Electronic security tag useful in electronic article indentification and surveillance system
First Claim
1. A resonant tag circuit useful as an electronic security device, comprising a layered planar structure having a dielectric substrate with first and second opposing principal surfaces;
- a resonant circuit capable of resonating at at least one predetermined frequency and comprising a pattern of conductive material carried on each of the opposing surfaces of the dielectric substrate, said resonant circuit including at least one activation or deactivation point for creating a short circuit or open circuit in the resonant circuit upon exposure of the resonant circuit to an activation or deactivation field at a predetermined energy level; and
a semiconductive antistatic material having an ionizable salt dissolved therein, said antistatic material being applied on a portion of one surface of the dielectric substrate to provide a semiconductive bridge across at least one activation or deactivation point in the resonant circuit by contacting conductive material in the circuit on both sides of the point.
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Accused Products
Abstract
A resonant tag circuit useful as an electronic security device includes a layered planar structure having a dielectric substrate, a resonant circuit carried on both sides of the dielectric substrate and a semiconductive material having an ionizable salt dissolved therein. The semiconductor material provides a sermiconductive bridge across an activation or deactivation point in the circuit and connects the conductive circuit on both sides of the activation or deactivation point. The resonant tag circuit of this invention is stabilized against premature operation of the activation or deactivation point from electrostatic discharge.
128 Citations
27 Claims
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1. A resonant tag circuit useful as an electronic security device, comprising a layered planar structure having a dielectric substrate with first and second opposing principal surfaces;
- a resonant circuit capable of resonating at at least one predetermined frequency and comprising a pattern of conductive material carried on each of the opposing surfaces of the dielectric substrate, said resonant circuit including at least one activation or deactivation point for creating a short circuit or open circuit in the resonant circuit upon exposure of the resonant circuit to an activation or deactivation field at a predetermined energy level; and
a semiconductive antistatic material having an ionizable salt dissolved therein, said antistatic material being applied on a portion of one surface of the dielectric substrate to provide a semiconductive bridge across at least one activation or deactivation point in the resonant circuit by contacting conductive material in the circuit on both sides of the point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- a resonant circuit capable of resonating at at least one predetermined frequency and comprising a pattern of conductive material carried on each of the opposing surfaces of the dielectric substrate, said resonant circuit including at least one activation or deactivation point for creating a short circuit or open circuit in the resonant circuit upon exposure of the resonant circuit to an activation or deactivation field at a predetermined energy level; and
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15. A resonant tag circuit useful as an electronic security device, comprising a layered planar structure having a dielectric substrate with first and second opposing principal surfaces;
- a resonant circuit capable of resonating at at least one predetermined frequency and comprising a pattern of conductive material carried on each of the opposing surfaces of the dielectric substrate, said resonant circuit including a parallel plate capacitor having a first plate on the first surface and a second plate on the second surface, said second plate being electrically connected through the dielectric substrate to a conductive member located on said first surface in proximity to, but not contacting, the first plate; and
a semiconductive antistatic material containing an ionizable salt that overlays and contacts at least a portion of the first plate and at least a portion of the conductive member to provide a semiconductive bridge between said first plate and said conductive member. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
- a resonant circuit capable of resonating at at least one predetermined frequency and comprising a pattern of conductive material carried on each of the opposing surfaces of the dielectric substrate, said resonant circuit including a parallel plate capacitor having a first plate on the first surface and a second plate on the second surface, said second plate being electrically connected through the dielectric substrate to a conductive member located on said first surface in proximity to, but not contacting, the first plate; and
Specification