| 摘要 |
PROBLEM TO BE SOLVED: To read and recognize a remaining hologram normally, when information is recorded by destroying a hologram. SOLUTION: Data CGHs 11-1, 11-2, 11-4, and 11-5, representing information are arrayed in two dimensions of X and Y directions of a card 10 and positioning CGHs 11-3 for positioning the data CGHs 11-1, 11-2, 11-4, and 11-5 in the X direction and reading them are formed in the X direction and the diffraction angles and diffraction directions of the data CGHs 11-1, 11-2, 11-4, and 11-5 arrayed in the Y direction, and the positioning CGHs 11-3 are determined so that respective diffraction images are projected on an image pickup surface at the same time. |
