Patent ID: 7990836
Filing Date: 2011-08-02
Classification: G11B

Abstract:
1. An optical pickup apparatus, comprising: a laser light source; an objective lens for converging a laser light emitted from the laser light source onto a recording medium; an astigmatic element for introducing an astigmatism into the laser light reflected by the recording medium so as to mutually space a first focal line position occurring by convergence of the laser light in a first direction and a second focal line position occurring by convergence of the laser light in a second direction vertical to the first direction, in a propagation direction of the laser light; an angle adjusting element for mutually contradicting propagation directions of luminous fluxes, out of the laser light reflected by the recording medium, within four different luminous flux regions so that the luminous fluxes within the four luminous flux regions are mutually dispersed; a photodetector for outputting a detection signal when receiving each of the dispersed luminous fluxes; and a coma-aberration correcting unit for correcting a coma aberration occurring in the laser light,