Abstract

The dependence of luminous efficacy on phosphor concentration and thickness for high-power white light-emitting-diode (WLED) lamps is investigated by employing three-dimensional ray-tracing simulations. The simulations show that the brightness or luminous efficacy of WLED lamps highly depends on the combination of phosphor concentration and phosphor thickness (or phosphor-matrix composite volume). The package with lower concentration and higher phosphor thickness has higher luminous efficacy because the light trapping efficiency is lower with the low phosphor concentration. At the correlated color temperature (CCT) value of around 4000 K, ray-tracing simulation and experimental results show 20% and 23% improvement in lumen, respectively, with a 1.8-mm-phosphor package over a 0.8-mm-phosphor package. A package with convex lens can improve the lumen output over flat lens, but this improvement is small, and it requires higher amount of phosphor, up to 25%, to achieve same CCT value.

© 2008 IEEE

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References

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  1. N. R. Tasker, R. N. Bhargava, J. Barone, V. Chhabra, V. Chabra, D. Dorman, A. Ekimov, S. Herko, B. Kulkarni, "Quantum-confined-atom-based nanophosphors for silid state lighting," Pro. SPIE (2003) pp. 133-141.
  2. R. Mueller-Mach, G. O. Mueller, M. R. Krames, "Phosphor materials and combinations for illumination grade white pcLED," Proc. SPIE (2003) pp. 115-122.
  3. A. Borbely, S. G. Johnson, "Performance of phosphor-coated light-emitting diode optics in ray-trace simulations," Opt. Eng. 44, 1113081-4 (2005).
  4. J. K. Kim, H. Luo, E. F. Schubert, J. Cho, C. Sone, Y. Park, "Strongly enhanced phosphor efficiency in GaInN white light emitting diodes using remote phosphor configuration and diffuse reflector cup," Jpn. J. Appl. Phys. 44, L649-L651 (2005).
  5. N. T. Tran, C. G. Campbell, F. G. Shi, "Study of particle size effects on an optical fiber sensor response examined with Monte Carlo simulation," Appl. Opt. 45, 7557-7566.
  6. H. C. van de Hulst, Light Scattering by Small Particles (Dover, 1981).
  7. M. I. Mishchenko, L. D. Travis, A. A. Lacis, Scattering, Absorption, and Emission of Light by Small Particles (Cambridge Univ. Press, 2002).
  8. Y.-C. Lin, J. P. You, Y. He, F. G. Shi, Packaging of Phosphor Based High Power White LEDs: Effects of Phosphor Concentration and Packaging Configuration .
  9. N. T. Tran, F. G. Shi, Effect of Phosphor Particle Size on Luminous Efficacy of Phosphor-Converted White LED .

2005 (2)

A. Borbely, S. G. Johnson, "Performance of phosphor-coated light-emitting diode optics in ray-trace simulations," Opt. Eng. 44, 1113081-4 (2005).

J. K. Kim, H. Luo, E. F. Schubert, J. Cho, C. Sone, Y. Park, "Strongly enhanced phosphor efficiency in GaInN white light emitting diodes using remote phosphor configuration and diffuse reflector cup," Jpn. J. Appl. Phys. 44, L649-L651 (2005).

Appl. Opt. (1)

Effect of Phosphor Particle Size on Luminous Efficacy of Phosphor-Converted White LED (1)

N. T. Tran, F. G. Shi, Effect of Phosphor Particle Size on Luminous Efficacy of Phosphor-Converted White LED .

Jpn. J. Appl. Phys. (1)

J. K. Kim, H. Luo, E. F. Schubert, J. Cho, C. Sone, Y. Park, "Strongly enhanced phosphor efficiency in GaInN white light emitting diodes using remote phosphor configuration and diffuse reflector cup," Jpn. J. Appl. Phys. 44, L649-L651 (2005).

Opt. Eng. (1)

A. Borbely, S. G. Johnson, "Performance of phosphor-coated light-emitting diode optics in ray-trace simulations," Opt. Eng. 44, 1113081-4 (2005).

Packaging of Phosphor Based High Power White LEDs: Effects of Phosphor Concentration and Packaging Configuration (1)

Y.-C. Lin, J. P. You, Y. He, F. G. Shi, Packaging of Phosphor Based High Power White LEDs: Effects of Phosphor Concentration and Packaging Configuration .

Other (4)

H. C. van de Hulst, Light Scattering by Small Particles (Dover, 1981).

M. I. Mishchenko, L. D. Travis, A. A. Lacis, Scattering, Absorption, and Emission of Light by Small Particles (Cambridge Univ. Press, 2002).

N. R. Tasker, R. N. Bhargava, J. Barone, V. Chhabra, V. Chabra, D. Dorman, A. Ekimov, S. Herko, B. Kulkarni, "Quantum-confined-atom-based nanophosphors for silid state lighting," Pro. SPIE (2003) pp. 133-141.

R. Mueller-Mach, G. O. Mueller, M. R. Krames, "Phosphor materials and combinations for illumination grade white pcLED," Proc. SPIE (2003) pp. 115-122.

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