| 简介 |
The invention concerns a printed valuable document with at least one authentication feature in the form of a luminescent substance based on a host lattice doped with at least two rare earth metals. The host lattice largely absorbs in the visible region of the spectrum, is excitable in large parts of the visible region of the spectrum and transparent at least in partial areas of the IR spectral region. The luminescent substance is present in the volume of the valuable document in such a concentration that the characteristics of the valuable document just remain unimpaired. The rare earth metals concerned are thulium and holmium. |
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