| 摘要 |
PROBLEM TO BE SOLVED: To provide an error signal generation circuit not affected by a dead zone even when a condensing spot is located near a just track, and an optical information reproducing device using the same. SOLUTION: A light receiving part 1 receives lights reflected from an optical disk, and photoelectrically converts the reflected lights to output light receiving signals A to D. Delay circuits 2 and 3 correct times differences between the light receiving signals A and B and the light receiving signals C and D. Adders 4 and 5 adds together light receiving signals from two sets of light receiving cells located on the diagonal line of the light receiving part 1. Binarization circuits 7 and 6 binarize output signals A+D and B+C from the adders 4 and 5. A delay circuit 11 outputs a delay signal A+D+d obtained by delaying the binarized output signal A+D by a predetermined time. A phase comparator 8 compares a phase relation between the binarized delay signal A+D+d and the output signal B+C, and outputs pulse signals P1d and P2d according to the phase relation. COPYRIGHT: (C)2008,JPO&INPIT
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