Coming Soon: Glasses-Free 3-D Movie Theaters

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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.

via OpticsInfoBase, Optical Society