Glass bulb for a cathode ray and a method of producing the same

Abstract

A glass panel 3 for a glass tube for a cathode ray tube has a flat panel face portion 7 and a reduced thickness while maintaining a sufficient strength without increasing a difference of brightness, and with less shrinking deformation due to the cooling and solidification of the glass panel. Compressive stress layers 20, 21 having a thickness of t.sub.o /10 or more are formed in outer and inner surfaces of the face portion 7 of the glass panel 3 respectively. The relation of the wall thickness t.sub.d of the central portion of the face portion to the wall thickness t.sub.o of a portion near an edge portion on a diagonal line is 1.0.ltoreq.t.sub.d /t.sub.o .ltoreq.1.2. Compressive stress layers 22, 23 are formed in outer and inner surfaces of a skirt portion 6 wherein the compressive stress value of the face portion 7 is larger than the compressive stress value of the skirt portion, and the compressive stress value of the outer surface 20 of the face portion is larger than that of the inner surface 21.

Dependencies are inferred from the claim text.