult to form a fine pattern, the surface of the conductive ink layer 42 is uneven, and the like, and the metal layer 33 is good. May not be able to be formed properly.
The shape of the metal powder is not particularly limited, and may be appropriately used according to the purpose of use and product specifications such as granular, true spherical, flake, and needle. Two or more kinds of these metal powders may be mixed and used.

  In order for this conductive ink to exhibit good conductivity, the content of the metal powder is preferably adjusted to 50 to 85% by mass of the entire conductive ink. Here, if the content of the metal powder is less than the above range, it becomes difficult to develop sufficient conductivity. On the other hand, if the content exceeds the above range, the viscosity after the ink is too high. Therefore, patterning by a printing method becomes difficult.

  The organic polymer is not particularly limited, and examples thereof include cellulose derivatives such as ethyl cellulose, polyester resins, acrylic resins, polyvinyl butyral resins, polyurethane resins, polyamide resins, epoxy resins, melamine resins, and phenol resins. It is done. Two or more kinds of these resins may be mixed and used.

The ratio (SP / R) of the metal powder (SP) to the organic polymer (R) is preferably 70/30 to 98/2, more preferably 85/15 to 95/5 in terms of mass ratio.
Here, when the ratio of the metal powder is lower than the above range, the metal powder is almost covered with the organic polymer, and sufficient conductivity cannot be obtained. Since the number of molecules is too small, the printability is deteriorated, and when the conductive ink layer is formed, the curing becomes insufficient, and the adhesion to the transparent substrate 11 and the primer layer 12 cannot be obtained.

  The organic solvent contained in the conductive ink is not particularly limited as long as it disperses metal powder and dissolves the organic polymer. Examples thereof include methyl carbitol, butyl carbitol acetoate, benzyl alcohol, terpineol, and N-methyl. Formamide, N-methylacetamide, N-methylpyrrolidone, γ-butyrolactone, dimethyl sulfoxide, 2-hydroxyethyl acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, ethyl acetate, butyl acetate, methanol, ethanol, 2 -Propanol, ethylene glycol, water and the like. These organic solvents may be used as a mixture of two or more.

  In this conductive ink, the content of the organic solvent is preferably in the range of 10 to 50 parts by mass with respect to 100 parts by mass of the conductive powder. When the content of the organic solvent is less than 10 parts by mass, it is difficult to adjust the viscosity of the conductive ink, and it becomes difficult to obtain good printing characteristics. On the other hand, when the content of the organic solvent exceeds 50 parts by mass, it is difficult to sufficiently dry after printing the conductive ink, and the obtained pattern may not be able to exhibit sufficient conductivity.

This conductive ink preferably contains a rheology control agent in order to impart rheological properties suitable for printing. Examples of the rheology control agent include oil-absorbing fine particles such as alumina and silica, aliphatic amide compounds such as stearic acid amide, fatty acid esters such as stearic acid ester, fatty acids such as castor oil, gelatin, thickening polysaccharides Polymer compounds such as acrylic polymers, metal soaps such as aluminum stearate and calcium stearate, clay minerals such as synthetic smectite and organic bentonite can be suitably used.
Moreover, you may add additives, such as a dispersing agent, a leveling agent, and an antifoamer, to this electroconductive ink as needed.

As in the case of the catalyst ink layer 32 of the second embodiment, the conductive ink layer 42 is formed by using a conductive ink containing conductive powder, an organic polymer, and an organic solvent by a gravure printing method or a screen printing method. It can be formed by coating using various printing methods such as flexographic printing, and then drying the conductive ink using a dryer or the like.
The drying temperature at this time is preferably 150 ° C. or less in consideration of the heat resistance of the transparent substrate 11.

As described above, the conductive ink layer 42 having a predetermined pattern can be formed on the primer layer 12 of the transparent substrate 11.
By forming the metal layer 33 on the conductive ink layer 42 thus obtained by electroless plating or electrolytic plating, the conductive ink layer 42 and the primer layer 12 of the transparent substrate 11 are formed. A network-like fine metal wire layer 44 made of the metal layer 33 can be formed.
In addition, when the accuracy of the print pattern of the conductive ink layer 42 is not so required, the conductive ink layer 42 may be formed directly on the transparent substrate 11.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.

[Example 1]
"Preparation of primer layer forming paint and formation of primer layer"
240 g of alumina powder and 28 g of a phosphoric acid ester dispersant were added to 1332 g of toluene and dispersed using a sand mill to prepare an alumina dispersion.
Next, 240 g of ethyl cellulose was dissolved in 1808 g of toluene, and the above-mentioned alumina dispersion, 552 g of cyclohexanone, and 1800 g of methyl ethyl ketone were added to the obtained solution, and mixed with a homogenizer to prepare a primer layer forming coating material.
Next, this primer layer-forming coating material was coated on a polyethylene terephthalate (PET) film having a thickness of 125 μm by a microgravure printing method, and then dried to obtain a transparent film having a primer layer formed on the surface. The obtained primer layer had a thickness of 2 μm.

"Preparation of catalyst ink and formation of catalyst ink layer"
3.5 g of palladium fine particles and 171.5 g of γ-alumina were dispersed and agglomerated in ethanol, solid-liquid separated and then dried to obtain γ-alumina fine particles supporting the palladium fine particles.
Next, 90 g of ethyl cellulose was dissolved in a solution consisting of 472 g of α-terpineol and 236 g of butyl carbitol acetate, and γ-alumina fine particles supporting the above-mentioned palladium fine particles and 9 g of carbon black were added and mixed in a three-roll mill. Dispersed to prepare a catalyst ink.
Next, a mesh pattern of L / P = 18/290 μm was printed on the primer layer of the transparent film by a gravure printing method at a printing speed of 12 m / min, and then 5 ° C. at 80 ° C. The film was dried for a minute to obtain a transparent film with a mesh on which a mesh-like catalyst ink layer having a thickness of 1.2 μm was formed. The shape of the obtained mesh pattern was very good, and there was no problem in appearance.

"Formation of metal layers and fine metal wire layers"
The above transparent film with mesh is immersed in an electroless copper plating solution OPC-750 (produced by Okuno Pharmaceutical Co., Ltd.) at 25 ° C. for 40 minutes to deposit copper on the mesh-like catalyst ink layer, and the thickness is 2.0 μm. The metal layer was formed. Thereafter, nickel plating was applied to the metal layer to produce a mesh-like fine metal wire layer.
The network pattern of the fine metal wire layer has a line width (L) of 20 μm and a pitch (P) of 290 μm. The height (T) and line width (L) of the highest portion (top surface) of the fine metal wire layer. The ratio (T / L) was 0.19, the surface resistance was 0.2Ω / mouth, the visible light transmittance was 84%, and the haze value was 3%.

"Formation of transparent resin layer"
Polyurethane acrylate resin EBCRYL8210 (manufactured by Daicel-Cytec) 480g
Pentaerythritol triacrylate 120g
Methyl ethyl ketone 2440g
Methyl isobutyl ketone 2000g
900g diisobutylketone
Photoinitiator Irgacure 184 (Ciba Specialty Chemicals)
30g
Leveling agent BYK-380N (by Big Chemie) 30g
Were mixed to prepare a paint for forming a transparent resin layer.

  Next, this transparent resin layer-forming coating material was applied on the transparent film on which the network-like fine metal wire layer was formed by microgravure printing so that the wet film thickness was 24 μm at a speed of 30 m / min. A transparent resin layer was formed by drying at 120 ° C. and further curing by irradiation with ultraviolet rays. The obtained transparent resin layer was formed in the peripheral part of the opening part of the metal fine wire layer and in the opening part, and had a gently tapered shape, and the film thickness in the vicinity of the center of the opening part was 1.5 μm.

"Formation of transparent conductive film"
A transparent conductive film (ITO film) was formed on the transparent film on which the fine metal wire layer and the transparent resin layer were formed by sputtering in an inert gas atmosphere using ITO (tin-doped indium oxide) as a target. The thickness of the obtained ITO film was 120 nm.
Thus, the low resistance transparent conductive film of Example 1 was produced.

"Evaluation of transparent conductive film"
Table 1 shows the evaluation results of the low-resistance transparent conductive film of Example 1. Evaluation items and evaluation methods are as follows.
(1) Surface resistance Measured in accordance with Japanese Industrial Standard JIS K 7194 “Resistivity Test Method for Conductive Plastics Using 4-Probe Method”.
(2) Transmittance and haze The transmittance and haze were measured in accordance with Japanese Industrial Standard JIS K 7105 “Testing Method for Optical Properties of Plastics”.
(3) Corrosion resistance The transparent conductive film was immersed in a 1.5% iodine solution (solvent: acetonitrile) for 1 month, and then taken out. The corrosion resistance of the thin metal wire layer was evaluated according to the following criteria.
○: There was no corrosion of the thin metal wire layer.
Δ: Slight corrosion occurred in the thin metal wire layer.
X: The fine metal wire layer was significantly corroded and dissolved.

[Example 2]
A transparent film with a mesh on which a mesh-like catalyst ink layer was formed was produced in the same manner as in Example 1. The pattern shape of the transparent film with mesh was very good, and there was no problem in appearance.
Next, the transparent film with mesh is immersed in an electroless copper plating solution OPC-750 (Okuno Pharmaceutical Co., Ltd.) at 25 ° C. for 10 minutes to deposit copper on the mesh-like catalyst ink layer, and the thickness is 1. A first metal layer having a thickness of 0.0 μm was formed.

Next, the copper-deposited transparent film with a mesh was subjected to an electrolytic copper plating treatment at a current density of 3 A / dm 2 at 25 ° C. for 5 minutes using an electrolytic copper plating solution TOPLUTINA SF (Okuno Pharmaceutical Co., Ltd.). A second metal layer having a thickness of 3.0 μm was formed.
Next, nickel plating was performed on the second metal layer by electroplating to obtain a fine metal wire layer in which copper and nickel were laminated in three layers.
The network pattern of the fine metal wire layer has a line width (L) of 22 μm and a pitch (P) of 290 μm. The height (T) and line width (L) of the highest portion (top surface) of the fine metal wire layer. The ratio (T / L) was 0.31, the surface resistance was 0.05Ω / mouth, the visible light transmittance was 81%, and the haze value was 3%.

Next, a transparent resin layer and a transparent conductive film were formed in the same manner as in Example 1, and a low resistance transparent conductive film of Example 2 was produced.
The low resistance transparent conductive film of Example 2 was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

[Example 3]
In the same manner as in Example 2, a transparent film on which a fine metal wire layer in which copper and nickel were laminated in three layers was formed.
Then
Polyurethane acrylate resin EBCRYL8210 (manufactured by Daicel-Cytec) 720g
200 g of tripropylene glycol diacrylate
280 g of hydroxypropyl acrylate
Methyl ethyl ketone 2310g
Methyl isobutyl ketone 1500g
900g diisobutylketone
Photoinitiator Irgacure 184 (Ciba Specialty Chemicals)
60g
Leveling agent BYK-380N (by Big Chemie) 30g
Were mixed to prepare the transparent resin layer-forming coating material of Example 3.

Next, a transparent resin layer was formed in the same manner as in Example 1 by using this transparent resin layer forming paint.
The obtained transparent resin layer was formed in the peripheral part of the opening part of the metal fine wire layer and in the opening part, and had a gentle taper shape, and the film thickness in the vicinity of the center of the opening part was 3.6 μm.
Next, a transparent conductive film was formed in the same manner as in Example 1, and a low resistance transparent conductive film of Example 3 was produced.
The low resistance transparent conductive film of Example 3 was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

[Example 4]
After dissolving 120 g of ethyl cellulose in 290 g of terpineol and 290 g of N-methylpyrrolidone, 2100 g of silver powder AG2-1C (average particle size: 1.0 μm, manufactured by DOWA Electronics) and fatty acid amide compound Disparon F-9020 (manufactured by Enomoto Kasei) 200 g was added and mixed and dispersed in a three-roll mill to prepare a conductive ink of Example 4.
Next, a mesh pattern of L / P = 18/290 μm was printed by this gravure printing method on the primer layer of the transparent film produced in the same manner as in Example 1, and then 5 ° C. at 150 ° C. The film was dried for 5 minutes to obtain a transparent film with mesh on which a mesh-like conductive ink layer having a thickness of 2.5 μm was formed. The shape of the obtained mesh pattern was very good, and there was no problem in appearance.

Next, the transparent film with mesh is subjected to an electrolytic copper plating treatment at a current density of 3 A / dm 2 for 5 minutes at 25 ° C. using an electrolytic copper plating solution Top Lucina SF (manufactured by Okuno Pharmaceutical Co., Ltd.). A metal layer of 0.0 μm was formed.
Next, this metal layer was subjected to nickel plating by electroplating to produce a thin metal wire layer.
The network pattern of the fine metal wire layer has a line width (L) of 22 μm and a pitch (P) of 290 μm. The height (T) and line width (L) of the highest portion (top surface) of the fine metal wire layer. The ratio (T / L) was 0.30, the surface resistance was 0.05Ω / mouth, the visible light transmittance was 81%, and the haze value was 3%.

Next, a transparent resin layer was formed in the same manner as in Example 1 using the transparent resin layer forming coating material of Example 3.
The obtained transparent resin layer was formed in the peripheral part of the opening part of the metal fine wire layer and in the opening part, and had a gentle taper shape, and the film thickness in the vicinity of the center of the opening part was 3.6 μm.
Next, a transparent conductive film was formed in the same manner as in Example 1, and a low resistance transparent conductive film of Example 4 was produced.
The low resistance transparent conductive film of Example 4 was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

[Comparative Example 1]
In the same manner as in Example 1, a mesh-like fine metal wire layer was produced on a transparent film with a mesh.
Next, a transparent conductive film (ITO film) was formed on the transparent film with a mesh on which the mesh-like fine metal wire layer was formed without forming a transparent resin layer in the same manner as in Example 1. Comparative Example 1 transparent conductive film was produced.
The transparent conductive film of Comparative Example 1 was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

[Comparative Example 2]
In the same manner as in Example 1, a mesh-like fine metal wire layer was produced on a transparent film with a mesh.
Next, the transparent resin layer-forming coating material of Example 3 is applied to the transparent film with mesh on which the network-like fine metal wire layer is formed so that the wet film thickness becomes 60 μm at a speed of 30 m / min by microgravure printing. Then, it was dried at 120 ° C. and then cured by irradiation with ultraviolet rays to form a transparent resin layer.
The obtained transparent resin layer completely covered the thin metal wire layer, and the film thickness in the vicinity of the center of the opening was 10 μm.
Next, a transparent conductive film was formed in the same manner as in Example 1, and a transparent conductive film of Comparative Example 2 was produced.
The transparent conductive film of Comparative Example 2 was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

  The transparent conductive films of Examples 1 to 4 have a low surface resistance value of 0.2Ω / □ or less, a transmittance of 72% or more, a haze value of 4.0% or less, and a good transparency. Yes, it had good characteristics as a low resistance transparent conductive film.

On the other hand, in Comparative Example 1, the corrosion resistance was poor, the fine metal wire layer after the corrosion test was significantly corroded and dissolved, and the resistance value of the film was also greatly increased. This is because the transparent resin layer is not provided, so that film formation defects such as insufficient film thickness and cracks occur in the transparent conductive film. It is thought that it penetrated into the film and corroded the fine metal wire layer.
In Comparative Example 2, since the transparent resin layer completely covers the fine metal wire layer, the transparent conductive film and the fine metal wire layer cannot be in contact with each other, and as a result, electrical connection between the transparent conductive film and the fine metal wire layer is achieved. Since it became defective, it is thought that the electrical resistance value of a transparent conductive film is high.

  Since the present invention was able to realize a transparent conductive film having excellent light transmittance and a very low surface resistance value by a method with excellent productivity, a dye-sensitized solar cell, etc. The present invention can be applied not only to a solar power generation apparatus, but also to an electroluminescence element, various display devices, and the like, and its industrial value is extremely large.

1 Low Resistance Transparent Conductive Film 11 Flexible Transparent Substrate 12 Primer Layer (Underlayer)
13 Metal fine wire 14 Mesh-like metal fine wire layer 15 Transparent resin layer 16 Transparent conductive film 17 Opening 18 Edge of metal fine wire 19 End of transparent resin layer (contact portion of transparent resin layer surface and metal fine wire surface)
20 Edge of fine metal wire (embedded in transparent resin layer)
21 forward tapered portion 31 low resistance transparent conductive film 32 catalyst ink layer (network layer having catalytic properties)
33 Metal layer 34 Mesh-like fine metal wire layer 35 Metal fine wire 41 Low resistance transparent conductive film 42 Conductive ink layer 43 Metal fine wire 44 Mesh-like fine metal wire layer

Claims (6)

A transparent base material having flexibility, a metal fine wire layer formed on the transparent base material and formed of a fine metal wire in a mesh shape, and provided so as to cover the inside of the mesh of the fine metal wire layer and its peripheral portion. A transparent resin layer, and a transparent conductive film provided so as to cover the fine metal wire layer and the transparent resin layer ,
The thin metal wire has a partial cross-sectional shape that is arcuate in the cross-sectional direction or is inclined with respect to the transparent base material, so that the thickness in the cross-sectional direction decreases toward the outside. And
The end of the transparent resin layer is in contact with the portion where the thickness in the cross-sectional direction of the thin metal wire is reduced,
Low resistance transparent, characterized in that an angle (θ) formed between the tangent of the surface of the transparent resin layer and the tangent of the surface of the thin metal wire satisfies 120 ° ≦ θ ≦ 180 ° at the end of the transparent resin layer Conductive film. 2. The low-resistance transparent according to claim 1 , wherein an average thickness of the transparent resin layer is thinner than a maximum thickness of the fine metal wires, and a thickness of a central portion of the transparent resin layer is thinner than a thickness of an outer peripheral portion. Conductive film. The low resistance transparent conductive film according to claim 1, wherein at least a part of the highest part of the thin metal wire layer is in direct contact with the transparent conductive film. On a transparent base material having flexibility, a metal fine wire layer formed of a fine metal wire having a mesh shape and a shape in which the thickness in the cross-sectional direction decreases toward the outside directly or through an underlayer,
Next, a transparent resin layer-forming coating material containing a solvent and a resin component is formed on the transparent substrate having the fine metal wire layer at a film thickness of 0.5 to 5 times the maximum thickness of the fine metal wire. Apply and then dry to form a transparent resin layer covering the mesh of the metal fine wire layer and its peripheral edge,
Next, a method for producing a low-resistance transparent conductive film, comprising forming a transparent conductive film so as to cover the fine metal wire layer and the transparent resin layer. A solar cell comprising the low-resistance transparent conductive film according to any one of claims 1 to 3 . An electronic apparatus comprising the low-resistance transparent conductive film according to any one of claims 1 to 3 .

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