WO2011021470A1 - Method for manufacturing a transparent conductive substrate, transparent conductive substrate, and electrochemical display element - Google Patents

Abstract

Disclosed are: a method for manufacturing a highly reliable transparent conductive substrate, a transparent conductive substrate and an electrochemical display element, which combine high transparency and low resistance. The method includes the following steps: a step for forming a groove in the surface of a transparent insulator; a step for forming a metallic electrode film on the surface of the transparent insulator comprising the groove; a step for removing, by means of grinding, the metallic electrode film formed outside the groove; and a step for forming a transparent conductive film on the surface of the transparent insulator comprising the metallic electrode film formed inside the groove.

Description

Transparent conductive substrate manufacturing method, transparent conductive substrate, and electrochemical display element

The present invention relates to a method for producing a transparent conductive substrate, a transparent conductive substrate, and an electrochemical display element.

In devices that require a transparent conductive substrate having a transparent conductive film, such as flat panel displays and solar cells, it is required to reduce the electrical resistance of the transparent conductive film in order to improve electrical characteristics. However, in transparent conductive films represented by recent ITO, it is difficult to reduce the electrical resistance while maintaining high transmittance because of the limit of resistivity inherent in the material, and display devices and solar cells that continue to increase in size It is becoming difficult to respond to

In order to cope with such a problem, an attempt has been made to realize high transmittance and low resistance by a substrate configuration in which a transparent conductive film and a thin metal electrode film functioning as an auxiliary electrode with low resistance are stacked ( Patent Document 1).

In Patent Document 1, since patterning is performed after forming a metal electrode film, there is a problem in that the manufacturing process is complicated and expensive.

On the other hand, a method has been proposed in which after forming a metal electrode film having an opening by plating, a transparent insulating material is applied and filled in the opening, and a transparent conductive film is formed thereon (see Patent Document 2). ).

However, in the method described in Patent Document 2, a transparent insulating material is applied and filled after forming a metal electrode film, and a transparent conductive film is formed thereon. Therefore, a transparent insulating material is provided between the metal electrode film and the transparent conductive film. There is a risk of interposition, which hinders the reduction in resistance.

Therefore, a pattern made of a transparent resin is formed on the transparent conductive film formed on the transparent substrate, and a metal electrode is formed by electroplating on the exposed portion of the transparent conductive film where the transparent resin on the transparent conductive film is not formed. A method for forming a film has been proposed (see Patent Document 3).

Japanese Patent Laid-Open No. 2-63019 JP 2005-332705 A JP 2007-149633 A

However, in the method described in Patent Document 3, unevenness in the thickness of the plated metal occurs depending on the resistance value of the transparent conductive film acting as an electrode for electroplating, and when used in a display element, this leads to unevenness in display density. In addition, when a further transparent conductive film is provided on the transparent resin and the metal electrode film, there is a problem that poor contact with the transparent conductive film occurs.

The present invention has been made in view of the above problems, and without complicating the manufacturing process and increasing the cost, has a high transmittance and low resistance, and a highly reliable method for manufacturing a transparent conductive substrate, An object is to provide a transparent conductive substrate and an electrochemical display element.

The above object is achieved by the invention described in any one of 1 to 10 below.

1. Forming a groove on the surface of the transparent insulator;
Forming a metal electrode film on the surface of the transparent insulator including the groove;
Removing the metal electrode film formed outside the groove by polishing;
Forming a transparent conductive film on the surface of the transparent insulator including the metal electrode film formed in the groove, and producing a transparent conductive substrate.

2. The height of the surface of the metal electrode film formed in the groove is the same as the height of the surface of the transparent insulator or lower than the height of the surface of the transparent insulator. The manufacturing method of the transparent conductive substrate of 1.

3. 3. The method for producing a transparent conductive substrate according to 1 or 2, wherein the groove is formed by using an etching method.

4. 3. The method for producing a transparent conductive substrate according to 1 or 2, wherein the groove is formed using a nanoimprint method.

5. 5. The method for manufacturing a transparent conductive substrate according to any one of 1 to 4, wherein the groove has a lattice shape or a stripe shape.

6. 1 to 5 above, further comprising a step of forming a protective film on the surface of the transparent conductive film opposite to the side in contact with the metal electrode film and facing the metal electrode film. The manufacturing method of the transparent conductive substrate of any one of Claims 1.

7. 7. The method for producing a transparent conductive substrate according to 6 above, wherein the protective film is formed using a photolithography method by back exposure using the metal electrode film as a light shielding mask.

8. 7. The method for producing a transparent conductive substrate according to 6 above, wherein the protective film is formed using an inkjet method.

9. 9. A transparent conductive substrate manufactured using the method for manufacturing a transparent conductive substrate according to any one of 1 to 8 above.

10. The transparent conductive substrate according to 9 above,
An electrolyte layer provided on the transparent conductive film side of the transparent conductive substrate;
An electrochemical display element comprising: an electrode substrate having an electrode film disposed opposite to the transparent conductive substrate with the electrolyte layer interposed therebetween.

According to the present invention, the metal electrode film is formed in the groove provided on the surface of the transparent insulator, and the metal electrode film protruding outside the groove is removed by polishing, so that the metal electrode film and the transparent insulator are removed. The level difference with the surface can be reduced, and the transparent conductive film formed thereon is not damaged by the level difference. Therefore, a highly reliable transparent conductive substrate having both high transmittance and low resistance can be obtained without complicating the manufacturing process and increasing the cost.

It is a schematic diagram which shows schematic structure of the transparent conductive substrate which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows schematic structure of the transparent conductive substrate which concerns on Embodiment 2 of this invention. It is a cross-sectional schematic diagram which shows schematic structure of the electrochemical display element which concerns on embodiment of this invention. It is a schematic diagram which shows the manufacturing process of the transparent conductive substrate which concerns on Example 1 of this invention. It is a schematic diagram which shows the manufacturing process of the transparent conductive substrate which concerns on Example 2 of this invention.

Hereinafter, a method for producing a transparent conductive substrate, a transparent conductive substrate, and an electrochemical display element according to an embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiment. Further, in all the following drawings, the ratio of dimensions of each component is appropriately changed in order to make the drawings easy to see. In the following description, “transparent” indicates that the transmittance in the visible light region (wavelength 400 nm to 700 nm) is about 70% or more.
(Embodiment 1)
The configuration of the transparent conductive substrate according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1A is a schematic cross-sectional view showing a schematic configuration of the transparent conductive substrate 2 according to Embodiment 1, and FIG. 1B is a schematic plan view showing the shape of a patterned metal electrode film 203.

As shown in FIG. 1A, the transparent conductive substrate 2 includes a transparent substrate 201, a metal electrode film 203, a transparent conductive film 204, a protective film 205, and the like.

The transparent substrate 201 corresponds to the transparent insulator in the present invention, and a lattice-like groove 201a for forming the metal electrode film 203 is formed on the surface thereof. As a material of the transparent substrate 201, a hard material used in an electronic device such as soda lime glass, non-alkali glass, or quartz can be used.

As a method for forming the groove 201a, the resist can be patterned on the surface of the transparent substrate 201 and then formed using an etching method. As a resist patterning method, it can be formed using a direct patterning method such as a screen printing method, a flexographic printing method, an ink jet method, or a photolithography method. The pattern shape of the groove 201a is not limited to a lattice shape, and may be a stripe shape, for example.

As shown in FIG. 1B, the metal electrode film 203 is formed in the groove 201a of the transparent substrate 201 to reduce the resistance of the transparent conductive film 204.

As a method for forming the metal electrode film 203, a metal electrode film 203A described later is formed on the surface of the transparent substrate 201 including the groove 201a, the metal electrode film formed inside the groove 201a is left, and the outside of the groove 201a is formed. The metal electrode film formed in (1) can be patterned by removing it by chemical mechanical polishing. In chemical mechanical polishing, an unnecessary metal electrode film is removed by rubbing the metal electrode film 203A on a polishing cloth through a slurry corresponding to the material of the metal electrode film 203A. At this time, the metal electrode film 203A is chemically treated so that the surface height of the patterned metal electrode film 203 is the same as the surface height of the transparent substrate 201 or lower than the surface height of the transparent substrate 201. It is preferable to perform mechanical polishing.

As a method for forming the metal electrode film 203A, a sputtering method, a vacuum deposition method, an electroless plating method, an electrolytic plating method, or the like can be used. Moreover, you may form combining these methods. For example, a method of forming a base layer using a sputtering method and then thickening the base layer using an electrolytic plating method. As a material for the metal electrode film 203A, Au, Pt, Ag, Cu, Al, alloys thereof, or the like can be used. Details of the method of forming the metal electrode film 203 will be described later.

The transparent conductive film 204 is formed of an inorganic oxide such as tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), or amorphous oxide semiconductor (IGZO). A conductive polymer typified by a polystyrene sulfonate-doped polyethylene dioxythiophene (PEDOT / PSS) can be formed by using a sputtering method or various wet coating methods.

The protective film 205 is formed on the surface of the transparent conductive film 204 opposite to the side in contact with the patterned metal electrode film 203, at a position facing the patterned metal electrode film 203. The film 203 is protected. The protective film 205 is formed by forming a photosensitive resin on the surface of the transparent conductive film 204 and then patterning it using a photolithography method, or using a direct patterning method such as a screen printing method, a flexographic printing method, or an inkjet method using a resin material. Can be used.
(Embodiment 2)
The configuration of the transparent conductive substrate according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2A is a schematic cross-sectional view showing a schematic configuration of the transparent conductive substrate 2 according to the second embodiment, and FIG. 2B is a schematic plan view showing the shape of the patterned metal electrode film 203.

Since the basic configuration of the transparent conductive substrate 2 according to the second embodiment is substantially the same as that of the first embodiment, the description thereof will be omitted, and a transparent insulating film newly provided mainly for forming the metal electrode film 203 will be omitted. 202 will be described.

As shown in FIG. 2A, the transparent conductive substrate 2 includes a transparent substrate 201, a transparent insulating film 202, a metal electrode film 203, a transparent conductive film 204, a protective film 205, and the like.

In the present embodiment, the transparent substrate 201 is made of a flexible plastic as well as a hard material similar to that of the first embodiment used in electronic devices such as soda lime glass, non-alkali glass, and quartz. What was comprised can also be used. Examples of the plastic material include polyethylene terephthalate (PET), triacetyl cellulose (TAC), cellulose acetate propionate (CAP), polycarbonate (PC), polyethersulfone (PES), polyethylene naphthalate (PEN), and polyimide. (PI) or the like can be used, and in order to enhance the characteristics of the substrate composed of these plastic materials, it is preferable to use a surface whose surface is subjected to a known surface coating or surface treatment.

The transparent insulating film 202 corresponds to the transparent insulator in the present invention, and a lattice-shaped groove 202a for forming the metal electrode film 203 is formed on the surface thereof. As a material of the transparent insulating film 202, a photosensitive resin, a UV curable resin, a thermosetting resin, or the like can be used.

As a method for forming the groove 202a, a method in which a photosensitive resin is formed on the surface of the transparent substrate 201 and then patterned using a photolithography method, a UV curable resin, or a thermosetting resin is applied on the surface of the transparent substrate 201. It can be formed using a nanoimprint method or the like in which the resin is coated and then embossed and cured. The pattern shape of the groove 202a is not limited to the lattice shape, as in the case of the first embodiment, and may be, for example, a stripe shape.

The materials and forming methods of the metal electrode film 203, the transparent conductive film 204, and the protective film 205 are substantially the same as those in the first embodiment.

Next, the configuration of the electrochemical display element according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view showing the configuration of the electrochemical display element 1.

As shown in FIG. 3, the electrochemical display element 1 includes a transparent conductive substrate 2, an electrode substrate 3, a scattering layer 5, an electrolyte layer 6, a seal member 7, and the like.

The electrode substrate 3 includes a substrate 301, an electrode film 303 formed on the surface of the substrate 301, and the like.

The substrate 301 can be a transparent substrate such as glass or PET, and the substrate 301 is not necessarily transparent, and a substrate such as stainless foil or polyimide can also be used.

As the electrode film 303, in the case of an ECD element, an electrode having a tin oxide layer doped with antimony on an ITO electrode can be used. In the case of an ED element, a metal electrode such as a silver electrode or a silver palladium electrode can be used.

The ECD element refers to an electrochromic display element that utilizes a reversible change in the light absorption state due to the oxidation-reduction reaction on the surface of the electrode film, and the ED element includes a metal (for example, silver) or a metal in the chemical structure. It refers to an electrodeposition display element that utilizes the deposition of metal on the surface of an electrode film and dissolution in an electrolyte from an electrolyte containing a compound, both of which are electrochemical display elements. The display principle of both ECD elements and ED elements is based on the use of oxidation-reduction reactions on the surface of the electrode film and changes in light absorption by the reactants alone. Such a member is unnecessary, and is a display element that is very advantageous for cost reduction and process saving.

The electrochemical display element 1 includes a transparent conductive substrate 2 on the observation side and an electrode substrate 3 on the non-observation side, and the transparent conductive film 204 of the transparent conductive substrate 2 and the electrode film 303 of the electrode substrate 3 face each other. Are arranged as follows.

In the case of an ECD element, an electrolyte layer 6 having an electrochromic dye is provided between the transparent conductive film 204 and the electrode film 303, and both positive and negative polarities are provided between the counter electrodes (the transparent conductive film 204 and the electrode film 303). By applying this voltage, an oxidation-reduction reaction of the electrochromic dye is performed on the surface of the observation-side electrode (transparent conductive film 204), and the electrochromic coloring state can be switched reversibly. In order to increase the whiteness of the electrolyte layer 6 in a transparent state, metal oxide fine particles such as TiO ₂ and ZnO are dispersed in the electrolyte layer 6 or the metal oxide fine particles are used with a binder such as a water-soluble polymer. The porous scattering layer 5 may be provided.

In the case of an ED element, an electrolyte layer 6 having, for example, silver or a compound containing silver in the chemical structure is provided between the transparent conductive film 204 and the electrode film 303, and a counter electrode (transparent conductive film 204, electrode By applying positive and negative voltages between the films 303), a redox reaction of silver is performed on the surfaces of both electrodes, and the surface of the transparent conductive film 204 is in a reduced black silver state and in an oxidized transparent state. The silver state can be switched reversibly. In this case, as in the case of the ECD element, in order to increase the whiteness of the electrolyte layer 6 in a transparent state, metal oxide fine particles such as TiO ₂ and ZnO are dispersed in the electrolyte layer 6 or the metal A scattering layer 5 in which oxide fine particles are made porous using a binder such as a water-soluble polymer may be provided.

Here, the details of ECD material, ED material, electrolyte, etc. will be described.

[ECD material]
The electrochromic dye used in the electrochemical display element 1 is a compound that changes the light absorption state by accepting electrons, and an organic compound or a metal complex can be used. As the organic compound, a pyridine compound, a conductive polymer, or a styryl compound can be used. Various viologen compounds described in JP-A-2002-328401, dyes described in JP-T-2004-537743, and other known dyes Can be used. Moreover, when using a leuco type | mold pigment | dye, you may use together a color developer or a decoloring agent as needed.

These materials may be applied directly to the surface of the electrode, or in order to more efficiently accept and receive electrons, an oxide semiconductor nanostructure typified by TiO ₂ is formed on the electrode, The electrochromic material may be applied and impregnated by a method such as an ink jet method.

[ED material]
Examples of the silver or silver-containing compound used in the electrochemical display element 1 include compounds such as silver oxide, silver sulfide, metallic silver, silver colloidal particles, silver halide, silver complex compounds, and silver ions. There are no particular limitations on the phase state species such as solid state, solubilized state in liquid, and gas state, and neutral, anionic, and cationic charged state species. It is also possible to use other metals instead of silver.

The concentration of silver ions contained in the electrolyte layer 6 is preferably 0.2 mol / kg ≦ [Ag] ≦ 2 mol / kg. When the silver ion concentration is less than 0.2 mol / kg, a dilute silver solution is obtained, and the driving speed is delayed. When the silver ion concentration is more than 2 mol / kg, the solubility is deteriorated, and precipitation is likely to occur during low-temperature storage.

〔Electrolytes〕
The electrolyte is usually a substance that dissolves in a solvent such as water and the solution exhibits ion conductivity. In the present embodiment, the electrolyte contains a metal or a compound other than the electrolyte. It does not matter.

For the electrolyte layer 6 provided between the transparent conductive film 204 and the electrode film 303, an organic solvent, an ionic liquid, a redox active substance, a supporting electrolyte, a complexing agent, a white scattering material, a polymer compound, or the like is appropriately selected. Composed.

Electrolytes are usually classified into liquid electrolytes and polymer electrolytes. The polymer electrolyte is further classified into a solid electrolyte substantially composed of a solid compound and a gel electrolyte composed of a polymer compound and a liquid electrolyte. From the viewpoint of fluidity, the solid electrolyte has substantially no fluidity, and the gel electrolyte has a fluidity intermediate between the liquid electrolyte and the solid electrolyte.

In the present embodiment, a gel electrolyte can be suitably used. This gel electrolyte has a high viscosity in a room temperature environment and has fluidity. For example, the viscosity at 25 ° C. is 100 mPa · s or more and 1000 mPa. -It is a gel or high viscosity electrolyte of s or less. In addition, the gel electrolyte in this embodiment does not necessarily need to have a characteristic that causes a sol-gel change with temperature. In the present embodiment, a low-viscosity electrolyte may be used. The viscosity of the low-viscosity electrolyte is an electrolyte having a viscosity at 25 ° C. of 0.1 mPa · s or more and less than 100 mPa · s, and is based on the solvent of the electrolyte. The amount of the polymer binder is preferably less than 10% by mass.

Hereinafter, each component of the electrolyte layer 6 will be described.

(Organic solvent)
As the organic solvent used for the electrolyte layer 6, an organic solvent having a boiling point in the range of 120 to 300 ° C. that can remain in the electrolyte layer 6 without causing volatilization after the electrolyte layer 6 is formed can be used. For example, propylene carbonate, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, butylene carbonate, γ-butyl lactone, tetramethyl urea, sulfolane, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, 2- ( N-methyl) -2-pyrrolidinone, hexamethylphosphortriamide, N-methylpropionamide, N, N-dimethylacetamide, N-methylacetamide, N, N-dimethylformamide, N-methylformamide, butyronitrile, propionitrile , Acetonitrile, acetylacetone, 4-methyl-2-pentanone, 2-butanol, 1-butanol, 2-propanol, 1-propanol, acetic anhydride, ethyl acetate, ethyl propionate , Dimethoxyethane, diethoxy furan, tetrahydrofuran, ethylene glycol, diethylene glycol, can be used triethylene glycol monobutyl ether.

Among the above organic solvents, cyclic carboxylic acid esters such as propylene carbonate, ethylene carbonate, and γ-butyl lactone are more preferable.

(Polymer compound)
In order to increase the viscosity of the electrolyte layer 6, a polymer compound is used as a binder. Although it does not specifically limit as a high molecular compound, For example, it selects from a high molecular compound, such as a butyral resin, polyvinyl alcohol, polyethyleneglycol, and a poly vinylidene fluoride, suitably in view of the characteristic of a display element, the viscosity of an electrolyte, etc., and uses it. be able to.

(Metal oxide fine particles)
In order to increase the whiteness by scattering, an inorganic metal oxide is used. Examples of the inorganic metal oxide include titanium dioxide (anatase type or rutile type), barium sulfate, calcium carbonate, aluminum oxide, zinc oxide, magnesium oxide, zinc hydroxide, magnesium hydroxide, magnesium phosphate, hydrogen phosphate. Magnesium, alkaline earth metal salts, talc, kaolin, zeolite, acidic clay, glass and the like can be used.

(Spacer)
The spacer is a spherical fine particle for regulating the gap between the counter electrodes (the transparent conductive film 204 and the electrode film 303). As the spacer, for example, a fine sphere made of glass, acrylic resin, silica, or the like used for a liquid crystal display or the like can be used. The average particle diameter of the spacer is preferably in the range of 10 μm or more and 50 μm or less in order to improve the whiteness due to the dispersion stability in the electrolyte layer 6 and the scattering effect of the metal oxide fine particles dispersed in the electrolyte layer 6.

Returning to FIG. 3, the seal member 7 is formed in an annular shape around the periphery of the electrolyte layer 6, and sealing the electrolyte layer 6 affects the leakage of the electrolyte solution forming the electrolyte layer 6 and the performance of the electrolyte layer 6. In addition to preventing the entry of moisture and oxygen from the outside air, the transparent conductive substrate 2 and the electrode substrate 3 are bonded.

Next, details of the method for manufacturing the transparent conductive substrate 2 will be described using the following examples.

Hereinafter, examples of the transparent conductive substrate 2 according to the embodiment of the present invention will be described.

Example 1
In FIG. 4, the outline | summary of the manufacturing process of the transparent conductive substrate 2 by Example 1 is shown. 4A to 4E, the left diagram is a schematic sectional view, and the right diagram is a schematic plan view. This example is a manufacturing example of the transparent conductive substrate 2 according to the first embodiment.

First, Cr was deposited to a thickness of 100 nm on the surface of a non-alkali glass substrate having a thickness of 0.7 mm using a sputtering method, and then the Cr film was patterned using a photolithography method. Subsequently, the alkali-free glass substrate was etched using the patterned Cr film as a resist, and lattice-like grooves 201a were formed on the surface thereof. Note that buffered hydrofluoric acid (BHF) was used as the etchant. Then, it is immersed in a mixed solution of diammonium cerium (IV) nitrate and nitric acid, the resist (Cr film) is removed, and an alkali-free glass substrate on which lattice-like grooves 201a are formed (FIG. 4A: transparent substrate 201). ). The shape of the groove 201a was a lattice shape having a width of 10 μm, a depth of 2 μm, and a pitch of 200 μm.

Next, a metal electrode film 203A was formed on the surface of a non-alkali glass substrate (transparent substrate 201) on which lattice-like grooves 201a were formed. Cu was used as the material of the metal electrode film 203A. In addition, when the Cu film is directly formed on the surface of the alkali-free glass substrate, the adhesion between the alkali-free glass substrate and Cu is low and the Cu film is easily peeled off. After forming a Cr film with a thickness of 30 nm using a sputtering method, a Cu film was formed with a thickness of 1 μm on the surface of the Cr film using a sputtering method. Thereafter, the Cu film was thickened by electrolytic plating to form a Cu film having a thickness of 4 μm (FIG. 4B: metal electrode film 203A).

Next, the metal electrode film 203A formed outside the groove 201a is removed by chemical mechanical polishing, whereby the metal electrode film 203A is patterned into a lattice-like metal electrode film 203 (FIG. 4 (c1), FIG. 4). (C2)). At this time, the metal electrode film 203A was subjected to chemical mechanical polishing so that the height of the surface of the patterned metal electrode film 203 was 0.1 μm lower than the height of the surface of the transparent substrate 201. In addition, as a chemical mechanical polishing apparatus, an apparatus manufactured by MT Corporation was used. Moreover, as the slurry, applanador, which is a slurry for Cu film manufactured by Seimi Chemical Co., Ltd., was used.

Next, ITO was formed to a thickness of 150 nm by sputtering on the surface of the transparent substrate 201 on which the metal electrode film 203 was formed (FIG. 4D: transparent conductive film 204).

Next, a photosensitive acrylic resin PC403 (manufactured by JSR) is formed to a thickness of 2 μm on the surface of the transparent conductive film 204, and then back exposure (exposure from the transparent substrate 201 side) using the metal electrode film 203 as a light shielding mask. ) To form a protective film 205 at a position facing the metal electrode film 203 on the surface of the transparent conductive film 204, thereby completing the transparent conductive substrate 2 (FIG. 4 (FIG. 4). e)).

The sheet resistance of the obtained transparent conductive substrate 2 was 0.2Ω / □, and the aperture ratio was 90%. In addition, it was confirmed that the transparent conductive film 204 did not show pin poles or cracks even after the paneling process and the panel was completed, and showed good characteristics.

Further, using the obtained transparent conductive substrate 2, a 3.5-inch electrochemical display element 1 (ED element) was manufactured, and its characteristics were measured. The electrode substrate 3 of the electrochemical display element 1 was provided with a TFT array having pixel electrodes (electrode film 303) with a pitch of 200 μm and 150 μm □.

The measurement results are: reflectance: 60%, display density unevenness due to halftone 35% display: ± 5%, and it was confirmed that the display density unevenness was low and good characteristics were exhibited while ensuring high reflectance. . In addition, in the display rewriting operation durability of 10,000 times, not only the function but also the performance was hardly changed, and it was confirmed that high reliability was ensured.

(Comparative Example 1)
First, after forming a Cu film with a thickness of 2 μm on the surface of a non-alkali glass substrate (transparent substrate) having a thickness of 0.7 mm using a sputtering method, patterning is performed using a photolithography method to form a grid-like metal electrode. A film was formed.

Next, in the same manner as in Example 1, ITO was formed to a thickness of 150 nm (transparent conductive film) using a sputtering method on the surface of the transparent substrate on which the metal electrode film was formed, and the transparent conductive substrate was formed. Was completed.

The sheet resistance of the obtained transparent conductive substrate was 0.2Ω / □, and the aperture ratio was 90%, which was the same value as in Example 1. However, there is no groove that regulates the pattern shape of the metal electrode film, and because the patterning of the metal electrode film is performed using an etching method, the variation in the line width of the metal electrode film pattern is large, and the sheet resistance, There was a large variation in the aperture ratio.

Also, using the obtained transparent conductive substrate, a 3.5-inch electrochemical display element (ED element) was manufactured, and its characteristics were measured. The electrode substrate of the electrochemical display element was provided with a TFT array having pixel electrodes (electrode films) with a pitch of 200 μm and 150 μm □.

The measurement results were reflectance: 60%, display density unevenness due to display of halftone 35%: ± 10%, and the reflectance was the same value as in Example 1, but the display density unevenness was that of Example 1. It was bigger than the case. Moreover, damage to the transparent conductive film due to the edge of the metal electrode film (step between the transparent substrate and the metal electrode film) was observed. For this reason, in the display rewriting operation durability of 10,000 times, the metal electrode film touched the electrolytic solution through the damaged portion to corrode, and bubbles were generated inside the panel, making display impossible.

(Example 2)
In FIG. 5, the outline | summary of the manufacturing process of the transparent conductive substrate 2 by Example 2 is shown. 5A to 5E, the left diagram is a schematic sectional view, and the right diagram is a schematic plan view. This example is a manufacturing example of the transparent conductive substrate 2 according to the second embodiment.

First, a UV curable resin was applied at a thickness of 2 μm on the surface of a 0.1 mm thick PES substrate (FIG. 5A: transparent substrate 201), and embossed with a pressure of 0.1 MPa. Thereafter, the transparent insulating film 202 in which the lattice-like grooves 202a were formed was formed by UV irradiation and curing. The shape of the groove 202a was a lattice shape having a width of 2.5 μm, a depth of 2 μm, and a pitch of 100 μm.

Next, a metal electrode film 203A was formed on the surface of the transparent insulating film 202 in which the lattice-like grooves 202a were formed. Cu was used as the material of the metal electrode film 203A. In addition, when a Cu film is directly formed on the surface of the PES substrate, the adhesion between the PES substrate and Cu is low and the Cu film is easily peeled off. Therefore, in this embodiment, a sputtering method is used on the surface of the PES substrate. After depositing Cr with a thickness of 30 nm, Cu was deposited with a thickness of 1 μm on the surface of the Cr film by sputtering. Thereafter, the Cu film was thickened by electrolytic plating to form a Cu film having a thickness of 4 μm (FIG. 5B: metal electrode film 203A).

Next, the metal electrode film 203A formed outside the groove 202a is removed by chemical mechanical polishing, whereby the metal electrode film 203A is patterned to form a lattice-like metal electrode film 203 (FIG. 5 (c1), FIG. 5). (C2)). At this time, the metal electrode film 203A was subjected to chemical mechanical polishing so that the surface height of the patterned metal electrode film 203 was 0.1 μm lower than the surface height of the transparent insulating film 202. In addition, as a chemical mechanical polishing apparatus, an apparatus manufactured by MT Corporation was used. Moreover, as the slurry, applanador, which is a slurry for Cu film manufactured by Seimi Chemical Co., Ltd., was used.

Next, ITO was formed to a thickness of 150 nm on the surface of the transparent insulating film 202 on which the metal electrode film 203 was formed using a sputtering method (FIG. 5D: transparent conductive film 204).

Next, a photosensitive acrylic resin PC403 (manufactured by JSR) is applied to the surface of the transparent conductive film 204 at a thickness of 2 μm at a position facing the metal electrode film 203 on the surface of the transparent conductive film 204 using an inkjet method. Thus, the protective film 205 was formed, and the transparent conductive substrate 2 was completed (FIG. 5E).

The sheet resistance of the obtained transparent conductive substrate 2 was 0.2Ω / □, and the aperture ratio was 90%. In addition, no pin poles or cracks were observed in the transparent conductive film 204 even after the paneling step and after the panel was completed, and it was confirmed that the same characteristics as in Example 1 were exhibited.

As described above, in the transparent conductive substrate 2 according to the embodiment of the present invention, the metal electrode film 203 is formed in the grooves (201a, 202a) provided on the surface of the transparent insulator (transparent substrate 201, transparent insulating film 202). I tried to do it. Thereby, in order to ensure the high transmittance and low resistance of the transparent conductive substrate 2, even when the metal electrode film 203 is thickened, the step between the metal electrode film 203 and the surface of the transparent insulator is reduced. Thus, the transparent conductive film 204 can be prevented from being damaged by the step.

Furthermore, the metal electrode film 203 was patterned using chemical mechanical polishing. Thereby, even if the film thickness is difficult to be finely patterned by the photolithography method, the patterning can be easily performed. Further, by using chemical mechanical polishing, the surface of the metal electrode film 203 can be sufficiently planarized. Thereby, the transparent conductive film 204 can be reliably prevented from being damaged by the metal electrode film 203.

As a result, a highly reliable transparent conductive substrate 2 having both high transmittance and low resistance can be obtained.

Further, if the height of the surface of the metal electrode film 203 is made lower than the height of the surface of the transparent insulator (transparent substrate 201, transparent insulating film 202), the transparent conductive film 204 is formed by the surface of the metal electrode film 203. Can be prevented from being damaged.

Further, when a transparent substrate made of a hard material such as soda lime glass, non-alkali glass, quartz, or the like is used as the transparent insulator (transparent substrate 201), an etching method is used to form the groove 201a. The groove 201a can be formed with high accuracy. As a result, the metal electrode film 203 can be patterned with high accuracy.

Further, when a photosensitive resin, a UV curable resin, a thermosetting resin, or the like is used as the transparent insulator (transparent insulating film 202), the groove 202a having a fine shape can be formed by using the nanoimprint method for forming the groove 202a. Even so, it can be formed with high accuracy. As a result, the metal electrode film 203 can be patterned with higher accuracy.

Further, when the pattern shape of the metal electrode film 203 is formed in a lattice shape or a stripe shape, the surface potential of the transparent conductive film 204 in contact with the metal electrode film 203 becomes substantially uniform, and uneven display density can be suppressed. In addition, high transmittance can be obtained.

Further, a protective film 205 is formed on the surface of the transparent conductive film 204 opposite to the side in contact with the patterned metal electrode film 203, at a position facing the patterned metal electrode film 203. did. Thereby, even if the transparent conductive film 204 is damaged by the metal electrode film 203, the metal electrode film 203 does not touch the electrolytic solution (electrolyte layer 6) by the protective film 205, and the metal electrode film 203 is corroded. Etc. can be prevented.

Further, when the protective film 205 is formed using a photolithography method by back exposure using the patterned metal electrode film 203 as a light shielding mask, a new light shielding mask is not required and alignment is not required. Thereby, the process can be simplified and the shape of the protective film 205 can be easily matched to the shape of the metal electrode film 203.

Further, when the protective film 205 is formed by using an ink jet method, the utilization efficiency of the protective film material can be increased, so that the manufacturing cost can be reduced.

Further, by using the transparent conductive substrate 2 manufactured in this way as the observation side substrate of the electrochemical display element 1, even when the display area is enlarged, display density unevenness can be suppressed and high reliability can be achieved. Sex can be obtained.

DESCRIPTION OF SYMBOLS 1 Electrochemical display element 2 Transparent conductive substrate 201 Transparent substrate 202 Transparent insulating film 203 Metal electrode film 204 Transparent conductive film 205 Protective film 3 Electrode substrate 301 Substrate 303 Electrode film (pixel electrode)
5 Scattering layer 6 Electrolyte layer 7 Seal member

Claims (10)

Forming a groove on the surface of the transparent insulator;
Forming a metal electrode film on the surface of the transparent insulator including the groove;
Removing the metal electrode film formed outside the groove by polishing;
Forming a transparent conductive film on the surface of the transparent insulator including the metal electrode film formed in the groove, and producing a transparent conductive substrate. The height of the surface of the metal electrode film formed inside the groove is the same as the height of the surface of the transparent insulator or lower than the height of the surface of the transparent insulator. Item 2. A method for producing a transparent conductive substrate according to Item 1. 3. The method for manufacturing a transparent conductive substrate according to claim 1, wherein the groove is formed by using an etching method. The method for producing a transparent conductive substrate according to claim 1 or 2, wherein the groove is formed using a nanoimprint method. The method for manufacturing a transparent conductive substrate according to any one of claims 1 to 4, wherein the groove has a lattice shape or a stripe shape. 6. The method according to claim 1, further comprising a step of forming a protective film on the surface of the transparent conductive film opposite to the side in contact with the metal electrode film and facing the metal electrode film. The manufacturing method of the transparent conductive substrate of any one of these. The method for producing a transparent conductive substrate according to claim 6, wherein the protective film is formed using a photolithography method by back exposure using the metal electrode film as a light shielding mask. The method for producing a transparent conductive substrate according to claim 6, wherein the protective film is formed using an inkjet method. A transparent conductive substrate manufactured using the method for manufacturing a transparent conductive substrate according to any one of claims 1 to 8. The transparent conductive substrate according to claim 9,
An electrolyte layer provided on the transparent conductive film side of the transparent conductive substrate;
An electrochemical display element comprising: an electrode substrate having an electrode film disposed opposite to the transparent conductive substrate with the electrolyte layer interposed therebetween.

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