OPTICAL PICKUP DEVICE, OBJECTIVE LENS, DIFFRACTIVE OPTICAL ELEMENT, OPTICAL ELEMENT, AND RECORDING/REPRODUCTION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical pickup device which can perform recording or reproduction of information for three kinds of optical information recording mediums which differ in specifications.;SOLUTION: The optical pickup device performs reproduction and/or recording of information to a first optical information recording medium comprising a first protective substrate of thickness t1 by using a luminous flux from a first light source 1 of wavelength λ1; and performs reproduction and/or recording of information to second and third optical information recording mediums comprising second and third protective substrates of thicknesses t2 and t3 (t3t2t1) respectively by using luminous fluxes from a second light source 2 and a third light source 3 of wavelengths λ2 and λ3 (λ1λ2λ3) respectively. The optical pickup device has a substrate thickness difference correction means 7 for correcting spherical aberration which changes due to differences in thickness from the first protective substrate to the third protective substrate by using a common objective lens 8 which consists of one lens group for reproduction and/or recording information to from the first to the third optical information recording mediums.;COPYRIGHT: (C)2007,JPO&INPIT