US3889146A - Electron gun assemblies for use in colour picture tubes - Google Patents

Electron gun assemblies for use in colour picture tubes Download PDF

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Publication number
US3889146A
US3889146A US448548A US44854874A US3889146A US 3889146 A US3889146 A US 3889146A US 448548 A US448548 A US 448548A US 44854874 A US44854874 A US 44854874A US 3889146 A US3889146 A US 3889146A
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United States
Prior art keywords
grid
perforations
electron
grid electrode
electrodes
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Expired - Lifetime
Application number
US448548A
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English (en)
Inventor
Kihachiro Koizumi
Yukihiro Izumida
Yoshihiko Miyata
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Hitachi Ltd
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Hitachi Ltd
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Publication date
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    • 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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/48—Electron guns
    • H01J29/50—Electron guns two or more guns in a single vacuum space, e.g. for plural-ray tube
    • H01J29/506—Electron guns two or more guns in a single vacuum space, e.g. for plural-ray tube guns in delta or circular configuration

Definitions

  • This invention relates to an electron gun assembly for use in a colour picture tube and more particularly to an improved construction of the grid electrode of a delta type electron gun assembly.
  • first grid in front of the cathode electrode.
  • the first grid is provided with a small opening having a diameter of from 0.6 to 1 mm at the center and applied with a negative potential with respect to the cathode electrode.
  • a second grid in front of the first grid and a potential of from 200 to 400 volts is applied to the second grid for deriving out an electron beam from the cathode electrode.
  • a third grid is disposed in front of the second grid with one end of the third grid contained in the second grid and the other end opposed to a fourth grid.
  • a potential of from 4 to kilovolts is impressed upon the third grid whereas a potential of 20 to 27 kilovolts is impressed upon the fourth grid for focusing the electron beam on a shadow mask.
  • the ends of the second, third and fourth grids are provided with peripheral beads and these grids are secured to glass bead supports, which in turn are mounted on a glass plate for supporting the electron gun assembly.
  • Each of three electron guns is inclined about 1 with respect to the tube axis so that three electron beams emitted by the guns converge at one point of the shadow mask.
  • the diameter of the electron lens is decreased to 70% of that of a tube having electron lens so that it has been difficult to improve the LII a deflection angle of 90 and a neck diameter of 36mm,
  • Another object of this invention is to provide an improved electron gun assembly for use in a colour picture tube which can be readily assembled at high accuracies.
  • Still another object of this invention is to provide an improved electron gun assembly for use in a colour picture tube capable of reducing the spherical aberration of the electron lens and reducing the variations of the beam spot position on the fluorescent screen, of the raster shift and of the initial drift of the convergence.
  • a delta type electron gun assembly for use in a colour picture tube comprising cathode electrodes which are arranged in a regular triangular configuration, a hollow cylindrical grid electrode disposed to confront the cathode electrodes and extending substantially coaxially with the tube in the direction of travel of the electron beams emanated by the cathode electrodes, the grid electrode being provided with three electron beam transmission perforations through one end wall thereof. These electron beam transmission perforations are also arranged in a regular triangular configuration.
  • FIG. 1 is a side view, partly broken away, of a prior art delta type electron gun assembly
  • FIG. 2 is an end view of the electron gun assembly shown in FIG. 1',
  • FIG. 3 is a side view of one embodiment of the electron gun assembly constructed in accordance with this invention and utilized in a colour picture tube;
  • FIG. 4 is an end view of the electron gun assembly shown in FIG. 3'
  • FIG. 5 is a partial sectional view taken along a line VV in FIG. 4.
  • FIG. 6 is a partial sectional view taken along a line VIVI in FIG. 4.
  • each electron gun 3 comprises a cathode electrode 9, a first grid electrode 10, a second grid electrode 11', a third grid electrode 12', and a fourth grid electrode 13' which are mounted on a glass plate 16 by glass bead supports 15, respectively.
  • the ends of the second to fourth grid electrodes are provided with peripheral beads 14 for the purpose of preventing high voltage discharge.
  • an electron gun assembly for use in a colour picture tube having a deflection angle of 1 10 and a neck diameter of 29mm,
  • a preferred embodiment of the electron gun assembly of this invention shown in FIGS. 3 to 6 comprises three first grid electrodes 10 arranged in a delta, three second grid electrodes 11 also arranged in a delta and disposed in front of the first grid electrodes, and a third hollow grid electrode 12 having a cross-sectional configuration of a regular triangle.
  • Three axial projections 17 disposed on the apices of a regular triangle are formed on one end of the third grid electrode 12 to confront respective second grid electrodes 11.
  • Each projection 17 is provided with a central aperture for transmitting the electron beam.
  • Three perforations are formed through the end wall of the third grid electrode 12 which confronts the fourth grid electrode 13 at positions corresponding to the perforations of the projections 17.
  • the third grid electrode 12 is formed by bonding together two halves of semicircular metal plates.
  • the fourth grid electrode 13 is also a cylindrical body having a cross-sectional configuration of a regular triangle, and its end wall confronting the third grid electrode 12 is also provided with three perforations 21 corresponding to the three perforations 20 of the third grid electrode 12.
  • the convergence of the electron beams is accomplished by a displaced electron lens which is formed by outwardly displacing the perforations 21 provided for the fourth grid 13 by about 0.1 to 0.2 mm with respect to the perforations 20 provided for the third grid electrode 12, or by providing a suitable convergence yoke, not shown. As shown in FIG.
  • the spacing 1 between two adjoining perforations 20 provided for the third control grid electrode 12 is determined by the inwardly and axially extending curved portion 19 that defines the perforation 20 as can be noted from FIG. 6, so that it is possible to make larger the diameter D than the prior art construction in which bead 14 is formed on the outer periphery of the grid electrode 12'.
  • the improved construction of this invention it is possible to increase the ratio D/S beyond 1.45 thus decreasing the spherical aberration of the main electron lens. More over, as it is possible to design the third grid electrode as an integral construction having a large length, it is possible to improve the resolution by 20 to 30% over the prior art construction. Further, as the grid electrodes applied with the same potential are united into an integral structure, and since respective electron guns are arranged substantially coaxial with the tube axis it is possible to readily fabricate the electron gun assembly at higher accuracies. Improvement of the accuracy of the fabrication also decreases the variations of the position of the electron beam spot on the fluorescent screen, of the raster shift and of the initial drift of the convergence.
  • each of the third and fourth grid electrodes was shown as an integral structure, it is also possible to construct the other grid electrodes (that is the first and second grid electrodes) also as integral structures.
  • the electron gun assembly was shown as of a bipotential type, it should be understood that the invention is also applicable to the electron gun assembly of the unipotential type.
  • the configuration of the triangle may be different provided that the object of this invention can be accomplished.
  • a delta type electron gun assembly for use in a colour picture tube comprising cathode electrodes arranged in a regular triangular configuration, first grid electrodes disposed in front of said cathode electrodes respectively, second grid electrodes disposed in front of said first grid electrodes respectively, a third hollow cylindrical grid electrode disposed to confront said second grid electrodes and extending substantially coaxially with said tube in the direction of travel of the electron beams emitted by said cathode electrodes, said third grid electrode being provided with three electron beam transmission perforations through one end wall far from said cathode electrodes thereof, said three perforations being also arranged in a regular triangular configuration, a fourth cylindrical grid electrode dis posed in front of said third grid electrode, said fourth grid electrode being also provided with three electron beam transmission perforations arranged in a regular triangular configuration through a wall facing to said one end wall thereof, said third and fourth cylindrical grid electrodes comprising members for forming a main electron lens by applying different potential thereon, and means for supporting said cathode electrode

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  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
US448548A 1973-08-29 1974-03-06 Electron gun assemblies for use in colour picture tubes Expired - Lifetime US3889146A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP48096106A JPS5046263A (enrdf_load_html_response) 1973-08-29 1973-08-29

Publications (1)

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US3889146A true US3889146A (en) 1975-06-10

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US448548A Expired - Lifetime US3889146A (en) 1973-08-29 1974-03-06 Electron gun assemblies for use in colour picture tubes

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US (1) US3889146A (enrdf_load_html_response)
JP (1) JPS5046263A (enrdf_load_html_response)
DE (1) DE2412349A1 (enrdf_load_html_response)
FR (1) FR2242774B1 (enrdf_load_html_response)
GB (1) GB1454568A (enrdf_load_html_response)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4124810A (en) * 1977-06-06 1978-11-07 Rca Corporation Electron gun having a distributed electrostatic lens

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2690517A (en) * 1952-09-30 1954-09-28 Rca Corp Plural beam electron gun
US2726348A (en) * 1953-05-26 1955-12-06 Rca Corp Multiple beam gun
US2752520A (en) * 1953-06-25 1956-06-26 Rca Corp Tri-color kinescope
US3772554A (en) * 1972-01-14 1973-11-13 Rca Corp In-line electron gun

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2690517A (en) * 1952-09-30 1954-09-28 Rca Corp Plural beam electron gun
US2726348A (en) * 1953-05-26 1955-12-06 Rca Corp Multiple beam gun
US2752520A (en) * 1953-06-25 1956-06-26 Rca Corp Tri-color kinescope
US3772554A (en) * 1972-01-14 1973-11-13 Rca Corp In-line electron gun

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4124810A (en) * 1977-06-06 1978-11-07 Rca Corporation Electron gun having a distributed electrostatic lens

Also Published As

Publication number Publication date
DE2412349A1 (de) 1975-03-27
FR2242774A1 (enrdf_load_html_response) 1975-03-28
FR2242774B1 (enrdf_load_html_response) 1978-09-29
GB1454568A (en) 1976-11-03
JPS5046263A (enrdf_load_html_response) 1975-04-24

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