Antireflecttion-coated transparent substrate exhibiting neutral colour in reflection

摘要

Transparent especially glass, substrate (6) having at least on one of its sides an antireflection coating made from a stack (A) of thin dielectric layers of alternating high and low refractive indices, characterized in that the stack comprises, in succession: a high-index first film (1) having a refractive index n1 between 1.8 and 2.3 and a geometrical thickness e1 of between 10 and 25 nm; a low-index second film (2) with a refractive index n2 of between 1.40 and 1.55 and a geometrical thickness e2 of between 20 and 50 nm; a high-index third film (3) with a refractive index n3 of between 1.8 and 2.3 and a geometrical thickness n3 of between 110 and 150 nm; and a low-index fourth film (4) with a refractive index n4 of between 1.40 and 1.55 and a geometrical thickness e4 of between 60 and 95 nm, the algebraic sum of the geometrical thickness e3+e1 being between 125 and 160 nm.