Northern Telecom Limited

Roman Katchmar

Clifford D Read

John S Moss

Hugh M Collins

Hasler R Hayes

John B Drayton

David J Pell

Tristano F Nicoletta

Making an assembly of a printed circuit board structure and heat sink structure by locating a thermally conductive surface release agent upon a side of one of the structures and causing a flowable thermally conductive material to flow through a hole in the heat sink and lie between the release agent and the other structure. The thermally conductive material lies in heat conductive contact with the release agent and with the other structure and in alignment with an electronic component which is to be cooled upon the board. The release agent ensures easy release of the printed circuit board structure from the heat sink structure for disassembly purposes. An assembly of the two structures is also covered.

Printed circuit board and heat sink arrangement

A method of making a printed circuit board and heat sink structure by initially providing the board with a heat conductive layer oh each of its two sides, the two conductive layers thermally interconnected by heat conductive material extending through holes in the board. An electronic component is mounted spaced apart from the conductive layer on one side of the board and is thermally connected to that layer by a thermally conductive viscous substance injected through a hole from the other side of the board. The viscous material flows in a reverse direction through other holes in the board. A heat sink is then attached by thermally conductive material to the conductive layer on the other side of the board. A method is also included of injecting a thermally conductive curable resin between an electronic component and a printed circuit board with a release agent between the component and the resin. After cooling the resin at sufficiently high temperature for it to be in contact with the release agent, the cured resin cools and shrinks away from the component. Subsequent heating of the resin expands it into heat conductive engagement with the component for quicker release of heat therefrom.

Methods of making printed circuit boards and heat sink structures

Making a heat sink and printed circuit board assembly by providing a heat exchange element on the heat sink which lies in heat exchange contact with the heat sink and passes therethrough. After locating the board and heat sink in relative positions apart and with the heat exchange element aligned with an electronic component on the board, a settable thermally conductive compound is injected through a hole in the heat exchange element to bond it to the electrical component. The heat sink is detachable from the heat exchange element to expose the side of the board carrying the components so that maintenance or repair may be performed. Subsequently the heat sink is returned into its position in the assembly.

Printed circuit board and heat sink assembly in which heat conductive elements are provided to distribute heat across the board before transferring heat into the heat sink. Also in other structures, heat is conducted directly into a heat sink from surface mount components while bypassing the board.

Printed circuit boards and heat sink structures

Electronic unit of printed circuit board with electronic components on one side and its other side in heat conducting contact with a heat sink enables the electronic components to be sealed from ambient atmosphere and thus unpackaged chips may be used. The units are mountable in a support frame with air cooling passages of the heat sinks extending vertically for convected cooling air. In each unit, a resistor network may extend into a cavity formed in a heat exchange rib and an electronic chip, perhaps unpackaged in the sealed environment, may be in heat conductive relationship with the heat sink.

Electronic unit

Electronic module of printed circuit board with electronic components on one side and its other side in heat conducting contact with a heat sink enables the electronic components to be sealed from ambient atmosphere and thus unpackaged chips may be used. The modules are mountable in a support frame with air cooling passages of the heat sinks extending vertically for convected cooling air. In each module, a resistor network may extend into a cavity formed in a heat exchange rib and an electronic chip, perhaps unpackaged in the sealed environment, may be in heat conductive relationship with the heat sink.

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Ottawa, Canada

Roman Katchmar