US3677757A - Method of making phosphor screen for color cathode ray tube - Google Patents

Method of making phosphor screen for color cathode ray tube Download PDF

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Publication number
US3677757A
US3677757A US48027A US3677757DA US3677757A US 3677757 A US3677757 A US 3677757A US 48027 A US48027 A US 48027A US 3677757D A US3677757D A US 3677757DA US 3677757 A US3677757 A US 3677757A
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United States
Prior art keywords
adhesive binder
photosensitive adhesive
cathode ray
layer
ray tube
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Expired - Lifetime
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US48027A
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English (en)
Inventor
Masahiro Nishizawa
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Nippon Columbia Co Ltd
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Nippon Columbia Co Ltd
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/004—Photosensitive materials
    • G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
    • G03F7/11—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having cover layers or intermediate layers, e.g. subbing layers
    • 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

  • a method of making a phosphor screen of a multicolor cathode ray tube which comprises the steps of coating the inner face of the faceplate of the cathode ray tube with a photosensitive adhesive binder depositing a positive photosensitive layer over the entire area of the coated photosensitive adhesive binder, drying the deposited photoresist, exposing the photoresist layer to irradiation by light through a mask having a predetermined pattern to expose the underlying photosensitive adhesive binder layer at predetermined areas, developing the exposed inner face of the faceplate to remove the photoresist layer from the photosensitive adhesive binder layer to expose it at those areas exposed to light, rinsing the developed inner face of the faceplate with water, and dusting phosphor of a desired color on the exposed areas of the photosensitive adhesive binder layer.
  • the photosensitive adhesive binder is insoluble in water and in a developer after being exposed to light and becomes sticky due to absorption of
  • This invention relates to a method of making a phosphor screen for multi-color cathode ray tubes.
  • a phosphor slurry comprising a predetermined color emissive phosphor dispersed in a photosensitive adhesive binder material composed of polyvinyl alcohol and ammonium dichromate is coated on the interior surface of the faceplate of a cathode ray tube and the coated surface is subjected to an exposure and a development process after being dried, thereby to fix the phosphor.
  • the above processes are carried out for each color to provide a phosphor screen having a determined pattern.
  • a photosensitive adhesive binder material is coated on the interior surface of the faceplate of the cathode ray tube and a phosphor is dusted on the coated surface while the binder material is still adhesive and then the coated surface is dried. Then it is subjected to an exposure and a development process, and this process is repeated for each color to provide a predetermined pattern on the inner surface of the faceplate.
  • both conventional methods involve coating the inner face of the faceplate with the photosensitive 3,677,757 Patented July 18, 1972 "tice adhesive binder or phosphor a plurality of times for each color and thus the coating processes for manufacturing the phosphor screen are complex and expensive.
  • the use of a large-grained phosphor is desirable for enhancement of the brightness of the phosphor but in the slurry method dispersion of the phosphor in the photosensitive adhesive binder imposes a limitation on the size of the phosphor particles that can be employed.
  • the slurry method uses ammonium dichromate in an appreciably large amount relative to polyvinyl alcohol (usually 40 to 60 parts by weight of ammonium dichromate with respect 1,000 parts by weight of polyvinyl alcohol), which raises deterioration of the phosphors by chromium ions.
  • This invention eliminates the aforementioned drawbacks experienced in the prior art and has for its object a method of making a multi-color phosphor screen for a color cathode ray tube which comprises the steps of coating the interior surface of the faceplate of the color cathode ray tube with a photosensitive adhesive binder which becomes insoluble in water and a developer and sticky by absorption of moisture after exposure, depositing on the coated photosensitive adhesive binder positive photoresist over its entire area to a thickness suicient to permit light to pass during the exposure process, exposing the positive photoresist layer and the photosensitive adhesive binder lying thereunder to irradiation by light at predetermined areas through a mask after drying the positive photoresist layer, developing the coated interior surface of the faceplate to selectively remove the photoresist layer from the photosensitive adhesive binder at those areas exposed to light, rinsing the coated surface with water to cause the exposed areas ofthe photosensitive adhesive binder to have suicient adhesion for phosphor and
  • FIGS. A to E are diagrammatic views of the steps involved in the manufacture of a phosphor screen in accordance with one example of this invention.
  • FIGS. A to E reference numeral 1 indicates a faceplate of, for example, a color cathode ray tube, the inner face of which is coated with a photosensitive adhesive binder 2 composed of, for example, polyvinyl alcohol and ammonium dichromate to form a photosensitive adhesive binder layer 3.
  • a photosensitive adhesive binder 2 composed of, for example, polyvinyl alcohol and ammonium dichromate to form a photosensitive adhesive binder layer 3.
  • the photosensitive adhesive binder 2 is rendered insoluble in water and a developer by exposure to light and adhesive enough by absorption of water to permit adhesion of phosphors thereto.
  • the photosensitive adhesive binder is of a type such that ammonium dichromate contained therein is reduced by light to produce ions Cri and the resulting ions Craf and polyvinyl alcohol are cross-linked together so they are insoluble in water and in the developer.
  • the unreacted polyvinyl alcohol is sticky. With conventional methods, the unreacted polyvinyl alcohol causes mixing of the colors and complete reaction of the polyvinyl alcohol causes an increase in the amount of remaining chromium ions which results in the reduction of the brightness of the phosphors.
  • the amount of ammonium dichromate added to the photosensitive adhesive binder is selected to be 1,420 to 3&5 of the usual one, and about 1.6 to 3.0 parts by weight of ammonium dichromate is added to 1,000 parts by weight of polyvinyl alcohol to cause complete reaction of chromium which gives the photosensitive adhesive *binder in above-mentioned desired properties.
  • the blending ratio of the materials is the usual one or exceed it and the time of exposure is shortened to control the aforementioned crosslinking reaction, thereby to give the photosensitive adhesive binder the properties mentioned above.
  • a positive photoresist layer 4 is deposited on the binder layer 3 as depicted in FIG. B.
  • the positive photoresist is of the type that it becomes soluble in a developer when exposed to light.
  • the photoresist may be type FHR-l00, FHR-700 (Trademarks) produced by Fuji Yakuhin Kogyo Kabushikikaisha.
  • the positive photoresist is coated on the binder layer 3 to a thickness of about l to 20 microns which permits the passage of light therethrough.
  • the coated inner face is exposed to irradiation by light through a mask P having a predetermined transparent pattern at those areas which will be ultimately occupied by a phosphor of a desired color, as shown in FIG. C.
  • the positive photoresist layer 4 is so thin that the underlying photosensitive adhesive binder layer 3 is adequately exposed to light.
  • the time of exposure becomes a little longer but the time of exposure in the process depicted in FIG. C can be shortened by exposing the entire area of the photosensitive adhesive binder layer 3 to light to incompletely harden it prior to the formation of the positive photoresist layer 4.
  • the coated inner face is subjected to a developing process using a positive photoresist developer (such as manufactured by Fuji Yakuhin Kogyo Kabushikikaisha) to selectively dissolve the positive photoresist layer 4 at those areas S exposed to light, thus exposing the photosensitive adhesive binder layer 3 underlying it, as depicted in FIG. D.
  • a positive photoresist developer such as manufactured by Fuji Yakuhin Kogyo Kabushikikaisha
  • the coated inner face is rinsed with water to wash away the developer remaining thereon, leaving void areas in the positive photoresist layer 4 to expose the underlaying photosensitive adhesive binder layer 3 at selected areas as indicated by 6 in FIG. D.
  • the exposed areas 6 of the photosensitive adhesive binder 2 absonb water and become adhesive and sticky.
  • a phosphor 7 of a desired color is dusted on the rinsed inner face over its entire area, by which the phosphor 7 gets mixed into the exposed photosensitive sticky adhesive binder layer 6 as shown in FIG. E.
  • the unexposed surface of the positive photoresist layer 4 is relatively smooth, so that the phosphor is blown off by the air pressure during spraying and does not adhere to the surface of the positive photoresist layer 4.
  • this invention requires that the photosensitive adhesive binder be coated only once and hence simplifies the manufacturing operation and, at the same time, the thickness of the phosphor layer can be easily changed by suitably selecting the amount of ammonium dichromate added to the polyvinyl alcohol to make up the photosensitive adhesive binder and the time of exposure. Further, the photosensitive adhesive binder layer is temporarily covered with the positive photoresist and this makes it possible to hold the stickiness of the photosensitive adhesive binder layer uniform after exposure.
  • this invention provides for enhanced resolution and ensures the avoidance of mixing of colors and further allows the use of large-grained phosphor to improve brightness.
  • a method of making a phosphor screen of a multicolor cathode ray tube comprising the steps of:
  • a method of making a phosphor screen of a multicolor cathode ray tube according to claim 1 comprising the steps of exposing the positive photoresist layer to irradiation by light through a second mask having a pattern to expose the photosensitive adhesive binder layer at second predetermined areas, developing the exposed inner face of the faceplate to remove the positive photoresist layer from the adhesive binder layer at said second predetermined areas, rinsing the inner face of said face- References Cited UNITED STATES PATENTS 3/1966 Johnston 96-36.2 1/1967 Spiers 96-36.2

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)
US48027A 1969-06-28 1970-06-22 Method of making phosphor screen for color cathode ray tube Expired - Lifetime US3677757A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP44051122A JPS4814498B1 (fr) 1969-06-28 1969-06-28

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US3677757A true US3677757A (en) 1972-07-18

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JP (1) JPS4814498B1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3986073A (en) * 1971-08-18 1976-10-12 U.S. Philips Corporation Luminescent screen of a color television tube
US4292394A (en) * 1978-11-13 1981-09-29 E. I. Du Pont De Nemours And Company Process for preparing multicolor toned images on a single photosensitive layer
US4376158A (en) * 1977-05-09 1983-03-08 Keuffel & Esser Company Color-proofing method
CN106640199A (zh) * 2017-03-03 2017-05-10 贵州大学 一种矿用防突水警报装置

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3986073A (en) * 1971-08-18 1976-10-12 U.S. Philips Corporation Luminescent screen of a color television tube
US4376158A (en) * 1977-05-09 1983-03-08 Keuffel & Esser Company Color-proofing method
US4292394A (en) * 1978-11-13 1981-09-29 E. I. Du Pont De Nemours And Company Process for preparing multicolor toned images on a single photosensitive layer
CN106640199A (zh) * 2017-03-03 2017-05-10 贵州大学 一种矿用防突水警报装置

Also Published As

Publication number Publication date
JPS4814498B1 (fr) 1973-05-08

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