Three-dimensional color display by projection-type composite holography

A new method of projection-type composite holography for displaying three-dimensional (3-D) color information has been developed. The basic concept and the results of the experiments are described. A model 3-D color display system for storing several kinds of colored cinematic information is presented as a practical application of the method. This method constructs the 3-D color image by synthesizing the reconstructed images which are projected on the unilaterally direction-selective screen from several holograms. The 3-D color information is recorded as 3N holograms on a roll film arranged in an arc, the center of which is located on the screen. To reconstruct the 3-D color information three kinds of laser beams (red, green, and blue) illuminate these 3N holograms under the same condition. All the reconstructed images from these 3N holograms are projected and synthesized on the unilaterally direction-selective screen. The direction-selective axis of the screen is set parallel to the direction of the film. Consequently the color components of the reconstructed images are diffusely reflected and the angular components are reflected back in the original direction. The human eye can recognize a 3-D color image in the viewing zone enlarged through the vertical diffusing effect of the screen.