Abstract:
Computing devices, including laptop computers, desk top computers, servers and video game terminals employ microprocessors which generate considerable heat. In fact, the heat generated from microprocessors is generally considered the limiting factor in computing speed. A heat sink is provided in thermal contact with a microprocessor whereby a water barrier is applied to and proximate a socket configured within the computing device&#39;s motherboard for preventing water of condensation from contacting areas covered by the water barrier.

Description:
PRIOR APPLICATIONS  
       [0001]     This is a continuation of application Ser. No. 11/031,930 filed on Jan. 10, 2005. 
     
    
     TECHNICAL FIELD OF INVENTION  
       [0002]     Computing devices, including laptop computers, desk top computers, servers and video game terminals employ microprocessors which generate considerable heat. In fact, the heat generated from microprocessors is generally considered the limiting factor in computing speed. A heat sink is provided in thermal contact with a microprocessor in cooperation with a water barrier applied to and proximate a socket configured within the computing device&#39;s motherboard for preventing water of condensation from contacting areas covered by the water barrier. Efficient refrigeration protocols are suggested to maximize heat dissipation.  
       BACKGROUND OF THE INVENTION  
       [0003]     As computing devices have become more powerful, microprocessor integrated circuits have become more sophisticated having increased clock speeds and computing power. As speeds increase, microprocessors operate at higher temperatures and, in fact, the single most important limiting factor in inhibiting computing speed is the thermal energy generated from such devices.  
         [0004]     Recognizing that heat generated from microprocessors limits the speed and resulting power of the computing device, efforts have been made to dissipate thermal energy. Most personal computers employ cooling fans integrated within the computer&#39;s chassis. However, cooling fans tend to be noisy and thus can represent a significant distraction to a user. Further, the mere passage of air over a microprocessor contained within the small confines of a personal computer is not a particularly efficient method of dispersing heat energy. Unless sufficient cooling is carried out, the heat generated by the microprocessor can cause it to overheat and damage the device.  
         [0005]     Recognizing that conventional fan-cooled computers represent a distraction and can cause a significant annoyance to a user affecting productivity, there have been attempts to deal with heat dissipation by means other than a fan. For example, in published application 2004/0156180, a large heat sink is employed as part of the computer chassis that contains the motherboard and hard drive. The heat sink is exposed to the external ambient air for heat dissipation while the motherboard and hard drive of the device are positioned within the chassis such that they are held tightly against the heat sink to allow the heat generated by the microprocessor and hard drive to be conducted to and dissipated by the heat sink. A further example can be found in U.S. Pat. No. 6,367,543 disclosing a housing which includes a lid having liquid flowing through ports located therein. A plurality of pins project outwardly from the bottom wall of the chamber, housing the active components of the device, in a staggered pattern whereby a thermal jacket is positioned over a liquid-held heat sink that does not directly engage the semiconductor package. The rather inefficient configuration taught by this reference is intended to reduce condensation that may form when operating at sub-ambient temperatures to reduce the risk of water damage to the interior of the cooled chamber. It is further taught that the outer surface of the thermal jacket is exposed to a sealant engaging the semiconductor element that remains at or near ambient temperature to minimize condensation on the surface of the thermal jacket.  
         [0006]     U.S. Pat. No. 6,725,682 shows a desk top type personal computer employing a cooling apparatus composed of three modules, namely, a heat exchanger, a chiller and a pump. The heat exchanger is mounted so as to be thermally coupled to a CPU microprocessor. In operation, fluid is pumped from a pump module through a chiller module and through a heat exchanger and is finally recirculated to the pump. When the cooling apparatus is operating, chilled fluid passes through the heat exchanger so as to extract heat produced by the microprocessor. It is taught that the body of the electronic device has protrusions that may be thermally coupled to the hot portion of the device to maintain it at a sufficient distance from the surface of the microprocessor so that sufficient ambient air may circulate therebetween so as to substantially prevent condensation from forming on the surface of the electronic device and from forming on and dripping from the heat exchanger when fluid is cooled to at least the dew point of the ambient air. Clearly, such a configuration reduces the effectiveness of the heat sink for direct contact between it and the electronic device to be cooled is avoided so as to prevent water of condensation from being created at or around the microprocessor.  
         [0007]     In light of the above discussion, it appears that several matters are well recognized in the prior art. Firstly, it is universally accepted that microprocessors, hard disk drives and other active components in a computing device must be cooled for limitations as to speed and computing power are limited by failure to dissipate heat, particularly from a microprocessor. Secondly, the prior art, although suggesting alternatives to traditional fan-based cooling devices, has suggested either non-optimal heat transfer configurations or limitations in cooling in order to minimize or entirely prevent water of condensation from adversely impacting the microprocessor and its surrounding topology.  
         [0008]     It is thus an object of the present invention to provide an efficient heat transfer assembly which eliminates the need for noise generating components such as air moving fans.  
         [0009]     It is a further object of the present invention to provide an effective heat transfer assembly which is not limited to a specific geometry or cooling temperature and which can be employed without damaging the microprocessor, its surrounding socket assembly and other components of the supporting motherboard.  
         [0010]     These and further objects will be more readily apparent when considering the following disclosure and appended claims.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention involves an assembly for use in a computing device such as a personal laptop computer, desk top computer, server or video game terminal. Each of these devices includes a microprocessor which generates heat during its operation. The invention includes the use of a heat sink in thermal contact with the microprocessor which is capable of providing a heat dissipating sink for removing thermal energy from the microprocessor much more effectively than devices of the prior art. The present invention includes applying a water barrier proximate the socket employed for making electrical connection to the microprocessor preventing water of condensation from contacting areas covered by the water barrier. Alternatively, the microprocessor can be encased within a shell having a fluid inlet and fluid outlet for recirculating coolant proximate the microprocessor and, if properly configured, the need for a water barrier applied to the socket and surrounding regions can be effectively eliminated. In either case, efficient refrigeration protocols are suggested to maximize heat dissipation.  
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0012]      FIG. 1  is a cross-sectional plan view of a microprocessor installed on a motherboard being cooled by fan generating circulating air; and  
         [0013]      FIGS. 2, 4  and  5  are cross-sectional plan views of various embodiments of the present invention; and  
         [0014]      FIG. 3  is a top plan view of a socket and supporting motherboard for accepting a microprocessor for use in practicing the present invention.  
         [0015]      FIG. 6  is a schematic diagram of an efficient heat transfer protocol for use in practicing the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     Turning first to  FIG. 1 , a cross-sectional view of a relevant area of a computing device  10  is shown. Specifically, motherboard  11  is depicted in partial cross-section supporting a microprocessor CPU  13  consisting of substrate  14  and die  15 . Microprocessor CPU  13  can be applied to supporting motherboard  11  either through a pin connection or by a flush connection over indented region  12 . That portion of motherboard  11  supporting microprocessor CPU  13  is shown in top plan view in  FIG. 3 . In this embodiment, pin receiving socket  31  having openings  32  for receiving the pins of substrate  14  (not shown) surrounds indented region  12 .  
         [0017]     Turning back to  FIG. 1 , a schematic depiction of a current cooling method commonly employed in laptop and desk top computers is shown. Specifically, fan  80  is caused to rotate by connecting a shaft to a motor (not shown) which can either be constantly engaged or periodically engaged through activation prompted by a thermo-couple or other thermal sensor located in the region of microprocessor CPU  13 . As the temperature of this device reaches a threshold value, fan  80  is engaged causing air flow schematically shown by arrows  81 . However, as noted previously, the activation of fan  80  is not only noisy and distracting to a user of the computing device but the mere passage of air in the directions of arrows  81  does not represent a particularly efficient means of cooling microprocessor CPU  13 .  
         [0018]     A first embodiment of the present invention can be readily visualized by reference to  FIG. 2 . As in the configuration depicted in  FIG. 1 , computing device  20  again consists of motherboard  11  supporting microprocessor CPU  13  which, in turn, consists of support  14  and die  15 . However, instead of employing fan  80 , a heat sink consisting of heat sink shell  16  having fluid inlet port  17  and fluid exit port  18  to facilitate the passage of a coolant such as water, alcohol, antifreeze or mixtures thereof to the interior of heat sink shell  16  is used. Heat sink shell  16  is in direct thermal contact with die  15 , directly, or through the use of a heat conductive film  25  of, for example, a silver based thermal grease.  
         [0019]     As noted previously, the prior art strongly suggests either refraining from adopting a configuration such as shown in  FIG. 2  or, if such a configuration is adopted, to limit the temperature of coolant passing within heat sink shell  16  so that the exterior surface of the heat sink shell does not drop below the surrounding dew point of the air within the computing device in order to avoid water of condensation from adversely affecting socket  31  and, perhaps, other active components on motherboard  11 .  
         [0020]     In practicing the present invention, the limitations suggested by the prior art limiting the temperature of heat sink shell  16  can be ignored. Specifically, applicant proposes, as a first embodiment, applying a water barrier proximate socket  31  in the areas where water of condensation is likely to appear and where such water of condensation, if not dealt with effectively, would compromise the computing device.  
         [0021]     It is suggested that several water barrier implementations can be employed in carrying out the present invention. For example, the water barrier can comprise a layer of dielectric grease which can be spread over the socket in areas  23  and within indented region  12  as shown as area  22  and over substrate  14  shown as area  24 . A suitable dielectric grease for use in carrying out the present invention is Luberex Dielectric Grease. Alternatively, a low viscosity liquid can be sprayed onto the socket and surrounding regions such as a silicone spray sold by Amsoil. As yet a further alternative, the entire motherboard  11  can be dipped within a fluid which can either remain in its fluid state or dried so long as its dielectric water barrier properties are maintained and electrical connections are not filled or otherwise blocked through the dipping process. Suitable fluids for dipping include latex and oil base paints which can also be brushed or sprayed in the socket region of computing device  20 . Further, commonly available household consumer products such as fingernail polish could be applied to socket region  31  and portions of substrate  14  as shown in  FIG. 2  in order to create the desired water barrier. In doing so, a user of the present invention need not be concerned with relative humidity or dew point temperature of the air within computing device  20  or the relative temperature of heat sink shell  16  in terms of water of condensation. Instead, heat shell  16  can be reduced to any desired temperature and thus provide an extremely effective expedient for drawing thermal energy from die  15  thus removing heat as a barrier to increased clock speeds and computing power.  
         [0022]      FIG. 4  represents yet another embodiment of the present invention. Specifically, computing device  40  again consists of motherboard  11  supporting microprocessor CPU  41  having substrate  14  and die  15  as shown. However, microprocessor CPU  41  can be encased within shell  42  either directly at the manufacturing facility where microprocessor CPU  41  is manufactured or as an aftermarket add on component. In this instance, inlet port  43  and outlet port  44  can again be employed to receive and circulate cooling fluid in the direction of arrows  19  and  21 . In employing this embodiment, thermal grease is no longer required as there is direct physical contact between the cooling fluid within space  45  and the heat generating die  15 . In practicing the embodiment shown in  FIG. 4 , a water barrier in terms of a dielectric grease or other expedient can be applied in the region proximate socket  31  including indented region  12  in the form of barrier  22 , substrate surface in the form of barrier  24  and the contact region between the substrate  14  and socket  31  in the form of barrier  23 .  
         [0023]      FIG. 5  depicts yet a further embodiment of the present invention. In this instance, computing device  50  again includes the depiction, in partial cross-section, of motherboard  11  focusing upon its socket region  31 . Microprocessor CPU  51  again is shown as consisting of substrate  14  which can include pin connections to pin openings  32  or could represent a flush mounted connection to socket region  31  which further supports die  15 . As in  FIG. 4 , a shell  54  is placed about microprocessor CPU  51  for receiving coolant through opening  52  and circulating coolant in area  45  to be expelled through opening  53  in the direction of arrows  19  and  21 . Thus, coolant fills region  45  thus acting as an effective heat sink for heat generating die  15 .  
         [0024]     The  FIG. 5  embodiment further includes outer shell  55  creating a space between it and shell  54 . In order to minimize the flow of water of condensation, an absorbent  53 , such as a cotton cloth, can be applied in this region thus absorbing water of condensation formed at the surface of shell  54  and thus preventing moisture from compromising socket  31  and its surrounding area. Although not shown, the embodiment of  FIG. 5  can also employ, as an additional expedient, the various water barriers discussed previously and applied to the socket and its proximity again, as shown and described with relation to  FIGS. 2 and 4 .  
         [0025]     As noted previously, the present invention can effectively reduce the temperature of a microprocessor CPU without the need to use conventional noise generating devices such as cooling fans. Further, because the heat sink and microprocessor can be positioned to abut one another, heat transfer from the die of the microprocessor CPU through the heat sink can be much more effective than competing devices taught in the prior art. Thus, the limitations placed upon computing devices through over heating of the microprocessor CPU can effectively be eliminated.  
         [0026]     Although there are a number of protocols useful in providing coolant to the recited heat sink, a preferred arrangement is shown schematically in  FIG. 6 . Specifically a continuous fluid path is shown feeding a coolant to a heat sink strategically located proximate CPU  100 . This fluid is maintained at the desired (low) temperature within reservoir  125  and circulated by means of pump  110 . Fluid within reservoir  125  is maintained at a predetermined temperature through the use of refrigeration unit  120  that circulates a refrigerant such as Freon through evaporator  115  consisting of heat transfer coils and an expansion valve (not shown).  
         [0027]     The present invention has been described fundamentally in terms of a computing device suggesting its application principally in the areas of laptop and desk top personal computers. However, applicant&#39;s invention can be used in such diverse areas as servers and video game terminals. Often times, servers are placed in a stacked relationship and positioned in a facility requiring aggressive air conditioning to reduce the ambient temperature of the facility well below that which would otherwise be necessary for human comfort. In other words, the active components within the server generating heat are dealt with by reducing the entire ambient surrounding temperature of the servers which represents an exceedingly inefficient use of energy. By employing the present invention, however, a server facility need not be air conditioned and suitable heat sinks such as those described above, can be employed only in those areas within each server requiring the dissipation of thermal energy.  
         [0028]     In view of the various embodiments to which the present invention may be applied, it is noted that the embodiments described herein are meant to be illustrative only and should not be taken as limiting the scope of the invention.