Patent Abstract:
A computer system is provided, including: a computer chassis configured to retain a motherboard having a plurality of I/O (input/output) connectors mounted thereon; and an electrically conductive door movable from an open position to a closed position, wherein when said door is in the open position, the I/O connectors are exposed, and when said door is in the closed position, the I/O connectors are covered. A method of operating a computer including a motherboard having a plurality of I/O (input/output) connectors mounted thereon is provided. The method includes operating the computer to generate electromagnetic signals, and blocking the electromagnetic signals with an electrically conductive door movable from an open position to a closed position, wherein when said door is in the open position, the I/O connectors are exposed, and when said door is in the closed position, the I/O connectors are covered.

Full Description:
RELATED APPLICATION 
     The present application claims the benefit of U.S. Provisional Patent Application Nos. 60/569,020, filed on May 7, 2004 and entitled “ELECTROMAGNETIC INTERFERENCE SHIELD FOR I/O PORTS”; 60/568,969, filed May 7, 2004 and entitled “INTERFACE ASSEMBLY”; 60/569,025, filed May 7, 2004, entitled “RACK MOUNTED COMPUTER SYSTEM”; and 60/569,019, filed May 7, 2004 and entitled “DIRECTIONAL FAN ASSEMBLY”, all of which are hereby incorporated by reference as if fully set forth herein. 
    
    
     BACKGROUND 
     1. Field 
     This is related generally to electronic equipment, such as computer systems including a plurality of input/output connectors associated therewith. Certain aspects relate to methods and systems for selectively shielding or blocking electromagnetic signals from a computer system. 
     2. Description of Related Art 
     Electronic equipment, such as computers in a rack-based server system, radiate electromagnetic signals, which can cause electromagnetic interference (EMI) adversely affecting other electronic equipment positioned nearby. The amount of radiated EMI has increased with increasing operational frequencies and power of contemporary computers. Computer designers typically attempt to eliminate or reduce EMI by enclosing the computer in electromagnetic shielding. However, these computers generally contain a plurality of components that need to be periodically accessed by the computer operator, such as I/O ports, storage devices, removable media, and power supplies. Therefore, the housing providing the electromagnetic shielding should provide some access to those components. 
     Computers typically include a plurality of input/output (I/O) ports for coupling the computers with network cables or other external devices.  FIG. 1  shows a prior art group of I/O ports on a computer  100  (only the motherboard  112  and the front panel  114  are shown). These I/O ports typically comprise board-mounted portions mounted onto the computer motherboard  112  and terminating in I/O connectors  120  (e.g., sockets) which can be coupled with corresponding I/O connectors for each I/O device being connected to the computer (e.g., plugs that can be inserted into the I/O connector  120 ). I/O ports may be used, for example, for connecting the computer to peripherals, network cables, keyboards, monitors, and the like. 
     When a plurality of I/O connectors  120  are provided in an opening  122  along a single wall of the computer enclosure, the I/O connectors  120  are usually separated from the edges of the opening  122  and from each other by small gaps. These gaps may allow an unacceptable amount of electromagnetic signals to radiate from the computer. Therefore, a sheet metal I/O shield  110  having a plurality of I/O connector openings  102  is typically used to receive the I/O connectors  120  and to provide EMI shielding for the gaps between the I/O connectors  120 . These I/O shields  110  are sometimes referred to as EMI/RFI connector gaskets. However, because a single metal sheet is used to shield multiple I/O connectors, any redesign of the I/O connector layout would require that a new I/O shield be designed and fabricated. This can undesirably increase manufacturing costs, in addition to adding delays to the design timeline for new products. In addition, if a manufacturer has multiple computer models, multiple I/O shield designs must be kept in stock in order to be available for new orders. 
     Accordingly, it may be desirable to provide a system for blocking or reducing undesirable EMI emissions, while maintaining flexibility in I/O connector layout. 
     SUMMARY OF THE INVENTION 
     According to one aspect, a computer system is provided. In one example, the computer system includes a computer chassis configured to retain a motherboard having a plurality of I/O (input/output) connectors mounted thereon; and an electrically conductive door (e.g., a shield) movable from an open position to a closed position, wherein when said door is in the open position, the I/O connectors are exposed, and when said door is in the closed position, the I/O connectors are covered. 
     According to another aspect, methods of operating a computer system comprising a motherboard having a plurality of I/O (input/output) connectors mounted thereon is provided. In one example, the method includes operating the computer to generate electromagnetic signals; and blocking at least a portion of the electromagnetic signals with an electrically conductive door movable from an open position to a closed position, wherein when said door is in the open position, the I/O connectors are exposed, and when said door is in the closed position, the I/O connectors are covered. 
     Other features and aspects of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the features in accordance with embodiments of the invention. The summary is not intended to limit the scope of the invention, which is defined solely by the claims attached hereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of a computer system having a prior art I/O shield. 
         FIGS. 2A-2B  show perspective views of a computer with the top cover removed, in accordance with embodiments of the present invention. 
         FIG. 3  shows another perspective view of a computer in accordance with embodiments of the present invention. 
         FIG. 4  shows a perspective view of the back side of an I/O door in the closed position, in accordance with embodiments of the present invention. 
         FIG. 5  shows a front view of the I/O door in the open position, in accordance with embodiments of the present invention. 
         FIG. 6  shows another embodiment of an I/O door, in accordance with embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, reference is made to the accompanying drawings which illustrate several embodiments of the present invention. It is understood that other embodiments may be utilized and mechanical, compositional, structural, electrical, and operational changes may be made without departing from the spirit and scope of the present disclosure. The following detailed description is not to be taken in a limiting sense, and the scope of the embodiments of the present invention is defined only by the claims of the issued patent. 
       FIGS. 2A and 2B  show perspective views of a computer  200  with the top cover  210  removed, in accordance with embodiments of the present invention. The computer  200  may comprise a computer chassis  202  containing a motherboard  204  and other components, such as one or more power supplies  206 , hard drives  208   a - 208   b , processors  224 , and expansion cards. An exemplary computer  200  is described in greater detail in the following U.S. patent applications, all filed on May 7 th , 2004, the disclosures of which are incorporated by reference herein in their entireties: provisional patent application No. 60/568,969, entitled “INTERFACE ASSEMBLY”; provisional patent application No. 60/569,025, entitled “RACK MOUNTED COMPUTER SYSTEM”, and provisional patent application No. 60/569,019, entitled “DIRECTIONAL FAN ASSEMBLY”. 
     A computer may include any electronic system designed to perform computations and/or data processing. In some embodiments, the computer includes an electronic device having a central processing unit (CPU) and memory. The CPU and memory may be provided on a main board, which, in turn, may be mounted to a computer chassis. This chassis may comprise, for example, a housing that encloses all or portions of the main board and components coupled thereto. Alternatively, the computer may comprise a printed circuit board (PCB) main board having exposed components without an enclosure. The chassis may comprise a minimal structure (such as, e.g., a tray or frame) which provides mechanical support for the main board when the main board is being handled or mounted in a rack. 
     Computer  200  may be configured to be mounted in a computer rack assembly with the front side  212  of the computer  200  facing outward such that it is accessible to the computer operator. The front side  212  may include various features that the operator may wish to access during use. These features may include, for example, an on/off switch, a floppy drive, and an I/O door  220  covering an I/O port access aperture  222 . 
     The I/O door  220  is shown in the closed position in  FIG. 2A  and in the open position in  FIG. 2B . When the I/O door  220  is in the open position, a plurality of I/O ports are exposed and accessible to the operator through the I/O port access aperture  222 . The types of I/O ports may vary depending on the motherboard configuration, but may include, for example, one or more network connectors  310   a - 310   b  (shown in this embodiment as female RJ45 connectors), a video port  312 , a SCSI port  314 , a USB port  316 . The I/O ports may further include, for example, parallel ports, SCSI ports, mouse and/or keyboard ports, such as AT or PS/2 connectors. 
       FIG. 3  shows a perspective view of the computer  200  with the top cover  210  in place and the I/O door  220  in the closed position.  FIG. 4  shows a perspective view of the back side of the computer  200 , showing the back side of the I/O door  220 .  FIG. 5  shows a front view of the computer  200 , showing the I/O door  220  in the open position exposing the I/O ports of the computer  200 . 
     It can be seen that there are gaps between the various I/O ports exposed by the I/O port access aperture  222 . In a conventional arrangement, an I/O shield would be fabricated based on the layout of these I/O ports and would be fitted into a hole on one of the walls of the computer chassis. This I/O shield would block the electromagnetic signals from emanating out of the computer  200 . Without the I/O shield, the electromagnetic signals may pass through the gaps between and around the various I/O ports and radiate from the opening defined by the I/O port access aperture  222 . However, in the illustrated embodiment, the I/O shield can be omitted and the I/O door  220  can be used instead to inhibit the radiation of the electromagnetic signals. 
     In the illustrated embodiment, I/O door  220  comprises an electrically conductive material, such as stainless steel, which provides shielding to inhibit the emissions of electromagnetic signals when computer  200  is in operation. The I/O door  220  may comprise, for example, a solid plate, or may contain small slits or apertures which provide a desired level of EMI shielding, yet allow air to pass through the I/O door  220  into and/or out of the interior of the computer  200 , for example, to cool components of computer  200 . In some embodiments, I/O door  220  may be formed at least partially out of an electrically non-conductive material, such as, e.g., plastic, in order to decrease manufacturing costs and improve aesthetic appearance. A conductive insert, such as, e.g., a wire mesh screen or a perforated metal plate, may be added to a plastic body in order to provide the desired levels of EMI shielding. 
     The I/O door  220  may be configured to be movable from a closed position, as shown in  FIG. 2A , to an open position, as shown in  FIG. 2B . In the illustrated embodiments, the I/O door  220  is mounted on a hinge, thereby enabling the I/O door  220  to rotate about an axis between the open and closed position. A flange  230  may be provided on the I/O door  220  to facilitate easy opening by a user. In other examples, the I/O door may slide between the open and closed positions. In yet other examples, the I/O door may be removable to expose the I/O ports. Other I/O door configurations may be used, as would be understood by one of ordinary skill in the art. 
     When the I/O door  220  is in the closed position, the I/O port access aperture  222  is sufficiently shielded to reduce electromagnetic emissions to an acceptable level. Accordingly, no separate I/O shield is needed to block the electromagnetic signals radiating through the gaps between the I/O ports (e.g., network ports  310   a - 310   b  and serial port  312 ). When an operator wishes to access the I/O ports, I/O door  220  can be opened to expose the I/O port access aperture  222 . Depending on the application, the operator may only need to access the I/O ports on an infrequent basis, so the EMI caused by the opening of the I/O door may be negligible. 
     In some embodiments, it may be desired to run a cable into the front of the computer  200  for connection with one of the I/O ports, such as, e.g., network port  310   a . In this situation, the I/O door  220  may be left in a partially open position to provide sufficient clearance for the network cable to pass through the I/O port access aperture  222 , while still blocking the desired amount of the electromagnetic signals emitted by the computer  200 . It may be desirable to provide spring-loaded hinges for the I/O door  220  in order to provide a constant bias to move the I/O door  220  into the closed position, thereby minimizing the extent that the I/O door  220  is opened to accommodate the network cable. 
       FIG. 6  shows another embodiment of an I/O door  600  defining a cable passage aperture  602  covered by an aperture cover  604 . With this embodiment, I/O door  600  can be opened by the operator to access the I/O ports in order to couple an I/O connector (e.g., a network cable) with one of the I/O ports (e.g., network port  310   a ). After the network cable has been plugged into the network port  310   a , the aperture cover  604  can be opened and the network cable can be passed through the cable passage aperture  602  to emerge from the front of the computer. This way, the primary I/O door  600  can be completely shut, leaving only a small aperture  602  through which one or more cables may pass. This arrangement can minimize the amount of electromagnetic signal leakage that may result when a cable is connected to one of the I/O ports and passed out of the front of the computer. The aperture cover  604  may be spring-loaded to provide a constant bias to keep cover  604  closed. 
       FIG. 6  also shows a compressible grounding member  610 , which may be provided in accordance with some embodiments of the present invention. This grounding member  610  may comprise, for example, a mass of steel wool or a compressible foam block having a conductive metallic surface. The computer may be configured such that the ends of the I/O ports are set back from the front side of the computer. Thus, when the I/O door  220  described above is closed, there is a small gap between the fronts of the I/O ports and the back of the I/O door  200 . 
     When the I/O door  600  shown in  FIG. 6  is in the closed position, the grounding member  610  spans the gap between the I/O door  600  and the fronts of the I/O ports such that the conductive surface of the grounding member  610  contacts the fronts of the various I/O ports to provide an electrical connection between the I/O ports and the I/O door  600 . The I/O door  600 , in turn, may be electrically coupled to the computer chassis. This arrangement can be used to ground the I/O ports and discharge any undesirable buildup of electrical charge in the I/O ports. This can prevent damage to the components of the computer caused by static electricity. The grounding member  610  may be formed of a compressible or compliant material in order to accommodate variations in the positions of the I/O ports and to allow the I/O door  600  to be fully closed, even when a cable is coupled with one or more of the I/O ports. It may also be desirable for the grounding member  610  to be porous or to contain large apertures in order to allow cooling air to flow through the apertures  612  in the I/O door  600  into and/or out of the computer. 
       FIG. 6  also shows in greater detail an I/O door grounding flange  232  that may be used in accordance with various embodiments in order to improve the grounding of the I/O door. The I/O door may be grounded at the point where the door is hinged with the computer chassis  202 , but the grounding flange  232  may provide additional grounding as well. In addition, the grounding flange  232  may provide shielding of electromagnetic signals around the edge of the I/O door. The flange  232  may be mounted directly onto the computer chassis  202  such that the flexible fingers  234  of the flange  232  contact the bottom edge of the I/O door  600  when the door is closed to provide improved grounding, while flexing in order to provide clearance for the door when moved to the open position. 
     With reference to  FIGS. 2A-5 , in accordance with some embodiments, a grounding shield  250  may be used to ground the various I/O connectors  102 . The grounding shield  250  may be positioned such that shield  250  maintains electrical contact with one or more of the I/O connectors  102  covered by the I/O door  220  such that the I/O connectors  102  are grounded. The grounding shield  250  may be mounted to the computer chassis  202  and positioned to be in electrical contact with one or more of the I/O connectors  102  covered by the I/O door  220 . As can be seen in  FIG. 5 , the grounding shield  250  may have a size much smaller than the size of the I/O port access aperture  222 . Thus, cooling air is able to move freely through the I/O port access aperture  222  into and/or out of the computer chassis  202 . This is in contrast with conventional I/O shields, which block the flow of air into the computer. In addition, the small size and simplicity of the grounding shield  250  facilitates simple manufacturing and installation. 
     In accordance with embodiments of the present invention, an I/O door may be used to block the emission of undesirable electromagnetic signals while enabling an operator to access the I/O ports of the computer. The I/O door can eliminate the need for I/O shields and can be used with any arrangement of I/O ports. Therefore, it may be no longer necessary to design and manufacture a customized I/O shield each time a new I/O port layout is produced. This can decrease the lead time needed to release new computers incorporating new motherboard designs and can further enable a single computer chassis design to be used with a plurality of motherboards without the need to maintain an inventory of I/O shields customized for each motherboard layout. 
     While the invention has been described in terms of particular embodiments and illustrative figures, those of ordinary skill in the art will recognize that the invention is not limited to the embodiments or figures described. For example, the embodiments described herein show a computer having an I/O door covering I/O ports provided on the front side of the computer. In other embodiments, the I/O ports and I/O door may be provided on other locations of the computer, such as the back side. In addition, the I/O connectors shown and described herein are mounted directly onto the surface of the motherboard of the computer. In other embodiments, the I/O connectors in the computer may be mounted on separate components, such as daughterboards or expansion cards. 
     In addition, in some embodiments, all of the I/O ports for the computer are provided at a single location accessible through the I/O port access aperture and covered by the movable I/O door. In other embodiments, additional I/O ports may be provided elsewhere on the computer which are not covered by the I/O door. For example, in the some embodiments, all of the network connectors are covered by the I/O door, and in other embodiments, some of the network connectors may be provided elsewhere. In yet other embodiments, an I/O shield may be used with a set of frequently used I/O ports, and an I/O door may be used with infrequently used ports. 
     It is also understood that I/O doors in accordance with embodiments of the present invention may not completely block all of the electromagnetic signals being generated within the computer  200 . Depending on the intended installation site of the computer  200 , different levels of electromagnetic emissions may be acceptable. For example, a manufacturer may design the I/O door to provide a sufficient level of shielding to pass one or more industry standards. The precise design and configuration of the I/O door may vary, depending on the computer and the desired level of acceptable EMI. In addition, although the I/O door may provide a sufficient level of EMI shielding without the need for an I/O shield, an I/O shield may be used in conjunction with an I/O door, in accordance with embodiments of the present invention. This may be desirable when the I/O shield covers some of the gaps between the I/O ports, but does not alone provide the desired level of shielding. An I/O door may be used to supplement the I/O shield&#39;s shielding capacity. 
     It will also be understood that I/O doors in accordance with other embodiments need not have the same or similar dimensions and position as the illustrated I/O door  220 . For example, the I/O door may comprise a larger or smaller portion of the front side of the computer. In yet other embodiments, the I/O door may comprise substantially the entire front side of the computer chassis. 
     The figures provided are merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized.  FIGS. 1-6  are intended to illustrate various implementations of the invention that can be understood and appropriately carried out by those of ordinary skill in the art. 
     Therefore, it should be understood that the invention can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be understood that the invention can be practiced with modification and alteration and that the invention be limited only by the claims and the equivalents thereof.

Technology Classification (CPC): 7