| 摘要 |
The present invention provides an optical pickup apparatus for recording and/or reproducing information for different kinds of optical information recording media. The optical pickup apparatus includes: a first light source for emitting a first light flux; a second light source for emitting a second light flux; a third light source for emitting a third light flux; a light-converging optical system including an objective lens. The objective lens includes at least one optical surface including a diffractive structure which includes a plurality of ring shaped zones. Each of the ring shaped zones is concentrically arranged around an optical axis and includes a step difference extending along the optical axis. In the objective lens of the optical pickup apparatus, the offence against a sine condition, an average of step differences of the plurality of ring shaped zones, focal length, and magnification satisfy the predetermined conditions.
|
