Treatment of ophthalmic glass for subsequent trimming operations comprises use of temporary protective coating of magnesium fluoride which is then chemically treated

摘要

The treatment of an ophthalmic glass, with two principal surfaces of which at least one incorporates an external organic or mineral layer coated with a temporary protective layer of MgF 2, comprises: (a) chemical treatment by a liquid of the temporary protective layer, leading to the formation of a layer of MgO on the temporary protective layer; (b) deposition of at least one metal oxide and/or at least one non-fluoride metal hydroxide on the temporary protective layer by transfer or from an electrostatic film or by evaporation under vacuum or directly on the temporary protective layer; and (c) the deposition of the temporary protective layer of MgF 2 on the external layer by evaporation under vacuum at a speed of less than or equal to 0.5 nm/second. An independent claim is included for an ophthalmic lens treated as above.