0
Research Papers

Digital Moiré Subtraction Interferometry (DMS) for Electronics Cooling Applications in Enclosures

[+] Author and Article Information
David Newport

Department of Mechanical and Aeronautical Engineering, Stokes Institute, University of Limerick, Limerick, Irelanddavid.newport@ul.ie

Colin Forno

Institute for Health and Consumer Protection, European Commission DG-Joint Research Centre, 21020 Ispra (VA), Italyc.forno@ntworld.com

Maurice Whelan

Department of Mechanical and Aeronautical Engineering, Stokes Institute, University of Limerick, Limerick, Ireland; Institute for Health and Consumer Protection, European Commission DG-Joint Research Centre, 21020 Ispra (VA), Italymaurice.whelan@ec.europa.eu

J. Electron. Packag 132(3), 031001 (Sep 08, 2010) (9 pages) doi:10.1115/1.4002161 History: Received February 09, 2006; Revised June 02, 2010; Published September 08, 2010; Online September 08, 2010

Optical noninvasive temperature measurement techniques, such as interferometry, are particularly advantageous in obtaining temperature information noninvasively from enclosed low velocity flows induced by thermal sources, as commonly arise in electronic systems. The single greatest restriction in the application of interferometry as a standard measurement methodology has been the enormous cost associated with the optical equipment required. This cost is due to the quality of the optics required, which exhibits an exponential dependence on size. Digital Moiré subtraction is a technique, which removes the restriction on the use of high quality optics, thereby, enabling reasonably large fields of view. In this paper, a digital Moiré subtraction interferometer configuration is presented with a 140 mm field of view. First, the ability of the interferometer to accurately measure the free convection temperature field about an isothermal horizontal cylinder is examined through a comparison with measurements from literature using classical interferometry. The technique is then applied to the thermal interaction between 2D components representing BGAs mounted on a vertical printed circuit board (PCB). Qualitative and quantitative evaluation of the interferograms show the significant influence of in-plane PCB conductivity on the temperature field about the PCB. The spacing to length ratio above, which upstream components on a PCB experience enhanced cooling, is reduced from 4 to 3 for a PCB with a high effective in-plane conductivity (15W/mK).

FIGURES IN THIS ARTICLE
<>
Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Obtaining a digital Moiré subtraction interferogram through a poor optical quality plastic sheet. The fringes introduced by the poor quality of the sheet, shown on the left, are used as the Moiré pattern and subtracted to show the fringes on the right. These fringes were introduced by tilting one of the mirrors.

Grahic Jump Location
Figure 2

Schematic plan view of interferometer

Grahic Jump Location
Figure 3

Front view photograph of interferometer

Grahic Jump Location
Figure 4

Rear view photograph of interferometer

Grahic Jump Location
Figure 5

Digital Moiré subtraction interferograms of an isothermal horizontal cylinder at two different Rayleigh numbers

Grahic Jump Location
Figure 6

Digital Moiré subtraction interferograms of an isothermal horizontal cylinder at two different Rayleigh numbers

Grahic Jump Location
Figure 7

Reproducibility of the dimensionless temperature distribution about the horizontal isothermal cylinder at Ra=6.80×103

Grahic Jump Location
Figure 8

Reproducibility of the dimensionless temperature distribution about the horizontal isothermal cylinder at Ra=1.04×104

Grahic Jump Location
Figure 9

Interferograms for different powered component configurations, dissipating 3 W, on the high conductivity PCB, with an effective in-plane conductivity of 15.13 W/m K

Grahic Jump Location
Figure 10

Interferograms for different powered component configurations, dissipating 3 W, on the low conductivity PCB, with an effective in-plane conductivity of 1.48 W/m K

Grahic Jump Location
Figure 11

Dimensionless temperature distributions at various locations along both boards for different powering combinations, with each component dissipating 3 W

Grahic Jump Location
Figure 12

Dimensionless temperature distributions at various locations along both boards for different powering combinations with each component dissipating 9 W

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In