Patent ID: 8142896

Claim:
An article comprising a substrate having at least one main surface coated with a multi-layer anti-reflection stack, wherein the multi-layer anti-reflection stack comprises, in the order indicated starting from the substrate: (a) a high index (HI) layer, having a refractive index n D 25 of 1.50 to 2.00 and resulting from the hardening of a first hardenable composition and comprising an organic-inorganic hybrid matrix resulting from the hydrolysis and condensation of at least one precursor compound bearing an epoxy or (meth)acryloxy group and at least two functions hydrolysable to silanol groups, within which at least one colloidal metal oxide or at least one colloidal chalcogenide or a mixture of these compounds is dispersed in the form of particles from 2 to 50 nm in diameter, and directly on this high index layer (HI): (b) a low index (LI) layer, having a refractive index n D 25 ranging from 1.38 to 1.44 obtained by deposition and hardening of a second hardenable composition and comprising the product of hydrolysis and condensation of: (i) at least one precursor compound (I) comprising four hydrolysable functions per molecule of formula Si(W) 4 in which the groups W, identical or different, are hydrolysable groups and provided that the groups W do not all represent at the same time a hydrogen atom, (ii) at least one precursor silane (II) bearing at least one fluorinated group and comprising at least two hydrolysable groups per molecule, said second composition comprising at least 10% by mass of fluorine in its theoretical dry extract (TDE), and the molar ratio I/(I+II) of the precursor compound (I) to the sum of the precursor compound (I)+precursor silane (II) of the second composition is at least 90%.