METHOD OF MARKING A DOCUMENT OR ITEM; METHOD AND DEVICE FOR IDENTIFYING THE MARKED DOCUMENT OR ITEM; USE OF CIRCULAR POLARIZING PARTICLES

摘要

Optical identification and/or authentication of a document or item with the help of a marking comprising a random distribution of circular polarized light reflecting particles, the marking being applied to the document or item through an ink, and the reading device exploiting circular polarization to discriminate the flakes from the background.