Improvement of lumen efficiency in white light-emitting diodes with air-gap embedded package

In this paper, white light-emitting diodes (LEDs) with air-gap embedded package were proposed and fabricated by a simple method including pulsed spray coating. The lumen efficiency of air-gap embedded LED was enhanced by 8.8% at driving current of 350mA, compared to conventional remote phosphor whit...

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Bibliographic Details
Published in:Microelectronics and reliability 2012-05, Vol.52 (5), p.933-936
Main Authors: Chen, H.C., Chen, K.J., Lin, C.C., Wang, C.H., Yeh, C.C., Tsai, H.H., Shih, M.H., Kuo, H.C.
Format: Article
Language:English
Subjects:
Computing time
Electric fields
Light-emitting diodes
Lumens
Monte Carlo methods
Packages
Phosphors
Utilization
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Summary:In this paper, white light-emitting diodes (LEDs) with air-gap embedded package were proposed and fabricated by a simple method including pulsed spray coating. The lumen efficiency of air-gap embedded LED was enhanced by 8.8% at driving current of 350mA, compared to conventional remote phosphor white LED. This improvement was due to the enhanced utilization of blue and yellow rays, which were confirmed by pulse current-dependent correlated color temperature (CCT). The utilization efficiency of blue rays was enhanced by 12.4% due to the embedded air-gap layer. The simulation results performed by Monte-Carlo ray tracing method agreed with our experiments, which showed enhancement in lumen efficiency and similar CCT. Finally, the electric field intensity versus different thickness for air-gap and no air-gap embedded white LED was calculated to check the incident blue rays trapped in phosphor layer.
ISSN:0026-2714
1872-941X
DOI:10.1016/j.microrel.2012.02.011