Time multiplexed autostereoscopic displays are often associated with complex optics design and have not yet been made in a flat panel format. The reason is mainly because the high bandwidth image sources are not available as flat panel displays. The optical Wedge developed at Cambridge University compresses the optics into a single flat waveguide, which allows for a flat panel time multiplexed autostereoscopic display. By using an active shutter synchronized with a custom built high frame rate DLP light engine we suggest two approaches for creating a flat panel 3D display. The limitations on size are purely limited by the shutter size. However, we also suggest a solution where a small shutter can be used to create a large sized display.
The authors present work that was conducted as a collaboration between Cambridge University and MIT. The work is a continuation of previous research at Cambridge University, where several view-sequential 3D displays were built. The authors discuss a new display which they built and compare performance to previous versions. The new display utilizes a DMD projection engine, whereas previous versions used high frame rate CRTs to generate imagery. The benefits of this technique are discussed, and suggestions for future improvements are made.
If a three dimensional image is to be projected into mid-air in a room with bare walls, then light must follow a curving path. Since this does not happen in a vacuum, a gradient must be introduced into the refractive index of air itself, which can be introduced by varying either the temperature or pressure of air. A reduction from 300°C to room temperature across the front of a 1 mm wide ray will bend it with a radius of curvature of 3 m. However the temperature gradient cannot be sustained without an unacceptably aggressive mechanism for cooling. The pressure gradients delivered by sound waves are dynamically sustainable, but even powers as extreme as 175 dBm at 25 kHz deliver a radius of curvature of only 63 m. It appears that something will have to be added to the air if such displays are to be possible.