Method for manufacturing a shadow mask
 A method for manufacturing a shadow mask is used for color television picture tubes and the like. The surface of a shadow mask body, made of Fe-Ni type alloy, is ion-nitriding processed so as to make the most of the low thermal expansion property inherent in the alloy. The result is that the color purity degradation caused by the thermal expansion at temperature increases of the mask, and by the resonance of the mask itself, can be prevented, thereby realizing a shadow mask serving to render a highly refined CRT. 
Mitsubishi Denki Kabushiki Kaisha
C H C C
C23C H01J C21D C23C
inventional inventional inventional inventional
Hideya Hiroyuki Kimio Tetsuya
Ito Teramoto Hashizume Watanabe