JP5548428B2 - Method for producing transparent conductive film and transparent conductive film - Google Patents

Description

The present invention relates to a method for producing a transparent conductive film and a conductive film. More specifically, the present invention relates to a method for producing a transparent conductive film and a transparent conductive film, which are excellent in transparency, have a low surface resistivity, have surface smoothness and can be produced at low cost. .
The transparent conductive film of the present invention can be used, for example, as an electrode member of an electronic device such as a thin film solar cell, EL illumination, touch panel, and light control film, and an electromagnetic shielding material for electromagnetic shielding.

  A transparent conductive film in which a thin line mesh pattern serving as an electrode is formed on one surface of a transparent base material is used for electrodes for light-emitting elements such as solar cell collectors and electroluminescence illumination (hereinafter referred to as EL illumination), transparent surfaces It is widely used as an electrode of an input device such as an electrode such as a heating element, a light control film, an electromagnetic shielding film of an electromagnetic shielding material, or a transparent touch panel.

Conventionally, electrode materials for transparent conductors that can be generally used include tin oxide (SnO ₂ ) -based, indium oxide (In ₂ O ₃ ) -based, and indium-tin formed by sputtering or vacuum deposition. Metal oxide type such as oxide (ITO) type and zinc oxide (ZnO) type and metal transparent conductive films are known.

However, with the recent increase in size of displays, the above-mentioned metal oxide transparent conductive film cannot be said to have a sufficiently low resistance, resulting in uneven brightness, resulting in an increase in the size and cost of EL lighting. It is an obstacle.
For this reason, in order to lower the resistance of the transparent conductive film, it is known to provide a protective film made of resin mixed with ITO fine powder on the transparent conductive film (Patent Document 1).
Similarly, it is disclosed that a conductive polymer is laminated on a metal-based transparent conductive thin film in order to achieve transparency and low resistance (Patent Document 2).

  On the other hand, in the electromagnetic wave shielding film used for the purpose of shielding unnecessary electromagnetic waves from the plasma display, in addition to the above metal oxide based transparent conductive film, etching copper foil, printing silver paste, A method for producing a transparent conductive film having a lower resistance by forming a mesh pattern made of a metal thin film by a method such as electroplating an appropriate metal on a pattern formed by the photographic silver salt method (Patent Documents 3 to 5). Has been devised. However, in the case of a transparent conductive film using these metal mesh patterns, the conductivity is high only in the vicinity of the metal mesh fine wire, and the conductivity at the central portion of the opening in the metal mesh pattern is increased. Is not taken into account.

For this reason, when a transparent conductive film using these metal mesh patterns is used as an electrode member of a light emitting element such as an EL display or EL illumination, light is emitted only in the vicinity of the metal mesh pattern, and the luminance as a whole There is a problem that will decrease.
Moreover, the thickness of the metal film of these metal mesh patterns is generally about 1 μm to 15 μm. For example, elements such as EL lighting, organic thin film solar cells, and light control films are formed extremely thin by vapor deposition or sputtering. Therefore, when these metal films are used as electrodes, the thickness of the metal film of the electrodes becomes a steep step, which makes it difficult to form an element.

  On the other hand, various ingenuity has been made with respect to enhancing the conductivity and ensuring the transparency to compensate for the low conductivity, which is a drawback of the transparent conductive film and the conductive polymer.

For example, Patent Document 6 discloses a transparent conductive film in which a conductive metal mesh layer using a base metal or an alloy made of a base metal and a conductive polymer layer are laminated on a transparent substrate.
Here, the base metal or an alloy made of a base metal is at least one selected from aluminum, nickel, zinc, iron, tin, titanium, molybdenum, stainless steel, and permalloy, and the transparent conductive film has excellent conductivity, It is said that the uniformity of the conductive performance is high.

  In Patent Document 7, a metal film including a mesh shape is laminated on a transparent substrate, a transparent resin film is provided in the opening, and a transparent conductive film is formed on the metal film and / or the transparent resin film. A transparent electrode substrate is disclosed. The metal film has a thickness of 15 μm or less, a line width of 60 μm or less, a total light transmittance of 70% or more, and a surface resistivity of 1Ω / □ or less.

  Patent Document 8 discloses an electrode composed of a mesh electrode and a conductive polymer layer formed at least in the opening of the mesh electrode as an electrode for an organic thin film solar cell. Compared to the conventional transparent conductive film such as ITO, the manufacturing cost can be reduced.

  Patent Document 9 discloses an electrode formed of a network metal layer made of metal nanoparticles and a transparent conductive polymer on a transparent substrate as an electrode of a light emitting device using an organic EL element. Yes. As the metal arranged in a network, a metal formed by printing a solution in which metal nanoparticles are dispersed is used, and the resistance is low.

Japanese Patent Laid-Open No. 7-219697 JP-A-2005-19056 JP 11-298186 A JP 2001-196784 A WO2004 / 007810 JP 2009-81104 A JP 2005-332705 A JP 2009-76668 A JP 2008-130449 A

  As described above, in the transparent conductive film using the transparent conductive film by the metal oxide vapor deposition film of the prior art, it is necessary to reduce the film thickness in order to increase the total light transmittance. On the contrary, if the film thickness is increased in order to decrease the surface resistivity, the total light transmittance is decreased. Therefore, in order to improve the conductivity of the transparent conductive film, a method of laminating a protective film made of resin mixed with ITO fine powder (see Patent Document 1) and a method of laminating a transparent conductive polymer have been studied. (Refer to Patent Document 2), however, there is a problem that remarkable improvement cannot be achieved.

  Moreover, in patent document 6, although the transparent conductive film which laminated | stacked the conductive metal mesh layer and the conductive polymer layer on the transparent base material is disclosed, according to the Example, it is adhesive to PET film. A metal foil having a thickness of 5 μm, a thickness of 9 μm, and an aperture ratio of 93% is formed by laminating a metal foil having a thickness of 5 μm (a copper foil in the comparative example and a base metal foil such as aluminum in the example). A transparent conductive film formed and coated with a conductive polymer on a metal mesh layer so that the thickness after drying is 250 nm is shown. The total light transmittance is as high as 82 to 84%, but the surface resistivity is 300 to 400Ω / □ in all cases, and the value is not so low. In addition, since the metal mesh layer is formed by etching processing, most of the metal foil is dissolved and discarded, so that resources are wasted and wastewater treatment costs increase. Is present.

  Moreover, in patent document 7, after forming a metal mesh pattern by the etching method of metal foil or the method of laminating a metal plating layer on developed silver generated by photographic silver, and filling the opening with a transparent resin layer It is disclosed that a transparent conductive film is formed on a metal mesh pattern and a transparent resin layer in an opening. According to the embodiment, the total light transmittance can be obtained by etching a copper foil having a thickness of 12 μm or by forming a lattice mesh with a laminated plating film having a total film thickness of 6 μm and embedding the resin so that the resin remains only at the opening of the mesh. Is 75%, and the surface resistivity is 0.1Ω / □ or less, and excellent conductivity is obtained. However, when the mesh thickness is to be less than 1 μm, for example, it is difficult to smoothly laminate the transparent resin layer so that the upper surface of the metal mesh pattern is not buried in the transparent resin layer that fills the opening. There is a problem that the manufacturing cost increases.

Patent Document 8 discloses an electrode composed of a mesh electrode and a conductive polymer layer formed at least in the opening of the mesh electrode as an electrode for an organic thin film solar cell. Compared to the conventional transparent conductive film such as ITO, the manufacturing cost can be reduced.
According to Example 1, a mesh electrode having a line width of 500 μm, a line spacing of 2,500 μm, and a thickness of 0.1 μm was formed on a PEN film substrate by vacuum deposition using a patterning mask, and then conductive by spin coating. A functional polymer is applied to a thickness of 100 nm. According to Example 2, an Ag thin film formed by vacuum deposition is patterned by etching to form a mesh electrode having a line width of 10 μm, a line interval of 100 μm, and a thickness of 0.1 μm, and then a conductive polymer is formed by spin coating. It is applied to a thickness of 100 nm. In any of the examples, a photomask is used to form a fine line pattern, and the conductive polymer layer having the same thickness as that of the mesh electrode is formed by a spin coating method. Is not economical. In addition, when vacuum deposition is performed using a patterning mask, the thickness of the patterning mask is usually 5 μm to 20 μm, and since the cross-sectional shape of the mask is rectangular, a metal thin film is uniformly formed on the patterning mask. However, in forming a fine line pattern, it is difficult to coat the patterning mask openings uniformly with a metal film with a normal vacuum vapor deposition machine or sputtering apparatus. There is a problem that the line width needs to be increased and the transparency is impaired, and the line spacing must be widened to ensure transparency, resulting in poor efficiency. In the case of etching, the film surface may be eroded by an etchant and become opaque. In this case, there is a problem that a separate transparent treatment is required to obtain a predetermined transparency. Moreover, there is no description about the smoothness of the surface of the conductive polymer layer.

Patent Document 9 discloses an electrode formed of a network metal layer made of metal nanoparticles and a transparent conductive polymer on a transparent substrate as an electrode of a light emitting device using an organic EL element. Yes. The film thickness of the transparent electrode layer in which the transparent conductive polymer is laminated on the network-like metal layer is preferably 100 nm to 10 μm, and more preferably 200 nm to 5 μm, but the particle diameter of the metal powder used Therefore, the thickness of the network metal layer needs to be at least several times to about 10 times the particle diameter of the metal powder.
According to Example 1, the conductive polymer is screen-printed and dried on the mesh-like metal layer, thereby forming a transparent conductive polymer layer and filling the recesses of the mesh-like metal. . However, when forming a mesh pattern of a metal paste using a mesh-like screen plate as described in paragraphs 0039 and 0097 of the same document, the coating thickness (dried) of the metal paste supplied into the holes of the screen plate Since the former is almost the same as the thickness of the screen plate, it is not easy to form a thin metal mesh. It is possible to increase the supply amount (volume) to the screen plate by reducing the concentration of the metal paste, but the shape of the printed metal layer changes when the solvent is dried and the mesh pattern of the screen plate cannot be reproduced. There is.
In addition, according to Example 2, since it is an irregular network-like metal layer that grows in a self-forming manner, the maximum distance between the openings cannot be controlled, and the surface resistance cannot be controlled. There is a problem that the numerical value of the rate cannot be controlled within a certain range. Also, silver nanoparticles are very expensive and not economical. As for smoothness, paragraph 0049 of the same document describes that the surface of the transparent conductive polymer layer is smooth because the metal-free portion is filled with the transparent conductive polymer. In addition, it is stated that production in a vacuum such as vacuum deposition or sputtering is unnecessary by using a printing technique for forming the metal layer, and no consideration is given to formation by a dry process.

  Thus, in the prior art, a method for producing a transparent conductive film, which is excellent in transparency and has a low surface resistivity, has surface smoothness and can be produced at low cost, and is transparent. The conductive film has not been put to practical use.

  The present invention has been made in view of the above problems to be solved, and has excellent transparency and low surface resistivity, and also has surface smoothness and can be manufactured at low cost. It aims at providing the manufacturing method of a transparent conductive film, and a transparent conductive film.

In order to solve such a problem, the present invention is a method for producing a transparent conductive film in which a fine metal mesh pattern of a metal thin film is formed on one side of a transparent resin substrate, and the following (1) to (4) The process of
(1) forming a pattern obtained by printing a solvent-soluble printing material on one surface of a transparent resin base material as a negative shielding mask for the fine line mesh pattern;
(2) A step of forming a metal thin film having a thickness of 0.08 μm to 0.5 μm on the transparent resin base material by sputtering or vacuum deposition in a state where the shielding mask covers the transparent resin base material. ,
(3) Dissolving and removing the shielding mask in a solvent, and exposing a fine line mesh pattern made of the metal thin film;
(4) A conductive polymer as a conductive resin layer having transparency on a convex portion formed by the metal thin film of the fine line mesh pattern and a part or the entire surface of the concave opening where the metal thin film is not formed , A conductive resin having transparency selected from the group consisting of a carbon tube and / or a conductive polymer in which carbon particles are dispersed, a carbon tube and / or a resin in which carbon particles are dispersed, and the convex portion A step of forming a conductive resin layer so that the surface height difference of the coating surface by the conductive resin layer is 50 to 400 nm, so as to be buried;
The manufacturing method of the transparent conductive film characterized by including this is provided.

In the step of forming the conductive resin layer, the conductive resin layer is preferably formed by applying a conductive resin having transparency.
In the step of forming the conductive resin layer, the conductive resin layer is transferred by pressing a transparent conductive film obtained by applying a transparent conductive resin on a separately prepared substrate so as to have a uniform surface. Is preferably formed.

Further, the maximum height of the shielding mask from the transparent resin base material surface is 5 μm or less, and the cross-sectional shape is a bowl shape or an arc shape that decreases toward the opening, and is relative to the maximum height of the shielding mask . wherein the ratio of the line width of the fine line mesh pattern is equal to or greater than 2, the ratio of line spacing of said dividing mesh pattern to the maximum height of the shielding mask is preferably 30 or more.
The fine line mesh pattern preferably has a line width of 5 μm to 30 μm and a thickness of 0.08 μm to 0.5 μm.
Moreover, it is preferable that the said metal thin film consists of 1 or more types of metals selected from the metal group which consists of copper, aluminum, silver, zinc, tin, chromium, nickel.

In the present invention, a fine line mesh pattern made of a metal thin film is formed on one surface of a transparent resin base material, and the fine line mesh pattern has a line interval of 100 μm to 10 mm, a line width of 5 μm to 30 μm, and a thickness. 0.08 μm to 0.5 μm, the aperture ratio formed by the fine line mesh pattern is 70% or more and less than 100%, and the convex part formed by the metal thin film of the fine line mesh pattern and the metal thin film are not formed. Part of or the entire surface of the concave opening is dispersed as a conductive resin layer having transparency , conductive polymer, carbon tube and / or carbon particles dispersed in conductive polymer, carbon tube and / or carbon particles. The conductive resin layer is coated with a conductive resin having transparency selected from the group consisting of the resin, and the surface height difference of the conductive resin layer is A transparent conductive film having a thickness of 50 to 400 nm is provided.

The metal thin film is formed by sputtering or vacuum using a pattern formed by printing a solvent-soluble printing material formed on one side of the transparent resin substrate as a negative shielding mask for the fine line mesh pattern. It is preferably formed by vapor deposition.
Moreover, it is preferable that the said metal thin film consists of 1 or more types of metals selected from the metal group which consists of copper, aluminum, silver, zinc, tin, chromium, nickel.
Moreover, it is preferable that the surface of the said metal thin film is blackened.

ADVANTAGE OF THE INVENTION According to this invention, while being excellent in transparency and having a low surface resistivity, the conductive film which has surface smoothness can be provided.
When forming a fine line mesh pattern by lift-off method using a shielding mask, the cross-sectional shape of the edge portion of the shielding mask is gradually lowered toward the substrate surface by using a printing method to form the shielding mask. The surface of the base material exposed in step and the surface on the shielding mask are smoothly continuous, so that the metal thin film has improved adhesion to the transparent base material in the opening, and the fine line mesh pattern is based on the pattern of the opening of the shielding mask. Can be formed with good reproducibility. Thereby, a thin metal mesh pattern with a thin wire mesh pattern can be easily formed by sputtering or vacuum deposition. And by covering the metal thin film of a thin fine wire mesh pattern with a transparent conductive resin, the conductive film has excellent transparency and low surface resistivity, and also has surface smoothness. Can be manufactured at low cost.

It is a top view which shows an example of schematic structure of the transparent conductive film concerning this invention. It is an expanded sectional view by the AA arrow of FIG. (A)-(e) is sectional drawing which shows the process of (1)-(4) in order in the manufacturing method of this invention. 2 is a diagram illustrating a surface shape of Example 1. FIG. FIG. 6 is a diagram showing the surface shape of Example 2. FIG. 6 is a diagram showing the surface shape of Example 3. 6 is a diagram showing a surface shape of Comparative Example 1. FIG. It is a conceptual diagram which shows the light emission condition of the dispersion | distribution type inorganic EL light emitting element produced in Example 3, (a) is a top view, (b) is sectional drawing. It is a conceptual diagram which shows the light emission condition of the dispersion | distribution type inorganic EL light emitting element produced by the comparative example 1, (a) is a top view, (b) is sectional drawing.

The present invention will be described below with reference to the drawings based on the best mode.
FIG. 1 is a plan view showing an example of a schematic configuration of a transparent conductive film according to the present invention, and FIG. 2 is an enlarged sectional view taken along the line AA in FIG.

The transparent conductive film 1 of the present invention shown in FIG. 1 has a lattice-like pattern composed of a fine mesh pattern of a metal thin film 5 on the entire surface of one side of a long transparent substrate 4. A conductive resin layer having transparency is coated or applied to the entire surface of the convex portion formed by the metal thin film 5 and the concave opening where the metal thin film 5 is not formed.
The transparent substrate 4 includes at least the transparent resin substrate 2 made of a film-like resin. If necessary, an adhesive layer and a release film (both not shown) for protecting the pressure-sensitive adhesive layer can be provided on the other surface (back surface) of the transparent resin substrate 2. The transparent conductive film of the present invention provided with the pressure-sensitive adhesive layer can be easily attached to the surface of glass or the like by peeling off the release film. Moreover, you may provide a reflective layer and a light shielding layer in the other surface of the transparent resin base material 2 as needed.

FIG. 2 is an enlarged cross-sectional view taken along line AA in FIG. 1, and a primer layer 3 is laminated on one side of a long transparent resin substrate 2, and a metal thin film 5 is formed on the primer layer 3. A grid-like pattern composed of the fine line mesh pattern is disposed on a part or the entire surface of the fine line mesh pattern, and the convex part formed of the metal thin film 5 of the fine line mesh pattern and the concave opening part 7 where the metal thin film 5 is not formed. The conductive resin layer 6 having transparency is coated or applied by pressure bonding and transfer. Moreover, the conductive layer is formed so that the surface height difference d of the surface covered with the conductive resin layer 6 is 50 to 400 nm.
In the preferred embodiment, the fine line mesh pattern made of the metal thin film 5 has a line interval s of 100 μm to 10 mm, a line width w of 5 to 30 μm, and is formed in a lattice pattern arranged at a constant interval and opened. Since it has the part 7 and there is a gap such that the aperture ratio is 70% or more and less than 100%, it has transparency (not visually observed).

  The fine line pitch interval (that is, the line interval s) of the fine line mesh pattern can be arbitrarily set, but the fine line pitch interval is preferably about 8 μm to 10 mm, more preferably about 100 μm to 10 mm. If the fine wire pitch interval is too wide, the distance from the fine wire to the center of the opening 7 becomes long. Therefore, in order to sufficiently reduce the surface resistivity of the transparent conductive film, it is necessary to apply a thick conductive layer. In addition, since a large amount of expensive conductive polymer is required, it is not economical and the transparency of the opening 7 is lost. Further, when the line width is made the same and the fine wire pitch interval is made too narrow, the aperture ratio is lowered, and there is a problem that the total light transmittance is lowered.

(Transparent substrate)
The transparent resin substrate 2 used in the present invention preferably has transparency in the visible region and generally has a total light transmittance of 90% or more. Especially, the resin film which has flexibility is preferable as the transparent resin base material 2 since it is excellent in handleability. Specific examples of the resin film used for the transparent resin substrate 2 include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylic resins, epoxy resins, fluororesins, silicone resins, polycarbonate resins, A single-layer film having a thickness of 50 to 300 μm made of acetate resin, triacetate resin, polyarylate resin, polyvinyl chloride, polysulfone resin, polyether sulfone resin, polyimide resin, polyamide resin, polyolefin resin, cyclic polyolefin resin, or the like A multi-layer composite film consisting of
In addition, the transparent resin base material in this invention should just be a base material which mainly has transparent resin so that it may illustrate, and components other than resin (for example, other additives, a surface layer, a back surface layer, As an intermediate layer).

(Generation of lattice metal thin film layer by metal deposition)
The metal thin film with a fine line mesh pattern used in the present invention is obtained by dissolving a shielding mask in a solvent after sputtering or vacuum deposition of metal using a pattern printed with a solvent-soluble printing material as a shielding mask. A metal thin film formed by a peeling (lift-off) method performed by removing is used.

A method for forming a fine line mesh pattern by a peeling (lift-off) method performed using a pattern printed with a solvent-soluble printing material as a shielding mask is as follows.
In FIG. 3, the metal thin film before lift-off is denoted by reference numeral 9, and the metal thin film after lift-off is denoted by reference numeral 5. In the following description, before and after the lift-off may be distinguished depending on these signs.

  First, on the transparent substrate 4 shown in FIG. 3 (a), as shown in FIG. 3 (b), a portion that becomes the shielding mask 8 is printed with a printing material mainly composed of a solvent-soluble resin. The shielding mask 8 forms an opening 8a so that the surface of the transparent substrate 4 is exposed. The opening 8a is a pattern corresponding to the fine line mesh pattern, and the shielding mask 8 is a pattern opposite to the fine line mesh pattern. The maximum width of the shielding mask 8 corresponds to the line interval s of the fine line mesh pattern, and the width of the opening 8a (opening width) corresponds to the line width w of the fine line mesh pattern.

  Next, as shown in FIG. 3C, a metal thin film 9 is formed on the transparent substrate 4 and the shielding mask 8 made of a printing material by sputtering or vacuum deposition over part or the entire surface. The metal thin film 9 is continuously formed from the top of the transparent substrate 4 exposed at the opening 8 a of the shielding mask 8 to the surrounding shielding mask 8. Although the figure shows a case where the metal thin film 9 is formed over the entire surface, the metal thin film may be formed at least in the opening 8a where the surface of the transparent substrate 4 is exposed and in the vicinity thereof. A portion of the metal thin film 9 formed on the shielding mask 8 is removed together with the peeling of the shielding mask 8 in a later process.

Next, as shown in FIG. 3 (d), the shielding mask 8 and the metal thin film on the mask 8 are simultaneously removed using a solvent, and the metal thin film left on the transparent substrate 4 is formed. A metal thin film 5 having a fine line mesh pattern is obtained.
The solvent used in this step is not particularly limited as long as it can dissolve the solvent-soluble printing material. As long as the printing material can be dissolved in two or more kinds of solvents, any one kind of solvents or two or more kinds of mixed solvents may be used. When the shielding mask 8 is dissolved and removed in the solvent, it may be peeled off from the transparent substrate 4 before it is completely dissolved.

The printing method of the portion to be the shielding mask 8 can be selected as appropriate from screen printing, gravure printing, offset printing, etc., but screen printing and gravure printing suitable for precision printing that can obtain the desired fine line mesh pattern are preferable. In particular, gravure printing that can print a seamless pattern at a high speed is more preferable.
Further, the shielding mask 8 has a maximum height h of 5 μm or less and a cross-sectional shape directed toward the opening 8a so that a uniform metal thin film 9 can be easily obtained in the opening 8a even with a general vacuum vapor deposition machine. The ratio of the line width w of the fine line mesh pattern to the maximum height h of the shielding mask 8 is 2 or more (that is, the value of w / h is 2 or more). maximum ratio of line spacing s of fine wire mesh pattern to the height h is 30 or more (that is, the value of s / h is 30 or higher) is preferably. In other words, the shielding mask 8, the ratio of the opening width w of the shielding mask 8 with respect to the maximum height h of the shielding mask 8 is equal to or greater than 2, the ratio of the maximum width s of the shielding mask 8 with respect to the maximum height h of the shielding mask 8 It is preferable that it is 30 or more.
If the maximum height h of the shielding mask 8 is larger than 5 μm, it is unnecessary for the purpose of shielding, so the resin is wasted and not economical, and the ratio of the line width w to the maximum height h is less than 2 . If the ratio of the line interval s to the maximum height h is less than 30 , the angle formed between the end of the shielding mask 8 and the opening 8a becomes too steep, and the top of the shielding mask 8 is opened to the opening 8a. Uniform formation of the metal thin film 9 becomes difficult.
Here, the maximum height h of the shielding mask 8 is a height (thickness) at a position where the height (thickness) of the shielding mask 8 is the largest from the surface of the transparent substrate 4 as shown in FIG. In the case where the transparent substrate 4 is a single layer of the transparent resin substrate 2, the primer layer 3 or the like is formed from the surface of the transparent resin substrate 2 or the primer layer 3 or the like on the surface of the transparent resin substrate 2. Measured from the surface.

It is preferable that the transparent substrate 4 on which the shielding mask 8 is printed is appropriately subjected to surface treatment so that the shielding mask 8 is printed accurately.
The surface treatment method is not limited as long as the adhesion to the transparent resin substrate 2 is high and the adhesion to the metal to be sputtered or vacuum-deposited is high, but the primer layer 3 is coated with a resin that satisfies the above conditions. It is preferable in view of productivity and economy.

  The metal constituting the metal thin film 9 can be sputtered or vacuum-deposited and is not limited as long as it has high conductivity, but is generally selected from a metal group consisting of copper, aluminum, silver, zinc, tin, chromium and nickel. It is preferable to consist of one or more kinds of metals. When the metal thin film 9 is made of two or more kinds of metals, an alloy made of a uniform material may be used, or a structure in which different materials are laminated may be used. Of these, copper and aluminum, which have high conductivity and are relatively inexpensive, are more preferable.

In order to ensure transparency (not visually observed), a fine line mesh pattern is constituted by fine lines made of the metal thin film 5. The line width w of the thin metal mesh pattern 5 is preferably 5 to 30 μm, and more preferably 5 to 20 μm. The thickness t of the metal thin film 5 having a fine line mesh pattern can be arbitrarily changed depending on desired characteristics, but is preferably in the range of 0.08 μm to 0.5 μm, more preferably 0.1 to 0.3 μm. It is a range.
As described above, when the line width w of the fine line mesh pattern of the present invention is reduced to less than 5 μm, the total light transmittance (not visible) increases, but the surface resistivity of the transparent conductive film decreases, On the contrary, when the line width w is increased to exceed 30 μm, the total light transmittance is reduced, but the surface resistivity is increased. Further, if the line width w is a fine line of less than 5 μm, it is not preferable because the manufacturing cost of a printing plate for masking a portion other than a portion that becomes a fine line mesh pattern made of a metal thin film is markedly increased.
On the other hand, when the thickness t of the metal thin film exceeds 0.5 μm, the surface resistivity of the conductive film is lowered , but the convex height of the metal thin film having a fine line mesh pattern is increased, which is not preferable. Even in this case, it is possible to smooth the surface by increasing the coating thickness of the conductive resin layer 6 to be described later. However, the transparency is impaired and a relatively expensive conductive polymer is required. This is not preferable because the manufacturing cost increases. When the thickness t of the thin metal film less than 0.08 .mu.m, since convex height of the metal thin film is smaller conductive film 1 surface resistivity is increased undesirably.

  The metal thin film formed by sputtering or vacuum deposition of an arbitrary fine line mesh pattern formed on the transparent base material according to the present invention has a very thin film thickness but is highly conductive. The transparency of the film can be increased.

(Conductive resin layer)
The conductive resin layer 6 used in the present invention is applied to impart conductivity to the concave openings 7 of the fine line mesh pattern and to relieve irregularities on the film surface caused by the end portions of the metal thin film 5. .
The conductive resin layer 6 can be formed by applying a conductive resin composed of a conductive polymer, a carbon tube, a resin in which carbon particles are dispersed, or the like. The coating method is not particularly limited as long as a predetermined film thickness can be obtained uniformly, but the die coating method, spin coating method, dip coating method, roll coating method, bar coating method, gravure coating method, screen printing method, offset printing method. , Inkjet printing method can be selected as appropriate, and among them, it can be selected from die coating method, roll coating method, bar coating method, gravure coating method, offset printing method which can be processed continuously and at high speed by roll-to-roll. preferable.

  The conductive polymer in the case where the conductive resin layer 6 is composed of a conductive polymer is not particularly limited as long as it is a transparent and conductive polymer, and is polythiophene (or a derivative thereof), polyaniline (or a component thereof). Derivatives), polypyrrole (or derivatives thereof) and the like. From the viewpoint of conductivity, this conductive resin composition includes inorganic semiconductors such as CuI, CuS, and FeO, polystyrene sulfonic acid (salt), p-toluenesulfonic acid (salt), camphor sulfonic acid (salt), polystyrene- A dopant such as a maleic acid (salt) copolymer may be contained. An example is PSS / PEDOT (poly-3,4-ethylenedioxythiophene doped with polystyrene sulfonic acid).

  As the resin in the case where the conductive resin layer 6 is made of a resin in which carbon tubes and / or carbon particles are dispersed, an appropriate non-conductive resin can be used in addition to the above-described conductive polymer. The amount of carbon tube and / or carbon particles added is set so as not to impair the transparency of the conductive resin layer 6.

  The conductive resin layer 6 is preferably formed on at least the transparent substrate 4 of the opening 7, and is formed from the transparent substrate 4 to a thickness not less than the same thickness as the metal thin film 5 and not more than 5 times. Moreover, it is more preferable if it forms continuously on the metal thin film 5 from the opening part 7. FIG. Even in this case, the thickness of the conductive resin layer 6 on the opening 7 is preferably equal to or more than 5 times the thickness of the metal thin film 5 from the transparent base 4 of the opening 7. If it is thinner than this, the effect of relief of unevenness becomes too small, and if it is thicker than this, the metal thin film 5 is completely embedded in the conductive resin layer 6 and the influence of the unevenness of the metal thin film 5 is almost eliminated, but the transparency is impaired. In addition, since a larger amount of conductive resin is required, it is not economical, and since the distance from the surface of the metal thin film 5 to the surface of the conductive resin layer 6 increases, the electrical resistance increases and is not practical.

Example 1
First, the primer layer 3 was applied by a bar method to a 100 μm PET film (transparent resin substrate 2) that had been previously subjected to corona treatment, easy adhesion treatment, and the like to obtain a transparent substrate.
Next, a water-soluble shielding mask resin was applied on the primer layer by gravure printing and dried to form a negative shielding mask for a fine line mesh pattern. At this time, the line of the aluminum layer of the metal thin film formed as the gravure plate is inclined 45 degrees with respect to the axis of the gravure plate, the line spacing of the aluminum layer is 200 μm, and the line width is 25 μm. I used the following.

Next, using a vacuum deposition apparatus, aluminum was deposited on the shielding mask and the exposed primer layer to a thickness of 0.2 μm.
Next, the shielding mask was dissolved with water, and the shielding mask and the aluminum layer on the shielding mask were peeled off. As a result, as described above, a thin wire mesh pattern of an aluminum layer having a line spacing of 200 μm and a line width of 25 μm was formed on the transparent substrate.
Then, S-300 of Nippon Agfa Materials Co., Ltd. was applied by a bar method so that the thickness after drying was 0.25 μm, and the conductive film 1 was obtained.

  About the obtained electroconductive film, the total light transmittance, direct-current resistance, and surface resistivity were calculated | required with the following method. Moreover, the shape of the surface of the conductive film was measured with a surface roughness meter (manufactured by Tokyo Seimitsu), and it was evaluated whether the unevenness at the end of the metal thin film was relaxed.

Total light transmittance: The conductive film 1 was cut into 4 cm square and measured with a haze meter NDH 2000 manufactured by Nippon Denshoku Industries Co., Ltd.
DC resistance: The conductive film 1 was cut into a length of 10 cm and a length of 12 cm, a metal terminal having a width of 10 cm was placed on the conductive resin layer of the conductive film 1 at a distance of 10 cm, and the resistance between the terminals was measured.
Surface resistivity: Measured with a non-contact type surface resistance measuring instrument manufactured by Napson Corporation
Surface shape: A sample was cut into 2 cm square, and the surface height difference was measured in a direction perpendicular to the fine line mesh pattern with a surface roughness meter (Surfcom 1900DX) manufactured by Tokyo Seimitsu. The measurement distance was 1.25 mm, the cutoff wavelength was 0.25 mm, and the cutoff ratio was 100. The surface height difference is indicated by “maximum height” of JIS B0601 (the sum of the maximum value of the peak height and the maximum value of the valley depth. The symbol is Rz in the 2001 standard and Ry in the 1994 standard).

(Example 2)
The same process as in Example 1 was performed until a fine line mesh pattern of an aluminum layer having a line interval of 200 μm and a line width of 25 μm was formed on a transparent substrate.
Next, 0.1 part by weight of a 10% aqueous solution of polyvinyl alcohol was added to 1 part by weight of S-300 manufactured by Nippon Agfa Materials Co., Ltd. and stirred well to obtain a conductive polymer solution. This was applied so that the thickness after drying was 0.5 μm to obtain a transparent conductive film 1.

(Example 3)
The same process as in Example 1 was performed until a fine line mesh pattern of an aluminum layer having a line interval of 200 μm and a line width of 25 μm was formed on a transparent substrate.
Next, 0.1 part by weight of a 10% aqueous solution of polyvinyl alcohol was added to 1 part by weight of S-300 manufactured by Nippon Agfa Materials Co., Ltd. and stirred well to obtain a conductive polymer solution. This was applied to a non-silicone release film by a bar method so that the thickness after drying was 0.5 μm. The transparent conductive film formed on the release film and the fine-line mesh pattern of the aluminum layer on the transparent substrate obtained in the above process are overlapped and thermocompression bonded with a laminator. Film 1 was obtained. At this time, the temperature of the nip roll of the laminator was 120 ° C., and the line speed was 0.5 m / min. Moreover, the dispersion type inorganic EL light emitting element was created with the obtained electroconductive film, and the light emission state was observed. The emission luminance was measured with a spectral radiance meter CS-1000A manufactured by Konica Minolta Sensing Co., Ltd.

(Comparative Example 1)
The same process as in Example 1 was performed until a fine line mesh pattern of an aluminum layer having a line interval of 200 μm and a line width of 25 μm was formed on a transparent substrate, but a conductive polymer was not applied. . In the same manner as in Example 3, a dispersion-type inorganic EL element was prepared from the obtained conductive film, and the light emission state of the opening of the fine line mesh pattern was observed. Further, the emission luminance was measured in the same manner as in Example 3.

  The results obtained for the conductive films of Examples 1 to 3 and Comparative Example 1 are shown in Table 1, and the results of measuring the light emission state and the light emission luminance of Example 3 and Comparative Example 1 are shown in Table 2.

Moreover, about Examples 1-3 and the comparative example 1, the mode of the cross section obtained with the surface roughness meter is shown to the graph of FIGS.
8 and 9 conceptually show the light emission states of the dispersion-type inorganic EL light-emitting elements prepared for Example 3 and Comparative Example 1. FIG. 8 and 9, reference numeral 1 is the conductive film of the present invention shown in FIG. 3 (e), reference numeral 10 is a conductive film not coated with the conductive polymer shown in FIG. 3 (d), and reference numeral 11 is EL element layer, reference numeral 12 is a counter electrode layer, reference numeral 13 is a light emitting part, reference numeral 14 is a shadow part of the metal thin film 5 having a fine line mesh pattern, and reference numeral 15 is a part not emitting light. FIG. 8 and FIG. 9 are shown for conceptual explanation of the present invention, and are schematic diagrams showing the difference in the light emission state of the dispersed inorganic EL element depending on the presence or absence of the conductive resin layer according to the present invention. It is. There are two types of general inorganic EL elements, a dispersion type and a thin film type. The main difference between the two is that the structure of the dispersion type inorganic EL element is between the counter electrode layer 12 (back electrode) and the transparent electrode. 1 has a phosphor layer having a thickness of several tens of μm and an EL element layer 11 composed of one dielectric layer on the counter electrode layer side of the phosphor layer, whereas the structure of a thin-film inorganic EL element Has a phosphor layer having a thickness of about 0.5 μm between the counter electrode layer (back electrode) and the transparent electrode, and an EL element layer composed of one dielectric layer on both sides of the phosphor layer. Differ.
In addition, specific configurations in the case where the EL element layer is a general organic EL element layer include various layers (not shown) such as a light emitting layer, a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer. 3).

As can be seen from FIGS. 4 to 7, the high step at the end of the metal thin film recognized in Comparative Example 1 is relaxed in the example, and in particular, the base is widened and the steep step is eliminated in Example 3. Was within the range of 50 nm to 400 nm, and the relaxation of the step was confirmed.
Further, as shown in FIG. 9, the conductor of the transparent conductive film 10 emits light only in the vicinity of the metal thin film 5 with the fine line mesh pattern when only the metal thin film 5 with the fine line mesh pattern is used, but as shown in FIG. Further, by covering the openings of the fine line mesh pattern with the conductive polymer, the entire opening including the central part was improved so as to emit light, and the emission luminance was 2.8 times as shown in Table 2.
As described above, the transparent conductive film of the present invention has excellent transparency and conductivity, and also has conductivity in the central portion of the opening that has not been considered in the past, and has high smoothness. .

d: Surface height difference of the coating surface, h: Maximum height of shielding mask, s: Line spacing of fine mesh pattern (maximum width of shielding mask), t: Thickness of metal thin film, w: Line width of fine mesh pattern ( 1) conductive film having a conductive resin layer, 2 ... transparent resin substrate, 3 ... primer layer, 4 ... transparent substrate, 5 ... metal thin film after lift-off, 6 ... conductive resin layer, DESCRIPTION OF SYMBOLS 7 ... Opening of fine wire mesh pattern, 8 ... Shielding mask, 8a ... Opening of shielding mask, 9 ... Metal thin film before lift-off, 10 ... Conductive film without conductive resin layer, 11 ... EL element layer, 12 ... Counter electrode layer, 13 ... light emitting part, 14 ... shadow part of metal thin film of fine line mesh pattern, 15 ... part not emitting light.

Claims (10)

A method for producing a transparent conductive film in which a fine metal mesh pattern of a metal thin film is formed on one side of a transparent resin substrate, the following steps (1) to (4):
(1) forming a pattern obtained by printing a solvent-soluble printing material on one surface of a transparent resin base material as a negative shielding mask for the fine line mesh pattern;
(2) A step of forming a metal thin film having a thickness of 0.08 μm to 0.5 μm on the transparent resin base material by sputtering or vacuum deposition in a state where the shielding mask covers the transparent resin base material. ,
(3) Dissolving and removing the shielding mask in a solvent, and exposing a fine line mesh pattern made of the metal thin film;
(4) A conductive polymer as a conductive resin layer having transparency on a convex portion formed by the metal thin film of the fine line mesh pattern and a part or the entire surface of the concave opening where the metal thin film is not formed , A conductive resin having transparency selected from the group consisting of a carbon tube and / or a conductive polymer in which carbon particles are dispersed, a carbon tube and / or a resin in which carbon particles are dispersed, and the convex portion A step of forming a conductive resin layer so that the surface height difference of the coating surface by the conductive resin layer is 50 to 400 nm, so as to be buried;
The manufacturing method of the transparent conductive film characterized by including.   The method for producing a transparent conductive film according to claim 1, wherein in the step of forming the conductive resin layer, the conductive resin layer is formed by applying a conductive resin having transparency.   In the step of forming the conductive resin layer, the conductive resin layer is transferred by pressing a transparent conductive film obtained by applying a transparent conductive resin on a separately prepared substrate so as to have a uniform surface. The method for producing a transparent conductive film according to claim 1, wherein: The maximum height of the shielding mask from the surface of the transparent resin substrate is 5 μm or less, and the cross-sectional shape is a saddle shape or an arc shape that decreases toward the opening, and the fine line with respect to the maximum height of the shielding mask the ratio of the line width of the mesh pattern is equal to or greater than 2, according to claim 1, wherein the ratio of the line spacing of the fine-line mesh pattern to the maximum height of the shielding mask 30 or more Manufacturing method of transparent conductive film.   The method for producing a transparent conductive film according to claim 1, wherein the fine line mesh pattern has a line width of 5 μm to 30 μm and a thickness of 0.08 μm to 0.5 μm.   The said metal thin film consists of 1 or more types of metals selected from the metal group which consists of copper, aluminum, silver, zinc, tin, chromium, and nickel, In any one of Claims 1-5 characterized by the above-mentioned. A method for producing a transparent conductive film. A fine line mesh pattern made of a metal thin film is formed on one side of the transparent resin substrate. The fine line mesh pattern has a line interval of 100 μm to 10 mm, a line width of 5 μm to 30 μm, and a thickness of 0.08 μm to 0.00. 5 μm, the aperture ratio formed by the fine line mesh pattern is 70% or more and less than 100%, and one of the convex part formed by the metal thin film of the fine line mesh pattern and the concave opening part where the metal thin film is not formed. A part or the entire surface is made of a conductive polymer layer having transparency, a conductive polymer in which carbon tubes and / or carbon particles are dispersed, a resin in which carbon tubes and / or carbon particles are dispersed, The conductive resin layer is coated with a conductive resin having transparency, and the surface height difference of the conductive resin layer is 50 to 400 nm. A transparent conductive film, characterized in that   The metal thin film is formed by sputtering or vacuum evaporation using a pattern formed by printing a solvent-soluble printing material formed on one side of the transparent resin substrate as a negative shielding mask for the fine line mesh pattern. The transparent conductive film according to claim 7, which is formed.   The transparent conductive material according to claim 7 or 8, wherein the metal thin film is made of one or more metals selected from a metal group consisting of copper, aluminum, silver, zinc, tin, chromium, and nickel. the film.   The transparent conductive film according to claim 7, wherein the surface of the metal thin film is blackened.

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