Swept-volume display

A swept-volume display is a volumetric display in which the three-dimensional image is formed by illuminating a rapidly moving display surface, which may be "macroscopically" physical (e.g., a spinning diffuser) or otherwise (e.g. exciting a surface of doped ions into a metastable state prior to radiative activation by a second beam). Typical schemes use a circular screen rotating at about 900 rpm, which sweeps a spherical volume at each half-rotation, hence the technology's name. Three-dimensional imagery is perceived due to persistence of vision, in that a collection of voxels is projected at different locations within the volume over a time period such as 1/30 sec; they are visually integrated into one reconstructed 3-D scene.