| 摘要 |
PURPOSE:To attain a large capacity by recording information both in a pregroup and its adjacent pregroup. CONSTITUTION:In terms of an optical disk comprising by forming a recording layer 3 on an optical disk substrate 1 through a protective layer 2, information is recorded both in the pregroup 5 and its adjacent pregroup. With the advanced tracking technique the pitch of the pregroup 5 is reduced to 1.6mum from 2.5mum. On the other hand a projection part lying in a groove between the pregroups remains flat. Thus a recording density can be substantially improved, and information can be correctly read out by forming an ID part installed the top of the pregroup at a shifted position. |
