A method for evaluating luminance non-uniformity of displays by use of a commercially available digital camera

Abstract

The luminance uniformity of liquid-crystal displays (LCDs) deteriorates with their prolonged use. In this paper, we present a method for evaluating the degree of luminance non-uniformity of LCDs with the use of a commercially available digital camera. In this study, seven monochrome LCDs, which were used during various operating times ranging from 5000 to 25,000 h, were evaluated with use of a camera. The maximum luminance deviation (MLD) was measured on the two-dimensional (2D) images obtained with the camera. In addition, an index of the luminance non-uniformity was calculated as the ratio of the area exhibiting luminance non-uniformity to the area of the entire LCD screen. We determined the area with the luminance non-uniformity by setting the allowable luminance deviation as the judgment criterion to evaluate the degree of luminance non-uniformity. The MLD values were less than 20% for all conditions, and they varied depending on the locations of the luminance measurement. The area ratios of the luminance non-uniformity based on 2D luminance distributions tended to increase with the duration of use of LCDs, and they indicated the degree of luminance non-uniformity of the LCDs regardless of the measurement locations. Our approach of using a commercially available digital camera showed its potential usefulness for providing more detailed and consistent evaluations of the degree of luminance non-uniformity of LCDs based on the 2D luminance distributions.

Impact of 222 Nm Uv-C Radiation on Color Accuracy of Video Displays in Public Buses

“…Another important aspect is how to evaluate and optimise display performance. Authors have investigated factors that may affect the performance of these displays, including luminance inhomogeneity, viewing angle, resolution, magnification, and window settings (Kawamoto et al, 2017). Others (Hatanaka et al, 2009) have investigated the effect of viewing angle on observer performance and compared the performance of different types of displays.…”