DIFF Subgroup
C03C 17/3411 Full Title
Surface treatment of glass, not in the form of fibres or filaments, by coating (optical coatings of optical elements G02B1/10) > with at least two coatings having different compositions (C03C17/44 takes precedence)
Of 3 combined children, 0 exist in both systems.
3 codes are CPC-only extensions.