OPTICAL DISC AND OPTICAL DISC RECORDING/REPRODUCTION METHOD

摘要

It is possible to provide a run-in region bit pattern wherein data is sta bly reproduced even if the optical disc recording density is increased. Prov ided is an optical disc which has a plurality of tracks each track divided i nto a plurality of recording blocks. Each of the recording blocks has a run- in region and a data region. In the run-in region, a predetermined run-in bi t pattern can be recorded. The data region can be used for recording a bit p attern of various types of bit lengths obtained by modifying data to be reco rded according to a predetermined modulation rule. In the optical disc, amon g the bit patterns having the plurality of types of bit lengths, at least on e of the space frequencies corresponding to the respective bit patterns is h igher than the OTF cut-off frequency. The run-in bit patterns recorded in th e run-in region are the bit patterns excluding those having the space freque ncy higher than the OTF cut-off frequency among the bit patterns having the plurality of types of bit lengths.