Method of coating a transparent substrate
AssigneeFlachglas Aktiengesellschaft
InventorsRolf Groth, Dieter Muller
Life of this patent
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Abstract
Optical filters, e.g. for reflecting infrared radiation while passing visible light radiation is made by applying to the silver reflective coating a protective coating of a metal oxide by magnetron cathode sputtering and only thereafter is the dereflective layer applied by magnetron cathode sputtering. The protective coating-oxygen partial pressure and coating rate are substantially less than the dereflective coating-oxygen partial pressure and coating rate. Apparently the protective coating prevents damage to the reflective coating.
Claims10
A method of coating a transparent substrate with a multilayer optical filter which comprises the steps of:
- (a). applying a reflective silver coating to said substrate;
- (b). thereafter applying a protective coating to said silver coating of a metal oxide by magnetron cathode sputtering at an S protective coating rate and in an S protective coating partial pressure;
- (c). thereafter applying by magnetron cathode sputtering a dereflective metal oxide coating at an E dereflective coating-oxygen partial pressure and at an E dereflective coating rate;
- and
- (d). controlling the coating rates during the application of said protective and dereflective coating so that the S partial pressure is less than the E partial pressure and the S coating rate is less than the E coating rate.
Dependencies are inferred from the claim text.