| 摘要 |
PURPOSE:To reduce the offset of a tracking error signal due to the shift of an objective lens produced in the tracking direction by a splitting/focusing element and a multi-split photodetector to form a tracking error signal detection means. CONSTITUTION:A light source 1 is provided together with an objective lens 3, a 2-split detection means 5, and a focus/tracking servo application means 6. Then a tracking error signal detection means consists of a splitting/focusing element 8 which splits and focuses the reflected light sent from an information recording medium 4 and a multi-split photodetector 5. Thus the lens 3 moves from a neutral position of a movable range set in the tracking direction. As a result, the offset is reduced and the quality is improved for the tracking error signal which is obtained as an output even if an optical spot moves on the photodetector. |
