Thin film coating and method of marking.

摘要

A thin film interference filter comprising in order: a transparent substrate (2); a first substantially transparent dielectric layer (8); a first metal precoat layer (10); a partially reflective metal layer (12); a second metal precoat layer (14); and a second substantially transparent dielectric layer (16), characterised in that the first metal precoat layer comprises nickel and chromium or chromium nitride, and the second metal precoat layer comprises nickel and chromium nitride.