| 摘要 |
PROBLEM TO BE SOLVED: To provide a novel hologram sheet that is a hologram sheet using a relief hologram, in which a stable change, such as in color tone, occurs in a hologram reproduced image if heat treatment is applied for improving the authenticity.SOLUTION: In a hologram sheet, a thermochromic thin film layer is provided on a hologram formation layer. A change in reproduction direction and color tone of a hologram reproduced image before and after application of predetermined heat treatment by heat treatment means can be visually checked, for improving the forgery preventiveness. |
