Abstract:
Graphics card apparatus with improved heat dissipation and including a planar metallic cover plate having an external perimeter configuration that generally corresponds to the plan-form of the printed circuit board used in the graphics card assembly, a plurality of thermal transfer blocks that can be selectively affixed to sources of thermal energy on the graphics card assembly and thermally coupled to the cover plate, and a fan and carriage therefor comprised of a heat sink and flow directing structure. Heat generated by the active board elements is transferred to the thermal blocks, sinked in part to the cover plate and ultimately removed from blocks and plate by air flow drawn into and through thermal baffles or vanes in the cooling structure. The outer surface of the cover plate also provides a broad surface upon which the manufacturer or marketer can display artwork, trademarks or other decorative indicia.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to graphics card apparatus and more particularly to an improved graphics card assembly having a cosmetic cover plate and heat sink, individual heat transfer blocks, and a fan assembly including thermal transfer mass and flow directing baffles, or alternatively, a sub-assembly for addition to a graphics card, such sub-assembly including a cosmetic cover plate and heat sink, individual heat transfer blocks, and a fan and carriage therefor including thermal transfer mass and flow directing baffles. 
     BACKGROUND OF THE INVENTION 
     In order to enable desktop and other computers to rapidly process graphics and game technology, add-on units generally referred to as “graphics cards” or “VGA cards” are often installed in computer devices. Such cards include a separate processor, called a GPU, one or more memory chips, and other required circuitry, all mounted to a circuit board including an edge connector that is adapted to plug into an available slot in the associated computer device. Such cards often have extremely large computing power and, as a consequence, generate substantial heat that if not dissipated will adversely affect operation of the graphics card. Heretofore, various approaches have been tried to dissipate or otherwise remove heat from the thermal energy generating components and normally include some type of fan for blowing air across the active components, and perhaps some type of thermal mass capable of sinking the heat generated. To date, however, the efficiency of such devices has not been optimal. Furthermore, the design of such devices has not been aesthetically complimentary to the graphics card assembly from a marketing standpoint. There is thus a need for an improved heat extraction or dissipation mechanism, which can be added to a standard graphics card to efficiently remove thermal energy generated thereby. 
     SUMMARY OF THE PRESENT INVENTION 
     It is therefore a principal object of the present invention to provide a novel thermal energy dissipation apparatus which can be added to a graphics card to improve heat removal therefrom. 
     Another object of the present invention to provide a graphics card assembly having a sub-assembly including a cosmetic cover plate and heat sink, individual heat transfer blocks, and a fan and carriage therefor including thermal transfer mass and flow directing baffles. 
     Still another object of the present invention is to provide apparatus of the type described which, in addition to removing thermal energy from the graphics card components, also contributes to the overall cosmetic appearance of the graphics card assembly. 
     Yet another object of the present invention is to provide an apparatus of the type described including a cover plate having a large planar exterior surface upon which decorative graphics can be affixed, inscribed or otherwise placed as a means of improving customer appeal. 
     Briefly, a presently preferred embodiment of the present invention includes a planar metallic cover plate having an external perimeter configuration that generally corresponds to the plan-form of the printed circuit board used in the graphics card assembly to which it is to be affixed. The embodiment also includes a plurality of thermal transfer blocks that can be selectively affixed to sources of thermal energy on the graphics card assembly and thermally coupled to the cover plate. And finally, the embodiment includes a fan and carriage therefor comprised of a heat sink and flow directing structure. Heat generated by the active board elements is transferred to the thermal blocks, sinked in part to the cover plate and removed from blocks and plate by the airflow drawn into and forced through thermal baffles or vanes in the cooling structure. The outer surface of the cover plate also provides a broad surface upon which the manufacturer or marketer can display artwork, trademarks or other decorative indicia. 
     An important advantage of the present invention is that the cooling fan is asymmetrically disposed relative to the GPU, the principal heat generating unit, and a large part of the cooling fluid flow is passed over a heat sinking structure that is in direct thermal engagement with the GPU. 
     Another advantage of the present invention is that the thermal transfer blocks transfer thermal energy to the large cover plate as well as experience energy transfer to the airflow passing therethrough from the fan. 
     Still another advantage of the present invention is that the external cover plate provides a broad heat dissipating surface conforming to the principal plan-form of the VGA card and, in addition to removing thermal energy from the card, also provides a flat surface upon which decorative graphics can be displayed. 
     Yet another advantage of the present invention is that it provides a sub-assembly of components that can be arranged to suit a particular card design, there being substantially no limitations on the positioning of the several thermal transfer blocks. 
     A still further advantage of the present invention is that the cover plate provides for better capture of the thermal transfer blocks, better contact between the chips and the thermal transfer blocks, and better air flow management than in the prior art. 
     These and other objects of the present invention will no doubt become apparent to those skilled in the art after having read the following detailed description of preferred embodiments illustrated in the several figures of the drawing. 
    
    
     IN THE DRAWING 
     FIG. 1 is a perspective view showing a presently preferred embodiment of a graphics card assembly including a heat dissipating subassembly in accordance with the present invention; 
     FIG. 2 is an exploded perspective view showing the several components of the assembly illustrated in FIG. 1; 
     FIG. 3 a  is a plan view showing the top of the cover plate depicted in FIG. 2; 
     FIG. 3 b  is a perspective view showing the bottom of the cover plate depicted in FIG. 3 a  with the fan carriage and risers affixed thereto; 
     FIG. 4 is a perspective view illustrating the topside of the fan carriage and flow directing sink block structure illustrated in FIG. 2; 
     FIG. 5 is a perspective view illustrating a thermal transfer block; 
     FIG. 6 is an assembly view shown in plan form with the cover plate and transfer blocks partially broken away to reveal internal detail; 
     FIG. 7 is an elevational view taken along the line  7 — 7  of FIG. 6; 
     FIG. 8 is a perspective view illustrating an alternative form of cover plate; and 
     FIG. 9 is a perspective view illustrating another alternative form of cover plate. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1 of the drawing, a graphics card assembly in accordance with the present invention is illustrated at  10  and includes a printed circuit board  12  having edge connectors  14  and populated with numerous electronic components some of which are shown at  16 . The board is attached at the near end to an end plate  18  carrying various cabling connectors  20 ,  21  and  22  used to communicate signals into and out of the assembly. Affixed to the printed circuit board  12  by means of three vertically extending spacing legs or risers, one of which is shown at  24 , is a planar, generally rectangular metal cover plate  26  having a circular aperture  28  cut therein. The foremost extremity of plate  26  includes a laterally extending tab  30  conforming to a similar tab on the board  12 . The front edge of the plate  26  is captured beneath a turned back lip  32  forming a side of the end plate  18 . Disposed beneath plate  26  and carried thereby is a metal fan carrier, heat sink and flow director apparatus  34  that is affixed to the bottom side of plate  26  by means of three screws (not shown). Positioned within the aperture  28  and affixed to and carried by the carrier  34  is a fan unit  36 . Note that the upper surface of plate  26  is flat and ideally suited for decorative graphics, manufacturers or marketers trademarks, etc. 
     In use, the graphics card assembly is oriented so as to have the near right side of the assembly, as depicted, facing a slot on a computer motherboard and mounted thereto by slipping the edge connectors  14  into the slot so that the assembly communicates with devices on the motherboard via the edge connector  14 . AS described in more detail below, heat generated by the electronics components of the assembly are sinked to transfer blocks (not shown), the plate  26 , and the carrier  34 , all of which are cooled by air flow created by the fan 36 , as will also be further elucidated below. 
     In FIG. 2, the cover plate  26 , risers  24  and fan carrier  34  are shown exploded away from the populated graphics card  12 . For clarity, the fan  36  shown in FIG. 1 is not shown installed to its carrier  34 . The particular graphics card illustrated is a model NV  30  sold by eVGA.com Corporation of Brea, CA. A pair of copper contact plates  40  and  41  shown above and below carrier  34 , and four thermal transfer blocks  42 - 48  are also shown above graphics card  12 . As will be further explained below, the transfer blocks are positioned to intimately engage the top surfaces of heat generating, active electronic components that are not shown but will be positioned at  50 ,  52 ,  54  and  56  on card  12 . Similarly, a graphics processor unit (GPU) will be mounted to card  12  at  58  and the top surface thereof will be engaged by the contact plate  41  that is soldered or brazed to, or molded into the bottom of carrier  34 . The other copper plate  40  is soldered or brazed to the top edges of the flow directing vanes  62  as will be further explained below. 
     The fan carrier  34  (with fan installed thereto—not shown) is aligned with the opening  28  and mounted to the bottom of cover plate  26  by three screws  72  passed through openings  74 ,  74  and  77 , and threaded into threaded bores  76  tapped into the top of carrier  34 . The copper plate  40  is attached to the top edges of the vanes  62  and engages the bottom of cover plate  26  to transfer thermal energy from the carrier  34  to the cover plate. As pointed out above, the second copper contact plate  41  affixed to the bottom surface of fan carrier  34  will physically engage the top of the GPU to be mounted at  58  in order to transfer heat therefrom to carrier  34 . 
     As will also be further discussed below, the height of each one of the thermal transfer blocks  42 - 48  is such as to substantially span the distance between the top of a corresponding active element mounted to board  12  and the bottom surface of cover plate  26 . Any gap remaining is closed by an appropriate thermally conductive compound. Plate  26  is secured to board  12  by means of the capture of edge  31  beneath lip  32  of the board end plate  18 , and a force fit of the upper ends of risers  24  to openings  25  in cover plate  26 . The lower ends of risers  24  are secured to board  12  by means of appropriate mounting screws  27  or other suitable fasteners. Plate  26  is prevented from bowing upwards and is in fact held in secure engagement with the tops of the blocks  42 - 48  by means of spring clips  61  and  63 , respectively passed through openings  68  and  70  formed in plate  26 , bores  64  and  66  formed on carrier  34 , and corresponding openings formed in board  12 . 
     In FIG. 3 a,  the upper surface of cover plate  26  is illustrated in plan-form to more clearly show the perimeter configuration as well as the location of apertures  25 ,  28 ,  68 ,  70  and  74 . In the illustrated embodiment plate  26  is made of sheet aluminum but alternatively could be made of steel, copper or any other suitable material capable of serving as a heat sink. 
     FIG. 3 b  is included to show the bottom sides of both the plate  26  and the fan carrier and heat sink  34  as well as the stand off legs  24 . Note also the copper plate  41  which in the preferred embodiment is molded into the bottom of carrier  34 . Alternatively it could be soldered or brazed to the bottom of carrier  34 . 
     Turning now to FIG. 4 of the drawing, the upper side of the fan carrier, flow director and heat sink  34 , and its associated thermal transfer plate  40  are illustrated. Note that carrier  34  is a single molded unit having integrally formed thermal baffles or vanes  62  standing up from a base portion  80  that is surrounded in part by an integrally formed side frame  82  that partially circumscribes the circular opening  84  through which the fan  36  (FIG. 1) draws (or alternatively exhausts) cooling air. The fan is mounted to carrier  34  by means of screws (not shown) threaded into or passing through apertures  86 , one of which is illustrated. Also depicted in this view are the threaded openings  76  for facilitating mounting of the carrier to cover plate  26 , and the cylindrical bores  64  and  66  that align with the openings  68  and  70  (FIG. 2) of plate  26  and receive the spring clips  61  and  63 . Lying on top of the vanes  62  and positioned directly above the position of the GPU engaging plate  41  (not shown) is the copper contact plate  40  which engages and serves to transfer thermal energy passing through the vanes  62  to plate  26 . 
     In FIG. 5, an exemplary form of a simple thermal transfer blocks that might be used as one of the thermal transfer blocks  42 - 48  is shown at  42 . In one embodiment, the blocks may be formed from an extruded section of, preferably, copper metal. However, any material having good thermal conducting characteristics may be used. The illustrated block has four elongated openings  90  passing therethrough for receiving air flow induced by the fan  36  (FIG.  1 ). The bottom surface  92  is planar and intended to physically engage the top surface of an active electronic element mounted on PC board  12  and transfer thermal energy therefrom. Similarly, the top surface  94  is planar and intended to engage the bottom surface of plate  26  either directly or via an appropriate heat transferring compound deposited therebetween. Air flowing through the openings or passageways  90 , as well as around the sides of the block, tends to remove thermal energy as it propagates through the block from bottom to top to be sinked to cover plate  26 . 
     In FIG. 6, the assembled card apparatus is shown from the top with the cover plate  26  partially broken away to reveal the fan carrier  34  and the thermal transfer blocks  42 - 48  in place on the card  12 . Note that the fan  36  is asymmetrically positioned relative to the GPU (not shown, but positioned on the board  12  beneath the plate  40 ) so that heat transferred from the top surface of the GPU is conducted into the bottom surface of carrier  34  (via plate  41 ) and transferred to the base of the carrier  34  and thence to the vanes  62  which in turn transfer heat to plate  40  which in turn couples it to cover plate  26 . Air drawn in through cover plate opening  28  by the fan  36  (FIG. 1) is directed through the vanes  62 , drawing with it heat transferred from the bottom plate of carrier  34 , the vanes  62 , the bottom of plate  40 , and the bottom surface of cover plate  26  before it is caused to flow through and around the thermal transfer blocks  42 - 48 , and thence be discharged to the sides of the card assembly from beneath plate  26 . 
     Alternatively, fan  36  could be reversed to draw air in from the open sides of the assembly through the vanes  62  and be exhausted out through the opening  28  in cover plate  26 . Flow in this direction would likewise induce airflow through the passages in blocks  42 - 48 , and may be preferable for some applications where the thermal energy generated by the components beneath the transfer blocks  42 - 48  is substantially less than the thermal energy generated by the GPU. 
     The positioning of the fan carrier  34  and blocks  42 - 48 , as well as their relationship to plate  26  is additionally shown in FIG. 7 which is a cross-section taken along the line  7 - 7  in FIG.  6 . Note that the gap  90 , if any, between the heat transfer blocks  46 ,  48  (as well as the blocks )  42 ,  44  will normally be filled with a suitable heat transfer compound so that thermal energy is transferred to cover plate  26  to assist in the dissipation of generated energy. 
     Although the present invention has been described above in terms of particular embodiments illustrated in the several figures of the drawing, it will be appreciated that other configurations of fan carrier, flow directing vanes, thermal transfer blocks and cover plates may be utilized without departing from the essence of the present invention. For example, ribs, vanes or even simple grooves or corrugations may be provided in plate  26  in order to increase the surface area thereof. Furthermore, plate  26  may be comprised of multiple layers joined together by ribs (FIG. 8) or a flat plate combined with a corregated plate (FIG. 9) such that a flow of air therethrough is induced by fan  28  to further increase the transfer and exhaust of thermal energy from the graphics card assembly. Such configurations may be of particular interest in the case where the fan is operated in the reverse direction referred to above such that air is drawn from the perimeter of the assembly across the various components and heat transfer elements and the exhausted through passageways formed between the sandwiched plates. 
     Notwithstanding that the present invention has been described above in terms of several alternative embodiments, it is anticipated that still other alterations and modifications will become apparent to those skilled in the art after having read this disclosure. It is therefore intended that such disclosure be considered illustrative and not limiting, and that the appended claims be interpreted to include all such alterations, modifications and embodiments as fall within the true spirit and scope of the invention.