Published online by Cambridge University Press: 21 February 2011
We report on the current status of room-temperature life testing of Nichia NLPB-500 blue light emitting diodes. So far, two tests have been completed. During the first 1000-h test, a constant current of 20 mA was maintained in all devices. During the second 1650 h test, groups of 3 or 4 devices were driven at currents ranging from 20 mA to 70 mA. Very little degradation has been observed in devices driven at normal conditions (20-30 mA), with a noticeable increase in degradation rate above 60 mA.