| 摘要 |
PROBLEM TO BE SOLVED: To obtain a substrate for a phase transition optical disk having a high header reading rate and a phase transition optical recording medium by elucidating a preformat part shape. SOLUTION: The ratio of the land center length Ylc1 and groove center length Ygc1 of the parts where the shortest signal pits continue of a preformat substrate used for the phase transition type optical disk is specified to Ylc1/(Ylc1+Ygc1)=0.48±0.05, by which the substrate for the optical disk having the high reading rate (hereafter described as the header reading rate) in reproducing of prepit parts and the optical recording medium using the same are embodied. |
