Patent ID: 9196107
Filing Date: 2015-11-24
Classification: B42D,G01N,G07D

Abstract:
1. A method comprising preparing or labeling a security document, article, or element with a combination comprising at least two types of nanoparticles of material presenting Raman effect, wherein: each of the at least two types of nanoparticles is in a dispersed state or is in an agglomeration state forming agglomerates between 2 and 500 nanoparticles where said agglomerates have a size less than 2 microns; the at least two types of nanoparticles differ from each other in their chemical composition, in their crystal structure, in their shape, in their size and/or in their dispersed or agglomeration state; and when the at least two types of nanoparticles differ in their dispersed or agglomerated state, one type of nanoparticles is in a dispersed state and at least one other type of nanoparticles is in an agglomeration state forming agglomerates of between 2 and 500 nanoparticles, or the at least two types of particles form are in an agglomeration state forming agglomerates containing different numbers of nanoparticles between 2 and 500 nanoparticles.