Patent ID: 7910215

Claim:
A transparent substrate comprising an antireflection coating made of a thin-film multilayer (A) of dielectric material with alternately high and low refractive indices, wherein the multilayer successively comprises, starting from the surface of the substrate: a high-index first layer ( 1 ) having a refractive index n 1 of between 1.8 and 2.2 and a geometrical thickness e 1 of between 10 and 25 nm; a low-index second layer ( 2 ) having a refractive index n 2 of between 1.40 and 1.55 and a geometrical thickness e 2 of between 20 and 50 nm; a high-index third layer ( 3 ) having a refractive index n 3 of between 1.8 and 2.2 and a geometrical thickness e 3 of between 110 and 150 nm; and a low-index fourth layer ( 4 ) having a refractive index n 4 of between 1.40 and 1.55 and a geometrical thickness e 4 of between 60 and 95 nm, the algebraic sum of the geometrical thicknesses e 3 +e 1 being between 125 and 160 nm, in that said multilayer (A) does not have a Zr dopant and in that said multilayer is present on at least one of the faces of said substrate, the other face being bare, covered with another coating having another functionality, or covered with another antireflection multilayer (A), wherein the high-index first layer ( 1 ), the high-index third layer ( 3 ) or both are based on silicon nitride, aluminum nitride, mixed tin/zinc oxide, mixed zinc/titanium oxide, silicon/titanium oxide, or a combination thereof.