Color picture tube
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsYasufumi Wada, Toshihiro Daimon
Life of this patent
Estimating the term…
Abstract
A color picture tube in which an electron gun emits three electron beams arranged in line, in which the diameter of the spot (26) at the center of the screen in the in-line direction is smaller than that in the direction perpendicular to the in-line direction when the spot is in a just-focused state. Therefore the shape of the spot (27) at the periphery of the screen is generally a true circle. As a result, the resolution at the periphery of the phosphor screen is improved, and the more is suppressed.
Claims5
(Amended) A color picture tube, with three electron beams arranged in an in-line manner being emitted from an electron gun,
- wherein a main lens portion formed in the electron gun comprises a main electrostatic lens that has a converging effect in the in-line direction and a direction perpendicular thereto and an electrostatic lens that is disposed at a stage immediately after the main electrostatic lens and has a converging effect in the in-line direction and a diverging effect in the direction perpendicular thereto, and
- when a spot formed in a central portion of a screen is just in focus, the spot in the central portion of the screen has a dimension along the in-line direction smaller than that along the direction perpendicular to the in-line direction.
(Amended) A color picture tube, with three electron beams arranged in an in-line manner being emitted from an electron gun,
- wherein an electron beam emitting region of a cathode in the electron gun has a dimension along the in-line direction smaller than that along the direction perpendicular to the in-line direction, and
- when a spot formed in a central portion of a screen is just in focus, the spot in the central portion of the screen has a dimension along the in-line direction smaller than that along the direction perpendicular to the in-line direction.
Dependencies are inferred from the claim text.