CATHODE-RAY TUBE

PURPOSE:To reduce influence of magnetization of a shadow mask itself and prevent chromatic misconvergence by forming a magnetic shield layer around the holes in the shadow mask, wherein the shield layer is made of a material having a higher mag. permeability than material constituting the shadow mask. CONSTITUTION:A mag. shield layer 10 with higher mag. permeability than that of a shadow mask 4 is formed around the holes 6 bored therein. Even though the shadow mark 4 is magnetized, the intensity of mag. field in each hole 6 is weakened because the lines of mag. flux around the hole 6 concentrate in the mag. shield layer 10. Further, refraction of the mag. field between the shadow mask 4 and mag. shield layer 10 decreases the length of mag. field where the electron beam flies. This decreases deflection of the electron beam when it passes through the hole 6, which reduces influence of magnetization of the shadow mask itself 4, and misconvergence is thus precluded.