| 摘要 |
<P>PROBLEM TO BE SOLVED: To compensate spherical aberration stably while detecting a lens shift amount only by a light receiving element even when a liquid crystal element is not integrated to an objective lens. <P>SOLUTION: In a state in which a liquid crystal element 20 is arranged independently from an actuator 8 for shifting an objective lens 2, a liquid crystal element shifting mechanism which moves the liquid crystal element 20 to the same direction as that of the lens shift is provided. The transparent electrode part of the liquid crystal element 20 is formed by precedence of the reduction of wave front aberration and the liquid crystal element 20 is moved while calculating a relative lens shift amount which can be observed only by the light receiving element 4 by step-movement derived by operation based on the calculated lens shift amount. <P>COPYRIGHT: (C)2004,JPO |
