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Thermal Analyses of LED Light Bars and Backlight Modules

  • M.-Y. Tsai (a1), C.-Y. Tang (a1), C.-E. Zheng (a1), Y.-Y. Tsai (a2) and C.-H. Chen (a2)...

Abstract

The effects of various parameters, such as thermal properties of substrates, thermal interface materials (TIMs) and heat sinks on the thermal performance of the light emitting diode (LED) light bars and backlight module are investigated experimentally and numerically in terms of junction temperature (Tj ) and thermal resistances from junction to air (Rj-a ). The results show that the measured Rj-a of the light bars by powering-on five LEDs in the test is different from one by powering-on only one LED, resulting from the extra heat coming from the adjacent LED packages affecting the Tj for the case of powering-on five LEDs. For the modules, Rj-a is significantly reduced by using the heat sinks for all backlight modules, and aluminum and iron heat sinks do not show any obvious difference in heat dissipation along with any substrates and TIMs. Furthermore, both experimental and simulation results show that the thermal conductivity of the substrates are more important and dominant than TIM and heat sink for the Rj-a of the backlight modules concerned, and also demonstrate that the thermal field for the local model can represent the one in full-scale backlight module.

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*Corresponding author (mytsai@mail.cgu.edu.tw)

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