EMI shielding for components

• US 5,483,423 A
• Filed: 01/09/1995
• Issued: 01/09/1996
• Est. Priority Date: 11/16/1993
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Tusler, Ralph M., Martinez, Reuben M., Lewis, Mark S.
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): Whang, Young
• Application Number:
  US08/375,041
• Time in Patent Office: 365 Days
• Field of Search: 361/760, 361/761, 361/800, 361/814, 361/816, 361/818, 174/35 R, 174/35 GC, 174/35 TS, 439/109, 439/108, 439/607-609, 257/659
• US Class Current: 361/816
• CPC Class Codes: G06F 1/182 with special features, e.g. for use in industrial environments; grounding or shielding against radio frequency interference [RFI] or electromagnetical interference [EMI]
• CPC Class Codes: H05K 9/0062 Structures of standardised dimensions, e.g. 19" rack, chassis for servers or telecommunications

Abstract

This disclosure pertains to an apparatus and method of providing EMI shielding for an electrical component. The apparatus includes an elastomeric gasket, which is coated with a conductive jacket, and which is mounted on the backplane of a cabinet, the backplane providing EMI shielding. The cabinet is adapted for the insertion of a plurality of electrical components, such as disk drives, tape drives, and power supplies, which themselves are mounted in a rigid frame member. The frame member includes EMI shielding for the components on five of their six sides. The sixth side is unshielded, due to the fact that it contains the electrical connector used to connect the component to the backplane of the cabinet, when the frame member is inserted in the cabinet. With the frame member providing shielding on five sides, and the backplane providing shielding for the sixth side, the gasket serves the purpose of establishing an electrical seal between the frame member and the backplane of the cabinet.

Claims

1. Apparatus for shielding an electrical component comprising:

a container for holding the electrical component, the container being shielded against EMI emissions on all sides except one the unshielded side having an electrically conductive edge which defines a geometric shape;

a cabinet for holding the container, the cabinet including a wall constructed to shield EMI emissions; and

a gasket on the interior surface of the wall, the gasket having an elastomeric core and an electrically conductive outer surface, the gasket being in the given geometric shape such that with the electrically conductive edge of the unshielded side of the container in pressed contact with the outer surface of the gasket an electrical connection is established between the edge and the gasket.

2. The apparatus as in claim 1, wherein said core is an electrically insulative material.

3. The apparatus as in claim 2, wherein said insulative material is foam rubber.

4. The apparatus as in claim 2, wherein said gasket surface includes a conductive mesh.

5. The apparatus as in claim 1, wherein the container for holding the electrical component includes a plating of electrically conductive material which is electrically coupled to the electrically conductive edge.

6. The apparatus as in claim 5, wherein said conductive plating comprises a shield against EMI.

7. Apparatus for EMI shielding an electrical component comprising:

a cabinet including a backplane constructed to shield EMI emissions and having an opening on one side thereof;

a container for holding an electrical component, the container including a side having a component connector, the container being effective to shield an electrical component held therein from EMI emissions on all sides except the side with the component connector, the unshielded side of the container having an exteriorly exposed closed narrow electrically conductive surface extending around the outer boundary region of such side, the container having a shape and dimensions for insertion in the cabinet through the opening; and

a resilient electrically conductive surface on the interior of the backplane conforming in shape and size to the exteriorly exposed electrically conductive surface, the electrically conductive surface being positioned on the backplane so that when the container is in position in the cabinet such resilient electrically conductive surface engages the conductive surface on the unshielded side of the container to form electrical contact therewith.

8. The apparatus of claim 7 wherein the electrically conductive surface on the interior of the backplane is formed by a conductive outer cover of a gasket.

9. The apparatus as in claim 8, wherein the gasket includes an electrically insulated elastomeric core.

10. The apparatus as in claim 9, wherein said core is made of foam rubber.

11. The apparatus as in claim 9, wherein said gasket includes a conductive mesh over said core.

12. The apparatus of claim 7 wherein the interior surfaces of the container on all sides are formed of an electrically conductive metallic material except the side with the component connector.

13. The apparatus of claim 12 wherein the container is formed of plastic.

14. A method of shielding an electrical component comprising the steps of:

inserting a frame member which houses an electrical component into a cabinet, the frame member having a plurality of sides, one of which is unshielded against the emission of EMI, said unshielded side having an opening defined by an electrically conductive edge in a given geometric shape; and

compressively engaging a sealing gasket with the edge, the sealing gasket having an elastomeric core with a conductive surface and being mounted in the cabinet in the same geometric shape as the edge.

15. Apparatus for EMI shielding an electrical component comprising:

a cabinet including a backplane constructed to shield EMI emissions and having an opening on one side thereof;

a plastic container for holding an electrical component, the container including side, top, bottom, back walls, and a front cover, the interior of the side, top, and bottom walls and the front cover being coated with a metallic layer effective to shield against EMI emissions, the back wall having a component connector, the unshielded back wall of the container having an exteriorly exposed closed narrow electrically conductive surface extending around the outer boundary region of such back wall, the container having a shape and dimensions for insertion in the cabinet through the opening; and

a resilient electrically conductive surface on the interior of the backplane conforming in shape and size to the exteriorly exposed electrically conductive surface, the electrically conductive surface on the interior of the backplane is formed by a conductive outer cover of a gasket, the gasket includes an electrically insulated elastomeric core, the electrically conductive surface being positioned on the backplane so that when the container is in position in the cabinet such resilient electrically conductive surface engages the conductive surface on the unshielded back wall of the container to form electrical contact therewith.