Patent ID: 8737184

Claim:
A holographic optical pickup device for recording an information signal by irradiating an optical information recording medium with a reference beam and a signal beam to form a hologram, or reproducing the information signal by irradiating the hologram on the optical information recording medium with the reference beam, comprising: a light source for emitting a light beam; a split element for splitting the light beam emitted from the light source into the signal beam and the reference beam; an angular variable element for changing an incident angle of the split reference beam to the optical information recording medium; a spatial light modulator for adding the information signal to be recorded to the split signal beam; an objective lens which irradiates the optical information recording medium with the signal beam to which the information signal is added; an image sensor that detects a diffracted beam generated from a region to be reproduced through the objective lens, and forms the diffracted beam into a reproduction signal when irradiating the optical information recording medium with the reference beam; and a photodetector different from the image sensor, which detects the diffracted beam generated from a plurality of recorded regions in the optical information recording medium when irradiating the optical information recording medium with the reference beam, wherein an angular error signal for controlling the angular variable element is generated using a signal detected by the photodetector.