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Light & Engineering 26 (2)

Light & Engineering 26 (2)

Volume 26
Date of publication 07/01/2018
Pages 81-87

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TM-30–15 and CIE-CRI-Ra: Investigation of Сolour Rendering of White PC LEDs . L&E 26 (2) 2018
Articles authors:
Karin Bieske, Ulla Maria Hartwig , Christoph Schierz, Alexander Wilm, Carolin Horst

Dr.-Ing. She is a research fellow in the lighting enginee ring group of Technische Universitat Ilmenau. Since 1998, she is working there in research and teaching. She graduated in the field of electrical engineering with focus on biomedical engineering and cyber netics, and obtained a doctorate in the field of lighting engineering at Technische Universitat Ilmenau. She is an active in associations and commit tees for lighting, colour and standardisation

obtained her Master Degree in the field of Optical Systems Engineering / Optronics at Technische Universitat Ilmenau. In her master thesis, she investigated the colour rendering pro per ties of LED light sources

Prof. Dr. He is chair of the lighting engineering group at Technische Universitat Ilmenau since 2007. After graduating in physics with focus on optics and atmospheric physics, he conducted research in occupational health. He gained his doctorate with a thesis on the use of light and colour at the work place taking into account physiological parameters of the eye. He is member in the board of several professional societies and is actively involved in the work of standardisation committees like DIN, CEN and CIE

is Senior Key Expert for illumination in the GL application engineering department at OSRAM Opto Semiconductors in Regensburg. He joined OSRAM OS in 2004 after graduating from the University of Applied Sciences in Regensburg with a diploma in Mechatronic Engineering. In his career he started with optics and system design for LED headlamps, flash lights and projectors. After being stationed in Singapore for 2 years, he works as Application Engineer and Key Expert for SSL products and light quality. He is active in several expert associations for general lighting and driving, the innovation in solid state lighting

is applications engineer and expert for General Lighting at OSRAM Opto Semiconductors where she is responsible for the field of light quality. She obtained her Bachelor Degree in the field of Optronics and her Master Degree in the field of Optical Systems Engineering at the Technical University Ilmenau

Abstract
The colour rendering properties of 21 phosphor converted LED light sources (pc LED) with different Rf and Rg values as in the Fidelity Index and Gamut Index of the TM­30–15 have been investigated. Scenarios illuminated by pc LEDs, a fluorescent lamp (FL) and a tungsten halogen lamp (THL) were presented to 34 subjects. An assortment of coloured objects was arranged identically in two adjoining booths and participants rated the test scenarios in comparison with the reference illuminant (THL). For colour quality, both indexes are reflected in the observer’s ratings. The Fidelity Index strongly correlates with the colour difference and colour shift perceived; the Gamut Index with the subjects’ ratings of the colour saturation. Participants found the best match with the fluorescent lamp (Rf = 80/ Rg = 100) to be the pc LEDs with Rf = 75/ Rg = 105 and Rf = 80/ Rg = 105.
References
1. CIE Method of Measuring and Specifying Colour Rendering Properties of Light Sources, CIE13.3, 1995.
2. N. Narendran and L. Deng, “Color Rendering Properties of LED Light Sources”, Proceedings of SPIE, 2002, Vol. 4776, pp. 61–67.
3. Illuminating Engineering Society of North Amerika, IES Method for Evaluating Light Source Color Rendition, 2015, IES TM­30–15.
4. W.A. Thornton, “Colour­discrimination index”, J Opt Soc Am., 1972, Vol. 62, No. 2, pp. 191–194.
5. M. S. Rea, L. Deng and R. Wolsey, “Light Sources and Colour,” NLPIP Lighting Answers (Rensselaer Polytechnic Institute, Troy, NY), Vol. 8, no. 1, October 2004.
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7. M.P. Royer, A. Wilkerson, M. Wei, K. Houser and R. Davis, “Human perceptions of colour rendition vary with average fidelity, average gamut, and gamut shape”, Lighting Res. Technol. 2016, 0: pp. 1–26.
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