| 摘要 |
PURPOSE:To improve the molding accuracy as well as to prevent any deformation and sucklike, by making the vicinity of the tip of a shadow mask side wall part thicker than other parts of the side wall part, while carrying out the specified die-molding in which a shadow mask is molded. CONSTITUTION:A shadow mask 2 formed in rectangular externals carrying an opening part provided with a lot of apertures is attached to a mask frame 7 and disposed at a specified interval toward a panel 1 having a phosphor screen inside. In addition, when the shadow mask 2 is molded, the thickness of a plate T adjacent to a tip 17 of its side wall part 6 is made larger than the thickness of a plate (t) of the side wall part other than the vicinity of the tip in order to cause frictional resistance to grow large and furthermore a clearance between a die and a punch is rendered so as to be determined by the thickness the plate T in close vicinity to the tip. As a result, the frictional resistance at an outer surface 18 of the side wall part is substantially very little so that a curved effective part 3 can be uniformly molded as well as deterioration in color purity can be obviated. |
