US 6,400,105 B2Granted

Color cathode-ray tube having electrostatic quadrupole lens exhibiting different intensities for electron beams

AssigneeHitachi, Ltd.

InventorsGo Uchida, Syoji Shirai, Shinichi Kato, Masafumi Nagaoka

Life of this patent

Estimating the term…

Loading patent…

Abstract

A focus electrode is constituted by a first type of focus electrode group to which a first focus voltage is applied, and a second type of focus electrode group to which a second focus voltage is applied. Between the first type of focus electrode group and the second type of focus electrode group are formed a lens at least having a lens action for correcting the field curvature and an electrostatic quadrupole lens. The center axes of the outer electron beam passage holes in the first type of focus electrode forming the lens at least having a lens action for correcting the field curvature are deviated on a horizontal plane from the center axes of the outer electron beam passage holes in the second type of focus electrode. The electrostatic quadrupole lens produces dissimilar intensities for the outer electron beams and for the center electron beam. Therefore, the outer electron beam passage holes work to deflect the outer electron beams toward the center electron beam with an increase in the deflecting amount of the electron beams, and a favorable resolution is obtained on the whole screen of the cathode-ray tube.

Claims19

Dependent claims

A color cathode-ray tube comprising at least a panel portion having a phosphor screen on an inner surface thereof, a neck portion, a funnel portion connecting said panel portion and said neck portion, an in-line type electron gun housed in said neck portion, and a deflection yoke for scanning electron beams on the phosphor screen;

wherein said electron gun has a cathode, a control electrode, an accelerating electrode and a main lens section disposed in the recited order in a direction toward said phosphor screen:
said main lens section comprising an anode to which an anode voltage is applied, and a focus electrode,
said focus electrode having a first type of focus electrode group to which a first focus voltage is applied, and a second type of focus electrode group to which a second focus voltage is applied;
said second focus voltage is obtained by superposing a voltage, that changes depending upon the deflecting amount of the electron beams, on a predetermined voltage;
between the first type of focus electrode group and the second type of focus electrode group are formed at least two electron lenses including a lens for correcting the field curvature for focusing the electron beams in both the horizontal direction and the vertical direction, and an electrostatic quadrupole lens for focusing said electron beams in either the horizontal direction or the vertical direction and for diverging the electron beams in the other of said directions;
three electron beam passage holes are formed in the electrodes that form said lens for correcting the field curvature, and the centers of the outer electron beam passage holes in the first type of focus electrode group are deviated relative to the centers of the outer electron beam passage holes in the second type of focus electrode group in the horizontal direction;
and
said electrostatic quadrupole lens exhibits different intensities for the outer electron beams relative to the center electron beam.

5 more elements

wherein said electron gun has a cathode, a control electrode, an accelerating electrode and a main lens section disposed in the recited order in a direction toward said phosphor screen:
said main lens section comprising an anode to which an anode voltage is applied, and a focus electrode;
said focus electrode having a first type of focus electrode group to which a first focus voltage is applied, and a second type of focus electrode group to which a second focus voltage is applied;
said second focus voltage is obtained by superposing a voltage, that changes depending upon the deflecting amount of the electron beams, on a predetermined voltage;
between the first type of focus electrode group and the second type of focus electrode group are formed at least two electron lenses including a lens at least having a lens action for correcting the field curvature for focusing the electron beams in both the horizontal direction and the vertical direction, and an electrostatic quadrupole lens for focusing said electron beams in either the horizontal direction or the vertical direction and for diverging the electron beams in the other of said directions;
three electron beam passage holes are formed in the electrodes that form said lens at least having a lens action for correcting the field curvature, and the horizontal diameter of the outer electron beam passage holes in the first type of focus electrode is larger than the horizontal diameter of the outer electron beam passage holes in the second type of focus electrode;
and
said electrostatic quadrupole lens exhibits different intensities for the outer electron beams relative to the center electron beam.

5 more elements

wherein said electron gun has a cathode, a control electrode, an accelerating electrode and a main lens section disposed in the recited order in a direction toward said phosphor screen:
said main lens section comprising an anode to which an anode voltage is applied, and a focus electrode;
said focus electrode having first type of focus electrode group to which a first focus voltage is applied, and a second type of focus electrode group to which a second focus voltage is applied;
said second focus voltage is obtained by superposing a voltage, that changes depending upon the deflecting amount of the electron beams, on a predetermined voltage;
between the first type of focus electrode group and the second type of focus electrode group are formed at least two electron lenses including a lens at least having a lens action for correcting the field curvature for focusing the electron beams in both the horizontal direction and the vertical direction, and an electrostatic quadrupole lens for focusing said electron beams in either the horizontal direction or the vertical direction and for diverging the electron beams in the other of said directions;
three electron beam passage holes are formed in the electrodes that form said lens at least having a lens action for correcting the field curvature, and the horizontal diameter of the outer electron beam passage holes in the first type of focus electrode is smaller than the horizontal diameter of the outer electron beam passage holes in the second type of focus electrode;
and
said electrostatic quadrupole lens exhibits different intensities for the outer electron beams relative to the center electron beam.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/066,756Filed 27 Apr 1998
Priority: JP 9-2411185 Sep 1997
Published: US 2001/0013760 A116 Aug 2001
Granted: 4 Jun 2002
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H01J 29/503
Two or more guns in a single vacuum space, e.g. for plural-ray tube: three or more guns, the axes of which lay in a common plane
H01J 2229/4841
Characterised by the potentials applied: dynamic potentials
H01J 2229/4879
Aperture shape as viewed along beam axis: non-symmetric about field scanning axis
H01J
Electric discharge tubes or discharge lamps