KR100242162B1 - A developing device for manufacturing a dry-type photographical screen of cathode ray tube - Google Patents

Abstract

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

The developing apparatus includes a phosphor supply pipe 150 for supplying a phosphor to the developing container 142 via a venturi tube 146 from the hopper 148; A coater composed of a corona charging electrode and a nozzle (144a) for charging and injecting the phosphor powder at an end of the phosphor supply pipe (150) in the developing ware; And it is characterized in that it comprises a triboelectric charge tube 150 is installed in the middle of the phosphor supply pipe 150 and the electrostatic charge to the phosphor powder by friction with the phosphor powder passing through the inside.

Accordingly, the triboelectric charge tube 150 may be charged in advance, and later, only a low voltage and a short time may be charged from the corona charging electrode 144b of the coater, thereby saving energy and rapidly generating free ions. There is an effect such that it is reduced to not interfere with the phenomenon.

Description

Developing apparatus for manufacturing dry electrophotographic screen of cathode ray tube

The present invention relates to a developing device for manufacturing a dry electrophotographic screen of a cathode ray tube, and in particular, can be easily charged to the phosphor powder not only by a corona discharge device, it can be evenly developed on the photoconductive film on the inner surface of the panel with the phosphor powder. The present invention relates to a developing device for manufacturing a dry electrophotographic screen of a cathode ray tube.

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.

The fluorescent surface 20 is formed in 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 rear 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 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 screen, to prevent ion damage of the fluorescent screen, and to prevent the potential drop of the fluorescent screen. Although not shown, a resin such as a lacquer is applied between the fluorescent surface 20 and the conductive 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 not meet the requirements, 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.

As an example, the following describes the "method of manufacturing a cathode ray tube" filed by the present applicant.

3 (a) to 3 (e) schematically show each process according to the manufacturing method. 3 (a) 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, which is 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 dimethyl phenyl diphenyl butatriene, trinitro-fluorenone (TNF) and ethyl anthraquinone (EAQ) may be used as a material that reacts to ultraviolet rays. As the photoconductive coating solution, 0.01 to 10% by weight of bis dimethyl phenyl diphenyl butytriene and 1 to 30% by weight of polystyrene as a polymer binder (toluene) or xylene (the remaining amount) xylene).

3 (b) 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 photoconductive 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 ultraviolet transmission lens 140 and enters the shadow mask 16 at a desired angle of incidence. The photoconductive film 134 is exposed in a desired arrangement through an aperture or a 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, the carrier beads and the phosphor particles or the light absorbing material particles are mixed to charge static electricity by friction. 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 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 fine powder injected into the developing container 142 is strongly attached to the surface of the photoconductive film 34 in a desired arrangement by the action of electrical attraction and repulsive force.

3 (e) schematically shows a fixing process according to the applicant's invention using a vapor swelling method. In this step, at least the photoconductive film 134 is brought into contact with 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 contacting solvent vapor such as acetone and methyl isobutyl ketone. The polymer contained in) is dissolved and the micropowder (s) attached by electrophoresis are fixed by the adhesion of the dissolved polymer.

As described above, the present inventors have applied for the screening method of the cathode ray tube, which is briefly illustrated as a nozzle 144b in FIG. 3 (e). I'm using a gating device. That is, in FIG. 4, the coating apparatus 30 is located in the center portion of the inside of the frame 32 corresponding to the developing container 142 of FIG.

On top of the frame 32 a panel 12 is loaded and opened so that the inner surface of the panel can be applied or developed. The coating device 30 is composed of a nozzle body 34 and a plurality of nozzle openings (34a), the coating material (coating liquid or coating powder) is supplied under a constant pressure in the lower portion of the nozzle body 34, The nozzle opening 34a is formed on the top of the nozzle body 34 to directly apply or develop the inner surface of the panel 12 on the upper side by spraying (spraying).

The coating apparatus 30 of this type has a problem that it is difficult to form a uniform film over the entire area of the inner surface of the panel 12 because the coating is sprayed directly on the inner surface of the panel 12.

In particular, in the electrophotographic screen manufacturing method, the coating is attached to a portion that should not be developed when the injection (non) pressure is strong, and when the injection (non) pressure is weak, the direction of the nozzle opening 34a, that is, The outer circumferential portion of the panel, or the portion corresponding to the plurality of nozzle openings 34a is very thinly adhered to the coating, and other portions are thickly attached, resulting in uneven film formation.

When the phosphor powder is charged by the corona discharge electrode 144b of the coater in the above-described developing process of FIG. 4 (d), a large amount of free ions are generated, and the space electric field is caused by the cage effect of Faraday. There is a problem that it is difficult to obtain a desired phosphor development density due to the decrease, and a large amount of discharge energy is required. In particular, if the free ions are generated the most in the early stage of the development process and are not removed, the free ions will stick to the photoconductive film 134 inside the panel 12 instead of the charged phosphor powder particles. The developing density by the phosphor is lowered.

Accordingly, an object of the present invention is to provide a developing device for a cathode ray tube which can minimize generation of free ions from a coater for corona discharge and reduce discharge energy.

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

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

3 (a) to 3 (e) are explanatory views schematically showing a dry electrophotographic screen manufacturing process for manufacturing a screen of a cathode ray tube.

4 is a schematic cross-sectional view of a main part of a conventional coating apparatus for panels of cathode ray tubes.

5 is a schematic view showing the main parts of a developing apparatus according to the present invention.

6 is a cross-sectional view of the triboelectric charge tube.

* 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 36: corona discharge device

30, 50: coating device 32, 52: frame

34, 54: nozzle body 34a, 54a: nozzle opening

54b: flow guide surface 54c: opening cover

55: rotor blade 56: bearing

57: supply pipe (or charging device) 57a: nozzle opening for rotary blades

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

In order to achieve this object, the present invention provides a volatile conductive film on the inner surface of the panel and a volatile photoconductive film on the conductive film, and after charging the photoelectric film with electrostatic charge, the electrostatic charge is released from selected regions of the photoconductive film. Attaching the charged fine powder particles to either the selected area or the unselected area, and fixing the fine powder particles attached to the photoconductive film to the photoconductive film. A developing apparatus for manufacturing, comprising: a phosphor supply tube for supplying a phosphor to a developing vessel from a hopper via a venturi tube; A coater composed of a corona charging electrode and a nozzle for charging and injecting the phosphor powder at an end of the phosphor supply pipe in the developing ware; And a triboelectric charging tube which is installed in the middle of the phosphor supply pipe and passes through the inside, and frictionally charges the phosphor powder by electrostatic charge to the phosphor powder. to provide.

When the fluorescent powder is coated dry fluorescent particles of the primary film of polymethyl methacrylate and the secondary film of polyacrylamide so as to have charging characteristics, the material of the triboelectric charging tube is polyethylene, and the charge to the triboelectric charging tube is applied. Emission of is made through the conductive film formed on the outer wall and grounded, and it is preferable that the inner wall surface has a spiral structure so as to increase the contact area to increase the efficiency of frictional charging, so as to increase the charge amount.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the embodiments of the present invention.

Fig. 5 shows a schematic diagram of a main part of a developing apparatus according to the present invention, and Fig. 6 shows one embodiment of a triboelectric charging tube as a cross-sectional view.

The developing apparatus has a phosphor supply pipe 150 for supplying phosphors from the hopper 148 to the developing container 142 via the venturi tube 146 as shown in FIG. 5, and the phosphor supply pipe 150 In the middle of the), the triboelectric charging tube 150 is installed and charged with the electrostatic charge to the phosphor powder by friction with the phosphor powder passing through the inside. In addition, a coater composed of a corona charging electrode 144b and a nozzle 144a is provided at an end portion of the phosphor supply pipe 150 inside the developing container.

In the case of the dry phosphor particles coated with the primary film of polymethyl methacrylate and the secondary film of polyacrylamide so that the above-mentioned phosphor powder has charging characteristics, the material of the triboelectric charge tube 150 is polyethylene. Can be charged with +.

In addition, it is preferable that the spiral wall 151 of the spiral structure is formed on the inner wall surface as shown in FIG. 6 so as to increase the contact area to increase the efficiency of frictional charging.

In addition, although not shown, a conductive film is formed on the outer wall of the triboelectric charging tube 150, and the conductive film is earthed, thereby easily discharging the electrostatic charges charged to the triboelectric charging tube 150 to charge the phosphor powder. It is also possible to increase the.

According to the developing apparatus for manufacturing a dry electrophotographic screen of the cathode ray tube of the present invention configured as described above, the operation is as follows.

Forming a volatile photoconductive film including a volatile conductive film and a polymer on the conductive film on the inner surface of the panel, charging the photovoltaic film and then electrostatic charge is discharged from the selected areas of the photoconductive film and the selected area and selection In the developing step of attaching the charged fine powder particles to any one of the regions that are not in the region, the phosphor particles flowing through the inside of the triboelectric charge tube 150 cause friction with the inner wall, and the inner wall is charged with the negative electrostatic charge. Phosphor micropowders are charged with a positive static charge.

In this way, the phosphor powder is previously charged with an electrostatic charge, so that the corona discharge electrode 144b of the coater generates a corona discharge only for a short time and a short time, thereby enabling charging necessary for development. As the corona is generated at such a low voltage, not only energy is saved, but the generation of free ions is drastically reduced, which does not disturb the phenomenon.

In addition, when the conductive film is formed on the outer wall of the triboelectric charge tube 150, as soon as it is charged, negative charges charged in the triboelectric charge tube 150 may be discharged through the conductive layer of the outer wall. Such conductive films may be applied with other conductive materials. Especially, it is preferable to contain 50 weight% or more of graphite especially. Accordingly, a large charge is not formed in the triboelectric charge tube 150, and the charged fine powders flowing therein also do not act as an electric attraction between the inner wall and the inner wall of the charged tube. It is not possible to form a positive amount of static charge large enough to cause a discharge. In addition, the electrical attraction is extremely fine, and only loses a positive static charge.

According to the configuration and operation according to the embodiment of the present invention as described above, it is possible to charge in advance with the triboelectric charge tube 150, and then to be charged only for a short time and a low voltage in the corona charging electrode 144b of the coater. In addition to saving energy, there is an effect such that the generation of free ions is rapidly reduced to not interfere with the phenomenon.

Claims (3)

A volatile conductive film and a volatile photoconductive film are formed on the inner surface of the panel, and the photovoltaic film is charged with electrostatic charge, and then the electrostatic charge is discharged from selected areas of the photoconductive film. A developer for manufacturing a dry electrophotographic screen for a cathode ray tube, comprising the steps of attaching charged fine powder particles to a region and fixing the fine powder particles attached to the photoconductive film to the photoconductive film, the hopper 148. A phosphor supply pipe 150 for supplying the phosphor to the developing container 142 through the venturi tube 146 from the; A coater comprising a corona charging electrode 144b and a nozzle 144a for charging and injecting the phosphor powder at an end of the phosphor supply pipe 150 inside the developing container; And a triboelectric charging tube 150 which is installed in the middle of the phosphor supply pipe 150 and is charged with electrostatic charge to the phosphor powder by friction with the phosphor powder passing through the inside. Developing apparatus for manufacturing screens. The method of claim 1, wherein when the fluorescent powder is dry fluorescent particles coated with a polymethyl methacrylate primary film and a polyacrylamide secondary film so as to have charging characteristics, the material of the triboelectric charging tube 150 is polyethylene. A developing device for producing a dry electrophotographic screen of a cathode ray tube. According to claim 1 or 2, wherein the discharge of the charge to the triboelectric charge tube 150 is formed through the conductive film formed on the outer wall, the inner wall surface is spiraled to increase the contact area to increase the efficiency of triboelectric charge A developing device for manufacturing a dry electrophotographic screen of a cathode ray tube, characterized in that the structure.