KR100216229B1 - Fluorescent material and manufacturing method for crt screen and crt - Google Patents

Abstract

Disclosed are a silica-dispersed coating phosphor having improved flow characteristics, a method of manufacturing the same, and a cathode ray tube having the fluorescent body. A first dispersion step of dispersing silica in methanol, an addition step of slowly adding phosphor powder to methanol in which the silica is dispersed, a second dispersion step of dispersing methanol again in the methane to which the silica is dispersed and the phosphor powder is added, and A filtering step of filtering the result of the second dispersion step, a drying step of drying the filtered result in the filtering step, and a sieving step of sieving the dried resultant in the drying step. It provides a silica dispersion coating phosphor characterized in that the silica is dispersed and coated on the particle surface of the dry powder phosphor used for the production of the screen of the cathode ray tube panel inner surface, further comprising a phosphor dispersed and coated on the particle surface of the silica The screen is formed. The weight of silica dispersed and coated is preferably 0.1 to 0.5% of the weight of the phosphor. As a result, the flow characteristics are excellent and do not easily adhere to the phosphors or other materials, so the workability is excellent in the above-described screen manufacturing process. It is also excellent for removing volatiles.

Description

Phosphor for screen production of cathode ray tube and its manufacturing method and cathode ray tube having the phosphor

1 is a schematic front view in partial cross section of a color cathode ray tube;

2 is a partially enlarged cross-sectional view showing the screen configuration of the cathode ray tube of FIG.

3 (a) to 3 (e) schematically illustrate a dry electrophotographic screen manufacturing process for manufacturing a screen of a cathode ray tube using the phosphor of the present invention.

Figure 4 (a) is an enlarged view of the phosphor particles according to an embodiment of the present invention for producing a screen, (b) is an enlarged view of the phosphor particles according to an embodiment of the present invention constituting the screen.

* Explanation of symbols for main parts of the drawings

10: cathode ray tube (CRT) 11: gun gun

12: panel 13: funnel

14 neck 15 anode button

16: shadow mask 17: deflection yoke

18: panel face plate 19a, 19b: electron beam

20: fluorescent screen (screen) 21: debt absorbing material

22: aluminum thin film layer 36: corona discharge device

132: conductive film 134: photoconductive film

138: ultraviolet light source 140: ultraviolet lens

142: developing container 144a: discharge electrode

144b: Nozzle 146: Venturi tube

148 hopper P: phosphor particles

PA: PAA 1st barrier PM: PMMA 2nd barrier

SC: Silica Coating

The present invention relates to a phosphor coating of a cathode ray tube, and more particularly, to a silica dispersion coated phosphor having improved flow characteristics, a method of manufacturing the same, and a cathode ray tube having the phosphor.

In general, the cathode ray tube, as shown in FIG. 1, has a vacuum bulb divided into a panel 12, a funnel 13 and a neck 14, and the neck 14 thereof. An electron gun 11 mounted therein and a shadow mask 16 mounted on the side wall of the panel 12 are provided.

A fluorescent surface 20 is formed on the inner surface of the face plate 18 of the panel 12. The electron beams 19a and 19b emitted from the electron gun 11 are connected and accelerated by various lens systems, and the anode button ( It is greatly accelerated by the high voltage applied through 15) and deflected by the deflection yoke 17 and passed through the apertures or slits 16a of the shadow mask 16 to the fluorescent surface 20.

The matt surface 20 is formed on the back surface of the face plate 18. In the case of the color, as shown in FIG. 2, a plurality of stripe or dot-shaped phosphors R, G, It is formed of a light absorbing material such as black coating between B) and its respective phosphors. In addition, the rear surface is formed with an aluminum thin film layer 22 as a conductive film layer to increase the intensity of the fluorescent surface, to prevent ion damage of the fluorescent surface, and to prevent the potential drop of the fluorescent surface. Although not shown, a resin such as lacquer is applied between the fluorescent surface 20 and the aluminum thin film layer 22, which is the conductive film layer 22, in order to increase the top view and reflectance of the aluminum thin film layer 22.

Conventional photolithographic wet process, in which the fluorescence surface 20 is formed by applying and drying a suspension containing fluorescent particles such as a chromophoric phosphorus component or a suspension containing a light absorbing material, In addition, it does not meet the requirements of high-definition, the manufacturing process and the manufacturing equipment is complicated, the manufacturing cost is large, and also has a number of problems, such as the consumption of large quantities of clean water, wastewater generation, phosphorus emissions, hexavalent chromium photoresist emissions. Recently, an electrophotographic screen manufacturing method has been developed that improves the wet lithography. The electrophotographic manufacturing method also has the above-mentioned problems, and the dry manufacturing method has the problems described above. It was considerably resolved.

As an example, a description will be given of the screen manufacturing method of the cathode ray tube filed by the present applicant as follows.

3 (a) to (e) schematically show each process according to the above manufacturing method. FIG. 3A illustrates a coating process in which a conductive film 132 and a photoconductive film 134 are formed on an inner surface of the face plate 18. The conductive film 132 is a polyelectrolyte, for example, a conventional solution of 1-50% by weight of Catfloc-c and 1-50% by weight of 10% PVA solution (water remaining) manufactured by Calgon. It is formed by application and drying by a method. A new photoconductive coating solution containing a substance reacting with ultraviolet rays is applied thereon and dried. At least one of bis dimethylphenyl diphenyl butatriene, trinitronuorenone (TNF), and ethyl anthraquinone (EAQ) was used as a material that reacts to ultraviolet rays. As the photoconductive coating solution, toluene or xylene having a balance of 0.01 to 10% by weight of bisdimethyl phenyl diphenyl butytriene and 1 to 30% by weight of polystyrene as a polymer binder (bi) nder. It was used by dissolving in (xylene).

3B schematically shows the charging process. A DC voltage of + 1K volts or less, preferably +700 volts or more was applied to charge the corona discharge device. Since the epoch conductive film 134 reacts with ultraviolet rays having a wavelength of at least 450 nm or less, darkroom operation is unnecessary.

FIG. 3 (c) schematically illustrates the exposure process, wherein ultraviolet light having a short wavelength and straightness from the ultraviolet light source 138 passes through the self-transmitting lens 140 and the shadow mask 16 at a desired angle of incidence. The photoconductive film 134 is exposed in a desired arrangement through the aperture or the slit 16a hole of the shadow mask 16 having a desired arrangement. At this time, the conductive film 132 is earthed, and the charge of the exposed portion is discharged through the conductive film 132. The charge in the non-exposed portion remains in the photoconductive film 134 as it is.

Since this exposure process uses the ultraviolet light source 138, it is not necessary to work in a dark room.

3 (d) schematically shows a developing process. Conventionally, in this development step, carrier beads and phosphor particles or light absorbing material particles are mixed to charge static electricity by friction. However, according to the present invention, fine powders such as phosphor powder or powder of light absorbing material are applied by air pressure. From the hopper 148 through the venturi tube 146 through the discharge electrode 144a, such as a corona discharge device and the nozzle 144b, the fine powder is charged and the exposed portion of the photoconductive film 134 and the non-exposure. Attach to either part. The polarity of the static electricity charged to the fine powder by the discharge electrode 144a is determined depending on which portion of the exposed portion and the non-exposed portion species in the exposure process is to be attached to the fine powder. In other words, the fine powder is charged to -charge when attached to the non-exposed portion that is positively charged, and the fine powder is charged to + charge when attached to the exposed portion where the charge is released. The charged fine powder injected into the developing container 142 is strongly attached to the surface of the photoconductive film 134 in a desired arrangement by the action of electrical attraction and repulsive force.

FIG. 3 (e) schematically shows a fixing process according to the applicant's invention using vapor swelling method. In this step, at least the photoconductive film 134 is squeezed by a solvent vapor such as acetone and methyl isobutane ketone on the surface of the photoconductive film 134 in which the desired fine powder (s) are attached in a desired arrangement in the developing step. The polymer contained therein is dissolved and the micropowder (s) attached by electrophoresis are fixed by the adhesion of the dissolved polymer.

The screening method of the cathode ray tube filed by the applicant described above has been described, in which the phosphor powder flows from the hopper 148 to the venturi tube 146 as in the developing process of FIG. At the same time, when the phosphor powder is injected into the air pressure through the venturi tube 146, a large liquidity is required for the phosphor powder.

However, simply forming a primary film of poly methyl methacrylate (PMMA) and a secondary film of poly acrylamide (PAA) in order to impart charging characteristics to the phosphor powder does not have sufficient flow. There is a problem of sticking to a container or the like.

In addition, in the development process in US Pat. No. 4,921,767, a triboelectric powder is used to charge a phosphor powder, and the charged phosphor powder is attached to a photoconductor film. ) And phosphor powder.

Accordingly, the present invention has been made in view of providing a silica dispersion-coated phosphor for imparting flow characteristics to phosphor powder particles, a method of manufacturing the same, and a cathode ray tube having a screen made of the silica dispersion-coated phosphor in order to solve the above problems. There is this.

In order to achieve the above object, the present invention provides a method for producing a silica powder-coated phosphor in the form of a dry powder to improve the flow characteristics of the phosphor particles used for the modification of the screen of the cathode ray tube panel: dispersing silica in methanol First dispersion step; An addition step of slowly adding the phosphor powder to methanol in which the silica is dispersed; A second dispersion step of dispersing the methanol again in methanol to which the silica is dispersed and the phosphor powder is added; A filtering step of filtering the result of the second dispersion step; A drying step of drying the filtered result in the filtering step; And it provides a silica dispersion coating phosphor manufacturing method comprising a sieve (sieving) step of sifting the resultant dried in the drying step.

In addition, the present invention provides a silica dispersion coating phosphor, characterized in that silica is dispersed and coated on the particle surface of the dry powder phosphor used for the production of the screen of the cathode ray tube panel inner surface, furthermore, silica is dispersed and coated on the particle surface Also provided is a cathode ray tube, characterized in that a screen is formed comprising a phosphor.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

First, silica dispersion coating phosphors are shown in FIGS. 4 (a) and 4 (b).

FIG. 4 (a) shows that the PMMA secondary film PM and the PAA primary film PA are formed by a conventional method in order to improve the chargeability of the phosphor particles P, and the colorless transparent silica coating SC is dispersed thereon. Is formed.

FIG. 4 (b) shows the silica dispersion-coated phosphor particles of FIG. 4 (a) in the above screen manufacturing process to form a screen, and then forms an aluminum layer 21 by a conventional method, followed by baking ( It illustrates a phosphor particle from which volatile materials such as the conductive film 12, the photoconductive film 134, PAA, and PMMA have been removed by baking. In this phosphor, colorless and transparent silica coating (SC) is dispersed and formed.

One embodiment of the method of manufacturing the silica dispersion coating phosphor described above is as follows.

First, 1 g of silica is dispersed in 1 L of methanol. This dispersion step is preferably by ultrasonic dispersion.

Thereafter, 1 Kg of phosphor powder was slowly added to the silica in which silica was dispersed, and 0.5 L of methanol was further dispersed. Also in this case, it is dispersed by ultrasonic waves.

The resultant is then filtered with a glass frit filter, then dried at 60-80 ° C. for 2 to 3 hours before entering the sieving step.

In this sieving step, a screen of about 400 mesh is sieved to obtain a phosphor in which the desired silica is dispersed and coated as shown in FIG.

Phosphors obtained in this way have excellent flow characteristics and do not easily adhere to each other or other materials, and thus have excellent workability in the above-described screen manufacturing process, and also disperse silica in the baking process as a screen final process. The coating is excellent for removing volatiles.

Therefore, even in a baking process, heating time and temperature can be shortened, and the more preferable fluorescent substance arrangement structure which does not disturb the array boundary of fluorescent substance can be obtained, etc. There are many effects.

While preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and variations may be made by those skilled in the art from the matters described in the claims.

For example, application of the silica dispersion coating phosphor to improve the dispersion characteristics due to the flow characteristics in the suspension is also possible for screen production by conventional wet slurry.

Claims (4)

In the manufacturing method of a silica powder-coated phosphor in the form of a dry powder to improve the flow efficiency of the phosphor particles used in the production of the screen on the inner surface of the cathode ray tube panel, a first dispersion step of dispersing silica in methanol, the silica is dispersed The addition step of slowly adding the phosphor powder to methanol, the secondary dispersion step of dispersing the methanol again in methanol to which the silica is dispersed and the phosphor powder added, the filtering step of filtering the result of the secondary dispersion step, the filtering step in the filtering step Method for producing a silica-coated phosphor, characterized in that it comprises a drying step of drying the resultant, and a sieve step of filtering the resultant dried in the drying step. The method of claim 1, wherein the first dispersion step and the second dispersion step are dispersed by ultrasonic waves, the filtering step is a step of filtering by a glass frit filter, and the drying step is 3 to 5 below 100 ° C. Silica dispersion coating phosphor manufacturing method, characterized in that the step of drying for about time. The method of claim 1 or 2, wherein the phosphor powder added in the adding step is a polymethyl methacrylate primary film (PMMA) and a polyacrylamide difference film (PAA), characterized in that the silica dispersion coating phosphor manufacturing method. In the dry powder phosphor used for the manufacture of the screen of the cathode ray and the panel inner surface, a polymethyl methacrylate primary film (PMMA) and a polyacrylamide secondary film (PAA) are formed on the surface of the particle, followed by silica (SC). Silica dispersion coating phosphor characterized in that the dispersion and coating.