US Patent 9274258 Thin-layer element having an interference layer structure

The present invention relates to a thin-film element (30) having an interference layer structure for security papers, value documents and the like, having at least two semitransparent absorber layers (34, 38) and at least one dielectric spacing layer (36) arranged between the at least two absorber layers. According to the present invention, it is provided that the two absorber layers (34, 38) are each formed from a material having a complex refractive index N whose real part n and imaginary part k differ at least in a portion of the visible spectral range by a factor of 5 or more.