US2419177A - Cathode-ray tube coating - Google Patents

Cathode-ray tube coating Download PDF

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Publication number
US2419177A
US2419177A US567343A US56734344A US2419177A US 2419177 A US2419177 A US 2419177A US 567343 A US567343 A US 567343A US 56734344 A US56734344 A US 56734344A US 2419177 A US2419177 A US 2419177A
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cathode
light
ray tube
tube
coating
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US567343A
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Steadman Albert
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Allen B du Mont Laboratories Inc
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Allen B du Mont Laboratories Inc
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/18Luminescent screens
    • H01J29/24Supports for luminescent material

Definitions

  • This invention relates to external coatings for cathode-ray tubes which improve the contrast of the trace of the beam on the face of the tube so that the apparent brightness is increased even in the presence of strong ambient or surrounding light.
  • a coating I of light-transmitting material is applied to the outside surface of the large end of a, cathode-ray tube 2.
  • the color of this coating I corresponds to the color emitted by the fluorescent or phos phorescent coating 3 on the inside of the tube 2.
  • This coating I adheres tenaciously to the outer face of glass tube 2 and will not be damaged by moisture, oil or grease.
  • such outside coating is made strong and tough enough to withstand abrasion effects which might be encountered during handling or use of the tubes upon the faces of which these coatings are applied.
  • Inert material in finely powdered form such as a divalent or trivalent metallic soap of the known sorts, is embodied in the coating I in amount sufficient to permit the desired degree of light transmission, while at the same time a suitable amount of specular diffusion of the transmitted light is caused to take place due to the presence of such 2 Claims.
  • a luminescent screen 3 of zinc orthosilicate is applied to the inner face of the large end of the cathode-ray tube 2 and the outer face of this tube is coated with inert material I described above. This material is tinted to a shade of green so that it passes light between 4750 angstroms and 5600 angstroms.
  • Such a film or layer transmits about lutions of natural or synthetic resin or combinaresponding as closely as possible to those of the fluorescent or phosphorescent luminosity of the screen material that is used.
  • Such coatings I are particularly useful when applied to fluorescent screened tubes that are used in television as receiving tubes.
  • the coating is tinted in accordance with the fluorescent luminosity of the screen material 3 that is used in such tubes.
  • a zinc sulphide-zine cadmium sulphide screen material 3 is used a preponderately white luminescence is produced so that a neutral gray tint is uite suitable for the coatin I that is used on the face of the tube 2 and has been found to be very effective since it has a practically uniform transmission characteristic over the entire range of the visible spectrum.
  • the light transmission through the coating material I has been found to be over of the fluorescent luminosity that is produced by bombarding the fluorescent screens of such tubes with cathode-rays or beams.
  • Th loss of light is not noticeable in the darkness, while the increase in contrast produces a considerable increase of apparent brightness when the pattern or trace on the fluorescent screen 3 is observed even in the presence of strong ambient light. Glare is also eliminated to a large extent or practically entirely and no apparent increase in the size of the light spot caused by the beam is noticeable.
  • the pattern or picture on the face of the tube can be observed in the usual way.
  • cathode-ray tubes can be used without employing shields to exclude ambient light from the faces of the tubes even in surroundings where there is high ambient light.
  • a cathode-ray tube having a screen and 3 having a layer or light-transmitting material on its face colored to correspond to the light produced by the cathode-ray beam of said tube on the screen thereof, said light-transmitting material having particles of inert material capable 5 of specular difl'ractlon distributed therein.
  • a cathode-ray tube having a screen and having a layer of light-transmitting material on its face colored to correspond to the light produced by the cathode-ray beam of said tube on the screen thereof, said light-transmitting material having particles of inert material distributed therein that produces specular diflusion 01' light.

Description

April 15, 1947. STEADMAN 2,419,177
CATHODE-RAY TUBE COATING Filed Dec. 9, 1944 HTTORNEY Patented Apr. 15, 1947 CATHODE-RAY TUBE COATING Albert Steadman, Upper Montclair, N. J., assignor to Allen B. Du Mont Laboratories, Inc., Passaic,-N. J., a corporation-of Delaware Application December 9,1944, Serial No. 567,343
This invention relates to external coatings for cathode-ray tubes which improve the contrast of the trace of the beam on the face of the tube so that the apparent brightness is increased even in the presence of strong ambient or surrounding light.
The invention may be understood from the following description in which a specific embodiment of the invention is described in connection with a somewhat diagrammatic drawing.
In carrying out the invention a coating I of light-transmitting material is applied to the outside surface of the large end of a, cathode-ray tube 2. The color of this coating I corresponds to the color emitted by the fluorescent or phos phorescent coating 3 on the inside of the tube 2. This coating I adheres tenaciously to the outer face of glass tube 2 and will not be damaged by moisture, oil or grease. At the same time such outside coating is made strong and tough enough to withstand abrasion effects which might be encountered during handling or use of the tubes upon the faces of which these coatings are applied. Inert material in finely powdered form, such as a divalent or trivalent metallic soap of the known sorts, is embodied in the coating I in amount sufficient to permit the desired degree of light transmission, while at the same time a suitable amount of specular diffusion of the transmitted light is caused to take place due to the presence of such 2 Claims. '(Cl. 250-164) A luminescent screen 3 of zinc orthosilicate is applied to the inner face of the large end of the cathode-ray tube 2 and the outer face of this tube is coated with inert material I described above. This material is tinted to a shade of green so that it passes light between 4750 angstroms and 5600 angstroms. Such a film or layer transmits about lutions of natural or synthetic resin or combinaresponding as closely as possible to those of the fluorescent or phosphorescent luminosity of the screen material that is used.
The following is given as a specific example of carrying out the invention, but the invention is not limited to this example.
82% of the fluorescent light that is produced by bombarding or scanning the screen 3 of the tube with a cathode-ray or beam. This loss of lighf is hardly noticeable in darkness, but the increase in contrast produces an increase of apparent brightness in the presence of strong ambient light. Glare is substantially or practically entirely eliminated and no change is noticed in the size of the spot that is caused by the cathoderay or beam. The coated face I of the tube 2 can be easily observed from any angle of observation within practical limits with respect to the plane of its surface.
Such coatings I are particularly useful when applied to fluorescent screened tubes that are used in television as receiving tubes. In all cases the coating is tinted in accordance with the fluorescent luminosity of the screen material 3 that is used in such tubes. For example, when a zinc sulphide-zine cadmium sulphide screen material 3 is used a preponderately white luminescence is produced so that a neutral gray tint is uite suitable for the coatin I that is used on the face of the tube 2 and has been found to be very effective since it has a practically uniform transmission characteristic over the entire range of the visible spectrum. The light transmission through the coating material I has been found to be over of the fluorescent luminosity that is produced by bombarding the fluorescent screens of such tubes with cathode-rays or beams. Th loss of light is not noticeable in the darkness, while the increase in contrast produces a considerable increase of apparent brightness when the pattern or trace on the fluorescent screen 3 is observed even in the presence of strong ambient light. Glare is also eliminated to a large extent or practically entirely and no apparent increase in the size of the light spot caused by the beam is noticeable. The pattern or picture on the face of the tube can be observed in the usual way.
With this invention cathode-ray tubes can be used without employing shields to exclude ambient light from the faces of the tubes even in surroundings where there is high ambient light.
What is claimed is: I l. A cathode-ray tube having a screen and 3 having a layer or light-transmitting material on its face colored to correspond to the light produced by the cathode-ray beam of said tube on the screen thereof, said light-transmitting material having particles of inert material capable 5 of specular difl'ractlon distributed therein.
2. A cathode-ray tube having a screen and having a layer of light-transmitting material on its face colored to correspond to the light produced by the cathode-ray beam of said tube on the screen thereof, said light-transmitting material having particles of inert material distributed therein that produces specular diflusion 01' light.
ALBERT STEADMAN.
REFERENCES crrnn The following references are of record in the file of this patent:
UNITED STATES PATENTS Date Number Name 2,124,225 Batchelor July 19, 1938 2,090,922 Von Ardenne Aug. 24, 1937 FOREIGN PATENTS Number Country Date 507,037 British Oct. 11, 1938 426,797 British Oct. 10, 1933 426,789 British Oct. 5, 1933
US567343A 1944-12-09 1944-12-09 Cathode-ray tube coating Expired - Lifetime US2419177A (en)

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2599739A (en) * 1950-04-12 1952-06-10 American Optical Corp Cathode-ray tube
US2612611A (en) * 1950-06-23 1952-09-30 Rauland Corp Cathode-ray tube
US2612612A (en) * 1950-06-23 1952-09-30 Rauland Corp Cathode-ray tube
US2680205A (en) * 1950-11-17 1954-06-01 American Optical Corp Cathode-ray tube and method of making same
US2690554A (en) * 1950-03-09 1954-09-28 American Optical Corp Ultraviolet filter for cathode-ray tubes
US2706262A (en) * 1950-07-15 1955-04-12 American Optical Corp Diffusion coated articles
US2734142A (en) * 1956-02-07 Cathode ray tubes
US2755413A (en) * 1951-02-23 1956-07-17 Edgar R Wagner Gas filled projector tubes for television
DE1005117B (en) * 1952-05-29 1957-03-28 Detag Attachment screen for television picture tubes
DE1008351B (en) * 1952-12-22 1957-05-16 Detag Attachment screen for television picture tubes
DE968937C (en) * 1951-06-06 1958-04-10 Siemens Elektrogeraete Gmbh According to the black-and-white method, television receiver with electron beam tube for image reproduction with a screen and with an optical filter arranged in front of it
DE1041526B (en) * 1952-05-27 1958-10-23 Siemens Elektrogeraete Gmbh TV receiver with electron beam tube for image reproduction
US3429997A (en) * 1965-06-09 1969-02-25 Rodenstock Optik G Image flattening optical system for electronic image converting tube
US3482088A (en) * 1967-01-30 1969-12-02 Hewlett Packard Co Solid state light source
US3814973A (en) * 1972-09-05 1974-06-04 Duro Test Corp Electric lamps of the vibrating filament type having a conductive coating

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB507037A (en) *
GB426789A (en) * 1933-07-06 1935-04-05 Siemens Reiniger Werke Ag Improvements in and relating to fluorescent screens
GB426797A (en) * 1933-09-05 1935-04-10 Siemens Reiniger Werke Ag Improvements in and relating to fluorescent screens
US2090922A (en) * 1932-11-21 1937-08-24 Ardenne Manfred Von Braun tube for producing television images rich in contrast
US2124225A (en) * 1935-02-14 1938-07-19 John C Batchelor Luminescent screen

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB507037A (en) *
US2090922A (en) * 1932-11-21 1937-08-24 Ardenne Manfred Von Braun tube for producing television images rich in contrast
GB426789A (en) * 1933-07-06 1935-04-05 Siemens Reiniger Werke Ag Improvements in and relating to fluorescent screens
GB426797A (en) * 1933-09-05 1935-04-10 Siemens Reiniger Werke Ag Improvements in and relating to fluorescent screens
US2124225A (en) * 1935-02-14 1938-07-19 John C Batchelor Luminescent screen

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2734142A (en) * 1956-02-07 Cathode ray tubes
US2690554A (en) * 1950-03-09 1954-09-28 American Optical Corp Ultraviolet filter for cathode-ray tubes
US2599739A (en) * 1950-04-12 1952-06-10 American Optical Corp Cathode-ray tube
US2612611A (en) * 1950-06-23 1952-09-30 Rauland Corp Cathode-ray tube
US2612612A (en) * 1950-06-23 1952-09-30 Rauland Corp Cathode-ray tube
US2706262A (en) * 1950-07-15 1955-04-12 American Optical Corp Diffusion coated articles
US2680205A (en) * 1950-11-17 1954-06-01 American Optical Corp Cathode-ray tube and method of making same
US2755413A (en) * 1951-02-23 1956-07-17 Edgar R Wagner Gas filled projector tubes for television
DE968937C (en) * 1951-06-06 1958-04-10 Siemens Elektrogeraete Gmbh According to the black-and-white method, television receiver with electron beam tube for image reproduction with a screen and with an optical filter arranged in front of it
DE1041526B (en) * 1952-05-27 1958-10-23 Siemens Elektrogeraete Gmbh TV receiver with electron beam tube for image reproduction
DE1005117B (en) * 1952-05-29 1957-03-28 Detag Attachment screen for television picture tubes
DE1008351B (en) * 1952-12-22 1957-05-16 Detag Attachment screen for television picture tubes
US3429997A (en) * 1965-06-09 1969-02-25 Rodenstock Optik G Image flattening optical system for electronic image converting tube
US3482088A (en) * 1967-01-30 1969-12-02 Hewlett Packard Co Solid state light source
US3814973A (en) * 1972-09-05 1974-06-04 Duro Test Corp Electric lamps of the vibrating filament type having a conductive coating

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