LIGHTNING PROTECTION SHEET WITH PATTERNED DISCRIMINATOR

• US 20100264665A1
• Filed: 04/15/2010
• Published: 10/21/2010
• 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.
• Granted Patent: US 8,503,153 B2
• Time in Patent Office: Days
• US Class Current: 290/55
• 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, 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.

2. A lightning protection sheet according to claim 1 wherein the first discriminator layer is patterned into a plurality of valley features having a depth d of between 50% and 100% of T_DL.

3. A lightning protection sheet according to claim 1 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 50% T_DL.

4. The lightning protection sheet according to claim 3 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.

5. The lightning protection sheet according to claim 3 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.

6. The lightning protection sheet according to claim 1 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.

7. The lightning protection sheet according to claim 4 wherein the electrically non-conductive second discriminator layer comprises ionizable pigments.

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

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

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

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

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

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

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

15. 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.

16. The lightning protection sheet according to claim 15 wherein t is between 0.001 and 100 microns.

17. The lightning protection sheet according to claim 15 wherein t is between 0.01 and 10 microns.

18. The lightning protection sheet according to claim 15 wherein the average diameter of the particles is between 6 microns and 1 mm.

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

20. The lightning protection sheet according to claim 15 additionally comprising a layer of ionizing paint.

21. The lightning protection sheet according to claim 15 wherein the electrically non-conductive first discriminator layer comprises ionizable pigments.

22. A composite aircraft structure bearing the lightning protection sheet according to claim 15.

23. A wind turbine generator structure bearing the lightning protection sheet according to claim 15.