Method and apparatus for EMI shielding

• US 6,992,894 B1
• Filed: 03/17/2003
• Issued: 01/31/2006
• Est. Priority Date: 03/17/2003
• Status: Expired due to Fees

• Current Assignee: Unisys Corporation
• Original Assignee: Unisys Corporation
• Inventors: Mease, Keith D., Louth, Terry W., Jochym, Daniel A., Smith, Grant M., Wessel, Mark W., Gibbs, Ronald T.
• Primary Examiner(s): Vortman, Anatoly
• Application Number:
  US10/390,419
• Time in Patent Office: 1,051 Days
• Field of Search: 361709-723, 361/697, 361/704, 361/707, 361/753, 361/799, 361/696, 361/800, 257705-707, 257/713, 257717-719, 248/510, 244/58
• US Class Current: 361/719
• CPC Class Codes: G06F 1/20 Cooling means
• CPC Class Codes: H01L 23/4093 Snap-on arrangements, e.g. clips
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 9/0016 having a spring contact

Abstract

An apparatus and method are provided for dissipating heat from an electronic component mounted in a conductive enclosure and for shielding electromagnetic radiation generated by the electronic component. A heat sink is configured to be mounted in thermal contact with the electronic component. An electrical conductor is operatively connected to the heat sink and configured to provide electrical contact between the heat sink and a surface of the conductive enclosure, thereby at least partially shielding the electromagnetic radiation generated by the electronic component.

Claims

1. An apparatus for dissipating heat from an electronic component mounted on a circuit board in an electrically grounded conductive enclosure and for shielding electromagnetic radiation generated by the electronic component, said apparatus comprising:

a heat sink configured to be mounted in thermal contact with said electronic component; and

a spring contact operatively connected to said heat sink and configured to provide electrical contact between said heat sink and the conductive enclosure, thereby at least partially shielding the electromagnetic radiation generated by the electronic component;

wherein said heat sink is mounted on a first side of the circuit board and said spring contact is mounted on a second side of the circuit board by a conductive fastener system extending through the circuit board.

2. The apparatus of claim 1 wherein said spring contact comprises a conductive metallic strip formed with a convex curve along its length and mounted to the circuit board at one or more of its ends.

3. The apparatus of claim 2 wherein both ends of said spring contact are bent under the convex curve and configured to be mounted to the circuit board by said conductive fastener system.

4. The apparatus of claim 3 wherein said ends of said spring contact are mounted to said circuit board by conductive screws in electrical contact with said heat sink.

5. The apparatus of claim 1 further comprising a mounting system for mounting the heat sink on the circuit board.

6. The apparatus of claim 5 wherein the mounting system comprises electrically conductive rails mounted to the circuit board and electrically conductive clips operatively associated with the rails and engaging the heat sink.

7. An apparatus configured to be mounted on a circuit board within an electrically grounded conductive enclosure and adapted to dissipate heat from an electronic component mounted on the circuit board and to shield electromagnetic radiation generated by the electronic component, the apparatus comprising:

a thermally and electrically conductive heat sink configured to be mounted on a first side of the circuit board overlying the electronic component and in thermal contact with the electronic component to dissipate heat generated by the electronic component;

at least one electrically conductive spring contact mounted on a second side of the circuit board, opposite the first side of the circuit board and configured to extend away from the circuit board into frictional contact with the conductive enclosure; and

at least one electrically conductive fastener system configured to extend through the circuit board and engage the spring contact and the heat sink, thereby mechanically mounting the apparatus on the circuit board and grounding the heat sink to shield electromagnetic radiation generated by the electronic component.

8. The apparatus of claim 7 wherein said spring contact comprises a conductive metallic strip formed with a convex curve along its length and mounted to the circuit board at one or more of its ends.

9. The apparatus of claim 8 wherein both ends of said spring contact are bent under the convex curve and configured to be mounted to the circuit board by said conductive fastener system.

10. The apparatus of claim 9 wherein said ends of said conductive spring are mounted to said circuit board by conductive screws in electrical contact with said heat sink.

11. The apparatus of claim 8 wherein said spring contact further comprises a convex curve transverse its length.

12. The apparatus of claim 7 wherein said electronic component is a computer processor.

13. A processor assembly adapted to maintain a safe operating temperature for an electronic component therein and to provide shielding of electromagnetic radiation generated by the electronic component, the processor assembly comprising:

an electrically grounded conductive enclosure;

a circuit board mounted within said conductive enclosure;

an electronic component mounted on a first side of said circuit board and adapted for processing digital signals;

a thermally and electrically conductive heat sink overlying said electronic component and in thermal contact with said electronic component;

an electrically conductive spring contact disposed on a second side of said circuit board and adapted to extend outwardly from said circuit board into frictional contact with said conductive enclosure; and

at least one electrically conductive fastener system extending through said circuit board and engaging said heat sink and said spring contact, thereby mounting said heat sink to said circuit board and grounding said heat sink to provide shielding for electromagnetic radiation generated by said electronic component.

14. The processor assembly of claim 13 wherein said spring contact comprises a conductive metallic strip formed with a convex curve along its length and mounted to the circuit board at one or more of its ends.

15. The processor assembly of claim 14 wherein both ends of said spring contact are bent under the convex curve and configured to be mounted to the circuit board by said conductive fastener system.

16. The processor assembly of claim 13 wherein said fastener system comprises an electrically screw extending through an aperture in said circuit board.

17. A method for dissipating heat from an electronic component and shielding electromagnetic radiation generated by the electronic component, the method comprising the steps of:

positioning an electrically conductive heat sink on a first side of a circuit board overlying an electronic component mounted on the circuit board;

mounting an electrically conductive spring contact on a second side of the circuit board by an electrically conductive fastener system extending through the circuit board;

fastening the heat sink to the electrically conductive fastener system; and

installing the circuit board into a grounded conductive enclosure with the spring contact in frictional contact with the conductive enclosure.

18. The method of claim 17 wherein the engaging step comprises mounting ends of a metallic strip to the circuit board and extending a body of the metallic strip along a convex curve away from the circuit board, thereby providing frictional contact with the electrically grounded conductive enclosure.

19. The method of claim 18 wherein the step of installing the circuit board into a grounded conductive enclosure includes sliding the circuit board into the enclosure in a direction along the length of the spring contact.

20. The method of claim 17 wherein the step of engaging an electrically conductive spring contact with an electrically conductive fastener system comprises mounting a portion of the fastener system to the circuit board and fastening the heat sink to the portion of the fastener system mounted to the circuit board.