| 摘要 |
PURPOSE:To realize a stable tracking servo. CONSTITUTION:On an optical disk 1, information is recorded and reproduced in both of a land section 2 and a groove section 3. The ratio of the width of the section 2 to that of section 3 is either (55 to 65):(45 to 35) or (35 to 45):(65 to 55). Moreover, on the disk 1, the sub-beam interval in the radial direction on the disk 1 is approximately 1/2 of the track pitch while detecting a tracking error using a three beam method. Thus, the period of tracking error signals becomes a normal period equivalent to the track pitch, a tracking error is detected using the three beam method and the tracking error signal becomes stable. |
