Patent ID: 8228776
Filing Date: 2012-07-24
Classification: G11B

Abstract:
1. Apparatus with a pickup for reading data from or writing data to an optical storage medium comprising a nonlinear layer for providing a super-resolution effect, the pickup comprising: a laser providing a laser beam, an objective lens for focusing the laser beam onto the optical storage medium, a first detector for providing a tracking signal and a second detector for providing a data signal, a first non-polarizing beam splitter arranged between the laser and the objective lens for guiding light reflected from the optical storage medium onto the first detector, and a collimator arranged in the optical path between the laser and the beam splitter for restricting the laser light to a center section of the objective lens, wherein a selecting means is arranged in front of the beam splitter, with regard to the reflected light from the optical storage medium, for guiding reflected light passing through an annular outer section of the objective lens onto the second detector, and for guiding reflected light passing through the center section of the objective lens onto the first detector, the selecting means comprises a half-wave plate having an annular shaped outer section arranged between the beam splitter and the objective lens, and, the pickup comprises a second beam splitter for guiding the light passing through the outer section of the objective lens and the half-wave plate onto the second optical detector, the second beam splitter being a polarizing beam splitter arranged between the first beam splitter and the half-wave plate.