A proposal for a quantitative model of "Mura" level of LCDs on the basis of human senses

The purpose of this study was to quantify the degree of "Mura", which is the luminance non-uniformity of an LCD, from the human-factors point of view. A subjective evaluation was carried out to obtain the JND (just-noticeable-difference) and Distinct levels of Mura. Thirty-one kinds of Mura with circle and rectangle shapes were simulated on a TFT/LCD display for evaluation by subjects. The result indicated that both JND and Distinct levels of Mura is influenced most by the area of Mura. The larger the Mura, the more easily it is detected and becomes annoying. The degree to which is annoying Mura was found to be expressed as a function of area and the contrast of the region of Mura. A new unit, "JND" that indicates the degree to which Mura is annoying, had thus been created; 1.0 JND corresponds to the limit for Mura being noticeable and 3.0 JND is the boundary of the Distinct level. The outcome of this study has already been applied in manufacturing processes and this has been effective.