KR19990027065A - Method for manufacturing dry electrophotographic screen of cathode ray tube - Google Patents

Abstract

The present invention provides a method for producing a dry electrophotographic screen of a cathode ray tube.

The method for manufacturing a dry electrophotographic screen includes: (1) a coating step of forming a volatile conductive film 132 on an inner surface of the panel 12 and forming a volatile photoconductive film 134 on the conductive film 132; (2) a charging step of charging the photoconductive film 134 with a uniform electrostatic charge; (3) an exposure step of exposing through the shadow mask 16 to selectively release the electrostatic charge of the photoconductive film 134; (4) a cathode ray tube including a developing step of attaching one of the first to third phosphors to the fine powder of the light absorbing material in one of the exposed portion and the non-exposed portion of the photoconductive film 134. A method for manufacturing a dry electrophotographic screen of claim 1, wherein in the coating step, a volatile sidewall portion conductive film 132 ′ is further formed on the photoelectric film 134 of the sidewall portion 12 ′ of the panel 12. It is done.

Accordingly, in the charging step, the photoconductive film 134 of the side wall portion of the panel 12 cannot be charged, so that the phosphors can be developed at a uniform developing density even at the boundary portion A of the effective screen portion E. FIG. have.

Description

Method for manufacturing dry electrophotographic screen of cathode ray tube

The present invention relates to a method for manufacturing a dry electrophotographic screen of a cathode ray tube, and more particularly, in the developing process of a method for manufacturing a dry electrophotographic screen, the photoelectric film of the side wall portion of the panel cannot be charged in the charging step. The present invention relates to a method for manufacturing a dry electrophotographic screen of a cathode ray tube capable of developing phosphors at a uniform developing density at the boundary of an effective screen portion.

Generally, a 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 inside the neck 14. And an shadow gun 16 mounted inside the panel 12.

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 arrangement structure are shown. And a light absorbing material 21 such as a black coating between the respective phosphors. In addition, the rear surface of the aluminum thin film layer 22 is formed as a conductive film layer, which serves to increase the luminance of the fluorescent screen, to prevent ion damage of the fluorescent screen, and to prevent the potential drop of the fluorescent screen. In addition, in order to increase the top view and reflectance of the aluminum thin film layer 22, a resin film layer 22 'made of a resin such as lacquer is formed between the fluorescent surface 20 and the aluminum thin film layer 22 which is a conductive film layer. This resin film layer 22 'is combusted and volatilized for the life of the tube after formation 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 of high quality. Not only does it not meet the requirements, but the manufacturing process and the manufacturing equipment is complicated, the manufacturing cost is large, and also, there are many problems such as the consumption of large amounts of clean water, wastewater generation, phosphorus emissions, hexavalent crack photoconductor emissions. Recently, an electrophotographic screen manufacturing method has been developed that improves the wet photolithography. The electrophotographic manufacturing method also has the above-mentioned problems. It was considerably resolved.

A representative method for manufacturing a dry electrophotographic screen is disclosed in US Pat. No. 4,921,767 (patented May 1, 1990). However, in the patent, since the photoconductive film contains dyes reacting with visible light, darkroom operation is inevitable, and energy consumption is considerable because the fixing process is based on infrared heating.

Accordingly, the present applicant solved the above problem by forming the photoconductive film into a photoconductive solution sensitive to ultraviolet rays.

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

3A to 3E schematically show each process according to the above manufacturing method. 3A is a coating process in which the conductive film 132 and the photoconductive film 134 are formed on the 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 film coating solution containing a substance reacting with ultraviolet rays is applied thereon and dried. An example of a material that reacts to ultraviolet light is bis dimethyl phenyl diphenyl butadiene (bis-1, 4-dimethyl phenyl (-1, 4-diphenyl (butatriene)) in an amount of 0.01 to 1% by weight as an electron donor. Or 2 to 5% by weight of tetraphenylethylene and at least one or more of trinitro-fluorenone (TNF) and ethyl anthraquinone (EAQ) each as an acceptor. To 1% by weight was used by dissolving in 1 to 30% by weight of polystyrene (PS) as a polymer binder in toluene or xylene which is the remaining amount. In addition to the polystyrene as the polymer binder, polyalphamethylstyrene (poly (α-methylstyrene: PAMS), polymethylmethacrylate (PMMA) and polystyrene-oxazoline copolymers (PS-OX) ) May be used.

3B schematically shows a charging process. A DC voltage of + 1K volts or less, preferably +700 volts or more was applied to charge the corona discharge device 36. Since the photoconductive film 134 reacts with ultraviolet rays having a wavelength of at least 450 nm or less, darkroom operation is unnecessary.

FIG. 3C schematically illustrates an exposure process, in which ultraviolet light from the ultraviolet light source 138 passes through the ultraviolet transmission lens 140 and enters the shadow mask 16 at a desired angle of incidence, and has a desired shadow mask. Is the photoconductive film 134 exposed in a desired arrangement through the aperture or the slit 16a hole of (16)? 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 also uses the ultraviolet light source 138, it is not necessary to work in a dark room.

Fig. 3D schematically shows the developing process. Conventionally, in this development step, the carrier beads and the phosphor particles or the light absorbing material particles are mixed to charge static electricity by friction, but according to the present invention, the fine powder such as the powder of the phosphor powder or the light absorbing material is 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 non-exposure. Attach to either 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 -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 micropowder 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 repulsion.

Figure 3e schematically illustrates a fixing process using a liquid electrostatic spray gun. In this step, petroleum-based xylene, toluene, TCE, methyl isobutyl ketone (MIBK) are formed 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. By spraying a solvent such as), at least the polymer contained in the photoconductive film 134 is dissolved, and the micropowder (s) attached by the action of electric force by the adhesive force of the dissolved polymer are fixed. In this fixing process, a vapor swelling method of fixing fine powders developed by contacting solvent vapors such as acetone and methyl isobutyl ketone may be used, and by infrared heating as in US Pat. No. 4,921,767. May be performed.

The above-described processes are repeated for three kinds of phosphors for the production of the color cathode ray tube. In addition, the light absorbing material of the black matrix may also be formed as described above before or after the attachment of the three phosphors.

In this way, after the phosphor and the light absorbing material are formed, a lacquer film is formed by a conventional method in a lacquer process, and an aluminum thin film is also formed by a conventional method in an anodizing process, which is then introduced into a baking process and introduced into the atmosphere. By heating and drying at 425 DEG C for about 30 minutes, the volatile components such as the conductive film 132, the photoconductive film 134, and the polymers present in each phosphor and lacquer are burned and removed, and the light absorbing material 21 and each phosphor ( A fluorescent surface 20 is obtained in which R, G, and B are formed as shown in FIG.

However, in the developing process (FIG. 3D) of the above processes, as shown in FIG. 4, due to the charges charged in the photoconductive film 134 formed in the side wall portion 12 'of the panel 12, In the boundary A of the effective screen portion E, the charged phosphor particles are subjected to a more electrical repulsive force than the inner portion B of the central portion thereof, so that they are not developed or are developed very weakly.

Accordingly, the present invention is to solve the above-described problem, by forming a sidewall portion conductive film for preventing charging in the sidewall portion of the panel, the phosphor particles at a predetermined predetermined density even at the boundary of the effective screen portion of the panel It is an object of the present invention to provide a method for manufacturing a dry electrophotographic screen of a cathode ray tube that can be developed.

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

2 is a partially enlarged cross-sectional view showing a screen configuration of the cathode ray tube of FIG. 1;

3A to 3E are schematic views for explaining a dry electrophotographic screen manufacturing method,

4 is a partial cross-sectional view illustrating a developing process in a side wall portion of a panel in a conventional developing process;

5 is a process diagram schematically showing the sidewall portion exposing step for releasing charges in the sidewall portion in accordance with one embodiment of 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 bipolar 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 36: charging device

132: conductive film 134: photoconductive film

138: light source 140: lens

142: developing container 142a: grid electrode

144a: discharge electrode 144b: nozzle

132 ': sidewall conductive film

In order to achieve this object, the present invention, (1) forming a volatile conductive film on the inner surface of the panel, and forming a volatile photoconductive film on the conductive film; (2) a charging step of charging the photoelectric film with a uniform electrostatic charge; (3) an exposure step of exposing through a shadow mask to selectively release the electrostatic charge of the photoconductive film; (4) dry electrons in a cathode ray tube including a developing step of attaching one of the first to third phosphors, the fine powder of the light absorbing material, to a region of either the exposed portion or the non-exposed portion of the photoconductive film; In the method of manufacturing a photographic screen: The method of manufacturing a dry electrophotographic screen of a cathode ray tube, characterized in that further forming a volatile conductive film on the photoconductive film of the side wall portion of the panel in the coating step.

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

5 is a schematic process diagram of a coating step according to an embodiment of the present invention.

In the coating step shown in FIG. 5, as shown in FIG. 3A, after the conductive film 132 and the photoconductive film 134 are formed on the inner surface of the face plate 18, the sidewalls are formed over the entire inner circumference of the panel 12. The sidewall portion conductive film 132 'on the light source 150 is formed in the.

The sidewall portion conductive film 132 ′ may be formed of the same material as the conductive film 132 as described above with reference to FIG. 3A. For example, the sidewall portion conductive film 132 'is a polyelectrolyte, which is an aqueous solution of 10% PVA solution of 1-50% by weight and 1-50% by weight of Catfloc-c manufactured by Calgon. Water) is applied by a conventional method and dried.

The panel 12 on which the conductive film 132, the photoconductive film 134, and the sidewall portion conductive film 132 'are formed is charged with the corona discharge device 36 as shown in FIG. 3B. In the effective screen portion E, the photoconductive film 134 is charged and in the sidewall portion 12, the sidewall portion conductive film 132 ′ is charged, but the charges charged in the sidewall portion conductive film 132 ′ are transferred to the conductive film. Since 132 is in an earthed state, it is released immediately after charging.

The panel 12 charged as described above is exposed to the shadow screen 16 through the shadow mask 16 at a predetermined latent charge array structure in the effective screen portion E in the exposure step of FIG. 3C, and the charged phosphor R in the developing step of FIG. 3D. , G, B) to develop a fine powder of the light absorbing material (21). At this time, the effective screen portion E forms a predetermined latent charge image, but since the charge is released in the sidewall portion conductive film 132 ', the side wall portion 12' is not the effective screen portion (Fig. 4). There is no electrical influence on the boundary A of E).

As a result, the equipotential lines are formed in the boundary portion A or the inner portion B of the central portion in the same manner, so that the developing density can be made uniform.

Subsequently, when the panel 12 introduced in the coating step has a black matrix structure of a light absorbing material, the charging step and the developing step are repeated for the remaining phosphors in the phosphors R, G, and B. By attaching all three phosphor particles to the photoconductive film so that all three phosphors R, G, and B are uniform over the entire area of the effective screen portion E without electrical influence of the side wall portion 12 '. It is possible to maintain a developing density.

The panel 12 put into the coating step may be a black matrix structure of the light absorbing material 21 formed by a wet screen manufacturing method as in the prior art, or as described above by the method of manufacturing a dry electrophotographic screen. All of the fine powder of the light absorbing material 21 may be attached to the photoconductive film.

Thereafter, a fixing step is performed in which the fine powders of the three color phosphors R, G, and B to the light absorbing material 21 developed on the photoconductive film 134 are firmly fixed to the photoconductive film 134. As described above with reference to FIG. 3E, the resin film layer 22 is formed on the photoconductive film 134 on which the fine powders of the three-color phosphors R, G, and B to the light absorbing material 21 are firmly fixed. ') And the aluminum thin film layer 22 are formed, and then a post-treatment step of baking is performed to burn volatile components such as the conductive film 132, the photoconductive film 134, and polymers present in the phosphors and lacquers. A fluorescent surface 20 is obtained in which the light absorbing material 21 and each phosphor R, G, and B are removed as shown in FIG. At this time, the obtained phosphor surface 20 has the same density as that of the phosphors R, G, B and the light absorbing material 21 at the boundary portion A of the effective screen portion E, as in the inner portion B of the central portion. Will be formed.

On the other hand, the above-described developing step is a fine powder such as a triboelectric charging method or a fluorescent material disclosed in the above-mentioned US Patent No. 4,921,767, in addition to the method of charging the fine powder by corona discharge immediately before being ejected by the spray coater as shown in Figure 3d The present invention can also be applied even when developed by a method of rubbing and charging with a pipe in the process of supplying.

In addition, the adhesion process of Figure 3e, even when the solvent is sprayed by the liquid electrostatic spray method of the mixed solvent according to the present invention, the adhesion is stronger, but vapor swell to contact and fix the solvent vapor such as acetone, methyl isobutyl ketone It is also possible to use a swelling method.

As described above, according to the configuration and operation of the method for manufacturing a dry electrophotographic screen of a cathode ray tube according to the present invention, in the method of manufacturing a dry electrophotographic screen of a cathode ray tube, a sidewall portion conductive film ( 132 ′), the phosphor particles can be developed at a predetermined predetermined density even at the boundary A of the effective screen portion E of the panel 12.

Claims (1)

(1) a coating step of forming a volatile conductive film 132 on the inner surface of the panel 12 and forming a volatile photoconductive film 134 on the conductive film 132; (2) a charging step of charging the photoconductive film 134 with a uniform electrostatic charge; (3) an exposure step of exposing through the shadow mask 16 to selectively release the electrostatic charge of the photoconductive film 134; (4) a cathode ray tube including a developing step of attaching one of the first to third phosphors to the fine powder of the light absorbing material in one of the exposed portion and the non-exposed portion of the photoconductive film 134. In the method for producing a dry electrophotographic screen of; In the coating step of the dry electrophotographic screen of the cathode ray tube, characterized in that to further form a volatile side wall portion conductive film 132 'on the photoconductive film 134 of the side wall portion 12' of the panel 12. Manufacturing method.