Display Full Text | Download Full Text
4.20 MB PDF file

Degree

PhD, University of Cincinnati, Engineering : Electrical Engineering, 2007.

Abstract

Phosphor-converted light-emitting diode (pcLED) luminaires have been designed and built that address the loss mechanisms present in commercial and literature pcLEDs. Under dc drive conditions, a white pcLED with an organic phosphor achieved 97 lm/W luminous efficacy and a package efficiency of 0.99, a white pcLED with YAG:Ce phosphor achieved 86 lm/W efficacy and a package efficiency of 0.96, and a greenish-yellow pcLED with an organic phosphor achieved 151 lm/W efficacy and a package efficiency of 0.96. The results were obtained with a blue pump LED chip having an efficiency of 0.36. Organic green and red color-conversion materials for use with a blue LED backlight for full-color emissive display applications have been demonstrated. The color converters closely match the NTSC color gamut, have quantum efficiencies exceeding 90%, and are sufficiently stable to withstand a minimum 7,000 hours of operation at 300 cd/m2. A phosphor composite material proposed for future pcLEDs will increase the effective quantum efficiency of the phosphor by eliminating diffuse scattering to allow virtually 100% light extraction. The composite material may also be useful as a gain medium in solid-state lasers and as a fluorescence collector in solar energy applications.

Keywords

phosphor-converted LEDs; solid-state lighting; phosphor composite

Advisor

Dr. Andrew J. Steckl

Pages

119p.

Document number: ucin1186160915
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1186160915

This ETD has been downloaded 1163 times (through March 2013)