Heat dissipating device for an electronic component

Abstract

A heat dissipating device includes a lower heat sink unit and an upper heat sink unit stacked above the lower heat sink unit. The lower heat sink unit includes a base and a plurality of parallel fins extending from the base. Each of the fins has a top end distal from the base. The fins include a set of first fins and a set of second fins. Each of the first fins has a horizontal cross-section greater than that of each of the second fins. Each two adjacent ones of the first fins confine a horizontal spacing greater than that of each two adjacent ones of the second fins.

We claim:  
     
         1 . A heat dissipating device comprising: 
 a lower heat sink unit including a horizontally extending lower base and a plurality of spaced apart lower fins fixed to and extending upwardly from said lower base, each of said lower fins having a top end distal from said lower base; and    an upper heat sink unit stacked above said lower heat sink unit and including a horizontally extending upper base that is fixed to said top ends of at least some of said lower fins, and a plurality of spaced apart upper fins fixed to and extending uprightly from said upper base;    wherein said lower fins include a set of parallel first lower fins and a set of second lower fins that are parallel to said first lower fins, each of said first lower fins having a horizontal cross-section greater than that of each of said second lower fins, each two adjacent ones of said first lower fins confining a horizontal spacing greater than that of each two adjacent ones of said second lower fins.    
     
     
         2 . The heat dissipating device of  claim 1 , wherein each of said first lower fins has a height greater than that of each of said second lower fins, said upper base being fixed to said top ends of said first lower fins.  
     
     
         3 . The heat dissipating device of  claim 1 , wherein each of said second lower fins is an elongated thin plate, said horizontal cross-section of each of said first lower fins being substantially elliptical in shape.  
     
     
         4 . The heat dissipating device of  claim 1 , wherein each of said second lower fins is an elongated thin plate, said horizontal cross-section of each of said first lower fins being rectangular in shape.  
     
     
         5 . The heat dissipating device of  claim 2 , wherein said second lower fins include left and right sets of said second lower fins, said first lower fins being disposed between said left and right sets of said second lower fins.  
     
     
         6 . The heat dissipating device of  claim 1 , wherein said upper fins are parallel to each other, each of said upper fins being an elongated thin plate.  
     
     
         7 . The heat dissipating device of  claim 6 , wherein each of said upper fins has a horizontal cross-section that is substantially elliptical in shape.  
     
     
         8 . The heat dissipating device of  claim 6 , wherein said upper fins are arranged in an array of parallel rows, said upper fins in adjacent ones of said rows being staggered relative to each other.  
     
     
         9 . The heat dissipating device of  claim 6 , wherein said upper base has opposite first and second sides and opposite top and bottom ends, each of said first and second sides being formed with an inclined side face extending inclinedly and inwardly from said bottom end to said top end of said upper base.  
     
     
         10 . The heat dissipating device of  claim 1 , wherein each of said upper fins is in the form of a pin.