| As new generation of green light, the biggest advantage of LED is its high efficiency and long life compared to traditional light, which leads to broader prospects in general lighting application. However, it is a big challenge to test the long life and reliability of LED due to LED’s long life. Currently, most of LED chip manufactory claim that the LED life is more than50,000hours (5.7years) but it is hard for lab to evaluate if it is true or not in so long time. There for, it is important for Industry, Academia and End user to evaluate the LED life in reasonable time which meets the acceptable tolerance.In this paper, an industrial light-emitting diode life assessment method which is capable of forecasting long life of LED in short time is researched. This article firstly introduces the principle of this method. Firstly lumen output decay at regular interval is monitored by measuring the lumen output of a set of LED within certain time, then this set of lumen decay data was normalized, and the LED life is extrapolated by performing an exponential fit.In this paper, a life test platform which is applied to1W high power chip is set up to test the long life of a group of20LEDs. Measurement uncertainty about this prediction system and method is analysed. The acceptance of this system and method to predict the LED life is verified from both the respect of theory and testing result.Finally, the lives of some typical LED devices in market are predicted by using this method. These life data of typical LED devices has important reference value for semiconductor lighting industry and end user. |
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