Optical pick-up device and objective lens therefor

摘要

In an optical pickup apparatus provided with a first light source (111); a second light source (112); a converging optical system having an objective lens (3) provided with a diffractive section, and an optical detector (10), the optical detector comprises a central light receiving section (10a) to detect a focusing condition and a peripheral light receiving section (10b) to detect a tracking error, and when information is reproduced from or recorded in the second optical information recording medium, a reflected light flux of the second light flux reflected from or a transmitted light flux of the second light flux transmitted through the second optical information recording medium is irradiated so as to cover the entire surface of the peripheral light receiving section.