Statistical Analysis of Lumen Depreciation for LED Packages
M. Schuld (Consultants in Quantitative Methods (CQM))
B. Jacobs (Philips Lighting Research)
Willem Dirk van Driel – Editor (TU Delft - Electrical Engineering, Mathematics and Computer Science, Philips Lighting Research)
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Abstract
Commercial claims for LED-based products in terms of lumen maintenance are fully based on TM-21 extrapolations using LM-80 data. This chapter indicates that there may be a risk in doing this as TM-21 only relies on the behavior of the average LED degradation, instead of taking into account the degradation of all individual LEDs. Therefore, we propose a more profound statistical approach in order to make the appropriate step from TM-21 extrapolation to lumen maintenance on a product level. This is needed as some commercial claims are based on 10 years of warranty and some service bids provide periods of 20–25 years of operation. This chapter reviews the different approaches currently available to perform lumen maintenance extrapolations.