| 摘要 |
<p>The invention relates to a security element for the protection of valuable objects. Said element comprises a first light-polarising layer (66) consisting of a cholesteric liquid-crystalline material, said layer selectively reflecting light with a predetermined circular polarisation and selectively reflecting light of a first wavelength range in a first reflection direction and light of a second wavelength range in a second, different reflection direction, a second light-polarising layer (68), which selectively reflects light with a counter-rotating polarisation to that of the predetermined circular polarisation and which selectively reflects light of the first or second wavelength range in the first or second reflection direction. At least some parts of the element also comprise a luminescent layer (64), on which the first and second light-polarising layer (66, 68) are located one above the other. The luminescent layer (64) emits light in the first and/or second wavelength range after being excited by excitation radiation (70) that lies outside the visible spectral range.</p> |
