Pigments having a viewing angle dependent shift of color, method for producing said pigments, use of said pigments in security applications, coating composition comprising said pigments and a detecting device
AssigneeSicpa Holding SA
InventorsOlivier Rozumek, Edgar Müller
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Abstract
The invention describes luminescent optically variable pigments (OVP), methods for obtaining such pigments, as well as the use of such pigments as security elements in inks, coatings and articles. The luminescence centers are preferably incorporated into the dielectric material of the OVP's optical<i>Fabry-Perot</i> resonance cavity, allowing for the machine-discrimination of luminescent OVP from simple mixtures of luminescents and non-luminescent OVP.
Claims28
A pigment comprising an interference structure having at least two thin film layers of different materials, said pigment having a viewing angle dependent shift of color, wherein the interference structure has a light-transmitting dielectric layer which comprises at least one luminescent material.
Dependencies are inferred from the claim text.