Patent ID: 6630776
Filing Date: 2003-10-07
Classification: H01J

Abstract:
A color cathode ray tube comprising:an envelope including a substantially rectangular face panel, a funnel connected to the face panel, and a neck connected to the funnel; a phosphor screen formed on an inner surface of the face panel; an electron gun located in the neck and configured to emit electron beams toward the phosphor screen; a substantially rectangular shadow mask located opposite to the phosphor screen in the envelope and having a given coefficient of thermal expansion; and a substantially rectangular mask frame having a coefficient of thermal expansion different from that of the shadow mask and supporting a peripheral edge portion of the shadow mask, the face panel, shadow mask, and mask frame having a major axis extending at right angles to a tube axis and a minor axis extending at right angles to the tube axis and the major axis, the shadow mask including a substantially rectangular effective region formed having a number of electron beam passage apertures and opposed to the phosphor screen, and a substantially rectangular skirt portion provided around the effective region and extending in the direction of the tube axis, the skirt portion having a pair of long sides extending substantially parallel to the major axis and a pair of short sides extending substantially parallel to the minor axis, the long and short sides being welded to the inner surface of the mask frame, a width of the skirt portion in the direction of the tube axis being uniform throughout a circumference of the shadow mask, and a first distance being a distance from an extending end of the skirt portion on each long side to a weld spot, a second distance being a distance from an extending end of the skirt portion on each short side to a weld spot, and the first distance being longer than the second distance.