OPTICAL PICKUP DEVICE, OPTICAL INFORMATION RECORDING/REPRODUCING DEVICE, EXPANDER LENS, COUPLING LENS, AND OPTICAL ELEMENT FOR CHROMATIC ABERRATION CORRECTION

摘要

PROBLEM TO BE SOLVED: To provide an optical pickup device, an optical information recording/reproducing device, an expander lens, a coupling lens and an optical element for chromatic aberration correction suitable for miniaturization or the like while maintaining compatibility for two or more kinds of optical disks such as a high density optical disk of a different laser light source wavelength.;SOLUTION: The optical pickup device is provided with a light source for emitting the luminous fluxes of a wavelength λ1 and a wavelength λ2, an objective lens unit, and an optical unit for chromatic aberration correction and an optical unit for spherical aberration correction arranged in the common optical path of the first luminous flux and the second luminous flux between the light source and the objective lens unit. Then, the optical unit for the spherical aberration correction changes the tilting angle of the marginal light beam of an incident luminous flux on the object lens unit by variably adjusting the interval of the constituting lens group and the objective lens unit. Further, the optical unit for the chromatic aberration correction is provided with a diffraction plane and is designed such that the diffraction order of the second luminous flux having the maximum diffraction efficiency is lower than the diffraction order of the first luminous flux.;COPYRIGHT: (C)2005,JPO&NCIPI