Matsushita Electric Industrial Co., Ltd.

Katsumi Mitsuda

Hiroo Terada

Susumu Tsujihara

Katsumi Adachi

Minoru Takeda

Katsuhiko Yamamoto

Taiichi Saeki

A color cathode ray tube comprises (i) a glass bulb comprising a substantially rectangular panel, on which phosphors of a plurality of colors are arranged, a funnel that is connected to a rear side of the panel, and a neck portion formed at a rear side of the funnel, in which an in-line electron gun for emitting an electron beam is arranged; (ii) a substantially rectangular shadow mask having a plurality of apertures that are arranged in correspondence with the phosphors on the panel; and (iii) a substantially rectangular mask frame having a wall portion that supports opposing skirt portions of the shadow mask. The surface of the shadow mask with the apertures is convex towards the panel. A central portion of the opposing skirt portion is convex in a direction of the tube axis on the side of the electron gun. Processing warps such as wrinkles in the skirt portions of the shadow mask are avoided, and a color cathode ray tube with good color rendition is obtained.

Color cathode ray tube and method for manufacturing a shadow mask for a color cathode ray tube

A system for compensating image contour by modulating a scanning velocity in accordance with a video signal is disclosed, in which a mean current dissipated in a driving power amplifier is detected to control a gain of an amplifier in a preceding stage for suppressing the increase of power dissipation in the power amplifier when a video signal having many noises is received. The preceding stage amplifier is provided with a saturation characteristic to enhance the effect of contour compensation at a small amplitude signal and eliminate over compensation of image contour at a large amplitude signal. The combination of the saturation characteristic and the gain control further enhances the effect of suppression of power dissipation.

Scanning velocity modulation system

Growing community of inventors

Hyogo, Japan

Katsumi Mitsuda