News Column

Researchers Submit Patent Application, "Resilient Adherent EMI Shielding Member", for Approval

August 6, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventor HIRSCHY, Christopher D. (Conway, AR), filed on January 11, 2013, was made available online on July 24, 2014.

The patent's assignee is Molex Incorporated.

News editors obtained the following quote from the background information supplied by the inventors: "The Present Disclosure relates generally to structures associated with electronic modules for reducing electromagnetic interference (EMI) radiation therefrom, and more particularly to a cost-effective and easily applied shielding member for use with a shielding cage housing a connector on a printed circuit board and which receives an electronic module therein, that mates to the connector.

"Electronic modules are used to connect various electronic devices together. Such modules are usually terminated to opposing ends of a cable to define a cable assembly that is used to interconnect a server to a router, for example. Such modules may incorporate fiber optic, electrical or combined transceivers formed in the shape of a plug and the plugs are received within receptacles that are disposed within electrical equipment. These receptacles can include metal or die cast guide frames or sheet metal or metalized cages to form a conductive receptacle. Such a receptacle commonly includes opposing top and bottom walls, opposing side walls joining the top and bottom walls together to define a four walled enclosure. A rear wall typically interconnects the side walls and top walls together with an opening formed in the bottom wall so that the receptacle can be mounted to a circuit board over a connector, which is also mounted to the circuit board.

"These modules are often constructed in accordance with various standards that dictate the size and compatibility so that modules can be used interchangeably within a standard. These standards are now envisioning data transfer rates of 2.5 gigabytes per second (GBPS) and upwards of 10 GBPS or greater. At such high data transfer speeds, the modules generate electromagnetic energy. As the amount of such energy increases, this energy passes through gaps present in the receptacle/cage to an extent that it generates EMI that adversely affects the transmission of data signals through the module, and the adjacent modules of the associated electronic equipment to which it is connected. It is therefore desirable to shield data signals from EMI to the entire extent of the receptacle.

"In most cage-style receptacles, conductive gaskets are utilized to provide EMI shielding. These gaskets may include pliable structures, such as that described in U.S. Pat. No. 6,752,663, the content of which is hereby incorporated herein by reference in its entirety, which describes a conductive foam gasket that extends along three sides of the receptacle bottom opening. Or, as also described in the '633 Patent, gaskets may be formed as a separate metal spring that is positioned along a fourth side of the receptacle/cage opening. Such metal springs are usually stamped and formed into gasket structures that have a plurality of thin metal spring fingers. These metal spring gaskets are applied to the receptacle/cages around openings where the are mounted to the circuit board or where an opening is present that defines an insertion passage for an electronic module.

"Shielding cages are being provided with more openings formed in the receptacle/cage walls where the cage is stamped and formed to provide a module stop, a heat sink attachment clip, a module retainer, or lock and the like. Metal spring gaskets can cost more than a dollar to manufacture and apply and the use of them to contain EMI at these type of openings is difficult due to the locations of the openings, as well as difficulty in attaching them to the cage so they can cover the openings in an effective EMI shielding manner. Accordingly, a need exists for a cost-effective EMI shielding gasket that can be used in association with receptacle/cage openings and which can be applied thereto either manually or robotically at minimal cost."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventor's summary information for this patent application: "In accordance with an exemplary embodiment of the Present Disclosure, an improved EMI shielding gasket is provided for use in sealing off openings formed in receptacles and/or cages. Such receptacles usually take the form of a rectangular, hollow enclosure defined by a plurality of walls. Openings are formed in the receptacle walls to form various structural features, such as insertion stops for electronic modules, anchor slips for heat sinks, receptacle keys, receptacle latching members and the like. All of these openings have in common the fact that for the most part, they are defined by a minimum of three sides and most often four or more sides. Typically, the openings are stamped in a single plane of the receptacle or cage body such that part of the cage forms a boundary around the opening, or alternatively, they may extend within two, adjoining planes.

"A shield member in the form of an adhesive-backed conductive label or pad is provided having a general overall diameter of the corresponding cage opening. The shield member may be formed of a first layer of a conductive, pliable material such as a foam or it may include a layer of a static-dissipative material to which an adhesive layer is attached. Importantly, the labels have at least an initial planar configuration that permits them to be applied to openings in one plane of the cage, but the planar configuration preferably has an extent that permits the label to be folded into contact with a second plane of the cage that is adjoining the cage one plane. Also, it is preferred that the label be substantially impervious, that is air-tight, so that the labels may be easily acquired by a vacuum pick up device and discharged by the same during application. The planar nature of the labels makes it easy for optical recognition technology to be used in their application to the cage openings. Preferably, the shield member has a thickness of at least about 0.008 to 0.015 inches and it may exceed those dimensions. It is stable enough that it can be moved by way of the vacuum pick-up manner described above without compromising the planar nature of the shield member, such as by wrinkling

BRIEF DESCRIPTION OF THE FIGURES

"The organization and manner of the structure and operation of the Present Disclosure, together with further objects and advantages thereof, may best be understood by reference to the following Detailed Description, taken in connection with the accompanying Figures, wherein like reference numerals identify like elements, and in which:

"FIG. 1 is a perspective view of a module-receiving receptacle, or cage, with the cage body illustrated as having a plurality of openings disposed therein;

"FIG. 2 is the same view as FIG. 1, but with a like plurality of pliable EMI shield members constructed in accordance with the principles of the Present Disclosure applied over the openings;

"FIG. 3 is a partial detail view of the cage of FIG. 1, but with the shield members shown removed and spaced apart therefrom in order to show the relative dimensions of the cage openings and the pliable shield members;

"FIG. 4 is a diagrammatic view of a configuration of a cage opening and of the configuration of an associated pliable shield member intended for covering the cage opening;

"FIG. 5A is a sectional view of a shield member of the Present Disclosure having three layers;

"FIG. 5B is a sectional view of another embodiment of a shield member of the Present Disclosure which has two layers; and

"FIG. 6 is a perspective view of a shield member of the Present Disclosure intended for covering a cage opening that extends in two different planes."

For additional information on this patent application, see: HIRSCHY, Christopher D. Resilient Adherent EMI Shielding Member. Filed January 11, 2013 and posted July 24, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=4934&p=99&f=G&l=50&d=PG01&S1=20140717.PD.&OS=PD/20140717&RS=PD/20140717

Keywords for this news article include: Electronics, Circuit Board, Electromagnet, Molex Incorporated.

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Source: Electronics Newsweekly


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