Authentication of articles having a polymeric film by measuring thickness of film or layer within film by white light interferometry and/or by birefringence

摘要

The present invention provides a method of authenticating the provenance of an article marked with a transparent polymer film comprising measuring the thickness of the film or of a layer within the film by white light interferometry and/or by birefringence. The polymer film may be a label applied to the article by an in mould labelling process.