Abstract:
In some examples, an apparatus includes a housing comprising an inner surface provided with thermal members, and a thermal attachment to transfer heat generated by a heat producing component to the housing. The thermal attachment is thermally contacted with the inner surface of the housing, and the thermal members are arranged to steer heat from the heat producing component and transferred to the housing by the thermal attachment at a greater heat flow rate through the housing to a first region of the housing and at a lesser heat flow rate through the housing to a second region of the housing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation of U.S. application SER. No. 14/041,526, filed Sep. 30, 2013, which is a continuation of U.S. application Ser. No. 12/996,764, filed Dec. 7, 2010, now U.S. Pat. No. 8,564,943, which is a national stage application under 35 U.S.C. §371 of PCT/US2008/068519, filed Jun. 27, 2008, which are hereby incorporated by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    Conventional clamshell computer systems place a video controller and central processing unit (CPU) nearby in the base. The display refresh signals connect to a display housing. Heat generated by the video controller is dissipated in the base of the clamshell computer, with the heat dissipated in the display housing. The base of the clamshell computer is typically designed and constructed to connect and dissipate the heat from the combination of CPU and video controller. 
         [0003]    Liquid cooling systems have sought to take advantage of the large passive area of the display rear enclosure to dissipate heat. Those systems transfer heat from the base through the hinge cavity (using thermally conductive material, including water) and then radiate the heat passively across the surface of the display housing. However, the space that is used for the video graphics adapter (VGA) controller circuitry and its thermal evacuation may be substantial, increasing the size of the base of the clamshell computer. Typically, a small or thin base size is attractive to a user. In addition, thermal evacuation on the base places the heat on the lap of a user and the fans used to remove the heat make noise which may be unattractive. 
       SUMMARY 
       [0004]    Embodiments of various electrical housings, particularly display housings, are provided. In this regard, a representative housing, among others, includes one or more electrical components that are disposed at the housing; a thermal attachment that is designed to transfer heat generated by the one or more electrical components; and a rear enclosure that is designed to engage the thermal attachment. The rear enclosure is further designed to receive and dissipate the received heat from the thermal attachment. 
         [0005]    Other systems, methods, features, and advantages of the present invention will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0007]      FIG. 1  is a perspective view of an embodiment of a clamshell computer. 
           [0008]      FIG. 2  is a schematic view of a clamshell computer, such as that shown in  FIG. 1 . 
           [0009]      FIG. 3  is a preassembled view of a top housing of a clamshell computer, such as that shown in  FIG. 1 , having a thermal attachment. 
           [0010]      FIG. 4  illustrates a hot spot on a top housing of a clamshell computer, such as that shown in  FIG. 1 . 
           [0011]      FIG. 5  illustrates an ideal heat distribution across a rear enclosure of a clamshell computer, such as that shown in  FIG. 4 . 
           [0012]      FIG. 6  is a perspective view of an embodiment of a thermal attachment, such as that shown in  FIG. 3 . 
           [0013]      FIG. 7  is a perspective view of another embodiment of a thermal attachment and a rear enclosure, such as that shown in  FIG. 3 , that include isolating members that thermally isolate the thermal attachment from the rear enclosure. 
           [0014]      FIG. 8  includes a preassembled view and a cross-sectional view of another embodiment of a thermal attachment and rear enclosure, such as that shown in  FIG. 3 , that decrease thermal resistance to the rear enclosure. 
           [0015]      FIG. 9  includes an assembled view and a cross-sectional view of another embodiment of the thermal attachment and rear enclosure, such as that shown in  FIG. 8 . 
           [0016]      FIG. 10  is a schematic view of another embodiment of a clamshell computer, such as that shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Exemplary systems are first discussed with reference to the figures. Although these systems are described in detail, they are provided for purposes of illustration only and various modifications are feasible. 
         [0018]      FIG. 1  is a perspective view of an embodiment of a clamshell computer  100 . The clamshell computer  100  generally has two (2) pieces, e.g., a top housing  105  and a base  110 , joined by a hinge  115 . The top housing  105  includes a display device  120 , and the base  110  includes a central processing unit (CPU), battery, hard drive, etc. (not shown). Cables (not shown) communicate display data and power from the base  110  to the top housing  105 . The video graphics adapter (VGA) controller  125  is generally located in the top housing  105 . 
         [0019]    It should be noted that a clamshell computer is generally different from an “all in one” computer, where electrical functions are located together in the top housing. Typical examples of an “all in one” are the Sony W101, the Apple iMac, and tablet computers (also known as “slate”). In this disclosure, the clamshell computer has some software computation performed at the base  110 . It is possible that the method and system of dissipating heat described in this disclosure can be utilized in the “all in one” computer. 
         [0020]      FIG. 2  is a schematic view of the clamshell computer  100 , such as that shown in  FIG. 1 . The top housing  105  includes a liquid crystal display (LCD)  205  that is electrically coupled to the VGA controller  125  via, for example, a low-voltage differential signaling (LVDS) link or a DisplayPort  210 . The display  205  generally has no memory; the display link or port  210  can be a unidirectional bus carrying data to the LCD  205 . The VGA controller  125  is generally electrically coupled to a CPU  215  and main memory  225  via, for example, a peripheral component interconnect express (PCI-E) bus  220 . The VGA controller  125  is an engine that creates a visual page from a CPU instruction. 
         [0021]    A memory or a frame buffer (not shown) is located near the VGA controller  125 . The frame buffer holds the constructed image. The process of writing to the display  205  involves the VGA controller  125  repeatedly accessing the frame buffer data, pixel by pixel, then line by line, and transferring to the display  205 . The speed of the data across the link or port  210  is a function of the color depth of the display  205 , the display resolution, and the refresh rate of the image. 
         [0022]    With electrical components in the top housing  105 , heat can be created in the top housing  105  directly and dissipated there from the base  115 . The heat can spread to the top surface of the top housing  105  so as to avoid a “hot spot” on the rear of the top housing  105  that would be uncomfortable to a touch of the user. 
         [0023]      FIG. 3  is a preassembled view of a top housing of a clamshell computer, such as that shown in  FIG. 1 , having a thermal attachment. The top housing  105  includes the VGA controller  125  that is disposed between the LCD  205  and a thermal attachment  310 . The VGA controller  125  is placed on a separate printed circuit board (PCB) and is mounted on a top surface of a rear enclosure  305  via PCB fasteners  320 . The thermal attachment  310  includes holes  315  that register with the PCB fasteners  320 . Alternatively or additionally, the VGA controller  125  may be located along with the LCD display  205  itself. The thermal attachment  310  is disposed between the VGA controller  125  and the rear enclosure  305 , so heat is transferred from the VGA controller to the rear enclosure  305 , where heat meets cooler ambient air. The thermal attachment  310  covers a portion of the inner surface area of the rear enclosure  305 . The thermal attachment  310  is further described in relation to  FIGS. 5-7 . 
         [0024]      FIG. 4  illustrates a hot spot on a top housing of a clamshell computer  100 , such as that shown in  FIG. 1 . Attaching a heat source, e.g., VGA controller  125 , to a single point has potential limitations. The thermal resistance of many materials is linearly proportional to its thickness. The top housing  105  is generally thin (approximately one (1) or two (2) millimeters thick) and wide such that the thermal resistance in the X and Y direction is relatively higher than in the Z direction. Accordingly, attachment of a heat source to the rear enclosure  305  can create a localized hot spot  425  on the opposite side of the rear enclosure  305 . The amount of power dissipated can be limited by the maximum temperature allowed on the user-touchable surface of the rear enclosure  305 . This can limit the graphics performance of the clamshell computer  100 , since graphics performance of the clamshell computer  100  is proportional to the amount of power that the clamshell computer  100  consumes. 
         [0025]    Heat convection generally favors heat traveling upward towards a top edge  405  of the top housing  105 , making the bottom edge  410  of the top housing  105  cooler. Also, the conduction of heat via the hinges  115  ensures that the bottom edge  410  of the rear enclosure  305  is cooler than the top edge  405 . Since thermal resistance is linear to dimension, the corners  415  of the clamshell computer  100  are generally cooler than the middle edges  420  of the rear enclosure  305 . The combination of these forces generally means that a “hot spot”  425  is created. Eliminating the hot spot  425  (and dissipating the heat more evenly over the broadest possible surface area) is a challenge that is addressed in this disclosure.  FIG. 5  illustrates an ideal distribution across the rear enclosure  305 , in which heat is distributed evenly across the whole surface of the rear enclosure  305 . 
         [0026]      FIG. 6  is a perspective view of an embodiment of a thermal attachment  610 , such as that shown in  FIG. 3 . The thermal attachment  610  can be made of graphite material that is capable of distributing temperature; whereas, most material (plastic, air, metal) is generally thermally conductive no matter the orientation. In addition, graphite can be formed into sheets that are highly conductive in a plane and moderately conductive in other directions. For example, a graphite sheet may be highly conductive (1000W/mK) in the flat X-Y direction, but moderately conductive (50W/mK) in the thin Z direction. So, graphite can be used to “steer” heat, especially for the purpose of decreasing touch temperature and dissipating the hot spot  425  ( FIG. 4 ) by spreading the heat uniformly among a broad surface, generally before conducting to the surface of the rear enclosure  305 . 
         [0027]    However, using a graphite sheet has some disadvantages. For example, the graphite sheet is not of uniform temperature. Though the graphite is highly thermally conductive, the longer distances, especially the corners, are generally cooler. Also, thermal conductivity depends on the thickness of the material, and it may be attractive to maintain a thin display enclosure. In addition, the contact point where the VGA controller  125  attaches to the graphite sheet can be the hottest location. Further, conduction in the Z plane may be lower than optimal, to transfer heat to the enclosure rear surface. 
         [0028]    Thermal conductivity of the graphite sheet can be controlled by a pattern of perforations  625 . In this example, heat is steered toward the corners by introducing perforation patterns  625  in the area of the highest heat flow. The perforations patterns  625  are designed and arranged in a triangular shape, where the bases  630  of the perforated triangles  625  are adjacent to the side edges of the thermal attachment  610  and the top corners  635  of the perforated triangles  625  are pointing toward the center of the thermal attachment  610 . Alternatively or additionally, the perforated patterns can have other geometric shapes, such as, diamond, square, heptagon, and other polygonal shapes. 
         [0029]    The perforations  625  at the top corners  635  of the perforated triangles are larger than the perforations  625  at the bases  630 . The size of the perforations gradually increases from the base  630  to the top corner  635 . The perforations  635  can cause interruptions of the thermal conduction. In this case, a heat source located in the middle of the top housing  105  can promote heat flow to the cooler corners of the top housing  105 . 
         [0030]    The contact area of the VGA controller  125  to the thermal attachment  610  can be the highest temperature point. The rest of the rear enclosure  305  can be highly conductive if the rear enclosure  305  is made of magnesium or aluminum and not plastic. The enclosure area opposite the contact area is isolated from the hot spot  425  by any of the following methods, among others:
       a. the center of the rear enclosure  305  is recessed or dished  620  (so as not to make contact with the graphite sheet).   b. an insulative material (not shown), e.g. a poor thermal conductor such as rubber foam, is positioned between the thermal attachment  610  and the rear enclosure  305 .   c. a decoration (not shown) made of relatively poorly conducting material is placed on the outside of the rear enclosure  305 . The decoration can include the clamshell computer logo.       
 
         [0034]      FIG. 7  is a perspective view of another embodiment of a thermal attachment  710  and a rear enclosure  705 , such as that shown in  FIG. 3 , that include isolating members that thermally isolate the thermal attachment  710  from the rear enclosure  705 . The isolating members  715 ,  720  facilitate controlling contacts between the thermal attachment  710  and the rear enclosure  705 . The isolating member  715 ,  720  can be recesses  715 ,  720  which thermally isolate the thermal attachment  710 . The recesses  715 ,  720  could be formed on the inner surface  725  of the rear enclosure  705 . 
         [0035]    A patterned conductive sheet (not shown) could be applied in between the thermal attachment  710  and rear enclosure  705 . Lastly, thermally conductive adhesive could be applied to control the conduction of heat from the thermal attachment  710  to the rear enclosure  705 . In this example, the isolating member  715  includes multiple parallel recesses in a diamond shape and the isolating member  720  includes multiple parallel recesses in a triangular shape, both having a corner pointing towards the side edge of the rear enclosure  705 . However, the isolating member  715  can have other geometric shapes, such as, square, heptagon, and other polygonal shapes 
         [0036]      FIG. 8  includes a preassembled view and a cross-sectional view of another embodiment of a thermal attachment  810  and rear enclosure  805 , such as that shown in  FIG. 3 , that decrease thermal resistance to the rear enclosure  805 . The rear enclosure  805  has a pattern of thermal ridges  820  disposed on the inner surface  825  of the rear enclosure  805 . The thermal attachment  810  has a complementary pattern of slots  815  that registers with the pattern of thermal ridges  820 . In this example, two sets of patterned thermal ridges  820  are disposed at the top left corner and bottom right corner of the rear enclosure  805 . Each pattern of thermal ridges  820  includes three separate and elongated ridges. A middle ridge is positioned diagonally from the corner of the rear enclosure  805  towards the center of the rear enclosure  805 . Left and right ridges are placed substantially parallel to the middle ridge. 
         [0037]      FIG. 9  includes an assembled view and a cross-sectional view of another embodiment of a thermal attachment  810  and rear enclosure  805 , such as that shown in  FIG. 8 . It should be noted that tight contact is generally made between the thermal attachment  810  and the rear enclosure  805  via the slots  815  and the thermal ridges  820 . To avoid air gaps, a conductive paste or epoxy (not shown) may be used to fill the gap between the thermal attachment  810  and the rear enclosure  805 . The conduction of heat in the Z direction may be limited, so that the temperature of the rear enclosure  805  is cool to the touch even when the VGA controller  125  ( FIG. 1 ) is hot. The thermal attachment  810  conducts heat generated within the top housing  105  ( FIG. 1 ) and intersperses thermal contacts to the X/Y plane of the thermal attachment  810 . Heat flow within the thermal attachment  810  can travel towards the thermal ridges  820  and slots  815  as indicated with arrow  830 . The thermal ridges  820  act as channels for heat to flow to the outside of the rear enclosure  805  as indicated with arrow  840 . These are positioned in areas where heat should be steered normally towards the cooler areas, such as the corners. In addition, heat flow can travel from the thermal attachment  810  to the inner surface  825  of the rear enclosure  805  as indicated with arrow  835 . It should be noted that the heat flow  840  is generally higher as compared to the heat flow  835 . 
         [0038]      FIG. 10  is a schematic view of another embodiment of a clamshell computer, such as that shown in  FIG. 1 , and is denoted generally by reference number  1000 . The design and architecture of the clamshell computer  1000  is similar to the clamshell  100  ( FIG. 2 ), which includes top housing  105 , LCD  205 , hinge  115 , base  110 , first VGA controller  125 , CPU  215 , main memory  225 , and link/port  210 . 
         [0039]    However, the clamshell computer  1000  further includes a second VGA controller  1005  at the base  110 . It is possible to have multiple VGA controllers in a computing system. For clamshell computers, a particular solution is called Hybrid™, SLI™ or CrossFire™. Physically distinct video controllers may be used together or individually to render 3D graphics. It may still be desirable to position the first VGA controllers at the top housing  105  and the second VGA controller  1005  at the base  110 . In any computing system designs, the thermal attachment and the rear enclosure mentioned can be used to dissipate heat generated at the top housing. 
         [0040]    This description has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments discussed, however, were chosen to illustrate the principles of the disclosure, and its practical application. The disclosure is thus intended to enable one of ordinary skill in the art to use the disclosure, in various embodiments and with various modifications, as is suited to the particular use contemplated. All such modifications and variation are within the scope of this disclosure, as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly and legally entitled.