Banknote security mark - uses 2 or more substances which are fluorescent under ultraviolet of different wavelengths

摘要

Security marking for paper and film with a smooth surface, esp. bank notes, is invisible in daylight but can be seen when irradiated by an energy source using at least two substances which are fluorescent in rays of different wavelengths. One of the substances is fluorescent at longwave ultra-violet of 366nm, while the other is fluorescent in a shortwave ultra-violet at 254nm. One substance is fluorescent or absorbent under X-rays. The substance to fluoresce under shortwave ultra-violet of 254nm is an orange-red fluorescent of yttrium europium oxide or a compsn. Y2O3Eu. The substances for the fluorescent marking are mixed together in a homogenous blend of larger particles or units as a paint or coating which can be printed. The bonding and other agents added to the material do not or hardly absorb ultra-violet rays of 254nm. The surface of the paper, etc., is wholly covered with a neutral print which closely matches the design of the security marking, in a screen where the security marking can be applied in register. The paper surface contains no matter which will fluoresce under longwave U.V. at 365nm. The closed housing (1) has a dividing wall (2) which leaves a gap at the bottom. An entry slit (3) allows the paper material (7) to be inserted to be viewed through a window (4). Two radiators (5,5a) deliver rays at different wavelengths at the paper, which can be removed (6) after testing. ADVANTAGE - The method prevents forgery and allows detection by the relatively simple appts. available for retail outlets and currency exchange kiosks.