Lightning protection sheet with patterned discriminator

• US 8,760,838 B2
• Filed: 05/06/2013
• Issued: 06/24/2014
• 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:
  US13/887,521
• Publication Number:
  US 20130242453A1
• Time in Patent Office: 414 Days
• Field of Search: 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, where the first discriminator layer is patterned into a plurality of valley features having a 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, 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.

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

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

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

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

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

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

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