Abstract: A perforated curved-surface portion of a shadow mask in a color picture tube satisfies the following conditions. At an arbitrary point on an X-axis and a Y-axis, Rr is one radius of curvature of a main radius of curvature group, and R1 is the other radius of curvature of the main radius of curvature group. On the Y-axis, |Rr|<|R1| is satisfied at an arbitrary point in a range where the distance from a center is LY or less. On the X-axis, |Rr|>|R1| is satisfied at an arbitrary point in a range where the distance from the center is Lx/3 or less, and |Rr|<|R1| is satisfied at an arbitrary point in a range where the distance from the center is 3 Lx/4 to LX. This can enhance mask curved-surface strength without degrading resolution and color purity.

Abstract: Notches formed in a skirt portion of a shadow mask include a plurality of first notches formed at long side and short side skirt portions and respectively forming first tongue portions at substantially central portions of the respective long side and short side skirt portions, and second notches formed as pairs so as to sandwich respective corner portions of the skirt portion and respectively forming second tongue portions. At the respective corner portions of the skirt portion, assuming that a length from a peripheral edge of a mask surface to welding points of the respective second tongue portions is Lwd, and a length from the peripheral edge of the mask surface to a distal end of at least one second notch is Lcd, Lcd and Lwd have a relationship of Lcd≦Lwd≦2Lcd.

Abstract: Notches formed in a skirt portion of a shadow mask include a plurality of first notches formed at long side and short side skirt portions and respectively forming first tongue portions at substantially central portions of the respective long side and short side skirt portions, and second notches formed as pairs so as to sandwich respective corner portions of the skirt portion and respectively forming second tongue portions. At the respective corner portions of the skirt portion, assuming that a length from a peripheral edge of a mask surface to welding points of the respective second tongue portions is Lwd, and a length from the peripheral edge of the mask surface to a distal end of at least one second notch is Lcd, Lcd and Lwd have a relationship of Lcd≦Lwd≦2Lcd.

Abstract: A shadow mask has a rectangular mask body opposed to the phosphor screen of a panel, and a rectangular mask frame attached to a peripheral portion of the mask body, and is supported on the panel by three mask holders such that it can move relative to the panel. Each mask holder has a fixed portion fixed to the mask frame, an engagement portion engaged with side walls of the panel, and a slope portion connecting the fixed portion to the engagement portion with a distance interposed between them. The slope portion of each mask holder has a cross section smaller at its fixed-portion side than at its engagement-portion side, and also has a responsiveness to a displacement in the mask frame due to thermal expansion thereof. This responsiveness is higher at the fixed-portion side than at the engagement-portion side.