Measurement of multiple JNDs for developing Mura ranking standards in LCD

This study aims to measure the multiple visual contrast thresholds on the Mura (a kind of drawback on LCD panels) defects by eyes, so that a common Mura ranking standard was set up from the multiple JNDs to reduce the conflict between the LCD manufacturers and customers. In this experiment, six typical Mura types, negative spacer, positive spacer, line, v-band, light leakage, and curtain were tested, and 25 subjects reported whether the test and the reference patterns were the same or not. From the experimental results, the fitting functions of multiple JNDs for different Mura types were obtained, which were the non-linear curves. Furthermore, the Mura ranking standard system was proposed by finding out the fittest non-linear transformed function, and from which, any Mura defect was assigned to the corresponding Mura rank according to the counted JND value.

► The contrast sensitivity on human visual performance was found a non-linear function. ► The non-linear JND was found to set up the standard of Mura rank in the vision model. ► The Mura ranking standards system plays a common platform for LCD manufacturers and customers. ► This study demonstrated that the human visual sensitivities among six Mura types were different.