| 摘要 |
PROBLEM TO BE SOLVED: To provide an information card of high reliability with high security because the place of a bar code is not known from the surface by composing the bar code by arranging a fine pattern of a film made of a material whose acoustic impedance is different from that of an information card provided to part of a card base material. SOLUTION: A card base material 1 is formed by sticking card base material pieces 1a and 1b made of a PET or the like and a bar code 3 for ultrasonic wave detection is buried between respective card base material pieces 1a and 1b. This bar code 3 is finely formed by a metal film such as aluminum or nickel whose acoustic impedance is largely different from that of the card base material 1. In this way, it is possible to mount a large amount of information by arranging a film fine pattern by a material which has an acoustic impedance different from that of the card base material 1 in the bar code 3. Thus, also, the bar code 3 does not reveal itself on the surface of an information card 10 and it is possible to have constitution in which an installation place is not known from outside. |
