High brightness light emitting diodes have been used to develop high illuminance headlight for medical applications. It
provides various advantages such as high illuminance, long life time, reduced infra red light, extended operation time
with battery and light weight. A 3 W LED was employed to achieve the high performance medical headlight. The optical
design includes two lenses for high energy transmission and high illuminance. The LED headlight shows 42,000 lux with
spot diameter of 80 mm at the distance of 300 mm. For comparison purpose, 5 W LED was also used to obtain the high
illuminance headlight. However, the large divergence angle and large spot size of the 5 W LED limits the illuminance to
31,000 lux with increased burden on heat dissipation. The thermal images of the heat sinks indicate that the temperature
of the headlight using a 3 W LED is below 50 degree C, which is suitable for medical applications.