KR100232577B1 - Photoconductive coating phosphor powder for manufacturing electrophotographical screen of crt and coating method of phosphor powder thereof - Google Patents

Abstract

The present invention provides a powdered phosphor for producing a dry electrophotographic screen of a cathode ray tube having excellent chargeability and fluidity and excellent conductivity at exposure, and a coating method thereof.

The phosphor particles have a 1% by weight photoconductive film formed on the surface thereof. In addition, the photoconductive film coating method of the present invention is bisdimethyl phenyl diphenyl butatriene in toluene or xylene, trinitrofluorenone (TNF) and ethyl anthraquinone (EAQ). Primary dispersion step of dispersing 0.01 to 10% by weight of at least one UV-reactive substance and 1 to 30% by weight of polystyrene as a polymer binder; An addition step of slowly adding the phosphor powder to the primary dispersion; A second dispersion step of dispersing toluene or xylene again in the result of the addition step; 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 sieve step of filtering the resultant dried in the drying step.

Accordingly, the photoconductive film-coated phosphor has superior charging and flow characteristics and excellent conductivity during exposure, thereby improving workability and improving productivity in the screen manufacturing process.

Description

Photoconductive Film Coating Powder Phosphor for Electrophotographic Screen Production of Cathode Ray Tubes and Coating Method of Powder Phosphors

The present invention relates to a powder phosphor for manufacturing a dry electrophotographic screen of a cathode ray tube and a coating method of the powder phosphor, in particular, a screen process is performed by eliminating the intermediate fixing step, charging characteristics, supply by a charging device such as a corona discharger And a photoconductive film-coated powder phosphor for producing a dry electrophotographic screen of a cathode ray tube, which has improved flow characteristics at spraying and conductivity at pre-exposure, and a coating method of the powder 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, and the electron beams 19a and 19b emitted from the electron gun 11 are focused and accelerated by various lens systems, and the anode button 15 It is greatly accelerated by the high voltage applied through the deflection yoke (17) 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 fluorescent 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, and B in a constant array structure are shown. ) And light absorbing material such as black coating between each phosphor. In addition, the rear surface is formed with an aluminum thin film layer 22 as a conductive film layer, which serves to increase the luminance 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 in order to increase the plan view and reflectance of the aluminum thin film layer 22.

The conventional photolithographic wet process in which the fluorescent 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 is high quality. Not only does it not meet the requirements, but the manufacturing process and manufacturing equipment is complicated, the manufacturing cost is large, and also has a number of problems, such as the consumption of large amounts of clean water, wastewater generation, phosphorus emissions, hexavalent chromium photoresist emissions. Recently, an electrophotographic screen manufacturing method has been developed that improves the wet photolithography. In this electrophotographic manufacturing method, the wet still has the above-mentioned problems. It was considerably resolved.

For example, the present application filed "the method for manufacturing a dry electrophotographic screen of a cathode ray tube and a cathode ray tube manufactured thereby" (patent application No. 96-13252 dated 27.27.199) is as follows.

3 (a) to 3 (f) schematically show each process for screen production.

3 (a) or 1-50% by weight of the conductive film 132 coated on the inner surface of the face plate 18, for example, Catfloc-c or Catfloc-CL manufactured by Calgon as polyelectrolyte. And 1-50% by weight of an aqueous 10% PVA solution (the remaining water) are applied by conventional methods and dried. The photoconductive coating solution containing the substance which reacts to an ultraviolet-ray is apply | coated and dried on it. At least one of bisdimethyl phenyl diphenyl butatriene, trinitro-fluorenone (TNF) and ethyl anthraquinone (EAQ) may be used as the material that reacts to ultraviolet rays. As a photocoating coating solution, 0.01 to 10% by weight of UV-reactive substance and 1 to 30% by weight of polystyrene as a polymer binder are dissolved in toluene or xylene, which is the remaining amount. Was used.

FIG. 3 (b) schematically shows a charging process, which charges to 1 KV or less (preferably 700 V to 1 KV volt). In the case of the photoconductive film, the dark room operation is unnecessary because it reacts with ultraviolet rays having a wavelength of 45 nm or less.

3 (c) and 3 (d) schematically show a preliminary exposure process and an exposure process. As shown in FIGS. 3 (c) and 3 (d), the wavelength is short and straight from the ultraviolet light source 138. Excited ultraviolet light passes through the ultraviolet transmission lens 140 and enters the shadow mask 16 at a predetermined angle of incidence, and passes through an aperture or slit 16a of the shadow mask 16 having a predetermined arrangement. While the photoconductive film 134 is exposed in a predetermined arrangement structure, in the case of FIG. 3 (d), the second phosphor P2 is developed in the case of developing the regions of the phosphor fine powders to be developed as in the prior art, and the second phosphor P2. The regions of the phosphor P2 are exposed. At this time, the conductive film 132 is earthed, and the charge of the exposed portion passes through the conductive film 132, and the charge of the non-exposed portion remains in the photoconductive film 134 as it is, so that the second phosphor P2 A latent charge image of a predetermined arrangement for the phenomenon of is formed in the photoconductive film.

In particular, in FIG. 3 (c), regions of the first phosphor P1 already attached to the photoconductive film 134 in the development process described below with respect to the third (e) degree are exposed. In other words, in the preliminary exposure step, the photoconductor film is made to have the same charge in the region of the photoconductor film to which any of the fluorescent film-constructed fine powders are attached to the same as the charge in the region of the photoconductor film to which the fluorescent surface-constituting fine powder is not attached The photomask is exposed in a predetermined arrangement by passing it through a shadow mask to selectively release the electrostatic charges.

In detail with reference to FIGS. 4 and 5, even when the first phosphor P1 is developed in the developing process but is not fixed, the second phosphor P2 is charged at a constant voltage in the charging process. In the state where the first phosphor P1 is attached, the charged state is not uniform as shown in FIG. 6 (b). That is, in the part where the first phosphor P1 is not attached, the potential becomes VO, but in the part where the first phosphor P1 is attached, the potential is formed from the polymethyl methacrylate formed in the first phosphor P1 ( PMMA) and the secondary film of polyacrylamide (PAA), that is, the insulating coating film, have a potential higher than VO (VH), which is directly exposed to the exposure process of FIG. As shown in FIG. 2, since the potential VL of the portion to which the second phosphor P2 is to be attached becomes relatively lower than that of the first phosphor coating region, the first phosphor P1 charged and not fixed to the high potential VH is not fixed. Particles are developed into the second phosphor P2 attaching region as shown by the arrows in some fourth (c) diagrams, and the color purity of the screen is greatly deteriorated even after the second phosphor P2 is developed. .

To solve this problem, after the first phosphor P1 is developed, the preexposure process of FIG. 3 (c) should be performed between the charging process of FIG. 3 (c) and the exposure process of FIG. 3 (d). At this time, although the first phosphor P1 region is charged as shown in FIG. 4 (a) and has a high potential VH as shown in FIG. 4 (b), the preliminary exposure process is performed through the preexposure process. As shown in (b), it becomes a uniform electric potential VO, and only the 2nd phosphor P2 area | region is shown in FIG. 4 (c) (d) through the exposure process of FIG. 3 (b). This latent charge VL is obtained, so that the development can be performed only by the second phosphor P2 in the developing process without the development of the first cavity P1.

3 (e) schematically shows a developing process. Conventionally, as described above, in the developing process, the carrier beads and the phosphor particles or the light absorbing material particles are mixed to charge static electricity by friction, but in the above-mentioned application, fine particles such as phosphor powder or light absorbing material powder having an insulating coating film are formed. The powder is sprayed by the air pressure from the hopper 148 through the venturi tube 146 through the discharge electrode 144a and the nozzle 144b, such as a corona discharge device, to charge the fine powder and to discharge the photoconductive film 134. It adheres to either an exposed part or a non-exposed part. The polarity of the static electricity charged by the fine electrode by the discharge electrode 144a is determined by whether the fine powder is attached to the exposed portion or the non-exposed portion in the exposure process. In other words, the fine powder is charged to the negative charge (positive phenomenon) when attached to the non-exposed part having a positive charge, and the fine powder is charged to the positive charge when attached to the exposed part where the charge is released (reverse phenomenon). 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 (f) schematically shows a fixing process using vapor swelling method. In this step, at least the photoconductive film 134 is sprayed with solvent vapor such as acetone or methyl isobutyl ketone on the surface of the photoconductive film 134 to 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. Therefore, since there is no need to heat and fuse by infrared rays etc. conventionally, a heating apparatus and a lot of energy are unnecessary.

6 is a flowchart showing an example in which the above-described basic processes are applied to the production of R, G and B phosphor screens of color cathode ray tubes.

First, step S101 is the primary coating step, step S102 is the secondary coating step, the material sensitive to ultraviolet rays on the conductive film 132 and the conductive film 132 as described above with respect to the third (a). The photoconductive film 134 including the coating is coated. After coating in this manner, in order to attach the first phosphor, the photoconductive film 134 is charged as in FIG. 3 (b) in step S103. Subsequently, step S104 is a first exposure step in which a predetermined first phosphor array structure is exposed by the exposure step in FIG. 3 (d), and the photoconductive film 134 thus exposed in accordance with the present invention in step S105. Only the exposed portion is developed by the first phosphor fine powder by the developing step of FIG. 3 (e). When the first phosphor is attached in a desired arrangement in step S105, which is the first development step, the photoconductive film 134 to which the first phosphor is attached is recharged, i.e., 2, in the second charging step, step S106, for the second phosphor. Charge the car. Thereafter, the first phosphor attaching portion is subjected to the first preliminary exposure in steps S107 and the second exposure and development are carried out for the second phosphor in steps S108 and S109, and similarly, the third charging is performed in step S110 for the third phosphor. do. After the tertiary charging is performed, the first and second phosphor attaching portions are subjected to the second preliminary exposure in step S111, and the third exposure and development are performed for the third phosphor in steps S112 and S113, followed by step 114. In the first to third phosphors are fixed on the photoconductive film 134 by the fixing process of the third (f). In the pre-exposure step S111 of the first and second phosphor attaching portions for attaching the third phosphor described above, since the first and second phosphors are already attached in the case of a dot-type screen, they are in electrical equilibrium in a charged state. Even if the state of charge is uneven, preliminary exposure for this is unnecessary.

Thereafter, a lacquer is applied in step S115 according to a conventional method, and an aluminum film is formed in step S116. As such, the panel 12, which has undergone the anodizing process (S114), is heated at a high temperature in step S117 to remove other volatile substances such as the conductive film 132, the photoconductive film 134, and the phosphors are fixed to obtain a desired screen.

Although the above-described "method of manufacturing the screen of the cathode ray tube" filed by the present applicant has been described, in the pre-exposure process of FIG. 3 (c), the higher than the potential (VO) of other parts due to the insulating coating film of the phosphor powder. Drop the potential VH of the portion to which the first or second phosphors P1 and P2 are charged in the secondary or tertiary charging process with the potential VH to the same potential VO as the other portions. In order to solve this problem, at least 30 seconds to 2 minutes are required due to the insulating coating film.

In addition, simply forming a primary film of polymethyl 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.

Accordingly, an object of the present invention is to provide a powder phosphor for dry electrophotographic screen manufacturing of a cathode ray tube and a coating method thereof having excellent chargeability and fluidity, and excellent conductivity during exposure.

1 is a schematic plan view of a 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 (f) are schematic diagrams for explaining a dry electrophotographic screen manufacturing process.

4 (a) to 4 (d) are schematic diagrams for explaining the charging state after the first phosphor development and the exposure state for the second phosphor development.

5 (a) to 5 (d) are schematic diagrams for explaining the charged state after preliminary exposure and the exposure state for the second phosphor development.

6 is a process chart for producing a color cathode ray tube by a dry electrophotographic screen manufacturing method.

Figure 7 (a) is a cross-sectional view of the powder phosphor particles according to the present invention and Figure 7 (b) is a schematic diagram for explaining the pre-exposure process for screen production according to the present invention.

* Explanation of symbols for main parts of the drawings

10 cathode ray tube (CRT) 11 electron 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: light absorbing material

22: aluminum thin film layer 132: conductive film

134: photoelectric film 138: ultraviolet light source

140: ultraviolet lens 142: developing container

144a: discharge electrode 144b: nozzle

146: Venturi tube 148: Hopper

P1: first phosphor P2: second phosphor

In order to achieve this object, the present invention is characterized in that the electron beam of the cathode ray tube, characterized in that 1% by weight of the photoconductive film is formed on the particle surface of the dry powder phosphor used in the dry electrophotographic screen production of the panel of the cathode ray tube Provided is a photoconductive film-coated powder phosphor for photographic screen production.

Since the photoconductive film is preferably conductive in response to the light source used in the exposure process, when using an ultraviolet light source, bisdimethyl phenyl diphenyl butatriene and trinitroflu are used as ultraviolet light reactants. 0.01 to 10% by weight of UV-reactant and at least one of 30% by weight of polystyrene as at least one of trinitro-fluorenone (TNF) and ethyl anthraquinone (EAQ). It is preferable to contain.

In addition, the present invention is a method for coating a photoconductive film of a powder phosphor used in the manufacture of a dry electrophotographic screen of a cathode ray tube, comprising: bisdimethyl phenyl diphenyl butatriene in toluene or xylene; 0.01 to 10% by weight of at least one UV-reactive substance in trinitro-fluorenone (TNF) and ethyl anthraquinone (EAQ) and 1 to 30% by weight of polystyrene as a polymer binder Primary dispersion step of dispersing); An addition step of slowly adding the phosphor powder to the primary dispersion; A second dispersion step of dispersing toluene or xylene again in the result of the addition step; 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 photoconductive film coating method of the powdered phosphor for dry electrophotographic screen manufacturing of the cathode ray tube, characterized in that it comprises a sieve step of filtering the resultant dried in the drying step.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. First, the photoconductive film coating powder phosphor particles are shown in FIG.

In FIG. 7, the photoconductive film C is formed in the phosphor particles P about 1% by weight of the phosphor particles P around the surface thereof.

The photoconductive film (C) has the same composition as the photoconductive film (134) and includes bisdimethyl phenyl diphenyl butatriene, trinitro-fluorenone (TNF) and ethyl. At least one or more of an anthraquinone (ethylanthraquinone: EAQ) is formed from 0.01 to 10% by weight of UV-reactant and 1 to 30% by weight of polystyrene as a polymer binder.

One embodiment of the above-described photoconductive film (C) coating method is as follows.

First, at least one of 0.01 to 10% by weight of bisdimethyl phenyl diphenyl butatriene and at least one of trinitro-fluorenone (TNF) and ethyl anthraquinone (EAQ). 1 to 30 wt% of polystyrene is dispersed in 1 L of toluene or xylene as a UV-reactant and a polymer binder. This dispersion step is preferably by ultrasonic dispersion.

Subsequently, 1Kg of phosphor powder is slowly added to the silica in which silica is dispersed, and 0.5L of toluene or xylene is 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 sieving of about 400 mesh is obtained to obtain a phosphor coated with a desired photoconductive film C, as shown in FIG.

On the other hand, the PMMA secondary film (PM) and PAA primary film (PA) may be formed by a conventional method in order to further improve the chargeability to the phosphor particles (P). In this case, a photoconductive film C is formed thereon.

The phosphor obtained in this way has excellent charging and flow characteristics, so that the phosphor powder can be easily sprayed or sprayed from the hopper through the nozzle in the developing process of FIG. 3 (e), and can be easily charged by the discharge means. In the preliminary exposure process of FIG. 3 (c) described above, the potential VH of the portion to which the first or second phosphors P1 and P2 are charged in the secondary or tertiary charging process is uniformly equal to the other portions. It takes only 30 seconds or less to drop to one potential (VO), so it is excellent in workability in the screen manufacturing process, and also in the baking process, which is the final screen process, to remove the photoconductive film (C). It has a superior effect.

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

Claims (5)

A photoconductive film-coated powder phosphor for producing an electrophotographic screen of a cathode ray tube, characterized in that a photoconductive film is formed on a particle surface of a dry powder phosphor used for manufacturing a dry electrophotographic screen on a panel inner surface of a cathode ray tube. The method of claim 1, wherein the photoconductive film is about 1% by weight of the phosphor weight, and is bisdimethyl phenyl diphenyl butatriene as a UV-reactive substance, and trinitrofluorenone: TNF) and ethyl anthraquinone (EAQ) of at least one or more 0.01 to 10% by weight of the UV-reactive substance and a polymer binder, characterized in that it contains 1 to 30% by weight of polystyrene Photoconductive film coating powder phosphor for dry electrophotographic screen production of cathode ray tube. In the photoconductive film coating method of the powdered phosphor used in the manufacture of dry electrophotographic screen of cathode ray tube, bisdimethyl phenyl diphenyl butatriene and trinitrofluorinone in toluene or xylene -Fluorenone (TNF) and ethyl anthraquinone (EAQ) of 0.01 to 10% by weight of at least one UV-reactive substance and 1 to 30% by weight of polystyrene as a polymer binder (polystyrene) to disperse Dispersion step; An addition step of slowly adding the phosphor powder to the primary dispersion; A second dispersion step of dispersing toluene or xylene again in the result of the addition step; 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 sieve step of sieving the resultant dried in the drying step. The photoconductive film coating method of the powder phosphor for dry electrophotographic screen manufacturing of a cathode ray tube. The method of claim 3; The first dispersion step and the second dispersion step are dispersed by ultrasonic waves; The filtering step is filtering by a glass frit filter; The drying step is a method for coating a photoconductive film of a powder phosphor for dry electrophotographic screen manufacturing of a cathode ray tube, characterized in that the drying step for about 3 to 5 hours at 100 ℃ or less. [5] The powder phosphor for dry electrophotographic screen production of cathode ray tubes according to claim 3 or 4, wherein the phosphor powder applied in the addition step is formed of a polymethyl methacrylate primary film and a polyacrylamide secondary film. Photoconductive film coating method.