Low cost electromagnetic field absorbing devices manufactured from conductive loaded resin-based materials

• US 20040239578A1
• Filed: 06/08/2004
• Published: 12/02/2004
• Est. Priority Date: 02/15/2001
• Status: Active Grant

• Current Assignee: Integral Technologies, Inc.
• Original Assignee: Integral Technologies, Inc.
• Inventors: Aisenbrey, Thomas
• Granted Patent: US 7,079,086 B2
• Time in Patent Office: Days
• US Class Current: 343/872
• CPC Class Codes: B29C 45/0001 characterised by the choice of material
• CPC Class Codes: B29C 45/0013 using fillers dispersed in the moulding material, e.g. metal particles
• CPC Class Codes: B29C 70/58 comprising fillers only , e.g. particles, powder, beads, flakes, spheres B29C70/025 takes precedence, agglomerating hollow spheres to produce synthetic foam B29C70/66; compounding ingredients per se C08K
• CPC Class Codes: B29C 70/882 partly or totally electrically conductive, e.g. for EMI shielding conductive floors or floor coverings H05F3/025; EMI shielding in general H05K9/00
• CPC Class Codes: B29K 2995/0005 Conductive
• CPC Class Codes: B29L 2031/3456 Antennas, e.g. radomes
• 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: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 17/00 Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
• CPC Class Codes: H01R 13/6599 Dielectric material made conductive, e.g. plastic material coated with metal
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: H05K 2201/0281 Conductive fibers
• CPC Class Codes: H05K 2201/09118 Moulded substrate
• CPC Class Codes: H05K 2203/0113 Female die used for patterning or transferring, e.g. temporary substrate having recessed pattern
• CPC Class Codes: H05K 3/101 by casting or moulding of conductive material
• CPC Class Codes: H05K 3/107 by filling grooves in the support with conductive material H05K3/045, H05K3/101, H05K3/1258 and H05K3/465 take precedence
• CPC Class Codes: Y10T 428/1328 Shrinkable or shrunk [e.g., due to heat, solvent, volatile agent, restraint removal, etc.]
• CPC Class Codes: Y10T 428/249972 Resin or rubber element

Abstract

Electromagnetic absorbing devices are formed of a conductive loaded resin-based material. The conductive loaded resin-based material comprises micron conductive powder(s), conductive fiber(s), or a combination of conductive powder and conductive fibers in a base resin host. The ratio of the weight of the conductive powder(s), conductive fiber(s), or a combination of conductive powder and conductive fibers to the weight of the base resin host is between about 0.20 and 0.40. The micron conductive powders are formed from non-metals, such as carbon, graphite, that may also be metallic plated, or the like, or from metals such as stainless steel, nickel, copper, silver, that may also be metallic plated, or the like, or from a combination of non-metal, plated, or in combination with, metal powders. The micron conductor fibers preferably are of nickel plated carbon fiber, stainless steel fiber, copper fiber, silver fiber, or the like.

Claims

1. An electromagnetic absorbing device comprising a conductive loaded, resin-based material comprising conductive materials in a base resin host wherein the ratio, by weight, of said conductive materials to said resin host is between about 0.20 and about 0.40.

2. The device according to claim 1 wherein said conductive materials comprise metal powder.

3. The device according to claim 2 wherein said metal powder is nickel, copper, or silver.

4. The device according to claim 2 wherein said metal powder is a non-conductive material with a metal plating.

5. The device according to claim 4 wherein said metal plating is nickel, copper, silver, or alloys thereof.

6. The device according to claim 2 wherein said metal powder comprises a diameter of between about 3 μ

m and about 12 μ

m.

7. The device according to claim 1 wherein said conductive materials comprise non-metal powder.

8. The device according to claim 7 wherein said non-metal powder is carbon, graphite, or an amine-based material.

9. The device according to claim 1 wherein said conductive materials comprise a combination of metal powder and non-metal powder.

10. The device according to claim 1 wherein said conductive materials comprise micron conductive fiber.

11. The device according to claim 10 wherein said micron conductive fiber is nickel plated carbon fiber, stainless steel fiber, copper fiber, silver fiber or combinations thereof.

12. The device according to claim 10 wherein said micron conductive fiber has a diameter of between about 3 μ

m and about 12 μ

m and a length of between about 2 mm and about 14 mm.

13. The device according to claim 1 wherein said conductive materials comprise a combination of conductive powder and conductive fiber.

14. The device according to claim 1 wherein said electromagnetic absorbing device is part of a casing for an electronic device.

15. The device according to claim 14 wherein said electronic device is a mobile communications device.

16. The device according to claim 1 wherein said electromagnetic absorbing device surrounds an integrated circuit device.

17. The device according to claim 1 further comprising a solderable layer overlying at least a part of said conductive loaded, resin-based material.

18. The device according to claim 1 wherein said electromagnetic absorbing device comprises a chamber capable of holding an electronic device under test.

19. The device according to claim 1 wherein said electromagnetic absorbing device mimics a human body part.

20. The device according to claim 19 wherein said human body part comprises a hand.

21. The device according to claim 19 wherein said human body part comprises a head.

22. The device according to claim 19 further comprising a flexible tendon structure embedded in said conductive loaded, resin-based material.

23. The device according to claim 19 wherein said conductive loaded, resin-based material is flexible.

24. The device according to claim 1 further comprising a metal layer overlying at least a part of said conductive loaded, resin-based material.

25. A mobile communications device comprising:

an electronic circuit; and

an electromagnetic absorbing device comprising a conductive loaded, resin-based material comprising conductive materials in a base resin host wherein the ratio, by weight, of said conductive materials to said resin host is between about 0.20 and about 0.40 and wherein said electromagnetic absorbing device comprises a part of the casing for said mobile communications device.

26. The device according to claim 25 wherein said conductive materials comprise metal powder.

27. The device according to claim 26 wherein said metal powder is a non-conductive material with a metal plating.

28. The device according to claim 25 wherein said conductive materials comprise non-metal powder.

30. The device according to claim 25 wherein said conductive materials comprise a combination of metal powder and non-metal powder.

31. The device according to claim 25 wherein said conductive materials comprise micron conductive fiber.

32. The device according to claim 25 wherein said conductive materials comprise a combination of conductive powder and conductive fiber.

33. The device according to claim 25 further comprising a metal layer overlying at least a part of said conductive loaded, resin-based material.

34. An electromagnetic absorbing device comprising a conductive loaded, resin-based material comprising conductive materials in a base resin host wherein the ratio, by weight, of said conductive materials to said resin host is between about 0.20 and about 0.40 and wherein said electromagnetic absorbing device mimics a part of the human body.

35. The device according to claim 34 wherein said conductive materials comprise metal powder.

36. The device according to claim 35 wherein said metal powder is a non-conductive material with a metal plating.

37. The device according to claim 34 wherein said conductive materials comprise non-metal powder.

38. The device according to claim 34 wherein said conductive materials comprise a combination of metal powder and non-metal powder.

39. The device according to claim 34 wherein said conductive materials comprise micron conductive fiber.

40. The device according to claim 34 wherein said conductive materials comprise a combination of conductive powder and conductive fiber.

41. The device according to claim 34 further comprising a metal layer overlying at least a part of said conductive loaded, resin-based material.

42. The device according to claim 34 wherein said human body part comprises a hand.

43. The device according to claim 34 wherein said human body part comprises a head.

44. The device according to claim 34 further comprising a flexible tendon structure embedded in said conductive loaded, resin-based material.

45. The device according to claim 34 wherein said conductive loaded, resin-based material is flexible.

46. A method to form an electromagnetic absorbing device, said method comprising:

providing a conductive loaded, resin-based material comprising conductive materials in a resin-based host; and

molding said conductive loaded, resin-based material into an electromagnetic absorbing device.

47. The method according to claim 46 wherein the ratio, by weight, of said conductive materials to said resin host is between about 0.20 and about 0.40.

48. The method according to claim 46 wherein the conductive materials comprise a conductive powder.

49. The method according to claim 46 wherein said conductive materials comprise a micron conductive fiber.

50. The method according to claim 46 wherein said conductive materials comprise a combination of conductive powder and conductive fiber.

51. The method according to claim 46 wherein said molding comprises:

injecting said conductive loaded, resin-based material into a mold;

curing said conductive loaded, resin-based material; and

removing said electromagnetic absorbing device from said mold.

52. The method according to claim 46 wherein said molding comprises:

loading said conductive loaded, resin-based material into a chamber;

extruding said conductive loaded, resin-based material out of said chamber through a shaping outlet; and

curing said conductive loaded, resin-based material to form said electromagnetic absorbing device.

53. The method according to claim 52 further comprising stamping or milling said molded conductive loaded, resin-based material.