Browse Prior Art Database

High Density Circular Contact

IP.com Disclosure Number: IPCOM000106942D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 4 page(s) / 120K

Publishing Venue

IBM

Related People

Fiacco, V: AUTHOR [+5]

Abstract

In any application requiring a 10 way machine, due to limitations on substrate size, it is necessary to incorporate an increased contact density in the TCM (Thermally Conductive Module) connector. By introducing a smaller contact, it is possible to provide better density in this area array connector.

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This is the abbreviated version, containing approximately 52% of the total text.

High Density Circular Contact

       In any application requiring a 10 way machine, due to
limitations on substrate size, it is necessary to incorporate an
increased contact density in the TCM (Thermally Conductive Module)
connector.  By introducing a smaller contact, it is possible to
provide better density in this area array connector.

      Rectangular contacts, as presently used, do not readily lend
themselves to significant reduction in size.  In this article, a
contact capable of being mounted on much closer centers is outlined.
This approach provides a top mating contact with reasonable engaging
forces which will enable the use of much higher contact density.
With the introduction of a mixed grid interstitial harcon array,
densities of 220 contacts per square inch are attainable. To provide
even better density, the contact defined here can provide densities
approaching 400 contacts per square inch. Such a contact appears in
Fig. 1.

      The use of a circular contact as shown in Fig. 1 can provide
improved density with commensurate reliability to that presently
being achieved with conventional contacts. Redundant electrical
contact is provided through two opposed cantilever beams which are
designed to provide normal force in the range of 30 to 80 grams.
Using the contact as shown with the cantilever root at the contact
entry, engaging forces are reduced due to a more advantageous pin
entry with respect to the contact leaf. The design shown is readily
adaptable to conventional die techniques, in that the contact can be
formed on reels having the selvage strip offset from the center line
as in Fig. 2.  This enables contact assembly on the close density
required by this application (Contact pitch on reel is 2.4 mm, after
assembly to board pitch is 1.2 mm.)  A surface mount foot as shown
provides a means of assembly which enhances board wiring due to the
elimination of the plated through holes required for conventional
wave-soldered designs.  The foot shown can be provided in a
solder-plated version which, when mated with similar metallurgy on
the board pad, can be attached using infrared or vapor phase heating
techni...