Shadow mask for cathode ray tube

A cathode ray tube comprising:

• a panel having a phosphor film on the inner surface thereof;
• a funnel connected to said panel;
• a neck connected to said funnel;
• an electron gun mounted within the neck to emit electron beams;
• a deflection yoke mounted around the outer circumference of said funnel to deflect the electron beams emitted from said electron gun;
• and
• a shadow mask mounted within said panel to color-selectively pass the electron beams emitted from said electron gun,
• with said shadow mask being formed with a curved surface comprising a radius of curvature corresponding to a perpendicular axis which passes through the center of said shadow mask decreases monotonely along the perpendicular axis from the center of said shadow mask and a radius of curvature corresponding to a parallel axis which passes through the center of said shadow mask decreases monotonely along the parallel axis from the center of said shadow mask,
• and the curved surface satisfies the following condition:
• [0.1RVmin+0.9RVmax, 0.9RVmin+0.1RVmax]⊂[RHmin, RHmax]
• wherein RVmin and RVmax respectively represent the minimum and the maximum value of the minimum radius of curvature corresponding to the perpendicular axis, and RHmin and RHmax respectively represent the minimum and the maximum value of the minimum radius of curvature corresponding to the parallel axis.