US3841876A - Method for making a phosphor screen of a cathode-ray tube - Google Patents

Method for making a phosphor screen of a cathode-ray tube Download PDF

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Publication number
US3841876A
US3841876A US00371569A US37156973A US3841876A US 3841876 A US3841876 A US 3841876A US 00371569 A US00371569 A US 00371569A US 37156973 A US37156973 A US 37156973A US 3841876 A US3841876 A US 3841876A
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United States
Prior art keywords
shadow mask
photosensitive layer
light
cathode
layer
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Expired - Lifetime
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US00371569A
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English (en)
Inventor
T Takemoto
Y Tomita
I Ijichi
S Maeda
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Hitachi Ltd
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Hitachi Ltd
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    • 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
    • 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

Definitions

  • the present invention relates to a method for making a phosphor screen of a cathode-ray tube or more in particular to an improvement on the method for making a phosphor screen of a cathode-ray tube disclosed in French Pat. No. 7,143,315 corresponding to U.S. Patent Ser. No. 204,020, now U.S. Pat. No. 3,775,116, filed on Dec. 2, 1971.
  • light-exposed portions of a photosensitive layer are smaller in diameter than and in registration with the shadow mask openings, and the photosensitive layer lies on a transparent layer which is in turn formed on the shadow mask, thus constituting a shadow mask assembly to be used for forming phosphor dots smaller in diameter than the shadow mask openings on the inner surface of the cathode-ray tube.
  • the light-exposed portions of the photosensitive layer remain unremoved over the shadow mask. This results in the lack of concentricity and/or roundness of the phosphor dots formed, often causing a resulting phosphor dot screen on the inner surface of the panel to undergo the serious problem of uneveness.
  • the shadow mask is liable to be damaged by the presence of a bonding agent on the whole surface of the shadow mask.
  • An object of the present invention is to provide an improved method offorming a phosphor screen of a cathode-ray tube without the above-mentioned inconveniences.
  • FIG. I is a sectional viewv showing the essential parts of an unfinished shadow mask assembly used'in the method of the invention.
  • FIG. 2 is a diagram showing a sectional view of the manner in which the shadow mask assembly is mounted on the frame.
  • FIG. 3 is a sectional view showing the essential parts of the shadow mask assembly for explaining an embodiment of the present invention.
  • a method for making a phosphor screen of a cathoderay tube comprising the steps of providing a transparent layer on that surface of a shadow mask which faces the phosphor screen within the cathode-ray tube, the shadow mask being carried by a supporting frame, the transparent layer being capable of attenuating light passing therethrough, providing a photosensitive layer on the transparent layer, exposing the photosensitive layer to light through the shadow mask and transparent of the phosphor pattern, the shadow mask assembly is washed with a detergent solution to remove the light exposed portions of the photosensitive layer.
  • a shadow mask 1 with openings of a predetermined diameter to be finally mounted on a cathode-ray tube is prepared, and a photosensitive sheet 2 consisting of a photosensitive layer 2a and a transparent layer 2b constituting a base film for the photosensitive layer 2a is closely attached, without being wrinkled, onto that surface la of the shadow mask 1 which is to face a phosphor screen.
  • the photosensitive sheet 2 is fixed on the shadow mask 1 at those portions which do not contribute to the formation of the phosphor screen by means of a bonding agent 3b put on the frame as shown in FIG. 2 or on the side face 3a of the shadow mask 1 engaged with the frame 3 or on both of the frame and the side face.
  • the photosensitive layer 2a may consist of polyvinyl chloride, natural rubber, synthetic rubber or the like which loses viscosity by photopolymerization in the presence of light or may consist of polyvinyl-carbazole which is accompanied by a change in its charged condition in the presence of light.
  • the photosensitive sheet 2 is exposed to light with a high-pressure mercury lamp (not shown) through an opening 1c of the shadow mask 1 from the electron gun side lb of the shadow mask 1 as indicated by the arrow in FIG. 1.
  • the temperature may be within the range from the room temperature to 90C preferably40 C in order to increase the photosensitivity of the photosensitive layer. 60C is the most appropriate for the exposure.
  • Light transmitted through the opening 1c of the shadow mask 1 reaches the photosensitive layer 2a through the transparent layer 2b, while being attenuated due to absorption and scattering in the transparent layer 2b.
  • the light-exposed portion 4 of the photosensitive layer 2a in registration with the opening 1c of the shadow mask 1 is smaller in diameter than the opening of the shadow mask 1, as illustrated in FIG. 3.
  • Particles of an opaque material 5 such as carbon or graphite with the size of 20 60 millimicrons are sprayed uniformly over the photosensitive layer 2a.
  • Those of the particles on the light-exposed portions 4 are removed by the well-known method such as air blast or immersion in a solvent. Although the need of this process may seem to be eliminated by the laterdescribed process of washing, the removal of the particles as mentioned above is desirable to assure successful results of the washing process.
  • the lightexposed portions 4 are rendered light-transsible and a layer of the opaque material 5 is formed on the photosensitive layer 2a except on the light-exposed portions 4, thereby forming in the photosensitive sheet 21 a light-transmissible portion of a smaller diameter than the opening of the shadow mask 1.
  • the photosensitive sheet 21 should be washed with a detergent solution containing an anionic surfactant such as an alkali salt of higher fatty acid, alkyl sulfate, alkylaryl sulfonate, or sulfosuccinic acid ester so that the light-exposed portions are melted off thereby to clearly define the boundaries for the light-transmissible portion or to produce a well-shaped light-transmissible hole.
  • an anionic surfactant such as an alkali salt of higher fatty acid, alkyl sulfate, alkylaryl sulfonate, or sulfosuccinic acid ester
  • a photosensitive layer 2a consisting of viscous natural rubber and having a thickness of 1 micron is exposed to light from a mercury lamp off400 W located 30 cm away through shadow mask openings havinga diameter of'0.32 mm and through a transparent layer 2b having a thickness of 8 microns to form light-exposed portions in the photosensitive layer 2a, and then carbon particles of millimicrons are sprayed on the photosensitive layer 2a.
  • the photosensitive layer 2a is processed with an air blast in order to remove particles on the light-exposed portions no longer having viscosity and thenis washed by the immersion thereof in a 0.5 percent aqueous solution of sodium alkylbenzenesulfonate for 30minutes.
  • the photosensitive layer 2a may consist of such a material as polyvinyl carbazole so that electric charges in the light-exposed portions 4 are removed by exposure to light for the repulsion of the opaque material.
  • An exposure process to form a phosphor screen is followed through the shadow mask 11 having the photosensitive sheet 21 i. e., through the shadow mask assembly.
  • a panel for the cathoderay tube with phosphor dots smaller in diameter than the opening of the shadow mask is obtained much more easily than the conventional method employing postetching.
  • the photosensitive sheet 21 fixed at the side face of the frame 3 is easily removed to recover a desired shadow mask 1.
  • the present invention is easily applicable to a color cathode-ray tube of chromatron type.
  • the present invention has the advantages that no special measures are required to prevent partial corrosion of the shadow mask and to maintain the diameter of the opening thereof.
  • the process of washing the photosensitive layer with a detergent solution contributes to the clarification of the boundaries for improved dimensional accuracy for the light-transmissible holes in the photosensitive layer.
  • the method of the invention has the advantage of the case with which the phosphor screen is produced economically with very few substandard products.
  • said shadow mask being carried by a supporting frame,-
  • said transparent layer being capable of attenuating light passing therethrough, providing a photosensitive layer on said transparent layer said photosensitive layer upon exposure to light being removable by washing with a detergentlsolution, exposing said photosensitive layer to light through said shadow mask and transparent over a shadow'mask to make the size of the light- 1 layer to form light-exposed portions smaller in diameter than the shadow mask openings in said photosensitive layer, developing said photosensitive layer with a light absorbing material that adheres to the unexposed portions to form, in accordance with the shadow mask openings, a pattern of efiective light-transmissible holes in said photosensitive layer thereby obtaining a shadow mask assembly, and forming a pattern of phosphors using said shadow mask assembly, the improvement comprising the fact that prior to the formation of the phosphor pattern, said shadow mask assembly is washed with a detergent solution to remove said lightexposed portions of said photosensitive layer.
  • said an ionic surfactant is selected from the group consisting of alkalisalt of higher fatty acid, alkyl sulfate, alkylaryl sulfonate, alkyl sulfonate and sulfosuccinic acid ester.
  • said photosensitive layer includes a material capable of photopolymerization and said exposing step is carried out at a temperature within a range from room temperature to C.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
US00371569A 1972-06-30 1973-06-19 Method for making a phosphor screen of a cathode-ray tube Expired - Lifetime US3841876A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47065000A JPS4924573A (de) 1972-06-30 1972-06-30

Publications (1)

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US3841876A true US3841876A (en) 1974-10-15

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US00371569A Expired - Lifetime US3841876A (en) 1972-06-30 1973-06-19 Method for making a phosphor screen of a cathode-ray tube

Country Status (5)

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US (1) US3841876A (de)
JP (1) JPS4924573A (de)
DE (1) DE2332724A1 (de)
FR (1) FR2191247B1 (de)
IT (1) IT986618B (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4533610A (en) * 1983-06-24 1985-08-06 Videocolor Method of manufacture of a color television tube having low screen reflectance for ambient light
US4980271A (en) * 1985-08-05 1990-12-25 Hoechst Celanese Corporation Developer compositions for lithographic printing plates with benzyl alcohol, potassium toluene sulfonate and sodium (xylene or cumene) sulfonate
US5066568A (en) * 1985-08-05 1991-11-19 Hoehst Celanese Corporation Method of developing negative working photographic elements
WO1998010461A1 (en) * 1996-09-04 1998-03-12 Saes Getters S.P.A. Thin-film phosphors for field emission displays

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2577675B (en) 2018-08-20 2023-07-05 Iq Structures Sro Gramophone plate with recorded image

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2961314A (en) * 1955-06-24 1960-11-22 Zenith Radio Corp Method of manufacturing color image reproducer
US3070441A (en) * 1958-02-27 1962-12-25 Rca Corp Art of manufacturing cathode-ray tubes of the focus-mask variety
US3653901A (en) * 1969-10-31 1972-04-04 Rca Corp Color kinescope production with a temporary mask
US3725065A (en) * 1970-09-30 1973-04-03 Rca Corp Method for making a kinescope comprising a color selection mask with temporary corridors
US3775116A (en) * 1970-12-04 1973-11-27 Hitachi Ltd Method for making a phosphor screen of a cathode-ray tube

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2961314A (en) * 1955-06-24 1960-11-22 Zenith Radio Corp Method of manufacturing color image reproducer
US3070441A (en) * 1958-02-27 1962-12-25 Rca Corp Art of manufacturing cathode-ray tubes of the focus-mask variety
US3653901A (en) * 1969-10-31 1972-04-04 Rca Corp Color kinescope production with a temporary mask
US3725065A (en) * 1970-09-30 1973-04-03 Rca Corp Method for making a kinescope comprising a color selection mask with temporary corridors
US3775116A (en) * 1970-12-04 1973-11-27 Hitachi Ltd Method for making a phosphor screen of a cathode-ray tube

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4533610A (en) * 1983-06-24 1985-08-06 Videocolor Method of manufacture of a color television tube having low screen reflectance for ambient light
US4980271A (en) * 1985-08-05 1990-12-25 Hoechst Celanese Corporation Developer compositions for lithographic printing plates with benzyl alcohol, potassium toluene sulfonate and sodium (xylene or cumene) sulfonate
US5066568A (en) * 1985-08-05 1991-11-19 Hoehst Celanese Corporation Method of developing negative working photographic elements
WO1998010461A1 (en) * 1996-09-04 1998-03-12 Saes Getters S.P.A. Thin-film phosphors for field emission displays

Also Published As

Publication number Publication date
IT986618B (it) 1975-01-30
DE2332724A1 (de) 1974-01-17
FR2191247B1 (de) 1976-05-28
FR2191247A1 (de) 1974-02-01
JPS4924573A (de) 1974-03-05

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