| 摘要 |
PROBLEM TO BE SOLVED: To stably apply a track servo even though the recording density is increased, by allowing the increase of the amplitude of a track servo signal to be large even though the track pitch of the data recording/reproducing layer is shortened for increasing the recording density. SOLUTION: For the tracking servo in a control circuit, when the information is recorded/reproduced with respect to the track of recording layers 25 existing below lands 22a on the reflection surface 22, the track servo is applied to the lands 22a on the reflection surface 22 by a tracking error signal with the laser beam for servo. When the information is recorded/reproduced with respect to the track of the recording layers 25 existing below grooves 22b on the reflection surface 22, the polarity of the track servo is changed from one at the time of recording/reproducing operation of the track on the recording layers 25 existing below the lands 22a, then the track servo is applied to the grooves 22b on the reflection surface 22 by the tracking error signal with the laser beam for servo. |
