Inductor-capacitor resonant circuits and improved methods of using same

• US 20020017993A1
• Filed: 09/10/2001
• Published: 02/14/2002
• Est. Priority Date: 01/02/1997
• Status: Active Grant

• Current Assignee: C W Over Solutions Incorporated
• Original Assignee: C W Over Solutions Incorporated
• Inventors: Blama, Michael J., Freeman, J. Steve
• Granted Patent: US 6,714,120 B2
• Time in Patent Office: Days
• US Class Current: 340/572.1
• CPC Class Codes: G06K 19/0672 with resonating marks
• CPC Class Codes: G06K 19/08 using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means
• CPC Class Codes: G06K 7/086 sensing passive circuit, e.g. resonant circuit transponders

Abstract

A tag which uses radio frequency waves transmitted from a scanning device in order to identify an item to which the tag is attached or with which the tag is associated. The tag includes a first insulating layer having a top surface and a bottom surface, and resonant circuits formed on the first insulating layer. Each of the resonant circuits are formed on one of the top surface and the bottom surface of the first insulating layer and have a resonant frequency associated therewith. Each of the resonant circuits include capacitance and inductance elements. The capacitance and inductance elements include an inwardly spiralled coil connected to an outwardly spiralled coil. The tag is associated with a binary number established by a pattern of ones and zeros depending on each circuits'"'"' resonance or nonresonance, respectively.

Claims

1. A tag which uses radio frequency waves transmitted from a scanning device in order to identify an item to which said tag is attached or with which said tag is associated, comprising:

a first insulating layer having a top surface and a bottom surface;

a plurality of resonant circuits formed on said first insulating layer, each of said plurality of resonant circuits formed on one of the top surface and the bottom surface of said first insulating layer and having a resonant frequency associated therewith, each of said plurality of resonant circuits including capacitance and inductance elements, said capacitance and inductance elements comprising an inwardly spiralled coil connected to an outwardly spiralled coil; and

wherein said tag is associated with a binary number established by a pattern of ones and zeros depending on each circuits'"'"' resonance or nonresonance, respectively.

2. The tag as in claim 1, wherein said capacitance element further includes a dielectric dot.

3. The tag as in claim 2, wherein said inductance element is made from a conductive material.

4. The tag as in claim 1, wherein said plurality of circuits are located on a surface of said tag at spaced intervals of a distance far enough apart so that adjacent circuits do not electronically interfere with each other.

5. The tag as in claim 4, wherein said tag associates a bit of information with each of said plurality of circuits on the surface of said tag.

6. The tag as in claim 5, wherein said tag is made of a nonconductive material.

7. The tag as in claim 6, wherein the nonconductive material of said tag is at least one of paper, glass and plastic.

8. The tag as in claim 5, wherein said pattern of binary ones and zeros is established by varying numbers and positions of circuits being left blank.

9. The tag as in claim 5, wherein said pattern of binary ones and zeros is established by disabling a circuit on said tag.

10. A tag which uses radio frequency waves transmitted from a scanning device in order to identify an item to which said tag is attached or with which said tag is associated, comprising:

a first insulating layer having a top surface and a bottom surface; and

a plurality of resonant circuits formed on said first insulating layer, each of said plurality of resonant circuits formed on one of the top surface and the bottom surface of said first insulating layer and having a resonant frequency associated therewith, each of said plurality of resonant circuits including capacitance and inductance elements, said capacitance and inductance elements comprising an inwardly spiralled coil connected to an outwardly spiralled coil.

11. A tag as in claim 10, wherein said tag is associated with a binary number established by a pattern of ones and zeros depending on each of said plurality of resonant circuits resonating, or not resonating, respectively.

12. A tag as in claim 10, wherein at least one of said plurality of resonant circuits is tuned by at least one of changing a mass of the capacitance and changing a length of the inductance.

13. A tag as in claim 10, wherein said tag is associated with a three-state system established by each of said plurality of resonant circuits resonating at a high quality level, resonating at a low quality level, or not resonating.

15. A resonant tag as in claim 14, wherein at least one of said plurality of resonant circuits is tuned by at least one of changing a mass of the single capacitor and changing a length of the single inductor coil.

16. A resonant tag as in claim 14, wherein said tag is associated with a three-state system established by each of said plurality of resonant circuits resonating at a high quality level, resonating at a low quality level, or not resonating.

17. A resonant tag as in claim 14, wherein said inductor coil includes first and second ends, and each of said first and second ends are connected to said capacitor.

19. The method as in claim 18, wherein said step of providing a radio frequency identification tag with a plurality of circuits is accomplished by etching said surface of said tag which has been coated with a layer of conductive material.

20. The method as in claim 18, wherein said step of providing a radio frequency identification tag with a plurality of circuits is accomplished by printing onto or pressing into said surface of said tag a conductive material.

14. A resonance tag including a plurality of resonant circuits each comprising a capacitor element, and a inductor element electrically connected to said capacitor element, and said capacitor element and said inductor element are disposed on a same surface of the resonance tag, and said capacitance and inductor elements comprising an inwardly spiralled coil connected to an outwardly spiralled coil.

18. A method of identifying an item to or with which a radio frequency identification tag is attached or associated, respectively, comprising the steps of:

providing said radio frequency identification tag having a plurality of resonant circuits formed on a first insulating layer, each of said plurality of resonant circuits formed on one of the top surface and the bottom surface of said first insulating layer and having a resonant frequency associated therewith, each of said plurality of resonant circuits including capacitance and inductance elements, said capacitance and inductance elements comprising an inwardly spiralled coil connected to an outwardly spiralled coil;

using a scanning device to interrogate said plurality of resonant circuits by transmitting varying radio frequency waves at which said plurality of resonant circuits may resonate to said radio frequency identification tag; and

interrogating said plurality of resonant circuits to establish a pattern of binary ones and zeros.

21. A system, comprising:

a resonance tag including a plurality of resonant circuits each comprising a single capacitor, a single inductor coil electrically connected to said single capacitor, and an insulating layer separating portions of said single capacitor and said single inductor coil that cross over from each other, and said single capacitor and said single inductor disposed on a same surface of the resonance tag, said single capacitor and said inductor coil comprising an inwardly spiralled coil connected to an outwardly spiralled coil; and

a scanning device configured to transmit radio frequency waves to said resonance tag and to said plurality of resonant circuits at varying frequencies which said plurality of resonant circuits may resonate to identify an item to which said resonance tag is attached or with which said resonance tag is associated.