| 摘要 |
PROBLEM TO BE SOLVED: To improve precision in reading data from an optical disk and (or) writing data to the optical disk by an optical head and to improve reliability by suppressing friction between a shaft hole and a shaft by simple structure so as to suppress occurrence of unnecessary resonance in the case of focusing. SOLUTION: The optical disk has a focusing coil 214 arranged so as to surround a cylindrical part 212, an upper magnetic plate 216 arranged on the upper surface of the focusing coil 214, and a lower magnetic plate 217 arranged on the lower surface of the focusing coil 214. The upper magnetic plate 216 and the lower magnetic plate 217 are arranged deviated in mutually opposite directions from a magnetic field formed by a permanent magnet 224 and the shaft 223. COPYRIGHT: (C)2007,JPO&INPIT
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