Objective lens, optical pickup device, recorder and reproducer

Abstract

An objective lens is provided in an optical pickup device for carrying out the reproduction/record for a plurality of optical information storing media in which the protect substrates of the mediums have a different thickness. 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 light amount of the k-th order diffracted light can be suppressed more than the (k−1)-th order diffracted light.