TY - JOUR
T1 - Selective Coating of White Silicone to Improve the Optical and Thermal Characteristics of White LED Packages
AU - Kim, Ho Young
AU - Kim, Hyoung Jin
AU - Lee, Jong Woo
AU - Kang, Kyoung Mo
AU - Oh, Jeong Tak
AU - Jeong, Hwan Hee
AU - Seong, Tae Yeon
PY - 2020/1/8
Y1 - 2020/1/8
N2 - We investigated the effect of selective coating of white silicone on the output and thermal performance of white LED packages for middle power lighting application. The LED package, where a Zener diode part was coated by TiO2 particles-mixed white silicone, exhibited lower surface temperature and heat flux than those with the uncoated Zener diode. The white silicone-coated packages resulted in lower thermal resistance (Rth) than the uncoated ones. For example, the Rth at 85 °C of the uncoated and coated white LED packages in the junction-PCB was 26.30 K W-1 and 21.98 K W-1, respectively. The coated blue and white LED packages yielded 6.5% and 4.5% higher luminous fluxes than the uncoated packages, respectively. Far-field emission patterns showed that the coated white LED packages had view angle of 118.06° and 118.10° along the two orthogonal directions, respectively, whilst the uncoated package gave 117.37° and 117.55°. After operation under 60 °C/80% relative humidity condition for 1000 h, the uncoated white LED package yielded maintenance rate of 96.85% whereas the coated packages gave 98.17%. At 85 °C under 200 mA, the thermal resistance of the white silicone-coated white LED packages was lowered by 17.7% than the uncoated packages.
AB - We investigated the effect of selective coating of white silicone on the output and thermal performance of white LED packages for middle power lighting application. The LED package, where a Zener diode part was coated by TiO2 particles-mixed white silicone, exhibited lower surface temperature and heat flux than those with the uncoated Zener diode. The white silicone-coated packages resulted in lower thermal resistance (Rth) than the uncoated ones. For example, the Rth at 85 °C of the uncoated and coated white LED packages in the junction-PCB was 26.30 K W-1 and 21.98 K W-1, respectively. The coated blue and white LED packages yielded 6.5% and 4.5% higher luminous fluxes than the uncoated packages, respectively. Far-field emission patterns showed that the coated white LED packages had view angle of 118.06° and 118.10° along the two orthogonal directions, respectively, whilst the uncoated package gave 117.37° and 117.55°. After operation under 60 °C/80% relative humidity condition for 1000 h, the uncoated white LED package yielded maintenance rate of 96.85% whereas the coated packages gave 98.17%. At 85 °C under 200 mA, the thermal resistance of the white silicone-coated white LED packages was lowered by 17.7% than the uncoated packages.
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U2 - 10.1149/2162-8777/aba562
DO - 10.1149/2162-8777/aba562
M3 - Article
AN - SCOPUS:85088901085
SN - 2162-8769
VL - 9
JO - ECS Journal of Solid State Science and Technology
JF - ECS Journal of Solid State Science and Technology
IS - 6
M1 - 065008
ER -