JPH10212138A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the transimissvity of a colored film even after heat treatment and to obtain a display device having high contrast effect and excellent in color tone regulating property by forming the colored film on the surface of face glass with a coating material contg. fine graphite particles. SOLUTION: When coating films including at least a colored film are formed on the surface of a face panel and heat-treated to produce a display device, the colored film is formed with a coating material contg. 3-60wt.% fine graphite particles of <=0.1μm particle diameter optionally combined with an org. pigment having absorption in a specified wavelength range and a compd. represented by the formula, R<1> n M(OR2 )4-n or a product obtd. by hydrolyzing and condensing the compd. as a binder. In the formula, R<1> is alkyl, alkenyl or aryl, M is Si, Ti, Zr or Al, R2 is alkyl and (n) is 0 or 1. The colored film may be formed as a laminated film by combination with an electrically conductive film contg. Sb doped tin oxide or Sn doped indium oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device having a surface coated with a colored film to form a display surface having a high contrast effect and excellent color tone adjustment.

[0002]

2. Description of the Related Art Conventionally, in a display device such as a cathode ray tube, a liquid crystal display, and a plasma display, a colored film for lowering the transmittance may be formed on the face glass surface for the purpose of high contrast effect and color tone adjustment. Further, the colored film is combined with a conductive film to form a colored conductive laminated film, thereby producing a display device excellent in antistatic, electromagnetic wave shielding effect, high contrast effect, etc.
2-8427, JP-A-5-178623 and the like).

[Problems of the Prior Art] In a conventional display device having a conventional cathode ray tube, a coating in which a coloring agent is mixed is formed on a glass portion outside a phosphor layer, that is, on a face glass portion, and the entire visible light region is formed. The light transmittance is lowered over the entire range to achieve high contrast. In addition, the thickness of the glass is different between the central part and the peripheral part of the panel, and the transmittance changes between the central part and the peripheral part only by coloring the face glass. There is a problem of darkening.

In order to prevent this, a color film is formed on the face panel surface to adjust the color tone.
This is a useful method for correcting the transmittance of the face glass. Incidentally, the above-mentioned colored film is usually applied in the final stage of cathode ray tube production in many cases.

The reason is that a glass bulb used for a cathode ray tube is composed of a panel for displaying an image, a funnel and a neck for forming the background, and the sealing between the panel and the funnel in the manufacture of the cathode ray tube. In the process and the exhaust process for depressurizing the inside of the cathode ray tube,
Because there is a heat treatment step of raising the temperature to 350 to 500 ° C., the transmittance changes at the temperature during the heat treatment, and as a result, the good high contrast effect and color tone adjustment required for the cathode ray tube are impaired.

[0006] For this reason, coating of a colored film can be performed only after completion of the cathode ray tube. However, in order to form a film in the final step, it is necessary to handle a cathode ray tube which is almost completed, so that the workability is poor and a large-scale coating device is required.

Further, when manufacturing a display device having a colored conductive laminated film including a colored film and a conductive film on an image display surface, the conductive film is formed by a CVD method, a thermal decomposition method, a sol-gel method, or the like. In some cases, heat treatment may be performed during the formation of the conductive film. In this heat treatment step, the transmittance of the colored film changes, and the favorable transmittance required for the display device changes, thereby impairing the high contrast effect and color tone adjustment. There was a problem that it had been.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a specific problem for solving the problems is that the transmittance does not change due to a heat treatment step during manufacturing. An object of the present invention is to provide a display device having a colored film.

[0009]

Means for Solving the Problems Claim 1 of the present invention
In the display device according to the above, a coating containing at least a colored film is formed on the face glass surface, and then the colored film is formed by a paint containing graphite fine particles in a display device manufactured through a heat treatment at 350 to 500 ° C. It is characterized by having done.

The display device according to claim 2 is characterized in that the coating containing the colored film is a colored conductive laminated film containing at least a conductive film.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below using a cathode ray tube as an example. However, this embodiment is specifically described for better understanding of the present invention, and does not limit the content of the invention unless otherwise specified.

[Structure] The temperature is 3
There is a heat treatment step of 50 ° C or more and 500 ° C or less. Therefore, the colored film is required to have no change in transmittance before and after the heat treatment step.

Since the graphite fine particles are hexagonal crystals, they have excellent heat resistance, unlike amorphous carbon black used in the prior art, and have a temperature of 350 to 500 ° C.
In the heat treatment step, high contrast and color tone adjustment can be easily achieved without deterioration.
The present invention can be used for a display device having a colored film on the face glass surface.

The transmittance required for the colored film is 50
% Or more and 98% or less. This is because if the transmittance is 49% or less, the brightness of the cathode ray tube is reduced, and if the transmittance is 99% or more, the effect of the colored film is not obtained.

Further, in order to prevent image quality deterioration, a transparent film without light scattering is required. In order to satisfy this, the particle size of graphite particles used must be 0.1 μm
It is desirable that: The reason is that the particle size is 0.1μ
If it is more than m, Rayleigh scattering occurs, causing whitening of the colored film and the colored conductive laminated film, lowering the resolution of the cathode ray tube, and lowering the contrast.

The binder component used in the paint for forming a colored film has a general formula R ¹ nM (OR ² ) _4-n (R ¹ represents an alkyl group, an alkenyl group or an aryl group, and M represents Si, T
a metal such as i, Zr, or Al; R ² represents an alkyl group; n represents an integer of 0 or 1); or a hydrolyzed condensation polymer thereof. Where R ¹ and R
^{When 2} is an alkyl group, they may be the same or different.

Specific examples of the compound represented by the general formula R ¹ nM (OR ² ) _4-n include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, tetraisopropoxytitanium, Butoxyaluminum and the like. These R ¹
nM (OR ² ) _4-n can be used alone or in combination of two or more.

In the hydrolytic condensation polymerization of R ¹ nM (OR ² ) _4-n , as a catalyst, an inorganic acid such as hydrochloric acid, phosphoric acid nitrate, boric acid, formic acid, acetic acid, maleic acid, fumaric acid, propionic acid, Organic acids such as oxalic acid, malonic acid, tartaric acid, and succinic acid; and alkalis such as ammonia and trimethylammonium. Of these, hydrochloric acid and nitric acid are particularly preferably used.

The amount of water used for the hydrolytic polycondensation of R ¹ nM (OR ² ) _4-n is also determined as appropriate, but preferably, R ¹ nM (OR ² ) _4-n is 1 mol. On the other hand, 0.001 ~
It is used in a range of 0.4 mol.

Examples of the solvent used in the paint for forming a colored film of the present invention include alcohols, glycol derivatives, esters, ketones, and ethers. These may be used alone or in combination of two or more. You can also. As alcohols, methanol, ethanol,
n-propyl alcohol, isopropyl alcohol, n
-Butanol, 2-butanol, isobutanol, octanol and the like.

The glycol derivatives include ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol n-propyl ether,
Examples include propylene glycol n-propyl ether, ethylene glycol n-butyl ether, and propylene glycol n-butyl ether.

Examples of the esters include methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate and the like. Ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone and the like. Examples of ethers include ethyl ether, butyl ether, methyl cellosolve, ethyl cellosolve, dioxane, and the like.

In the colored film, in addition to the graphite fine particles,
A colored pigment having an absorption band at a specific wavelength may be contained in a range that does not impair the effect of adding the graphite fine particles. By using the graphite fine particles and the colored pigment together, the high contrast effect can be improved and the color tone can be easily adjusted.

As the colored pigment which can be used in combination with the graphite fine particles, any pigment which has high heat resistance and is not deteriorated by heat treatment can be used. For example, Sn, Cu,
Cr, Fe, Mn, Co, Si, P, Ca, Pb, T
i, Ba, Ni, Sb, Zn, Al, Li, Ag, A
Examples include metals, metal oxides, and organic substances containing at least one element among u, Pt, and Pd. It is desirable that the particle size of the colored pigment is 0.1 μm or less.

Further, in addition to the graphite fine particles, conductive fine particles such as antimony-containing tin oxide, tin-containing indium oxide, gold, silver, platinum and palladium may be contained.
The particle size of the conductive fine particles is desirably 0.1 μm or less. In dispersing the graphite fine particles or the colored pigment, at least one of an anion, a cation, and a nonionic surfactant is used in an amount of about 0.1 to 50% by weight based on the graphite fine particles or the colored pigment.
Further, a dispersion of fine graphite particles or a colored pigment can be obtained by a known dispersion method such as a homogenizer, a sand mill, a ball mill, and ultrasonic waves using the above-mentioned appropriate solvent.

The above-mentioned hydrolyzed polycondensation product of R ¹ nM (OR ² ) _4-n , graphite fine particles, a solvent and, if necessary, a dispersion of a colored pigment are mixed to form a colored film on the outer surface of the face of the cathode ray tube. Obtain a forming paint. In the paint for forming a colored film used herein, the mixing ratio of the colorant to the paint is expressed by the weight ratio with respect to the mixture of R ¹ nM (OR ² ) _{4-n with} a hydrolyzed condensation polymer, graphite fine particles or a colored pigment. (= Colorant / paint = (graphite fine particles or colored pigment) / (hydrolysis condensation polymer of R ¹ nM (OR ² ) _4-n + graphite fine particles or colored pigment))
It is preferable to set it to 60 to 60% by weight because the film strength, reliability, and high contrast performance can be exhibited in a well-balanced manner.

Excessive addition of graphite fine particles or graphite fine particles and a colored pigment in the paint for forming a colored film significantly lowers the total light transmittance of the film, thereby lowering the brightness of the cathode ray tube and lowering the film strength. If the graphite fine particles (or the graphite fine particles and the colored pigment) are too small, the film will not be sufficiently colored and the contrast of the cathode ray tube cannot be improved.

As a method of applying the paint for forming a colored film used here, a spin coating method, a spray method, a dipping method, or the like can be applied. When applied to a cathode ray tube, it is preferable to use a spin coating method in order to form a film having a uniform thickness on the front surface thereof.

The colored film thus obtained is kept at 350 ° C. or higher.
Since it has heat resistance within the temperature range of 00 ° C. or less, even if a colored film is formed on the panel before the cathode ray tube assembling process, a desired colored film can be obtained without fading in the heat treatment process. The colored film thus obtained is laminated in combination with a conductive film containing antimony-doped tin oxide, tin-doped indium oxide, gold, silver, palladium, etc., and / or a low refractive index film containing silicon oxide. It can also be used as a film.

As a method for forming the conductive film, a PVD method, C
A fine particle deposition method using a VD method, a thermal decomposition method, or a wet method can be applied. In particular, to form a film having a uniform thickness, CVD
It is preferable to use the method. As an example of the laminated film, a conductive film such as antimony-doped tin oxide or tin-doped indium oxide is formed as a first layer on the panel surface of a cathode ray tube, and a colored film composed of graphite fine particles and silicon oxide is laminated as a second layer. .

The structure of the laminated film is not limited to the above two-layer film. For example, as an example of a three-layer film, a film made of silicon oxide and titanium oxide is formed on a panel surface of a cathode ray tube as a first layer, and a conductive film such as antimony-doped tin oxide and tin-doped indium oxide is formed as a second layer. A third layer is formed by laminating a colored film composed of graphite fine particles and silicon oxide, and a first layer is formed by forming a colored film composed of silicon oxide, titanium oxide and graphite fine particles. A conductive film of tin, tin-doped indium oxide or the like is formed, and a film in which a film made of silicon oxide is stacked as a third layer, or a colored film made of silicon oxide, titanium oxide, and graphite fine particles is formed as a first layer, For example, a film in which a conductive film such as antimony-doped tin oxide or tin-doped indium oxide is formed as a second layer, and a film formed of graphite fine particles and silicon oxide is stacked as a third layer can be exemplified.

As an example of a four-layer film, a film made of silicon oxide is formed as the first layer on the panel surface of the cathode ray tube, a film made of silicon oxide and titanium oxide is formed as the second layer, and A conductive film such as antimony-doped tin oxide or tin-doped indium oxide is formed as a layer, a film formed by laminating a colored film composed of graphite fine particles and silicon oxide as a fourth layer, or a film composed of silicon oxide as a first layer. The second layer is formed with a colored film composed of silicon oxide, titanium oxide and graphite fine particles, the third layer is formed with a conductive film such as antimony-doped tin oxide and tin-doped indium oxide, and the fourth layer is formed with silicon oxide. A film made of silicon oxide, a film made of silicon oxide as a first layer, a colored film made of silicon oxide, titanium oxide and graphite fine particles as a second layer, and an antimony-doped oxide film as a third layer. tin, A film in which a conductive film such as doped indium oxide is formed and a film made of graphite fine particles and silicon oxide is stacked as the fourth layer can be exemplified, but it goes without saying that the structure of the stacked film is not limited to the above. .

In general, the antireflection ability of a laminated film is determined by the refractive index and thickness of the film and the number of laminated films. In consideration of the above, by appropriately designing the refractive index and the film thickness of the film, an effective antireflection effect can be obtained.

When a colored conductive laminated film including a conductive film is formed, an alkali barrier film containing silicon oxide is formed as a first layer on the panel surface of the cathode ray tube,
It is also possible to prevent deterioration of conductivity caused by an alkali component eluted from glass.

Further, if necessary, on the laminated film,
In order to impart non-glare properties, a silica film can be formed by a spray method. The colored film and the laminated film can be specifically applied to displays such as a cathode ray tube and a liquid crystal display panel.

[0036]

EXAMPLES Hereinafter, the present invention will be described specifically and in detail with reference to examples. It goes without saying that the present invention is not limited to the following examples. The characteristics of the colored film and the laminate obtained in each of the examples and comparative examples were measured as follows. (1) Haze and total light transmittance were measured using a haze meter (Model TC-H III DP) manufactured by Tokyo Denshoku Co., Ltd. (2) The surface resistance was measured using Loresta manufactured by Mitsubishi Chemical Corporation. (3) The reflectance was measured using a specular reflection jig having an incident angle of 5 ° with U-best 50 manufactured by JASCO Corporation. (4) Adhesion was measured according to MIL-C-675C, using a poppy rubber ER-30R manufactured by Lion Corporation with a load of 1 kgf, reciprocating 20 times while rubbing the surface, and causing damage to the film surface. The occurrence was visually observed and evaluated.

1. Paint for forming a colored film containing graphite fine particles A paint for forming a colored film containing graphite fine particles was prepared as follows. 30 g of graphite fine particles (particle size 0.02 μm), 10.5 g of polymer dispersant,
150 g of glass beads and 59.5 g of MEK (methyl ethyl ketone) were mixed and dispersed by a sand mill at 2500 rotations for 4 hours. Then, the glass beads were separated to obtain a uniform dispersion (a). 23.08 g of tetraethoxysilane and 18
6.03 g of ethyl alcohol, 1.06 g of 1N hydrochloric acid and 4.
Mix 81 g of pure water, ripen at 60 ° C for 1 hour,
A homogeneous solution (b) was obtained. 1.0 g of dispersion (a) and 7.7
8 g of the solution (b) and 91.22 g of ethyl alcohol were mixed to obtain a paint (A) for forming a colored film containing graphite fine particles.

2. High refractive index, conductive film forming paint 1.9 g of antimony-doped tin oxide fine powder (manufactured by Sumitomo Osaka Cement), 0.01 g of silicon-based surfactant and 98.09
g of water were mixed, and then dispersed for 10 minutes with an ultrasonic homogenizer to obtain a uniform dispersion (c).

3. Colored film [Example 1] One surface of a transparent glass substrate was adjusted to 40 ° C, and the coating (A) for forming a colored film containing the graphite fine particles was applied to this surface by a spin coating method. Dry with hot air for 30 seconds, and heat it at 450 ° C.
Heat treatment was performed for 30 minutes to form a colored film having a thickness of 0.1 μm. Table 1 shows the evaluation results in this case.

Example 2 The same operation as in Example 1 was performed. However, in addition to 25 g of graphite fine particles, Co-
Blue pigment which is an oxide compound of Al (particle size 0.03 μm)
5 g were added. Table 1 shows the evaluation results in this case.

Example 3 The same operation as in Example 1 was performed. However, in addition to 20 g of graphite fine particles, Co-
Black pigment which is an oxide compound of Fe-Cr (particle diameter 0.04
μm) 10 g. Table 1 shows the evaluation results in this case.

Example 4 The same operation as in Example 1 was performed. However, in addition to 15 g of graphite fine particles, Co-
Black pigment which is an oxide compound of Fe-Cr (particle diameter 0.04
μm) and 5 g of a blue pigment (particle diameter 0.03 μm) which is an oxide compound of Co—Al. Table 1 shows the evaluation results in this case.

Comparative Example 1 The same operation as in Example 1 was performed. However, a coating (B) for forming a colored film in which graphite fine particles were changed to carbon black was used. Table 1 shows the evaluation results in this case.

4. Laminate [Example 5] The transparent glass substrate was preheated after cleaning,
A thin film of tin oxide was formed on a glass surface by a CVD method. The surface of the glass substrate on which the tin oxide is formed is adjusted to a temperature of 40 ° C., and the coating (A) for forming a colored film containing the graphite fine particles is applied to the surface by spin coating.
Dry with warm air at a temperature of 50 ° C for 30 seconds,
A colored film having a thickness of 0.1 μm was formed by performing a heat treatment at 30 ° C. for 30 minutes to obtain a laminate of tin oxide and the colored film. Table 2 shows the evaluation results in this case.

Example 6 One surface of a transparent glass substrate was adjusted to a temperature of 40 ° C., and the dispersion (c) was applied to this surface by a spin coating method.
After drying for a second, a high-refractive-index conductive film having a thickness of 0.1 μm was formed. Next, the same operation as in Example 5 was performed to obtain a thickness of 0.1 μm.
Was formed. Table 2 shows the evaluation results in this case.

Example 7 The same operation as in Example 6 was performed. However, the antimony-doped tin oxide fine powder in the coating material for forming a high refractive index conductive film was changed to ITO powder. Table 2 shows the evaluation results in this case.

Example 8 The same operation as in Example 6 was performed. However, the fine powder of antimony-doped tin oxide in the coating material for forming a high refractive index conductive film was changed to silver powder. Table 2 shows the evaluation results in this case.

Comparative Example 2 The same operation as in Example 5 was performed. However, the coating (A) for forming a colored film was changed to the coating (B) for forming a colored film. Table 2 shows the evaluation results in this case.

[0049]

[Table 1]

[0050]

[Table 2]

[Effects] As shown in Tables 1 and 2, in the colored film of Comparative Example 1 and the laminate of Comparative Example 2, the transmittance before the heat treatment and the transmittance after the heat treatment change. On the other hand, in the colored films according to Examples 1 to 4 and the laminates according to Examples 5 to 8, it is shown that the transmittance before the heat treatment and the transmittance after the heat treatment hardly change, and the good transmittance is maintained. Have been. Therefore, in a display device manufactured by forming a film containing at least a colored film on the face glass surface and then performing heat treatment at a temperature of 350 to 500 ° C., by using graphite particles having high heat resistance as a coloring material, Even when a heat treatment step is required after the formation of the colored film, it is possible to form a practically usable colored film without impairing the high contrast effect and the color tone adjusting effect.

[0052]

As described above, according to the present invention, in the display device according to the first aspect, the colored film is formed by using the paint containing the graphite fine particles.
Even if heat treatment at ~ 500 ° C is performed, the colored film does not deteriorate and the transmittance does not change, it is possible to maintain a good transmittance before the heat treatment, and it is excellent in high contrast effect, color tone adjustment, etc. A display device can be easily realized.

Further, in the display device according to the second aspect, since the colored conductive laminated film includes a colored film formed by using a paint containing graphite fine particles, the temperature is 350 to 500 ° C. after the formation of the colored conductive laminated film. Even if heat treatment is performed, the color film does not deteriorate, the transmittance does not change, good transmittance before heat treatment can be maintained, high contrast effect, excellent color tone adjustment, etc., and antistatic In addition, a display device having an electromagnetic wave shielding effect can be easily realized.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Atsumi Wakabayashi 585 Tomimachi, Funabashi-shi, Chiba Sumitomo Osaka Cement Co., Ltd.

Claims (2)

[Claims] 1. A display device manufactured by forming a coating containing at least a colored film on the face glass surface and then performing a heat treatment at 350 to 500 ° C., wherein the colored film is formed by a paint containing graphite fine particles. A display device characterized by the above-mentioned. 2. The display device according to claim 1, wherein the coating containing the colored film is a colored conductive laminated film containing at least a conductive film.