KR19990079515A - Electro-reflective film composition of shadow mask for color cathode ray tube - Google Patents

Abstract

The present invention relates to an electron reflection film composition of a shadow mask for color cathode ray tubes, and more particularly, to maintain a high level of film bonding force between the shadow mask and the coating layer, thereby suppressing the doming phenomenon during operation of the cathode ray tube, thereby providing a high quality image. have.

In order to achieve the above object, the present invention provides a shadow mask for a color cathode ray tube which coats an electron reflection film on an electron beam irradiated surface of the shadow mask in order to suppress the doming phenomenon of the shadow mask.

Suspension for coating the electron reflection film is pure and, e as a reflection of tungsten (WO _3), a dispersant oxidation as a material SO ₃ Na ^- containing at least one of the ^{_{-, PO 3 -, COOH -}} , OH -, SO 3 Prepared by adding anionic surfactant, polyvinyl alchol to improve adhesion after coating, and silica-sol as a binder.

Description

Electro-reflective film composition of shadow mask for color cathode ray tube

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask for color cathode ray tubes, and more particularly, to an electron reflection film composition of a shadow mask for forming an electron reflection film made of a material having a high electron beam reflectance on the electron beam irradiated surface side of the shadow mask to reduce the amount of shadowing of the shadow mask. It is about.

As shown in FIG. 1, a general color cathode ray tube includes a panel 2 having a dot or stripe type fluorescent film 1 that emits red, green, and blue light, respectively, on its inner surface. And a funnel 3 fused to the rear end of the panel 2 to maintain the inside of the cathode ray tube in a vacuum state, an electron gun 5 enclosed in the neck portion 4 of the funnel 3, and the electron gun ( A deflection yoke 7 for deflecting the electron beam 6 to the entire area of the screen so that the electron beam 6 emitted from 5 can strike the entire surface of the fluorescent film 1, and a plurality of slots or dots (dot) openings are arranged so that the shadow mask 8 serves as the color discriminating function of the electron beam 6, and the frame 9 supporting the shadow mask 8 so as to be maintained at a predetermined distance from the panel 2. And an inner shield 10 supported by the frame 9 to shield the geomagnetic field.

When power is applied to the color cathode ray tube constructed as described above, the electron beam 6 is emitted from the electron gun 5 inserted into the neck portion 4, and about 20% of the electron beam 6 breaks the opening of the shadow mask 8. By hitting the fluorescent film 1, the image is reproduced.

Meanwhile, the remaining 80% of the electron beam 6 collides with the shadow mask 8 to cause a temperature increase. As a result, the shadow mask 8 undergoes thermal expansion, thereby causing a domming phenomenon in which the surface thereof swells.

As a result, the mislanding amount of the electron beam 6 is increased, thereby degrading the color purity.

In order to solve this problem, various methods of forming a coating layer on the electron beam irradiated surface of the shadow mask 8 have been proposed. For example, in US Patent 3,562,518, a thickness of 20 mg / t on the electron beam irradiated surface of the shadow mask 8 is proposed. It has been proposed to form an electron reflection film from bismuth oxide (Bi ₂ O ₃ ) and glass at ₂ cm ₂ , and in Japanese Laid-Open Patent Publication 55-76553, an electron reflection layer containing W, Pb, and Bi is applied to an electron reflection layer. It is proposed to form, "Korean Patent No. 85-1589" is applied to the bismuth oxide (Bi ₂ O ₃ ) particles of 1㎛ or less with water glass at 1mg / ㎠ and 0.2mg / in the hole of the shadow mask (8) It has been proposed to apply in cm 2.

However, the following problems occurred in these examples.

First, US Patent 3,562,518 has an electron reflection effect, but when applied by spraying more than 5mg / cm 2, mask hole clogging tends to occur, making it difficult to use realistically, and Japanese Patent Laid-Open No. 55-76553 contains W, Pb, and Bi. Applying about 10㎛ to the electron reflecting layer has an electron reflecting effect, but when applied to 2 ~ 3㎛ or more, the electron reflecting effect is the same, when applying more than 4㎛ can be said to be less practical because the shadow mask hole clogging occurs. In addition, when applying tungsten (W), a method of depositing tungsten (W) or applying tungsten oxide (WO ₃ ) is used, and when depositing tungsten (W), a frit sealing process of 450 ° C. and exhaust while when the respective heat-treated to less than 3 hours in the process of tungsten (W) is becomes liable to occur the peeling is oxidized to tungsten oxide (WO ₃₎ film, the adsorbed water in the tungsten oxide (WO ₃₎ surface evaporation the binding force between the water-glass It became weak and the strength of the film after drying became very weak, and the problem of peeling the film even after heat treatment occurred.

In Korean Patent Publication 85-1589, when the electron reflection film is formed using fine particles of bismuth oxide (Bi ₂ O ₃ ) of 1 μm or less, when the coating is performed within 1 μm, the electron reflecting effect is not so large that only about 20% of the dope effect appears. It became.

On the other hand, the method of forming the electron reflection film is typically added to the electron reflecting material, a binder (Binder), an appropriate amount of pure water, a dispersant and then dispersed by using a disperser to form a suspension and then sprayed on the shadow mask (8) It is applied by the method of the present invention, and naturally dried, and then put into a manufacturing process of a conventional color cathode ray tube which is heat-treated in a furnace at 450 ° C.

In this case, tungsten oxide (WO ₃ ) is used as an electron reflecting material for preventing the dominant phenomenon of the shadow mask 8, and is composed of a material containing carry silicate or sodium silicate as a binder, the content of carry silicate or sodium silicate Increasing the amount of inorganic powder precipitates and dispersibility decreases, and the amount of gas released from the coating (eg, H ₂ O, CO, and CO ₂ ) by heating and electron irradiation increases. The cathode is severely polluted, which reduces the lifespan of the cathode and shortens the life of the cathode ray tube. In addition, due to peeling of the film, a quality problem such as a discharge failure due to clogging of the shadow mask during spraying or dropping of the film during the manufacturing process occurs.

Accordingly, there is a need for the production of an electron reflection film having excellent adhesion and electron reflection characteristics of a film without generating gas and discharging.

The present invention has been devised in view of this point, and in constructing a suspension for coating a shadow mask, tungsten oxide (WO ₃ ) as an electron reflection material, silica sol as a binder, and an anion as a dispersant (eg, ^{_{SO 3 Na -, PO 3 -}} , COOH -, OH -, SO 3 - , etc.) dispersion and coating by forming by the addition of polyvinyl alcohol (polyvinyl Alchol) for maintaining an anionic surface active agent and, upon drying adhesive containing After the adhesiveness is good to prevent mask clogging and film falling off, through this purpose to enhance the emission life characteristics of the cathode.

1 is a block diagram of a general color cathode ray tube.

2 is a comparative view of the dominant amount of a color cathode ray tube according to the present invention and a conventional product.

*** Explanation of symbols for the main parts of the drawing ***

1: fluorescent film 2: panel

3: funnel 4: neck part

5 electron gun 6 electron beam

7: deflection yoke 8: shadow mask

9: frame 10: inner shield

Hereinafter, described in detail with reference to the accompanying drawings of the present invention.

In general, the coating layer of the shadow mask for color cathode ray tubes includes an electron reflecting material, a binder, and an appropriate amount of pure water and a dispersant. The coating material of the shadow mask according to the present invention comprises tungsten oxide (WO ₃ ) as an electron reflecting material and a binder silica sol (Slica-sol) and the anion as a dispersion agent (such as ^{_{SO 3 Na -, PO 3 -}} , COOH -, OH - -, SO 3 , etc.), anionic surfactants containing, In addition keep the drying adhesive It was configured by adding polyvinyl alcohol (Polyvinyl Alchol) to.

In more detail, in order to prevent the doming phenomenon due to thermal expansion of the shadow mask, in order to enhance the dispersion and adhesion, which are problematic in forming an electron reflection film using tungsten oxide (WO ₃ ) as an electron reflection material, anion ( ^{_{example: SO 3 Na -, PO 3}} -, COOH -, OH -, SO 3 - , etc.) helps promote dispersion in combination with the water molecules of the tungsten oxide surface, in order to uniformly spray during electron reflection film SO ₃ Na ^{_{-, PO 3 -, COOH -}} , OH -, sO 3 - , at least were one to more than enhance the dispersibility by the addition of an anionic surface active agent containing a polyvinyl alcohol during the drying by the addition of (polyvinyl Alchol) film adhesion of the St. The silica-sol was added to increase the adhesion of the film due to the fusion of the silica-sol even after the heat treatment.

Here, in the preparation of the spray liquid, the tungsten oxide is used having a particle size of 0.1 ~ 3㎛, the silica-sol using a particle diameter of 100nm or less, the thickness of the electron reflection film is 0.5 ~ 5㎛ At this time, the composition ratio of tungsten oxide: anionic surfactant: polyvinyl alcohol: silica-sol is about 100: 0.3 to 10: 1 to 10: 5 to 35.

The basis of this configuration is as follows.

First, when the particle size of the tungsten oxide is configured to about 0.1 to 3 μm, dispersibility decreases when the size is 0.1 μm or less, and a problem of mask clogging during spraying occurs at 3 μm or more.

In addition, when adding an anionic surfactant used as a dispersant in the amount of 0.3 to 10% of the content of tungsten oxide, when the content is less than 0.3%, the dispersing effect is less, and when more than 10% is added, Since the same effect is achieved, the meaning of excessive addition disappears.

When 1 to 10% of polyvinyl alcohol is added at 1% to 10% of the content of tungsten oxide to maintain adhesion when drying, film drop occurs at 1% or less, and at 10% or more, burning and peeling occurs during heat treatment. .

When the silica-sol used as a binder is added in an amount of 5 to 35% compared to the content of tungsten oxide, there is a problem of adhesiveness when the content is 5% or less, and a problem of nozzle clogging due to an increase in the spray liquid viscosity at 35% or more do.

In forming the film thickness at the time of spraying at 0.5-5 micrometers, when the thickness is 0.5 micrometer or less, the dope reduction effect by an electron reflection film becomes ineffective, and the mask clogging problem arises at 5 micrometers or more.

Under the above conditions, the mixture is mixed so that the viscosity is about 3 to 6 cps, and the spray liquid is formed. The pressure is adjusted to a spray amount of 6 to 9 l / min, sprayed on the electron beam irradiation surface of the mask, dried at room temperature, and then 400 to 450 ° C. Heat treatment for less than 3 hours to form an electron reflection film.

Based on this, the following results were evaluated.

Example 1

100 g of tungsten oxide is added to 500 g of pure water as an electron reflecting material for reducing dope, and then dissolved at room temperature.

Next, 0.5 g of an anionic surfactant containing SO ₃ Na ^- was added for the purpose of preventing agglomeration between particles, and then ball milling for about 3 hours, and a silica-sol having a concentration of 20% as a binder was added thereto. 100 g and 2 g of polyvinyl alcohol are added, followed by ball milling, and then sprayed onto the electron beam irradiated surface of the shadow mask with the spray liquid thus formed and applied to a thickness of about 1 μm.

The shadow mask thus obtained was introduced into a conventional color cathode ray tube manufacturing process to produce a 29 "color cathode ray tube, and the dominant properties and adhesion were evaluated.

In evaluating the dominant characteristics, the dominant characteristics due to thermal expansion of the shadow mask were evaluated for 1 hour while operating for 3 hours from the end point of the horizontal reference line of the screen to the center direction. When the cellophane tape of 2 cm and 3 cm in length was attached and removed, the tape was evaluated to the extent that the electron reflection film appeared on the tape.

As a result, the domming property was reduced by 20% when the fertilizer and the color cathode ray tube without electron reflecting film were fertilized, and the adhesion of the membrane was very good, and the emission life of the cathode due to the gas generated inside the cathode ray tube was very good. The results of the test also showed good results.

Example 2

100 g of tungsten oxide is added to 500 g of pure water, and it is dissolved at room temperature. 20 g of silica-sol as a binder and 3 g of a surfactant as shown in Formula 1 were added thereto, followed by ball milling for about 3 hours, 2 g of polyvinyl alcohol, followed by ball milling. After spraying on the electron beam irradiated surface of the shadow mask and applying the thickness of about 2㎛, the method of Example 1 showed that 25% of the dominant reduction effect and adhesive strength were found to be good. The results of the discharge life test of the cathode due to the internally generated gas also showed good results.

FIG. 2 is a graph comparing the dominant amount of the coating layer formed on the shadow mask in the general color cathode ray tube (Examples 1 and 2) and the one not based on the above-described basis, the difference being about 20 μm I can see that.

As described above, in the present invention, when the electron reflection film is coated on the electron beam irradiated surface of the shadow mask, the suspension is mixed with a predetermined amount of pure water, tungsten oxide, anionic surfactant, polyvinyl alcohol, and silica-sol at a constant ratio. By constitution, the adhesion after drying is improved, as well as the dispersibility and discharge life characteristics of the cathode are improved, and there is an effect of solving the voids and stray defects of the nozzles used for the shadow mask and the spray.

Claims (5)

In the shadow mask for color cathode ray tubes, in which an electron reflecting film is coated on the electron beam irradiation surface of the shadow mask in order to suppress the ming phenomenon of the shadow mask, The suspension for coating the electron reflection film is pure water, Tungsten oxide (WO ₃ ) and an electron reflecting material, An anionic surfactant containing at least one of SO ₃ Na ⁻ , PO ₃ ⁻ , COOH ⁻ , OH ⁻ , and SO ₃ ^- as a dispersant, Polyvinyl alcohol (Polyvinyl Alchol) to improve adhesion after coating, An electron reflection film composition of a shadow mask for color cathode ray tubes, characterized by adding silica-sol as a binder. The method of claim 1, The composition of said tungsten oxide: anionic surfactant: polyvinyl alcohol: silica-sol is 100: 0.3-10: 1-10: 5-35, The electron reflection film composition of the shadow mask for color cathode ray tubes. The method of claim 1, The tungsten oxide is electron reflection film composition of the shadow mask for color cathode ray tube, characterized in that the particle size of 0.1 to 3㎛. The method of claim 1, The silica-sol is an electron reflection film composition of the shadow mask for color cathode ray tube, characterized in that the particle diameter is 100nm or less. The method of claim 1, The electron reflection film composition of the shadow mask for color cathode ray tube, characterized in that the thickness of the electron reflection film is formed from 0.5 to 5㎛.