Patent ID: 7554893

Claim:
A recording/reproducing apparatus for an optical recording medium, comprising: a reference beam irradiator for irradiating an optical recording medium on which information is recorded by holography with a reference beam to generate a reproduction beam; a two-dimensional image pickup device capable of being partially read, which receives the reproduction beam; a partial reading controller for controlling partial reading of information on the two-dimensional image pickup device; an information processor for performing a predetermined process by using the information to be partially read; and a spatial light modulator for generating an object beam corresponding to two-dimensional data in which information to be partially read is arranged in correspondence with a partial reading characteristic of the two-dimensional image pickup device, wherein the spatial light modulator is provided with sectors and the information to be partially read is arranged therein on a block unit basis, the spatial light modulator being provided with a plurality of position detection markers as one of the information to be partially read and arranged at corner portions and center portions of sides of the spatial light modulator, and the sectors being arranged in a matrix at a center portion of the spatial light modulator.