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Fan Opening Pattern for a Personal Computer

IP.com Disclosure Number: IPCOM000115188D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Barina, RM: AUTHOR [+4]

Abstract

Disclosed is a fan grille pattern for a personal computer (PC) chassis that provides the necessary electromagnetic shielding of the system internal electronics to meet IBM* Corp. and external agency personal computer electromagnetic compatibility (EMC) radiated requirements. It also provides an optimum grille pattern resulting in improved aero-acoustic performance. The following are the unique features of the PC fan opening design. 1. All linear dimensions of the fan opening pattern are less than 1/20 a wavelength of the highest electromagnetic frequency to be contained in the PC mechanical enclosure. This provides the necessary electromagnetic shielding of the system internal electronics to meet IBM Corp. and external agency personal computer EMC radiated requirements. 2.

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Fan Opening Pattern for a Personal Computer

      Disclosed is a fan grille pattern for a personal computer (PC)
chassis that provides the necessary electromagnetic shielding of the
system internal electronics to meet IBM* Corp. and external agency
personal computer electromagnetic compatibility (EMC) radiated
requirements.  It also provides an optimum grille pattern resulting
in improved aero-acoustic performance.  The following are the unique
features of the PC fan opening design.
  1.  All linear dimensions of the fan opening pattern are less than
       1/20 a wavelength of the highest electromagnetic frequency to
be
       contained in the PC mechanical enclosure.  This provides the
       necessary electromagnetic shielding of the system internal
       electronics to meet IBM Corp.  and external agency personal
       computer EMC radiated requirements.
  2.  Dimensions in the fan opening pattern are varied.  This reduces
       resonances which occur when multiple same length openings
exist
       and creates an even level of electromagnetic field attenuation
       over the entire desired frequency range.
  3.  Integrating the fan opening pattern into the PC mechanical
       package maintains the grounding and shielding integrity up to
and
       across the attenuation and also provides protection to
internal
       electronics from potential electrostatic discharge.
  4.  The fan g...