Improved angle‐of‐view measurement method for display devices

With the increasing demand for a better FPD image quality, better evaluation metrics and advanced display quality meas- urement methods are required to meet these needs. There are many measurement methods for evaluating the viewing angle of various display devices, but these methods, which include luminance drop, color shift, and contrast ratio decrease, are imperfect considering that human perception does not completely correlate to them. In this paper, a new method of measuring the percep- tual angle of FPDs is proposed, considering human visual perception, which uses the color space of the color appearance model. The display industry is currently characterized by in- tense competition. A greater variety of display devices are available from an increasing number of display makers, resulting in the efforts of companies to try to outsurvive one another. To satisfy their customers, companies are develop- ing new technologies for image quality improvement and cost reduction. In this challenging situation, the use of spe- cifications that best represent the display performance has become an important factor when buying TVs and monitors. The viewing angle is one such specification. LCD displays, which are now regarded as the most popular display type, are considered to have a wide viewing angle if their angle of view is 170° or more. The angle of view of LCDs is measured at the point when the contrast ratio drops to 10:1. This criterion, however, is actually a legacy specification as the current-day consumers would not consider a contrast ratio of only over 10:1 acceptable. Therefore, appropriate new criteria for evaluating angle-dependent quality are re- quired. The recently proposed methods consider the change in the contrast ratio, luminance, and color. In this paper, a method is proposed involving the comparison of the percep- tual angles based on the change in brightness and colorful- ness.