COOLED LIGHT EMITTING APPARATUS

摘要

A cooled light emitting apparatus 1 comprises a light source including a clo se packed array 2 of light emitting diode devices (high intensity LEDs) and a cooling system for cooling the light source. The cooling system comprises a thermoelectric cooling device in the form of a Peltier device 4 connected vi a a heat spreader 3 to the light source and a heat exchange system 5, 6 for removing heat from the Peltier device 4. The heat exchange system 5,6 uses liquid coolant (or refrigerant) to cool the Peltier device 4. By extracting heat from the LED array 2 at a rate greater than 5W cm-2 it is possible to maintain the LED array at a temperature of less than -10 degrees Celsius, an d thus emit light having an optical power density of greater than 1Wcm-2.