OPTICAL DIFFRACTION STRUCTURE AND AUTHENTICATION PATTERN AS WELL AS THEIR FORMATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a light diffracting structure having a sensible parameter which can not be directly copied or reformed, a certification pattern and a certification label. SOLUTION: A light diffracting structure 10 within a certification pattern corresponding to a certification label 30 is used particularly for certification and protection of forgery to various treasurer. The light diffracting structure 10 has a characteristic parameter for generating a characteristically colored pattern. The characteristic parameter is defined at random by an anisotropic process during the formation of the diffracting structure without depending on the perfect management of a manufacturer. This prevents the copy or formation of a precise reproduction. A certification pattern 20 comprises a joint structure of a base layer 21 and a transparent overcoat layer 22, and the light diffracting structure 10 is contained in the observable critical surface between them. The characteristically colored certification pattern can be confirmed by a simple observation by naked eyes. This is an essential condition for confirmation in every place.