| 摘要 |
1510832 Credit cards and the like GAO GES FUR AUTOMATION UND ORGANISATION mbH 24 July 1975 [26 July 1974] 30997/75 Heading B6A Information is printed on the surface of a security document provided with a homogeneous protective film either overlying or underlying the print, the reflectance or fluorescent properties of the surface, print and film being such that damage to the film is optically detectable. In a first embodiment, the film is of UV absorptive material and, when viewed under UV light, the bright surface of the underlying paper document shows through any damaged area of the film. In a second embodiment, the film is black and has high reflectance in the IR region. The print overlies the film is black and has low reflectance in the IR region. The document must therefore be read under IR radiation, whilst any damage to the film exposes bright areas of the paper document when viewed in the visible spectral region. In a third embodiment, the film is of daylight luminous paint underlying the print and damaged areas appear dark under UV light. In a fourth embodiment, the film is coloured or transparent fluorescent paint. In a fifth embodiment, a fluorescent substance is coated on to the paper surface before a UV absorptive film is applied either over or under the print. Damage shows bright under UV light. The information may be binary coding stripes across a fluorescent film strip. Damaged areas may be detected by a verifying device including a suitable irradiation source, filters, lenses and radiation detectors. |
