Heat dissipation device

Abstract

A heat dissipation device includes a fan and a heat sink located at the air outlet of the fan. The heat sink includes a first fin set arranged at a central portion of the air outlet, and two second fin sets respectively arranged at a side portion of the air outlet. The first fin set includes a plurality of first fins with a first passage defined between each two neighboring first fins. Each of the second fin sets includes a plurality of second fins with a second passage defined between each two neighboring second fins. Each of the second fin sets defines an undercut near the air outlet of the fan. The first passages communicate with the central portion of the air outlet of the fan. Each of the undercuts of the second fin sets communicates with corresponding side portion and corresponding second passage.

1 . A heat dissipation device comprising:
 a fan defining an air outlet at one side thereof, the air outlet comprising a first portion and two second portions, air pressure in each of the second portions being larger than air pressure of the first portion; and   a heat sink being located at the air outlet of the fan, the heat sink comprising a first fin set arranged at the first portion, two second fin sets respectively arranged at the second portions, the first fin set comprising a plurality of first fins stacked together with a first passage being defined between each two neighboring first fins, each of the second fin sets comprising a plurality of second fins stacked together with a second passage being defined between each two neighboring second fins, each of the second fin sets defining an undercut near the air outlet of the fan, the first passages communicating with the first portion of the air outlet of the fan, each of the undercuts of the second fin sets communicating with corresponding second portion and corresponding second passage.   
     
     
         2 . The heat dissipation device of  claim 1 , further comprising a heat pipe, wherein the heat sink defines a through groove to receive the heat pipe, the through groove being U-shaped and communicating with the air outlet of the fan. 
     
     
         3 . The heat dissipation device of  claim 1 , wherein each first fin comprises a first main body and a pair of first flanges bent horizontally from a top and a bottom of the first main body, each first flange being abutted with a first flange of a neighboring fin, the first passage being formed between every two adjacent fins. 
     
     
         4 . The heat dissipation device of  claim 3 , wherein each of the second fins comprises a second main body and an extending portion extending from the second main body, each of the undercuts being defined below the extending portions and between the second main bodies and the air outlet of the fan. 
     
     
         5 . The heat dissipation device of  claim 4 , wherein each of the second fins is L-shaped and has a pair of second flanges bent horizontally from a top and a bottom of the second main body and the extending portion. 
     
     
         6 . The heat dissipation device of  claim 1 , wherein the fan is a centrifugal fan, the first portion being a central portion of the air outlet, the second portions being located at two opposite sides of the air outlet. 
     
     
         7 . A heat dissipation device comprising:
 a centrifugal fan defining an air outlet at one side thereof; and   a heat sink being located at the air outlet of the fan, the heat sink comprising a first fin set arranged at a central portion of the air outlet, two second fin sets respectively arranged at two opposite side portions of the air outlet, the first fin set comprising a plurality of first fins stacked together with a first passage being defined between each two neighboring first fins, each of the second fin sets comprising a plurality of second fins stacked together with a second passage being defined between each two neighboring second fins, each of the second fin sets defining an undercut near the air outlet of the fan, the first passages communicating with the central portion of the air outlet of the fan, each of the undercuts of the second fin sets communicating with corresponding side portion of the air outlet of the fan and the corresponding second passage.   
     
     
         8 . The heat dissipation device of  claim 7 , further comprising a heat pipe, wherein the heat sink defines a through groove to receive the heat pipe, the through groove being U-shaped and communicating with the air outlet of the fan. 
     
     
         9 . The heat dissipation device of  claim 7 , wherein each first fin comprises a first main body and a pair of first flanges bent horizontally from a top and a bottom of the first main body, each first flange being abutted with a first flange of a neighboring fin, the first passage being formed between every two adjacent fins. 
     
     
         10 . The heat dissipation device of  claim 9 , wherein each of the second fins comprises a second main body and an extending portion extending from the second main body, each of the undercuts being defined below the extending portions and between the second main bodies and the air outlet of the fan. 
     
     
         11 . The heat dissipation device of  claim 10 , wherein each of the second fins is L-shaped and has a pair of second flanges bent horizontally from a top and a bottom of the second main body and the extending portion.