Optical disc, information recording apparatus and information reproducing apparatus therefor

摘要

An optical disc has an information recording portion. The information recording portion has a spiral of a groove, and land portions located between portions of the groove which neighbor each other as viewed in a disc radial direction. Auxiliary information used when an information signal is recorded on and reproduced from the groove is previously recorded on the land portions. The auxiliary information is represented by pre-pits provided in the land portions. The information recording portion is divided into a plurality of zones as viewed in the disc radial direction. In each of the zones, at least one of two sides of the groove wobbles at a fixed frequency in accordance with a constant angular velocity system. In each of the zones, phases of wobbles of respective neighboring portions of the groove are equal to each other.