RFID device and method of forming
A radio frequency identification (RFID) inlay includes an electrical connection between a chip and an antenna. The electrical connection includes conductive interposer leads and a capacitive connection. The capacitive connection may involve putting the antenna and the interposer leads into close proximity, with dielectric pads therebetween, to allow capacitive coupling between the antenna and the interposer leads. The dielectric pads may include a non-conductive adhesive and a high dielectric material, such as a titanium oxide. The connections provide a convenient, fast, and effective way to operatively couple antennas and interposers. The RFID inlay may be part of an RFID lable or RFID tag.
1. A radio frequency identification (RFID) device comprising:
a substrate;
an antenna on the substrate; and
an interposer, wherein the interposer includes:
an RFID chip having contacts thereupon; and
interposer leads operatively coupled to the contacts of the chip;
wherein the interposer leads and the antenna are capacitively coupled together.
2. The RFID device of claim 1 , wherein the interposer leads and the antenna are capacitively coupled across a dielectric material is between the interposer leads and the antenna.
3. The RFID device of claim 2 , wherein the dielectric material is a dielectric layer.
4. The RFID device of claim 3 , wherein the dielectric layer is a printed dielectric layer.
5. The RFID device of claim 3 , wherein the dielectric layer is attached to the antenna.
6. The RFID device of claim 2 , wherein the dielectric material is an adhesive layer.
7. The RFID device of claim 6 , further comprising a non-adhesive material within the adhesive layer.
8. The RFID device of claim 7 , wherein the non-adhesive material is a dielectric non-adhesive material.
9. The RFID device of claim 8 , wherein the dielectric non-adhesive material includes a titanium compound.
10. The RFID device of claim 9 , wherein the titanium compound includes titanium dioxide.
11. The RFID device of claim 9 , wherein the titanium compound includes barium titanate.
12. The RFID device of claim 8 , wherein the dielectric non-adhesive material is at least 5% by volume of the non-conductive adhesive.
13. The RFID device of claim 7 , wherein the non-adhesive material includes electrically conductive particles therein.
14. The RFID device of claim 13 , wherein the conductive particles include aluminum particles.
15. The RFID device of claim 2 , wherein the dielectric material includes an interposer substrate that is part of the interposer, and is attached to the interposer leads.
16. The RFID device of claim 2 , wherein the dielectric material includes the substrate which the antenna is on.
17. The device of claim 16 , further comprising a second interposer that is also capacitively coupled to the antenna.
18. The device of claim 17 , wherein the interposers are on opposite sides (major surfaces) of the substrate.
19. The RFID device of claim 2 , wherein the interposer is attached to a label facestock layer.
20. The RFID device of claim 2 , wherein the dielectric material includes dielectric pads between the interposer leads and the antenna.
21. The RFID device of claim 20 , wherein the dielectric pads include a non-conductive adhesive.
22. The RFID device of claim 21 , wherein the non-conductive adhesive is a pressure-sensitive adhesive.
23. The RFID device of claim 21 , wherein the non-conductive adhesive includes a thermoset non-conductive adhesive.
24. The RFID device of claim 23 , wherein the dielectric non-adhesive material is interspersed within the non-conductive adhesive.
25. The RFID device of claim 24 , wherein the dielectric non-adhesive material includes a titanium compound.
26. The RFID device of claim 25 , wherein the titanium compound includes titanium dioxide.
27. The RFID device of claim 25 , wherein the titanium compound includes barium titanate.
28. The RFID device of claim 24 , wherein the dielectric non-adhesive material is at least 5% by volume of the non-conductive adhesive.
29. The RFID device of claim 28 , wherein the dielectric non-adhesive material is at least 10% by volume of the non-conductive adhesive.
30. The RFID device of claim 21 , wherein the non-conductive adhesive includes a thermoplastic hot-melt adhesive.
31. The RFID device of claim 21 , wherein the dielectric pads also includes a dielectric non-adhesive material.
32. The RFID device of claim 31 , wherein the non-conductive adhesive is a pressure-sensitive adhesive.
33. The RFID device of claim 31 , wherein the non-conductive adhesive includes a thermoset non-conductive adhesive.
34. The RFID device of claim 31 , wherein the non-conductive adhesive includes a thermoplastic hot-melt adhesive.
35. The RFID device of claim 20 , wherein the wherein the dielectric pads include a non-conductive polymer.
36. The RFID device of claim 20 , wherein the dielectric pads have a thickness of about 0.025 mm (0.001 inches) or less.
37. The RFID device of claim 20 , wherein the dielectric pads have a thickness of about 0.013 mm (0.0005 inches) or less.
38. The RFID device of claim 20 , wherein the dielectric pads have a thickness of about 0.0025 mm (0.0001 inches) or less.
39. The RFID device of claim 20 , wherein the dielectric pads include spacers interspersed within another dielectric material.
40. The RFID device of claim 39 , wherein the another dielectric material includes a non-conductive polymer.
41. The RFID device of claim 39 , wherein the another dielectric material includes a pressure-sensitive adhesive.
42. The RFID device of claim 39 , wherein the non-conductive adhesive includes a thermoset non-conductive adhesive.
43. The RFID device of claim 39 , wherein the non-conductive adhesive includes a thermoplastic hot-melt adhesive.
44. The RFID device of claim 20 , wherein the dielectric pads have an effective dielectric constant that is a non-constant function of thickness of the dielectric pads.
45. The RFID device of claim 44 , wherein the dielectric pads include electrically conductive particles therein.
46. The RFID device of claim 45 , wherein the conductive particles include aluminum particles.
47. The RFID device of claim 20 , wherein the capacitive coupling has an effective capacitive coupling area that is a non-constant function of thickness of the dielectric pads.
48. The RFID device of claim 20 , wherein portions of the antenna that are capacitively coupled to the interposer leads have a larger area than the interposer leads.
49. The RFID device of claim 20 , wherein portions of the antenna that are capacitively coupled to the interposer leads have a concave shape.
50. The RFID device of claim 20 , wherein coupling areas of the interposers are each less than about 36 mm 2 (0.056 in 2 ).
51. The RFID device of claim 20 , wherein the capacitive coupling is a self-compensating capacitive coupling that varies capacitance with variations of thickness of the dielectric pads.
52. The RFID device of claim 20 , wherein the capacitive coupling is a self-compensating capacitive coupling that varies capacitance with variations of relative alignment the antenna and the dielectric pads.
53. The RFID device of claim 1 ,
wherein the device includes an additional layer; and
wherein the substrate and the additional layer are adhesively coupled together.
54. The RFID device of claim 53 , wherein the substrate and the additional layer enclose the antenna and the interposer.
55. The RFID device of claim 53 , wherein the additional layer is a printable layer.
56. A radio frequency identification (RFID) device comprising:
an antenna; and
an interposer, wherein the interposer includes:
an RFID chip having contacts thereupon; and
interposer leads operatively coupled to the contacts of the chip;
wherein the interposer leads and the antenna are capacitively coupled together.
57. The RFID device of claim 56 , wherein the antenna is printed to at least partially overlap the interposer leads.
58. The RFID device of claim 57 , wherein the interposer is attached to a substrate over which the antenna is printed.
59. The RFID device of claim 57 , further comprising dielectric pads on the interposer leads between the interposer leads and the antenna.