Patent ID: 7859974

Claim:
An optical information recording/reproducing apparatus comprising: a first light source that emits an irradiation beam for recording or reproduction; a second light source that emits a servo irradiation beam; a converter that converts the irradiation beam into an information beam carrying information; an optical mechanism that collects the information beam and a reference beam to an optical information recording medium that has a diffraction grating and an information recording layer capable of recording the information as hologram, by using interference fringes produced due to interference between the information beam and the reference beam, and that guides the servo irradiation beam into the diffraction grating and causes the servo irradiation beam to be transmitted through the diffraction grating; a photodetector that detects a diffracted beam diffracted by the diffraction grating and transmitted therethrough; a drive unit that drives the optical mechanism or the optical information recording medium; and an adjusting unit that controls the drive unit to adjust a position or an angle between the optical information recording medium and the optical mechanism, based on the intensity of the diffracted beam detected by the photodetector.