| 摘要 |
PURPOSE:To stably perform a track jump with high accuracy by storing a digital quantity corresponding to the eccentricity quantity of a disk in a memory, and adding a D/A converted eccentricity correcting analog voltage to the driving means of an objective lens. CONSTITUTION:Reflected light l1 and l2 from an optical disk 1 are detected at photodetectors 13a and 13b, then being supplied to a voltage comparator circuit 21 as a track differential signal voltage TS. The circuit 21 compares it with a reference voltage, and sets an adding/subtracting digital data B1, and the data B1 is stored on a memory 26 through a full adder 24. Also, in the memory 26, the eccentricity data of the disk 1 obtained from a signal FG which represents the rotating position of a spindle 3, is stored as a digital data B3. The data B3 is read out from the memory 26, and is rewritten to a data corrected based on the data B1, then it is outputted to a D/A converter 17 as a digital data B4, thereby a coil 6 which drives an objective lens 5 being driven. Thus, the track jump with high accuracy can be obtained stably.
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