An Empirical Comparison of Transparency on One and Two Layer Displays

Two layer displays are constructed by overlaying one transparent flat panel on another, with a discernible physical separation between layers. This layout could increase the available pixels without increasing the width and height of the display. However, it is unclear if the second physical layer provides any advantage over simple alpha-blended transparency on a single layer display. We investigate this issue in two controlled experiments that compare performance between one and two layer displays in users’ perception of two potentially interfering virtual layers of information. Results show that for spatially overlapping stimuli, interference from the background stimuli on the perception of foreground stimuli is similar for both displays, while interference from the foreground stimuli on the perception of the background stimuli is higher with two layer displays. For spatially non-overlapping stimuli, perception is degraded on the two layer display if the distracter object is placed on the front layer.