EP0178857B1 - Canon à électrons - Google Patents

Canon à électrons Download PDF

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Publication number
EP0178857B1
EP0178857B1 EP85307284A EP85307284A EP0178857B1 EP 0178857 B1 EP0178857 B1 EP 0178857B1 EP 85307284 A EP85307284 A EP 85307284A EP 85307284 A EP85307284 A EP 85307284A EP 0178857 B1 EP0178857 B1 EP 0178857B1
Authority
EP
European Patent Office
Prior art keywords
screen
gun
apertures
electron gun
grid electrode
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
Application number
EP85307284A
Other languages
German (de)
English (en)
Other versions
EP0178857A2 (fr
EP0178857A3 (en
Inventor
Hsing-Yao Chen
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.)
RCA Licensing Corp
Original Assignee
RCA Licensing Corp
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
Application filed by RCA Licensing Corp filed Critical RCA Licensing Corp
Publication of EP0178857A2 publication Critical patent/EP0178857A2/fr
Publication of EP0178857A3 publication Critical patent/EP0178857A3/en
Application granted granted Critical
Publication of EP0178857B1 publication Critical patent/EP0178857B1/fr
Expired legal-status Critical Current

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Classifications

    • 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
    • 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
    • H01J29/503—Three or more guns, the axes of which lay in a common plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/48—Electron guns
    • H01J2229/4834—Electrical arrangements coupled to electrodes, e.g. potentials
    • H01J2229/4837—Electrical arrangements coupled to electrodes, e.g. potentials characterised by the potentials applied
    • H01J2229/4841—Dynamic potentials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/48—Electron guns
    • H01J2229/4844—Electron guns characterised by beam passing apertures or combinations
    • H01J2229/4848—Aperture shape as viewed along beam axis
    • H01J2229/4858—Aperture shape as viewed along beam axis parallelogram
    • H01J2229/4865—Aperture shape as viewed along beam axis parallelogram rectangle
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/48—Electron guns
    • H01J2229/4844—Electron guns characterised by beam passing apertures or combinations
    • H01J2229/4848—Aperture shape as viewed along beam axis
    • H01J2229/4872—Aperture shape as viewed along beam axis circular

Definitions

  • the present invention relates to an electron gun according to the preamble of the claim.
  • a gun is known from the Japanese Patent OPI NO. 57,84554 ("Suzuki').
  • An inline electron gun is designed to generate at least two and preferably three, electron beams in a common plane and to direct the beams along convergent paths to a small area spot on the screen.
  • the beams When the yoke's fringe fields extend into the region of the electron gun, as is usually the case, the beams may be deflected slightly off axis and into a more aberrated portion of an electron lens of the gun. The result is frequently a flare distortion of the electron beam spot which extends from the spot toward the center of the screen. This condition is particularly troublesome in tubes having self-converging yokes with a toroidal deflection coil, because of the relatively strong finge fields of toroidal type coils.
  • Self-converging yokes are designed to have nonuniform fields in order to increasingly diver- age the beams as the horizontal deflection angle increases. These nonuniform fields also cause vertical convergence of the electrons within each individual beam. Thus, the beam spots are vertically overconverged at points horizontally displaced from the center of the screen, causing a vertically extending flare both above and below the beam spot.
  • a two-part screen grid electrode comprising a first apertured plate having an elongated aperture extending through the first plate and a second plate having a circular aperture therethrough.
  • a structure is disclosed in U.S. Patent No. 4,319,163, issued to Chen on March 9, 1982.
  • the second plate is energized with a DC bias voltage
  • the first plate is energized with a DC bias voltage superimposed with a dynamic signal synchronized with the horizontal and/or vertical deflection signals.
  • One drawback of this design is that, unless the modulation voltage is very small, the brightness of the tube also is modulated by the dynamic voltage applied.
  • U.S. Patent No. 4,443,736, issured to Chen on April 17, 1984, discloses a screen grid electrode structure including three stacked apertured metal plates separated from each other by two electrically insulating members.
  • the two outside plates have three inline apertures and the center plate has at least one elongated aperture effectively extending at least to the outer edges of the two outer apertures of the outside plates.
  • the two outer plates are electrically connected to screen grid potential and a dynamic signal is superimposed on the DC voltage applied to it.
  • the outside plate adjacent to the control grid electrode helps to minimize the brightness modulation of the tube; however in the patented structure, a brightness variation within the range of 20 to 30 - percent occurs. In order to reduce the brightness modulation further, it is necessary to apply counter-modulation to the cathode.
  • the three plate structure also provides difficultly during the beading operation, because of the close spacing required between adjacent metal plates.
  • Japanese Patent 57,84554 discloses an inline electron gun according to the preamble of the claim, a voltage is applied across the two screen grid electrodes; however it is unclear whether or not any modulation is employed, also, no dimensions of the screen grid electrodes are given.
  • an electron gun that has a screen grid structure that is suitable for utilization with a dynamic voltage to reduce the problem of flare, and which is easier to fabricate but provides at least the same or better brightness modulation than prior art gun structures.
  • an inline electron gun for a cathode-ray tube includes means for applying a modulation voltage to the second member of the screen grid electrode means, and the first member has a thickness about four times the thickness of the second member, thereby shielding the control grid from said modulation voltage and reducing brightness modulation in the tube.
  • Figure 1 shows a color picture tube 8 having a glass envelope 10, comprising a rectangular faceplate panel or cap 12 and a tubular neck 14 connected by a rectangular funnel 16.
  • the panel 12 comprises a viewing faceplate 18 and a peripheral sidewall 20 which is sealed to the funnel 16.
  • a mosaic three-color phosphor screen 22 is carried by the inner surface of the faceplate 18.
  • the screen 22 is preferably a line screen with the phosphor lines extending substantially perpendicular to the high frequency raster line scan of the tube (i.e., normal to the plane of Figure 1).
  • a multiapertured color selection electrode or shadow mask 24 is removably mounted, by known means, in predetermined spaced relation to the screen 22.
  • An improved inline electron gun 26, shown schematically by dashed lines in Figure 1, is centrally mounted within the neck 14 to generate and direct three electron beams 28 along coplanar convergent paths through the mask 24 to the screen 22.
  • the tube of Figure 1 is designed to be used with an external magnetic deflection yoke, such as the yoke 30 schematically shown surrounding the neck 14 and funnel 16 in the neighborhood of their junction.
  • the yoke 30 When activated, the yoke 30 subjects the three beams 28 to vertical and horizontal magnetic fields which cause the beams to scan horizontally and vertically, respectively, in a rectangular raster over the screen 22.
  • the initial plane of deflection (at zero deflection) is shown by the line P-P in Figure 1 at about the middle of the yoke 30. Because of fringe fields, the zone of deflection of the tube extends axially, from the yoke 30 into the region of the gun 26.
  • a magnetic deflection yoke 30 is a saddle-toroid type (ST yoke), such as described in U.S. Patent No. 4,143,345, issured to Barkow on March 6, 1979.
  • the electron gun 26 may be of the three beam inline type similar to those described in the above-cited U.S. Patent Nos. 4,234,814, 4,319,163 and 4,443,736, or to the inline, extended focus lens type described in U.S. Patent No. 4,370,592, issued to Hughes on January 25, 1983.
  • These patents disclose modified versions of the electron gun described in U.S. Patent No. 3,772,554, issued to Hughes on November 13, 1973.
  • the gun comprises two glass support rods 32 on which the various electrodes are mounted. These electrodes include three equally spaced inline cathodes 34 (one for each beam, but only one of which is shown), a control grid electrode 36 (GI), an improved screen grid electrode means 38 (G2a, G2b), a first main focus lens electrode 40 (G3), and a second main focus lens electrode 42 (G4), spaced along the glass rods 32 in the order named.
  • GI control grid electrode 36
  • G2a, G2b improved screen grid electrode means 38
  • G3 first main focus lens electrode 40
  • G4 second main focus lens electrode 42
  • the main electrostatic focusing lens in the gun 26 is formed between the G3 electrode 40 and the G4 electrode 42.
  • the G3 electrode 40 is formed with two cup-shaped elements 44 and 46, the open ends of which are attached to each other.
  • the G3 electrode 40 is shown as a two-piece structure, it could be fabricated from any number of elements, including a single element of the same length.
  • the G4 electrode 42 also is formed by two cup-shaped elements, 48 and 50, attached together at their open ends.
  • the main focus lens is shown as being formed by two electrodes, it could be formed by three, four or more electrodes (in which case the voltages applied would be different than shown).
  • the portion of the electron gun 26 comprising the cathodes 34, the control grid electrode 36 and the screen grid electrode means 38 is known as the beam forming region of the gun.
  • the beam forming region generates electrons and forms them into beams having crossovers in the vicinity of the screen grid electrode means 38.
  • the main focus lens electrodes 40 and 42 comprise the beam focusing region of the gun.
  • the beam focusing region establishes an electrostatic focusing field for focusing the electron beams to image the crossovers on the screen.
  • a first embodiment of the improved screen grid electrode means 38 includes two spaced apart metal members G2a and G2b.
  • the first metal member G2a located adjacent to the control grid 36 (G1), comprises a substantially flat plate having a thicknes of about 0.51 mm (20 mils).
  • three substantially identical horizontally disposed slots 52 are formed in one major surface of the first member G2a.
  • the slots 52 are each about 0.71 mm (28 mils) high, 2.03 mm (80 mils) wide, and 0.25 mm (10 mils) deep.
  • a circular aperture 54 is formed within each of the slots 52 and extends through the first member G2a in line with the apertures in the control grid 36 (G1).
  • the three circular apertures 54 have a diameter of 0.635 mm (25 mils).
  • the first member G2a is spaced about 0.229 mm (9 mils) from the control grid 36 (G1).
  • the second metal member G2b has a thickness of about 0.13 mm (5 mils) and is spaced about 0.13 mm (5 mils) from the first member G2a.
  • the second member G2b has three circular apertures 56 therethrough which have a diameter of 0.635 mm (25 mils) and are aligned with the circular apertures 54 in the first member G2a.
  • the G2a first member has a DC bias voltage applied thereto to control beam cutoff.
  • the G2b second member has a vertical and horizontal deflection related composite dynamic signal superimposed on a DC voltage applied to it. This dynamic signal modulates the beam cross sectional shape according to the deflection, thereby compensating for the above-mentioned flare.
  • the dynamic signal applied to the G2b member, in combination with the horizontally disposed slots 52 in the G2a member, improve the corner brightness to compensate for the reduction in edge transmission loss caused by the shadow mask 24.
  • the dynamic modulation voltage electrically varies the asymmetric slot lens strength between the first member G2a and the second member G2b of the screen grid electrode means 38, and hence also improves corner resolution without reducing center resolution.
  • the first member G2a which has a thickness of about four times the second member G2b, shields the dynamic signal from the area of the control grid 36 (G1), so that brightness modulation or fluctuation is reduced to about 3 percent as compared with about 20 to 30 percent in the above-cited U.S Patent No. 4,443,736.
  • the low level of brightness modulation obtained in the present structure eliminates the need for counter-modulation of the cathode as required in some prior art electron gums utilizing a dynamic modulation voltage on the screen grid.
  • the present structure is economical in that it is compatible with standard electron gun fabrication processes.
  • the slots in the G2a member can be vertically disposed, in which case waveforms such as those shown in Figure 6 can be applied to the G2b member.
  • waveforms such as those shown in Figure 6 can be applied to the G2b member.
  • the corresponding points on the screen of the tube are shown in Figure 7.

Landscapes

  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)

Claims (1)

  1. Canon à électrons en ligne (26) à utiliser dans un tube à rayons cathodiques (8), ledit canon comprenant, dans l'ordre, trois cathodes en ligne (34), une grille de commande (36) ayant trois ouvertures en ligne, un moyen formant électrode de grille écran (38) comprenant des premier (G2a) et second (G2b) organes espacés en métal, et deux électrodes de lentille de focalisation principale (40, 42), le premier organe en métal ayant trois fentes rectangulaires allongées (52) formées dans une surface majeure de celui-ci et une ouverture circulaire (54) formée dans chacune desdites fentes et traversant ledit premier organe, les ouvertures circulaires faisant face à ladite électrode formant grille de commande et étant alignées avec les ouvertures et le second organe en métal ayant trois ouvertures circulaires (56) qui le traversent qui sont alignées avec les ouvertures dans ledit premier organe, caractérisé en ce que ledit canon comprend un moyen pour appliquer une tension de modulation audit second organe dudit moyen formant électrode de grille écran et ledit premier organe a une épaisseur qui est égale à peu près à quatre fois l'épaisseur dudit second orgaine, pour ainsi protéger ladite grille de commande de ladite tension de modulation et réduire la modulation de luminosité dans ledit tube.
EP85307284A 1984-10-19 1985-10-11 Canon à électrons Expired EP0178857B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US66260384A 1984-10-19 1984-10-19
US662603 1984-10-19

Publications (3)

Publication Number Publication Date
EP0178857A2 EP0178857A2 (fr) 1986-04-23
EP0178857A3 EP0178857A3 (en) 1986-08-20
EP0178857B1 true EP0178857B1 (fr) 1989-08-30

Family

ID=24658390

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85307284A Expired EP0178857B1 (fr) 1984-10-19 1985-10-11 Canon à électrons

Country Status (10)

Country Link
EP (1) EP0178857B1 (fr)
JP (1) JPS6199251A (fr)
KR (1) KR860003644A (fr)
CN (1) CN85107200A (fr)
BR (1) BR8505150A (fr)
CA (1) CA1237464A (fr)
CS (1) CS719485A2 (fr)
DD (1) DD238473A5 (fr)
DE (1) DE3572748D1 (fr)
IN (1) IN165574B (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4731563A (en) * 1986-09-29 1988-03-15 Rca Corporation Color display system
US5036258A (en) * 1989-08-11 1991-07-30 Zenith Electronics Corporation Color CRT system and process with dynamic quadrupole lens structure
US5043625A (en) * 1989-11-15 1991-08-27 Zenith Electronics Corporation Spherical aberration-corrected inline electron gun
GB2269267B (en) * 1991-03-05 1995-02-15 Secr Defence Focusing means for cathode ray tubes
GB9104649D0 (en) * 1991-03-05 1991-04-17 Secr Defence Focusing means for cathode ray tubes
US5350967A (en) * 1991-10-28 1994-09-27 Chunghwa Picture Tubes, Ltd. Inline electron gun with negative astigmatism beam forming and dynamic quadrupole main lens
JPH0755891Y2 (ja) * 1992-01-22 1995-12-25 株式会社ララ 猫用排泄物シーツ
CN104157534B (zh) * 2014-08-21 2016-07-13 中国科学院电子学研究所 用于无截获栅控电子枪装配的工装夹具及对栅方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5784554A (en) * 1980-11-13 1982-05-26 Matsushita Electronics Corp Cathode-ray tube device

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4319163A (en) * 1980-06-30 1982-03-09 Rca Corporation Electron gun with deflection-synchronized astigmatic screen grid means
GB2084394B (en) * 1980-07-30 1985-03-06 Matsushita Electronics Corp Cathode-ray tube driving apparatus
JPS57103244A (en) * 1980-12-17 1982-06-26 Toshiba Corp Electron gun for color picture tube
IT1151376B (it) * 1981-04-29 1986-12-17 Rca Corp Complesso di cannoni elettronici presentante una regione perfezionata per la formatura di un fascio elettronico,tubo a raggi catodici e ricevitore televisivo incorporante lo stesso
US4443736A (en) * 1981-09-23 1984-04-17 Rca Corporation Electron gun for dynamic beam shape modulation
JPS59157936A (ja) * 1983-02-24 1984-09-07 Mitsubishi Electric Corp インラインカラ−ブラウン管用電子銃

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5784554A (en) * 1980-11-13 1982-05-26 Matsushita Electronics Corp Cathode-ray tube device

Also Published As

Publication number Publication date
EP0178857A2 (fr) 1986-04-23
IN165574B (fr) 1989-11-18
CS719485A2 (en) 1989-11-14
KR860003644A (ko) 1986-05-28
CN85107200A (zh) 1986-07-23
EP0178857A3 (en) 1986-08-20
BR8505150A (pt) 1986-07-29
DE3572748D1 (en) 1989-10-05
CA1237464A (fr) 1988-05-31
JPS6199251A (ja) 1986-05-17
DD238473A5 (de) 1986-08-20

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