Physical-based Photon Mapping Technique for LED Back-light Lighting Simulator

With the increasing popularity of LCD displays due to lower prices and larger sizes, backlights with an RGB LED source are slowly replacing CCFL-type backlights, as an RGB LED has a wider color gamut, higher luminance, and lower power consumption. However, even though light modules with an array of individual LEDs can uniformly cover the entire backlight area, this does not ensure chromaticity and luminance uniformity over the backlight panel, thereby stressing the need for a lighting simulation of the backlight. Accordingly, this paper proposes an effective lighting simulator that is able to predict the chromaticity and luminance distribution of an LCD backlight panel, especially an LED-type backlight. A photon mapping technique based on Monte Carlo ray tracing is utilized for tracing photons and visualization of the photon map. Plus, for a more accurate prediction, along with the spectral characteristics of the LED source and panel sheets, the more complex optical characteristics depending on the wavelength and incident angle of the photon are also modeled.