Matsushita Electric Industrial Co., Ltd.

Toshihiro Daimon

Yasufumi Wada

A color picture tube in which an electron gun emits three electron beams arranged in line, in which the diameter of the spot () 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 () 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.

Color picture tube

A vertical electrode plate having three openings formed in-line through which three electron beams pass respectively is provided only inside a focusing electrode out of the focusing electrode and a final accelerating electrode. A horizontal electrode plate that is substantially parallel to an in-line plane extending toward the focusing electrode is formed at least one of above and below openings at the bottom of a shielding cup, only inside the final accelerating electrode. By setting the height h of the horizontal electrode plate optimally, it is possible to correct a horizontally-elongated distortion of a spot shape in edge portions of a screen, caused by a self-convergence magnetic field of a deflecting device. In this manner, a color display tube that achieves an image display with a high resolution can be provided.

Growing community of inventors

Katano, Japan

Toshihiro Daimon