Color picture tube having a face panel with an outer face having a hyperbolic curvature

摘要

In a color picture tube, curvature of outside face of said face panel is defined by <IMAGE> wherein Z is a distance in a direction of tube axis from an X-Y plane tangential at the center of the face, r is a distance from the center of the face panel to said point therealong, and A and B are constants of positive integers, respectively; thus the face panel excludes point of inflection and the reproduced picture thereon has a flat appearance, without trouble of undesirable doming of shadow mask.