Diffusion controlled security tags
AssigneeWright State University
InventorPaul G. Seybold
Life of this patent
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Abstract
A diffusion-controlled security tag comprising a carrier containing a solution of a compound which changes color upon diffusion or evaporation of the solvent. Preferably the carrier is enveloped in a barrier film which controls the rate of diffusion/evaporation of the solvent from the carrier such that a change in the color of the carrier indicates undesirable storage or product tampering.
Claims25
A diffusion-controlled security tag comprising a carrier and a solution of a compound which changes color upon evaporation of the solvent forming said solution, said carrier being impregnated with said solution and being completely enclosed within a barrier film, said barrier film limiting the rate of diffusion of said solvent from said carrier such that a change in the color of said compound indicates that an object with which said tag is associated has been subjected to tampering or adverse storage time or temperature.
A method for monitoring the storage of a perishable item which comprises the steps of:
- associating a security tag with said item such that said tag is subjected to essentially the same storage conditions as said item, said tag comprising a carrier containing a solution which undergoes a color change upon evaporation of the solvent, and examining said tag for a color change which indicates that said tag has been subjected to tampering or adverse storage conditions.
A tamper-indicating, sealed container comprising a carrier therein and a solution of a compound which changes color upon evaporation of the solvent, said carrier being impregnated or otherwise filled with said solution, and said sealed container maintaining vapor pressure of said solvent such that when the seal on said container has been broken evaporation of the solvent is accompanied by a change in the color of said carrier.
A diffusion-controlled security tag comprising a carrier and a microencapsulated solution of a compound which changes color upon evaporation of the solvent forming said solution, said solution being microencapsulated in a barrier film which limits the rate of diffusion of said solvent from said solution such that a change in the color of said compound indicates that an object with which said tag is associated has been subjected to tampering or adverse storage time or temperature.
Dependencies are inferred from the claim text.