DETERMINISTIC EMI GRID LAYOUT FOR CONTROLLING OPTICAL DIFFRACTION

• US 20140158417A1
• Filed: 12/06/2012
• Published: 06/12/2014
• Est. Priority Date: 12/06/2012
• Status: Active Grant

• Current Assignee: Danbury Mission Technologies, LLC (AMERGINT Technologies, Inc.)
• Original Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Zmek, William Paul, Prince, Steven Sumner
• Granted Patent: US 9,861,019 B2
• Time in Patent Office: Days
• US Class Current: 174/389
• CPC Class Codes: H05K 9/0094 being light-transmitting, e.g. transparent, translucent

Abstract

An electromagnetic interference shield is disclosed. The electromagnetic interference shield includes an optically transparent substrate and a metallic coating on the optically transparent substrate. The metal coating is characterized by a plurality of apertures aligned in a pattern that is defined by a deterministic relation. Distances between each of the plurality of apertures and an observation point in an associated image plane are uncorrelated.

Claims

1. An electromagnetic interference shield, comprising:

an optically transparent substrate;

a metallic coating on the optically transparent substrate, the metal coating characterized by a plurality of apertures aligned in a pattern that is defined by a deterministic relation, wherein distances between each of the plurality of apertures and an observation point in an associated image plane are uncorrelated.

2. The electromagnetic interference shield of claim 1, wherein a parameter of the pattern is selected to control at least one of:

(i) an electrical property of the metallic coating; and

(ii) an optical property of the metallic coating.

3. The electromagnetic interference shield of claim 1 wherein the alignment of the plurality of apertures in the pattern provides a substantially uniform average distribution of metal in the metallic coating.

4. The electromagnetic interference shield of claim 1 wherein the pattern of the plurality of apertures in the metallic coating produces an uncorrelated phase relation of light, diffracted upon passing through the metal coating, at an image plane of the metallic coating.

5. The electromagnetic interference shield of claim 4, wherein the uncorrelated phase relation reduces an appearance of side lobes at the image plane.

6. The electromagnetic interference shield of claim 1 wherein the deterministic relation further comprises an Archimedes spiral.

7. The electromagnetic interference shield of claim 6, wherein a parameter of the pattern includes a parameter of the spiral, a thickness of the plurality of apertures, a shape of the plurality of apertures.

8. The electromagnetic interference shield of claim 1, wherein adjacent apertures are at least one of non-overlapping and contacting each other at their boundaries.

9. A method of shielding an object from an electromagnetic signal, comprising:

forming a metallic coating characterized by a plurality of apertures aligned in a pattern that is defined by a deterministic relation, wherein distances between each of the plurality of apertures and an observation point in an associated image plane are uncorrelated; and

placing the metallic coating between the object and the electromagnetic signal.

10. The method of claim 9 further comprising selecting a parameter of the metallic coating to control at least one of:

(i) an electrical property of the metallic coating; and

(ii) an optical property of the metallic coating.

11. The method of claim 9, wherein the alignment of the plurality of apertures in the pattern provides a substantially uniform average distribution of metal in the metallic coating.

12. The method of claim 9 wherein the pattern of the plurality of apertures in the metallic coating produces an uncorrelated phase relation of the light that is diffracted upon passing through the metal coating at an image plane of the metallic coating.

13. The method of claim 12, wherein the uncorrelated phase relation reduces generation of side lobes by light passing through the metallic mesh.

14. The method of claim 9 wherein the deterministic relation further comprises an Archimedes spiral.

15. The method of claim 14, wherein a parameter of the pattern includes a parameter of the spiral, a thickness of the plurality of apertures, a shape of the plurality of apertures.

16. The method of claim 9, wherein adjacent apertures in the grid are at least one of non-overlapping and contacting each other at their boundaries.

17. A method of reducing diffraction effects in an electromagnetic interference shield, comprising:

forming the electromagnetic interference shield using a metallic coating having a plurality of apertures aligned in a pattern that is defined by a deterministic relation, wherein distances between each of the plurality of apertures and an observation point in an associated image plane are uncorrelated.

18. The method of claim 17, wherein the deterministic relation is and Archimedes spiral.

19. The method of claim 17, wherein the pattern of the plurality of apertures in the metallic coating produces an uncorrelated phase relation of light passing through the metal coating at an image plane of the metallic coating

20. The method of claim 19, wherein the uncorrelated phase relation reduces generation of side lobes at the image plane.