Evaluating heat dissipation in edge-lit LED backlight module using Taguchi method

Flat panel displays (FPD) are becoming thinner and lighter, and edge-lit backlight modules are gradually replacing direct-lit devices. The number of LEDs is being reduced and high-power LEDs are increasingly being used for illumination. The effectiveness of free convection in the dissipation of heat generated from LEDs is limited in such constricted spaces, resulting in a loss of luminosity and a reduction in the lifespan of the LED devices. In this study, the experimental measurement and simulation of the 8-Watt edge-lit LED backlight module with 40 LEDs in 740 mm* 425 mm* 12 mm size was conducted. This study investigated heat dissipation using ANSYS simulation software, the results of which were in agreement with the experimental data, with a difference of only 1.6°C in the maximum temperature. The edge-lit LED backlight module with heat dissipation mechanism was estimated by using the proposed model. The result demonstrated that the maximum temperature of the heat sink with fins was lower 3°C than without fins. A design of heat sink with fins is contributed to reducing LED temperature. In addition, Taguchi method was introduced for seeking the optimal configurations of heat sink by using the proposed model. In the study, 4 control factors with 2 degree levels, (A) heat transfer pattern on heat sink surface, (B) the thickness of heat sink, (C) the width of heat sink and (D) fin area, were considered. The results indicated that heat sink area with 2.4 mm thick and 60 mm wide, and heat sink with a fin area of 16682 mm2 provided optimal heat dissipation efficiency under the given convection conditions. This study provides an effective approach with which to evaluate thermal management in edge-lit LED backlight modules, thereby reducing the time required for development.