Patent ID: 7907494

Claim:
A hologram information recording medium for performing recording thereon by irradiating the recording medium with signal light and reference light while varying a multi-parameter, and for reproducing recorded information therefrom by using reproduction light diffracted by the reference light while varying said multi-parameter, wherein the multi-parameter to reproduce the recorded information depends on temperature as the hologram information recording medium expands or contracts according to the temperature, wherein the hologram information recording medium comprises: a plurality of hologram information groups recorded by a different range of the multi-parameter in substantially the same area, each hologram information group including the same data such that at least one of the plurality of hologram information groups reproduces a target data element if the hologram information recording medium expands or contracts according to the temperature, and wherein, if the target data element of one of the plurality of hologram information groups is not reproducible due to a change in the temperature, another hologram information group provides a corresponding target data element which is reproducible at the changed temperature.