Laser-Based 3-D Volumetric Display System (The Improved Second Generation).

ABSTRACT  NR aD, the RDT&E Division of the Naval Command, Control and Ocean Surveillance Center (NCCOSC), has developed its second generation device for displaying data, information and scenes in a three-dimensional volume of image space. The device incorporates a 36-inch diameter double helix that spins at approximately 10 revolutions per second, providing a means to address a cylindrical volume. Under computer control, a laser beam is directed to illuminate certain discrete volume points (voxels) on the helix needed to create a scene. The laser light scatters from the surface of the helix, so, to the observer, each voxel appears to emanate from specific points in space. Each point has x-y coordinates determined by the position of the laser beam, and a z coordinate determined by the height of the point on the helical surface. Any point within the cylindrical image volume can be computer-addressed to appropriately synchronize the laser eam, the Acousto-Optic (AO) Scanner and the phase of the helix, as shown in figures 1 and 8. Using a novel Acousto-Optic (AO) Random-Access Scanner, up to 40 thousand laser-generated voxels refreshed at 20 Hz per color are projected onto the reflective surface of the rotating helix. (This is about 10 times more than the current state of the art.) The higher resolution allows improved color images, updated in real time, for group viewing with the naked eye (see the optical head in figure 8).