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Optics Letters

Optics Letters


  • Editor: Alan E. Willner
  • Vol. 34, Iss. 1 — Jan. 1, 2009
  • pp: 1–3

Effect of phosphor geometry on the luminous efficiency of high-power white light-emitting diodes with excellent color rendering property

Yu-Ho Won, Ho Seong Jang, Kyoung Woo Cho, Yong Seon Song, Duk Young Jeon, and Ho Ki Kwon  »View Author Affiliations

Optics Letters, Vol. 34, Issue 1, pp. 1-3 (2009)

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High-power white light-emitting diodes (LEDs) are fabricated by combining blue LEDs and green ( Ba , Sr ) 2 Si O 4 : Eu 2 + and red Ca Al Si N 3 : Eu 2 + phosphors with varying phosphor geometry. The white LED having separated the phosphor layer by the silicone gel layer between green and red phosphor layers shows superior optical properties. The luminous efficiency ( η L ) is improved by a decrease of reabsorption of green light by red phosphor owing to a difference among refractive indices. The white LED shows very high η L of 51 lm W and a high color rendering index of 95 under 350 mA . In addition, improved luminous properties of the white LED including a separated phosphor layer are confirmed via ray-trace simulation.

© 2008 Optical Society of America

OCIS Codes
(160.2540) Materials : Fluorescent and luminescent materials
(160.5690) Materials : Rare-earth-doped materials
(230.3670) Optical devices : Light-emitting diodes

ToC Category:

Original Manuscript: August 20, 2008
Revised Manuscript: November 2, 2008
Manuscript Accepted: November 10, 2008
Published: December 19, 2008

Yu-Ho Won, Ho Seong Jang, Kyoung Woo Cho, Yong Seon Song, Duk Young Jeon, and Ho Ki Kwon, "Effect of phosphor geometry on the luminous efficiency of high-power white light-emitting diodes with excellent color rendering property," Opt. Lett. 34, 1-3 (2009)

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