KR930009265B1 - Colour braun tube for phosphor - Google Patents

Abstract

This is a new fluorescent material for color CRT which is surface treated in order to enhance retrogradation protection and luminescence. The fluorescent material is composed of fluorescent pigments, ethylsilicate and a hydrolysis agent. Pref. the hydrolysis agent is urea and using amount is 0.1-10wt.%. The manufacturing method comprises (A) mixing fluorescent pigment in purified water; (B) dissolving ethylsilicate in ethanol and adding in (A); (C) adding urea and heating smoothly at 30-90≰C for 1-24 hour; (D) adding 0.1-0.5 wt.% of 10% aluminum nitrate and 10% zinc sulfate; and E) adding a little NH4OH and making pH 6-12.

Description

Phosphor for Color Cathode Ray Tubes

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to phosphors for color cathode ray tubes, and more particularly, to phosphors for color cathode ray tubes surface-treated to improve aging prevention and luminous luminance of red, green and blue phosphors used in color cathode ray tubes.

In general, a fluorescent film for color cathode ray tubes is regularly arranged in the form of phosphor dots or stripes in which the inner surface of the glass panel emits red, green, and blue colors, and a film of light absorbing material such as graphite is deposited on the phosphor array gaps. Has The fluorescent film having such a structure is usually formed by a photolithography method.

As described above, the fluorescent film formed by the photolithography method has poor color uniformity due to mixing between the phosphors, adhesion to the phosphors and the panel, and poor uniformity of particles. Degrades.

In order to overcome this problem, there is a need for improvement of the composition of the phosphor slurry, the production method, or the surface treatment of the phosphor used in the phosphor slurry.

Therefore, one of the methods of obtaining an excellent fluorescent film by treating the surface of the phosphor is to attach phosphates such as silicon dioxide, magnesium, zinc, calcium, and aluminum to the surface of the phosphor to uniformly disperse the phosphor particles in the phosphor slurry, thereby providing excellent dispersibility. It is to obtain a fluorescent film having excellent smoothness and luminance.

Potassium silicate (K ₂ O · nSiO ₂ ), Na ₄ P ₂ O ₇ · 10H ₂ O, A1 (NO ₃ ) ₃ · 9H ₂ O, ZnSO ₄ · 7H to form Si compound on the surface of phosphor during phosphor surface treatment ₂ O and NH ₄ OH were mixed and used. Recently, however, in order to further improve the properties of the fluorescent film (eg, adhesion, stripe width, packing density, etc.), ethyl silicate is often used instead of potassium silicate.

When ethyl silicate is used, hydrolysis of the ethyl silicate results in precipitation of silicon dioxide, which uses alkalis such as ammonia water and sodium hydroxide during hydrolysis. However, when alkali is used, the reaction proceeds radically at the same time as alkali addition, and the size of SiO ₂ precipitate is irregular, so that the particles are not evenly and densely formed.

Therefore, the surface-treated phosphor has a problem in that the adhesion and packing density of the panel are lowered, resulting in aging and poor dispersibility, so that the formed phosphor film is not smooth and the luminous luminance is also lowered.

Disclosure of Invention It is an object of the present invention to provide a surface-treated phosphor which improves adhesion and packing density to a panel in view of the above problems to form a phosphor film having excellent smoothness and luminous luminance.

In order to achieve the above object, the phosphor of the present invention is characterized in that, in the phosphor for color cathode ray tube composed of phosphor for color cathode ray tube, ethyl silicate attached to the phosphor, and a hydrolytic agent, the hydrolyzating agent is an element.

The amount of the element used in the present invention is 0.01 to 20% by weight, preferably 0.1 to 10% by weight based on 100% by weight of the phosphor for color cathode ray tube.

Alcohols used in the present invention include methanol, ethanol, isopropyl alcohol, butanol, and the like, and zinc salts include ZnSO ₄ , Zn (NO ₃ ) ₂ , and aluminum salts such as A1 (NO ₃ ) ₃ and A1 _2. (SO ₄ ) ₃ and the like, and urea was used instead of ammonia water.

In addition, the phosphor used in the present invention includes a zinc sulfide-based phosphor having ZnS as a parent, for example, ZnS: Cu, A1, Zns: Au, Cu, A1, ZnS: Ag, Ans: Ag, A1, ZnS : Zn, ZnS: Au, ZnS: Ag, C1 and the like.

Phosphors for color cathode ray tubes used in the present invention include those which are red, green and blue light emitting phosphors that can be used in the fluorescent film.

Hereinafter, the manufacturing method of the phosphor of the present invention will be described.

First, add phosphor to pure water and mix well.

Ethyl silicate is then dissolved in ethanol and added to the mixture. After urea was added, the mixture was slowly warmed at 30 to 90 ° C. for 1 to 24 hours, and then 10% aluminum nitrate solution and 10% zinc sulfate solution were added at 0.1 to 0.5% by weight (based on 100% by weight of phosphor), respectively. The phosphor of the present invention was prepared by adjusting the pH to 6-12 by adding a small amount of NH ₄ OH.

Referring to the preferred embodiment of the present invention.

Example 1

에 ZnS : Ag, C1 형광체 1 kg을 넣어 충분히 혼합한다. 에틸실리케이트 10 g을 에탄올 50 ml에 용해하여 이 혼합물에 첨가한후 교반하면서 요소 20 g을 가하고 50℃에서 2시간 동안 서서히 중탕가온한다. 이 용액에 10% A1(NO₃)₃용액 100 ml, 10% ZnSO₄용액 100 ml를 각각 첨가하고 NH₄OH를 가하여 pH를 8로 조정하였다.Pure 2

Put 1 kg of ZnS: Ag, C1 phosphor and mix well. 10 g of ethyl silicate is dissolved in 50 ml of ethanol, added to the mixture, and 20 g of urea is added with stirring, and the mixture is slowly warmed at 50 ° C. for 2 hours. To this solution was added 100 ml of 10% A1 (NO ₃ ) ₃ solution and 100 ml of 10% ZnSO ₄ solution, respectively, and the pH was adjusted to 8 by adding NH ₄ OH.

After leaving the solution for 1 hour to precipitate the surface-treated phosphor, the supernatant was removed by tilting, washed five times with pure water, dehydrated, and dried at 150 ° C. for 5 hours to obtain the surface-treated phosphor of the present invention.

Example 2

The surface treatment phosphor of the present invention was obtained in the same manner as in Example 1 except that 20 g of ethyl silicate and 40 g of urea were used.

The surface-treated phosphor of the present invention thus obtained has ammonia groups with hydrolysis of urea as compared with the phosphors obtained by hydrolyzing ethyl silicate using alkalis such as aqueous ammonia and sodium hydroxide. As the pH is moved to the alkali side, the silicate is hydrolyzed at this time, and thus very fine, uniform and dense SiO ₂ particles are produced.

Therefore, since the adhesion is evenly and small on the surface of the phosphor, the dispersibility is improved. In addition, there was almost no phosphor aggregation, and the particle distribution was very excellent, and the film filling density was excellent when forming the fluorescent film, and thus the emission luminance was improved by about 5 to 10%.

As described above, according to the present invention, when hydrolyzing the ethyl silicate used for the surface treatment of phosphor, urea was used instead of ammonia. When the particle is uniform, the dispersibility is excellent and the filling density is used when used in the phosphor slurry. It was possible to greatly improve and the luminance was also improved.

Claims (2)

A color cathode ray tube phosphor comprising a color cathode ray tube phosphor, an ethyl silicate attached to the phosphor, and a hydrolysis agent, wherein the hydrolyzating agent is a urea. The color cathode ray tube phosphor according to claim 1, wherein the amount of the urea is 0.01 to 20% by weight based on 100% by weight of the phosphor for color cathode ray tube.