Heat sink with cooling channel

Abstract

A heat sink apparatus is provided with a cooling channel which directs cooling air between groups of fins on either side of the cooling channel to a location adjacent that of an electronic device to be cooled. The increase in cooling efficiency achieved by providing cooling air to the critical location of the electronic device more than offsets any loss in cooling efficiency due to the elimination of fins required for creation of the cooling channel. Thus a heat sink apparatus can be designed providing increased cooling to selected locations without the use of heat pipes or the like.

What is claimed is:  
     
         1 . A heat sink apparatus, comprising: 
 a base having first and second ends;    a plurality of fins extending upward from the base; and    a cooling channel defined between first and second groups of the fins, the cooling channel extending from the first end toward a location for an electronic device, the cooling channel having a channel width greater than a spacing between adjacent fins within each of the first and second groups, the cooling channel terminating upstream of the location for the electronic device.    
     
     
         2 . The apparatus of  claim 1 , wherein: 
 the plurality of fins includes intermediate fins located above the location for the electronic device in the path of the cooling channel, so that cooling air is directed by the cooling channel along the intermediate fins.    
     
     
         3 . The apparatus of  claim 1 , wherein: 
 the first and second ends of the base define a length of the base therebetween, the base having a width less than the length; and    the fins extend parallel to the length of the base.    
     
     
         4 . The apparatus of  claim 1 , wherein the channel width is at least 7 mm.  
     
     
         5 . The apparatus of  claim 1 , wherein the channel width is at least 10 mm.  
     
     
         6 . The apparatus of  claim 1 , wherein the channel width is at least three times the greatest spacing between adjacent fins within each of the groups of fins.  
     
     
         7 . The apparatus of  claim 6 , wherein the cooling channel has a channel length at least one-half a distance from said first end to said location.  
     
     
         8 . The apparatus of  claim 1 , wherein the cooling channel has a channel length at least one-half a distance from said first end to said location.  
     
     
         9 . The apparatus of  claim 8 , wherein the channel length is at least 75% of the distance from said first end to said location.  
     
     
         10 . The apparatus of  claim 1 , wherein the cooling channel has a channel length at least one-half the length of the base between the first and second ends.  
     
     
         11 . The apparatus of  claim 1 , wherein the cooling channel is defined by an area on the base which area has no fins.  
     
     
         12 . The apparatus of  claim 1 , wherein the cooling channel is defined by an area on the base having fins of shorter height than the fins of the groups of fins.  
     
     
         13 . The apparatus of  claim 1 , wherein design parameters of the apparatus are such that a loss in cooling efficiency resulting from the presence of the cooling channel, as contrasted to having additional fins in the area of the cooling channel like the fins of the groups, is more than offset by an increase in cooling efficiency due to cooler air being channeled to the location of the electronic device.  
     
     
         14 . The apparatus of  claim 1 , wherein the heat sink is at least partially constructed from a graphite material  
     
     
         15 . The apparatus of  claim 1 , further comprising insulating walls defining sides of the cooling channel.  
     
     
         16 . The apparatus of  claim 1 , in combination with: 
 a cooling fan oriented to direct cooling air across the heat sink from the first end toward the second end of the base; and    an electronic device in heat transfer communication with the location on the base, so that heat from the electronic device is transferred by the heat sink from the electronic device to the cooling air.    
     
     
         17 . A heat sink apparatus, comprising: 
 a base having a length and a width, the length being at least three times the width; and    a plurality of parallel fins extending from the base parallel to the length of the base, the fins including first and second groups separated by a cooling channel extending from one end of the base at least one-half the length of the base and less than the entire length of the base.    
     
     
         18 . The apparatus of  claim 17 , wherein: 
 the plurality of fins includes intermediate fins located in the path of the cooling channel above a location for an electronic device, so that cooling air is directed by the cooling channel to the intermediate fins.    
     
     
         19 . The apparatus of  claim 17 , wherein the cooling channel has a channel width of at least 7 mm.  
     
     
         20 . The apparatus of  claim 17 , wherein adjacent fins of each group are spaced apart by less than 5 mm.  
     
     
         21 . The apparatus of  claim 17 , wherein the cooling channel is defined by an area on the base which area has no fins.  
     
     
         22 . The apparatus of  claim 17 , wherein the cooling channel is defined by an area on the base having fins of shorter height than the fins of the groups of fins.  
     
     
         23 . A heat sink apparatus, comprising: 
 a base having a length; and    a plurality of parallel fins extending from the base, the plurality of parallel fins including first and second outer groups of fins extending the entire length of the base, and a third intermediate group of fins extending less than the entire length of the base, so that a cooling channel is defined between the first and second outer groups of fins in an area of the base not covered by the third intermediate group of fins.    
     
     
         24 . The apparatus of  claim 23 , wherein the plurality of parallel fins has an equal spacing within each of the first, second and third groups.  
     
     
         25 . The apparatus of  claim 23 , wherein the cooling channel has a channel length at least one half the length of the base.  
     
     
         26 . The apparatus of  claim 23 , wherein design parameters of the apparatus are such that a loss in cooling efficiency resulting from the presence of the cooling channel, as contrasted to having additional fins in the area of the cooling channel like the fins of the groups, is more than offset by an increase in cooling efficiency due to cooler air being channeled to the location of the electronic device.  
     
     
         27 . A method of cooling an electronic device, comprising: 
 providing a heat sink having first and second groups of fins and having a cooling channel defined between the first and second groups;    placing the electronic device in heat transfer communication with a location on the heat sink;    channeling cooling air through the cooling channel to the location of the electronic device; and    cooling the electronic device by transferring heat from the electronic device to the cooling air via the heat sink.    
     
     
         28 . The method of  claim 27 , further comprising: 
 providing more densely packed fins on the heat sink at the location of the electronic device than are provided upstream of the location.