OPTICAL PICKUP, OPTICAL RECORDING AND REPRODUCING DEVICE AND TRACKING ERROR SIGNAL DETECTION METHOD

摘要

PROBLEM TO BE SOLVED: To suppress an increase in weight of a movable part and degradation in light use efficiency by detecting objective lens shift by adding fourth-order aberration to return light.;SOLUTION: The optical pickup has a light source part, a light receiving part, an objective lens, an optical system guiding out-going light from the light source part to the prescribed position of the optical recording medium through the objective lens, an optical system converging return light from the optical recording medium on the light receiving part through the objective lens, and an objective lens drive part driving the objective lens based on light output detected by the light receiving part. An aberration adding part 8 for adding fourth-order aberration is provided between the optical recording medium and the light receiving part, the first and the second regions 81a and 81b, 82a and 82b of the aberration adding part 8 are made regions with different diffraction directions.;COPYRIGHT: (C)2008,JPO&INPIT