OPTICAL DISC DEVICE, VIDEO REPRODUCING APPARATUS, SERVER, CAR NAVIGATION SYSTEM USING THE OPTICAL DISC DEVICE, INTEGRATED CIRCUIT AND RECORDING/REPRODUCING METHOD

摘要

An optical disc device is provided with an optical head (1) including a light source (21), a condensing optical system including an objective lens (28) for receiving a light beam emitted from the light source and forming a microspot on a multilayer optical recording medium, a photodetector (201) for receiving the light beam reflected by the multilayer optical recording medium and outputting an electrical signal corresponding to the amount of light and a coma aberration correcting element (26) for correcting a coma aberration of the condensing optical system, and a processing circuit (3) for controlling the condensing optical system and the coma aberration correcting element. The processing circuit controls the condensing optical system and the coma aberration correcting element so that the correction of the coma aberration from a value suitable for a first recording layer to a value specified for a second recording layer is started before a movement of a focus position of the microspot from the first recording layer to the second recording layer is completed.