Objective lens for optical pick-up devices, optical pick-up devices, and optical information recording and/or reproducing apparatus

摘要

The present invention provides an objective lens for optical pick-up devices in which the amount of change in the astigmatic aberration is small when there is a temperature distribution that is not circularly symmetric with respect to the optical axis within an objective lens constructed with at least two optical elements and which permits stable and highspeed information recording and reproduction with high-density optical disks, and to provide further an optical pick-up device provided with such an objective lens, and an optical information recording and/or reproducing apparatus employing such an optical pick-up device.