Optical device and optical pickup device

摘要

An optical pickup apparatus has an optical system and an objective lens. The optical system has a semiconductor laser and an optical element. The semiconductor laser has an astigmatic difference in which an oscillated light beam has a light emission point in a semiconductor junction plane different from that in a plane normal to the semiconductor junction plane. The optical element is arranged in a light path of a light beam radiated from the semiconductor laser for over-correcting the astigmatic aberration of the light beam radiated from the semiconductor laser. The objective lens converges the light beam radiated by the light source via the optical element.