OBJECTIVE LENS, AND OPTICAL HEAD USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an objective lens capable of controlling the occurrence of aberration even when it is used in common with respect to two wavelengths by utilizing a module wherein two semiconductor lasers are incorporated into one package. SOLUTION: The objective lens is formed so that the rotation axis 16' of a second surface of the objective lens 16 tilts relative to the rotation axis of a first surface which coincides with a reference axis 10'. In the virtual state that rotation axes coincide with each other, when a breaching quantity of a sine condition in the outer peripheral part of the objective lens when laser beams of short wavelength the condensed on a first optical disk is expressed by SC1 and a breaching quantity of a sine condition in the outer peripheral part within a shared area when laser beams of long wavelength are condensed on a second optical disk is expressed by SC2, -4.0