Metal screened electronic labelling system

• US 6,956,481 B1
• Filed: 07/20/1999
• Issued: 10/18/2005
• Est. Priority Date: 07/20/1998
• Status: Expired due to Term

• Current Assignee: Gemalto SA (Thales SA)
• Original Assignee: Germplus
• Inventors: Cole, Peter
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US09/744,145
• Time in Patent Office: 2,282 Days
• Field of Search: 340/572.1, 340/572.4, 340/572.5, 340/572.6, 340/572.7, 340/551, 340/10.34, 235/375, 235/376, 235/435, 235/492, 235/493
• US Class Current: 340/572.4
• CPC Class Codes: G06K 19/07771 the record carrier comprising means for minimising adverse effects on the data communication capability of the record carrier, e.g. minimising Eddy currents induced in a proximate metal or otherwise electromagnetically interfering object
• CPC Class Codes: G06K 19/083 Constructional details
• CPC Class Codes: G06K 7/10178 including auxiliary means for focusing, repeating or boosting the electromagnetic interrogation field comparable booster antennas integrated on the record carrier itself G06K19/07794

Abstract

A metal screened (13) electronic labelling system having at least one information bearing electronic coded label including a label coil (12) and an interrogator including a transmitter coil (9). The system relies on a magnetic field coupling link containing the transmitter coil (9) and the label coil (12) for obtaining information from the label. The coupling link is arranged such that it operates in the near field thereof and substantially none or at most a minority of the magnetic flux which excites the label coil (12) also links the transmitter coil (9).

Claims

1. An electronic label reading system including:

at least one information bearing electronic coded label including a label antenna;

an interrogator including an interrogator antenna;

a magnetic field coupling link containing a transmitter coil and a receiver coil for communication between the interrogator and the label;

wherein the coupling link is arranged such that it operates in the near field of said transmitter coil and wherein substantially none or at most a minority of the magnetic flux which excites said receiver coil also links said transmitter coil.

2. An electronic label reading system as claimed in claim 1 wherein said interrogator includes said transmitter coil and said label includes said receiver coil.

3. An electronic label reading system as claimed in claim 1 wherein said label includes said transmitter coil and said interrogator includes said receiver coil.

4. An electronic label reading system as claimed in claim 3 wherein said label is placed in a slot in the metal object.

5. An electronic label reading system as claimed in claim 4 wherein the length of said slot, in the direction perpendicular to the path of currents in the region of the slot, is significantly greater than the length of the label coil or its ferrite core in that direction.

6. An electronic label reading system as claimed in claim 4 wherein the whole of said label is inside the main outline of said metal object.

7. An electronic label reading system as claimed in claim 4 wherein the object being labelled is an airline cargo pallet, and said label is locked in position by employing slots already made in said pallet for the purpose of cargo lock down.

8. An electronic label reading system as claimed in claim 7 wherein barbs on said label lock it in place in a re-entrant slot in the pallet.

9. An electronic label reading system as claimed in claim 7 wherein an interrogator antenna is placed parallel to and between rollers of a conveyor system.

10. An electronic label reading system as claimed in claim 9 wherein the rollers have a non-conducting surface or non-conducting bearings.

11. An electronic label reading system as claimed in claim 3 wherein the label coil is resonant in its operating frequency band.

12. An electronic label reading system as claimed in claim 11 wherein the resonant frequency is adjusted for proximity of the label to the metal of the object carrying the label.

13. An electronic label reading system as claimed in claim 1 wherein said transmitter or receiver coil contains a magnetic core.

14. An electronic label reading system as in claim 1 wherein said label antenna operated in proximity to a metal object and the metal object provides substantial reduction of the amount of magnetic field that would reach the receiver coil from the transmitter coil in relation to the magnetic field which would reach said receiver coil if the metal object were not present.

15. An electronic label reading system as claimed in claim 14 coil wherein the label coil is excited by a magnetic field created by surface currents on metal of an object carrying said label.

16. An electronic label reading system as claimed in claim 14 wherein currents are induced on one side of the metal object by said magnetic field, and wherein a pathway on said metal object allows those currents to pass to the other side of said metal object, and wherein said label is placed close to the currents on said other side of said metal object so that said label interacts with the magnetic field which accompanies said currents on said other side of said metal object.

17. An electronic label reading system as claimed in claim 16 wherein said pathway is provided by holes in said metal object.

18. An electronic label reading system as claimed in claim 17 wherein currents change direction when they reach said other side of said metal object.

19. An electronic label reading system as claimed in claim 17 wherein edges of the holes in said metal are perpendicular to the direction of said induced current.

20. An electronic label reading system as claimed in claim 17 wherein said holes are extended in the direction of a magnetic field created by said magnetic field creating antenna.

21. An electronic label reading system as claimed in claim 17 wherein said holes are a natural part of said object.

22. An electronic label reading system as claimed in claim 17 wherein said holes are added to said object.

23. An electronic label reading system as claimed in claim 16 wherein said currents induced on one side of said metal object travel toward an edge of said metal object.

24. An electronic label reading system as claimed in claim 16 wherein conduction current on said metal object does not flow in closed paths.

25. An electronic label reading system as claimed in claim 24 wherein the path of currents which flow on said metal object is completed by a displacement current.

26. An electronic label reading system as claimed in claim 1 wherein said coupling link is used for signaling from the interrogator to the label.

27. An electronic label reading system as claimed in claim 26 wherein the label may be read while a sheet of metal is interposed between the interrogator and the label.

28. An electronic label reading system as claimed in claim 27 wherein said sheet of metal is of substantial extent.

29. An electronic label reading system as claimed in claim 27 coil wherein the transmitter and receiver coils have parallel axes.

30. An electronic label reading system as claimed in claim 1 wherein said coupling link is used for signaling from the label to the interrogator.

31. An electronic label reading system as claimed in claim 1 wherein the interrogator provides power to the label to generate a reply from the label.

32. An electronic label reading system as claimed in claim 1 wherein the label generates replies intermittently.

33. An electronic label reading system as claimed in claim 32 wherein power for the label comes from power supplied by the transmitter during the period of the label giving a reply.

34. An electronic label reading system as claimed in claim 1 wherein said interrogator transmitter-receiver antenna comprises two separate antennas, one for transmission (3) and another for receiving (6), and said label transmitter-receiver antenna comprises a single antenna (5).

35. A method of obtaining information from an electronic label in proximity to a metal object, said label containing a label antenna, said method including the steps of:

providing an interrogator containing an interrogator antenna;

providing a magnetic field coupling link containing a transmitter coil and a receiver coil for communication between the interrogator and the label; and

arranging said coupling link such that it operates in the near field of said transmitter coil and wherein substantially none or at most a minority of the magnetic flux which excites said receiver coil also links said transmitter coil.

36. A method as claimed in claim 35 wherein said interrogator includes said transmitter coil and said label includes said receiver coil.

37. A method as claimed in claim 35 wherein said label includes said transmitter coil and said interrogator includes said receiver coil.

38. An electronic label reading system comprising,

an electronic coded label (4) having an antenna coil (12) and at least one item of information, said label being in proximity to a metal object (13),

an interrogator (1) including a transmitter coil (3) and a receiver coil (6),

said metal object substantially screening said label from the interrogator (1), and

said metal object (13) further includes a pathway on it to allow surface currents induced by the interrogator on one side of said metal object to pass to the other side and to create a magnetic field (13C) exciting the label antenna coil (12).

39. A method of obtaining information from an electronic label in proximity to a metal object that substantially screens the label from an interrogator (1) containing a transmitter coil (3) and a receiver coil (6) comprising the steps of:

producing induced surface currents (13A) on one side of the metal object by a magnetic field of the interrogator,

defining a pathway on said metal object (13) to allow the surface currents induced by the interrogator on one side of said metal object to pass to the other side and to create a magnetic field (13C) exciting the label antenna coil (12).