OBJECTIVE OPTICAL SYSTEM, OPTICAL PICKUP DEVICE, AND OPTICAL INFORMATION RECORDING/REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a two-group constitution objective optical system having a phase structure, or the like having compatibility to a plurality of optical disks and efficiently manufactured at low costs to be high in performance for all used wavelengths.

SOLUTION: The objective optical system OBJ is provided with first and second lens groups L1 and L2, and the first lens group has a phase structure. When the wave surface aberration WL1λ1of the first lens group with respect to the parallel luminous flux of a wavelength λ1, and the wave surface aberration WL2λ1of the second lens group with respect to the luminous flux of a wavelength λ1are minimum, predetermined equations (1) to (6) are satisfied where the wave surface aberration of the objective optical system with respect to the parallel luminous flux of a wavelength λ1is WOBJλ1, and the wave surface aberration of the objective optical system with respect to the parallel luminous flux of a wavelength λ2is WOBJλ2.

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