OBJECTIVE LENS, OPTICAL PICKUP DEVICE, AND RECORDING/REPRODUCING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide an optical pickup device capable of recording or reproducing information in three types of optical information recording media of different standards.

SOLUTION: The optical pickup device reproduces and/or records information in a first optical information recording medium having a first protective substrate of a thickness t1 by using a light flux of a wavelength λ1 from a first light source 1, and reproduces and/or records information in second and third optical information recording media having second and third protective substrates of a thickness t2 and a thickness t3 (t3>t2>t1) by using light fluxes of a wavelength λ2 and a wavelength λ3 (λ1<λ2<λ3) from a second light source 2 and a third light source 3, respectively. The optical pickup device has substrate thickness difference correcting means 7 for correcting spherical aberrations changed due to a difference in thickness among the first protective substrate to the third protective substrate by using a common objective lens 8 constituted of one lens group for information reproducing and/or recording in the first to third optical information recording media.

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