Tamper resistant RFID tags and associated methods

• US 7,855,649 B2
• Filed: 10/22/2008
• Issued: 12/21/2010
• Est. Priority Date: 11/21/2007
• Status: Active Grant

• Current Assignee: Trovan Ltd
• Original Assignee: Trovan Ltd
• Inventors: Masin, Joseph V.
• Primary Examiner(s): Lieu; Julie
• Application Number:
  US12/288,638
• Publication Number:
  US 20090128340A1
• Time in Patent Office: 790 Days
• Field of Search: None
• US Class Current: 340/572.8
• CPC Class Codes: G06K 19/07798 part of the antenna or the integrated circuit being adapted for rupturing or breaking, e.g. record carriers functioning as sealing devices for detecting not-authenticated opening of containers electronic seals G09F3/03
• CPC Class Codes: G09F 3/0376 using a special technique to detect tampering, e.g. by ultrasonic or optical means
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making

Abstract

Systems and methods are disclosed for a tamper resistant RFID (radio frequency identification) tags that overcome the problems existing with previous RFID tags. The tamper resistant RFID tags described herein are particularly useful for tracking of liquid propane gas (LPG) containers and/or other types of containers or objects. Removal of the RFID tag, after it is attached, will destroy and/or render inoperable the RFID transponder within the tag so that removal and re-use is not practical or possible. One key feature of this tamper resistant RFID tag is the use of adhesive materials with differing adhesion characteristics with respect to the container material (e.g., metal) and the housing for the RFID tag (e.g., plastic) so that the RFID tag will tend to be destroyed when removal is attempted.

Claims

1. An assembly having a tamper resistant RFID tag, comprising:

an object having a surface;

a housing having a bottom surface, the housing further comprising a cavity within the bottom surface and one or more structures protruding from an inner wall of the cavity;

an RFID transponder positioned within the cavity;

a potting element within the cavity, the potting element engaging the RFID transponder and the one or more structures, the potting element comprising a material that is weaker than the housing; and

an adhesive positioned between the bottom surface of the housing and the surface of the object to adhere the housing and the potting element to the surface of the object, the adhesive comprising a material that bonds more strongly to the surface of the object than to the housing, bonds more strongly to the surface of the object than to the potting element, and bonds more strongly to the potting element than the housing so that the potting element will tend to break rendering the RFID transponder inoperable if the housing is pried off the object.

2. The assembly of claim 1, wherein the surface of the object comprises a metal material and the housing comprises a plastic material.

3. The assembly of claim 2, wherein the object comprises a metal container.

4. The assembly of claim 3, wherein the metal container holds liquid propane gas.

5. The assembly of claim 4, wherein a strength of adhesion for the adhesive to the surface of the metal container and to the potting element is 100 pounds per square inch or more greater than a strength of adhesion for the adhesive to the to the plastic housing.

6. The assembly of claim 1, wherein the housing has rounded edges and a profile of less than 4.5 mm.

7. The assembly of claim 1, wherein the surface of the object comprises a metal material, the housing comprises an acrylonitrile butadiene styrene (ABS) plastic material, and the potting element comprises an electronic grade epoxy encapsulant.

8. The assembly of claim 1, wherein the potting element comprises a material that is injectable in liquid form and then hardens over time.

9. The assembly of claim 1, wherein the one or more structures comprise a plurality of wedge structures.

10. The assembly of claim 9, wherein the wedge structures touch the RFID transponder.

11. The assembly of claim 1, wherein the RFID transponder comprises an encapsulated RFID transponder.

12. The assembly of claim 1, wherein the RFID transponder comprises a non-encapsulated RFID transponder.

13. The assembly of claim 1, wherein the housing comprises a ceramic material.

14. A method for forming an assembly having a tamper resistant RFID tag, comprising:

providing an object having a surface;

providing a housing having a bottom surface, the housing further comprising a cavity within the bottom surface and one or more structures protruding from an inner wall of the cavity;

positioning an RFID transponder within the cavity;

injecting a potting element within the cavity to engage the RFID transponder and the one or more structures, the potting element comprising a material that is weaker than the housing when hardened;

allowing the potting element to harden;

selecting an adhesive comprising a material that bonds more strongly to the surface of the object than to the housing, bonds more strongly to the surface of the object than to the potting element, and bonds more strongly to the potting element than the housing; and

applying the adhesive between the bottom surface of the housing and the surface of the object to adhere the housing and the potting element to the surface of the object so that the potting element will tend to break rendering the RFID transponder inoperable if the housing is pried off the object.

15. The method of claim 14, wherein the surface of the object comprises a metal material and the housing comprises a plastic material.

16. The method of claim 15, wherein the object comprises a metal container holding liquid propane gas.

17. The method of claim 16, wherein the selecting step comprises selecting an adhesive having a strength of adhesion to the surface of the metal container and to the potting element that is 100 pounds per square inch or more greater than a strength of adhesion for the adhesive to the to the plastic housing.

18. The method of claim 14, wherein the housing has rounded edges and a profile of less than 4.5 mm.

19. The method of claim 14, wherein the surface of the object comprises a metal material, the housing comprises an acrylonitrile butadiene styrene (ABS) plastic material, and the potting element comprises an electronic grade epoxy encapsulant.

20. The method of claim 14, wherein the one or more structures comprise a plurality of wedge structures.

21. The method of claim 20, further comprising positioning the RFID transponder so that the RFID transponder touches the plurality of wedge structures.

22. The method of claim 14, further comprising providing an encapsulated RFID transponder for the positioning step.

23. The method of claim 14, further comprising providing a non-encapsulated RFID transponder for the positioning step.