Electrical connectors – Electromagnetic or electrostatic shield – Shielding individually surrounding or interposed between...
Reexamination Certificate
2001-11-27
2002-11-12
Paumen, Gary F. (Department: 2833)
Electrical connectors
Electromagnetic or electrostatic shield
Shielding individually surrounding or interposed between...
C439S939000, C385S092000
Reexamination Certificate
active
06478622
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical transceiver cage, and more particularly to a small form-factor pluggable (SFP) transceiver cage of a high data transfer rate program gigabit interface converter (GBIC).
2. Description of the Related Art
Transceiver modules provide bi-directional transmission of data between an electrical interface and an optical data link. The module receives electrically encoded data signals and converts them into optical signals which are then transmitted over the optical data link. The module also receives optically encoded data signals, converts them into electrical signals, and transmits the electrical signals to the electrical interface.
Normally, the transceiver module is mounted on a printed circuit board (PCB) assembly of a host computer, an input/output system, a peripheral device, or a switch. An SFP transceiver module connects into a metal cage assembly mounted on the PCB. The metal cage generally has two parallel sidewalls, a rectangular top, a rectangular bottom, and front and rear ends. The metal cage provides easy interconnection, and is easily installed on the PCB. The cage functions to dissipate electrostatic buildup, and serves as an electromagnetic shield.
A conventional cage has an entrance portion that is mounted in an opening of an orthogonal panel. A plurality of outwardly projecting grounding tabs adjacent the entrance portion of the cage abuts against edges of the panel that bound the opening. The cage further includes a spring latch at the entrance portion, for contacting an SFP transceiver module. The spring latch is partially received in the opening. A gap exists between the spring latch and an edge of the panel that bounds the opening. In use, electromagnetic interference (EMI) passes through the gap. The cage does not provide adequate protection for the connecting interface from EMI.
In addition, there are no structures specifically for ground contacting a housing of the SFP transceiver module that is engaged in the cage. Furthermore, the cage forms legs for supporting the cage on the PCB, but there is no board locking mechanism to safeguard reflowing of solder during soldering of the cage to the PCB. The cage is liable to disengage from the PCB, causing poor soldering.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an SFP transceiver cage that gives excellent protection from EMI when the cage is mounted to a panel.
Another object of the present invention is to provide an SFP transceiver cage which has a plurality of outward and inward grounding fingers to facilitate grounding and prevent EMI.
A further object of the present invention is to provide an SFP transceiver cage having legs that enable the cage to be locked on a PCB during soldering of the cage to the PCB.
A still further object of the present invention is to provide a sturdy SFP transceiver cage that is easily and inexpensively made essentially from a single metal plate.
To achieve the above objects, an SFP transceiver cage in accordance with a preferred embodiment of the present invention comprises a mainframe and a rectangular grounding device mounted around a front portion of the mainframe. The mainframe includes two sidewalls, a sidewall cover, a top plate, a bottom wall and a rear cover. The mainframe and grounding device are each preferably made from a single piece of metal plate. A plurality of inward grounding fingers are formed on a top, bottom and sides of a front portion of the mainframe. A plurality of outward grounding fingers are formed on a top, bottom and sides of the grounding device, symmetrically opposite the inward grounding fingers of the mainframe. A central outward spring tab is formed at the bottom of the grounding device.
A plurality of compliant legs, needle eye legs and support legs depends from the sidewalls of the mainframe. The compliant and needle eye legs are extended through corresponding holes defined in a PCB. The compliant and needle eye legs prevent the cage from moving relative to the PCB during the course of solder reflowing. The support legs abut a face of the PCB. The support legs serve as standoffs, separating the cage from the PCB to facilitate accurate soldering.
A front portion of the mainframe is mounted in an opening of an orthogonal panel, leaving a gap between the panel and the mainframe. The grounding device is mounted around the front portion of the mainframe, and substantially fits the gap. The outward grounding fingers of the grounding device engage with edges of the panel that surround the opening. The central outward spring tab serves as an EMI shield for any EMI that may pass through a gap existing between the panel and a spring latch of the mainframe. An SFP transceiver module is mounted into the cage having a conductive outer surface. The inward grounding fingers project into the cage contacting the conductive outer surface. The inward and outward grounding fingers and central outward spring tab cooperate to establish multiple electrical paths between the corresponding SFP transceiver module and the mainframe, grounding device and panel.
REFERENCES:
patent: 5178562 (1993-01-01), Ermini
patent: 5317105 (1994-05-01), Weber
patent: 5913698 (1999-06-01), Keng
patent: 6066001 (2000-05-01), Liptak et al.
patent: 6095862 (2000-08-01), Doye et al.
patent: 6139367 (2000-10-01), Yeh
patent: 6227880 (2001-05-01), Zhu et al.
patent: 6231385 (2001-05-01), Kuo
Chung Wei Te
Hon Hai - Precision Ind. Co., Ltd.
Paumen Gary F.
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