Abstract: The invention provides method for etching a metallic sheet. The method includes a first step of forming an anticorrosive pattern defining apertures on one surface of the metallic sheet and an anticorrosive pattern defining smaller apertures than said apertures on the other surface of said sheet; a second step of lightly etching said the other surface for removing an oxide film on the surface of the metal to expose the surface of the metal; a third step of spraying an etching solution on said one surface for etching said one surface to a predetermined depth; and a fourth step of simultaneously spraying an etching solution on both surfaces of said metallic sheet for forming apertures in said metallic sheet. The invention provides an apparatus for practicing this method. The invention is preferably applied for forming apertures by etching in a metallic sheet to provide a shadow mask of a color CRT.

Abstract: A method for etching a metallic sheet and apparatus thereof with a first step of forming an anticorrosive pattern defining apertures on one surface of the metallic sheet and an anticorrosive pattern defining smaller apertures than the apertures on the other surface of the sheet; a second step of lightly etching the other surface for removing an oxide film on the surface of the metal to expose the surface of the metal; a third step of spraying an etching solution on the one surface for etching the one surface to a predetermined depth; and a fourth step of simultaneously spraying an etching solution on both surfaces of the metallic sheet for forming apertures in the metallic sheet. The invention is preferably applied for forming apertures by etching in a metallic sheet to provide a shadow mask of a color CRT.