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Virtual Journal for Biomedical Optics

Virtual Journal for Biomedical Optics


  • Editor: Gregory W. Faris
  • Vol. 5, Iss. 11 — Aug. 25, 2010

Approach for optimization of the color rendering index of light mixtures

Ku Chin Lin  »View Author Affiliations

JOSA A, Vol. 27, Issue 7, pp. 1510-1520 (2010)

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The general CIE color rendering index (CRI) of light is an important index to evaluate the quality of illumination. However, because of the complexity in measurement of the rendering ability under designated constraints, an approach for general mathematical formulation and global optimization of the rendering ability of light emitting diode (LED) light mixtures is difficult to develop. This study is mainly devoted to developing mathematical formulation and a numerical method for the CRI optimization. The method is developed based on the so-called complex method [ Computer J. 8, 42 (1965) ; G. V. Reklaitis et al., Engineering Optimization—Methods and Applications (Wiley, 1983) ] with modifications. It is first applicable to 3-color light mixtures and then extended to a hierarchical and iterative structure for higher-order light mixtures. The optimization is studied under the constraints of bounded relative intensities of the light mixture, designated correlated color temperature (CCT), and the required approximate white of the light mixture. The problems of inconsistent constraints and solutions are addressed. The CRI is a complicated function of the relative intensities of the compound illuminators of the mixture. The proposed method requires taking no derivatives of the function and is very adequate for the optimization. This is demonstrated by simulation for RGBW LED light mixtures. The results show that global and unique convergence to the optimal within required tolerances for CRI and spatial dispersivity is always achieved.

© 2010 Optical Society of America

OCIS Codes
(330.1710) Vision, color, and visual optics : Color, measurement
(330.1715) Vision, color, and visual optics : Color, rendering and metamerism

ToC Category:
Vision, Color, and Visual Optics

Original Manuscript: September 23, 2009
Revised Manuscript: April 2, 2010
Manuscript Accepted: April 7, 2010
Published: May 28, 2010

Virtual Issues
Vol. 5, Iss. 11 Virtual Journal for Biomedical Optics

Ku Chin Lin, "Approach for optimization of the color rendering index of light mixtures," J. Opt. Soc. Am. A 27, 1510-1520 (2010)

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  1. Y. Ohno, “Optical metrology for LEDs and solid state lighting,” Proc. SPIE 6046, 604625 (2006). [CrossRef]
  2. A. Zukauskas, F. Ivanauskas, R. Vaicekauskas, M. S. Shur, and R. Gaska,“Optimization of multichip white solid-state lighting source with four or more LEDs,” Proc. SPIE 4445, 148–155 (2001). [CrossRef]
  3. H. Ries, I. Leike, and J. Muschaweck, “Optimized additive mixing of colored light-emitting diode sources,” Opt. Eng. (Bellingham) 43, 1531–1536 (2004). [CrossRef]
  4. T-h. Hsu, “Optimization on color characteristics for LED lighting system,” M.S. thesis (National Central University, Taiwan, 2005).
  5. X. Guo and K. W. Houser, “A review of colour rendering indices and their application to commercial light sources,” Light. Res. Technol. 36, 183–197 (2004). [CrossRef]
  6. CIE, Method of Measuring and Specifying Colour Rendering Properties of Light Sources, Publication 13.3 (Commission Internationale de l’Eclairage, Vienna, 1995). ISBN 978-3900734572.
  7. W. Davis and Y. Ohno, “Toward an improved color rendering metric,” Proc. SPIE 5941, 59411G (2005). [CrossRef]
  8. S. Boissard and M. Fontoynont, “Optimization of LED-based lighting blendings for object presentation,” Color Res. Appl. 34, 310–320 (2009). [CrossRef]
  9. R. Mirhosseini, M. F. Schubert, S. Chhajed, J. Cho, J. K. Kim, and E. F. Schubert, “Improved color rendering and luminous efficacy in phosphor-converted white light emitting diodes by use of dual-blue emitting active regions,” Opt. Express 17, 10806–10823 (2009). [CrossRef] [PubMed]
  10. S. P. Ying, C.-W. Tang, and B.-J. Huang, “Characterizing LEDs for mixture of colored LED light sources,” International Conference on Electronic Materials and Packaging, EMAP 2006 (IEEE, 2006), pp. 1–5. [CrossRef]
  11. H. Wu, N. Narendran, Y. Gu, and A. Bierman, “Improving the performance of mixed-color white LED systems by using scattered photon extraction technique,” Proc. SPIE 6669, 666905 (2007). [CrossRef]
  12. M. O. Holcomb, R. Mueller-Mach, G. O. Mueller, D. Collins, R. M. Fletcher, D. A. Steigerwald, S. Eberle, Y. K. Lim, P. S. Martin, and M. Krames, “The LED lightbulb: are we there yet? Progress and challenges for solid state illumination,” Conference on Lasers and Electro-Optics Quantum Electronics and Laser Science Conference, Technical Digest (Optical Society of America, 2003), paper CMQ2.
  13. A. Zukauskas, R. Vaicekauskas, F. Ivanauskas, R. Gaska, and M. S. Shur, “Optimization of white polychromatic semiconductor lamps,” Appl. Phys. Lett. 80, 234–237 (2002). [CrossRef]
  14. M. Dyble, N. Narendran, A. Bierman, and T. Klein, “Impact of dimming white LEDs: chromaticity shifts due to different dimming methods,” Proc. SPIE 5941, 291–299 (2005).
  15. X. Qu, S. C. Wong, and C. K. Tse, “Color control system for RGB LED light sources using junction temperature measurement,” The 33rd Annual Conference of the IEEE Industrial Electronics Society, IECON 2007, Taipei, Taiwan (IEEE, 2007). [CrossRef]
  16. M. J. Box, “A new method of constrained optimization and a comparison with other methods,” Comput. J. 8, 42–45 (1965).
  17. G. V. Reklaitis, R. Ravindran, and K. M. Ragsdell, Engineering Optimization-Methods and Applications (Wiley, 1983).

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