Patent ID: 8121013
Filing Date: 2012-02-21
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; and a photodetector having eight sensors for individually receiving eight luminous fluxes, the eight luminous being obtained by dividing a luminous flux of the laser light reflected by the recording medium into eight portions by first and second straight lines respectively parallel to the first and second directions and third and fourth straight lines each having an angle of 45 degrees relative to the first and second straight lines, wherein