| 摘要 |
PURPOSE:To obtain a shadow mask formed uniformly a through-hole having a desired sectional shape by etching one surface of a thin metallic sheet to form a recess, subjecting the surface formed with such recess to protective coating and etching the other surface to penetrate the through-hole. CONSTITUTION:Resist films 4, 5 having hole-forming parts are formed on both main surfaces of the thin metallic sheet 1 consisting of a low carbon steel, etc. A protective film 7 is adhered to the large hole side of the top surface and an etching soln. 9 is sprayed to the small hole side on the bottom surface to form the recess 8. The film 5 is stripped after washing and the plate 1 is upset. An etching resistance layer 6 is formed on the surface including the recess 8. The film 7 is stripped and the etching soln. 9 is sprayed to the large hole side to form the large hole side recess down to the layer 6, by which the shadow mask aperture is obtd. The layer 6 and the film 4 are stripped after washing. The sheet is then passed again through etching and cutting stages, by which the intended flat mask is obtd. |
