Analysis on Thermal Management Schemes of LED Backlight Units for Liquid Crystal Displays

Light-emitting diodes (LEDs), have emerged as a new light source for backlight units in novel liquid crystal displays due to their advantages in optical performance and their environmentally friendly features. The characteristics of LEDs, however, are inherently accompanied by high heat dissipation, and performance of an LED device strongly depends on the operating temperature. Therefore, proper thermal management is required to facilitate reliable operation of a backlight unit in a display, and analysis on thermal characteristics of backlight units is imperative for development of reliable thermal management. This paper aims to investigate thermal characteristics of the LED backlight unit according to thermal design parameters. The effects of a thermal management scheme on the maximum temperature of an LED and the temperature uniformity in both edge-light- and direct-light-type LED backlight units are scrutinized. Results demonstrated that the heat dissipation from an LED and the composite conductivity of a thermal scheme play a crucial role on the thermal performance of a unit, and the effect of composite conductivity varies according to the characteristics of a plane where light sources are installed.