Phosphor converted LEDs with omni-directional-reflector coating.
A packaging scheme utilizing omni-directional reflective (ODR) optical coating is described to enhance the light extraction of near UV excited, phosphor-converted LEDs. A simple 1D model was developed to analyze the spectra of the extracted light measured with an integration-sphere as a function of phosphor layer concentration and thickness. Quantitative determination of the absorption coefficients at the pump and fluorescent light wavelength along with the conversion coefficient of phosphors were obtained. The reflection of the ODR film and the back reflector are also characterized. These parameters are then used for efficiency optimization of the present packaging scheme. A maximum enhancement of 40% can be expected with the materials and the configuration used in the present work.
Chi
Jim-Yong
JY
Institute of Opto-Electronics Engineering, National Dong Hwa University, Hualien, Taiwan 97401, R.O.C. chij@mail.ndhu.edu.tw
Chen
Ji-Siao
JS
Liu
Chuan-Yu
CY
Chu
Cheng-wen
CW
Chiang
Kuo-Hsien
KH
D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D008027:Light; D008029:Lighting / Q000295:instrumentation*; D012542:Scattering, Radiation; D012666:Semiconductors