JP3315673B2 - CRT with conductive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT with a conductive film having a conductive film on the surface of a CRT panel.

[0002]

2. Description of the Related Art A cathode ray tube operates at a high voltage, so that static electricity is induced on a surface of the cathode ray tube when the cathode ray tube is started or terminated. Dust adheres to the surface of the cathode ray tube due to the static electricity, causing a decrease in contrast or causing discomfort due to a slight electric shock when directly touched.

Conventionally, attempts have been made to provide an antistatic film on the surface of a CRT panel in order to prevent the above-mentioned phenomenon. For example, as described in JP-A-63-76247, the surface of a CRT panel is heated to about 350 ° C.
A method of providing a conductive oxide layer such as tin oxide and indium oxide by a VD method has been employed.

[0004] However, in this method, the cost of the apparatus is high, and the surface of the cathode-ray tube is heated to a high temperature, so that the phosphor in the cathode-ray tube is dropped off and the dimensional accuracy is reduced. In addition, tin oxide is most commonly used as a material for the conductive layer, but in this case, there is a disadvantage that it is difficult to obtain a high-performance film by low-temperature treatment.

[0005] In recent years, shielding of electromagnetic waves has also been required. By interposing the conductive coating on the surface of the cathode ray tube, electromagnetic waves hit the conductive coating, induce eddy currents in the coating, and reflect the electromagnetic waves by this action. However, for this purpose, good conductivity that can withstand high electric field strength is necessary, but it was more difficult to obtain a film with such good conductivity.

On the other hand, with respect to the production of a conductive film,
Although there is a method described in 10058, in this method, since a film is formed by applying a mixed solution of a metal salt and a reducing agent, the metal conductive film is in a state of being plated on a glass surface, and the strength of the film is extremely weak. In addition, there is a problem that a step of cleaning the conductive film and removing by-product salts is required.

As a method for forming an antistatic film on the entire panel of a cathode ray tube, Japanese Patent Application Laid-Open No. 63-160140 discloses a method of forming an antistatic film by adding a small amount of metal particles. Has a film surface resistance of the antistatic film to be formed of not less than 10 ⁷ Ω / □,
Although it exhibits an antistatic function, there is a problem that conductivity is insufficient to shield electromagnetic waves.

Further, the formation of the conductive film and the low-reflection film by the coating method has hitherto been realized not only for optical equipment but also for consumer equipment, especially televisions and cathode ray tubes (C) of computer terminals.
RT). Conventional film-forming methods include, for example, as described in JP-A-61-118931, a method of attaching a SiO ₂ layer having fine irregularities to the surface of a cathode-ray tube so as to have an antiglare effect, or using hydrofluoric acid to form a surface. Methods such as providing unevenness on the surface by etching have been adopted.

However, these methods are called non-glare treatments for scattering external light, and are not essentially methods of providing a low-reflection layer, so that there is a limit in reducing the reflectance. This also causes a reduction in resolution.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cathode ray tube having a high-performance conductive film and a cathode ray tube having a low-reflection conductive film which can be formed by low-temperature heat treatment and which overcomes the above-mentioned disadvantages of the prior art. It is in.

[0011]

According to the present invention, there is provided a conductive film containing a sol in which Ru metal fine particles are dispersed, and wherein at least 10 parts by weight of 100 parts by weight of the conductive film forming component are Ru metal fine particles. Provided is a cathode-ray tube with a conductive film having a conductive film formed from a coating solution for formation on the surface of the cathode-ray tube. The present invention also provides the above-described cathode-ray tube with a conductive film, wherein a film having a lower refractive index than the conductive film is formed on a conductive film formed from a coating solution for forming a conductive film.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The coating liquid for forming a conductive film according to the present invention is characterized in that it is prepared so as to contain at least 10 parts by weight of Ru metal fine particles per 100 parts by weight of a conductive film forming component.

The coating liquid for forming a conductive film according to the present invention contains fine metal particles in the form of a sol. When this is coated, unlike conventional plating films, minute holes are introduced into the conductive film. You. When a coating solution containing an alkoxide such as silicon, titanium, or zirconium and / or a partial hydrolyzate thereof is applied on the conductive film, the coating solution penetrates into the pores to reduce the strength of the conductive film. Significantly improved.

Unlike the conventional method using a coating solution composed of a metal salt and a reducing solution, the conductive film thus formed does not produce by-products when forming the conductive film, and has a low conductivity. There is no deterioration in film strength between the film and the film formed thereon.

As the metal fine particles used in the present invention, metal fine particles generated by evaporation and condensation of metal or metal fine particles generated by chemical reduction of a metal salt are preferable.

In the present invention, examples of the metal salt used for forming the metal fine particles include nitrates such as ruthenium nitroso nitrate, chlorides such as ruthenium chloride, ruthenium ammonium chloride, ruthenium potassium chloride and ruthenium sodium chloride, and ruthenium acetate. Acetate and the like can be used.

Examples of the metal salt reducing agent include hydrides such as sodium borohydride, potassium borohydride, sodium hydride, lithium hydride, formic acid, oxalic acid, phosphinic acid, sodium phosphinate, and Rochelle salt. Organic acids, inorganic acids, salts and the like can be used.

The fine metal particles are produced, for example, by dissolving the metal salt in water or an organic solvent, adjusting the pH with ammonia or the like as necessary, and then adding the reducing agent. At this time, it is also preferable to adjust the reaction temperature depending on the type of the liquid. The metal fine particles generated by such a method are appropriately washed and dried, and then solified by an operation such as stirring. At this time, in order to improve the dispersibility of the fine particles, the surface of the fine particles may be partially oxidized by heating, irradiation with ultraviolet rays, immersion in an oxidizing agent, or the like.

Since the Ru metal particles are difficult to disperse if they are too large, the average particle size is preferably 100 nm or less, more preferably 10 nm or more, and further preferably 30 to 50 nm. Powder volume resistance of metal fine particles is 0.01Ω
-Good results are obtained when the diameter is not more than cm.

It is important that the Ru metal fine particle powder is uniformly dispersed in water, an organic solvent or the like. When dispersing, it is preferable to perform stirring to facilitate contact between the solution and the powder. In this case, colloid mill, ball mill,
A commercially available pulverizer such as a sand mill or a homomixer can be used. Further, when dispersing the fine particles, 20 to 200
Heating in the range of ° C. is also possible. When stirring at a temperature higher than the boiling point of the dispersion medium, pressurization is performed so that the liquid phase can be maintained. In this way, an aqueous sol or organosol in which Ru metal fine particles are dispersed as colloid particles is obtained.

The above-mentioned aqueous sol can be used as a coating solution as it is, but it is also possible to disperse the fine metal particles in an organic solvent or to replace the water in the aqueous sol with a hydrophilic organic solvent in order to increase the coating property on the substrate. . As the hydrophilic organic solvent, alcohols such as methanol, ethanol, propanol and butanol, ethyl cellosolve, methyl cellosolve, butyl cellosolve, ethers such as propylene glycol methyl ether, ketones such as 2,4-pentadione and diacetone alcohol, Esters such as ethyl lactate and methyl lactate can be used.

The above-mentioned coating liquid in the present invention has M (OR) from the viewpoint of adjusting the viscosity, surface tension and spreadability of the liquid.
_y · R ′ _4-y (y is 2, 3 or 4, M is Si, Ti or Zr, R is an alkyl group, R ′ is an alkyl group or an acetylacetonate group) metal alkoxide and / or a partial hydrolyzate thereof Decomposition products can also be added.

For the purpose of adjusting the thickness of the conductive film, for example, oxide fine particles of at least one metal selected from the group consisting of Sn, Sb, In, Zn, Ga, Au and Ru are added to the coating solution. It may be contained in the form of a sol similar to the metal fine particles. The size of such oxide fine particles is 10
0 nm or less, especially the range of 10-50 nm is preferable. As described above, the amount of the oxide fine particles added to the metal fine particles is 0 to 100 per 100 parts by weight of the metal fine particles.
A proportion by weight is preferred. Further, various surfactants can be added to the coating solution in order to improve the wettability with the substrate at the time of coating.

In the coating solution of the present invention, it is necessary that the metal fine particles are the main component among the conductive film forming components contained in the coating solution, and the film forming component in the coating solution is 100% by weight. (In this case, the oxide raw material is calculated in terms of oxide and the metal raw material is calculated in terms of metal), the metal fine particles are contained in an amount of 10 parts by weight or more. If the amount of the metal fine particles is less than 10 parts by weight, it is difficult to obtain desired conductivity in the formed conductive film. The content ratio of the metal fine particles is preferably at least 50 parts by weight, more preferably at least 80 parts by weight.

As a method of applying the coating solution on the substrate in the present invention, for example, spin coating, dip coating,
A method such as spray coating can be suitably used. Also,
Irregularity may be imparted by forming irregularities on the surface by using a spray coating method, and a hard coat such as a silica coating may be provided thereon. Furthermore, the conductive film according to the present invention is formed by spin coating or spray coating,
A solution containing silicon alkoxide may be spray-coated thereon to provide a non-glare coat of a silica coating having irregularities on the surface.

When a low-boiling solvent is added to the coating solution of the present invention, a coating film can be obtained by drying at room temperature.
When a medium to high boiling point solvent having a temperature of from 00 to 250 ° C. is used, the coating film is subjected to a heat treatment because the solvent remains in the coating film at room temperature. The upper limit of the heating temperature is determined by the softening point of the substrate. Considering this point, a preferable heating temperature range is 100 to 500 ° C.

In the present invention, a low reflection film utilizing the interference effect of light can be formed on the conductive film surface. For example, when the substrate is glass (refractive index n = 1.52), the ratio of (refractive index of conductive film) / (refractive index of low refractive index film) is about 1 on the conductive film. .23, the reflectance of the conductive film can be reduced most. In order to reduce the reflectance, it is preferable to reduce the reflectance in the visible light region, particularly at 555 nm. However, in practice, it is preferable to determine the reflectance appropriately in consideration of the reflection appearance and the like.

The outermost of such a two-layer low-reflection conductive film
As the low refractive index film of the layer, MgF_TwoSolutions and sieves containing sols
One selected from solutions containing recon alkoxides
It can be formed using a solution composed of the above. Consider the refractive index
Considering that MgF _TwoIs the lowest and the reflectance is reduced
For MgF_TwoIt is preferable to use a solution containing a sol.
In terms of film hardness and scratch resistance, SiO_TwoWith the main component
Is preferred.

Various solutions can be used as the solution containing the silicon alkoxide for forming the refractive index film.
A liquid containing a silicon alkoxide represented by (OR) _y · R ′ _4-y (y is 3 or 4, R is an alkyl group, and R ′ is an alkyl group) or a partial hydrolyzate thereof is exemplified. For example, a monomer or polymer of silicon ethoxide, silicon methoxide, silicon isopropoxide, or silicon butoxide can be preferably used.

The silicon alkoxide can be used by dissolving it in an alcohol, an ester, an ether, or the like, and adding an aqueous solution of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, formic acid, maleic acid, hydrofluoric acid, or ammonia to the above solution. Silicon alkoxide can be used after hydrolysis.
Further, the silicon alkoxide is used in an amount of 30 to the solvent.
It is preferably contained in an amount of not more than weight%. If the solid content of the silicon alkoxide is too large, the storage stability of the obtained coating solution is poor, and thus such a solid content is preferable.

An alkoxide such as Zr, Ti, Sn or Al or a partial hydrolyzate thereof is added to the solution as a binder for improving the strength of the film.
Any one or two or more composites selected from O ₂ , TiO ₂ , SnO _2, and Al ₂ O ₃ are formed by using MgF ₂ or SiO ₂
At the same time, they may be precipitated.

A surfactant may be added to increase the wettability with the substrate. Examples of the surfactant to be added include sodium linear alkylbenzene sulfonate and alkyl ether sulfate.

The method for producing a low-reflection conductive film according to the present invention can be applied to a low-reflection conductive film by a multilayer interference effect.
As a configuration of a multilayer low reflection film having antireflection performance,
Assuming that the wavelength of the light to be antireflective is λ, the low refractive index layer having a high refractive index layer and a low refractive index layer having an optical thickness of λ / 2 to λ / 4 or λ / 4 to λ / 4 is formed from the substrate side. From the reflective film and the substrate side, the medium refractive index layer-high refractive index layer-low refractive index layer
4 to λ / 2 to λ / 4, a low-reflection film of three layers, and a low-refractive-index layer, a middle-refractive-index layer, a high-refractive-index layer, and a low-refractive-index layer from the substrate side to an optical thickness of λ / 2 to λ / A typical example is a four-layer low-reflection film formed at 2 to λ / 2 to λ / 4. The film formed from the coating solution in the present invention can be used for the above-mentioned medium refractive index layer or high refractive index layer.

Further, the film formed from the coating solution in the present invention absorbs over the entire visible light range.
It also contributes to the improvement of contrast.

As the substrate on which the conductive film and the low-reflection conductive film of the present invention are formed, there is a cathode ray tube panel.

The thickness of the conductive film thus obtained in the present invention can be arbitrarily adjusted.
~ 0.1 μm, preferably about 0.02-0.05
It is in the range of μm. If the film thickness is too small, the fine particles are present in an island shape, the conductivity chain is insufficient, and it is insufficient in that the desired conductivity cannot be obtained. Absorption is too strong, and the transmittance of light in the visible light region is too low.

In a preferred embodiment of the present invention, a low refractive index film is formed on the surface of the conductive film, but the thickness of the low refractive index film can be arbitrarily adjusted. Suitable thicknesses for the purposes of the present invention are from about 0.03 to 1 μm, preferably from about 0.03 to 0.3 μm.
It is in the range of 08 μm. When the thickness is out of the above range, the low reflectivity due to the double interference effect is not sufficiently realized.

[0038]

The present invention will be further described below with reference to examples of the present invention, but the present invention is not limited to these examples. In the following Examples (Examples 1 to 3) and Comparative Examples (Example 4), the evaluation methods of the obtained films are as follows. Table 1 shows the evaluation results.

1) Conductivity evaluation: Surface resistance value (unit: Ω) of the film surface measured by a Loresta resistance meter (Mitsubishi Chemical Corporation)
/ □) was measured. In the table, 7.2E2 is 7.2 × 1
0 ² , and so on. 2) Scratch resistance: The membrane surface was reciprocated 50 times with an eraser (50-50, manufactured by Lion Corporation) under a load of 1 kg, and the surface was visually judged for scratches. The evaluation criteria were as follows: ○: no scratch at all, Δ: slightly scratched, ×: partial peeling of film,
And 3) Pencil hardness: Under a load of 1 kg, the film surface was scanned with a pencil, and thereafter the pencil hardness at which surface scratches began to be visually determined was determined as the pencil hardness of the film. 4) Luminous reflectance: The luminous reflectance of the multilayer film at 400 to 700 nm was measured using a GAMMA spectral reflectance spectrum measuring instrument. 5) Luminous transmittance: Luminous transmittance at 380 to 780 nm was measured with a spectrophotometer U-3500 manufactured by Hitachi, Ltd.

The powder volume resistance of the obtained metal fine particles was measured by a four-terminal method, and the average particle size of the obtained sol was measured by a laser diffraction particle size analyzer LPA-3100 manufactured by Otsuka Electronics.

Example 1 A sodium borohydride solution was added to a ruthenium trichloride aqueous solution (solid content: 10% by weight) in an amount of 4 times mol of ruthenium to reduce and precipitate metal ruthenium. After thoroughly washing this metal ruthenium, 1
Drying was performed at 00 ° C. for 24 hours to obtain a metal ruthenium powder. This metal ruthenium powder was ground with a sand mill for 20 minutes. At this time, the average particle size of the particles in the liquid was 89 nm. Thereafter, concentration was performed to obtain a 5% by weight solid solution (A
liquid).

Ethyl silicate is dissolved in ethanol and hydrolyzed with an aqueous hydrochloric acid solution to give 5% by weight in terms of SiO _2.
An ethanol solution was prepared (solution B). Solution A and solution B were mixed so that solution A / solution B = 8/2 (weight ratio), and then ultrasonic waves were applied for 1 hour (solution C).

Water, ethanol, methanol and propylene glycol monomethyl ether were mixed at a weight ratio of water / ethanol / methanol / propylene glycol monomethyl ether = 50/42/5/3 (D
liquid). The liquid C was diluted with the liquid D so as to have a solid content of 1.0% by weight to obtain a coating liquid (liquid E). Solution E was applied to the surface of a type 14 cathode ray tube by spin coating, and heated at 180 ° C. for 30 minutes to form a conductive film.

Example 2 Isopropanol, propylene glycol monomethyl ether acetate and diacetone alcohol were mixed so that the weight ratio of isopropanol / propylene glycol monomethyl ether acetate / diacetone alcohol was 6/3/1 (T1 solution).

The solution A prepared in Example 1 was used as the solution D and had a solid content of 0.
The solution was diluted to 8% by weight, applied to the surface of a type 14 cathode ray tube by spin coating, and dried at 60 ° C. for 10 minutes.
Thereafter, a solution obtained by diluting the solution B to 0.85% by weight with the T1 solution was applied on the film by a spin coating method.
After baking for a minute, a low reflection conductive film was obtained.

Example 3 Indium oxide particles in which 9% by weight of tin was substituted and solid-dissolved were pulverized and pulverized by a sand mill for 1 hour. Ru / In ₂ O ₃ = 9/1 with ruthenium chloride
(Weight ratio), and sodium borohydride was further added to this solution in an amount of 8 times the amount of ruthenium, to thereby reduce and precipitate ruthenium. Further, an anion exchange resin and a cation exchange resin were sequentially added to this liquid to remove impurity ions, and the mixture was dispersed by irradiation with ultrasonic waves for 2 hours.
Thereafter, concentration was performed to prepare a 5% by weight solid solution (V1
liquid).

The solution V1 was diluted with the solution D so that the solid content was 0.9% by weight, applied to the surface of a type 14 cathode ray tube by a spin coating method, and dried at 60 ° C. for 10 minutes. Thereafter, a solution obtained by diluting Solution B to 0.85% by weight with T1 solution was applied on this film by spin coating, and baked at 160 ° C. for 30 minutes to obtain a low reflection conductive film.

Example 4 Indium oxide particles in which 5% by weight of tin was substituted and solid-dissolved were pulverized with a sand mill for 1 hour to peptize. Ag / In ₂ O ₃ = 5/95
(Weight ratio), and ammonia was added to the solution to adjust the pH to 11. next,
To this solution was added Rochelle's salt in an amount 8 moles per mole of silver, and 1
After stirring for an hour, silver was precipitated by reduction. The solution was further added with an anion exchange resin to remove NO ₃ ^- ions, and dispersed by irradiating ultrasonic waves for 2 hours. Thereafter, the mixture was concentrated to prepare a solution having a solid content of 5% by weight (solution X1). Solution V1 in Example 3 was replaced with X
The same procedure as in Example 3 was carried out except that one liquid was used.

[0049]

[Table 1]

[0050]

According to the present invention, an excellent conductive film can be efficiently provided by a simple method such as spraying or spin coating. Since the present invention provides a conductive film made of metal fine particles, it can easily shield electromagnetic waves and can be manufactured relatively inexpensively. In particular, it can be sufficiently applied to a large-area substrate such as a panel face surface of a CRT and can be mass-produced, so that its industrial value is very high.

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Go Morimoto 1150 Hazawacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Asahi Glass Co., Ltd. Examiner at Central Research Laboratory Shuhei Horibe (56) References JP10-1777 (JP, A) JP-A-9-115438 (JP, A) JP-A-5-190091 (JP, A) JP-A-63-160140 (JP, A) JP-A-4-155732 (JP, A) JP-A-9-55175 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 29/88 H01J 29/89

Claims (2)

(57) [Claims] A sol containing Ru metal fine particles dispersed therein and at least 10 parts by weight of R in 100 parts by weight of a conductive film forming component.
A CRT with a conductive film having a conductive film formed from a coating solution for forming a conductive film prepared to be u-metal fine particles. 2. The CRT with a conductive film according to claim 1, wherein a film having a lower refractive index than the conductive film is formed on the conductive film formed from the coating liquid for forming a conductive film.