Optical pickup device and optical element

摘要

An optical pickup device includes a light source emitting a light beam having a wavelength within a range of 390 nm to 420 nm and an optical element to perform recording and/or reproducing of information of an optical disk having a protective substrate thickness d₁ mm using the first light beam from the first light source, wherein the optical element is made of a mixed material produced by dispersing particles into a resin, a sign of a refractive index change Deltan₂/Deltat of the particles owing to a temperature change is opposite to a sign of a refractive index change Deltan₁/Deltat of the resin owing to a temperature change, or an absolute value of the refractive index change Deltan₂/Deltat is smaller than an absolute value of the refractive index change Deltan₁/Deltat.