SHADOW MASK FORMING DIE

PURPOSE:To relax the holding of a shadow mask and to prevent the deformation of an electron beam passing hole, by changing the clearance between a blank holder and a die in a shadow mask forming stage. CONSTITUTION:A shadow mask forming die is constituted of a blank holder 18 made to prevent creases from generating in the circumference of a shadow mask, a punch 19 arranged freely slidably in the holder 18 and used for bulging a flat shadow mask into a curved surface, a die 22 for forming the shadow mask in correspondence with the holder 18, a pad 23 for holding and floating the die 22 and taking out a formed shadow mask 1, upper and lower stoppers 24, 25 for floating the holder 18 and maintaining the clearance between the holder 18 and the die 22 on the way of forming, and a die set 26 for fixing the lower stopper 25.