METHOD FOR DRIVING LIQUID CRYSTAL OPTICAL ELEMENT, OPTICAL HEAD DEVICE, AND LIQUID CRYSTAL OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a method for driving a liquid crystal optical element compatible among a plurality of information recording layers in plural types of multilayer optical disks without increasing transparent electrodes of the liquid crystal optical element, and also to provide an optical head, and the liquid crystal optical element.;SOLUTION: The liquid crystal optical element 10 has a liquid crystal layer 13 divided into a plurality of areas by a plurality of circular transparent electrodes different in size arrayed concentrically. The plurality of transparent electrodes is constituted of electrode patterns for reducing a spherical aberration caused by a difference in substrate thickness between information recording layers of a two-layer BD. When a voltage is applied to the plurality of transparent electrodes so as to reduce a phase difference added to a luminous flux transmitted through the liquid crystal optical element 10 by the plurality of areas from the center of the liquid crystal optical element 10 to the outer periphery, the plurality of areas give a phase difference for reducing a spherical aberration based on a difference in substrate thickness between the information recording layers of a two-layer HD, to the luminous flux transmitting through the liquid crystal optical element 10.;COPYRIGHT: (C)2010,JPO&INPIT