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Security device

  • US 5,644,295 A
  • Filed: 09/05/1995
  • Issued: 07/01/1997
  • Est. Priority Date: 09/05/1994
  • Status: Expired due to Term
First Claim
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1. A security device for fixing to a surface to allow relative movement of the device and the surface to be detected, the device comprising:

  • a substrate having a fixing portion by which the device may be fixed to the surface;

    an adhesive layer for fixing the fixing portion to the surface; and

    circuit means defining a circuit between two locations on the device and having predetermined electrical characteristics, at least part of the circuit means being located between the substrate and the adhesive layer and having in a first region a greater adhesion with the substrate than with the adhesive layer and in a second region a greater adhesion with the adhesive layer than with the substrate so that when the device is fixed to the surface by said adhesive layer, relative movement of the substrate and the surface disrupts the circuit means by measurably changing said predetermined electrical characteristics.

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