Multilayer coating for a polycarbonate substrate.

摘要

Multilayer coating for polycarbonate substrate used as a glass substitute, consisting essentially of silica, oxygen and nitrogen, and hydrogen according to the formula SiO2:H SiNy:H characterized by a composite structure of the coating combining an interferential system with a reflectance window extending over a narrow band of wavelengths from the lower edge of the visible region toward wavelengths shorter than ultraviolet on the one hand, and an absorptive system of which the band of wavelengths of transmission from the absorptive region to the transparent region is located in the reflectance window of the interferential system. There is thus provided a coating with an abrupt variation of coefficient of transmission. The multilayer coating is particularly useful as a glass substitute for automobile headlight lenses.