| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk drive for generating an accurate tracking error signal even in the case that a movement direction of a light spot changes in a multilayer disk.SOLUTION: Three beams (a main spot 20 and two sub spots 21, 22) are irradiated to an optical disk recording surface, and a tracking error signal is generated by a differential push-pull system. In the case that light spots for recording are moved from an outer circumference in an inner circumferential direction, detection signals from the two sub spots 21, 22 are respectively divided into detection signals (E, G) of an inner circumferential side light reception surface and detection signals (F, H) of an outer circumferential side light reception surface, and gain correctors 47, 48 perform gain correction of a detection signal from each sub spot such that respective gains of an addition signal (E+G) of an inner circumferential side detection signal and an addition signal (F+H) of an outer circumferential side detection signal become constant. |
