RFID tag for an object having metallic portions, tag coupler and method thereof

• US 7,245,219 B2
• Filed: 08/06/2003
• Issued: 07/17/2007
• Est. Priority Date: 11/15/2002
• Status: Active Grant

• Current Assignee: Identive Group Incorporated
• Original Assignee: FCI Smartag Pte Ltd. (Identiv, Inc.)
• Inventors: Low, Koo Song, Du, Mingzhe, Toh, Weng Sang-See, Tan, Geok Leong, Lian, Tiang Siong
• Primary Examiner(s): Hofsass; Jeffery
• Assistant Examiner(s): Labbees; Edny
• Application Number:
  US10/513,496
• Publication Number:
  US 20050151651A1
• Time in Patent Office: 1,441 Days
• Field of Search: 340/572.1, 340/572.2, 340/572.3, 340/572.4, 340/572.5, 340/572.6, 340/572.7, 340/572.8, 340/572.9
• US Class Current: 340/572.1
• CPC Class Codes: G06K 19/045 the record carrier being of the non-contact type, e.g. RFID, and being specially adapted for attachment to a disc, e.g. a CD or DVD
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• 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 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
• CPC Class Codes: G08B 13/2414 using inductive tags
• CPC Class Codes: G08B 13/2417 having a radio frequency identification chip
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

An RFID tag (20) has an electrically non-conductive substrate (22) with a mounting surface (24), an electrically conductive member (26), a conductive bridge (28), a dielectric strip (30), and a semiconductor device (32). The member (26) is mounted to the surface (24) and has an inner section (38), an outer section (40) and a connecting section (42). The section (38) has windings (44) and a free end (46) extending from one of the windings. The section (40) substantially surrounds the section (38) and has a winding (50) and a free end (52) that extends from a portion (54) of the winding (50) towards the section (38). A segment (56) of the section (42) is disposed between the ends (46, 52). The bridge (28) spans from the end (46) to the end (52). With the strip (30) disposed between the bridge (28) and the member (26), capacitive sections are thereby formed along the strip (30).

Claims

1. A radio frequency identification (RFID) tag comprising:

a substantially planar and electrically non-conductive substrate having a mounting surface;

a substantially planar and electrically conductive member mounted to said mounting surface, said conductive member having;

an inner section comprising;

one or more windings;

a broken section between a first and a second open positions in one of said windings; and

an inner section free end extending from said first open position;

an outer section, being disposed near the edge of said mounting surface and substantially surrounding said inner section, said outer section comprising;

one or more windings with the innermost winding being significantly separated from the outermost winding of said inner section with respect to the average pitch value of said inner section windings;

the width of said outer section windings may be different from the width of said inner section windings; and

an outer section free end extending from the outermost winding of said outer section;

a connecting section connecting said second open position of said inner section to the innermost winding of said outer section;

a conductive bridge crossing over a connecting segment within said connecting section and spanning from said inner section free end to said outer section free end; and

at least one dielectric strip disposed between said conductive bridge and said conductive member to thereby form one or more capacitive sections along said at least one dielectric strip.

2. The RFID tag of claim 1, wherein said connecting segment is disposed between said inner section free end and said outer section free end.

3. The RFID tag of claim 2, wherein said capacitive sections comprise a capacitive section at a portion of said connecting segment.

4. The RFID tag of claim 3, wherein said capacitive sections further comprise another capacitive section at a portion of said inner section free end.

5. The RFID tag of claim 3, wherein said capacitive sections further comprise another capacitive section at a portion of said outer section free end.

6. The RFID tag of claim 1, and further comprising a semiconductor device having at least two terminals electrically and respectively connected to at least two conductive pads of said conductive member.

7. The RFID tag of claim 6, wherein said at least two conductive pads are disposed in association with said windings of said inner section.

8. The RFID tag of claim 1, wherein said inner section free end extends towards said outer section.

9. The RFID tag of claim 1, wherein said outer section free end extends towards said inner section.

10. The RFID tag of claim 1, wherein said connecting section extends from the outermost winding of said inner section to the innermost winding of said outer section.

11. The RFID tag of claim 1, wherein said non-conductive substrate has a spindle aperture formed at a center portion thereof.

12. The RFID tag of claim 1, wherein said inner section comprises an indented section, said indented section having two free ends, each of said two free ends extending from a winding of said inner section.

13. The RFID tag, of claim 12, wherein said indented section comprises a conductive bridge connecting said two free ends.

14. The RFID tag of claim 13, wherein at least one dielectric strip is disposed between said conductive bridge and said two free ends to thereby form one or more capacitive sections along said at least one dielectric strip.

15. The RFID tag of claim 13, wherein said winding of each of said two free ends are separated by other windings of said inner section at said indented section.

16. A tag coupler for a radio frequency identification (REID) tag housed within a product carrier, said tag coupler comprising:

an electrically conductive member having;

an inner section comprising;

one or more windings;

a broken section between a first and a second open positions in one of said windings; and

an inner section free end extending from said first open position;

an outer section, being disposed near the edge of said mounting surface and substantially surrounding said inner section, said outer section comprising;

one or more windings with the innermost winding being significantly separated from the outermost winding of said inner section with respect to the average pitch value of said inner section windings; and

an outer section free end extending from the outermost winding of said outer section;

a connecting section connecting said second open position of said inner section to the innermost winding of said outer section;

a conductive bridge crossing over a connecting segment within said connecting section and spanning from said inner section free end to said outer section free end; and

at least one dielectric strip disposed between said conductive bridge and said conductive member to thereby form one or more capacitive sections along said at least one dielectric strip.

17. The tag coupler of claim 16, wherein said connecting segment is disposed between said inner section free end and said outer section free end.

18. The tag coupler of claim 17, wherein said capacitive sections comprise a capacitive section at a portion of said connecting segment.

19. The tag coupler of claim 18, wherein said capacitive sections further comprise another capacitive section at a portion of said inner section free end.

20. The tag coupler of claim 18, wherein said capacitive sections further comprise another capacitive section at a portion of said outer section free end.

21. The tag coupler of claim 16, wherein said inner section free end extends towards said outer section.

22. The tag coupler of claim 16, wherein said outer section free end extends towards said inner section.

23. The tag coupler of claim 16, wherein said connecting section extends from the outermost winding of said inner section to the innermost winding of said outer section.

24. The tag coupler of claim 16, and further comprising a substantially planar substrate having an electrically non-conductive mounting surface, said mounting surface being for mounting said conductive member.

25. A method of forming a radio frequency identification (RFID) tag, said method comprising:

providing a substantially planar and electrically non-conductive substrate having a mounting surface;

forming a substantially planar and electrically conductive member on said mounting surface, said conductive member having;

an inner section comprising;

one or more windings;

a broken section between a first and a second open positions in one of said windings; and

an inner section free end extending from said first open position;

an outer section, being disposed near the edge of said mounting surface and substantially surrounding said inner section, said outer section comprising;

one or more windings with its innermost winding being significantly separated from the outermost winding of said inner section with respect to the average pitch value of said inner section windings;

the width of said outer section windings may be different from the width of said inner section windings; and

an outer section free end extending from the outermost winding of said outer section;

said second open position of said inner section and the inner most winding of said outer section being connected via a connecting section, said connecting section being disposed between said inner section free end and said outer section free end;

attaching at least one dielectric strip onto one or more portions of said conducive member; and

printing a conductive bridge which crosses over said connecting segment and spans from said inner section free end to said outer section free end onto said at least one dielectric strip;

wherein said at least one dielectric strip disposed between said conductive bridge and said conductive member to thereby form one or more capacitive sections along said at least one dielectric strip.

26. The method of claim 25, wherein said forming comprises:

laminating a conductive material onto said mounting surface; and

etching said conductive material to thereby form said conductive member.

27. The method of claim 25, wherein said attaching comprises printing said at least one dielectric strip onto a portion of said connecting segment.

28. The method of claim 27, wherein said attaching further comprises printing said at least one dielectric strip onto a portion of said inner section free end.

29. The method of claim 27, wherein said attaching further comprises printing said at least one dielectric strip onto a portion of said outer section free end.

30. The method of claim 27, wherein said attaching further comprises curing said at least one dielectric strip.

31. The method of claim 25, and further comprising mounting a semiconductor device to at least two conductive pads of said conductive member.

32. The method of claim 25, and further comprising applying an adhesive onto an attachment surface of said non-conductive substrate, said attachment surface being opposite to said mounting surface.

33. The method of claim 25, and further comprising shaping said non-conductive substrate for attachment to a component.

34. The method of claim 33, wherein said shaping comprises punching a spindle aperture at a center portion of said non-conductive substrate.

35. The method of claim 25, wherein said forming comprises forming an indented section at said inner section, said indented section having two free ends, each of said two free ends extending from a winding of said inner section.

36. The method of claim 35, wherein said attaching comprises printing at least one dielectric strip onto one or more portions of said indented section.

37. The method of claim 36, wherein said attaching further comprises curing said at least one dielectric strip.

38. The method of claim 36, wherein said printing comprises printing a conductive bridge onto at least one portion of said at least one dielectric strip to thereby form one or more capacitive sections along said at least one dielectric strip at said indented section.