US3080231A - Process for photographically forming color screens - Google Patents

Process for photographically forming color screens Download PDF

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Publication number
US3080231A
US3080231A US387192A US38719253A US3080231A US 3080231 A US3080231 A US 3080231A US 387192 A US387192 A US 387192A US 38719253 A US38719253 A US 38719253A US 3080231 A US3080231 A US 3080231A
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US
United States
Prior art keywords
screen
phosphor
tube
phosphors
curved
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US387192A
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English (en)
Inventor
Lindsey R Perry
William E Rowe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CBS Broadcasting Inc
Original Assignee
Columbia Broadcasting System Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NL191673D priority Critical patent/NL191673A/xx
Application filed by Columbia Broadcasting System Inc filed Critical Columbia Broadcasting System Inc
Priority to US387192A priority patent/US3080231A/en
Priority to FR1113836D priority patent/FR1113836A/fr
Priority to GB30109/54A priority patent/GB758803A/en
Priority to DEC10120A priority patent/DE954336C/de
Application granted granted Critical
Publication of US3080231A publication Critical patent/US3080231A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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

  • This invention relates in general to color television and in particular to the preparation of luminescent screens for color television picture tubes.
  • the present invention consists in a photographic process for constructing color television picture tubes.
  • An example of the particular type of tube to which this process applies is disclosed in the co-pending application identified hereinabove.
  • Each of the required phosphors is settled through a waiter cushion on the screen surface of a tube according to well-known screen settling techniques.
  • a silica gel formed by activating a soluble silicate acts to bind the phosphor to the screen.
  • Settling screens through a water cushion is presently almost universally used by black-and-white picture tube manufacturers.
  • FIGURE is a block diagram indicating the process steps involved in preparing a color television picture tube screen in accordance with the present invention.
  • block 12 represents the first operation performed on the surface which is to form the screen of the picture tube.
  • This surface is the interior of the screen end of a conventional spherical or cylindrical face picture tube bulb, either round or rectangular, which has been cut on a plane perpendicular to the longitudinal axis of the bulb. The cut is made within a few inches of the screen itself, and a metallic flange is sealed to the cut surface. A similar flange is sealed to the other cut surface of the conical portion of the bulb.
  • the interior surface of the bowl-shaped screen end is thoroughly cleaned, as shown at 12. .At 13, a volume of deionized water sufiicient to cover the screen surface to a depth of about two inches is deposited in the screen end. At 14, a small amount :of precipitating agent is added to the Water cushion followed at 15 by the first phosphor charge which may be the green color-generating phosphor.
  • This phosphor charge consists of any one of several available compounds well known in the art for generating green light upon excitation, the phosphor being intimately mixed with a quantity of a soluble silicate solution.
  • the silicate solution upon meeting the previously added precipitating agent, forms a gel which entraps the phosphor particles as they settle resulting in the formation of a thin gel layer firmly bound to the screen surface.
  • the layer contains a uniform distribution of phosphor over the entire screen surface. The water through which the screen materials are settled is decanted after settling is complete.
  • Block 16 represents the step of adding any known water soluble photosensitive resist material as potassium dichromate.
  • the damp gel-phosphor layer is preferably sprayed to saturation with a suitable sensitizer, although the sensitizer may be floated on to saturate the phosphor layer if desired.
  • the screen end is baked at relatively low temperatures, resulting in the entire layer being hardened to a point where it becomes tightly adherent to the glass of the screen end of the tube. At this point, with the photo-sensitive resist material dry, it must be protected from bright light until the next process step is begun.
  • This next step, indicated by block 17, is the exposing of the sensitized layer.
  • the aperture mask which substantially conforms in shape to the screen surface and which is to be used in the tube itself is placed in the posi tion relative to the screen which it is to occupy in the finished tube.
  • a spot source of light is placed in a position which corresponds to the position to be occupied by the beam which will emanate from the electron gun to be used to energize the green color-generating phosphors.
  • the spot source is preferably of high intensity such as an argon arc.
  • the actual aperture mask to be used in the tube itself is the master pattern.
  • the phosphor layer itself is properly spaced from the mask.
  • the light beam from the spot source is oriented exactly as the electron beam from the green gun will be at the deflection center in the finished tube.
  • the optical analogy to the picture tube itself is complete and exposed areas on the screen layer are only those upon which the green beam will impinge in the finished tube.
  • the following step is the development of the screen layer to remove phosphor in unexposed areas. This is done as noted in block 18 by bathing the surface with deionized water to which a detergent has been added. The phosphor, silica gel and photosensitive resist material mixture, where it is not hardened by exposure, is thus removed. A light spray of deionized Water is then used to remove any traces of detergent, leaving the green dots bound to the screen surface. Finally, a gel hardening solution which may consist of a weak solution of formic acid in deionized water is used to further insure adhesion of the dots.
  • Block 19 indicates the settling, exposure, development, excess removal and fixing of the blue phosphor dots. This procedure is in every detail the same as that described above for the green phosphor dots except that the phosphor used is one of several commercially available for generating a blue light. Also, of course, the arc lamp is relocated to the position which corresponds to that of electron beams emanating from the blue gun in the finished tube. V
  • Deposition of the red phosphor dots, as in block 20, is another repetition of the entire process with similar exceptions that a commercially available red light-generating phosphor is used and the spot source of light is oriented such that its beam corresponds with the electron beam emanating from the red gun in the finished tube.
  • a final baking in air is given to the completed screen as indicated at block 21 to remove any residue of the photosensitive resist material and a light coating of a silicate solution is placed on the finished screen. This coating is dried and the screen is ready for aluminization. Subsequently, the aperture mask is inserted, the flanges are welded, guns are sealed in the tube neck and the completed tube is evacuated in a conventional manner, as indicated at block 22.
  • a process for forming a luminescent screen in a color television picture tube of the curved screen-curved mask type, said curved mask having a plurality of circular apertures symmetrically formed in substantially its entire surface comprising the steps of settling phosphors through a liquid cushion on to the interior surface of the screen end of said tube, permeating a water soluble photosensitive resist material through said phosphors, exposing predetermined portions of the areas of said photosensitive resist material and of said phosphors to light through said curved mask, and developing and washing away unexposed areas of said photosensitive resist material and of said phosphors from said screen surface.
  • -A process for forming a luminescent screen in a color television picture tube of the type having a curved viewing end, a curved aperture mask conforming to said viewing end, and at least a source of electrons comprising the steps of settling a phosphor layer through a liquid cushion on said viewing end, saturating said phosphor layer with photosensitive resist material, exposing said sensitized phosphor layer to light from a spot source of light to form discrete hardened areas of said sensitized layer corresponding in number and shape to the apertures in said aperture mask, developing away unhardened areas of said sensitized phosphor layer, baking said viewing end to remove residues of said photosensitive material, and disposing said sensitized source of electrons in a position previously occupied by said point source of light, where n said photosensitive resist material is water soluble and water is used to develop away unexposed areas.
  • a process for forming a luminescent screen on the inner surface of the viewing and of a color television picture tube of the curved screen-curved mask type characterized by covering the inner surface of the viewing end with deionized water to form a cushion thereon, adding a predetermined amount of a precipitating agent for a soluble silicate to the cushion, adding a mixture of particles of a phosphor material and an aqueous solution of a soluble silicate to the cushion, settling the gel resulting from the reaction of the precipitating agent and the soluble silicate to entrap the phosphor particles and to form on the inner surface of the viewing end a thin gel layer having a uniform distribution of the particles of phosphor therein, decanting the water cushion leaving the damp gel-phosphor layer, permeating the damp gel-phosphor layer with a water sensitive photosensitive resist material to form a gel-phosphor-resist layer, mounting a curved shadow mask behind the screen in the relation which it is to have in the finished tube, exposing discrete areas of the gel

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
US387192A 1953-10-20 1953-10-20 Process for photographically forming color screens Expired - Lifetime US3080231A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL191673D NL191673A (enrdf_load_stackoverflow) 1953-10-20
US387192A US3080231A (en) 1953-10-20 1953-10-20 Process for photographically forming color screens
FR1113836D FR1113836A (fr) 1953-10-20 1954-10-19 Perfectionnements relatifs à un procédé pour la fabrication d'écrans luminescents pour tubes récepteurs de télévision en couleurs
GB30109/54A GB758803A (en) 1953-10-20 1954-10-19 Process for forming colour screens
DEC10120A DE954336C (de) 1953-10-20 1954-10-20 Verfahren zum Herstellen von Leuchtschirmen fuer die Bildroehren des farbigen Fernsehens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US387192A US3080231A (en) 1953-10-20 1953-10-20 Process for photographically forming color screens

Publications (1)

Publication Number Publication Date
US3080231A true US3080231A (en) 1963-03-05

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Family Applications (1)

Application Number Title Priority Date Filing Date
US387192A Expired - Lifetime US3080231A (en) 1953-10-20 1953-10-20 Process for photographically forming color screens

Country Status (5)

Country Link
US (1) US3080231A (enrdf_load_stackoverflow)
DE (1) DE954336C (enrdf_load_stackoverflow)
FR (1) FR1113836A (enrdf_load_stackoverflow)
GB (1) GB758803A (enrdf_load_stackoverflow)
NL (1) NL191673A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3226246A (en) * 1960-08-06 1965-12-28 Philips Corp Method of manufacturing display screens for cathode-ray tubes
US3282691A (en) * 1962-07-06 1966-11-01 Rca Corp Method of fabricating cathode ray tube screen
US3440077A (en) * 1966-08-08 1969-04-22 Sylvania Electric Prod Method of fabricating a color cathode ray tube screen

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3054672A (en) * 1957-01-14 1962-09-18 Philco Corp Method of manufacturing electrical apparatus
US3056300A (en) * 1957-03-15 1962-10-02 Gen Motors Corp Unbalance indicator

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2328292A (en) * 1941-12-19 1943-08-31 Rca Corp Method of depositing phosphor materials
US2435889A (en) * 1943-06-02 1948-02-10 Johnson Matthey Co Ltd Production of metallic designs on nonmetallic materials
US2446915A (en) * 1946-07-13 1948-08-10 Gen Motors Corp Photographic process of producing a printing image
US2625734A (en) * 1950-04-28 1953-01-20 Rca Corp Art of making color-kinescopes, etc.
US2684306A (en) * 1947-10-09 1954-07-20 Emi Ltd Production of fluorescent screens by settling materials from liquid suspepnsions

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2328292A (en) * 1941-12-19 1943-08-31 Rca Corp Method of depositing phosphor materials
US2435889A (en) * 1943-06-02 1948-02-10 Johnson Matthey Co Ltd Production of metallic designs on nonmetallic materials
US2446915A (en) * 1946-07-13 1948-08-10 Gen Motors Corp Photographic process of producing a printing image
US2684306A (en) * 1947-10-09 1954-07-20 Emi Ltd Production of fluorescent screens by settling materials from liquid suspepnsions
US2625734A (en) * 1950-04-28 1953-01-20 Rca Corp Art of making color-kinescopes, etc.

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3226246A (en) * 1960-08-06 1965-12-28 Philips Corp Method of manufacturing display screens for cathode-ray tubes
US3282691A (en) * 1962-07-06 1966-11-01 Rca Corp Method of fabricating cathode ray tube screen
US3440077A (en) * 1966-08-08 1969-04-22 Sylvania Electric Prod Method of fabricating a color cathode ray tube screen

Also Published As

Publication number Publication date
GB758803A (en) 1956-10-10
NL191673A (enrdf_load_stackoverflow)
FR1113836A (fr) 1956-04-04
DE954336C (de) 1956-12-13

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