CSD-a new unified threshold metric of evaluating LCD viewing angle by color saturation degradation

Lower luminance contrast ratio and chromatic changes affect the visual performance (i.e. color shift) of a thin-film transistor liquid-crystal device (TFT-LCD) at large viewing angles. The de facto method of defining viewing angle, contrast ratio of luminance, fails to represent the substantial visual performance viewed at a larger angle. We found the degradation of color saturation, dS*/dthetas, to be an appropriate metric to aid the conventional viewing angle definition (CR ges 10). We empirically determined the threshold for defining the color viewing angles of TFT-LCDs, CVA = {thetaspardS*/dthetas| les 0.03}, which reflects the variation not only in chromaticity but also in luminance. The proposed metric was evaluated by psychophysical experiments, whose results validate the efficacy of the proposed metric