Patent ID: 9739597
Date: 2017-08-22
CPC Classifications: G01B,G01N

Claim:
1. A method of authenticating an object comprising a multilayer polymer film comprising a layer of biaxially oriented polypropylene (BOPP), wherein the method comprises the steps of: measuring the thickness of a core layer of said multilayer polymer film in the object by white light interferometry and obtaining a thickness measurement value therefrom; comparing the thickness measurement value obtained in said measurement step with a predefined thickness value indicative of a genuine object comprising the film; and authenticating the object by determining if said polymer film is equivalent or non-equivalent to a polymer film in a genuine object based upon the extent to which the comparison of the thickness measurement value obtained in said measuring step and the predefined thickness value is indicative of a genuine object comprising the film, wherein the film is made by a bubble or stenter process.