JP2002190214A - Transparent conductive film and display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent and excellent antistatic effect, electromagnetic wave shielding effect and antireflection effect, good chemical stability, natural color of transmitted image, and good visibility. Provided is a conductive film and a display device such as a cathode ray tube which does not have a risk of a phosphor being dropped by using the transparent conductive film for a display surface. SOLUTION: The transparent conductive film of the present invention is made of Ru, Au, P
a coating containing at least one noble metal fine particle selected from the group consisting of t and t, and then dried.
A conductive layer obtained by performing a heat treatment at a temperature of ° C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transparent conductive film and a display device using the same, and more particularly to a display surface of a flat panel display such as a cathode ray tube face panel, a plasma display (PDP), and a fluorescent display tube (VFD). It has a transparent and excellent antistatic effect, electromagnetic wave shielding effect and antireflection effect, and has a natural transmitted color that does not give a sense of incongruity even in the appearance of the coating film. The present invention relates to an excellent transparent conductive film and a display device having the transparent conductive film formed on a display surface.

[0002]

2. Description of the Related Art Conventionally, a cathode ray tube, which is a kind of a display device used for a TV cathode ray tube or a computer display, emits an electron beam onto a phosphor screen which emits red, green and blue light. Since characters and images are projected on the display surface, there is a fear that static electricity generated on the display surface causes dust to adhere to the display surface, lower visibility, and radiate electromagnetic waves to adversely affect the environment.
In addition, recently, it has been pointed out that a flat display such as a plasma display, which is being applied as a wall-mounted television, may generate static electricity or emit electromagnetic waves.

[0003] In order to solve these problems,
By forming a transparent metal thin film on the display surface of the display device by sputtering or vapor deposition, or by applying a coating liquid in which conductive particles such as silver are dispersed in the liquid, the transparent conductive film is formed. By forming a film, antistatic and / or electromagnetic wave shielding is achieved. In addition, when these thin films are formed on the display surface, interface reflection occurs and visibility deteriorates. In order to prevent this, the transparent conductive film is formed on the upper and / or lower layers of the transparent conductive film. It has also been practiced to form transparent thin films having different refractive indices.

[0004]

However, although the above-mentioned conventional transparent conductive film can be expected to have an antistatic effect and an electromagnetic wave shielding effect, it has various problems as described below. For example, when silver fine particles are used as the conductive fine particles, the transmitted light of 400
Since absorption occurs at a wavelength of about 500 nm, the conductive film is colored yellow, and the hue of the transmitted image looks unnatural.

In addition, there are problems that the film quality is soft and rubbing is easily caused, and that the dispersion stability of the coating solution is poor and defects due to aggregates of silver fine particles are formed on the coating film. In addition, there is a problem in that, when immersed in a chemical solution or exposed to salt water, the conductive film deteriorates due to low chemical stability, the surface resistance of the conductive film increases, and the electromagnetic wave shielding effect decreases. In addition, when a coating material for forming a conductive film is applied to a cathode ray tube after completion, there is a problem that the phosphor is peeled off or dropped off when heat treatment is performed.

The present invention has been made in order to solve the above-mentioned problems, and is transparent and has excellent antistatic effect, electromagnetic wave shielding effect and antireflection effect, good chemical stability, and It is an object of the present invention to provide a transparent conductive film having a natural hue of a transmitted image and good visibility, and a display device such as a cathode ray tube or the like in which a phosphor is not likely to fall off by using the transparent conductive film on a display surface. .

[0007]

Means for Solving the Problems The present inventors have proposed a transparent conductive material formed by applying a paint containing fine noble metal particles in order to impart excellent visibility and an electromagnetic wave shielding effect to the display surface of a display device. As a result of intensive studies on the film, a temperature of 500 ° C. to 515 ° C. was applied to a thin film formed using a paint in which at least one noble metal fine particle of ruthenium (Ru), gold (Au), and platinum (Pt) was uniformly dispersed. It has been found that the transparent conductive film subjected to the heat treatment in Example 1 has excellent color tone and chemical stability, and furthermore has excellent conductive performance and antireflection performance, and has reached the present invention.

That is, the transparent conductive film of the present invention is applied with a paint containing at least noble metal fine particles, dried, and then
A conductive layer formed by heat treatment at a temperature of 500 ° C. to 515 ° C. is provided. The noble metal is Ru, A
Preferably, at least one selected from u and Pt.

In this transparent conductive film, a paint containing noble metal fine particles, particularly one of Ru, Au, and Pt, is applied on a base material such as a face panel of a cathode ray tube, and dried at 500 ° C.
When the film is formed by baking at a temperature of about 515 ° C., a film having excellent conductivity satisfying not only the conventional antistatic effect but also the electromagnetic wave shielding effect can be obtained. This transparent conductive film also has an antireflection effect and has good chemical stability. Further, the hue of the transmission image is natural and the visibility is good.

Although the reason for this is not always clear, 50
It is presumed that the heat treatment at 0 ° C. to 515 ° C. results in grain growth and improved compactness between the particles, so that high conductive performance can be obtained and excellent chemical stability can be obtained. The conductive film that has been heat-treated at 500 ° C. to 515 ° C. has a U-shaped reflection spectrum. That is, since the difference in the reflectance in the visible light region is small, the reflectance curve is broadened as a result, and the reflected color is a reflection color that is easy on the eyes without emphasizing a specific color, and is closer to natural light. A transmission image having a color tone is obtained.

Here, the heat treatment temperature is set at 500 ° C. to 515 ° C.
The reason is that, when the heat treatment temperature is less than 500 ° C., the fine particles do not proceed to densification and the conductive performance is impaired.
The reflection spectrum has a V-shape, that is, the difference in reflectance in the visible light region is large, and the color of the region with high reflectance is emphasized as the reflection color. As a result, the reflection color is emphasized. This is because the visibility is reduced due to the appearance.
On the other hand, if the heat treatment temperature exceeds 515 ° C., ions are eluted from the glass substrate used for forming the transparent conductive film, so that the conductive film is attacked and the film appearance is deteriorated by whitening due to aggregation of fine particles. This is because the conductivity also decreases.

[0012] On the upper and / or lower layer of the conductive layer,
It is preferable that at least one transparent layer having a different refractive index from the conductive layer is formed. By forming the transparent layer, the anti-reflection performance of the transparent conductive film is improved, and reflection of external light and haze are extremely reduced.

The display device according to the present invention is characterized in that any one of the transparent conductive films is formed on a display surface. In this display device, since the transparent conductive film is formed on the display surface, charging of the display surface is prevented, and no dust or the like adheres to the image display surface. Further, since the electromagnetic waves are shielded, various electromagnetic wave disturbances are prevented. In addition, the image is bright because of excellent light transmittance, the hue of the transmitted image is natural,
The appearance of the display surface is good. In addition, since the chemical stability is good, there are almost no restrictions on handling.

Preferably, the display surface is a display surface of a face panel of a cathode ray tube. In a conventional display device,
For example, when applying a paint for forming a conductive film to a completed cathode ray tube and performing a heat treatment, there is a problem that the phosphor is peeled off or dropped off. Therefore, the heat treatment temperature is preferably lower. On the other hand, when the transparent conductive film is formed only at the stage of the face panel before assembling the cathode ray tube, it is necessary to seal the face panel and the funnel portion using a glass frit at the time of assembling the cathode ray tube. is necessary. Therefore, a material having heat resistance at a temperature of about 500 ° C. is required as a transparent conductive film forming material.

In the case of the present invention, the noble metal fine particles used are sufficiently stable at this level of heat, and are heat-treated at 500 ° C. to 515 ° C. in advance. At this time, heating at about 500 ° C. has no effect on the transparent conductive film.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION One embodiment of the transparent conductive film and the display device of the present invention will be described with preferred specific examples.
The conductive layer in the transparent conductive film of the present invention is made of Ru, Au, P
t is obtained by applying a coating containing at least one type of noble metal fine particles selected from t (a coating for forming a conductive layer), followed by drying, and then performing a heat treatment at a temperature of 500 ° C. to 515 ° C. In addition to having high chemical stability, an image transmitted through this conductive layer has a natural hue and has a good appearance on the display surface.

The particle size of the noble metal fine particles used in the conductive layer forming coating is preferably in the range of 1 nm to 50 nm. Here, the reason for limiting the particle size as described above is as follows.
If the particle size of the noble metal particles is less than 1 nm, the properties as a metal are impaired, and the conductivity is reduced. If the particle size exceeds 50 nm, the tendency of the noble metal particles to coagulate in the coating material becomes strong, making it difficult to form a uniform coating film. This is because Furthermore, when the particle size of the noble metal fine particles is less than 1 nm, an oxide may be generated, and the fusion and densification of the fine particles become insufficient. In addition, if the light absorbency is large and sufficient conductivity is to be obtained, the transparency is lost and the practicality is reduced.

In the transparent conductive film of the present invention, at least one of the layers, for example, the conductive layer and / or the transparent 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 the substance which can be used as the 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, perillylene maroon, dioxazine violet, isoindolin yellow, nickel nitroso yellow, madder lake, Copper azomethine yellow, aniline black, alkali blue, zinc white, titanium oxide,
Red petal, chromium oxide, iron black, titanium erotic, cobalt blue, cerulean blue, cobalt green, alumina white, viridian, cadmium yellow, cadmium red, vermilion, lithopone, graphite, molybdate orange, zinc chromate, calcium sulfate, Organic and inorganic pigments such as barium sulfate, calcium carbonate, lead white, 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, Various dyes such as a quinoline dye, a nitro dye, a nitroso dye, a benzoquinone dye, a naphthoquinone dye, a naphthalimide dye and a perinone dye can be exemplified. These coloring materials can be used alone or in combination of two or more.

The type and amount of the coloring material used can 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 (1). A = log ₁₀ (I ₀ / I) = εCD (1) In the formula (1), I ₀ : incident light, I: transmitted light, C: color density,
D: light distance, ε: molar extinction coefficient.

In the transparent conductive film of this embodiment, a coloring material having a molar absorption coefficient of ε> 10 is generally used. The content of the coloring material varies depending on the molar extinction coefficient of the coloring material to be used, and the absorbance A of the laminated film and / or the single-layer film containing the coloring material is 0.0004 to 0.0969ab.
s. Is preferably within such a range. If these conditions are not met, the transparency and / or
Alternatively, the antireflection effect decreases.

When a coloring material is added to the conductive layer, the amount of the coloring material is not more than 20% by weight, especially
% By weight or less. If it exceeds 20% by weight, a decrease in conductivity is observed.
This is because the electromagnetic wave shielding effect is hindered.

In the transparent conductive film of this embodiment, the conductive layer
In addition to the above-mentioned noble metal fine particles, 1% by weight of silica fine particles having an average particle size of 100 nm or less based on the noble metal fine particles.
It may be configured to be contained within the range of ４０40% by weight. The conductive layer formed by applying the conductive layer forming paint containing the silica fine particles has a remarkably improved film strength and improved scratch strength.

When the conductive layer contains fine silica particles, one or more transparent layers having a refractive index different from the refractive index of the conductive layer are formed in the upper layer and / or the lower layer. Since the layer has good wettability with the silica binder component, there is also an advantage that the adhesion between both layers is improved, and the scratch strength can be further improved. Here, the silica fine particles are more preferably contained in the range of 20% by weight to 40% by weight with respect to the noble metal fine particles from the viewpoint of achieving both improvement in film strength and conductivity.

In addition to the above components, the conductive layer may further contain other components as required for the purpose of improving film strength and conductivity.
For example, oxides, composite oxides, or nitrides of silicon, aluminum, zirconium, cerium, titanium, yttrium, zinc, magnesium, indium, tin, antimony, gallium, etc., especially oxides and composite oxides of indium and tin Or inorganic fine particles containing nitride as a main component, organic synthetic resins such as polyester resin, acrylic resin, epoxy resin, melamine resin, urethane resin, butyral resin, and ultraviolet curing resin, and metal alkoxides such as silicon, titanium, and zirconium. Or an organic / inorganic binder component such as a silicone monomer or silicone oligomer.

As a method of applying the above-mentioned paint for forming a conductive layer containing at least noble metal fine particles on a substrate such as a glass substrate, there are spin coating, roll coating, spraying, bar coating, dip coating, meniscus coating. Law,
Any conventional film coating technique such as gravure printing can be used. Of these, the spin coating method is used for a short time,
In addition, it is particularly preferable because a coating film having a uniform thickness can be easily formed.

The conductive property of the transparent conductive film required to exert an electromagnetic wave shielding effect in addition to the antistatic function is represented by the following equation (2). S = 50 + 10 · log (1 / ρf) + 1.7t√ (fp) (2) In the equation (2), S (dB); electromagnetic wave shielding effect ρ (Ω · cm); volume resistivity of the conductive film f (MHz); electromagnetic wave frequency t (cm); thickness of conductive film.

Here, from the viewpoint of light transmittance, it is preferable that the thickness t is not more than about 1 μm (1 × 10 ⁻⁴ cm). If ignored, the electromagnetic wave shielding effect S can be approximately expressed by the following equation (3). S = 50 + 10 · log (1 / ρf) (3) Here, as the value of S (dB) increases, the electromagnetic wave shielding effect increases.

Generally, the electromagnetic wave shielding effect is S> 60.
If it is dB, it is considered to be excellent. In particular, regarding the conductive film on the display surface, an electromagnetic wave shielding effect of S> 80 dB is desired. Further, 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 is 10 ³ Ω.
A volume specific resistance (ρ) of not more than cm is required.

That is, the lower the volume specific resistance value (ρ) of the transparent conductive film, the more effectively the electromagnetic wave having a frequency in a wider wave number band can be shielded. Therefore, in order to satisfy this condition, it is preferable that the thickness of the conductive layer in the transparent conductive film is 10 nm or more, and the content of the metal and the metal oxide in the conductive layer is 10% by weight or more. . The reason is that when the film thickness is less than 10 nm or the content of the metal and the metal oxide is less than 10% by weight, the conductivity decreases, and it becomes difficult to obtain a substantial electromagnetic wave shielding effect. .

In the transparent conductive film of this embodiment, it is preferable that at least one transparent layer is laminated on the upper and / or lower layer of the conductive layer. This transparent layer preferably has a refractive index different from that of the conductive layer.
This not only protects the conductive layer but also effectively removes or reduces external light reflection at the interlayer interface of the obtained transparent conductive film.

As a material for forming the transparent layer, for example,
Thermoplastic, thermosetting or photo / electron beam curable resins such as polyester resin, acrylic resin, epoxy resin and butyral resin; hydrolyzates of metal alkoxides such as silicon, aluminum, titanium and zirconium; silicone monomers or silicone oligomers Are used alone or in combination.

A particularly preferred transparent layer is a SiO ₂ thin film having a high surface hardness and a relatively low refractive index. This S
Examples of the material capable of forming the iO ₂ thin film include, for example, the following molecular formula: M (OR) _m R _n (where M is Si, R is a C ₁ -C ₄ alkyl group, and m is l And n is 0 or 1-3.
And m + n is 4), or one or more mixtures of partial hydrolysates thereof.

As an example of the compound of this molecular formula, particularly, tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) is used in view of thin film forming property, transparency, bonding property with a conductive layer, film strength and antireflection performance. Is preferably used. The transparent layer,
As long as the refractive index can be set to be different from that of the conductive layer, it may include various resins, metal oxides, composite oxides, nitrides, or the like, or a precursor that can generate these by baking.

The formation of the transparent layer can be carried out in the same manner as the method used for forming the conductive layer by a method in which a coating solution containing the above-mentioned components (paint for forming a transparent layer) is uniformly applied to form a film. . As the coating method, any of ordinary film coating techniques such as spin coating, roll coating, spraying, bar coating, dipping, meniscus coating, and gravure printing can be used. Among them, the spin coating method is particularly preferable because a thin film having a uniform thickness can be easily formed in a short time. After coating, the coating film is dried and baked together with the conductive layer at 500 ° C. to 515 ° C. to obtain a transparent layer.

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 laminations. 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 layer are respectively λ / 4, λ / 4, or λ / 2,
By setting the optical thickness to λ / 4, reflection can be effectively prevented.

In the case of a three-layer antireflection film, an optical film of λ / 4, λ / 2, λ / 4 is formed in the order of the medium refractive index layer, the high refractive index layer and the low refractive index layer from the substrate side. It is effective to make it thick. In particular, considering ease of manufacture and economics,
It is preferable to form an SiO ₂ film (refractive index: 1.46) having a relatively low refractive index and also having a hard coat property with a thickness of λ / 4 on the upper layer of the conductive layer.

In the transparent conductive film of this embodiment including the conductive layer and the transparent layer, the conductive layer and the transparent layer may be baked sequentially or simultaneously. For example, a conductive layer-forming paint is applied to the display surface of a display device, a transparent layer-forming paint is applied thereon, and after drying, the batch is baked at a temperature of 500 ° C. to 515 ° C. to form a conductive layer and a transparent layer. Can be formed at the same time to form a low-reflection transparent conductive film.

It is preferable to provide a transparent layer having irregularities on the outermost layer of the transparent conductive film. The 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 the material of the uneven layer, silica is preferable from the viewpoint of surface hardness and refractive index. This concavo-convex layer is formed by applying a coating for forming a concavo-convex layer as the outermost layer of the transparent conductive film by the same various coating methods as described above, 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 of 0 ° C to 515 ° C. In particular, as a method for applying the uneven layer, a spray coating method is preferably used.

In the display device of this embodiment, any one of the transparent conductive films described above is formed on the 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. Since it is bright, the hue of the transmitted image is natural, the appearance of the display surface is good, and the chemical stability is high, there is almost no restriction in handling. If the transparent layer and / or the uneven layer are formed in addition to the conductive layer, an excellent antireflection effect and / or an antiglare effect against external light can be obtained.

[0041]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. The following stock solutions were prepared as common stock solutions for Examples and Comparative Examples. (Ruthenium aqueous sol) An aqueous solution containing 0.15 mmol / l ruthenium chloride and a 0.024 mmol / l aqueous sodium borohydride solution were mixed, and the obtained colloidal dispersion was concentrated to 0.198 mol. / L of an aqueous sol containing ruthenium microparticles. The average particle size of the ruthenium fine particles was 10 nm.

(Transparent thin film coating) 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. (Colloidal silica) "Silica Doll 30" manufactured by Nippon Chemical Industry Co., Ltd.

Example 1 Preparation of paint for forming conductive layer: 5 g of the above-mentioned ruthenium aqueous sol
10 g of ethyl cellosolve and 85.
0 g was added thereto, followed by stirring and mixing, and the obtained mixture was dispersed by an ultrasonic dispersing machine (“Sonifire 450” manufactured by BRANSON ULTRASONICS) to prepare a coating material for forming a conductive layer.

Film formation: The above-mentioned paint for forming a conductive layer is applied on a face panel of a cathode ray tube using a spin coater.
After drying, the above-mentioned coating material for forming a transparent layer is similarly applied to the application surface using a spin coater, and the face panel is placed in a drier and baked at 500 ° C. for 1 hour to form a transparent conductive film. Thereby, the cathode ray tube of Example 1 having the antireflection transparent conductive film was produced.

(Example 2) Preparation of paint for forming conductive layer: 5 g of the above-mentioned ruthenium aqueous sol
10 g of ethyl cellosolve and 85.
0 g was added thereto, followed by stirring and mixing, and the obtained mixture was dispersed by an ultrasonic dispersing machine (“Sonifire 450” manufactured by BRANSON ULTRASONICS) to prepare a coating material for forming a conductive layer.

The above-mentioned paint for forming a conductive layer is applied to the face panel of a cathode ray tube using a spin coater, and after drying, the above-mentioned paint for forming a transparent layer is applied to the application surface similarly using a spin coater. Then, the face panel was placed in a dryer and baked at 515 ° C. for 1 hour to form a transparent conductive film, thereby producing a cathode ray tube of Example 2 having an antireflective transparent conductive film.

Comparative Example 1 Preparation of paint for forming conductive layer: 5 g of the above aqueous ruthenium sol
10 g of ethyl cellosolve and 85.
0 g was added thereto, followed by stirring and mixing, and the obtained mixture was dispersed by an ultrasonic dispersing machine (“Sonifire 450” manufactured by BRANSON ULTRASONICS) to prepare a coating material for forming a conductive layer.

Film formation: The above-mentioned paint for forming a conductive layer is applied on a face panel of a cathode ray tube using a spin coater.
After drying, the above-mentioned coating material for forming a transparent layer is similarly applied to the application surface using a spin coater, and the face panel is placed in a drier and baked at 490 ° C. for 1 hour to form a transparent conductive film. Thus, a cathode ray tube of Comparative Example 1 having an antireflection transparent conductive film was produced.

Comparative Example 2 Preparation of paint for forming conductive layer: 5 g of the above aqueous ruthenium sol
10 g of ethyl cellosolve and 85.
0 g was added thereto, followed by stirring and mixing, and the obtained mixture was dispersed by an ultrasonic dispersing machine (“Sonifire 450” manufactured by BRANSON ULTRASONICS) to prepare a coating material for forming a conductive layer.

Film formation: The above-mentioned paint for forming a conductive layer is applied on a face panel of a cathode ray tube using a spin coater.
After drying, the above-mentioned coating material for forming a transparent layer is similarly applied to the application surface using a spin coater, and the face panel is placed in a drier and baked at 520 ° C. for 1 hour to form a transparent conductive film. Thereby, a cathode ray tube of Comparative Example 2 having an antireflection transparent conductive film was produced.

(Evaluation Test) The performance of the transparent conductive film formed on the cathode ray tube was tested by the following apparatus or method.
The appearance was visually evaluated. Film thickness: Measured by SEM observation Surface resistance: "Loresta AP" (manufactured by Mitsubishi Chemical Corporation) (four-point needle method) Electromagnetic wave shielding property: Calculated by the above formula (2) on the basis of 0.5 MHz Salt water resistance: 0. 3 days after salt water immersion. 5MHz electromagnetic wave shielding effect

Scratch test: Under a load of 1 kg, the surface of the membrane was rubbed with a metal part of the tip of a mechanical pencil, and the degree of damage was visually evaluated. "Automatic Haze Meter HIII DP" manufactured by Shikisha Haze: "Automatic Haze Meter HIII DP" manufactured by Tokyo Denshoku

Transmittance difference: The difference between the maximum transmittance and the minimum transmittance in the visible light region was determined using a “U-3500” type self-recording spectrophotometer manufactured by Hitachi, Ltd. (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, and the color of the transmitted image becomes higher. Luminous reflectance: “MODEL C-11” manufactured by EG & GAMMASCIENTIFIC

Reflected color: “CR-300” manufactured by Mirta Camera Co., Ltd. (using the CIE color system, the distance from the white point (x = 0.3137, F = 0.3198) in the CIE chromaticity diagram to Δx , (Δx ² + Δy ² ), whereby the closer the value of √ (Δx ² + Δy ² ) to “0”, the whiter the reflection color, that is, the closer to natural light that is easy on the eyes. Visibility: Comprehensive evaluation including low reflection performance, reflection color, and transmission color ○: Good ×: Poor Film defect: Visual small defect evaluation ○: Good ×: Poor

The results of the evaluation test are shown in Tables 1 and 2.

[Table 1]

[0056]

[Table 2]

From the results in Tables 1 and 2, Examples 1 and 2
A film having a surface resistance of 5 × 10 ^{2 to} 7 × 10 ² Ω / □ and an electromagnetic wave shielding property of 81 to 82 dB was obtained, which was excellent in antistatic effect and electromagnetic wave shielding effect. Further, in Examples 1 and 2, the luminous reflectance was low, the reflection color was close to 0, the reflection color was low and the reflection color was close to natural light which was easy on the eyes, and the salt water resistance was excellent and there was no film defect. A strong transparent conductive film was obtained.

On the other hand, in Comparative Example 1, the heat treatment temperature was 490 ° C.
Therefore, the surface resistance value was high, and the electromagnetic wave shielding effect could not be exhibited. In addition, since the luminous reflectance is high and the reflection color is also large, the electromagnetic wave shielding effect becomes insufficient and the visibility becomes insufficient. In Comparative Example 2, since the heat treatment temperature was as high as 520 ° C., the film was attacked by ions eluted from the base material (glass substrate). As a result, not only the resistance value increased, but also the coating film was aggregated. Whitening occurred, resulting in a film with poor visibility.

[0059]

The transparent conductive film of the present invention is coated with a paint containing at least noble metal fine particles, dried, and then dried at 500 ° C.
Since it has a conductive layer that is heat-treated at a temperature of up to 515 ° C., it is possible to obtain transparent and excellent antistatic effect, electromagnetic wave shielding effect and antireflection effect, good chemical stability, and transmission image. Has an effect that the hue is natural and visibility is good.

Since the display device of the present invention has a structure in which the transparent conductive film of the present invention is formed on the display surface thereof, the display surface can be prevented from being charged, and there is a possibility that dust or the like adheres to the image display surface. Absent. Further, since the electromagnetic waves are shielded, various electromagnetic wave disturbances can be prevented. Further, since the light transmittance is excellent, the image becomes bright, the hue of the transmitted image becomes natural, and the appearance of the display surface becomes good. Moreover, since the chemical stability is good, there are almost no restrictions on handling.

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Claims (5)

[Claims] 1. A transparent conductive film comprising a conductive layer formed by applying a paint containing at least noble metal fine particles, drying and then heat-treating the coating at a temperature of 500 ° C. to 515 ° C. 2. The transparent conductive film according to claim 1, wherein the noble metal is at least one selected from ruthenium, gold, and platinum. 3. 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 formed on an upper layer and / or a lower layer of the conductive layer.
The transparent conductive film according to the above. 4. A display device, wherein the transparent conductive film according to claim 1, 2 or 3 is formed on a display surface. 5. The display device according to claim 4, wherein the display surface is a display surface of a face panel of a cathode ray tube.