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Proceedings Paper

Modelling the spatial colour distribution of phosphor-white high power light-emitting diodes
Author(s): A. Keppens; S. Denijs; S. Wouters; W. R. Ryckaert; G. Deconinck; P. Hanselaer
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Paper Abstract

In contrast to the spatial (luminous) intensity distribution of high power light-emitting diodes (LEDs), little effort has been made to examine the spatial colour distribution of these light sources, i.e. the values of CIE colour coordinates as a function of direction in space. The spatial colour variation is negligible for single colour emitters, but this is not the case for bichromatic white LEDs using phosphor for wavelength conversion. As the latter diode types are most often used for high colour rendering applications, a quantitative description of their colour distribution is necessary. Therefore, photogoniometer measurements have been performed on a variety of white light-emitting diodes incorporating a planar (remote) phosphor. In this paper measurement results are used to discuss and model the spatial colour distribution of phosphor-white LEDs. Such LEDs appear to show an intrinsic and inevitable spatial colour variation. Furthermore, the measurement data and constructed model allow evaluating the visibility of spatial colour differences and the relevance of colour binning measurements at the end of LED package production lines. Using insights on spatial colour distribution gathered throughout this paper, a design proposal is made to vastly decrease the colour variation of phosphor-white LEDs.

Paper Details

Date Published: 14 May 2010
PDF: 10 pages
Proc. SPIE 7717, Optical Modelling and Design, 77170J (14 May 2010); doi: 10.1117/12.853016
Show Author Affiliations
A. Keppens, Catholic Univ. College Gent (Belgium)
Katholieke Univ. Leuven (Belgium)
S. Denijs, Catholic Univ. College Gent (Belgium)
S. Wouters, Catholic Univ. College Gent (Belgium)
W. R. Ryckaert, Catholic Univ. College Gent (Belgium)
Katholieke Univ. Leuven (Belgium)
G. Deconinck, Katholieke Univ. Leuven (Belgium)
P. Hanselaer, Catholic Univ. College Gent (Belgium)
Katholieke Univ. Leuven (Belgium)


Published in SPIE Proceedings Vol. 7717:
Optical Modelling and Design
Frank Wyrowski; John T. Sheridan; Jani Tervo; Youri Meuret, Editor(s)

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