Browse Prior Art Database

Flexible Circuit Attachment of Optical Subassembly to Chip Carrier

IP.com Disclosure Number: IPCOM000106545D
Original Publication Date: 1993-Nov-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Danovitch, BD: AUTHOR [+5]

Abstract

Disclosed are methods to effectively stiffen a flexible circuit (flex) near weak solder joints. This stiffening will eliminate any motion of the flex at the sol joints by transferring the movement to a more elastic section of the flex. Two methods of stiffening are used simultaneously to achieve the desired effect, and both are described below.

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Flexible Circuit Attachment of Optical Subassembly to Chip Carrier

      Disclosed are methods to effectively stiffen a flexible circuit
(flex) near weak solder joints.  This stiffening will eliminate any
motion of the flex at the sol joints by transferring the movement to
a more elastic section of the flex.  Two methods of stiffening are
used simultaneously to achieve the desired effect, and both are
described below.

1.  Gasket clamp assembly.  The disclosed method is illustrated in
    Fig. 1.  A gasket made from a durable non-setting silicone
    material (Dow Corning Silastic 745U) is assembled onto the flex,
    thereby effectively clamping down on flex to stiffen flex near
    the solder joint.

    Under the flex is an optional plastic pad to control the
    capacitance between the flex and the electrically grounded
    housing.

2.  Posts on housing mating with undersized hole in flex.  The
    disclosed method is illustrated in Fig. 2, which represents a
    plane view of a module assembly without a cover.  Prior to solder
    reflow of the flex, the flex is placed over two posts near the
    solder joint.

    The posts are designed to be slightly over-sized compared to the
    provisions in the flex.  The provisions in the flex are closely
    toleranced etched copper holes.  During assembly of the flex onto
    the posts, the copper in the holes are deformed, ensuring a tight
    fit.

    A second ben...