Superposed fine-detail multi-level patterns (e.g., superposed diffraction gratings having specified line spacing dimensions less than 10 micrometers and specified depth dimensions less than 5 micrometers) can be fabricated by linearly adding (e.g., by evaporation) an additional two-level pattern to an...http://www.google.es/patents/US4155627?utm_source=gb-gplus-sharePatente US4155627 - Color diffractive subtractive filter master recording comprising a plurality of superposed two-level relief patterns on the surface of a substrate
Color diffractive subtractive filter master recording comprising a plurality ...
