OPTICAL VARIABLE ELEMENT

摘要

(57) The invention relates to an optical variable element of visible black colour and it will be applicable as a security feature to certify the authenticity and the uniqueness of documents, banknotes and trademarks by applying on a sticker, or directly on the surface of the protected object. The proposed variable optical element of visible black colour contains a transparent diffraction layer, consisting of at least two superposed in different directions (angular shifted) diffraction patterns, and according to the invention it also includes an optical transformation layer (6), while the diffraction layer (5) configuration consists of two-dimensional shaped pyramids (9) with a raster distance (r), where the pyramids are placed on, within the scope of 0,2 um - 0,45 μm.