3-D Without Glasses
A new kind of ­display can deliver 3-D images directly to multiple users

Source: "Backlight for View-Sequential Autostereo 3D"
Adrian Travis et al.
Society for Information Display 2010 Digest, 215-217

Results: Researchers at Microsoft created a thin TV display that can show a 3-D image simultaneously to two viewers, who don't need to wear special glasses. The display can also send each of the viewers a different image.

Why it matters: Researchers and companies have been trying to develop 3-D displays that are more realistic, comfortable, and practical than the current technologies, most of which require cumbersome or expensive eyewear. Better ways to deliver 3-D images could lead to new consumer devices and more realistic teleconferencing.

Methods: The Microsoft researchers simplified an existing method of directing light to a particular viewer. The display is made of a plastic wedge with a liquid-­crystal display screen in front of it. A camera on top of the display tracks each viewer's gaze. Depending on where the viewer is looking, 30 light-emitting diodes in a row along the bottom of the display switch on and off to direct light into the wedge, which in turn directs it out of the LCD screen and toward a particular eye. The system can quickly send out light signals representing as many as four images. The images arriving at each of a viewer's eyes differ slightly, making the video appear three-­dimensional.

Next steps: The group is looking at other ways to use the display. If integrated into the backlight of a laptop screen, it could provide a way to toggle instantly between a private view, in which the backlight steers the images toward a single person's eyes, and a shared view, in which the images shine out in all directions.