Optical pickup, information recording apparatus and information reproducing apparatus

Abstract

An optical pickup is provided with: a light emitting device for emitting a light beam onto a record medium comprising a transparent layer, which is transparent for the light beam and through which the light beam is transmitted; a light receiving device for receiving a reflection light of the light beam from the record medium; a liquid crystal compensating device for compensating birefringence, which is generated in the light beam when the light beam is transmitted through the transparent layer, by controlling an orientation direction of liquid crystal molecules in a liquid crystal layer so as to give a canceling phase difference to the light beam transmitted through the liquid crystal layer; a generating device for generating an indication signal indicative of the birefringence; and a controlling device for controlling the orientation direction on the basis of the indication signal so that a first angle between a standard line, which is perpendicular to an optical axis of the light beam and is set in advance, and the orientation direction in a plane perpendicular to the optical axis is kept to be constant and that a second angle between the optical axis and the orientation direction in a plane including the optical axis is changed, to thereby generate the canceling phase difference in the light beam transmitted through the liquid crystal compensating device.