Optical pickup

Abstract

An optical pickup for irradiating a light beam onto an information recording medium and receiving a light reflected by the medium, includes a light source for emitting a light beam, and a liquid crystal panel for diffracting the light beam to produce a main beam and a plurality of sub-beams to be irradiated on the medium. The liquid crystal panel included a first area in which a first group of grating patterns with predetermined pitches is formed and a second area in which a second group of grating patterns having the predetermined pitches is formed, and the first group of grating patterns and the second group of grating patterns are arranged on a plane with a gap area formed between the first area and the second area so as to form an integrated grating pattern. The optical pickup further includes a control unit for applying a first voltage to the first area to control a refractive index of the first area and applying a second voltage to the second area to control a refractive index of the second area, thereby to control a diffraction characteristic of the integrated grating pattern.