3-D crystal exhibiting multiple 2-D images with directivity

Unlike conventional 2-D displays, volumetric displays have depth information and enable the 3-D images to be observed from any surrounding viewpoint. In a previous study, we developed an algorithm for utilizing the 3-D architecture of volumetric displays [Nakayama et al. 2013]. The 3-D objects designed by the algorithm can exhibit multiple 2-D images towards different directions simultaneously. Figure 2a shows a prototype of a 3-D crystal which has been designed using the proposed algorithm. As shown in Figure 2b, we can recognize three images when we look at it from the respective directions. In other words, the 3-D crystal is independently providing three images with directivity.