| 摘要 |
<p>PCT No. PCT/DE81/00078 Sec. 371 Date Oct. 23, 1981 Sec. 102(e) Date Oct. 23, 1981 PCT Filed May 29, 1981 PCT Pub. No. WO81/03507 PCT Pub. Date Dec. 10, 1981.Security papers with luminescing authenticity characteristics built in or printed thereon which absorb in the visible region of the optical spectrum but in the infrared have a transparent region in which the luminophore also emits. By the absorption in the visible undesired parasitic emissions are suppressed which would make the luminophore visually evident on corresponding excitation. For testing the authenticity of the document the emission is investigated in the infrared. Suitable luminophores are rare earth metal luminophores in suitable host lattices, particularly in ferrite lattices or garnet lattices, which contain transition metal ions as absorbing elements.</p> |
