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Proceedings Paper

A precise optical model of phosphor-based multi-chip white LEDs
Author(s): Wei-Ting Chien; Tsung-Xian Lee; Shin-Xing Ma; Ching-Cherng Sun; Ivan Moreno
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Paper Abstract

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.

Paper Details

Date Published: 14 September 2007
PDF: 6 pages
Proc. SPIE 6669, Seventh International Conference on Solid State Lighting, 66690N (14 September 2007); doi: 10.1117/12.733326
Show Author Affiliations
Wei-Ting Chien, National Central Univ. (Taiwan)
Tsung-Xian Lee, National Central Univ. (Taiwan)
Shin-Xing Ma, National Central Univ. (Taiwan)
Ching-Cherng Sun, National Central Univ. (Taiwan)
Ivan Moreno, National Central Univ. (Taiwan)
Univ. Autonoma de Zacatecas (Mexico)


Published in SPIE Proceedings Vol. 6669:
Seventh International Conference on Solid State Lighting
Ian T. Ferguson; Nadarajah Narendran; Tsunemasa Taguchi; Ian E. Ashdown, Editor(s)

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