Method and apparatus for deactivating an EAS device
First Claim
1. An EAS device deactivator comprising:
- a) an electrical coil;
b) a capacitor in electrical series with said coil;
c) means for varying the frequency of the current driving said coil and capacitor;
d) means for monitoring said coil and capacitor; and
e) means for adjusting said frequency of said driving current based upon the measurements provided by said means for monitoring.
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Accused Products
Abstract
A deactivator for deactivating label-style EAS devices is claimed. The preferred embodiment, of which, employs a microprocessor unit to control two transceiver coils, and a deactivation coil in series with a capacitor. The two transceiver coils are essentially two flat figure eights arranged concentrically but rotated through some angle with respect to each other. The transceiver coils are operated alternatively, first transmitting an interrogation signal and then listening for a response. When an EAS device is detected, the microprocessor unit drives the capacitor and deactivation coil at the system'"'"'s resonant frequency to generate a high amplitude magnetic field then shifts the frequency of the driving current away from the resonant frequency to attenuate the magnetic field. A field sensor or current sensor provides feedback to the microprocessor to determine the resonant frequency of the system during a frequency sweep.
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Citations
14 Claims
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1. An EAS device deactivator comprising:
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a) an electrical coil;
b) a capacitor in electrical series with said coil;
c) means for varying the frequency of the current driving said coil and capacitor;
d) means for monitoring said coil and capacitor; and
e) means for adjusting said frequency of said driving current based upon the measurements provided by said means for monitoring. - View Dependent Claims (2, 3, 4, 5)
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6. A method of deactivating an EAS device comprising:
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a) driving a capacitor and coil system with current at the resonant frequency of said system, and b) shifting the frequency of the driving current away from said resonant frequency. - View Dependent Claims (7, 8)
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9. An EAS device deactivator comprising:
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a) an electrical coil;
b) a capacitor in electrical series with said coil;
c) means for varying the frequency of the current driving said coil and capacitor;
d) means for monitoring said coil and capacitor;
e) means for adjusting said frequency of said driving current based upon the measurements provided by said means for monitoring, and f) means for detecting an EAS device brought into proximity with said deactivator. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification