The New York Times asks the question: “Which 3D glasses are best?”. The answer to the question is important because Hollywood and theater owners are trying to lure people away from their high definition televisions and back into the theaters. If you control the infant 3-D market for glasses in movie theaters, there is the chance that you can be extremely profitable. There could be an even larger market in the making since 3-D televisions are just coming out.
RealD and Master Image 3D are two companies that make passive circular polarized glasses that cost about 65 cents apiece. It works by having a filter sit in front of the lamp of the projector. This filter oscillates 144 times a second switching the image between clockwise circular polarization (for the right eye) and counter-clockwise circular polarization (for the left eye). The passive glasses have filters so that the right eye has clockwise circular polarization, and the left eye has counter-clockwise circular polarization.
Dolby Laboratories makes passive glasses that cost about $28. The glasses work in conjunction with a special filter wheel installed inside the projector. This filter wheel removes the wavelengths of the light spectrum meant for the left eye only, leaving the right eye to see those wavelengths meant for it. As the wheel spins, it then removes wavelengths of the light spectrum meant for the right eye only, leaving the left eye to see those wavelengths meant for it. The passive glasses have filters so that the right eye only sees its wavelengths, and the left eye its wavelengths.
XpanD uses active LCD shutter glasses to produce a stereo effect. These glasses cost about $50 apiece.
One technology not mentioned in the article is the stereoscopic system used in IMAX 3D, simply Linear Polarization. While linear polarized glasses are cheap, they suffer from usability problems. While circular polarization remains constant as you turn your head (clockwise remains clockwise no matter how far you rotate your head), linear does not. At a 45-degree angle (just lean your head to the right) you see both images with both eyes simultaneously, and just a slight rotation (normal breathing or head-tilt) can be enough to cause the two images to blur and ghost together. Frankly, I’m amazed that IMAX hasn’t upgraded to circular polarization.
Which technology will triumph? Likely it will turn out to be that which gives the movie theaters the highest profit margin. Does it cost more to view circular polarized glasses as disposable, or to try and keep high-cost active shutter glasses in the theater?
Personally, if I was a theater owner, I would buy the 65 cent disposable glasses and charge an extra dollar on the ticket for them, thus making a profit. Since they are plastic, if people left them behind, I would wash them at the end of the day and reuse them.
It is well worth it to read the entire article at the New York Times: A High-Tech Movie Battle: Which 3-D Glasses Are Best?