| 摘要 |
It is to provide an objective lens for being provided in an optical pickup device for firmly carrying out the reproduction/record for each of a plurality of optical information storing media in which the protect substrates have different thicknesses from each other. The optical functional surface of the optical lens is divided into the central region including the optical axis and the peripheral region arranged outside the central region. The diffractive structure is provided on the peripheral region. When the reproduction and/or the record is carried out for the first optical information storing medium, the diffracted light is condensed on the focal point. When the reproduction and/or the record is carried out for the second optical information storing medium, among flare lights in which diffracted lights having various diffraction orders and passing through the peripheral region are mixed, the diffraction efficiency of the k-th order diffracted light is larger than the diffraction efficiency of the (k-1)th order diffracted light which causes a larger aberration than the k-th order diffracted light.
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