BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a conceptual illustration of a coaxial optical system used in a holographic recording apparatus using a coaxial method;
FIG. 2 illustrates examples of a signal light beam pattern and a reference light beam pattern displayed on a spatial light modulator;
FIG. 3 is a conceptual illustration of a coaxial optical system used in a holographic reconstruction apparatus using the coaxial method;
FIG. 4 is a schematic illustration of a hologram recording and reconstruction apparatus including an optical unit as a main part;
FIG. 5 is a schematic illustration of the cross-sectional structure of a holographic recording medium;
FIGS. 6A-6C illustrate examples of reconstructed images displayed on an image sensor when an all-white reference light beam pattern is used;
FIGS. 7A and 7B are schematic illustrations of encrypting steps;
FIGS. 8A and 8B are schematic illustrations of decrypting steps;
FIGS. 9A-9E illustrate signal light beam patterns for encryption;
FIG. 10 is a diagram in which pages to be encrypted are spatially distributed;
FIGS. 11A-11D illustrate reconstructed images generated on the image sensor when a hologram recorded without encryption is reconstructed using a reference light beam that is the same as the one used at a recording time, a reference light beam that has no correlation with the one used at a recording time, and an all-white reference light beam; and
FIG. 12A1-12C2 illustrate reconstructed images generated on the image sensor when a hologram recorded with encryption is reconstructed using a reference light beam that is the same as the one used at a recording time, a reference light beam that has no correlation with the one used at a recording time, and an all-white reference light beam.
Patent Application
20070211320
