Color cathode ray tube

A color cathode ray tube comprising:

• an envelope including a face panel having a substantially rectangular effective portion with a substantially flat outer surface;
• a phosphor screen provided on the inner surface of the effective portion;
• an electron gun configured to emit electron beams to the phosphor screen;
• and
• a shadow mask located between the phosphor screen and the electron gun, the shadow mask including a mask body having a substantially rectangular effective surface opposed to the inner surface of the effective portion of the face panel and formed having a large number of electron beam passage apertures,
• the effective portion of the face panel and the effective surface of the mask body having a major axis perpendicular to a tube axis, a minor axis perpendicular to the tube axis and the major axis, and a diagonal axis perpendicular to the tube axis,
• sags of the inner surface of the effective portion of the face panel in the direction of the tube axis toward the electron gun at the ends of each axis with respect to the center of the inner surface of the effective portion;
• the distances from the center of the inner surface of the effective portion to the individual axis ends;
• Sags of the effective surface of the shadow body in the direction of the tube axis toward the electron gun at the ends of each axis with respect to the center of the effective surface;
• and the distances from the center of the effective surface of the mask body to the individual axis ends have relations:
• 0.020<Z/L<0.060, and
• 0.025<Z′/L′<0.090,
• where Z/L and Z′/L′ represent ZPD/LPD, ZPH/LPH, or ZPV/LPV and ZMD/LMD, ZMH/LMH, or ZMV/LMV, respectively,
• ZPD, ZPH, and ZPV representing sags of the inner surface of the effective portion at the diagonal-axis end, major-axis end, and minor-axis end, respectively, of the effective portion of the face panel with respect to the center of the inner surface of the effective portion,
• LPD, LPH, and LPV representing the distances from the center of the inner surface of the effective portion to the diagonal-axis end, major-axis end, and minor-axis end, respectively, of the effective portion,
• ZMD, ZMH, and ZMV representing sags at the diagonal-axis end, major-axis end, and minor-axis end, respectively, of the effective surface of the mask body with respect to the center of the effective surface, and
• LMD, LMH, and LMV representing the distances from the center of the effective surface of the mask body to the diagonal-axis end, major-axis end, and minor-axis end, respectively, of the effective surface.