US Patent 8230904 Heat dissipation device having a fan duct thereon

A heat dissipation device includes a heat sink, a fan placed on a top of the heat sink for providing an airflow through the heat sink and a fan duct located at a side of the heat sink. The heat sink includes a plurality of upwardly extending first fins and a plurality of laterally extending second fins located below the first fins. A plurality of first airflow channels are defined in the adjacent first fins and a plurality of second airflow channels are defined in the adjacent second fins. The fan duct guides a significant part of the airflow produced by the fan to the second airflow channels from a lateral side of the heat sink to have a sufficient contact with the second fins of the heat sink.