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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 15, Iss. 12 — Jun. 11, 2007
  • pp: 7572–7577

Precise optical model of multi-chip white LEDs

Wei-Ting Chien, Ching-Cherng Sun, and Ivan Moreno  »View Author Affiliations

Optics Express, Vol. 15, Issue 12, pp. 7572-7577 (2007)

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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.

© 2007 Optical Society of America

OCIS Codes
(230.3670) Optical devices : Light-emitting diodes
(350.4600) Other areas of optics : Optical engineering

ToC Category:
Optical Devices

Original Manuscript: April 16, 2007
Revised Manuscript: June 1, 2007
Manuscript Accepted: June 2, 2007
Published: June 5, 2007

Wei-Ting Chien, Ching-Cherng Sun, and Ivan Moreno, "Precise optical model of multi-chip white LEDs," Opt. Express 15, 7572-7577 (2007)

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