Lightning protection sheet with patterned discriminator

• US 8,503,153 B2
• Filed: 04/15/2010
• Issued: 08/06/2013
• Est. Priority Date: 04/17/2009
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Hebert, Larry S.
• Primary Examiner(s): BAUER, SCOTT ALLEN
• Application Number:
  US12/761,212
• Publication Number:
  US 20100264665A1
• Time in Patent Office: 1,209 Days
• Field of Search: 362/212, 362216-218, 361/212, 361216-218
• US Class Current: 361/212
• CPC Class Codes: B64C 1/12 Construction or attachment of skin panels
• CPC Class Codes: B64D 45/02 Lightning protectors; Static dischargers in general H01T
• CPC Class Codes: H02G 13/00 Installations of lightning conductors; Fastening thereof to supporting structure
• CPC Class Codes: H02G 13/80 Discharge by conduction or dissipation, e.g. rods, arresters, spark gaps
• CPC Class Codes: H05F 3/00 Carrying-off electrostatic charges from shoes A43B7/36; from living beings A61N1/14; from tyres B60C19/08; from vehicles B60R16/06; from aircraft B64D45/02; from large containers B65D90/46

Abstract

A lightning protection system is provided, typically for use on an outer surface of an aircraft, which includes the use of a lightning protection sheet that includes an electrically conductive film and at least one patterned, electrically non-conductive discriminator layer.

Claims

1. A lightning protection sheet comprising an electrically conductive film having thickness t and an electrically non-conductive first discriminator layer having thickness T_DL over the electrically conductive film, wherein the first discriminator layer is patterned into a first plurality of ridge-and-trench features having a trench depth d of between 50% and 100% of T_DL, additionally comprising an electrically non-conductive second discriminator layer covering portions of the first discriminator layer, wherein the second discriminator layer comprises a second plurality of ridge-and-trench features which are non-parallel with the first plurality of ridge-and-trench features.

2. The lightning protection sheet according to claim 1 wherein the electrically non-conductive second discriminator layer comprises ionizable pigments.

3. The lightning protection sheet according to claim 1 wherein the electrically non-conductive first discriminator layer comprises ionizable pigments.

4. The lightning protection sheet according to claim 1 wherein t is between 0.001 and 100 microns.

5. The lightning protection sheet according to claim 1 wherein t is between 0.01 and 10 microns.

6. The lightning protection sheet according to claim 1 wherein d is between 6 microns and 1 mm.

7. The lightning protection sheet according to claim 1 which contains an amount of electrically conductive material weighing less than 50 g/m².

8. The lightning protection sheet according to claim 1 additionally comprising a layer of ionizing paint.

9. A composite aircraft structure bearing the lightning protection sheet according to claim 1.

10. A lightning protection sheet comprising an electrically conductive film having thickness t and an electrically non-conductive first discriminator layer having thickness T_DL over the electrically conductive film, wherein the first discriminator layer is patterned into a first plurality of ridge-and-trench features having a trench depth d of between 50% and 100% of T_DL, wherein the electrically conductive film comprises a third plurality of ridge-and-trench features which are non-parallel with the first plurality of ridge-and-trench features.

11. The lightning protection sheet according to claim 10 wherein the electrically non-conductive first discriminator layer comprises ionizable pigments.

12. The lightning protection sheet according to claim 10 wherein t is between 0.001 and 100 microns.

13. The lightning protection sheet according to claim 10 wherein t is between 0.01 and 10 microns.

14. The lightning protection sheet according to claim 10 wherein d is between 6 microns and 1 mm.

15. The lightning protection sheet according to claim 10 which contains an amount of electrically conductive material weighing less than 50 g/m².

16. The lightning protection sheet according to claim 10 additionally comprising a layer of ionizing paint.

17. A composite aircraft structure bearing the lightning protection sheet according to claim 10.

18. A lightning protection sheet comprising an electrically conductive film having thickness t and an electrically non-conductive first discriminator layer having thickness T_DL over the electrically conductive film, where the first discriminator layer is patterned into a plurality of features selected from the group consisting valley features having a depth d of between 50% and 100% of T_DL, ridge-and-trench features having a trench depth d of between 50% and 100% of T_DL, or combinations thereof, additionally comprising an electrically non-conductive second discriminator layer covering portions of the first discriminator layer, where the first discriminator layer has a first dielectric breakdown strength and the second discriminator layer has a second dielectric breakdown strength that is less than 90% of the first dielectric breakdown strength.

19. The lightning protection sheet according to claim 18 wherein the electrically non-conductive second discriminator layer comprises ionizable pigments.

20. The lightning protection sheet according to claim 18 wherein the electrically non-conductive first discriminator layer comprises ionizable pigments.

21. The lightning protection sheet according to claim 18 wherein t is between 0.001 and 100 microns.

22. The lightning protection sheet according to claim 18 wherein t is between 0.01 and 10 microns.

23. The lightning protection sheet according to claim 18 wherein d is between 6 microns and 1 mm.

24. The lightning protection sheet according to claim 18 which contains an amount of electrically conductive material weighing less than 50 g/m².

25. The lightning protection sheet according to claim 18 additionally comprising a layer of ionizing paint.

26. A composite aircraft structure bearing the lightning protection sheet according to claim 18.

27. A lightning protection sheet comprising an electrically conductive film having thickness t and an electrically non-conductive first discriminator layer having thickness T_DL over the electrically conductive film, where the first discriminator layer comprises a first material having a first dielectric breakdown strength and particles of a second material having a second dielectric breakdown strength that is less than 90% of the first dielectric breakdown strength, where the average diameter of the particles is between 50% and 100% of T_DL.

28. The lightning protection sheet according to claim 27 wherein t is between 0.001 and 100 microns.

29. The lightning protection sheet according to claim 27 wherein t is between 0.01 and 10 microns.

30. The lightning protection sheet according to claim 27 wherein the average diameter of the particles is between 6 microns and 1 mm.

31. The lightning protection sheet according to claim 27 which contains an amount of electrically conductive material weighing less than 50 g/m².

32. The lightning protection sheet according to claim 27 additionally comprising a layer of ionizing paint.

33. The lightning protection sheet according to claim 27 wherein the electrically non-conductive first discriminator layer comprises ionizable pigments.

34. A composite aircraft structure bearing the lightning protection sheet according to claim 27.

35. A wind turbine generator structure bearing the lightning protection sheet according to claim 27.