| 摘要 |
PROBLEM TO BE SOLVED: To perform stable tracking control in plural kinds of disk areas. SOLUTION: This device is provided with a photodetecting means 21 divided into first to fourth light receiving areas by dividing lines corresponding to a track tangential direction and its orthogonal direction, first to fourth delay means 22 for delaying signals obtained from the first to fourth light receiving areas, a determination means 27 for determining the type of a disk recording medium, a delay control means 28 for delaying signals output from the first and second light receiving areas positioned on an upstream side with respect to the rotational direction of the disk recording medium by the first and second delay means, or selectively delaying signals output from the third and fourth light receiving areas positioned on a downstream side with respect to the rotational direction of the disk recording medium by the third and fourth delay means, and a tracking control signal generation means for generating a tracking control signal from signals output from the first to fourth delay means. COPYRIGHT: (C)2006,JPO&NCIPI
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