Optical article having a multilayered antireflective coating including an encapsulated metal film

Abstract

This invention relates to an optical article comprising a transparent substrate with a front main face and with a rear main face, at least one of the main faces being coated with a multilayered antireflective coating comprising at least one low refractive index layer (LI) having a refractive index lower than 1.55 at 550 nm, named hereafter first LI layer, one first high refractive index layer (HI) having a refractive index higher than or equal to 1.55 at 550 nm, named hereafter the first HI layer, and one encapsulated metal film (EMF) comprising a metal island layer (MIL) that is encapsulated between a first layer (L1) and a second layer (L2), said first layer (L1) and said second layer (L2) being both composed of at least one dielectric material, characterized in that said —the first layer (L1) is a second LI layer having a refractive index lower than 1.55 at 550 nm and has a physical thickness equal to or higher than 10 nm, —the metal island layer (MIL) has plasmonic effects and has an effective thickness ranging from 0.2 nm to 4 nm, preferably ranging from 0.5 to 4 nm, —the second layer (L2) has a physical thickness equal to or higher than 10 nm, wherein said multilayered antireflective coating has a mean light reflection factor in the visible region Rv on the front face and/or on the rear face of said optical article that is equal to or lower than 2.5% for at least an angle of incidence lower than 35°, preferably for an angle of incidence of 0°. The absorption of said AR stack is mainly due to said MIL layer.