RF identification tag configurations and assemblies

• US 5,604,485 A
• Filed: 04/21/1993
• Issued: 02/18/1997
• Est. Priority Date: 04/21/1993
• Status: Expired due to Fees

• Current Assignee: HID Corporation (Assa Abloy AB)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Ghaem, Sanjar, Lauro, George L., Istvan, Rudyard L.
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): Lee, Benjamin C.
• Application Number:
  US08/049,804
• Time in Patent Office: 1,399 Days
• Field of Search: 340/572, 340/568, 340/825.21, 340/825.34, 340/825.54, 156/247, 235/492
• US Class Current: 340/572.5
• CPC Class Codes: G06K 19/0672 with resonating marks
• CPC Class Codes: G08B 13/2414 using inductive tags
• CPC Class Codes: G08B 13/2417 having a radio frequency identification chip
• CPC Class Codes: G08B 13/2434 Tag housing and attachment details
• CPC Class Codes: G08B 13/2437 Tag layered structure, processes for making layered tags
• CPC Class Codes: G08B 13/2448 Tag with at least dual detection means, e.g. combined inductive and ferromagnetic tags, dual frequencies within a single technology, tampering detection or signalling means on the tag

Abstract

An RF tag (10) includes a plurality of RF resonant circuits (14, 18, 22) which are disposed in a three-dimensional array within a body (30) of solid material. Selected ones of the RF resonant circuits are coated with a conductive ink (36) for programming the RF tag. Non-planar RF resonant circuits (40, 50) provide enhanced directivity. The RF resonant circuits (14, 40, 50) are disposed within an elongated body (72, 82, 94) in spaced apart and substantially axially aligned relation to provide elongated RF tag configurations. An RF tag assembly (110) includes attachment mechanisms (116, 118) for attaching an RF tag (128) to a carrier. A dual mode RF tag assembly (140) is also provided which includes a passive RF circuit (144) and an active RF circuit (142).

Claims

1. An RF tag comprising a plurality of RF resonant circuits, each of said RF resonant circuits comprising a conductive portion which provides an inductance that determines an electrical resonant frequency for said resonant circuit, said RF resonant circuits being spaced apart and disposed in a three-dimensional array of said RF resonant circuits.

2. An RF tag as defined in claim 1 wherein each said RF resonant circuit includes a conductive coil, said conductive coil being substantially planar in configuration.

3. An RF tag as defined in claim 1 further including a body of solid material, said body having a length dimension, a width dimension, and a height dimension, and wherein said plurality of RF resonant circuits are disposed within said body in said three-dimensional array.

4. An RF tag as defined in claim 1 wherein each of said RF resonant circuits having at least one conductive coil being substantially planar in configuration with at least some of said RF resonant circuits having their coils positioned in different planes than any planar coils of others of said RF resonant circuits.

5. An RF tag as defined in claim 1 further including a body of solid material, said body having a length dimension, a width dimension, and a height dimension defining at least two, non-coplanar surfaces, and wherein said plurality of RF resonant circuits are disposed along said non-coplanar surfaces.

6. An RF tag as defined in claim 5 wherein said plurality of RF resonant circuits comprises plural sets of said RF resonant circuits and wherein each said set of RF resonant circuits is disposed along a respective given one of said non-planar surfaces.

7. An RF tag as defined in claim 5 wherein said body of solid material is cubic in configuration.

8. An RF tag as defined in claim 5 wherein said at least two, non-coplanar surfaces are also nonparallel surfaces.

9. An RF tag comprising a plurality of RF resonant circuits, each of said RF resonant circuits comprising a conductive portion which provides an inductance that determines an electrical resonant frequency for said resonant circuit, said RF resonant circuits being spaced apart and disposed in a three-dimensional array of said RF resonant circuits, wherein said plurality of RF resonant circuits comprise plural sets of said RF resonant circuits, wherein the RF resonant circuits are disposed to form columns of said plural sets of said RF resonant circuits and to form rows of said plural sets of said RF resonant circuits and wherein said plural sets are disposed in substantially parallel and spaced part relation.

10. An RF tag as defined in claim 9 wherein said plural sets of RF resonant circuits are further disposed so as to be substantially coextensive with each other.

11. An RF tag as defined in claim 10 wherein said plurality of RF resonant circuits comprises at least two sets of said RF resonant circuits.

12. An RF tag as defined in claim 11 said at least two sets of RF resonant circuits include an equal number of RF resonant circuits forming said columns of RF resonant circuits and an equal number of RF resonant circuits forming said rows of RF resonant circuits.

13. An RF tag as defined in claim 12 wherein each said at least two sets of RF resonant circuits include an equal number of columns and rows of RF resonant circuits.

14. An RF tag as defined in claim 13 further including at least one additional set of said RF resonant circuits disposed between said at least two sets of RF resonant circuits.

15. An RF tag as defined in claim 14 wherein the RF resonant circuits of said at least one additional set of RF resonant circuits are disposed for forming only outer columns of said RF resonant circuits and outer rows of said RF resonant circuits.

16. An RF tag as defined in claim 15 wherein said RF tag includes N number of said sets of resonant circuits and said additional sets of resonant circuits, combined wherein said at least two sets of RF resonant circuits each include N number of columns and rows RF resonant circuits, wherein said RF tag includes N-2 of said additional sets of RF resonant circuits, and wherein said RF tag includes a total number (C) of said RF resonant circuits equal to:

C =(N)^3- (N-2)³ ;

wherein N>

2.

17. An RF tag as defined in claim 12 further including at least one additional set of said RF resonant circuits disposed between said at least two sets of RF resonant circuits.

18. An RF tag as defined in claim 17 wherein the RF resonant circuits of said at least one additional set of said RF resonant circuits are disposed for forming only outer columns of said RF resonant circuits and outer rows of said RF resonant circuits.

19. An RF tag comprising a plurality of RF resonant circuits, each of said each RF resonant circuits having a center axis, said plurality of RF resonant circuits being disposed in spaced apart and substantially axially aligned relation, wherein at least one of said plurality of RF resonant circuits includes a cone shaped body having a substantially circular base, an apex and a curved surface tapering to said base from said apex and inductance and capacitance means formed on said curved surface for resonating at a given RF frequency.

20. An RF tag as defined in claim 19 further including an elongated body of solid material and wherein said RF resonant circuits are disposed within said elongated body.

21. An RF tag comprising a plurality of RF resonant circuits, each of said plurality of resonant circuits having a center axis, said plurality of RF resonant circuits being disposed in spaced apart and substantially axially aligned relation, wherein at least one of said RF resonant circuits includes a spherical shaped body including an equator, a pair of opposite poles, and an arcurately tapered surface extending from said equator to each of said poles, and first inductance and capacitance means formed on said arcurately tapered surface between said equator and one of said poles, said first inductance and capacitance means for resonating at a first RF frequency.

22. An RF tag as defined in claim 21 wherein said at least one of said RF resonant circuits includes second inductance and capacitance means formed on said arcuately tapered surface between said equator and the other one of said poles, said second inductance and capacitance means for resonating at a second RF frequency.

23. An RF tag comprising a plurality of at least three RF resonant circuits, each of said plurality of RF resonant circuits having a center axis, said plurality of RF resonant circuits being disposed in spaced apart and substantially axially aligned relation, wherein each of said plurality Of RF resonant circuits includes inductance and capacitance means for resonating at a given RF frequency, said inductance means being substantially planar in configuration and said center axis for each of said resonant circuits being normal to the planar configuration of the inductance means.

24. An RF tag comprising:

an elongated body of solid materials having an axis; and

a plurality of RF resonant circuits disposed within said elongated body in spaced apart relation along said axis, said elongated body being columnar in configuration about its axis and said plurality of resonant circuits forming a columnar array, wherein at least one of said RF resonant circuits includes a cone shaped body having a substantially circular base, an apex, and a curved surface tapering to said base from said apex and inductance and capacitance means formed on said curved surface for resonating at a given RF frequency.

25. An RF comprising:

an elongated body of solid materials having an axis; and

a plurality of RF resonant circuits disposed within said elongated body in spaced apart relation along said axis, said elongated body being columnar in configuration about its axis and said plurality of resonant circuits forming a columnar array, wherein at least one of said RF resonant circuits includes a spherically shaped body including an equator, a pair of opposite poles, and an arcuately tapered surface extending from said equator to said poles, and first inductance and capacitance means formed on said arcuately tapered surface between said equator and one of said poles, said first inductance and capacitance means for resonating at a first RF frequency.

26. An RF tag as defined in claim 25 wherein said at least one RF resonant circuit further includes second inductance and capacitance means formed on said arcuately tapered surface between said equator and the other one of said poles, said second inductance and capacitance means for resonating at a second RF frequency.

27. An RF tag comprising:

an elongated body of solid materials having an axis; and

a plurality of RF resonant circuits disposed within said elongated body in spaced apart relation along said axis, said elongated body being columnar in configuration about its axis and said plurality of resonant circuits forming a columnar array, wherein at least three of said RF resonant circuits include inductance and capacitance means for resonating at a given RF frequency, and said inductance means being substantially planar in configuration, each of said planar inductance means being positioned in different planes.

28. An RF tag system comprising:

an RF tag including an elongated body, having an axis, of solid material and a plurality of RF resonant circuits disposed within said elongated body in spaced apart relation along said axis, each of said RF resonant circuits being resonant at a given predetermined frequency, said elongated body being columnar in configuration about its axis and said plurality of resonant circuits forming a columnar array, wherein at least three of said RF resonant circuits include inductance and capacitance means for resonating at a given RF frequency, and said inductance means being substantially planar in configuration, each of said planar inductance moans being positioned in different planes; and

an RF tag reader including a plurality of sensors for sensing the presence of said RF resonant circuits and an elongated slot for receiving said elongated body, said plurality of sensors being disposed adjacent to said elongated slot in spaced apart relation for alignment of each sensor with one of said RF resonant circuits when said elongated body is received by said elongated slot.

29. An RF tag system comprising:

an RF tag including an elongated body, having an axis, of solid material and a plurality of RF resonant circuits disposed within said elongated body in spaced apart relation along said axis, each of said RF resonant circuits being resonant at a given predetermined frequency; and

an RF tag reader including a plurality of sensors for sensing the presence of said RF resonant circuits and an elongated slot for receiving said elongated body, said plurality of sensors being disposed adjacent to said elongated slot in spaced apart relation for alignment of each sensor with one of said RF resonant circuits when said elongated body is received by said elongated slot,

wherein at least one of said RF resonant circuits includes a cone shaped body having a substantially circular base, an apex, and a curved surface tapering to said base from said apex and inductance and capacitance means formed on said curved surface for resonating at a given RF frequency.

30. An RF tag system comprising:

an RF tag including an elongated body, having an axis, of solid material and a plurality of RF resonant circuits disposed within said elongated body in spaced apart relation along said axis, each of said RF resonant circuits being resonant at a given predetermined frequency; and

an RF tag reader including a plurality of sensors for sensing the presence of said RF resonant circuits and an elongated slot for receiving said elongated body, said plurality of sensors being disposed adjacent to said elongated slot in spaced apart relation for alignment of each sensor with one of said RF resonant circuits when said elongated body is received by said elongated slot,

wherein at least one of said RF resonant circuits includes a spherically shaped body including an equator, a pair of opposite poles, and an arcuately tapered surface extending from said equator to each of said poles, and first inductance and capacitance means formed on said arcuately tapered surface between said equator and one of said poles, said first inductance and capacitance means for resonating at a first RF frequency.

31. An RF tag system as defined in claim 30 wherein said at least one RF resonant circuit further includes second inductance and capacitance means formed on said arcuately tapered surface between said equator and the other one of said poles, said second inductance and capacitance means for resonating at a second RF frequency.

32. A resonant circuit for use in an RF tag, said resonant circuit including a body of solid material having a nonplanar surface and inductance and capacitance means formed on said nonplanar surface for resonating at a given frequency, wherein said body is a spherical shaped body including an equator, a pair of poles, and an arcurately tapered surface extending from said equator to said poles to form said non-planar surface, and wherein said inductance and capacitance means are formed on said arcurately tapered surface between said equator and one of said poles.

33. An RF tag assembly comprising:

active RF circuit means for transmitting an identifying RF code signal for identifying said RF tag assembly;

passive RF circuit means including a plurality of RF resonant circuits, each said RF resonant circuit being responsive to received RF energy for resonating at a predetermined resonant frequency, the plurality of RF resonant circuits, by their resonant frequencies, together defining a detectable identification code for also identifying said RF tag assembly; and

enclosure means for encapsulating said active RF circuit means and said passive RF circuit means together.

34. An RF tag assembly as defined in claim 33 wherein said active RF circuit means is substantially planar in configuration and having at least one major planar surface, wherein said assembly further includes a layer of insulating material between said major planar surface and said passive RF circuit means.

35. An RF tag assembly as defined in claim 33 further including means for receiving an interrogation signal and wherein said active RF circuit means are responsive to the receipt of said interrogation signal for transmitting said identifying signal.