Thermacore International Inc., Global Leader in Thermal Management. As electronic devices decrease in size and increase in power, the required heat sinks have grown to be larger than the devices.
Heat sinks are most efficient when there is a uniform heat flux applied over the entire base.
The higher the power, the smaller the source, and the farther the source is off-center, the greater the thermal spreading resistance as shown below. The brute force approach to overcoming spreading resistance is to increase the size of the heat sink, increase the thickness of the base, increase the airflow, or decrease the incoming air temperature. These steps increase weight, noise, system complexity, and expense. They operate in the same way conventional heat pipe heat sinks do, through a two-phase heat transfer process. As heat is applied to the base, the working fluid at that location immediately vaporizes, and the vapor rushes to fill the vacuum.