Optical information recording/ reproducing device and optical information recording/ reproducing method

Abstract

An optical information recording/reproducing device includes a liquid optical element containing a liquid crystal polymer layer in an optical head. A liquid crystal optical element drive unit drives a liquid crystal optical element having a first pattern electrode divided into a plurality of region at one side of the liquid crystal polymer layer in the optical axis direction. The first pattern electrode includes a first region arranged to surround the optical axis and second to ninth regions arranged outside the first regions in such a manner that the circumference is divided eight portions. The liquid crystal optical element drive unit applies a first effective voltage to the first region, a second effective voltage to the second and the sixth region, a third effective voltage to the third and the seventh region, a fourth effective voltage to the fourth and the eighth region, and a fifth effective voltage to the fifth and the ninth region. An average value of the second and the fourth effective voltage and an average value of the third and the fifth effective voltage are identical to the first effective voltage. The voltage applied to the respective regions of the pattern region of the liquid crystal optical element is decided in a short time so as to optimize the quality of the reproduction signal.