Verfahren zum AEtzen mechanisch flach gemachter Flaechen von Siliciumdioxid-Gegenstaenden zur Herstellung optisch ebener Oberflaechen

摘要

1,116,558. Etching. NORTH AMERICAN AVIATION Inc. 13 Aug., 1965 [5 Nov., 1964], No. 34835/65. Heading B6J. Silicon dioxide is etched with a mixture of hydrofluoric acid, phosphoric acid and a wetting agent which is preferably a halogenated hydrocarbon. Etching is carried out in a cylindrical sloping container 10 rotated by an electric motor and formed with a stud 13 and a flange 14. A quartz disc 17 to be etched is mounted in a ring member 15 which rests on the stud 13 and flange 14 so as to rotate while the container rotates.