| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device which can effectively suppress aberrations produced in the laser beam even if there is a lens shift in the objective lens. <P>SOLUTION: The wavefront of the laser beam is adjusted using a phase correction element. The phase correction element has an electrode layer 143 and an electrode layer 144 facing it, orientation films 145 arranged facing those electrode layers 143, 144, and a liquid crystal layer 146 filled between those orientation films 145. On the electrode layer 143, electrodes E11, E12, and E13 are provided to give a spherical aberration correction function to the laser beam which is within a certain distance from the center of the irradiated beam. and an electrode E14 is provided outside them without separation. Thus, the aberrations by the lens shift can be effectively suppressed by eliminating electrodes arranged slightly inside the irradiated beam diameter. <P>COPYRIGHT: (C)2007,JPO&INPIT |
