Lightning protection sheet with patterned discriminator

• US 9,516,727 B2
• Filed: 06/12/2014
• Issued: 12/06/2016
• 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:
  US14/302,660
• Publication Number:
  US 20140293498A1
• Time in Patent Office: 908 Days
• Field of Search: 361/218
• US Class Current: 1/1
• 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, and where the electrically conductive film is patterned with ridge-and-trench features intersecting with the valley features or ridge-and-trench features of the first discriminator layer.

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 T_DL.

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

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

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

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

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

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

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

11. The lightning protection sheet according to claim 2 wherein t is between 0.001 and 100 microns.

12. The lightning protection sheet according to claim 2 wherein t is between 0.01 and 10 microns.

13. The lightning protection sheet according to claim 2 wherein d is between 6 microns and 1 mm.

14. The lightning protection sheet according to claim 2 which contains an amount of electrically conductive material weighing less than 50 g/m².

15. The lightning protection sheet according to claim 2 additionally comprising a layer of ionizing paint.

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

17. The lightning protection sheet according to claim 3 wherein t is between 0.001 and 100 microns.

18. The lightning protection sheet according to claim 3 wherein t is between 0.01 and 10 microns.

19. The lightning protection sheet according to claim 3 wherein d is between 6 microns and 1 mm.

20. The lightning protection sheet according to claim 3 which contains an amount of electrically conductive material weighing less than 50 g/m².

21. The lightning protection sheet according to claim 3 additionally comprising a layer of ionizing paint.

22. A composite aircraft structure bearing the lightning protection sheet according to claim 3.

23. A lightning protection sheet comprising:

an electrically conductive film having thickness t;

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; and

an electrically non-conductive second discriminator layer adjacent the first discriminator layer, where the second discriminator layer is patterned with ridge-and-trench features intersecting with the valley features or ridge-and-trench features of the first discriminator layer.

24. The lightning protection sheet according to claim 23 wherein t is between 0.01 and 10 microns and the lightning protection sheet contains an amount of electrically conductive material weighing less than 50 g/m².