Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2002-02-05
2004-04-27
Tolin, G. (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C029S890030, C024S458000, C257S719000, C361S719000
Reexamination Certificate
active
06728103
ABSTRACT:
BACKGROUND
1. Field of the Invention
This invention relates generally to chip packaging and particularly to chip packaging including a heat sink.
2. Related Art
An electronic component (e.g., a Central Processing Unit) may generate a significant amount of heat when operating. If not dissipated in time, this heat can degrade performance of the component. To dissipate some of the generated heat, a heat sink device is commonly placed in contact with the component. The heat sink device usually includes a plate and several protrusions from the plate that increase the heat transfer surface area. Sometimes, a fan is used in addition to the heat sink device to assist in heat dissipation.
Currently, a number of methods are used to fasten the heat sink device to the component.
FIG. 1
depicts an exemplary clip
10
disclosed in U.S. Pat. No. 6,153,932, which is incorporated by reference herein. Clip
10
includes a rectangular frame
12
with a hole
14
. Rectangular frame
12
has protruding portions that are designed to extend through a hole, such as side plates
16
and protruding rods
20
. Side plates
16
include a first side plate
16
a
connected to one part of rectangular frame
12
and a second side plate
16
b
connected to a different part of rectangular frame
12
. Each of side plates
16
a
and
16
b
may have fastening hooks
18
a
and
18
b
, respectively. Side plates
16
a
and
16
b
press against two outer edges of a heat sink and a component, and fastening hooks
18
a
and
18
b
snap onto the bottom edges of the component. Protruding rods
20
may include a first protruding rod
20
a
and a second protruding rod
20
b
connected to the sides of frame
10
that do not have a side plate. Clip
10
may also have elastic rods
22
protruding from the inner side walls of frame
10
into hole
14
to provide extra stability and attachment to a heat sink. A person of ordinary skill in the art would understand that other structures for clip
10
are possible. For example, frame
12
and hole
14
may be of any other polygonal shape or even a circular shape. Furthermore, clip
10
may include any fastening device, such as a screw or a snap feature, that can be used to hold a heat sink in a fixed position relative to a component.
However, the currently used methods usually impose at least one limitation on the design of the motherboard or the heat sink. For example, while a screw allows flexibility in the dimensions of the heat sink, it requires that the motherboard have holes. A clip of the sort shown in
FIG. 1
does not require that a motherboard have holes, but requires that heat sink and the component have a width substantially equal to the width of the clip. Such limitations compromise design optimization of heat sink devices.
A heat sink device that provides flexibility in terms of both the size of the heat sink and the motherboard circuitry design is needed.
SUMMARY
In accordance with the present invention, a heat sink extends beyond all outer boundaries of a component cooled by the heat sink. Such an oversized heat sink allows better optimization of heat transfer values than a conventional heat sink, which usually has at least one dimension (e.g. width as noted above) the same as or substantially equal to the corresponding dimension of the component to be cooled. An oversized heat sink attached by a clip to an electronic component not only allows better optimization of heat transfer values but also provides greater flexibility for motherboard circuitry design than a conventional heat sink.
In one embodiment, the heat sink has at least one cutout (or hole) shaped and located so that a portion (hereinafter “protruding portion”) of a clip can extend from one surface of the heat sink and mechanically fasten the electronic component to another (eg., the opposite) surface of the heat sink. The cutout (or hole) may be shaped to fit around the protruding portion. For example, if the protruding portion is a flat plate, the cutout (or hole) through which the protruding portion is inserted may be a rectangular slit. If the protruding portion is a rod, the cutout (or hole) may be circular-shaped. The clip may fasten the heat sink to the component by the protruding portion snapping onto one or more edges of the component. When the clip fastens the heat sink to the component, no hole is needed in the motherboard. In an alternative embodiment, the clip may fasten a component to a heat sink by two or more protruding portions attaching to a motherboard and sandwiching the component between the heat sink and the motherboard. In this alternative embodiment, protruding portions of the clip extend not only through a cutout in the heat sink but also through a cutout in the motherboard, and each snaps onto an edge of the hole in the motherboard.
The clip may include a polygonal (e.g., rectangular) frame with a hole in the middle and a protruding portion on each side of the polygonal frame. Since cutouts (or holes) can be located anywhere on the heat sink, such cutouts (or holes) provide flexibility in terms of the size of the heat sink that can be used with a standard sized clip, and the location on the heat sink where the component is fastened. For example, locating cutouts away from the edges of the heat sink results in a component being fastened near the center of a heat sink. In some embodiments the heat sink extends beyond all outer boundaries of the component, although this is not required in other embodiments.
REFERENCES:
patent: 5130888 (1992-07-01), Moore
patent: 5276585 (1994-01-01), Smithers
patent: 5513073 (1996-04-01), Block et al.
patent: 6061239 (2000-05-01), Blomquist
patent: 6093961 (2000-07-01), McCullough
patent: 6153932 (2000-11-01), Liang
patent: 6219239 (2001-04-01), Mellberg et al.
patent: 6325552 (2001-12-01), Brillhart
patent: 6397941 (2002-06-01), McCullough
patent: 6424530 (2002-07-01), Lee et al.
patent: 6508595 (2003-01-01), Chan et al.
PG pub., US 2002/0108744 A1, Bowman, filed Apr. 19, 202, pub. Aug. 15, 2002.
Calix Networks, Inc.
Silicon Valley Patent & Group LLP
Tolin G.
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