Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
  • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
  • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
  • H01J29/18—Luminescent screens
  • H01J29/187—Luminescent screens screens with more than one luminescent material (as mixtures for the treatment of the screens)
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
  • H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
  • H01J9/22—Applying luminescent coatings
  • H01J9/227—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
  • H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
  • H01J9/22—Applying luminescent coatings
  • H01J9/227—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines
  • H01J9/2271—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines by photographic processes

Definitions

• the invention relates to a method of manufacturing screens for cathode-ray tubes for reproducing color images comprising a luminescent layer containing at least two substances provided in discrete surfaces which luminesce in different colors upon excitation by electrons. More particularly the invention relates to a method of wetting and coating such a luminescent layer with a solution of an organic substance which forms a film after drying. Thereafter, a metal layer pervious to electrons is applied to this film. A substance which provides an index signal upon electron excitation then is applied to given areas with the aid of a photosensitive binder.
• the luminescent layer In such a cathode-ray tube, the luminescent layer generally contains three substances luminescing in different colors, green, red and blue. These substances are provided in form of strips between which are interposed strips consisting of a non-luminescent substance which is impervious to light. The substance providing an index signal upon electron excitation is furnished in the form of strips which occupy a given position with respect to the strips of the luminescent layer.
• the index signal may be obtained in different ways.
• the substance consists of secondary-emission material
• electron excitation results in an electron current which then is collected on a collector electrode.
• the substance has the property that upon electron excitation it emits radiation, generally ultraviolet radiation, which is collected in a photocell.
• the signals obtained in this manner are used for the co ordination of the instantaneous modulation of the electron beam, and the spot on the screen struck by the electron beam.
• the electron pervious metal layer below which the organic film is provided is wetted without the formation of an uninterrupted liquid layer and a solution of the photosensitive binder is spread thereon.
• the solution then is dried and exposed at the given areas to the influence of hardening radiation to harden the binder. After removal of the non-exposed binder the screen is baked out.
• the substance supplying an index signal upon electron excitation may be applied in various ways.
• the solution of the photosensitive binder may contain this substance in the form of a suspension, This substance is then already present at the given areas after the exposure to the hardening radiation and at the other areas the substance is removed together with the non-exposed binder.
• the substance is not suspended in the solution of the photosensitive binder. Consequently, in this case only the layer of binder is exposed to the influence of hardening; radiation. At the irradiated areas, the binder becomes insoluble, but if at least the irradiation is not continued for an excessively long time, it remains slightly sticky.
• the substance may subsequently be applied in the form of a suspension, during which process it adheres to the slightly sticky annealed parts so that it is not washed away during the subsequent removal of the non-exposed binder; or, the substance may be applied in the form of a suspension after the non-exposed binder has been removed.
• the binder 'of the luminescent layer, the organic film and the binder of the substance supplying an index signal upon electron excitation are removed.
• the organic film is still present below the electron pervious metal layer which always contains small pores.
• the liquid penetrates through the po es into the organic film and, also, through this film into the luminescent layer. Gas bubbles then ascend which due to the fact that the metal layer is not covered with a noninterrupted liquid layer can escape through the pores in the metal layer so that they do not damage the metal layer.
• the organic film provides a sufficient strength for the metal layer so that the solution of the photosensitive binder does not adversely affect the metal layer during the applica ion and the following processes.
• a liquid which does not attack the organic film, preferably a liquid which can readily be mixed with the solvent of the photosensitive binder. It is advantageous to carry out the wetting process by means of spraying or atomization, during which processes fine drops are formed.
• an aqueous solution of polyvinylalcohol in which a bichromate, for example, ammonium bichromate, serving as a sensitizer may be used.
• a bichromate for example, ammonium bichromate
• water or a mixture of water and alcohol may be used, for example.
• a dried layer of the solution can be hardened by exposing it to a radiation having a wave length lying between 3600 A. and 5000 A., whereupon the binder is no longer soluble in water and alcohol.
• the luminescent layer which is composed of differently luminescing strips with the interposition of non-luminescent strips, is wetted with water.
• an organic film is formed using a solution of one or more methacrylates in toluene.
• An aluminum layer is deposited by evaporation thereon in vacuo. By means of an atomizer, the aluminum layer is wetted with water.
• an aqueous solution is applied which consists of polyvinyl alcohol containing as a sensitizer, ammonium bichromate, and in the form of a suspension, a cerium-activated calcium-aluminum silicate. After drying, given areas are exposed to radiation having a wave-length lying between 3600 A. and 5000 A.
• a luminescent screen for a cathode-ray tube for reproducing color images comprising the steps of applying to given areas of a transparent substrate a luminescent layer consisting of at least two substances luminescing in different colors upon excitation by electrons, wetting and coating said luminescent .4 layer with a solution of an organic substance, drying said organic substance, applying a metal layer pervious to electrons to said film, and forming over a portion at said metal layer a strip of a substance supplying an indexing signal upon excitation by electrons the steps of wetting the metal layer with an interrupted liquid layer so as to penetrate said metal layer and first organic film, applying a solution of photosensitive binder on said liquid layer, drying the solution and exposing the same at areas corresponding to the location of the indexing strip to the influence of hardening radiation, removing the unexposed binder, and baking out the screen.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
• Radiation-Therapy Devices (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=19792810

Family Applications (1)

Country Status (9)

Cited By (2)

Citations (2)

• 1965
  • 1965-04-01 NL NL6504104A patent/NL6504104A/xx unknown
• 1966
  • 1966-03-21 US US535725A patent/US3484240A/en not_active Expired - Lifetime
  • 1966-03-28 CH CH446966A patent/CH448163A/de unknown
  • 1966-03-29 DK DK163166AA patent/DK118900B/da unknown
  • 1966-03-29 GB GB13854/66A patent/GB1089506A/en not_active Expired
  • 1966-03-29 AT AT296066A patent/AT264610B/de active
  • 1966-03-29 DE DE19661462819 patent/DE1462819A1/de active Pending
  • 1966-03-30 BE BE678728D patent/BE678728A/xx unknown
  • 1966-03-30 ES ES0324900A patent/ES324900A1/es not_active Expired

Patent Citations (2)

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