Abstract:
A shield member for installation on a computer housing includes a generally planar plastic body. The plastic body has at least one opening formed therein to accommodate insertion through the body of at least one computer input/output cable. The shield member also includes a plurality of attachment members integrally formed with the plastic body to attach the shield member to the computer housing. In addition, the shield member includes an electrically-conductive film molded into the plastic body.

Description:
BACKGROUND 
   In the case of many personal computers, electronic components are contained within a housing. The rear wall of the housing is typically constituted by a thin metal shield, sometimes referred to as an “I/O shield”. This term may be considered short-hand for an input/output access shield. The I/O shield typically has openings formed therein to allow input/output cables to be inserted through the I/O shield to allow the cables to be interfaced to the electronic components within the housing. Because the shield is metal it may function to inhibit electromagnetic interference (EMI) signals from passing through the shield. 
   The cost of manufacturing conventional I/O shields may be higher than is desirable. Furthermore, it may be inconvenient to mount conventional I/O shields to the balance of the housing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an elevational view of an I/O shield member according to some embodiments. 
       FIG. 2  is a top view of the I/O shield member of  FIG. 1   
       FIG. 3  is an end-on view of the I/O shield member of  FIGS. 1 and 2 . 
       FIG. 4  is a schematic cross-sectional view of the I/O shield member of  FIGS. 1–3   
       FIG. 5  is a flow diagram that illustrates a process for manufacturing the I/O shield member of  FIGS. 1–4  according to some embodiments. 
       FIG. 6  is a schematic side view of a computer system that includes the I/O shield member of  FIGS. 1–4 . 
   

   DETAILED DESCRIPTION 
     FIG. 1  is an elevational view of an I/O shield member  10  as provided in accordance with some embodiments. For convenience of presentation, the shield member  10  is shown in  FIG. 1  with its longest dimension oriented horizontally. However, in at least some cases, the longest dimension of the shield member  10  may be oriented vertically, so that the shield member  10  may be suitable for closing the rear of a conventional personal computer “tower” housing.  FIGS. 2 and 3  are other views of the shield member  10 , with  FIG. 2  being a top view and  FIG. 3  being a view of an end of the shield member  10 . 
   As seen from  FIGS. 1–3 , the shield member  10  is in the general form of a planar body with a rectangular profile. The shield member  10  has a number of openings formed therethrough, including openings  12 ,  14  and  16  (seen in  FIG. 1 ) for accommodating computer input/output cables (not shown) to be inserted through the openings and thus through the shield member  10  to allow the cables to be interfaced to internal electronic components (not shown) housed within a computer housing (not shown in  FIGS. 1–3 ) to which the shield member  10  may be installed. For example, openings  12 ,  14 ,  16  may accommodate plugs from devices such as printers or scanners. The openings formed through the shield member  10  further include openings  18 ,  20 ,  22 ,  24 ,  26 ,  28 ,  30 ,  32 ,  34 ,  36 ,  38  and  40  for accommodating connections to devices such as mice, keypads and USB ports. In other embodiments, the numbers, shapes and/or locations of the openings may be different from those shown in  FIG. 1 . 
   The shield member  10  further includes a flange  42  (best seen in  FIGS. 2 and 3 ) which runs around the periphery of the shield member  10  and which extends normal to the plane of the shield member in a direction that is inward relative to a computer housing (not shown in  FIGS. 1–3 ) to which the shield member  10  may be installed. The extent of the flange  42  in the inward direction may be on the order of 1 to 2 mm, in some embodiments. The flange  42 , and indeed all other features of the shield member  10  illustrated in  FIGS. 1–3 , may be integrally formed with shield member  10 . 
   The shield member  10  may also include snap members  44  formed at respective points along the flange  44 . The snap members  44  are six in number in the embodiment shown, though there may be more or fewer in other embodiments, and the locations thereof may be changed. The snap members  44  extend normal to the plane of the shield member  10  in the above-mentioned inward direction relative to the computer housing (not shown in  FIGS. 1–3 ) to which the shield member  10  may be installed. The snap members  44  may operate as attachment members by which the shield member  10  may be attached and/or secured to the computer housing. In other embodiments, some or all of the snap members may be dispensed with in favor of small spherical domes (not shown) which may be formed on the flange  42  extending radially outwardly from the flange  42  to allow the shield member  10  to be attached/secured to the computer housing via the spherical domes. 
   The shield member  10  may also include contact members  46  located at various locations across the planar extent of the shield member  10 . The contact members  46  may be rounded and may extend in the above-mentioned inward direction normal to the plane of the shield member  10 . In some cases the contact members  46  may be associated with some of the openings (e.g., openings  12 ,  14 ,  16 ) formed in the shield member  10 . A purpose of the contact members  46  is to be in electrically conductive contact with one or more circuit boards (not shown in  FIGS. 1–3 ) installed within the computer housing (not shown in  FIGS. 1–3 ) to which the shield member  10  may be installed. For that purpose, as will be explained below, at least the inward-facing surfaces (inward direction indicated by arrows  48 ,  50  in  FIGS. 2 and 3  respectively) of the contact members  46  may be electrically conductive. 
   As indicated by the above description of the shield member  10  and the accompanying drawings, the shield member  10  may be configured to be attached to a computer housing ( FIG. 6 ) from outside the computer housing. 
   The composition of the shield member  10  will now be discussed.  FIG. 4  is a schematic partial cross-sectional view taken normal to the plane of the shield member  10  at a location (e.g., location  52 ,  FIG. 1 ) that is without features. According to some embodiments, the shield member  10  is formed as a molded plastic body into which an electrically-conductive film  54  ( FIG. 4 ) has been molded. It will be noted that the electrically-conductive film  54  is at an inner surface  56  (relative to the above-mentioned computer housing) of the plastic body which makes up the shield member  10 . Thus the inner surface  56  of the shield member  10  may be considered to correspond to the electrically-conductive film  54 . The extent of the electrically-conductive film  54  in the plane of the shield member  10  may be substantially the same as (i.e., may substantially match) the planar extent of the shield member  10 . Thus the surface area of the electrically conductive film  54  may be substantially the same as, and thus may substantially match, the surface area of the inner surface  56  of the shield member  10 . The electrically conductive film  54  may be suitable for blocking electromagnetic interference from entering or leaving a computer housing (not shown in  FIG. 4 ) of which the shield member  10  may be a part. Hence, the electrically conductive film  54  may be referred to as an “EMI film”. 
   The shield member  10  may be molded out of conventional plastic resin. The electrically conductive film  54  may be, for example, a metallized Lexan (polycarbonate) sheet available from General Electric plastics division. It will be noted that  FIG. 4  is not necessarily drawn to scale, and that the electrically-conductive sheet may be much thinner than is suggested by the drawing. In some embodiments, the typical over-all thickness of the shield member  10  (e.g., at a featureless location such as location  52 ,  FIG. 1 ) may be on the order of about 0.5 to 1.0 mm. 
     FIG. 5  is a block diagram that illustrates a process that may be performed in the course of manufacturing the shield member  10 . At  80  in  FIG. 5 , the electrically-conductive film (previously indicated as  54  in  FIG. 4 ) is placed in a suitable mold (not shown). Then, at  82  in  FIG. 5 , a plastic resin or the like is molded in the mold with the electrically-conductive film to form the plastic body  84  partially indicated in  FIG. 4 , so that the electrically conductive film  54  is molded into the plastic body  84 . The mold may be suitably sized and shaped to form the shield member  10  described above. In some embodiments, the molding performed at  82  may be injection molding. 
     FIG. 6  is a schematic side view of a computer system  100  provided in accordance with some embodiments. (To simplify the drawing, many components of the computer system are omitted.) The computer system  100  may include a housing  102  and a circuit board  104  mounted in the housing  102 . The circuit board  104  may include at least one integrated circuit, such as microprocessor  106  mounted on the circuit board  104 . The circuit board may also include a chipset  108  in communication with the microprocessor  106 . 
   The computer system  100  may further include an I/O shield member  10  like that described above. The shield member  10  may be installed on the housing  102  and may form the rear wall thereof. The shield member  10  may be in electrically-conductive contact with the circuit board  104  via, e.g., its contact members  46  ( FIGS. 2 and 3 ) and its electrically conductive film  54  which forms a surface of the contact members  46 . Other components that may, but need not, be included in the computer system  100 , and which are not shown, include (a) I/O cables inserted through the shield member  10  to be in electrically conductive contact with the circuit board  104  and/or other internal components of the computer system  100 ; and/or (b) peripheral components of the computer system  100  coupled to the circuit board  104  via the I/O cables. 
   The shield member as described hereinabove, made largely of plastic with an electrically-conductive film molded therein, may be manufactured more economically than a conventional metal I/O shield. Moreover, the shield member may be configured so as to be installable on the computer housing from the outside of the housing rather than from the inside, the latter being the case with respect to at least some conventional I/O shields. This feature of the shield member described herein may make assembly of the computer more convenient. Furthermore, the shield member as described herein may be more resistant to vibration than a conventional metal I/O shield and thus may be more reliably retained in place on the computer housing. Because of the presence of the electrically-conductive film in the shield member described herein, the shield member may be substantially as effective as a metal I/O shield in preventing transmission of electromagnetic interference to/from the interior of the computer housing. 
   The several embodiments described herein are solely for the purpose of illustration. The various features described herein need not all be used together, and any one or more of those features may be incorporated in a single embodiment. Therefore, persons skilled in the art will recognize from this description that other embodiments may be practiced with various modifications and alterations.