Patent ID: 6707241
Filing Date: 2004-03-16
Classification: H01J

Abstract:
A color cathode-ray tube comprising:a panel having a phosphor screen on an inner surface of the panel; an electron gun located opposite the phosphor screen and configured to emit electron beams toward the phosphor screen; a shadow mask located opposite the phosphor screen and having a large number of electron beam passage apertures through which the electron beams pass; and a substantially rectangular mask frame supporting a peripheral portion of the shadow mask, the shadow mask including a substantially rectangular mask main surface having the electron beam passage apertures, and a skirt portion extending from a peripheral edge of the mask main surface in a direction substantially perpendicular to the mask main surface, the mask main surface having a major axis extending perpendicular to a tube axis, a minor axis extending perpendicular to the tube axis and the major axis, and a diagonal axis extending through the tube axis, the skirt portion having a pair of long side skirt portions positioned on both sides of the major axis, a pair of short side skirt portions positioned on both sides of the minor axis, and a plurality of notches extending from an extended edge of the skirt portion toward the peripheral edge of the mask main surface, the notches being formed in the long side skirt portions and the short side skirt portions, and including a plurality of first notches defining first tongue portions respectively at substantially central portions of the respective long side skirt portions and substantially central portions of the respective short side skirt portions, and second notches provided as pairs so as to sandwich respective corner portions of the skirt portion and defining second tongue portions respectively, the mask frame being disposed at the outside of the skirt portion and welded to the first and second tongue portions, and at the respective corner portions of the skirt portion, when a length from a peripheral edge of the mask surface to welding points of the second tongue portions is Lwd, and a length from the peripheral edge of the mask main surface to a distal end of at least one of the second notches is Lcd, Lcd and Lwd have the relationship of: Lcd&lE;Lwd&lE;2Lcd.