Variable thickness EMI shield with variable cooling channel size

• US 9,173,331 B2
• Filed: 11/20/2012
• Issued: 10/27/2015
• Est. Priority Date: 11/20/2012
• Status: Active Grant

• Current Assignee: Lenovo International Limited (Lenovo Group Ltd.)
• Original Assignee: Lenovo Enterprise Solutions (Singapore) Pte., Ltd. (Lenovo Group Ltd.)
• Inventors: Gerken, James D., Johnson, David B., Lund, David G., McMillan, Timothy L.
• Primary Examiner(s): BARRERA, RAMON M
• Application Number:
  US13/681,641
• Publication Number:
  US 20140140001A1
• Time in Patent Office: 1,071 Days
• US Class Current: 1/1
• 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 9/00 Screening of apparatus or components against electric or magnetic fields devices for absorbing radiation from an antenna H01Q17/00
• CPC Class Codes: H05K 9/0041 Ventilation panels having provisions for screening

Abstract

An EMI shield for an electronic system enclosure is disclosed. The EMI shield may include an electrically conductive panel with a plurality of air ventilation channels, which has an upstream airflow side and a downstream airflow side. The EMI shield may also include a first air ventilation channel with a first cross-sectional shape having a first cross-sectional area and a first depth. The EMI shield may further include a second air ventilation channel with a second cross-sectional shape, having a cross-sectional area greater than the first cross-sectional area, and a second depth larger than the first depth.

Claims

1. An electromagnetic interference (EMI) shield for an electronic system enclosure, the EMI shield comprising:

an electrically conductive panel comprising an upstream airflow side, a downstream airflow side, and internal surfaces connecting the upstream and the downstream airflow sides, wherein the internal surfaces forming a plurality of first air ventilation channels in the electrically conductive panel and a plurality of second air ventilation channels in the electrically conductive panel,

wherein the internal surfaces of adjacent ones of the plurality of first air ventilation channels are connected by a first section of the electrically conductive panel,

wherein the internal surfaces of adjacent ones of the plurality of second air ventilation channels are connected by a second section of the electrically conductive panel, and

the first and the second sections respectively have first and second uniform thicknesses, wherein the second uniform thickness is greater than the first uniform thickness.

2. The EMI shield according to claim 1, wherein the plurality of first air ventilation channels and the plurality of second air ventilation channels are adapted to attenuate EMI emissions from the electronic system enclosure.

3. The EMI shield according to claim 2, wherein the plurality of second air ventilation channels are electrically conductive ducts having a substantially constant and unrestricted cross-sectional area, and the second section extends outwards from the downstream airflow side of the electrically conductive panel.

4. The EMI shield according to claim 3, wherein the plurality of first air ventilation channels and the plurality of second air ventilation channels air ventilation channels are formed using a pierce and extrude process and have substantially constant and unrestricted cross-sectional areas.

5. The EMI shield according to claim 2, wherein the first air ventilation channels and the plurality of second air ventilation channels air ventilation channels are voids in the electrically conductive panel, having substantially constant and unrestricted cross-sectional areas.

6. The EMI shield according to claim 1, wherein the first air ventilation channels and the plurality of second air ventilation channels air ventilation channels have a substantially constant and unrestricted circular cross-sectional area.

7. The EMI shield according to claim 1, wherein the first air ventilation channels and the plurality of second air ventilation channels air ventilation channels have a substantially constant and unrestricted polygonal cross-sectional area.

8. The EMI shield of claim 1, wherein each of the plurality of first air ventilation channels includes a first cross-sectional shape having a first cross-sectional area and a first depth,

each of the plurality of second air ventilation channels includes a second cross-sectional shape having a cross-sectional area greater than the first cross-sectional area, and a second depth greater than the first depth.

9. The EMI shield according to claim 8, wherein the first cross-sectional shape and the second cross-sectional shape are different.

10. The EMI shield of claim 1, wherein:

the downstream airflow side is disposed in a geometric plane,

a first portion of electronic components of the electronic system is configured to be disposed closer to the geometric plane than a second portion of the electronic components,

the first section of the electrically conductive panel is configured to be disposed between the geometric plane and the first portion of the electronic components along a first geometric line normal to the geometric plane, and

the second section of the electrically conductive panel is configured to be disposed between the geometric plane and the second portion of the electronic components along a second geometric line normal to the geometric plane.

11. The EMI shield of claim 1, wherein the first section of the electrically conductive panel entirely surrounds the plurality of first air ventilation channels and the second section of the electrically conductive panel entirely surrounds the plurality of second air ventilation channels.

12. The EMI shield of claim 1, wherein the first and the second sections of the electrically conductive panel are integral.

13. An electronic system, comprising:

electronic components;

at least one cooling fan generating an airflow; and

an electronic system enclosure disposed around the electronic components, the electronic enclosure includes an electromagnetic interference (EMI) shield, wherein the EMI shield comprises;

an electrically conductive panel comprising an upstream airflow side, a downstream airflow side, and internal surfaces connecting the upstream and the downstream airflow sides, wherein the internal surfaces forming a plurality of first air ventilation channels in the electrically conductive panel and a plurality of second air ventilation channels in the electrically conductive panel,

wherein the internal surfaces of adjacent ones of the plurality of first air ventilation channels are connected by a first section of the electrically conductive panel,

wherein the internal surfaces of adjacent ones of the plurality of second air ventilation channels are connected by a second section of the electrically conductive panel, and

the first and the second sections respectively have first and second uniform thicknesses, wherein the second uniform thickness is greater than the first uniform thickness.

14. The electronic system of claim 13, wherein the plurality of first air ventilation channels and the plurality of second air ventilation channels are adapted to attenuate EMI emissions from the electronic system enclosure.

15. The electronic system of claim 14, wherein the first uniform thickness and the second uniform thickness provide accommodation for proximity of components to the electrically conductive panel.

17. The electronic system of claim 13, wherein the plurality of air ventilation channels are oriented to extend away from the downward side of the electrically conductive panel in a direction approximately normal to the electrically conductive panel.

18. The electronic system of claim 13, wherein the plurality of air ventilation channels are oriented to extend away from the downward side of the electrically conductive panel in a direction significantly different than normal to the electrically conductive panel.

19. The electronic system of claim 13, wherein

the downstream airflow side is disposed in a geometric plane,

a first portion of electronic components of the electronic system is disposed closer to the geometric plane than a second portion of the electronic components,

the first section of the electrically conductive panel is disposed between the geometric plane and the first portion of the electronic components along a first geometric line normal to the geometric plane, and

the second section of the electrically conductive panel is disposed between the geometric plane and the second portion of the electronic components along a second geometric line normal to the geometric plane.

16. The electronic system of 15, wherein the first uniform thickness is adapted to allow a component of an electronic system to extend outward from the electronic system enclosure through the EMI shield.