OPTICAL ARTICLE COMPRISING AN ANTI-REFLECTING COATING HAVING ANTI-FOGGING PROPERTIES

摘要

An optical article having anti-fogging properties, comprising a substrate having one main face coated with an anti-reflecting stack of layers of low refractive index (Ll) and high refractive index (HI) including an outermost and innermost layer, wherein the outermost layer of the anti-reflecting stack is a sandwich layer comprising a core portion interleaved between two side portions, said core portion being made of SiO2, SiOx with 1 =x2 and SiOx or a mixture of SiO2 and/or SiOx with 10% by weight or less, based on the total weight of the mixture, of AI2O3, having a physical thickness ranging from 20 to 150 nm, preferably 30 to 80 nm and being formed by vacuum evaporation deposition in a vacuum chamber at a deposition rate of at least 1.10 nm/s and/or maintaining a pressure higher than or equal to 1 x10-4 mbar, preferably ranging from 1.2 x 10-4 mbar to 5 x 10-4 mbar in said vacuum chamber during deposition by introducing inside said vacuum chamber at least one gas selected from the group consisting of oxygen, an inert gas or a mixture thereof, said gas pressure, the side portions being made of a material selected from the same materials as for the core portion, having a physical thickness of 1 to 50 nm, preferably from 2 to 20 nm and being formed by vacuum evaporation deposition at a deposition rate of less than 1.10 nm/s and maintaining a pressure ranging from 1 x10-5 mbar to less than 1 x 10-4 mbar, preferably 0.2 x 10-4 mbar 0.5 x10-4 mbar inside the vacuum chamber, optionally by introducing at least one gas selected from the same group as for the core portion, and, wherein the innermost layer is made of a material selected from the same group as for the core portion of the outermost layer, said innermost layer having a physical thickness ranging from 50 to 500 nm, preferably 100 to 300 nm and being formed by vacuum evaporation deposition at a deposition rate of at least 1.10 nm/s and/or maintaining a pressure higher than or equal to 1 x10-4 mbar, preferably ranging from 1.2 x 10-4 mbar to 5 x 10-4 mbar in said vacuum chamber by introducing inside said vacuum chamber at least one gas selected from the group consisting of oxygen, an inert gas or a mixture thereof.