| 摘要 |
PCT No. PCT/JP88/00844 Sec. 371 Date Oct. 11, 1988 Sec. 102(e) Date Oct. 11, 1988 PCT Filed Aug. 25, 1988 PCT Pub. No. WO89/02150 PCT Pub. Date Mar. 9, 1989.A lens is accelerated on a coarse tracking carriage while enabling a lens position servo, which moves the carriage so that the lens returns to a neutral position on the carriage. After the beam spot becomes fast enough, the carriage is accelerated and decelerated until the beam spot arrives near a destination track; then, the lens is decelerated on the carriage to stop on the destination track. The method does not require a stop at each track which is to be crossed. In a second method, the carriage is first accelerated while the fine tracking servo is enabled to trace a start track. After the carriage becomes fast enough that eccentricity of the tracks will not prohibit a correct jump, the fine tracking servo is disabled. The beam spot is then moved by a lens lock force which returns the lens to the neutral position on the carriage. The carriage is further accelerated and decelerated, and then the lens is decelerated in the same manner as the first method.
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