Patent ID: 6243350
Filing Date: 2001-06-05
Classification: B82Y,G11B

Abstract:
An optical system with passive thermal compensation for a near-field optical storage system, comprising:a lens support base made of a base material having a prespecified coefficient of thermal coefficient;at least a first lens that is made of a first lens material with a prespecified first lens dimension, a prespecified first temperature dependence of refractive index, and a first lens coefficient of thermal expansion;a first lens holder affixed to said lens base at at least a first point, said first lens cell holding said first lens relative to said first point; anda laser disposed to produce a laser beam that transmits through said first lens, said laser having a known temperature dependence of the laser wavelength, wherein a dispersion property of said first lens and said prespecified first lens dimension are chosen such that a change in a focus of said laser beam caused by a shift in the laser wavelength due to a temperature change over a prespecified temperature range is limited within a focus tolerance range.