Glasses-Free 3-D Movie Theaters Coming Soon

In South Korea, a team of investigators thinks they have a way to show 3-D movies without glasses in commercial theaters.
3-D televisions are available now, and consumer electronics companies have  been showing off some glasses-free technologies (as on the Nintendo  3DS). But generally, theaters use a two-projector polarized light  system.

 

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Each projector displays an image, but the images are offset slightly. The  projectors, meanwhile, are sending out light that is polarized. That  means that at certain angles half the light is absorbed.

It's possible  to see this effect with sunglasses; two polarized lenses. Put one in  front of the other and start rotating it, and it's not possible to see  through them when one is perpendicular to the other. In movie theaters,  the 3-D glasses are polarized so that each eye only picks up one image  at a time, giving the illusion of depth. Two projectors, though, can be  cumbersome and expensive.
There are single projection methods, but those require even more moving  parts, involving physical barriers akin to venetian blinds between the  screen and the viewer. Called the parallax barrier method, the barriers  limit which image the eye sees, creating a 3-D illusion.
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To fix this, the South Korean team, led by Byoungho Lee, professor at the  School of Electrical Engineering at Seoul National University, used  polarizers to stop the passage of light after it reflects off the screen rather than doing so at the projector.

The polarizer is a coating  called called quarter-wave retarding film. It acts like the polarizers  in two-projector systems, except instead of relying on two images, it  splits up the single one coming off the screen to the eye. Basically, it moves the 3-D glasses to the screen, so the audience no longer has to  wear them.
It will be a while before theaters use this, but it's been shown to work  in at least two types of displays, and offers a path to cutting the  costs (and the admission prices) of 3D movies.