JP2001118423A - Coating for use in formation of transparent conductive film, transparent conductive film formed therefrom, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive film, and a display device having the transparent conductive film formed on a display surface, which film is high in transparency, excellent in electromagnetic wave shielding effect and antistatic effect, natural in transmission image or color of reflected light, and excellent in durability such as salt resistant. SOLUTION: A transparent conductive film has a conductive layer 2 formed by applying a transparent conductive film-forming coating containing agglomerates of metallic granules. Also, a display device of the present invention includes a transparent conductive film 5 formed on a display surface 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint for forming a transparent conductive film, a transparent conductive film, and a display device, and more particularly to an excellent antistatic effect and an excellent electromagnetic shielding effect when used on a display surface of a cathode ray tube or a plasma display. The film has a high visible light average transmittance, a natural hue of the transmitted image, and a transparent conductive film having excellent durability such as salt water resistance, oxidation resistance, and ultraviolet resistance. Paint for forming a conductive film, a transparent conductive film formed by applying the paint for forming a transparent conductive film,
And a display device having the transparent conductive film formed on a display surface.

[0002]

2. Description of the Related Art A cathode ray tube currently used as a TV cathode ray tube or a display of a computer is a red cathode ray tube.
Characters and images are projected on the display surface by projecting an electron beam on a phosphor screen that emits green and blue light.In addition, static electricity generated on this display surface causes greetings to adhere and reduces visibility, There is a concern that the environment may be affected by radiating electromagnetic waves. In recent years, plasma displays, which are being applied as wall-mounted televisions,
It has been pointed out that static electricity may be generated and electromagnetic waves may be emitted.

In order to solve these problems, conventionally, a coating liquid in which fine particles such as silver and gold are uniformly dispersed in a liquid is applied to the display surface of a display device and dried, or a sputtering method or a vapor deposition method is used. A conductive transparent metal thin film is formed by a method, and a transparent layer having a different refractive index is laminated on an upper layer and / or a lower layer of the transparent metal thin film so as to shield electromagnetic waves, prevent charging, and prevent reflection. . For example, JP-A-8-77832
In the publication, as a transparent conductive film having an excellent electromagnetic wave shielding effect and an antireflection effect, a conductive layer made of metal fine particles containing at least silver having an average particle diameter in a range of 2 nm to 200 nm, and a transparent layer having a different refractive index from the conductive layer. Have been proposed.

[0004]

However, in these methods, the conductivity of the transparent conductive film is not always sufficient, and 400 nm to 500 nm depending on the light transmission spectrum of silver.
Absorption occurs in the transmitted light, the conductive film is colored yellow, the hue of the transmitted image changes unnaturally, and the unevenness of the transmitted color due to the film thickness distribution due to the low average visible light transmittance of the film is low. The problem is that it is noticeable and deteriorates productivity, and the problem is that in a salt mist environment, the surface resistance of the conductive film increases and the electromagnetic wave shielding effect decreases, so that the durability decreases in places that are easily affected by salt mist such as coasts. Was not resolved. The present invention has been made in order to solve the above-described problems, and therefore, has as its object an excellent conductivity that provides an electromagnetic wave shielding effect and an antistatic effect, a high average visible light transmittance of a film, and high transmission image quality. A hue is natural, a transparent conductive film forming paint capable of forming a transparent conductive film having excellent durability represented by salt water resistance, a transparent conductive film formed using the transparent conductive film forming paint, and An object of the present invention is to provide a display device in which a transparent conductive film is formed on a display surface.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a paint for forming a transparent conductive film, which contains at least an aggregate of metal fine particles as a conductive material. Is within the range of 1 nm to 100 nm, and the particle size of the massive aggregate is within the range of 30 nm to 500 nm. In the above, the metal fine particles contain at least silver fine particles and palladium fine particles, and the compounding ratio of the silver fine particles and the palladium fine particles is in the range of 10% by weight to 90% by weight of silver fine particles: 90% by weight to 10% by weight of palladium fine particles. It is preferred that

The present invention also provides a transparent conductive film having a conductive layer formed by applying the coating material for forming a transparent conductive film. In the above, the thickness of the conductive layer is from 5 nm to
Preferably it is within the range of 500 nm. Further, it is preferable that at least one transparent layer having a different refractive index from the conductive layer is laminated on the upper layer and / or the lower layer of the conductive layer. These transparent conductive films have an average visible light transmittance of 70% or more and a surface resistance of 1 × 10 ⁴ Ω / □.
The following is preferred. The present invention further provides a display device in which 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. FIG. 1 is a partial sectional view of a preferred display device of the present invention. In this display device, a conductive layer 2, a transparent layer 3, and a transparent layer 4 having irregularities on the outermost layer (hereinafter referred to as “irregular layer”) 4 are sequentially laminated on the display surface 1. 2, transparent layer 3, and uneven layer 4
Form the transparent conductive film 5 of the present invention.

The present inventors have eagerly studied a transparent conductive film formed by applying a paint containing metal fine particles in order to impart an excellent antireflection effect and an electromagnetic wave shielding effect to the display surface 1 of the display device. As a result of the research, especially the particle size is 1 nm
The conductive layer is formed by using a coating material containing metal fine particle aggregates (hereinafter, referred to as “lumpy aggregates”) in which metal fine particles in the range of 100 nm to 100 nm are aggregated in a lump and having a particle size in the range of 30 nm to 500 nm. Forming No. 2 has led to the present invention by finding that a transparent conductive film 5 having higher conductivity and transparency can be produced than when the metal fine particles are uniformly and independently dispersed.

Hereinafter, the present invention will be described in more detail. In the transparent conductive film 5 of the present invention, the conductive layer 2 is formed using a coating material in which a massive aggregate of metal fine particles is uniformly dispersed as a whole, and is a thin film having a thickness of 5 nm to 500 nm. Regardless, the surface resistance value is 1 × 10 ⁴ Ω / □
It has a high electrical conductivity of at most 70% and an average transmittance of visible light of at least 70%, and in some cases, at least 80%.

The reason why the conductive layer 2 has a high conductivity and a high light transmittance is not necessarily clear, but the conductive agglomerate has a low contact electric resistance as compared with the independently dispersed fine particles. By baking, a much better conductive path is formed with a small number of fine particles, and light transmission is also improved by forming a large mesh gap as compared with a uniform dispersion layer of independently dispersed fine particles. it is conceivable that.

It is particularly important that the particle size of the individual metal fine particles forming the massive aggregate is in the range of 1 nm to 100 nm. If the particle diameter of each metal fine particle is less than 1 nm, the properties as a metal are impaired and the conductivity is reduced, and if it exceeds 100 nm, it is difficult to obtain a lump aggregate.

As fine metal particles used for the conductive layer 2, noble metal fine particles such as gold, silver, palladium, ruthenium, platinum, rhodium, iridium and osmium and fine metal particles such as copper and nickel are effective. In particular, it is preferable to use silver and palladium in combination. That is, silver is relatively easily and inexpensively available as a colloidal dispersion, and has high conductivity and excellent antistatic properties and electromagnetic wave shielding properties. It is effective when it is desired, and when used in combination with palladium, the chemical stability is increased and practically sufficient durability can be obtained. In consideration of conductivity and chemical stability, the mixing ratio of silver and palladium is preferably in the range of 10% by weight to 90% by weight of silver fine particles: 90% by weight to 10% by weight of fine palladium particles.

As schematically shown in FIGS. 2A and 2B,
The aggregate of metal fine particles is formed by aggregating and connecting a plurality of metal fine particles in a lump. For example, as shown in FIG. 2A, metal fine particles (primary particles) 6 having a particle size of 1 nm to 5 nm are aggregated in a lump. As a result, aggregates (secondary particles) 7 having a particle diameter of 100 nm to 150 nm or metal fine particles 6 having a particle diameter of 20 nm to 50 nm aggregated in a lump as shown in FIG. Any of the above-mentioned aggregates 7 may be used, but the particle diameter of the metal fine particles 6 is 1 nm.
-100 nm, and the particle size of the massive aggregate 7 is 3
0 nm to 500 nm, more preferably 70 n
Those having a range of m to 300 nm are preferable from the viewpoint of conductivity and transparency. If the particle size of the agglomerate is less than 50 nm, the electrical resistance between the particles increases, and sufficient conductivity cannot be obtained. If it exceeds 500 nm, the degree of light scattering increases and the transparency of the coating film may be impaired. .

When the coating material containing the agglomerates is applied to a substrate, dried and baked at a temperature in the range of 100 ° C. to 1000 ° C., the contact electric resistance between the particles can be suppressed to a small value. Even when the conductive layer 2 is a thin film having a thickness of 5 nm to 500 nm, high conductivity with a surface resistance of 1 × 10 ⁴ Ω / □ or less can be obtained. As a result, the antistatic effect and the electromagnetic wave shielding effect are excellent, and the visible light average is high. It is possible to obtain a transparent conductive film having a high transparency of 70% or more and having less noticeable unevenness in film thickness.

In producing a paint containing the above-mentioned massive aggregate (hereinafter referred to as “the present paint”), first, a dispersion containing the above-mentioned massive aggregate is prepared. The dispersion of the aggregates can be prepared by various methods, and preferable methods include, for example, a desalting method, a heat treatment method, and a mixing method. The dispersion liquid of metal fine particles (primary particles) used in these methods is prepared by a known method, for example, a method of finely pulverizing metal and dispersing it in a medium, or a method of forming metal fine particles in a medium by forming a colloid or the like. can do. Hereinafter, a method for preparing a typical bulk aggregate dispersion will be described.

Desalting method: Lumpy aggregates are formed by subjecting a dispersion of metal fine particles to desalting. In the case of performing the desalination treatment, the desalination treatment is performed in a state where one or more kinds of metal fine particles are contained. Specific examples of the desalting treatment method include a method of desalting the fine metal particle dispersion with a dialysis membrane, and a method of desalting the fine metal particle dispersion by ultrafiltration. The particle size of the aggregates can be adjusted by the desalting method and the desalting amount, and a suitable desalting method and desalting method can be selected in advance by experiments.

Heat treatment method: A lump-shaped aggregate is obtained by heat-treating a dispersion of fine metal particles at a temperature of 50 ° C. or higher. In this heat treatment method, the particle size of the aggregates can be adjusted by the heat treatment time, the temperature, the mixing ratio of the dispersion medium, and the like, and suitable conditions can be selected in advance by experiments. When a mixed dispersion medium containing 5% by weight to 95% by weight of water, 5% by weight to 95% by weight of an alcohol, and 1% by weight or more of a cellosolve-based solvent is used as a dispersion medium for forming a massive aggregate, It is preferable that the aggregate can be easily formed.

Mixing method: A lump aggregate is obtained by mixing an alcohol, water and a cellosolve-based solvent into a metal fine particle dispersion. In this mixing method, the particle size of the aggregates can be adjusted by the mixing ratio of the mixed dispersion medium, the mixing order, the charging speed, the temperature, the pH, the stirring speed, and the like, and suitable conditions can be selected in advance by experiments. . When a mixed dispersion medium containing 5% to 95% by weight of water, 5% to 95% by weight of an alcohol, and 1% by weight or more of a cellosolve-based solvent is used as a dispersion medium, a lump aggregate is easily formed. This is preferable.

The display device of the present invention is obtained by applying at least the present coating material, and preferably has a thickness of 5 nm to 500 nm.
A transparent conductive film 5 having a conductive layer 2 within the range of nm is formed on the display surface 1. Since the visible light average transmittance of the transparent conductive film 5 is 70% or more and the absorption at a specific wavelength is small, the hue of the transmitted image is not impaired.
Moreover, the excellent antistatic effect and the electric field shielding effect, which are the objects of the present invention, are obtained, and they have a practically sufficient level of resistance to salt water, and because of their high light transmittance, the film thickness unevenness of the coating film. Will also be inconspicuous.

The conductive layer 2 includes, in addition to the agglomerates described above,
Silica fine particles having an average particle diameter of 100 nm or less may be contained in the range of 1% by weight to 60% by weight with respect to the aggregate. The conductive layer 2 obtained by applying the coating material for forming a transparent conductive film containing silica fine particles and forming a film has remarkably improved film strength and improved scratch strength. Further, by containing silica fine particles in the conductive layer 2, the upper layer and / or
Alternatively, when one or more transparent layers 3 having a refractive index different from the refractive index of the conductive layer are provided in the lower layer, the adhesion between the two layers is improved because the transparent layer 3 has good wettability with the silica binder component. There is also an effect of improving, and the scratch strength can be further improved. The silica fine particles are more preferably contained in the range of 20% by weight to 40% by weight with respect to the lump aggregate from the viewpoint of achieving both improvement in film strength and conductivity.

The conductive layer 2 may include other components such as silicon, aluminum, zirconium, cerium, titanium, and the like, if necessary, for the purpose of improving film strength and conductivity in addition to the above components.
Yttrium, zinc, magnesium, indium, tin,
Oxides such as antimony and gallium, composite oxides or nitrides, especially indium or tin oxides, inorganic fine particles mainly containing a composite oxide or nitride, polyester resin, acrylic resin, epoxy resin, melamine Including organic synthetic resins such as resins, urethane resins, butyral resins, and ultraviolet curable resins, hydrolysates of metal alkoxides such as silicon, titanium, and zirconium, or organic / inorganic binder components such as silicone monomers and silicone oligomers. May be.

In order to apply the present coating composition on a substrate, any of ordinary thin-film coating techniques such as spin coating, roll coating, spray coating, bar coating, dip coating, meniscus coating, and gravure coating can be used. Of these, spin coating is a particularly preferred coating method because a thin film having a uniform thickness can be formed in a short time. After application,
The conductive layer 2 is formed on the surface of the substrate by drying the coating film and baking it at 100C to 1000C.

In determining the content of the aggregates (metal fine particles) and the film thickness in the conductive layer 2, it is necessary to consider the requirement of the electromagnetic wave shielding effect. Generally, in order to exhibit an electromagnetic wave shielding effect in addition to an antistatic effect,
As the conductivity of the transparent conductive film 5, a volume resistivity (ρ) of the order of 10 ³ Ω · cm or less is required. That is, when the volume resistivity (ρ) of the transparent conductive film 5 is as low as possible, electromagnetic waves of a wider range of frequencies can be effectively shielded. In order to satisfy this condition, the conductive layer 2 in the transparent conductive film is required.
Has a thickness of 50 nm or more.
It is preferable to contain 0% by weight or more. When the thickness of the conductive layer 2 is less than 50 nm, or when the content of
When the amount is less than the weight percentage, the conductivity is reduced, and it is difficult to obtain a substantial electromagnetic wave shielding effect. After satisfying the above conditions, the thickness of the conductive layer 2 in the transparent conductive film is 5 in consideration of transparency.
It is preferable that the thickness be not more than 00 nm.

The transparent conductive film 5 of the present invention comprises the conductive layer 2
It is preferable that at least one transparent layer 3 is laminated on the upper layer and / or the lower layer (the upper layer in FIG. 1). The transparent layer 3 preferably has a refractive index different from that of the conductive layer 2. This not only protects the conductive layer 2 but also effectively removes or reduces external light reflection at the interlayer interface of the obtained transparent conductive film 5. Further, since the transparent layer 3 is expected to not only prevent the interface reflection in the multilayer thin film but also protect the surface from external force when used on the display surface of a display device, the transparent coat 3 has a sufficient hard coat property for practical use. It is more preferred to have

The material for forming the transparent layer 3 is, for example, a thermoplastic, thermosetting or photo-electron beam curable resin such as polyester resin, acrylic resin, epoxy resin and butyral resin; silicon, aluminum, titanium, zirconium. And the like. A hydrolyzate of a metal alkoxide such as a silicone monomer or a silicone oligomer may be used alone or in combination.

A particularly preferred transparent layer has a high surface hardness of the film.
And relatively low refractive index_Two It is a thin film of. This S
iO_Two As an example of a material capable of forming a thin film, for example, the following formula M (OR)_mR_n (Where M is Si and R is C₁~ C_FourIn the alkyl group of
And m is an integer of 1 to 4, and n is an integer of 0 to 3.
And m + n is 4), or
A mixture of one or more of the partial hydrolysates
Can be Examples of compounds of the above formula include, in particular,
Traethoxysilane (Si (OC_TwoH_Five) _Four) Is a thin film type
Performance, transparency, bonding with conductive layer, film strength and anti-reflection
It is preferably used from the viewpoint of performance.

As long as the transparent layer 3 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 transparent layer 3 is formed by a method of uniformly applying a coating solution (paint for forming a transparent layer) containing the above-mentioned components and forming a film, similarly to the method used for forming the conductive layer 2. Can be. Application is spin coating, roll coating, spray coating, bar code coating, dip coating, meniscus coating,
Any of the usual thin film coating techniques such as gravure coating can be used. Of these, spin coating is a particularly preferred coating method because a thin film having a uniform thickness can be formed in a short time. After application, the coating film is dried and
The transparent layer 3 is obtained by baking at 0 ° C. to 1000 ° C.

In general, the antireflection ability at the interface between layers in a multilayer thin film is determined by the refractive index and thickness of the thin film and the number of laminated thin films. Therefore, in the transparent conductive film of the present invention, the total of the conductive layer and the transparent layer is also used. By designing the thickness of each of the conductive layer and the transparent layer in consideration of the number of stacked layers, an effective anti-reflection effect can be obtained. In a multilayer film having antireflection ability,
When the wavelength of the reflected light to be prevented is λ, if the antireflection film has a two-layer structure, the high refractive index layer and the low refractive index are respectively λ / 4, λ / 4, or λ / By setting the optical film thickness to 2, λ / 4, reflection can be effectively prevented. In the case of a three-layer antireflection film, the order of λ in the order of a medium refractive index layer, a high refractive index layer, and a low refractive index layer
An optical film thickness of / 4, λ / 2, λ / 4 is effective.

In particular, considering the ease of manufacture and economy, as shown in FIG. 1, an SiO ₂ film having a relatively low refractive index and having a hard coat property (refractive index 1) is formed on the upper layer of the conductive layer 2. .46) is preferably formed with a film thickness of λ / 4.

In the transparent conductive film of the present invention including a conductive layer and one or more transparent layers, the conductive layer and the transparent layer may be baked sequentially or simultaneously. For example, the present paint (a paint for forming a transparent conductive film) is applied to the display surface of a display device, a paint for forming a transparent layer is applied thereon, and after drying, 1
By batch baking at a temperature of 00 ° C. to 1000 ° 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.

As the outermost layer of the transparent conductive film 5, it is preferable to provide a transparent layer (an uneven layer) 4 having irregularities. The uneven layer 4 has an effect of scattering light reflected on the surface of the transparent conductive film 5 and giving excellent antiglare properties to the display surface. As the material of the uneven layer 4, silica is preferable from the viewpoint of the surface hardness and the refractive index. The concavo-convex layer 4 is formed by applying a coating for forming a concavo-convex layer as the outermost layer of the transparent conductive film 5 by the above-described various coating methods, and after drying, simultaneously with or separately from the conductive layer 1 and the transparent layer 2. It can be formed by baking at a temperature of 1000 ° C. In particular, spray coating is suitable as a method of applying the uneven layer 4. The height difference between the concave portion and the convex portion of the unevenness is 5 nm or more and 500 nm.
It is hoped that:

At least one layer of the transparent conductive film 5 of the present invention 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. As this coloring material,
For example, monoazo pigment, quinacridone, iron oxide yellow, disazo pigment, phthalocyanine green, phthalocyanine blue, cyanine blue,
Flavanthrone yellow, diansuraquinolyl red, indanthrone blue, thioindigo bordeaux, perylene orange, perylene scarlet, perylene red 17
8. Perylene maroon, dioxazine violet, isoindoline yellow, nickel nitroso yellow, madder lake, copper azomethine yellow, aniline black, alkali blue, zinc white, titanium oxide, red iron oxide, chrome oxide,
Iron black, titanium yellow, cobalt blue, cerulean blue, cobalt green, alumina white, viridian, cadmium yellow, cadmium red, vermilion, lithopone, graphite, molybdate orange, zinc chromate, calcium sulfate, barium sulfate, calcium carbonate, lead white Organic and inorganic pigments such as ultramarine, manganese violet, emerald green, navy blue, carbon black, and azo dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, quinoline dyes, nitro dyes, and nitroso dyes And benzoquinone dyes, naphthoquinone dyes, naphthalimide dyes and perinone dyes. These coloring materials can be used alone or in combination of two or more.

When a colorant is used, its type and amount 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 within the range of 0.0004 to 0.0969 abs. It is preferable that the amount is as follows. 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 2, the blending amount is preferably 20% by weight or less, particularly preferably 10% by weight or less based on the metal content. If it exceeds 10% by weight, a decrease in conductivity is observed, and if it exceeds 20% by weight, the electromagnetic wave shielding effect is hindered.

In the display device of the present invention, any one of the transparent conductive films 5 described above is formed on the display surface 1. In this display device, since the display surface 1 is prevented from being charged, no greeting or the like adheres to the display surface, and the electromagnetic waves are shielded, so that various electromagnetic wave disturbances are prevented. It is bright, the hue of the transmitted image is natural, the film thickness is uniform, so that the coating unevenness on the display surface is not conspicuous, and the salt water resistance is high, so that the durability is high even in an environment exposed to salt fog. If the transparent layer 3 and / or the uneven layer 4 are formed in addition to the conductive layer 2, an excellent antireflection effect and / or an antiglare effect against external light can be obtained.

[0037]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The following was prepared as a metal fine particle dispersion common to Examples and Comparative Examples. (Silver fine particle dispersion) sodium citrate dihydrate (14
g) and an aqueous solution (60 g) in which ferrous sulfate (7.5 g) is dissolved is maintained at 5 ° C., and silver nitrate (2.5 g) is dissolved.
An aqueous solution (25 g) in which g) was dissolved was added to obtain a red-brown silver sol. The silver sol was washed with water by centrifugation to remove impurity ions to obtain a silver fine particle dispersion. In this silver fine particle dispersion, silver fine particles having a particle size in the range of 1 nm to 10 nm were independently dispersed. (Palladium fine particle dispersion liquid) A palladium fine particle (5 g), a dispersant (1 g), butyl cellosolve (10 g), and water (84 g), which have been subjected to a desalting treatment in advance, are mixed, and dispersed using an ultrasonic disperser to disperse the palladium fine particles. Agent was obtained. In this palladium fine particle dispersant, the particle size is 1 nm to 10 n.
m were independently dispersed. (Coating A 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.

(Example 1) Preparation of the present paint (paint for forming a transparent conductive film) [Coating composition] Silver 0.05% by weight Palladium 0.05% by weight Ethyl cellosolve 5% by weight Butyl cellosolve 10% by weight Methanol 10% by weight Water 74.9% by weight [Formation of Lumped Aggregate] In water (10 ° C.), methanol, the silver fine particle dispersion, the palladium fine particle dispersion, ethyl cellosolve, and butyl cellosolve at 5 ° C. were sequentially taken for 60 minutes. The mixture was added and mixed to prepare a paint of the above composition. In this paint, most of the silver fine particles and the palladium fine particles were agglomerated, and as a result of measurement by a laser Doppler method, were found to be agglomerated aggregates having a particle size in the range of 100 nm to 150 nm.

Film formation The above coating material was applied to the display surface of a cathode ray tube using a spin coater, and after drying, the coating material A for forming a transparent layer was applied to the coating surface similarly using a spin coater. The cathode ray tube of Example 1 having an antireflective transparent conductive film was prepared by placing the CRT in a dryer and baking at 150 ° C. for 1 hour to form a transparent conductive film.

(Example 2) Preparation of this paint [Paint composition] Silver 0.08% by weight Palladium 0.12% by weight Ethyl cellosolve 1% by weight Butyl cellosolve 10% by weight Methanol 50% by weight Water 38.8% by weight Formation of Aggregate] According to Example 1, the present coating material having the above composition was prepared. In this paint, most of the silver fine particles and the palladium fine particles aggregate, and the particle diameter is 150 nm to 200 nm.
It was a massive aggregate within the range of nm.

[0041] Using the film formation above the paint and transparent layer forming coating A, Example 1
In the same manner as in Example 1, a cathode ray tube of Example 2 having a transparent conductive film having antireflection properties was prepared.

Example 3 Preparation of the Present Paint [Paint Composition] Silver 0.18 wt% Palladium 0.12 wt% Ethyl cellosolve 1 wt% Ethanol 83.7 wt% Water 15 wt% [Formation of aggregates] Ethanol at 5 ° C., the silver fine particle dispersion, the palladium fine particle dispersion, and ethyl cellosolve were sequentially added and mixed in water (10 ° C.) in the same manner as in Example 1 to prepare the present coating material having the above composition. did. In this coating material, most of the silver fine particles and the palladium fine particles aggregated to form a lump aggregate having a particle diameter in the range of 100 nm to 150 nm.

[0043] Using the film formation above the paint and transparent layer forming coating A, Example 1
In the same manner as in the above, a cathode ray tube of Example 3 having a transparent conductive film having antireflection properties was prepared.

Comparative Example 1 Preparation of Paint for Forming Transparent Conductive Film The paint composition was the same as in Example 1, and a silver fine particle dispersion, a palladium dispersion, ethyl cellosolve, butyl cellosolve,
Methanol and water are mixed, and the obtained mixed solution is subjected to an ultrasonic dispersing machine (“SONIFIRE 45 manufactured by BRANSON ULTRASONICS”).
0 ") to prepare the coating material for forming a transparent conductive film of Comparative Example 1. In the paint of Comparative Example 1, it was confirmed by TEM observation that the silver fine particles and the palladium fine particles were independently and uniformly dispersed, and almost no aggregate was formed.

The deposited above using a transparent conductive film forming coating in Comparative Example 1 and the transparent layer forming coating A, cathode rays of Comparative Example 1 having a transparent conductive film of anti-reflective treated in the same manner as in Example 1 A tube was created.

Comparative Example 2 Preparation of Paint for Forming Transparent Conductive Film The paint composition was the same as in Example 2, and a silver fine particle dispersion, a palladium dispersion, ethyl cellosolve, butyl cellosolve,
Methanol and water were mixed and treated in the same manner as in Comparative Example 1 to prepare a transparent conductive film forming paint of Comparative Example 2. In the paint of Comparative Example 2, it was confirmed by TEM observation that silver fine particles and palladium fine particles were independently and uniformly dispersed, and almost no aggregates were formed.

[0047] Using the film forming the Comparative Example 2 of the transparent conductive film forming coating and a transparent layer forming coating A, in Comparative Example 2 having a transparent conductive film of anti-reflective treated in the same manner as in Example 1 cathode ray A tube was created.

(Comparative Example 3) Preparation of paint for forming transparent conductive film The paint composition was the same as in Example 3, and a dispersion of silver fine particles, a palladium dispersion, ethyl cellosolve, ethanol and water were mixed. To prepare a coating material for forming a transparent conductive film of Comparative Example 3. In the paint of Comparative Example 3, it was confirmed by TEM observation that silver fine particles and palladium fine particles were independently and uniformly dispersed, and almost no aggregates were formed.

Film formation The cathode ray of Comparative Example 3 having the antireflection transparent conductive film treated in the same manner as in Example 1 using the transparent conductive film forming coating material of Comparative Example 3 and the transparent layer forming coating material A was used. A tube was created.

(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. Film thickness: Measured by SEM observation Surface resistance: "Loresta AP" manufactured by Mitsubishi Chemical Corporation (4-terminal method) Scratch test: Under a load of 1 kg, rub the film surface with the metal part of the tip of a mechanical pencil, and visually check the degree of damage. Evaluation: ○; no scratch △: slightly scratched ×: scratched Transmittance: "Automatic Haze Meter HIII DP" manufactured by Tokyo Denshoku Co., Ltd. Haze: "Automatic Haze Meter HIII DP" manufactured by Tokyo Denshoku Co., Ltd. Transmittance difference: Hitachi The difference between the maximum transmittance and the minimum transmittance in the visible light region was calculated using a “U-3500” type self-recording spectrophotometer (the smaller the difference between the maximum and minimum transmittance in the visible light region, the higher the transmittance. The color becomes flat and the hue of the transmitted image becomes sharp.Especially, at 10% or less, the color of the transmitted image approaches black and has a higher degree of sharpness.) Luminous reflectance: EG & G GAMMASCIENTIFIC "MODEL C-11" Visibility: Low Comprehensive evaluation including performance, reflection color, and transmission color ○: good ○ △; somewhat good, △: acceptable △ ×; somewhat poor ×: poor Film unevenness: visual evaluation of uniformity of appearance color ○: good ○ △; somewhat good Δ: acceptable Δ ×: slightly poor ×: defective The results of the above evaluation tests are shown in Tables 1 and 2.

[0051]

[Table 1]

[Table 2]

From the results shown in Tables 1 and 2, the cathode ray tubes of Examples 1 to 3 formed by applying the present coating material containing a lump of agglomerates of metal fine particles were compared with the conventional uniformly dispersed metal fine particles. It can be seen that the surface resistance is low despite the same film thickness as Comparative Examples 1 to 3 including As a result, the thickness of the conductive layer can be reduced when the surface resistance values are substantially the same, so that the transmittance of the transparent conductive film is excellent and the transparency is high. Further, the transparent conductive film formed using the present coating material was also excellent in scratch resistance. As for the transmittance difference, visibility, and film unevenness, good results equivalent to those of Comparative Examples 1 to 3 including conventional uniformly dispersed metal fine particles were obtained.

[0053]

The transparent conductive film of the present invention has a conductive layer formed by applying a coating material for forming a transparent conductive film containing metal fine particles as agglomerates. The film is excellent in electromagnetic wave shielding effect and antistatic effect even though the thickness of the conductive layer is extremely thin and thus the average visible light transmittance is high, especially when a massive aggregate of silver fine particles and palladium fine particles is used. Means that the hue of the transmitted image is natural and the durability is excellent, represented by salt water resistance. Therefore, the display device of the present invention in which this transparent conductive film is formed on the display surface has a natural hue of the transmitted image, has excellent antistatic properties, electromagnetic wave shielding properties and durability, and has high light transmittance. Therefore, the transmitted image is bright, and the film thickness unevenness of the coating film is not conspicuous.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing one embodiment of a display device of the present invention.

FIGS. 2 (a) and 2 (b) are conceptual diagrams schematically showing a lump aggregate of metal fine particles.

[Explanation of symbols]

 1: Display surface 2: Conductive layer 3: Transparent layer 4: Uneven layer 5: Transparent conductive film 6: Fine metal particles 7: Lumped aggregate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 1/22 H01B 1/22 A 5G435 5/14 5/14 A H01J 5/08 H01J 5/08 29 / 28 29/28 29/88 29/88 (72) Inventor Yasunori Kunimitsu 585 Tomicho-cho, Funabashi-shi, Chiba Pref.Sumitomo Osaka Cement Co., Ltd. Sumitomo Osaka Cement Co., Ltd. New Materials Division (72) Inventor Atsumi Wakabayashi 585 Tomimachi, Funabashi-shi, Chiba Pref.Sumitomo Osaka Cement Co., Ltd. New Materials Division F-term (reference) 4J038 EA011 HA066 KA20 NA01 NA20 5C032 AA02 AA07 DD02 DE01 DF02 DF03 DG01 DG02 5C036 BB10 5G301 DA02 DA03 DA11 DD02 5G307 FA01 FB02 FC02 FC10 5G435 AA14 CC12 GG32 GG33 HH02 HH12 KK07 LL04 LL08

Claims (7)

[Claims] 1. A coating material for forming a transparent conductive film containing at least an aggregate of metal fine particles as a conductive material, wherein the particle size of the metal fine particles is in a range of 1 nm to 100 nm, and A paint for forming a transparent conductive film, having a diameter in the range of 30 nm to 500 nm. 2. The metal fine particles contain at least silver fine particles and palladium fine particles, and the mixing ratio of the silver fine particles and the palladium fine particles is 10% by weight to 90% by weight of silver fine particles: 90% by weight to 10% by weight of palladium fine particles. %. The coating for forming a transparent conductive film according to claim 1, wherein the content is within the range of%. 3. A transparent conductive film having a conductive layer formed by applying the coating material for forming a transparent conductive film according to claim 1 or 2. 4. The conductive layer has a thickness of 5 nm to 500 nm.
The transparent conductive film according to claim 3, wherein 5. The transparent film according to claim 3, wherein at least one transparent layer having a refractive index different from that of the conductive layer is laminated on an upper layer and / or a lower layer of the conductive layer. Conductive film. 6. The visible light average transmittance is 70% or more,
The transparent conductive film according to claim 3, wherein the transparent conductive film has a surface resistance of 1 × 10 ⁴ Ω / □ or less. 7. A display device, wherein the transparent conductive film according to claim 3 is formed on a display surface.