Method of making tamper-evident structures

Claim 1

A method of forming a tamper evident structure, which comprises: forming a laminate capable of generating a substantially non-dichroic color by a light interference and absorption phenomenon by providing a layer of a metal of medium light reflectivity, anodizing a surface of said metal to form a film of an oxide of said metal on said surface, depositing a translucent layer of a metal of medium light reflectivity on a surface of said film by a vapour deposition technique, and anodizing a surface of said translucent layer to form a film of an oxide of said metal forming said translucent layer, said anodization of said translucent metal layer being carried out in presence of fluorine ions, at least in limited areas of said surface of said translucent metal layer, to make said film of an oxide of the metal of said translucent layer detachable from said translucent layer at least in said limited areas; and adhering a flexible strip of transparent or translucent material over said laminate in such a manner that the strength of attachment of the flexible strip to the laminate exceeds the adhesive strength between the film of an oxide of the metal of said translucent layer and the translucent metal layer, at least in said limited areas.

Claim 2

A method of forming a tamper evident structure, which comprises: forming a laminate capable of generating a substantially non-dichroic color by a light interference and absorption phenomenon by providing a layer of a metal of medium light reflectivity, anodizing a surface of said metal to form a film of an oxide of said metal on said surface, depositing a translucent layer of a metal of medium light reflectivity on a surface of said film by a vapour deposition technique, and anodizing a surface of said translucent layer to form a film of an oxide of said metal forming said translucent layer, said anodization of said translucent metal layer being carried out in presence of fluorine ions, at least in limited areas of said surface of said translucent metal layer, to make said film of an oxide of the metal of said translucent layer detachable from said translucent layer at least in said limited areas; and adhering a flexible strip of transparent or translucent material over said laminate in such a manner that the strength of attachment of the flexible strip to the laminate exceeds the adhesive strength between the film of an oxide of the metal of said translucent layer and the translucent metal layer, at least in said limited areas.