Thermal management of high-power LEDs

Thus, thermal management of high power LEDs is a crucial area of the research and development.

Limiting both the junction and the phosphor particles temperatures to a low value is required, which will guarantee desired LED lifetime.

Typically, LEDs are encapsulated in a transparent polyurethane-based resin, which is a poor thermal conductor.

[4] Heat is generated from the p–n junction by electrical energy that was not converted to useful light, and conducted to outside ambience through a long path, from junction to solder point, solder point to board, and board to the heat sink and then to the atmosphere.

Power LEDs are often mounted on metal-core printed circuit boards (MCPCB), which will be attached to a heat sink.

Currently, the most common solution is to use a phase-change material, which is applied in the form of a solid pad at room temperature, but then changes to a thick, gelatinous fluid once it rises above 45 °C.

[12] N-type and p-type thermoelectric units are connected sequentially in series as the middle layer.

With an applied external current, the heat will then be forced to flow to the bottom substrate through the thermoelectric units so that the temperature of the high power LED can be stable.

Liquid cooling systems are made up of a driving pump, a cold plate, and a fan-cooled radiator.

[14] The heat generated by a high power LED will first transfer to liquids through a cold plate.