| 摘要 |
PURPOSE:To stably perform tracking control, by performing track seek by applying tracking by a phase difference method by using a track mark of pit shape, and counting consecutive grooves formed in a concentric circle or a spiral shape. CONSTITUTION:A recording medium 2 is formed in a disk shape, and also, the track mark 2p of pit shape and consecutive grooves 2g are formed in the concentric circle or the spiral shape on the medium. An optical head 1 reads those, and imprints the far-field patterns of them on a photodetector 11. A light quantity detector 3 synthesizes two detecting signals A and B from the output of the photodetector 11. Thus, it is possible to realize the tracking control stably without lowering the performance of the track seek by applying the tracking by the phase difference method by using the track mark, and counting the grooves. |
