| 摘要 |
PURPOSE:To fetch a velocity signal for constant linear velocity(CLV) control from an optical disk by previously forming a pit string for detecting velocity on tracking guide grooves formed along tracks at an equal distance interval. CONSTITUTION:The information recording tracks 12 and the tracking guide grooves 14 are formed and the control pits 16 for detecting a reference clock for CLV control are formed on the grooves 14 at the equal distance interval. Namely, the grooves 14 are spirally formed on the surface of the optical disk 10 in parallel with the tracks 12 and the string of control pits 16 with the same size is previously formed on the grooves 14 at the fixed distance interval. Since the intervals of the control pits 16 are set so that distances l along the trace lines of the grooves 14 are equal, the same number of control pits 16 can be detected at any position in the radius direction of the optical disk when the rotational linear velocity is equal. |
