Effects of Light-Emitting Diode (LED) Configuration on Luminance and Color of an Edge-Lit Backlight Unit

In this paper, we evaluated quantitative changes in the luminance and the color on the light-exit plane of an LED edge-lit backlight unit (BLU) by systematically controlling the optical properties of individual white LEDs. We placed a light absorbing film and red-green-blue filters to control the white intensity and the color of an individual LED string, respectively. Impacts of this `defect' LED's optical properties were systematically monitored across the light-exit plane in terms of local distribution of the luminance and the color, overlaying prism films and diffusion film on a light guiding plate (LGP). The roles of prism films and diffusion film were also experimentally analyzed to assess their homogenizing capability for the luminance and the color with respect to the defect-like LEDs.