Patent ID: 7773488

Claim:
An information reproducing apparatus, comprising: a medium drive unit for fixing and driving an optical recording medium having multiple recording layers; a light source; an objective lens for focusing light from the light source on the optical recording medium; an objective lens drive unit for driving the objective lens in a focusing direction; a liquid crystal lens element having a discontinuous switching type of lens arranged in an optical path from the light source to the optical recording medium for correcting spherical aberration associated with an interlayer switching between one recording layer to another recording layer on the optical recording medium; a photo-detector for detecting a focal error amount based on differences in the amount of light returning from the optical recording medium; feedback control means for feeding back the focal error amount to the objective lens drive unit for controlling a focus position; and means for applying a focus bias to a target position of the feedback control in accordance with a direction of the interlayer switching and in synchronization with the interlayer switching of the liquid crystal lens element.