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Circuit Device With Cooling by Air Directed Toward Fin-Supporting Surface With Fin Height Configured to Maintain Air Velocity As Air Spreads Over Surface

IP.com Disclosure Number: IPCOM000061289D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Chu, RC: AUTHOR

Abstract

A known circuit module has a flat ceramic chip carrier, pins on one side of the chip carrier for electrical connections to a circuit board, and a cap on the other side of the chip carrier to enclose the chips. Heat from the chips flows partly through the cap, and conventionally fins are attached to the cap to transfer the heat to a stream of chilled air. In some systems the air stream is directed to the module at right angles to the surface of the cap. If the fins are in the form of pins, the air spreads evenly along the surface of the cap from the center point where it strikes the surface. If the fins are in the form of two-dimensional strips, the air spreads in opposite directions parallel to the fins. In this module, the fins are higher toward the center point where the air initially strikes the cap.

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Circuit Device With Cooling by Air Directed Toward Fin-Supporting Surface With Fin Height Configured to Maintain Air Velocity As Air Spreads Over Surface

A known circuit module has a flat ceramic chip carrier, pins on one side of the chip carrier for electrical connections to a circuit board, and a cap on the other side of the chip carrier to enclose the chips. Heat from the chips flows partly through the cap, and conventionally fins are attached to the cap to transfer the heat to a stream of chilled air. In some systems the air stream is directed to the module at right angles to the surface of the cap. If the fins are in the form of pins, the air spreads evenly along the surface of the cap from the center point where it strikes the surface. If the fins are in the form of two-dimensional strips, the air spreads in opposite directions parallel to the fins. In this module, the fins are higher toward the center point where the air initially strikes the cap. A tent- shaped shroud confines the air stream to the space occupied by the fins. As the air flows outward from the center point, the height of the air flow path is reduced to maintain a uniform cross section, counteracting the geometric effect that the area of the cap is a function of the square of the radius from the center point. A constant cross section in the air path maintains the air velocity and thereby improves the cooling at the outer fins. With conventional fins of uniform height, the air stream slows a...