Electricity: conductors and insulators – Anti-inductive structures – Conductor transposition
Reexamination Certificate
2001-12-20
2003-08-26
Ngo, Hung V. (Department: 2831)
Electricity: conductors and insulators
Anti-inductive structures
Conductor transposition
C454S184000
Reexamination Certificate
active
06610922
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates in general to electromagnetic shielding for electronic components, and more particularly to an apparatus for securing an electromagnetic shield in a conductive casing.
BACKGROUND OF THE INVENTION
As demand for higher speed telecommunication and networking equipment increases, devices must include faster processors, system clocks, and busses to meet these performance demands. As the speed of components increases, the components produce more intense and higher frequency electromagnetic (EM) emissions. In order to comply with regulatory standards and prevent interference with the operation of other devices, these EM emissions must be substantially contained. The emissions may be contained by a conductive casing, but apertures in the conductive casing are necessary to allow sufficient air flow to cool electronic components during operation. As long as apertures are sufficiently small, the conductive casing can still contain electromagnetic emissions from the components. However, as the frequency of electromagnetic emissions increases, the aperture size must be reduced. As a result, it can become difficult to block electromagnetic emissions while still allowing sufficient air flow.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, the disadvantages and problems associated with shielding against high frequency electromagnetic emissions have been substantially reduced or eliminated. In particular, the need for screws, conductive gaskets, conductive glue, and other equipment to secure electromagnetic shields into apertures has been greatly reduced.
In one embodiment, an apparatus for securing an electromagnetic shield includes a conductive frame, first spring devices along a first edge of the conductive frame that secure an electromagnetic shield in the frame and couple the electromagnetic shield to the frame electrically, and second spring devices along a second edge of the frame that secure the conductive frame in an aperture in a conductive casing and couple the conductive frame to the casing electrically. The conductive frame may be formed from a flexible metal alloy plated with a conductive, corrosion-resistant material. The frame may also include an inner lip for securing the electromagnetic shield in position, and an outer lip for securing the frame in an aperture through a conductive casing.
In another embodiment of the present invention, an electromagnetic shielding apparatus includes a conductive frame, an electromagnetic shield made of conductive material formed into cells, and spring devices along a first edge of the frame to secure the electromagnetic shield within the frame and couple the frame to the shield electrically. The frame may be formed from a flexible metal alloy and plated with a conductive, corrosion-resistant material. In a particular embodiment, the electromagnetic shield is formed from aluminum or steel, and each cell of the electromagnetic shield is approximately 0.08 inches across.
Important technical advantages of certain embodiments of the present invention include electromagnetic shielding that allows sufficient air flow to cool shielded components. In particular, certain embodiments of the present invention allow shielding of an aperture in a conductive casing while allowing air flow through the aperture. This allows shielding of high frequency electromagnetic emissions without substantially interfering with air flow.
Another important technical advantage includes using flexible metal in the conductive frame. Using flexible metal allows the frame to be fitted into apertures more easily. Since the material of the frame is flexible, portions of the frame can be formed into spring devices. Since the spring devices can be made integral to the frame, the frame can be manufactured as a single piece, making the device even more easy to manufacture and use.
Particular embodiments of the present invention may include some, all, or none of the technical advantages described above. Additional technical advantages of various embodiments of the invention will be readily apparent to one skilled in the art. The technical advantages of the present invention can be better understood by reference to the following figures, description, and claims.
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Creekmore Norman L.
Kozak Frederic M.
Twiss Robert G.
Baker & Botts L.L.P.
Cisco Technology Inc.
Ngo Hung V.
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