| 摘要 |
PURPOSE:To facilitate reading, and to reduce a read error, by providing a light absorbing layer on the rear plane of a metallic thin film layer, and specifying the ratio of light reflectance between a part where the metallic thin film layer exists, and a part where no metallic thin film layer exists. CONSTITUTION:A metallic thin film layer 3 in which an optical information pattern 2 is written, and a light absorbing layer 4 that the light absorbing material is coupled by an appropriate binder, are formed on the rear plane of a protection layer 1, and the layer 4 is stuck on a card base material 7 through a sticking agent layer 51. In the metallic thin film layer 3, the reflectance of the surface plane of an evaporated aluminum, for example, is about 80%, and the reflectance of an ordinary sticking agent layer, or the card base material is about 10%. By providing the light absorbing layer 4 on the rear plane of the metallic thin film layer 3, the reflectance of the part where no metallic thin film layer 3 exists, is lowered by around 5%, and the ratio of 10:1 or more of the light reflectance of the part where the metallic thin film layer 3 exists, to that of the part where no layer 3 exists, can be easily obtained. In this way, it is possible to use a simplified and inexpensive card reader, and to facilitate the reading if a working card reader is used, and to reduce remarkably the read error. |
