GUIDE-LAYER SEPARATED OPTICAL DISK, OPTICAL DISK DRIVE APPARATUS, AND TRACKING CONTROL METHOD

摘要

A guide-layer separated optical disk which includes a guide layer having a guide structure whose tracking guide tracks are divided into areas by discontinuous portions, the areas each having concentric guide tracks of arc shape at a regular track pitch, the guide tracks in adjoining two of the areas across one of the discontinuous portions deviating from each other in a radial direction of the disk by ¼ the track pitch. An optical disk drive apparatus and a tracking control method in which a servo optical system switches the tracking center of the irradiation spot of a first laser beam between on the guide tracks and in between the guide tracks alternately each time the irradiation spot passes two of the discontinuous portions.