A method for einaetzung of perforations in a metal band, in particular for the manufacture of perforated masks for image bending of color television differential straight

摘要

A sheet of metallic material having a thickness T is covered on one side by an etchant resist and on the opposite side by an etchant resist and a removable shield. Etching is first performed on the side with only the etchant resist layer. Next, the shield is removed and the material is etched from both sides to produce an opening having a minimum dimension less than the thickness T of the material.