Precise optical model of multi-chip white LEDs

Wei Ting Chien, Ching Cherng Sun, Ivan Moreno

Research output: Contribution to journalArticlepeer-review

91 Scopus citations


A single-chip white light LED is commonly modeled by considering the phosphor coating as a homogeneous Lambertian light source. However, this approach leads to an incorrect optical simulation of phosphor-coated multi-chip LEDs due to the presence of a previously unreported spatial distribution of emission spots across the phosphor layer. We introduce "weighting" factors based on position-dependent light strength across the phosphor surface in order to improve the model accuracy. Following the modeling algorithm in the mid-field region, we have built up a precise and practical optical model by using Monte Carlo ray tracing and weighting factors. We measure the LED radiation distribution at several representative distances to test the model performance. In all cases, the accuracy is higher than 99.5% in normalized cross correlation between the simulated pattern and experimental measurement.

Original languageEnglish
Pages (from-to)7572-7577
Number of pages6
JournalOptics Express
Issue number12
StatePublished - 11 Jun 2007


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