Composite EMI shield having clean, highly conductive surfaces for conductive bonding

• US 5,250,342 A
• Filed: 04/16/1992
• Issued: 10/05/1993
• Est. Priority Date: 05/24/1989
• Status: Expired due to Fees

• Current Assignee: United Technologies Corporation (Rtx Corporation)
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: Lang, Charles F., DiGenova, Rocco R.
• Primary Examiner(s): Robinson, Ellis P.
• Assistant Examiner(s): Watkins, III, William P.
• Application Number:
  US07/869,873
• Time in Patent Office: 537 Days
• Field of Search: 361/218, 174/35 R, 174/35 MS, 428/138, 428/166, 428/458, 428/134, 428/139, 428/140, 428/246, 428/247, 428/256, 428/408, 428/290, 428/251, 428/252, 428/268, 428/433, 428/475.2, 428/344, 428/41, 428/42
• US Class Current: 428/138
• CPC Class Codes: H05K 9/009 comprising electro-conductive fibres, e.g. metal fibres, carbon fibres, metallised textile fibres, electro-conductive mesh, woven, non-woven mat, fleece, cross-linked
• CPC Class Codes: Y10T 428/1438 Metal containing
• CPC Class Codes: Y10T 428/24298 Noncircular aperture [e.g., slit, diamond, rectangular, etc.]
• CPC Class Codes: Y10T 428/24331 including nonapertured component
• CPC Class Codes: Y10T 428/24339 Keyed
• CPC Class Codes: Y10T 428/24347 From both sides
• CPC Class Codes: Y10T 428/24562 Interlaminar spaces
• CPC Class Codes: Y10T 428/2804 Next to metal
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer
• CPC Class Codes: Y10T 428/31681 Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31736 Next to polyester

Abstract

An EMI shield is disclosed for providing EMI protection. The shield is lightweight, and easily moldable into complex shapes, having conductive mating surfaces provided on opposite sides thereof. The clean, highly conductive mating surfaces are part of an embedded aluminum wire mesh sandwiched between at least two face plies which add strength to the shield. By sandwiching the metal mesh alternately with a nonporous tape, and a barrier tape ply, clean conductive areas can be provided on either side of the shield, easing attachment to adjacent structures. During curing, the tapes prevent direct resin inclusion into the metal mesh. After curing, the nonporous tape is removed to expose the clean, highly conductive mating surfaces.

Claims

1. A composite EMI shield comprising:

at least one conductive layer for lightning or electromagnetic interference shielding;

face plies on opposite sides of the conductive layer, each face ply having cutout areas to accommodate mating surfaces;

barrier tape, placed behind the conductive layer, between the conductive layer and the corresponding face ply, complimentary to the cutout areas; and

,

removable nonporous tape placed in the cutout areas adjacent the face plies.

2. The shield of claim 1 wherein said conductive layer comprises a conductive metal mesh or metal foil ply.

3. The shield of claim 1 wherein said conductive layer comprises aluminum metal mesh.

4. The shield of claim 1 wherein said face plies comprise fiberglass, graphite or polyaramid fiber reinforced, resin impregnated composite plies.

5. The shield of claim 1 wherein said nonporous tape comprises a copper foil with a polyester film facing and adhesive backing.

6. The shield of claim 1 wherein the barrier tape comprises a low flow film adhesive.

7. The shield of claim 1 wherein the barrier tape comprises a polyester film tape.

8. The shield of claim 1 further comprising one or more reinforcing plies placed between the barrier tape and the face ply to strengthen the mating surfaces.

9. The shield of claim 8 wherein said reinforcing plies comprise fiberglass, graphite or polyaramid fiber reinforced, resin impregnated composite plies.

17. The shield of claim 1 wherein the barrier tape comprises a polyester film tape with an adhesive peel ply backing.

10. A composite EMI shield comprising:

two conductive sheets placed together to form a conductive layer for lightning or electromagnetic interference shielding;

face plies on opposite sides of the conductive layer, each face ply having cutout areas to accommodate mating surfaces;

removable nonporous tape placed in the cutout areas adjacent the face plies;

barrier tape, placed behind the conductive layer, between the conductive layer and the corresponding face ply, complimentary to the cutout areas; and

,

one or more reinforcing plies placed between the barrier tape and the face ply to strengthen the mating surfaces.

11. The shield of claim 10 wherein said conductive layer comprises a pair of conductive metal mesh or metal foil plies.

12. The shield of claim 10 wherein said conductive layer comprises aluminum metal mesh plies.

13. The shield of claim 10 wherein said face plies and reinforcing plies comprise fiberglass, graphite or polyaramid fiber reinforced, resin impregnated composite plies.

14. The shield of claim 10 wherein said nonporous tape comprises a copper foil with a polyester film facing and adhesive backing.

15. The shield of claim 10 wherein the barrier tape comprises a low flow film adhesive.

16. The shield of claim 10 wherein the barrier tape comprises a polyester film tape.

18. The shield of claim 10 wherein the barrier tape comprises a polyester film tape with an adhesive peel ply backing.