Patent ID: 6829205
Filing Date: 2004-12-07
Classification: G11B

Abstract:
An optical pickup, comprising:a laser configured to output a laser beam; a diffraction grating configured to diffract the laser beam from said laser to generate a 0th order diffraction beam and +-first order diffraction beams which have a phase distribution equal to or substantially equal to a phase distribution due to a wave front aberration generated on an optical disk when the optical disk is tilted; an objective lens configured to collect said 0th order diffraction beam and said +-first order diffraction beams and exposing the beams to the optical disk on which track guide grooves are formed; and a photodetector configured to generate signals corresponding to said +-first order diffraction beams reflected at said optical disk, wherein; said exposing step has the steps of collecting said 0th order diffraction beam and +-first order diffraction beams and exposing said 0th order diffraction beam to the track of said optical disk, and a distance from the center part of the optical spot of said 0th order diffraction beam to the center part of the optical spot of said +-first order diffraction beams in the disk radial direction is, where n is an integer of 0 or more, equal to or approximately equal to a (n/2+Â¼) times of the pitch of said track or said track guide groove.