CHROMATIC ABERRATION-CORRECTING OPTICAL SYSTEM AND OPTICAL PICKUP DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a chromatic aberration-correcting optical system which corrects chromatic aberration for a high-density recording medium employing a large numerical aperture and at the same time does not affect securing compatibility with incidence of light to at least one low-density recording medium.

SOLUTION: The chromatic aberration-correcting optical system for correcting chromatic aberration in light beams for the high-density recording medium includes a chromatic aberration correcting element, wherein the chromatic aberration correcting element includes at least one concave surface for converting the light beams for the high-density recording medium and at least one low-density recording medium with divergent or convergent light beams, and at least one diffraction surface for converting the divergent or convergent light beams with parallel light beams, thereby realizing compatible adoption of light beams for the high-density recording medium and at least one low-density recording medium.

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