Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1999-09-10
2001-03-27
Thompson, Gregory (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C165S080300, C165S185000, C174S016300, C257S707000, C257S713000, C257S719000, C361S710000, C361S720000
Reexamination Certificate
active
06208517
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to temperature control for an electronic device, and, more particularly, to a heat sink for cooling an electronic device.
2. Description of the Related Art
Heat sinks have been widely used to cool electronic devices. Generally, a heat sink operates in a convective heat transfer mode. The heat dissipation ability of the heat sink is directly proportional to its surface area. A common technique for cooling an electronic device is to provide a metal plate on a surface of the device package and mount a heat sink to the metal plate. The metal plate provides a conductive pathway between a die contained within the device package and the heat sink. The thermal efficiency of the coupling from the die to the heat sink greatly affects the ability of the heat sink to cool the die.
In many cases, the cost of the cooling means (e.g., the heat sink) plays a significant role in determining the overall cost of an electronic device. A manufacturer using electronic devices in bulk can appreciate a large savings in terms of tooling and manufacturing costs if the heat sink design can be simplified.
Referring to
FIG. 1
, a prior art heat sink
10
is shown. The heat sink
10
includes a plurality of rectangular folds
12
. The heat sink
10
is coupled to a device package
14
containing a die
16
. A metal plate
18
is provided between the heat sink
10
and the device package
14
. The heat sink
10
clips on to the device package
14
. Detents
20
formed in the device package
14
interface with feet
22
of the heat sink
10
to provide the connection.
This configuration poses several problems. First, the rectangular folds
12
are not centered about the die
16
, thus reducing the efficiency of the heat transfer between the die
16
and the heat sink
10
. Second, the device package is more costly to manufacture due to the need to provide the detents
20
for interfacing with the feet
22
.
A third problem is that because the heat sink
10
is attached to the device package
14
, the possible configurations of the device package
14
are limited, and thus the flexibility of the heat sink
10
is also limited. Because the detents
20
are located on two of the sides of the device package
14
, the heat sink
10
may only be used with a device package
14
having pins
24
on two sides. In other words, the heat sink
10
cannot be used with commonly used packages (not shown) having pins on all four sides. Also, if the dimensions of the device package
14
change, the heat sink
10
must be redesigned to provide the proper interface. These items limit the application of a particular heat sink design to a particular package design, in that any changes in the package
14
would require design and tooling changes for the heat sink
10
. Accordingly, changes in the device package
14
result in costly changes to the heat sink
10
.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
SUMMARY OF THE INVENTION
One aspect of the present invention is seen in a heat sink. The heat sink includes mounting feet, a plurality of folds, and a clip. Each of the folds has a base portion, and the clip couples at least two of the folds together to inhibit fanning in at least a contact region defined by adjacent base portions.
Another aspect of the present invention is seen in an apparatus including a printed circuit board, mounting receptacles on the printed circuit board, a heat sink, and a device package. The heat sink includes feet adapted to interface with the mounting receptacles, a plurality of folds, each having a base portion, and a clip coupling at least two of the folds together to inhibit fanning in at least a contact region defined by adjacent base portions. The device package is coupled to the printed circuit board. The contact region of the heat sink contacts at least a portion of the device package.
Still another aspect of the present invention is seen in an apparatus including a printed circuit board, mounting receptacles on the printed circuit board, a heat sink, and a device package. The heat sink includes feet adapted to interface with the mounting receptacles, a plurality of folds, and a base portion defined between the folds. The device package is coupled to the printed circuit board. The base portion of the heat sink contacts at least a portion of the device package.
REFERENCES:
patent: 2772382 (1956-11-01), Escoffery
patent: 4605058 (1986-08-01), Wilens
patent: 4660123 (1987-04-01), Hermann
patent: 4833569 (1989-05-01), Probst
patent: 4926935 (1990-05-01), Haushalter
patent: 5184281 (1993-02-01), Samarov et al.
patent: 5257162 (1993-10-01), Crafts
patent: 5541811 (1996-07-01), Henningsson et al.
patent: 5717248 (1998-02-01), Neumann et al.
patent: 5786633 (1998-07-01), Wolfgang et al.
patent: 5844313 (1998-12-01), Hoffmann
patent: 5893409 (1999-04-01), Kohler et al.
patent: 6035523 (2000-03-01), McNeil et al.
Brundidge Kevin C.
Cole Toby D.
Prince Stephen T.
Tucker Larry W.
Legerity Inc.
Thompson Gregory
Williams Morgan & Amerson P.C.
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