Two types of packaged white light emitting diodes in which one has a flat-top (FT) emitting surface and the other is a flat-top-with-lens (FTWL) type are fabricated by using the same leadframe and investigated on their optical properties, such as optical power, luminous efficiency, correlated color temperature (CCT), chromaticity coordinate, and color-rendering index (CRI), as a function of phosphor concentration in silicone encapsulant. It is found out that the optical power, CRI, and CCT decrease steadily as the phosphor ratio increases, while the luminous efficiency increases up to a level and then drops after a certain value of the phosphor ratio for both types of packages. Due to the totally internal reflection (TIR) at the encapsulant-air interface, the FT package shows a power (in mW) reduction compared with the FTWL package at the same phosphor concentration. However, it is demonstrated that the FT package provides a more efficient way of utilizing phosphor than the FTWL package based on the same targeted chromaticity coordinates due to the TIR effect inside, resulting in a reduced phosphor usage with a lumen output only about 3% lower than that of the FTWL package.
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e-mail: grantycl@gmail.com
e-mail: jpyou@uci.edu
e-mail: ntran3000@yahoo.com
e-mail: yzhe2002@hotmail.com
e-mail: fgshi@uci.edu
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March 2011
Research Papers
Packaging of Phosphor Based High Power White LEDs: Effects of Phosphor Concentration and Packaging Configuration
Yuan-Chang Lin,
Yuan-Chang Lin
OptoElectronics Packaging & Materials Lab,
e-mail: grantycl@gmail.com
University of California
, 916 Engineering Tower, Irvine, CA 92697
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Jiun Pyng You,
Jiun Pyng You
OptoElectronics Packaging & Materials Lab,
e-mail: jpyou@uci.edu
University of California
, 916 Engineering Tower, Irvine, CA 92697
Search for other works by this author on:
Nguyen T. Tran,
Nguyen T. Tran
OptoElectronics Packaging & Materials Lab,
e-mail: ntran3000@yahoo.com
University of California
, 916 Engineering Tower, Irvine, CA 92697
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Yongzhi He,
Yongzhi He
OptoElectronics Packaging & Materials Lab,
e-mail: yzhe2002@hotmail.com
University of California
, 916 Engineering Tower, Irvine, CA 92697
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Frank G. Shi
Frank G. Shi
OptoElectronics Packaging & Materials Lab,
e-mail: fgshi@uci.edu
University of California
, 916 Engineering Tower, Irvine, CA 92697
Search for other works by this author on:
Yuan-Chang Lin
OptoElectronics Packaging & Materials Lab,
University of California
, 916 Engineering Tower, Irvine, CA 92697e-mail: grantycl@gmail.com
Jiun Pyng You
OptoElectronics Packaging & Materials Lab,
University of California
, 916 Engineering Tower, Irvine, CA 92697e-mail: jpyou@uci.edu
Nguyen T. Tran
OptoElectronics Packaging & Materials Lab,
University of California
, 916 Engineering Tower, Irvine, CA 92697e-mail: ntran3000@yahoo.com
Yongzhi He
OptoElectronics Packaging & Materials Lab,
University of California
, 916 Engineering Tower, Irvine, CA 92697e-mail: yzhe2002@hotmail.com
Frank G. Shi
OptoElectronics Packaging & Materials Lab,
University of California
, 916 Engineering Tower, Irvine, CA 92697e-mail: fgshi@uci.edu
J. Electron. Packag. Mar 2011, 133(1): 011009 (5 pages)
Published Online: March 10, 2011
Article history
Received:
November 17, 2009
Revised:
November 8, 2010
Online:
March 10, 2011
Published:
March 10, 2011
Citation
Lin, Y., You, J. P., Tran, N. T., He, Y., and Shi, F. G. (March 10, 2011). "Packaging of Phosphor Based High Power White LEDs: Effects of Phosphor Concentration and Packaging Configuration." ASME. J. Electron. Packag. March 2011; 133(1): 011009. https://doi.org/10.1115/1.4003216
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