The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 17, 2000
Filed:
Nov. 25, 1996
Ralph D Hermansen, Northridge, CA (US);
Richard F Davis, La Habra, CA (US);
E Dean Johnston, Fullerton, CA (US);
Raytheon Company, Lexington, MA (US);
Abstract
An adhesive and method for attaching a heat sink to a printing wiring assembly that provides a thermal path from electronic components on the printing wiring assembly to the heat sink. The adhesive is flexible and accommodates thermal expansion stresses and is readily reworkable. The adhesive comprises a filler material that is disposed between the heat sink and the printing wiring assembly, and an impregnant that impregnates the filler material, which impregnated filler material is cured. The filler material may comprise alumina particles that have a spherical shape. The impregnant comprises a polymer, typically selected from a group of epoxy resins and their curatives that form a flexible material when cured. In practicing the method, a heat sink is positioned adjacent to and spaced apart from a printing wiring assembly to provide an appropriate spacing between them. The periphery of the printing wiring assembly is sealed. A cavity that is formed between the heat sink and the printing wiring assembly is filled with a filler material. The filled assembly is vibrated to maximize packing density of the filler material. The filler material is then impregnated with a flexible epoxy impregnant. The impregnant is then cured to form the flexible adhesive. This produces a structure wherein the heat sink is bonded to the printed wiring assembly.