CRT versus LCD: effects of refresh rate, display technology and background luminance in visual performance

Abstract

Two experiments were carried out in this study. The first experiment assessed a subject's performance while carrying out a visual search task using a liquid crystal display (LCD) and a cathode ray tube (CRT) with varying refresh rate (48–75 Hz). The subject's task consisted of detecting a target character among distractor characters presented in positive contrast. Search time was similar in all conditions of the experiment. Error frequency was correlated positively with the refresh rate of the CRT. However, this effect failed to be significant ( p=0.090). In the condition where LCD was used, error frequency was found to be 22% lower when compared to the condition where the CRT was used with a refresh rate of 75 Hz. A second experiment aimed to assess the role of background luminance in the same task as reported above. The task was carried out on the liquid crystal LCD. The background luminance was varied between 45 and 150 cd/m 2 at the LCD and between 45 and 110 cd/m 2 at the CRT. Results of this experiment revealed no statistical significant effect of background luminance on visual performance (number of hits, search time). These findings suggest that replacing CRTs with LCDs will improve ergonomics in workplaces using visual displays. Improvements can also be achieved by increasing the refresh rate of the CRT but a very high refresh rate may be required.