| 摘要 |
PROBLEM TO BE SOLVED: To precisely jump and move an optical pickup to the vicinity of target track position even when the decentering error of a track exists in an optical disk. SOLUTION: First, the ideal (true-circle) radii ri and rj of a present track TRi and a target track TRj are calculated. Then, the difference between the radii ri and rj of both tracks is calculated as the distanceΔr between the tracks. In addition, a decentering amount ei in the present position of an optical pickup 12 is calculated. Then, a temporary seek distance x' (namely,Δr-ei) is found. Then, a temporary seek time T' (namely x'/v) is found. Then, on the basis of the temporary seek time T', the track radius rj of the target track TRj, the angular velocityωand the present angle positionϕa, the position (rj,ϕb) of a virtual arrival point PCj on the true circle Cj corresponding to the target track TRj when the optical pickup 12 is moved to the radial direction of the disk by the temporary seek time T' is found. Then, the decentering amount ej at the virtual arrival point PCj is found. Then, on the basis of the temporary seek distance x' and the decentering amount ej, a seek distance (x) is found.
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