| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a material such as cards capable of preventing forgery, easy and sure in discrimination for true or falsehood, and not restrained in terms of design. SOLUTION: By radiating a laser beam onto a transparent plastic made card base material 1 from its one side end face 1a directing toward the inner part, and setting a focus position to the inner part of the base material 1, a fine true mark 2 showing a true article is formed on the focus position by the laser beam. Depending on whether the true mark 2 exists inside the card base material or not, the true or falsehood can be discriminated, and on the other hand, since the forming of the true mark is defficult, the prevention of forgery becomes possible.</p> |
