Surface deactivateable tag

Abstract

A security tag used with an electronic security system comprises a dielectric substrate having first and second opposite principal surfaces and a resonant circuit capable of resonating at a frequency within a detection frequency range. The resonant circuit is formed, in part, by a first conductive area on the first substrate surface and a second conductive area on the second substrate surface, the two conductive areas being generally aligned with one another to establish a capacitor with the substrate therebetween forming the capacitor dielectric. A third conductive area is provided on one of the principal substrate surfaces proximate to but not electrically connected to one of the two capacitor plates. The third conductive area is electrically connected to the other capacitor plate. A portion of the third conductive area is spaced from a portion of the one capacitor plate by a predetermined minimum distance whereby upon the application of electromagnetic energy to the tag at a frequency generally corresponding to the resonant frequency of the resonant circuit and at or above a predetermined minimum energy level, an electric arc extends between the spaced portions of the third conductive area and the one capacitor plate creating a persistent conductive bridge which connects the two plates of the capacitor in a short circuit.