| 摘要 |
PURPOSE:To obtain a multi-function optical card by providing optical recording parts on both front and rear surfaces of the card to make possible recording with high density or to provide the functions different on the front side and rear side. CONSTITUTION:The card consists, from one surface to the other, of a surface hardened layer 4, a protective layer 3, the optical recording part (the 1st record ing layer 2a, the 2nd recording layer 2b), an adhesive agent layer 5, the optical recording part (the 2nd recording layer 2b, the 1st recording layer 2a), a protec tive layer 3 and a surface hardened layer 4. The writing of the information to the thin metallic film layer of the layer 2b is executed by condensing and irradiating the energy of a laser beam having a prescribed wavelength by a lens on the thin film layer to evaporate or distribute unevenly the metal in the irradiated part thereby forming recording pits. The reading out of the infor mation is executed by condensing and irradiating the beam, etc. of the energy as low as not to melt the thin film layer by a lens onto the layers 2a, 2b from the layer 3 and detecting associatedly the intensity and phase change of the reflected light. |
