| 摘要 |
<P>PROBLEM TO BE SOLVED: To increase the degree of flexibility in design, to provide a configuration for correcting spherical aberration, and to reduce the size/weight of the capacity of a movable section. <P>SOLUTION: A liquid crystal element 27 used as a diffraction means for obtaining a spherical aberration correction signal is made independent of an objective lens, and an objective lens actuator 26 for driving the objective lens and a liquid crystal element actuator 28 are provided. The liquid crystal actuator 28 has nearly the same structure as the objective lens actuator 26 and separately retains the liquid crystal element 27. The liquid crystal element actuator 28 is controlled by a servo control section 109 so that the center in the liquid crystal pattern of the liquid crystal element 27 coincides with an optical axis. The liquid crystal element actuator 28 is driven in synchronization with movement in the tracking direction of the objective lens actuator 26 by utilizing a tracking servo signal, thus separating the liquid crystal element 27 from the objective lens 25 for arranging at an arbitrary position in parallel light. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
