Abstract:
A security system and method for detecting unauthorized removal of items at an exit from a control area. The system includes labels applied to the items, the labels including a plurality of circuit elements, each circuit element being responsive to a different frequency. The labels are modifiable from an initial condition in which all of the circuit elements are actively responsive to their respective frequencies, to a live condition in which at least one but not all of the circuit elements is deactivated and rendered non-responsive to its respective frequency. The labels are also modifiable from the live condition to a dormant condition in which at least one additional circuit element is deactivated and rendered non-responsive to its respective frequency. Different frequencies are generated at the exit of the monitored area, to which said plurality of circuit elements are responsive so as to induce frequency responses by the circuit elements which remain activated. A control unit is responsive to the frequency responses generated by labels in the live condition for generating a control signal.
Abstract:
An optical device (10) receives incident light (28) having a minimum wavelength, and produces resultant light containing an optical image (32). The device (10) includes a first material (20) having a first index of refraction and a surface (18) embossed with an optical interference pattern (16) and a second material (22) having a second index of refraction deposited onto the embossed surface (18) of the first material (20). The depth of deposition is at least equal to three quarters of the minimum wavelength component of the incident light within the second material.
Abstract:
A frangible label which includes a plurality of integrally joined layers deposited successively on a removable carrier film. One or more of the layers are electrically conductive and configured to define an electrical circuit. The label is transferrable from the carrier film onto a receiving surface and is otherwise inseparable from the carrier film without attendant disruption of the circuit. In an alternative embodiment, the label includes an adhesive layer for applying the label to a substrate, such that the plurality of integrally joined layers including the electrical circuit are transferrable to the receiving surface and are otherwise inseparable from the carrier film without destruction of the electrical circuit.
Abstract:
An optical device (10) receives incident light (28) having a minimum wavelength, and produces resultant light containing an optical image (32). The device (10) includes a first material (20) having a first index of refraction and a surface (18) embossed with an optical interference pattern (16) and a second material (22) having a second index of refraction deposited onto the embossed surface (18) of the first material (20). The depth of deposition is at least equal to three quarters of the minimum wavelength component of the incident light within the second material.