Effects of Saccade Length and Target Luminance on the Refresh Frequency Threshold for the Visibility of Color Break-Up

Field-sequential color displays are susceptible to a visual artefact called color break-up, which is an image-quality problem and may also cause visual discomfort. However, the effect can be greatly reduced by increasing the refresh frequency of the display. In this study, we measured refresh frequency thresholds for color break-up visibility by using a two-alternative forced choice staircase method. Subjects made controlled horizontal saccades so that the gaze followed a white target which abruptly changed position. The white target was a red, green, and blue (RGB) light-emitting diode (LED), in which the red, green, and blue colors were shown sequentially. Saccade length (2, 4, 8, and 14 deg) and target luminance level (2, 31.5, and 500 cd/m) were varied. The contrast between stimulus and background and the size of the stimulus were held constant. The results showed that a refresh frequency as high as 1200 Hz would be needed to completely eliminate the phenomenon. Further, the threshold value increased with saccade length and target luminance. However, the effect of luminance saturated relatively early.