【摘 要】
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The degradation of luminous flux of LEDs is dependent on the type of LED and its operation conditions.That is why a prediction of lifetime often differs from case to case.Mostly,the testing times are
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The degradation of luminous flux of LEDs is dependent on the type of LED and its operation conditions.That is why a prediction of lifetime often differs from case to case.Mostly,the testing times are too short to reach 70 or 80 % of the beginning luminous flux.So extrapolation has to be used to predict the lifetime.In this study different methods and mathematical functions are compared.
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