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Tamper resistant magnetic stripes

United States Patent

5,981,053
November 9, 1999
View the Complete Patent at the US Patent & Trademark Office
Sandia National Laboratories - Visit the Intellectual Property Management and Licensing Website
This invention relates to a magnetic stripe comprising a medium in which magnetized particles are suspended and in which the encoded information is recorded by actual physical rotation or alignment of the previously magnetized particles within the flux reversals of the stripe which are 180.degree. opposed in their magnetic polarity. The magnetized particles are suspended in a medium which is solid, or physically rigid, at ambient temperatures but which at moderately elevated temperatures, such as 40.degree. C., is thinable to a viscosity permissive of rotation of the particles therein under applications of moderate external magnetic field strengths within acceptable time limits.
Naylor; Richard Brian (Albuquerque, NM), Sharp; Donald J. (Albuquerque, NM)
Sandia Corporation (Albuquerque, NM)
08/ 132,078
October 5, 1993
The United States Government has rights in this invention pursuant to Contract No. DE-AC04-76DP00789 between the Department of Energy and Sandia National Laboratories.