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Proceedings Paper

Binning and filtering: the six-color solution
Author(s): Ian Ashdown; Shane Robinson; Marc Salsbury
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Paper Abstract

The use of LED backlighting for LCD displays requires careful binning of red, green, and blue LEDs by dominant wavelength to maintain the color gamuts as specified by NTSC, SMPTE, and EBU/ITU standards. This problem also occurs to a lesser extent with RGB and RGBA assemblies for solid-state lighting, where color gamut consistency is required for color-changing luminaires. In this paper, we propose a "six-color solution," based on Grassman's laws, that does not require color binning, but nevertheless guarantees a fixed color gamut that subsumes the color gamuts of carefully-binned RGB assemblies. A further advantage of this solution is that it solves the problem of peak wavelength shifts with varying junction temperatures. The color gamut can thus remain fixed over the full range of LED intensities and ambient temperatures. A related problem occurs with integrated circuit (IC) colorimeters used for optical feedback with LED backlighting and RGB(A) solid-state lighting, wherein it can be difficult to distinguish between peak wavelength shifts and changes in LED intensity. We apply our six-color solution to the design of a novel colorimeter for LEDs that independently measures changes in peak wavelength and intensity. The design is compatible with current manufacturing techniques for tristimulus colorimeter ICs. Together, the six-color solution for LEDs and colorimeters enables less expensive LED backlighting and solid-state lighting systems with improved color stability.

Paper Details

Date Published: 12 September 2006
PDF: 11 pages
Proc. SPIE 6337, Sixth International Conference on Solid State Lighting, 63371A (12 September 2006); doi: 10.1117/12.680823
Show Author Affiliations
Ian Ashdown, TIR Systems Ltd. (Canada)
Shane Robinson, TIR Systems Ltd. (Canada)
Marc Salsbury, TIR Systems Ltd. (Canada)

Published in SPIE Proceedings Vol. 6337:
Sixth International Conference on Solid State Lighting
Ian T. Ferguson; Nadarajah Narendran; Tsunemasa Taguchi; Ian E. Ashdown, Editor(s)

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