| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a forgery preventing sheet for a merchandise coupon, a stock certificate and various cards, the authenticity determination for which is easy and sure, but is hard to be forged. SOLUTION: The merchandize coupon 1 being the forgery preventing sheet is provided with markings having various sizes, formed by inclined through holes 5a, 6a arranged at intervals on the coupon 1, in which laser beams 8a, 10a are radially applied to the merchandize coupon 1 at a different angle using a vertically movable variable mirrors 9, 9a and at various heights.</p> |
