A low-cost method for minimizing the chromaticity shift of dc-driven phosphor-converted white LEDs by thermal design

Ka Hong Loo; Y. M. Lai; Chi Kong Tse

doi:10.1109/ICPE.2011.5944595

A low-cost method for minimizing the chromaticity shift of dc-driven phosphor-converted white LEDs by thermal design

Ka Hong Loo, Y. M. Lai, Chi Kong Tse

The Hong Kong Polytechnic University

Research output: Chapter in book / Conference proceeding › Conference article published in proceeding or book › Academic research › peer-review

4 Citations (Scopus)

Abstract

Most commercial white LEDs are made from blue LEDs coated with YAG phosphor. They generally produce emission spectra that shift in opposite directions under the influences of current amplitude and junction temperature changes. By using a commercial white LED sample, LUXEON K2, the effects of current amplitude and junction temperature on the chromaticity shift of white LEDs over dimming, during which both parameters are known to assert their influences simultaneously, are studied experimentally. The impact of driving/dimming by dc current is discussed through a graphical analysis and verified by experimental measurement. Due to the counteracting influences of current amplitude and junction temperature changes, driving/dimming white LEDs by dc current offers a more superior chromaticity stability compared to PWM. By means of selection of a heat sink's thermal resistance estimated from an analytical equation derived in this paper, it is found that the overall chromaticity shift of white LEDs over dimming can be minimized at low cost.

Original language	English
Title of host publication	8th International Conference on Power Electronics - ECCE Asia
Subtitle of host publication	"Green World with Power Electronics", ICPE 2011-ECCE Asia
Pages	515-519
Number of pages	5
DOIs	https://doi.org/10.1109/ICPE.2011.5944595
Publication status	Published - 31 Aug 2011
Event	8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia - Jeju, Korea, Republic of Duration: 30 May 2011 → 3 Jun 2011

Conference

Conference	8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia
Country/Territory	Korea, Republic of
City	Jeju
Period	30/05/11 → 3/06/11

Keywords

AM driving
chromaticity shift
color stability
thermal design
White LED

ASJC Scopus subject areas

Electrical and Electronic Engineering

More information

10.1109/ICPE.2011.5944595

Cite this

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title = "A low-cost method for minimizing the chromaticity shift of dc-driven phosphor-converted white LEDs by thermal design",

abstract = "Most commercial white LEDs are made from blue LEDs coated with YAG phosphor. They generally produce emission spectra that shift in opposite directions under the influences of current amplitude and junction temperature changes. By using a commercial white LED sample, LUXEON K2, the effects of current amplitude and junction temperature on the chromaticity shift of white LEDs over dimming, during which both parameters are known to assert their influences simultaneously, are studied experimentally. The impact of driving/dimming by dc current is discussed through a graphical analysis and verified by experimental measurement. Due to the counteracting influences of current amplitude and junction temperature changes, driving/dimming white LEDs by dc current offers a more superior chromaticity stability compared to PWM. By means of selection of a heat sink's thermal resistance estimated from an analytical equation derived in this paper, it is found that the overall chromaticity shift of white LEDs over dimming can be minimized at low cost.",

keywords = "AM driving, chromaticity shift, color stability, thermal design, White LED",

author = "Loo, {Ka Hong} and Lai, {Y. M.} and Tse, {Chi Kong}",

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booktitle = "8th International Conference on Power Electronics - ECCE Asia",

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Loo, KH, Lai, YM & Tse, CK 2011, A low-cost method for minimizing the chromaticity shift of dc-driven phosphor-converted white LEDs by thermal design. in 8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia., 5944595, pp. 515-519, 8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia, Jeju, Korea, Republic of, 30/05/11. https://doi.org/10.1109/ICPE.2011.5944595

A low-cost method for minimizing the chromaticity shift of dc-driven phosphor-converted white LEDs by thermal design. / Loo, Ka Hong; Lai, Y. M.; Tse, Chi Kong.
8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia. 2011. p. 515-519 5944595.

Research output: Chapter in book / Conference proceeding › Conference article published in proceeding or book › Academic research › peer-review

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AU - Tse, Chi Kong

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Y1 - 2011/8/31

N2 - Most commercial white LEDs are made from blue LEDs coated with YAG phosphor. They generally produce emission spectra that shift in opposite directions under the influences of current amplitude and junction temperature changes. By using a commercial white LED sample, LUXEON K2, the effects of current amplitude and junction temperature on the chromaticity shift of white LEDs over dimming, during which both parameters are known to assert their influences simultaneously, are studied experimentally. The impact of driving/dimming by dc current is discussed through a graphical analysis and verified by experimental measurement. Due to the counteracting influences of current amplitude and junction temperature changes, driving/dimming white LEDs by dc current offers a more superior chromaticity stability compared to PWM. By means of selection of a heat sink's thermal resistance estimated from an analytical equation derived in this paper, it is found that the overall chromaticity shift of white LEDs over dimming can be minimized at low cost.

AB - Most commercial white LEDs are made from blue LEDs coated with YAG phosphor. They generally produce emission spectra that shift in opposite directions under the influences of current amplitude and junction temperature changes. By using a commercial white LED sample, LUXEON K2, the effects of current amplitude and junction temperature on the chromaticity shift of white LEDs over dimming, during which both parameters are known to assert their influences simultaneously, are studied experimentally. The impact of driving/dimming by dc current is discussed through a graphical analysis and verified by experimental measurement. Due to the counteracting influences of current amplitude and junction temperature changes, driving/dimming white LEDs by dc current offers a more superior chromaticity stability compared to PWM. By means of selection of a heat sink's thermal resistance estimated from an analytical equation derived in this paper, it is found that the overall chromaticity shift of white LEDs over dimming can be minimized at low cost.

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KW - thermal design

KW - White LED

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A low-cost method for minimizing the chromaticity shift of dc-driven phosphor-converted white LEDs by thermal design

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ASJC Scopus subject areas

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