An optical pickup apparatus used in an optical data recording/reproducing apparatus for reading/reproducing data on an optical recording medium, including a light source, a diffracting device configured to transmit a light beam and to diffract a light beam reflected from the optical recording medium,...http://www.google.de/patents/US20010026523?utm_source=gb-gplus-sharePatent US20010026523 - Optical pickup apparatus, optical data recording/reproducing apparatus, and optical data recording/reproducing method
