Title: Efficiency and Droop Improvement in Hybrid Warm White LEDs Using InGaN and AlGaInP High-Voltage LEDs
Authors: Chen, Kuo-Ju
Kuo, Hsuan-Ting
Chiang, Yen-Chih
Chen, Hsin-Chu
Wang, Chao-Hsun
Shih, Min-Hsiung
Lin, Chien-Chung
Pan, Ching-Jen
Kuo, Hao-Chung
Department of Photonics
Keywords: High voltage;light-emitting diodes (LEDs);phosphor;warm white
Issue Date: 1-Apr-2013
Abstract: This study investigates the optical and electrical characteristics in hybrid warm white high-voltage light-emitting diodes (HV-LEDs). The luminous efficiency of the hybrid warm white LED in this study improved by 11% and 51%, compared to conventional cool and warm LEDs, respectively, solving the warm white gap in white LEDs. The efficiency droop of the hybrid warm white LED was reduced to 21.8% from 26.8% for the conventional cool white LED, and from 26.3% in the conventional warm white LED at 40 mA (35 A/cm(2)) the operated current. Furthermore, the color rendering index (CRI) and angular correlated color temperature (CCT) were analyzed, indicating a significant improvement in hybrid warm white HV-LEDs.
URI: http://dx.doi.org/10.1109/JDT.2012.2227054
ISSN: 1551-319X
DOI: 10.1109/JDT.2012.2227054
Volume: 9
Issue: 4
Begin Page: 280
End Page: 284
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