Tamper-evident structures

A kit of parts capable of forming a tamper-evident structure, said kit comprising:

• a laminate capable of generating a substantially non-dichroic colour by a light interference and absorption phenomenon, consisting of a layer of a metal of medium light reflectivity and a layer of a metal oxide, said layer of metal oxide having been formed by anodization in the presence of fluorine ions, at least in areas of said laminate where a colour change is desired;
• and
• a flexible strip of transparent or translucent material suitable for facilitating the peeling apart of said laminate, said strip being capable of being adhered to said laminate with a strength of attachment that is greater than the strength of attachment of said layers in said desired areas;
• whereby said flexible strip may be adhered to said laminate and caused to peel apart said laminate resulting in loss of said generated colour, at least in said desired areas, and whereupon re-attachment of said layers fails to re-generate said colour.

A tamper-evident structure which comprises:

• a laminate capable of generating a substantially non-dichroic colour by a light interference and adsorption phenomenon, consisting of a layer of a metal of medium light reflectivity, a first layer of a metal oxide, a translucent layer of a metal of medium light reflectivity and a second layer of a metal oxide, said layers being arranged in the stated order and said second layer of metal oxide having been formed by anodization in the presence of fluorine ions, at least in areas of the laminate where a colour change is desired;
• and
• an overlying flexible strip of transparent or translucent material suitable for the peeling apart of said laminate, said strip having a strength of attachment to said laminate that is greater than the strength of attachment of said second layer of metal oxide to said translucent metal layer, at least in said desired areas, but less than the strength of attachment between other layers of said laminate;
• whereby peeling apart of said second metal oxide layer and said translucent metal layer results in loss of said generated colour and re-attachment of said layers fails to regenerate said colours.