Passive cooling and EMI shielding system

Patent metadata

Field	Value
Publication number	US-9513675-B2
Application number	US-201414463566-A
Country	US
Kind code	B2
Filing date	Aug 19, 2014
Priority date	May 5, 2011
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

An electronics enclosure is disclosed that provides passive cooling of electronic components while reducing electromagnetic interference (EMI) emissions. The electronics enclosure includes an electronics assembly with at least one electronic component and a heat sink coupled to the electronics assembly. The heat sink has a base portion configured to thermally couple to the at least one electronic component when the heat sink is coupled to the electronic assembly. The electronics enclosure also includes a conductive enclosure forming an enclosed volume around the electronics assembly. The enclosure has a first opening configured to fit around the heat sink and at least one second opening. All non-conductive passages from the volume to the external environment have at least one cross-sectional opening having a continuous conductive perimeter with a maximum linear length within the opening of less than one quarter wavelength of a determined maximum shielding frequency.

First claim

What is claimed is:

1. An electronics enclosure for providing passive cooling of electronic components while reducing electromagnetic interference (EMI) emissions, the electronics enclosure comprising:
an electronics assembly comprising a planar substrate and at least one electronic component, the planar substrate including a conductive strip around a portion of a periphery of an upper surface of the planar substrate;
a heat sink coupled to the electronics assembly, the heat sink comprising a base portion configured to thermally couple to the at least one electronic component when the heat sink is coupled to the electronic assembly; and
a conductive enclosure forming an enclosed volume around the electronics assembly, the enclosure comprising a first opening configured to fit around the heat sink, at least one second opening formed in the conductive enclosure spaced from the first opening, and a flange configured to mate with the conductive strip when the conductive enclosure is coupled with the planar substrate, wherein an air flow path extends through the first opening to the at least one second opening when the conductive enclosure encloses the at least one electronic component.

2. The electronics enclosure of claim 1 , wherein a width of the base portion is less than a width of the planar substrate.

3. The electronics enclosure of claim 1 , wherein the base portion defines a slot, the heat sink comprising a heat pipe disposed in the slot.

4. The electronics enclosure of claim 3 , wherein the heat pipe is flush with a bottom surface of the heat sink.

5. The electronics enclosure of claim 1 , wherein the heat sink comprises a plurality of fins, and the conductive enclosure comprises an edge, the edge conductively coupled to at least one of the plurality of fins.

6. The electronics enclosure of claim 5 , wherein the edge is conductively coupled to all of the plurality of fins.

7. The electronics enclosure of claim 5 , wherein the edge is conductively coupled to every other fin.

8. The electronics enclosure of claim 5 , wherein the edge is conductively coupled to fins separated by a distance, the distance being less than a linear distance equal to a desired cutoff frequency.

9. The electronics enclosure of claim 1 , wherein the heat sink comprises a box thermally coupled to the base portion.

10. The electronics enclosure of claim 9 , wherein the box comprises a plurality of passages.

11. The electronics enclosure of claim 10 , wherein the plurality of passages are rectangular.

12. The electronics enclosure of claim 11 , wherein the box comprises a plurality of intersecting sheets of conductive material that forms the plurality of rectangular passages.

13. The electronics enclosure of claim 10 , wherein the plurality of passages are circular.

14. The electronics enclosure of claim 10 , wherein the plurality of passages are L-shaped.

15. The electronics enclosure of claim 10 , wherein the plurality of passages extend from a first end of the box to a second end of the box.

16. The electronics enclosure of claim 10 , wherein the plurality of passages extend transversely to a width of the base portion.

17. An electronics enclosure for providing passive cooling of electronic components while reducing electromagnetic interference (EMI) emissions, the electronics enclosure comprising:
an electronics assembly comprising a planar substrate and at least one electronic component, the planar substrate including a conductive strip around a portion of a periphery of an upper surface of the planar substrate;
a heat sink coupled to the electronics assembly, the heat sink comprising a base portion configured to thermally couple to the at least one electronic component when the heat sink is coupled to the electronic assembly, the heat sink comprising a conductive portion conductively coupled to the base portion, the conductive portion comprising a plurality of passages; and
a conductive enclosure forming an enclosed volume around the electronics assembly, the enclosure comprising a first opening configured to fit around the heat sink, at least one second opening formed in the conductive enclosure spaced from the first opening, and a flange configured to mate with the conductive strip when the conductive enclosure is coupled with the planar substrate, wherein an air flow path extends through the first opening to the at least one second opening when the conductive enclosure encloses the at least one electronic component.

18. The electronics enclosure of claim 17 , wherein the plurality of passages are open through the first opening.

19. An automatic dispensing machine comprising:
a display comprising a top and a base; and
an electronics enclosure for providing passive cooling of electronic components while reducing electromagnetic interference (EMI) emissions, the electronics enclosure comprising:
an electronics assembly comprising a planar substrate and at least one electronic component, the planar substrate including a conductive strip around a portion of a periphery of an upper surface of the planar substrate;
a heat sink coupled to the electronics assembly, the heat sink comprising a base portion configured to thermally couple to the at least one electronic component when the heat sink is coupled to the electronic assembly; and
a conductive enclosure forming an enclosed volume around the electronics assembly, the enclosure comprising a first opening configured to fit around the heat sink, at least one second opening formed in the conductive enclosure spaced from the first opening, and a flange configured to mate with the conductive strip when the conductive enclosure is coupled with the planar substrate, the at least one second opening located at the top of the display, the first opening located at the base of the display, wherein an air flow path extends through the first opening to the at least one second opening when the conductive enclosure encloses the at least one electronic component.

20. The electronics enclosure of claim 19 , further comprising an internal space under the display, the first opening open to the internal space.

Assignees

• Carefusion 303 Inc

Inventors

• Nicol David H
• Joyce Michael Dugan
• Burgess Brendan

Classifications

• H05K7/20336

  Heat pipes, e.g. wicks or capillary pumps · CPC title

• Y10T29/49117

  Conductor or circuit manufacturing · CPC title

• G16H20/10

  relating to drugs or medications, e.g. for ensuring correct administration to patients · CPC title

• H05K7/2039

  characterised by the heat transfer by conduction from the heat generating element to a dissipating body (arrangements for increasing/decreasing heat-transfer, e.g. fins details, F28F13/00) · CPC title

• H05K7/20127 Primary

  Natural convection · CPC title