Optical element and optical pickup apparatus

摘要

An optical element for use in an optical pickup apparatus includes a substrate made of resin; an antireflection layer coating the substrate and having a low refractive index layer and a high refractive index layer, wherein the resin includes a polymer with an alicyclic structure, the low refractive index layer is formed of a material selected from the group consisting of silicon oxide; aluminum fluoride; yttrium fluoride; magnesium fluoride; a mixture of silicon oxide and aluminum oxide; and a mixture thereof, the high refractive index layer is formed of a material selected from the group consisting of scandium oxide; niobium oxide; lanthanum oxide; praseodymium titanate; lanthanum titanate; lanthanum aluminate; yttrium oxide; hafnium oxide; zirconium oxide; tantalum oxide; a mixture of tantalum oxide and titanium; silicon nitride; and a mixture thereof.