| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a forgery-proof medium which has at least, a light absorption layer and an optical interference layer which allows a hue to be differently observed by changing a visual angle, overlying an infrared reflective base material, and an unlawfulness determination method using the forgery-proof medium, and especially, the forgery-proof medium which has the light absorption layer representing a combination of pattern layers, each being formed of at least, three different black inks with different light absorbencies in an infrared light region respectively, and contains specified inherent information in an invisible state, and the unlawfulness judging method using this forgery-proof medium. <P>SOLUTION: At least the light absorption layer and the optical interference layer which allows the hue to be differently observed by changing the visual angle, are formed on the infrared reflective base material in the way that the relative positional relationship of the layers is found in the described order. In addition, the light absorption layer is represented by the combination of the pattern layers, each being formed of at least three different black inks with different light absorbencies in the infrared light region respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT |
