Patent Application
20220393404
The techniques described herein relate generally to interconnection systems and more specifically to designs for reducing electromagnetic interference and/or improving high frequency performance in electronic devices.
Electronic devices are often connected, whether to enable those devices to communicate over networks or because those devices form part of the network. For example, servers are often connected to a network to exchange data with other servers or end user devices. Similarly, routers and switches are often connected to form a network or connected to devices that are using the network to exchange data.
Often such connections are made through I/O connectors inside the devices mated with plugs terminating cables that are routed between the electronic devices. The I/O connectors are configured as receptacles that mount to a printed circuit board and mate with a plug. The receptacles may be mounted near an edge of a printed circuit board to which components forming the electronic device are attached. That edge may be next to a panel of an enclosure holding the printed circuit board and possibly other subassemblies that constitute the electronic device.
To enable a plug to be inserted into a receptacle, the panel may have openings through which a plug may be inserted to mate with the receptacle. An opening in the panel, however, can allow electromagnetic radiation to escape from the enclosure or, conversely, for radiation to enter the enclosure through the panel. Radiation passing through a panel of electronic device can lead to undesirable interference between electronic devices or even between different portions of the same electronic device.
To reduce electromagnetic interference (EMI), receptacle connectors are often enclosed in a grounded metal structure, referred to as a cage. The cage may have one or more channels, each shaped to receive a plug and aligned with both a panel opening and a mating interface of a receptacle. The plug may be inserted through the panel opening into the channel, such that the plug and receptacle mate inside the cage. In this state, the cage blocks radiation from inside the device from reaching the panel opening. Further, the plug may have a conductive exterior that is also grounded, which blocks radiation from the plug or receptacle from exiting the cage through the channel.
To enhance the effectiveness of the cage and plug at blocking electromagnetic radiation, one or more components that act as electromagnetic seals may be used. A conductive gasket may be positioned between the cage and the perimeter of the panel opening to reduce the radiation escaping from any opening between the cage and the panel. Additionally, spring fingers may be mounted in the mouth of the channel. These spring fingers may be biased outwards from the channel walls to make contact with the conductive exterior of the plug, blocking the openings between the plug and the cage.
In this way, a substantial amount of radiation that might otherwise escape the enclosure through the panel opening is blocked by the cage and plug. Radiation that might enter the enclosure is likewise blocked, which also reduces EMI.
The effectiveness of a component, such as a cage or spring fingers, in blocking radiation from passing through an opening may be expressed as shielding effectiveness. Shielding effectiveness may be measured as the percentage decrease in radiation that passes through a panel opening with the component in place relative to when the component is absent.
Aspects of the present disclosure may be embodied as a spring seal for a cage of a connector assembly configured to receive a plug inserted in an insertion direction. The spring seal may comprise a conductive sheet comprising a plurality of peaks separated in the insertion direction.
Aspects of the present disclosure may be embodied as a connector assembly, comprising a receptacle connector within a cage comprising a channel with an opening and a plurality of spring seals disposed at the opening of the channel. Each of the plurality of seals may comprise a corrugated sheet comprising a plurality of peaks and a plurality of valleys, with conducting paths between each of the plurality of peaks and an adjacent valley of the plurality of valleys having a length of 1 mm or less.
Aspects of the present disclosure may be embodied as a method of operating an electronic assembly comprising a receptacle accessible within a channel of a cage having a spring seal at an opening to the channel. The method may comprise inserting a transceiver through the opening to the channel, contacting a first convex surface of the spring seal at a first distance from the opening, contacting a second convex surface of the spring seal at a second distance from the opening, and contacting a third convex surface of the spring seal at a third distance from the opening, such that the spring seal is compressed between the transceiver and a wall of the cage.
The foregoing is a non-limiting summary of the invention, which is defined by the appended claims.
The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:
The inventors have recognized and appreciated structures for enhancing the shielding effectiveness of an I/O connector assembly including a cage. Increased shielding effectiveness may be provided by a spring seal between a cage and a pluggable component with a plurality of segments, each of which can make contact with a wall of the cage in multiple locations spaced apart in an insertion direction of the transceiver into the cage.
The spring seal may have a plurality of peaks and valleys. The peaks may be orientated to contact the exterior housing of a transceiver or other pluggable component and the valleys may be oriented to contact the walls of a cage. Separation, in a direction perpendicular to the wall of the cage, between the peaks and valleys when the spring is in an uncompressed state, may be larger than the tolerance in positioning between the exterior of the transceiver housing and the cage wall, which will result in the spring seal being compressed in a direction toward the wall of the cage when the transceiver is inserted in the cage.
In the illustrated embodiment, an EMI seal 134 at the opening of each channel of the cage is formed by spring seals as described herein mounted to all four interior walls at the opening into each channel. In this exemplary embodiment, each spring seal is formed from a sheet of metal. The walls of the cage may be formed of stainless steel and the spring seal may be formed from a material that is less likely to yield when compressed. For example, the spring seal may be stamped from a sheet of phosphor bronze. The spring seal may include a plating, such as nickel plating.
The transceiver may have a conductive exterior 212 that is contacted at multiple locations along the insertion direction by the spring seals lining the walls of the channel at its opening. As can be seen in
As can be seen, such as in
A spring seal may alternatively or additionally include an attachment mechanism at the rear. In the embodiment of
In this example, slits 440 are cut in the shield. In this example, the slits 440 have elongated dimensions parallel to the insertion direction. In the example illustrated, the slits are cut in interior portions of the metal sheet forming the spring seal such that the slits have closed perimeters. The slits 440 are transverse to the elongated dimension of the peaks and valleys. Such an orientation leaves multiple segments 442 providing conducting paths between the slits and connecting the peaks and valleys.
The slits 442 may modify the stiffness of the shield. In the illustrated embodiment, there are more slits at the front and rear than in the central portion. The density of openings is therefore greater at the front and rear than in the central portion. In the illustrated example, the average spacing between slits at the front and rear is about half that in the central portion. The average spacing between slits in the front and rear portion may be, in some examples, between 30% and 70% of the average spacing in the central portion. Such a configuration provides for a stiffer spring force from the central portion of the shield with lesser spring force at the front and back.
The spring shield 550 as shown in
In the example of
As can be seen in
There will be conducting paths through the shields between each of these points of contact at the peak and the locations designated by X's on the wall of the cage. In this example, there are conducting paths between each peak and the wall of the cage extending in both directions from the peak. These paths are relatively short. For example, in this example the spring seal may be formed with a height H in an uncompressed state on the order of 1 mm, such as between 0.5 mm and 2 mm, or 0.5 mm and 1 mm or approximately 0.75+/−0.1 mm. The height, for example, may be less than 1 mm. The conducting paths may have a length on the order of 1.0 mm, such as less than 1 mm. These dimensions have been found to provide enhanced performance of a system using cages, transceivers and receptacle connectors made according to an OSFP standard.
A spring seals as described herein has been found to provide improved high frequency performance for an electronic system with an I/O connector. Without being bound by any particular theory, the inventors theorize that the multiple peaks and valleys result in short conducting paths through the seal across the gap between the transceiver and the cage. These conducting paths will be shorter than spring fingers as shown in
Designs as disclosed herein with multiple peaks and valleys facilitate shorter conductive segments bounding openings in a panel, contributing to enhanced performance, particularly in high frequency systems where resonances might otherwise degrade performance. For example, a seal as described herein may be useful such as at the high frequencies used with OSFP connectors.
As can be appreciated from the foregoing, a cage with a spring seal as described above may be used in a method of operating an electronic assembly comprising a receptacle accessible within a channel of a cage and having a spring seal at an opening to the channel. An exemplary method may comprise inserting a transceiver through the opening to the channel; contacting a first convex surface of the spring seal at a first distance from the opening; contacting a second convex surface of the spring seal at a second distance from the opening; and contacting a third convex surface of the spring seal at a third distance from the opening, such that the spring seal is compressed between the transceiver and a wall of the cage. The method may include mating the transceiver with a connector in the channel.
A spring seal used with this method may comprise a front portion adjacent the opening and a rear portion offset from the front portion in an insertion direction. The rear portion of the spring seal may move in the insertion direction when the spring seal is compressed.
Contacting the first convex surface may compress the spring seal to generate a first contact force between the first convex surface and the transceiver. Contacting the second convex surface may compress the spring seal to generate a second contact force between the second convex surface and the transceiver, and the second contact force may be greater than the first contact force.
Compressing the spring seal between the transceiver and a wall of the cage may forms a plurality of conducting paths between the transceiver and the wall of the cage that are less than 1 mm long.
Compressing the spring seal between the transceiver and the wall of the cage may form a plurality of ground connections between the transceiver and the wall of the cage. When the transceiver is operated at a high frequency, such as within an operating frequency range of an OSFP standard, the plurality of ground connections may suppress resonance in the operating frequency range in a space between the transceiver and the wall of the cage.
Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art.
For example, a spring seal as described herein may also be used between other components. A spring seal was described above as making electrical connections between a transceiver and a cage. In other embodiments, the spring seal may make multiple connections between a transceiver and another grounded structure of an electronic assembly with a receptacle I/O connector. In yet other embodiments, rather than a transceiver, the spring seal may be disposed between a passive plug or other pluggable component and a wall of the cage.
As another example, a cage with four walls bounding a channel opening is illustrated. In embodiments in which pluggable components that are not rectangular are inserted into the cage, there may be more or fewer interior walls of the cage, and therefore more or fewer spring seals around the perimeter of the opening into the cage.
As yet a further example, a spring seal is described in which the spring seal is fixed at the front and retained at the rear from movement in a direction perpendicular to the wall of the cage at the rear. The rear of the spring seal may be free to move in the insertion direction. Such a mounting enables the spring seal to elongate in the insertion direction when a transceiver is inserted into the cage. Such a configuration provides a softer spring force against the transceiver and provides less stress on the spring, reducing the chances of yield. In other embodiments, however, a higher spring force may be beneficial, and both the front and back of the spring may be secured to the cage so as to preclude movement in the insertion direction.
Moreover, it is not a requirement that there be a one-to-one relationship between interior walls of the cage and spring seals. In some embodiments, for example, there may be more than one spring seal per wall. Multiple spring seals, for example, may be aligned end to end to span the wall of the cage. Conversely, there may be some walls for which there is no spring seal. Such an embodiment may be useful in which an alternative type of shield is used for one or more walls and/or the transceiver is mounted asymmetrically in the channel of the cage. One wall of the transceiver, for example, may be pressed against a wall of the cage without an intervening spring seal. As a specific example, spring seals may line at least two walls of the cage.
For systems with greater variability in the positioning of the transceiver walls relative to the walls of the cage, the variability in the amount of compression required of the spring seal may also be greater. In such an embodiment, more slits may be formed than illustrated to provide a softer spring force for more compression without yielding.
As a further example of a possible variation, peaks and valleys are shown elongated in a direction perpendicular to the insertion direction. The peaks and valleys may be oriented at another angle transverse to the insertion direction or may be parallel to the insertion direction.
As yet another example of a possible variation, a spring seal was illustrated in use on a ganged cage with four channels, arranged side by side in a direction parallel to a surface of a printed circuit board to which the cage is attached. Spring seals as described herein may be used in connection with ganged cages with any number of side-by-side channels. Spring seals as described herein also may be used in connection with a stacked cage in which one or more channels are arranged above, in a direction parallel to a surface of a printed circuit board to which the cage is attached, another channel. A spring seal as described herein may also be used in a connector assembly with ganged, stacked cages or in connection with cages that are not ganged, whether single channel or stacked cages.
Such alterations, modifications, and improvements are intended to be part of this disclosure and are intended to be within the spirit and scope of the invention. Further, though advantages of the present invention are indicated, it should be appreciated that not every embodiment of the invention will include every described advantage. Some embodiments may not implement any features described as advantageous herein and in some instances. Accordingly, the foregoing description and drawings are by way of example only.
Various aspects of the present invention may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and is therefore not limited in its application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments.
Also, the invention may be embodied as a method, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.
Also, circuits and modules depicted and described may be reordered in any order, and signals may be provided to enable reordering accordingly.
Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.
All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.
The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”
As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified.
The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.
As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.
Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.
This application claims priority to and the benefit of U.S. Provisional Application Ser. No. 63/208,200, filed Jun. 8, 2021, entitled “I/O CONNECTOR CAGE WITH HIGH SHIELDING EFFECTIVENESS.” The entire contents of this application are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63208200 | Jun 2021 | US |
