| 摘要 |
PROBLEM TO BE SOLVED: To enable the high-sensitivity reading out of the information which is to be kept confidential and is recorded on a second recording layer by providing the medium with a substrate, a first recording layer and a protective layer, providing the medium with a second recording layer in a manner as to bring this layer in contact with the transparent substrate or the transparent protective layer and forming a thin- film optical waveguide in contact with the second recording layer. SOLUTION: The thin-film optical waveguide 12 is formed in contact with the second recording layer 6 facing the protective layer 4. The second recording layer 6 formed by the prescribed hologram pattern is concealed by a first concealing layer 71 and a second concealing layer 72 and the presence of the information of the second recording layer 6 is not admitted when viewed from the substrate 1 and the protective layer 4 and thin-film optical waveguide 12 side. The information is, however, identifiable only when the second recording layer 6 is viewed through the transparent protective layer 4 and the thin-film optical waveguide 12 from the flank. A semiconductor laser is connected in proximity to the thin-film optical waveguide 12. As a result, the reading of the output pattern from the semiconductor laser is made possible at the flank of an optical card as the optical information recording medium by using a photodetector. |
