Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2000-02-23
2001-11-13
Thompson, Gregory (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C165S080300, C165S185000, C174S016300, C257S719000, C361S710000, C361S715000
Reexamination Certificate
active
06317325
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to circuit pack assemblies used in communication systems and, more specifically, to physical design features that improve the thermal and electromagnetic performance of such circuit pack assemblies.
BACKGROUND OF THE INVENTION
The physical design features of a circuit pack assembly have become important considerations as communications systems evolve to provide more capability using equipment that occupies less space. A common design approach for circuit pack assemblies is to package circuit functions into sub-assemblies or modules, especially in circuit pack assemblies including electronic and optical circuitry. In an effort to provide more functionality in a circuit pack assembly, the size of the modules is being reduced. With the closely packed components within a module, thermal effects as well as electromagnetic radiation therefore become significant concerns. For example, heat generated by components within the modules can become a problem because certain components have maximum operating temperatures. When these temperatures are exceeded, component and ultimately system performance suffers.
Unfortunately, solutions to each of these problems can often be at cross-purposes. For example, one approach for shielding other modules from electromagnetic radiation generated by components is to enclose each module with electrically conductive material to restrict electromagnetic radiation, e.g., to substantially seal the module. However, this solution actually leads to an increased build-up of heat within the module.
Various heat dissipation techniques are also known. One such approach is described in U.S. Pat. No. 5,757,621 wherein a heat sink is attached to a printed circuit board using standoff and spring combinations so that the heat sink makes the appropriate level of thermal contact with the electronic devices on the printed circuit board. Heat sinks having a plurality of vertically and upwardly extending fins which attach to circuit components are also known. Both of these types of heat dissipation arrangements require space on the circuit board assembly for mounting the heat sink as well as additional height clearance above the components. As such, these heat dissipation arrangements are not particularly well-suited in circuit pack assemblies which have substantial space limitations.
SUMMARY OF THE INVENTION
Heat generated by a component in a circuit pack module is dissipated according to the principles of the invention by using a thermally conductive structure as a cover for the module housing for transferring heat from the component and distributing the heat across the entire surface area of the conductive structure. The thermally conductive structure incorporates a cantilevered design and includes a conductive post that maintains contact with and applies a substantially constant amount of force to a top surface of a component in the module. By incorporating a cantilevered design in the module cover, heat dissipation can be achieved using a structure that occupies substantially less space than prior arrangements and which does not damage the component by applying an excessive amount of force.
According to one illustrative embodiment, an apparatus for dissipating heat generated by components housed within modules on a circuit pack includes a first cover member having a deflectable cantilevered region that is defined by a U-shaped slot. A conductive post is mounted or otherwise formed on the underside of the cantilevered region so that the post extends downwardly into the module when the first cover member is secured to the module housing. The conductive post cooperates with a top surface of a component in the module so that heat generated from the component is transferred from the component through the conductive post and distributed along the first cover member. According to another aspect of the invention, interference caused by electromagnetic radiation passing through the U-shaped slot is substantially reduced by disposing a second cover member between the module housing and the first cover member. The second cover member includes an opening that is sized for receiving and passing through the conductive post. The second cover member covers the U-shaped slot in the first cover member to substantially reduce electromagnetic interference caused by one or more components in the module. Accordingly, a solution is provided according to the inventive principles that addresses both thermal and electromagnetic impairments in circuit packs.
REFERENCES:
patent: 5757621 (1998-05-01), Patel
patent: 5812375 (1998-09-01), Caperson
patent: 5903435 (1999-05-01), Hsieh et al.
patent: 6025991 (2000-02-01), Saito
Patel Naresh C.
Sysak Gregory Simeon
Lucent Technologies - Inc.
Murgia Gregory J.
Thompson Gregory
LandOfFree
Apparatus for protecting circuit pack assemblies from... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for protecting circuit pack assemblies from..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for protecting circuit pack assemblies from... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2617402