Accuracy and repeatability of the ISO 9241-7 test method

Abstract

ISO 9241-7 is the first international specification for quality comparison of anti-glare treatment of CRT-displays. The importance of anti-glare treatment and control of the lighting environment has always been considered important, but there has not been a repeatable and ergonomically validated method available for testing CRTs. The ergonomic validity of the method has been analysed and reported before the standard was approved. However, no research on the metrological quality of the new method has been published. In this paper accuracy and repeatability is defined as the accuracy and international repeatability that can be achieved when the same CRT-display is tested in any competent laboratory. We report research conducted in one laboratory in Europe and report the preliminary results from an interlaboratory comparison testing with two laboratories from Europe and five laboratories from Japan. The focus is on testing two hypotheses. The first hypothesis “the defined test methods are repeatable and reliable” was found to be false, but the problems are small and can be covered by interlaboratory agreement or a future minor update of ISO 9241-7. The second hypothesis “if an integrating sphere is used as light source then it can be used at any distance to the EUT” was true and confirmed the theoretical prediction, which means that one of the limiting requirements on the test set-up, defined in ISO 9241-7, is unnecessary and should be removed from the standard.