Patent ID: 8824032
Filing Date: 2014-09-02
Classification: B42D,G02B,G06K,Y10T

Abstract:
1. A security device comprising: a uniform zero-order diffractive microstructure to display a colour change on tilting or rotating the uniform zero-order diffractive microstructure, the uniform zero-order diffractive microstructure being buried within a substrate and having an index of refraction higher than an index of refraction of the substrate; and a further structure comprising a plurality of macroscopic optical structures in a form of at least one of a sawtooth, an asymmetric sinus, prisms, or rod-like lenses formed in a region of the uniform zero-order diffractive microstructure, wherein the further structure is configured such that the plurality of macroscopic optical structures modifies the colour displayed by the uniform zero-order diffractive microstructure.