Masque optique pour réaliser des objets par voie photomécanique

摘要

An optical mask is produced by vapour depositing chromium on to a transparent substrate such as glass, masking part of the chromium with an etch resistant mask and etching the exposed chromium. The etch resistant mask is applied by a photo-lithographic technique and the etchant may be fuming HCl or a solution of HCl or H2SO4. The etching may be initiated by scratching the exposed chromium or by adding zinc or nickel to the etchant. The glass is heated prior to deposition of the chromium which forms a layer 1000A thick.