Title :
Efficiency and Droop Improvement in Hybrid Warm White LEDs Using InGaN and AlGaInP High-Voltage LEDs
Author :
Kuo-Ju Chen ; Hsuan-Ting Kuo ; Yen-Chih Chiang ; Hsin-Chu Chen ; Chao-Hsun Wang ; Min-Hsiung Shih ; Chien-Chung Lin ; Ching-Jen Pan ; Hao-Chung Kuo
Author_Institution :
Dept. of Photonics, Nat. Chiao Tung Univ., Hsinchu, Taiwan
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/cm2) 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.
Keywords :
III-V semiconductors; LED lamps; aluminium compounds; gallium compounds; indium compounds; wide band gap semiconductors; AlGaInP; InGaN; angular correlated color temperature; color rendering index; droop improvement; efficiency improvement; electrical characteristics; high voltage LED; high voltage light emitting diodes; hybrid warm white LED; optical characteristics; Light emitting diodes; Optical materials; Phosphors; Photonics; Solid state lighting; Vertical cavity surface emitting lasers; High voltage; light-emitting diodes (LEDs); phosphor; warm white;
Journal_Title :
Display Technology, Journal of
DOI :
10.1109/JDT.2012.2227054
