Color picture tube having shadow mask assembly

Abstract

A shadow mask assembly 1 includes a shadow mask 2 of invariable curvature and rotatable by a minimum required amount when the ambient temperature changes. The shadow mask assembly includes a shadow mask 2 having a number of electron beam apertures, a support frame 3 for holding the shadow mask 2, and mask springs 4 for holding the support frame 3 inside a panel of a color picture tube, wherein the shadow mask 2 is made of a metal material composed chiefly of invar, and the support frame 3 and the mask springs 4 are made of low-expansion stainless steel or metal material having a coefficient of thermal expansion of not larger than 1.19.times.10.sup.-5 such as stainless steel whose chromium content is 11% to 16% by weight. In the shadow mask assembly 1 using such metal materials, the curvature at the peripheral edges of the shadow mask 2 does not locally change during the fabrication. A color picture tube provided with the shadow mask assembly 1 does not suffer excessive angular displacement with a change in the ambient temperature.

Dependencies are inferred from the claim text.