Patent ID: 7262820
Filing Date: 2007-08-28
Classification: G02F

Abstract:
1. A liquid crystal panel disposed on an optical path of a light beam for compensating wavefront aberration that occurs between an optical axis of the light beam and an information recording surface in an recording medium by providing phase difference to the light beam, the panel comprising: a first electrode portion constituted by plural partial electrodes for providing phase differences different with respect to each of the partial electrodes to the passing light beam; and a second electrode portion disposed adjacent to the first electrode portion and constituted by at least one partial electrode for providing phase difference different from those of the first electrode portion to the passing light beam; wherein the second electrode portion provides phase difference to the passing light beam by the partial electrode in the case where misalignment within a plane perpendicular to the optical axis occurs between a position of a central axis of a condensing device for condensing the light beam on the information recording surface and a position of a central axis of the liquid crystal panel, wherein the second electrode portion is provided outside a range of luminance flux of the light beam, wherein the first electrode portion includes a long-and-narrow partial electrode adjacent to the second electrode portion; and wherein a majority of the long-and-narrow partial electrode is provided inside the range of the luminance flux of the light beam.