Patent ID: 7085025

Claim:
An optical information reproducing apparatus for reproducing information utilizing holography from an optical information recording medium having reflecting layer and information recording layer in which the information is recorded in the form of an interference pattern as a result of interference between information light carrying two dimensional digital pattern information and reference light for recording having a spatial modulation, the apparatus comprising: an input means for inputting individual information that is unique to an individual; a reproduction reference light generation means including modulation means for spatially modulating the light based on the individual information, for generating reference light for reproduction, the modulation means spatially modulating the reference light for reproduction in the same manner in which the reference light for recording was modulated when the information was recorded in the form of an interference pattern as a result of using the reflecting layer as a reference plane to generate interference between the information light and the reference light for recording; a reproducing optical system, for illuminating the information recording layer with the reference light for reproduction on a same side of the information recording layer that is illuminated with the information light and the reference light for recording and for collecting reproduction light on the same side of the information recording layer that is illuminated with the reference light for reproduction; and a detection means for detecting the reproduction light collected by the reproducing optical system, wherein the reproduction optical system projects the reference light for reproduction and collects the reproduction light such that an optical axis of the reference light for reproduction and an optical axis of the reproduction light are located on a same line.