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41.3: Invited Paper: LED Backlighting Concepts with High Flux LEDs
Author(s) -
Folkerts Wiep
Publication year - 2004
Publication title -
sid symposium digest of technical papers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.351
H-Index - 44
eISSN - 2168-0159
pISSN - 0097-966X
DOI - 10.1889/1.1821339
Subject(s) - backlight , gamut , light emitting diode , rgb color model , brightness , optics , ntsc , liquid crystal display , luminance , transmission (telecommunications) , led lamp , computer science , diode , optoelectronics , physics , computer vision , telecommunications
An overview is presented of three concepts for LCD Backlighting based on high flux, high power LEDs. The trade‐offs for the different concepts for different applications are discussed. Several recent results are presented as well. For the concepts using Red, Green and Blue (RGB) LEDs calculations are presented that address the comparison of RGB LED Backlighting with CCFL Backlighting and quantifies the trade‐off between colour filter (CF) transmission and colour gamut for both types of light source. It is concluded that RGB LED based backlighting gives typically 30% more NTSC coverage for the same CF transmission or alternatively 32–40% higher CF transmission for the same colour gamut. For side‐emitting LEDs calculations are presented that clarify how to optimize uncoupling of the light into a light guide. For the Luxeon‐Direct concept [2] new experimental results are presented for a 23 inch backlight based on two RGB light sources. The results show the dependence of the brightness profile on the spacing between the two light sources and indicate how this design parameter can be used for optimizing the performance in an actual backlight design. For the same concept new results on color uniformity as a function of LED to LED pitch are discussed.