Objective lens and optical pickup device

摘要

An objective lens capable of converging light of a used wavelength with a satisfactory aberration on a recording medium is provided. An objective lens for converging light of a predetermined wavelength λ on a recording medium satisfies the following condition: |CML|+|CMF|<0.03λ, where CML is an amount of a generated third-order coma aberration per 1 degree of tilt of the objective lens, and CMF is an amount of a generated third-order coma aberration per 1 degree of tilt of off-axis light.

主权项

1. An objective lens, wherein:
the objective lens is configured to converge light of a predetermined wavelength λ on a recording surface of a recording medium, the recording surface being provided at an uppermost surface of the recording medium or at a lower layer beneath a cover layer provided at an uppermost layer of the recording medium, the thickness of the cover layer being not more than 10 μm, and the objective lens satisfies the following condition:
|CML|+|CMF|<0.03λ, where CML is an amount of a generated third-order coma aberration per 1 degree of tilt of the objective lens, and CMF is an amount of a generated third-order coma aberration per 1 degree of tilt of off-axis light.