Browse Prior Art Database

HOT MELT ADHESIVE INTERCONNECT AND ALIGNMENT SYSTEM

IP.com Disclosure Number: IPCOM000005612D
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2001-Oct-19
Document File: 1 page(s) / 57K

Publishing Venue

Motorola

Related People

Frank Juskey: AUTHOR [+2]

Abstract

State-of-the-art electronics assemblies use a conductive hot melt adhesive screened on a flexible mylar or kapton substrate to make board-to-board or board-to-LCD interconnections. While these systems enjoy an order of magnitude reduction in height over standard elastomeric interconnect systems, they do have two ma- jor draw-backs which are, difficulty in alignment and poor peel strength characteristic of hot melt adhesives.

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MO7VROLA Technical Developments Volume 6 October 1986

HOT MELT ADHESIVE INTERCONNECT AND ALIGNMENT SYSTEM

by Frank Juskey and Dale Dorinski

   State-of-the-art electronics assemblies use a conductive hot melt adhesive screened on a flexible mylar or kapton substrate to make board-to-board or board-to-LCD interconnections. While these systems enjoy an order of magnitude reduction in height over standard elastomeric interconnect systems, they do have two ma- jor draw-backs which are, difficulty in alignment and poor peel strength characteristic of hot melt adhesives.

   These draw-backs can be overcome by the use of an alignment pin which can be placed in tooling holes in both the board and the flex interconnect. During the flex-to-board bonding operation the pin aligns and holds the parts in proper orientation. This is accomplished by the use of a thermoplastic such as polyethylene or polypropylene that has been preformed into a flat headed pin. The pin (1) is inserted into the board (2) with the flat head on the bottom. The flex circuit (3) with the conductive hot melt adhesive (4) is placed over the protruding shaft of the pin, aligning the flex conductors (5) to the board conductors (6) thus eliminating the necessity of visually aligning the two substrates.

   In addition to providing alignment, the end of the thermoplastic pin melts and flows during the bonding cycle, providing enhanced peel strength. This extra bond strength is provided at the short overlapping edge o...