Holographic video display using digital micromirrors (Invited Paper)

We have established that the digital micromirror device (DMD), a component of the Texas Instrument Digital Light Processing system, can be used as a holographic medium by calculating a computer-generated hologram (CGH) and projecting multiple objects at various distances with a single hologram. Like other spatial light modulators (SLM), the DMD has the dynamic capability to display holograms at video rates. Unlike other SLMs, the high reflectivity of the DMD provides the intensity necessary to project a holographic 3D scene. We have characterized many of the properties for utilizing the DMD for holography, including the grating effect of the mirror arrays, resolution, viewing angle, field of view and the number of gray levels that can be displayed by the DMD. Several techniques and algorithms that were investigated to calculate the CGH for vivid display with a DMD are discussed. Prototypes of a holographic real image projection system and a virtual image viewer are being pursued. Since a good, low cost medium for displaying holographic projections does not yet exist, we are developing a volumetric display system consisting of a series of liquid-crystal layers with sequencing electronics. Analysis of image definition, inverted image overlap, and depth of field associated with the current projection system design are also presented. Potential uses of holographic viewing systems are reviewed along with methods for overcoming the challenges of using the DMD for the next generation holographic projection system.