Proc. SPIE. 7690, Three-Dimensional Imaging, Visualization, and Display 2010 and Display Technologies and Applications for Defense, Security, and Avionics IV
KEYWORDS: Light emitting diodes, Modulation, Visualization, Liquid crystal on silicon, Projection systems, Digital micromirror devices, 3D displays, LED displays, 3D visualizations, 3D image processing
LED-based projection systems have several interesting features: extended color-gamut, long lifetime, robustness
and a fast turn-on time. However, the possibility to develop compact projectors remains the most important
driving force to investigate LED projection. This is related to the limited light output of LED projectors
that is a consequence of the relative low luminance of LEDs, compared to high intensity discharge lamps. We
have investigated several LED projection architectures for the development of new 3D visualization displays.
Polarization-based stereoscopic projection displays are often implemented using two identical projectors with
passive polarizers at the output of their projection lens. We have designed and built a prototype of a stereoscopic
projection system that incorporates the functionality of both projectors. The system uses high-resolution liquidcrystal-
on-silicon light valves and an illumination system with LEDs. The possibility to add an extra LED
illumination channel was also investigated for this optical configuration. Multiview projection displays allow the
visualization of 3D images for multiple viewers without the need to wear special eyeglasses. Systems with large
number of viewing zones have already been demonstrated. Such systems often use multiple projection engines.
We have investigated a projection architecture that uses only one digital micromirror device and a LED-based
illumination system to create multiple viewing zones. The system is based on the time-sequential modulation
of the different images for each viewing zone and a special projection screen with micro-optical features. We
analyzed the limitations of a LED-based illumination for the investigated stereoscopic and multiview projection
systems and discuss the potential of a laser-based illumination.