| 摘要 |
PURPOSE: To stabilize access performance to achieve high recording density through the improvement of track loss signal of an opticak disk having grooves and to assure the compatibility of the tracking control of the recording/ reproducing area and reproduction-only area of the partial ROM disk. CONSTITUTION: In an optical disk, a value (p-w)/w obtained by dividing a value obtained by subtracting the width w of groove from a pitch p of groove, namely the width (p-w) of land with the width w of the groove is set outside the range from 0.95 to 1.1. In the partial ROM disk, such condition is satisfied and moreover the pitch of pit pp of the reproduction-only area is within the range from 55 to 65% of the pitch p of the groove in the recording/reproduction area. |
