JP2000357414A - Transparent conductive film and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize good transparent on a display surface, electromagnetic wave shielding or antistatic effect, weather resistance such as salt-water resistance, scratch resistance, and visibility having no irregularity of natural color phases and island-like aggregation on a transmissive image, by including gold, silver, and one ore more platinum group metal as micro particles in conductive layer. SOLUTION: This film preferably contains 20-70 wt.% gold, 10-40 wt.% silver, and 10-40 wt.% platinum-group metal such as Pd or Ru having good conductivity and economical efficiency, total content of gold and silver with a low specific resistance value is not less than 60 wt.%, and content of silver with relatively low chemical stability is not more than 40 wt.%. The platinum-group metal with low resistance and controllable refractive index is stable in dispersion of micro particle, and suppresses island-like aggregation in the film. Preferably, at least part of micro particles with 1-10 nm grain size form chain-like aggregates with 5-200 nm length, contact resistance between metal particles of a network structure where the aggregates are entangled is low, and light easily passes through the network. Coating having dispersed these particles is applied to a base material to form a conductive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent conductive film and a display device having the transparent conductive film formed on a display surface, and particularly to an excellent antistatic effect when used on a display surface of a cathode ray tube or a plasma display. A transparent conductive film that has a natural transmission color that does not give a sense of incongruity in appearance, has less unevenness of the film, and has excellent weather resistance, and displays this transparent conductive film. The present invention relates to a display device formed on a surface.

[0002]

2. Description of the Related Art A cathode ray tube, which is a kind of display device used as a TV cathode ray tube or a computer display, emits an electron beam onto a phosphor screen which emits red, green, and blue light to display characters and images. Is projected on the display surface, and the static electricity generated on the display surface causes dust to adhere to the display surface, lowering the visibility, and radiating electromagnetic waves to affect the environment. Recently, it has been pointed out that a plasma display, which is being applied to a wall-mounted television or the like, may generate static electricity or emit electromagnetic waves.

[0003] In order to solve the problem of electromagnetic wave radiation in these display devices, for example, Japanese Patent Application Laid-Open No. 8-77832 discloses a transparent metal thin film composed of metal fine particles containing at least silver having an average particle diameter of 2 nm to 200 nm. A transparent conductive film comprising transparent thin films having different refractive indices and having both an electromagnetic wave shielding effect and an antireflection effect is described.

[0004]

However, in the above-mentioned conventional method, although an electromagnetic wave shielding effect can be expected, absorption occurs in transmitted light of 400 nm to 500 nm due to the light transmission spectrum of silver, and the conductive film turns yellow. Coloring, the hue of the transmitted image changes unnaturally, the dispersion stability of the coating liquid for forming the transparent metal thin film is poor, and the film is uneven due to island-like aggregates of metal fine particles, and salt water. If immersed in water for more than 3 days, the surface resistance of the conductive film increases and the electromagnetic wave shielding effect decreases, so problems such as caution when using in places susceptible to salt fog, such as coasts, were not solved. . The present invention has been made in order to solve the above-mentioned problems, and therefore, the object thereof is to provide a high transparency, a high electromagnetic wave shielding effect and an excellent antistatic effect, a natural hue of a transmitted image, and a high saltwater resistance. It is an object of the present invention to provide a transparent conductive film having typical weather resistance and free from unevenness due to island-like aggregates of metal fine particles, and a display device having the transparent conductive film formed on a display surface.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a conductive layer containing fine gold particles, fine silver particles and fine white metal particles is formed on the display surface of the display device. In particular, when a transparent conductive film having a conductive layer in which at least a part of these metal fine particles forms a chain aggregate is formed, an excellent antistatic effect and an electromagnetic wave shielding effect are obtained, and the transmitted color is natural. The inventors have found that the film has less unevenness due to aggregation of the metal fine particles in the film than in the case where a conductive layer is formed by dispersing one or two types of metal fine particles, and has reached the present invention.

[0006] Accordingly, the present invention is directed to claim 1, wherein gold,
Provided is a transparent conductive film having a conductive layer containing silver and at least one platinum group metal as fine particles. The conductive layer contains 20% to 70% by weight of gold and 1% of silver as fine particles.
0% to 40% by weight, and 10% to 40% by weight of platinum group metal.
It is preferred that the content be within the range of weight%. It is preferable that at least a part of the fine particles form a chain aggregate. The length of the chain aggregate is preferably in the range of 5 nm to 200 nm. The conductive layer containing the chain aggregate can be formed by applying a coating material in which the chain aggregate of the fine particles is dispersed to a base material. In the above, it is preferable that at least one transparent layer having a different refractive index from the conductive layer is laminated on the upper layer or the lower layer of the conductive layer. The transparent layer may be formed as one or more layers above or below the conductive layer, or both. The present invention also provides a display device according to claim 7, wherein any one of the transparent conductive films is formed on a display surface.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to preferred specific examples. The conductive layer in the transparent conductive film of the present invention contains gold, silver, and at least one platinum group metal as fine particles. That is, the conductive layer may contain each of the at least three kinds of metals as individual fine particles, or may contain fine particles made of an alloy or a composite of any two or more of these metals. Hereinafter, these fine particles are collectively referred to as “metal fine particles”. As the platinum group metal, palladium, ruthenium, platinum, rhodium, iridium, osmium and the like are suitable, and in particular, palladium and ruthenium are excellent from the viewpoint of conductive performance and economical aspects. The conductive layer can be formed, for example, by applying a paint prepared by dispersing the metal fine particles on a base material.

The conductive layer may contain, as fine particles, 20% to 70% by weight of gold, 10% to 40% by weight of silver, and 10% to 40% by weight of a platinum group metal. preferable. The reason is that gold and silver, which have extremely low specific resistances, are contained in a total amount of 60% by weight or more, so that the resistance of the conductive layer can be reduced. On the other hand, the silver content having relatively low chemical stability is low. Since it is suppressed to 40% by weight or less, it has excellent weather resistance represented by salt water resistance, and at the same time, has a relatively low specific resistance value, and enables control of the refractive index of the conductive layer,
By containing 10% by weight to 40% by weight of a platinum group metal having extremely excellent dispersion stability of fine particles in the paint, even if the conductive layer has a thickness of about 10 nm to 30 nm, the surface of the film can be improved. A highly conductive conductive layer having a resistance value of 1 × 10 ³ Ω / □ or less can be obtained. Further, since metal fine particles are hardly aggregated in an island shape in the film, film unevenness is small, and at least an upper layer or a lower layer of the conductive layer is formed. When one transparent layer is formed,
This is because high antireflection performance with a surface reflectance of 1.0% or less can be obtained.

Further, it has been found that when at least a part of the metal fine particles forms a chain aggregate, particularly high conductivity and high light transmittance can be obtained. Although the reason is not necessarily clear, the chain aggregates of the metal fine particles are entangled with each other to form a fine network structure, and the contact resistance between the metal fine particles forming the network is small, so that the conductivity of the entire film is low. It is considered that the fine mesh serves as an opening for transmitting light, and high light transmittance is obtained.

It is preferable that the particle diameter of each of the metal fine particles forming the chain aggregate is in the range of 1 nm to 10 nm. If the particle size of the individual metal fine particles is less than 1 nm, the properties as a metal are impaired and the conductivity is reduced, which is not preferable.
On the other hand, if it exceeds 10 nm, island-like aggregates are likely to be generated and film unevenness is likely to occur.

The length of the chain aggregate is 5 nm to 20 nm.
Preferably, it is within the range of 0 nm. If the length of the chain aggregate is less than 5 nm, the resistance between the particles may increase and sufficient conductivity may not be obtained. If the length exceeds 200 nm, the degree of light scattering may increase and the transparency of the conductive layer may be impaired. There is. From the viewpoint of the transparency of the conductive layer, the thickness is more preferably in the range of 10 nm to 100 nm.

The conductive layer containing the chain aggregate can be formed by applying a coating material in which the chain aggregate of fine metal particles is dispersed to a substrate and forming a film. The coating material for forming a conductive layer in which chain aggregates of metal fine particles are dispersed, for example, when preparing a metal aqueous sol used in preparing the coating material, adjusts the aqueous metal salt solution to pH 5 to pH 7, It is obtained by adding 0.5 to 3 molar equivalents of the reducing agent to the metal ions. If the pH of the aqueous metal salt solution is higher than 7 or the reducing agent is more than 3 molar equivalents during the preparation of the aqueous metal sol, the metal fine particles themselves grow undesirably and precipitate, which is not preferable. If the pH of the aqueous metal salt solution is less than 5 or the amount of the reducing agent is less than 0.5 times the molar equivalent, independently dispersed fine particles are generated or the reduction reaction does not sufficiently proceed, and metal fine particles are hardly generated. It is not preferable.

The conductive layer can be formed by applying the coating material for forming a conductive layer on a substrate and forming a film. As a coating method, any of ordinary thin film forming methods such as spin coating, roll coating, spraying, bar coating, dipping, meniscus coating, and gravure printing can be used. Of these, spin coating is a particularly preferred coating method since a thin film having a uniform thickness can be formed in a short time. After the application, the coating is dried and baked at, for example, 100 ° C. to 1000 ° C. to form a film, whereby the conductive layer is formed on the surface of the substrate.

[0014] In the transparent conductive film of the present invention, the conductive layer may further comprise, in addition to the metal fine particles, silica fine particles having an average particle diameter of 100 nm or less in an amount of 1% by weight to 6% by weight based on the metal fine particles.
It may be contained within the range of 0% by weight. The conductive layer formed by applying the coating material for forming a conductive layer containing silica fine particles together with the metal fine particles has a remarkably improved film strength and improved scratch strength. Further, by containing silica fine particles in the conductive layer, when providing at least one transparent layer having a refractive index different from the refractive index of the conductive layer in the upper or lower layer, the silica-based binder component in the transparent layer and Has an advantage that the adhesion between both layers is improved, and the scratch strength can be further improved.
The silica fine particles are preferably contained in the range of 20% by weight to 40% by weight with respect to the metal fine particles from the viewpoint of achieving both improvement in film strength and conductivity.

In addition to the above-mentioned components, the above-mentioned conductive layer may contain other components if necessary for the purpose of improving film strength and conductivity, for example, silicon, aluminum, zirconium, cerium, titanium, yttrium, zinc, magnesium, indium,
Oxides such as tin, antimony and gallium, composite oxides,
Or nitrides, especially inorganic fine particles mainly composed of indium or tin oxide, composite oxide or nitride, polyester resin, acrylic resin, epoxy resin, melamine resin, urethane resin, butyral resin, ultraviolet curable resin, etc. Organic synthetic resins, silicon, titanium, hydrolysates of metal alkoxides such as zirconium, or silicone monomers, organic / inorganic binder components such as silicone oligomers, etc., as long as the object of the present invention is not impaired. Is also good.

The conductive property of the transparent conductive film necessary for exhibiting the electromagnetic wave shielding effect in addition to the antistatic function is represented by the following equation (1). S = 50 + 10 log (1 / ρf) + 1.7t√ (f / ρ) Formula 1 In the formula, S (dB): Electromagnetic wave shielding effect, ρ (Ω-cm): Volume resistivity of the conductive layer, f (MHz) ): Electromagnetic wave frequency, t (cm): thickness of the conductive layer. Here, the thickness t is 1 μm from the viewpoint of light transmittance.
(1 × 10 ⁻⁴ cm) or less.
If the term including the film thickness t is ignored in Equation 1, the electromagnetic wave shielding effect S can be approximately expressed by Equation 2 below. S = 50 + 10 log (1 / ρf) Equation 2 Here, as the value of S (dB) increases, the electromagnetic wave shielding effect increases.

Generally, the electromagnetic wave shielding effect is S> 60.
Although dB is considered to be excellent, especially for the conductive film on the display surface, an electromagnetic wave shielding effect of S> 80 dB is desired. In addition, since the frequency of the electromagnetic wave to be regulated is generally in the range of 10 kHz to 1000 MHz, the conductivity of the transparent conductive film requires a volume resistivity (ρ) of 10 ⁻³ Ω · cm or less. . That is, the lower the volume specific resistance value (ρ) of the transparent conductive film, the more effectively electromagnetic waves of a wider range of frequencies can be shielded. In order to satisfy this condition, the thickness of the conductive layer in the transparent conductive film should be 10 nm or more, and the metal fine particles should be 10% by weight.
It is necessary to contain the above. If the film thickness is less than 10 nm or the content of the metal fine particles is less than 10% by weight, the conductivity is lowered, and it is difficult to obtain a substantial electromagnetic wave shielding effect.

In the transparent conductive film of the present invention, it is preferable that at least one transparent layer is laminated above or below the conductive layer. The transparent layer preferably has a refractive index different from that of the conductive layer. by this,
Not only can external light reflection at the interlayer interface of the obtained transparent conductive film be effectively removed or reduced, but also the effect of protecting the conductive layer when the transparent layer is formed on the conductive layer. .

Materials for forming the transparent layer include thermoplastic, thermosetting, or photo / electron beam curable resins such as polyester resin, acrylic resin, epoxy resin, and butyral resin; silicon, aluminum, titanium, and zirconium. Hydrolysis products of metal alkoxides such as; silicone monomers or silicone oligomers alone,
Alternatively, they are used in combination.

A particularly preferred transparent layer is a thin film of SiO ₂ having a high surface hardness and a relatively low refractive index. This S
Examples of the material capable of forming a i0 ₂ thin film, for example, in the _{formula, M (OR) m R n} ( wherein, M is Si, R is an alkyl group of C ₁ -C _4, m is 1 And n is an integer of 0 to 3, and m + n is 4.) or a mixture of one or more of partial hydrolysates thereof. As an example of the compound of the above formula, particularly, tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) is preferably used from the viewpoints of thin film forming ability, transparency, bonding with a conductive layer, film strength and antireflection performance. Can be

If the transparent layer can be set to a refractive index different from that of the conductive layer, various resins, metal oxides, composite oxides, nitrides, etc., or precursors capable of producing these by baking, etc. May be included.

The formation of the transparent layer can be carried out by a method of forming a film by uniformly applying a coating solution (paint for a transparent layer) containing the above-mentioned components, similarly to the method used for forming the conductive layer. . For coating, spin coating, roll coating,
Any of ordinary thin film forming techniques such as a spray method, a bar coating method, a dip method, a meniscus coating method, and a gravure printing method can be used. Of these, spin coating is a particularly preferred coating method since a thin film having a uniform thickness can be formed in a short time. After the application, the transparent layer is obtained by drying the coating film and baking it within the range of, for example, 100C to 1000C.

In general, the interlayer interface antireflection performance of a multilayer thin film is determined by the refractive index and thickness of the thin film and the number of laminated thin films. By considering the thickness of each conductive layer and transparent layer in consideration of the above, an effective anti-reflection effect can be obtained. In a multilayer film having antireflection capability, when the wavelength of reflected light to be prevented is λ, 2
In the case of an antireflection film having a layer structure, the high refractive index layer and the low refractive index are respectively λ / 4, λ / 4, λ / 2, λ from the substrate side.
By setting the optical film thickness to / 4, reflection can be effectively prevented. In the case of a three-layer antireflection film, the optical film thicknesses are λ / 4, λ / 2, λ / 4 in the order of the medium refractive index layer, the high refractive index layer, and the low refractive index layer from the substrate side. Is valid.

In particular, in consideration of ease of manufacture and economy, an SiO ₂ film having a relatively low refractive index and having a hard coat property (refractive index: 1.46) is formed on the conductive layer.
Is preferably formed with a film thickness of λ / 4.

In the transparent conductive film of the present invention including the above-mentioned conductive layer and transparent layer, the conductive layer and the transparent layer may be baked sequentially or simultaneously. For example, a paint for forming a conductive layer is applied to the display surface of a display device, a paint for forming a transparent layer is applied thereon, and after drying, for example, 100 ° C. to 1 ° C.
By batch baking at a temperature in the range of 000 ° C., the conductive layer and the transparent layer can be formed at the same time, and a low-reflection transparent conductive film can be formed.

It is preferable to provide a transparent concavo-convex layer having irregularities on the outermost layer of the transparent conductive film. The transparent uneven layer has an effect of scattering light reflected on the surface of the transparent conductive film and giving excellent antiglare properties to the display surface. As a material of the transparent uneven layer, silica is preferable from the viewpoint of surface hardness and refractive index.
The transparent concavo-convex layer is formed by applying a coating for forming a concavo-convex layer to the outermost layer of the transparent conductive film by any of various coating methods, and after drying, at the same time as the conductive layer or the transparent layer, or separately,
It can be formed by baking at a temperature in the range of 00C to 1000C. In particular, as a method of forming the transparent uneven layer,
Spray coating is preferred.

At least one of the transparent conductive films of the present invention
The layer may contain a coloring material. This coloring material is used for improving the contrast of a transmitted image and adjusting the color of transmitted light and reflected light. Examples of this coloring material include, for example, monoazo pigment, quinacridone, iron oxide yellow, disazo pigment, phthalocyanine green, phthalocyanine blue, cyanine blue, flavanthrone yellow, dianthraquinolyl red, indanthrone blue, thioindigo bordeaux, Perylene orange, perylene scarlet, perylene red 178, perylylene maroon, dioxazine violet, isoindoline yellow, nickel nitroso yellow, madake lake, copper azomethine yellow, aniline black, alkali blue, zinc white, titanium oxide, red iron oxide, chrome oxide, Iron black, titanium erotic, cobalt blue, cerulean blue, cobalt green, alumina white,
Viridian, cadmium yellow, cadmium red,
Organic and inorganic pigments such as vermilion, lithopone, graphite, molybdate orange, zinc chromate, calcium sulfate, barium sulfate, calcium carbonate, lead white, ultramarine, manganese violet, emerald green, navy blue, carbon black, and azo dyes, Anthraquinone dye, indigoid dye, phthalocyanine dye, carbonium dye,
Dyes such as quinone imine dyes, methine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, naphthalimide dyes and perinone dyes can be mentioned. These coloring materials can be used alone or in combination of two or more.

The type and amount of the coloring material to be used should be appropriately selected according to the optical film characteristics of the corresponding transparent conductive film. The absorbance A of the transparent thin film is generally represented by the following equation. A = log ₁₀ (I ₀ / I) = εCD where I ₀ is incident light, I is transmitted light, C is color density, D is light distance, and ε is molar extinction coefficient.

When a colorant is used in the transparent conductive film of the present invention, a colorant having a molar extinction coefficient ε> 10 is generally used. The amount of the coloring material varies depending on the molar extinction coefficient of the coloring material used, but the absorbance A of the laminated film or the single-layer film containing the coloring material is 0.0004 to 0.0969 abs.
It is preferable that the amount is within the range of the above. If these conditions are not satisfied, the transparency and / or the antireflection effect will decrease. When the coloring material is blended in the conductive layer, the blending amount is 20% by weight based on the metal content.
Hereafter, it is particularly preferable that the content be 10% by weight or less. 20
If the content exceeds% by weight, a decrease in conductivity is recognized, which impairs the electromagnetic wave shielding effect.

In the display device of the present invention, any one of the transparent conductive films described above is formed on a display surface. Since this display device is prevented from being charged on the display surface, it does not adhere to the image display surface, shields electromagnetic waves, prevents various electromagnetic wave disturbances, and is excellent in light transmittance, so that images can be displayed. It is bright, the hue of the transmitted image is natural, there is no unevenness in the appearance of the display surface, and since it has high salt water resistance, it has high durability even in an environment where it is exposed to salt fog. In addition to the conductive layer,
If the transparent layer and / or the transparent concavo-convex layer is formed, an excellent antireflection effect and / or an antiglare effect against external light can be obtained.

[0031]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. The following were prepared as stock solutions common to the examples and comparative examples. (Aqueous gold sol containing chain aggregate of fine gold particles) An aqueous solution of pH 5.7 containing 0.15 mmol / l chloroauric acid,
Mixing with 15 mmol / l sodium borohydride,
The obtained colloidal dispersion was concentrated to obtain a gold aqueous sol containing a chain aggregate of 0.102 mol / liter of fine gold particles.

(Silver aqueous sol containing silver fine particles) A silver nitrate (2.5 g) was added to a 5 ° C. aqueous solution (60 g) in which sodium citrate dihydrate (14 g) and ferrous sulfate (14 g) were dissolved.
g) was dissolved in an aqueous solution (25 g) having a pH of 5.9,
A reddish-brown silver sol was obtained. The silver sol was washed with water by centrifugation to remove impurity ions, and then pure water was added thereto for 0.1 ml.
A silver aqueous sol containing 85 mol / l of independently dispersed silver fine particles was obtained.

(Aqueous palladium sol containing chain aggregates of fine palladium particles) An aqueous solution of pH 5.7 containing 0.15 mmol / l palladium chloride and 0.15 mmol / l sodium borohydride are mixed. The obtained colloidal dispersion was concentrated to obtain a palladium aqueous sol containing a chain aggregate of 0.102 mol / l palladium fine particles.

(Colloidal silica) "Silica Doll 30" manufactured by Nippon Chemical Industry Co., Ltd. was used. (Paint for forming transparent layer) Tetraethoxysilane (0.8
g), 0.1 N hydrochloric acid (0.8 g), and ethyl alcohol (98.4 g) were mixed to form a uniform solution. (Coating for forming transparent uneven layer) Tetraethoxysilane (3.
0g), 0.1 N hydrochloric acid (10 g), and ethyl alcohol (87.0 g) were mixed to form a uniform solution.

Example 1 Preparation of a paint for forming a conductive layer: 4.5 g of the above gold aqueous sol,
4 g of a silver aqueous sol, 8 g of a palladium aqueous sol, 0.2 g of colloidal silica, 10 g of ethyl cellosolve, and 73.3 g of ethyl alcohol were stirred and mixed. ) To prepare a coating material for forming a conductive layer. The Au / Ag / Pd weight ratio in the paint is 36/32/3
2, fine metal particles / Si0 ₂ weight ratio is 100/20, the observation by a transmission electron microscope results, the average particle diameter of 6nm
Metal fine particles are aggregated in a chain, and the length is 20 to 90 nm.
Met. Film formation: The above-mentioned coating material for forming a conductive layer is applied to the display surface of a cathode ray tube using a spin coater, and after drying, the coating material for forming a transparent layer is applied to the application surface similarly using a spin coater. Put this CRT in a dryer, 150 ℃
For 1 hour to form a transparent conductive film, thereby producing a cathode ray tube of Example 1 having an antireflective transparent conductive film. As a result of observation with a transmission electron microscope,
Chain aggregates of metal fine particles were observed in this transparent conductive film.

(Example 2) Preparation of paint for forming conductive layer: 7 g of aqueous gold sol, 3.5 g of aqueous silver sol, 7 g of aqueous palladium sol, 0.2 g of colloidal silica, 10 g of ethyl cellosolve, 72.3 g of ethyl alcohol Was stirred and mixed, and treated in the same manner as in Example 1 to prepare a coating material for forming a conductive layer. Au in paint
Ag / Pd weight ratio 50/25/25, fine metal particles / S
i0 ₂ weight ratio was 100/20, the result of observation by a transmission electron microscope, the average particle size 6nm of the fine metal particles are aggregated in chain, its length was 30 to 100 nm. Film formation: Using the above-mentioned paint for forming a conductive layer, the same treatment as in Example 1 was carried out to produce a cathode ray tube of Example 2 having an antireflective transparent conductive film. As a result of observation by a transmission electron microscope, chain aggregates of metal fine particles were observed in the transparent conductive film.

(Example 3) Preparation of a paint for forming a conductive layer: 3 g of the gold aqueous sol, 5 g of the silver aqueous sol, 10 g of the palladium aqueous sol, 0.2 g of colloidal silica, 10 g of ethyl cellosolve, and 71.8 g of ethyl alcohol were stirred. The mixture was mixed and treated in the same manner as in Example 1 to prepare a paint for forming a conductive layer. Au / A in paint
g / Pd weight ratio: 24/38/38, fine metal particles / Si
The O ₂ weight ratio was 100/20. As a result of observation with a transmission electron microscope, metal fine particles having an average particle size of 6 nm were aggregated in a chain, and the length was 10 to 80 nm. Film formation: The cathode ray tube of Example 3 having an anti-reflective transparent conductive film was prepared by using the above-mentioned paint for forming a conductive layer and treating in the same manner as in Example 1. As a result of observation by a transmission electron microscope, chain aggregates of metal fine particles were observed in the transparent conductive film.

Example 4 Preparation of paint for forming conductive layer: 4.5 g of the gold aqueous sol, 7 g of the silver aqueous sol, 5 g of the palladium aqueous sol, 0.2 g of colloidal silica, 10 g of ethyl cellosolve, 73.3 g of ethyl alcohol Was stirred and mixed, and treated in the same manner as in Example 1 to prepare a coating material for forming a conductive layer. Au in paint
Ag / Pd weight ratio: 32/50/18, fine metal particles / S
i0 ₂ weight ratio was 100/20, the result of observation by a transmission electron microscope, the average particle size 6nm of the fine metal particles are aggregated in chain, its length was 20 to 90 nm. Film formation: Using the above-mentioned paint for forming a conductive layer, the same treatment as in Example 1 was performed to produce a cathode ray tube of Example 4 having a transparent conductive film having antireflection properties. As a result of observation by a transmission electron microscope, chain aggregates of metal fine particles were observed in the transparent conductive film.

Comparative Example 1 Preparation of paint for forming conductive layer: 7 g of the aqueous silver sol, 6 g of the aqueous palladium sol, and 0.2 g of colloidal silica;
10 g of ethyl cellosolve and 76.8 g of ethyl alcohol
Was stirred and mixed, and treated in the same manner as in Example 1 to prepare a coating material for forming a conductive layer. Ag / Pd weight ratio in paint is 70/3
0, the fine metal particles / Si0 ₂ weight ratio is 100/30, the observation by a transmission electron microscope results, the average particle diameter of 6nm
Metal fine particles aggregate in a chain, the length of which is 10 to 60 nm
Met. Film formation: The cathode ray tube of Comparative Example 1 having an anti-reflective transparent conductive film was prepared by using the above-mentioned paint for forming a conductive layer and treating in the same manner as in Example 1. As a result of observation by a transmission electron microscope, chain aggregates of metal fine particles were observed in the transparent conductive film.

Comparative Example 2 Preparation of paint for forming conductive layer: 15 g of the aqueous gold sol, 2 g of the aqueous silver sol, 0.2 g of colloidal silica, 10 g of ethyl cellosolve, and 72.8 g of ethyl alcohol were stirred and mixed. In the same manner as in Example 1, a coating material for forming a conductive layer was prepared. Au / Ag weight ratio in the coating is 88/12, the fine metal particles / Si0 ₂ weight ratio is 100/20, observation with a transmission electron microscope, the average particle size 6nm of the fine metal particles are aggregated into chains, Its length was 30-100 nm. Film formation: Using the above-mentioned paint for forming a conductive layer, the same treatment as in Example 1 was carried out to produce a cathode ray tube of Comparative Example 2 having an antireflective transparent conductive film. As a result of observation by a transmission electron microscope, chain aggregates of metal fine particles were observed in the transparent conductive film.

Comparative Example 3 Preparation of paint for forming conductive layer: 3 g of aqueous silver sol, 14 g of aqueous palladium sol, and 0.2 of colloidal silica
g, ethyl cellosolve 10 g, ethyl alcohol
8 g was stirred and mixed, and treated in the same manner as in Example 1 to prepare a coating material for forming a conductive layer. Ag / Pd weight ratio in paint is 30
/ 70, the fine metal particles / Si0 ₂ weight ratio is 100/30, the observation by a transmission electron microscope results, the average particle diameter of 6
nm fine metal particles are aggregated in a chain, and the length is 10-80.
nm. Film formation: The cathode ray tube of Comparative Example 3 having an antireflective transparent conductive film was prepared by using the above-mentioned coating material for forming a conductive layer and treating in the same manner as in Example 1. As a result of observation by a transmission electron microscope, chain aggregates of metal fine particles were observed in the transparent conductive film.

(Evaluation Measurement) The performance of the transparent conductive film formed on the cathode ray tube was measured by the following apparatus or method, and the appearance was visually evaluated. Chain structure: Confirmed by TEM observation Film thickness: Measured by SEM observation Surface resistance: "Loresta AP" manufactured by Mitsubishi Chemical Corporation (4-terminal method) Electromagnetic wave shielding property: Calculated by the above formula 1 on the basis of 0.5 MHz Salt water resistance: Salt water immersion 0.5 MHz electromagnetic wave shielding effect after 3 days Scratch test: Under a load of 1 kg, the membrane surface was rubbed with the metal part of the tip of a mechanical pencil, and the degree of scratching was visually evaluated. With transmittance: "Automatic Haze Meter H III DP" manufactured by Tokyo Denshoku Co., Ltd. Haze: "Automatic Haze Meter H III DP" manufactured by Tokyo Denshoku Co., Ltd. Transmission difference: "U-3500" type recording spectrophotometer manufactured by Hitachi, Ltd. The difference between the maximum transmittance and the minimum transmittance in the visible light region was determined. (The smaller the maximum-minimum transmittance difference in the visible light region, the flatter the transmittance, and the sharper the hue of the transmitted image. Particularly, when the difference is 10% or less, the color of the transmitted image approaches black. Luminous reflectance: "MODEL C-11" manufactured by EG & G GAMMASCIENTIFIC Inc. Reflection color: "CR-300" manufactured by Minolta Camera (CIE chromaticity using ClE color system) The distance of the deviation from the white point x = 0.3137, y = 0.3198 in the figure is represented by √ (Δx ² + Δy ² ) using Δx and Δy, whereby the value of √ (Δx ² + Δy ² ) is obtained. Is closer to "0", the reflected color is whiter, that is, it is closer to natural light that is easy on the eyes.) Visibility: Comprehensive evaluation including low reflection performance, reflected color, and transmitted color. : Evaluation of uniformity of appearance color by visual observation: good ×: poor Tables 1 and 2 show the evaluation test results.

[0043]

[Table 1]

[Table 2]

From the results of Tables 1 and 2, it is found that Example 1 in which the transparent conductive film contains three kinds of metal fine particles of gold, silver and palladium.
The cathode ray tubes of Examples 4 to 4 exhibited excellent evaluation results balanced in various characteristics such as electromagnetic wave shielding property, salt water resistance, scratch test, transmittance difference, reflection color, visibility, and film unevenness. On the other hand, Comparative Example 1 in which the transparent conductive film contained two kinds of metal fine particles of silver and palladium at a ratio of 70/30.
Is inferior to Examples 1 to 4 particularly in salt water resistance, reflection color, and visibility, and Comparative Example 2 including two kinds of metal fine particles of gold and silver is particularly inferior to the scratch test and the film unevenness in Examples 1 to 4. Inferior to Example 4, 2 of silver and palladium
Comparative Example 3 containing 30 kinds of metal fine particles at a ratio of 30/70,
In particular, it can be seen that the salt water resistance, the scratch test, and the luminous reflectance are inferior to those of Examples 1 to 4.

[0045]

Since the transparent conductive film of the present invention has a conductive layer containing fine particles of gold, silver and platinum group metals, the display device of the present invention having the transparent conductive film formed on the display surface is provided. Has high transparency of the display surface, excellent electromagnetic wave shielding effect and antistatic effect, natural color of transmitted image,
It has weather resistance represented by salt water resistance, has excellent scratch resistance, and has excellent visibility without unevenness due to island-like aggregates of metal fine particles.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Atsumi Wakabayashi 585 Tomimachi, Funabashi-shi, Chiba F-term (Reference) 4F100 AA20 AA20H AB24A AB25A AR00B AS00A BA02 CC00A DE01A DE10A GB41 JB02 JD08 JG01A JG03 JL09 JN01 JN01A JN01B JN18B JN30 YY00A 4J038 HA066 KA20 NA20 PA07 5C032 AA02 AA07 DD02 DE01 DF01 DF02 DF03 DF04 DG02 5G307 FA01 FB02 FC09 FC10

Claims (7)

[Claims] 1. A transparent conductive film having a conductive layer containing fine particles of gold, silver and at least one platinum group metal. 2. The method according to claim 1, wherein the conductive layer contains, as fine particles, gold in a range of 20% to 70% by weight, silver in a range of 10% to 40% by weight, and a platinum group metal in a range of 10% to 40% by weight. The transparent conductive film according to claim 1, wherein: 3. The transparent conductive film according to claim 1, wherein at least a part of the fine particles form a chain aggregate. 4. The length of the chain aggregate is from 5 nm to 200 nm.
The transparent conductive film according to claim 3, wherein the thickness is in the range of nm. 5. The conductive layer containing the chain-like aggregates is formed by applying a coating material in which the chain-like aggregates of fine particles are dispersed to a substrate. Item 6. The transparent conductive film according to Item 4. 6. The conductive layer according to claim 1, wherein at least one transparent layer having a refractive index different from that of the conductive layer is laminated on an upper layer or a lower layer of the conductive layer. Transparent conductive film. 7. A display device, wherein the transparent conductive film according to claim 1 is formed on a display surface.