| 摘要 |
PURPOSE:To improve recording density while securing C/N by obtaining a track cross signal having sufficient strength which permits accurate access even if a track pitch is set to be about 1.4mum and also preventing reflectivity on a land 3 from decreasing. CONSTITUTION:The width of a group 2 formed on a transparent substrate of an optical memory 15 is set to be 0.3-0.4mum and the depth of the group 2 is set to be 80-100nm, and further, the allowable maximum decreasing amount in the width direction at the corner part of the land 3 is set to be 0.2mum. |
