| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical device capable of reducing spherical aberrations and the size of the device. <P>SOLUTION: Incidence and emission side lenses 23, 24 in a condensing unit 16 are fixed by a thermal expansion member 25 so that they can be displaced in the optical axis direction with respect to each other. When heat is generated by an actuator coil 17 in the light pickup device 10, the thermal expansion member 25 is displaced in the optical axis direction by the temperature change, thus reducing the spherical aberrations in the incidence and emission side lenses 23, 24. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
