| 摘要 |
PROBLEM TO BE SOLVED: To provide a security characteristic which can be attached to every possible carrier, such as a document, a bank note, an I.D. card and a plastic card and whose information included in it can not be recognized simply by being seen. SOLUTION: This optical authentication characteristic is for being attached to an optical carrier such as a document, and this method is for reading an authentication characteristic. A phase profile is modulated by light 3 and 4 made incident on a security characteristic with the aid of the security characteristic. The modulated phase profile is converted into amplitude information capable of being seen with eyes by, e.g. a phase difference method and a schlieren method or a means such as an interference device. In more detail, the security characteristic is composed of a hologram attached to a carrier, and object light having the modulated phase profile is restored by light made incident on the hologram. |
