| 摘要 |
PURPOSE:To discriminate inter-group gap of tracks on a disk by dividing the tracks on the disk into several groups and by making those groups different in shape and in optical characteristics. CONSTITUTION:Information recording track areas (group) 15 are formed by recording information in grooves as pits, or by recording information as pits by utilizing the variation of the reflectance of a photosensitive recording material applied on an optical disk 2 by exposing it to a projected light spot. A tracking error signal 9 is obtained from a signal waveform when the light spot crosses the track, and no track traverse signal is outputted when the light spot scans inter-group gap 16 where no track is provided, thereby discriminating inter-group gap 16 easily during retrieval when the light spot scans inter- group gap 16. |
