Permanently destructible resonant circuit with non-self-healing capacitor
AssigneeCheckpoint Systems, Inc.
InventorsSeth Strauser, Charles Iacono, Lawrence Appalucci
Life of this patent
Estimating the term…
Abstract
A resonant circuit for use with a radio-wave detection system for the prevention of shoplifting or the like which has a coil and capacitor circuit whereby the circuit is permanently destroyed when the tag is exposed to a radio signal that causes a voltage across the capacitor that exceeds the breakdown voltage of the capacitor. The capacitor comprises a dielectric that does not exhibit self-healing. Such dielectrics include ceramics, metal oxides and minerals.
Claims19
A resonant circuit which resonates with a radio wave within a predetermined resonant frequency range, comprising:
- an inductor;
- and
- a capacitor having a predetermined dielectric breakdown voltage;
- wherein said inductor and capacitor form an LC circuit and wherein said resonant circuit is permanently disabled by inducing a voltage to said capacitor that exceeds said predetermined breakdown voltage;
- and
- wherein said capacitor comprises a dielectric made from one of the group consisting of:
- a ceramic, a metal oxide, a mineral.
A resonant tag comprising:
- a substrate having a first principal surface;
- a resonant circuit which resonates with a radio wave within a predetermined resonant frequency range, the resonant circuit comprising an inductor formed on said first principal surface of said substrate;
- said inductor connected in series with a capacitor having a predetermined breakdown voltage;
- wherein said resonant circuit is permanently disabled by applying an induced voltage to said capacitor that exceeds said predetermined breakdown voltage;
- and
- wherein said capacitor comprises a dielectric made from one of the group consisting of:
- a ceramic, a metal oxide, a mineral.
A circuit element adapted for use in a resonant circuit comprising:
- a strap having two electrically conductive ends wherein said electrically conductive ends are connected to each other by a dielectric material forming a capacitor having a predetermined breakdown voltage and wherein said dielectric material is selected from the group consisting of a ceramic, a metal oxide, and a mineral.
Dependencies are inferred from the claim text.