In 1954, a few thousand households around the United States—with the equivalent of US $10 000 in today's money to spare—bought the world's first color television sets, from RCA, Westinghouse, and Admiral. Few shows were broadcast in color, and most people wrote it off as an expensive gimmick.
The right eye receives only light waves rotating clockwise, and the left eye gets them counterclockwise.
The liquid-crystal filter in front of the projector lens switches states 144 times per second—letting through only circular clockwise-polarized light, then counterclockwise, then clockwise, and so on. The filter is synced with the projector so that the image for the right eye is projected when the filter lets through clockwise-polarized light; the image for the left eye is projected when the filter lets through counterclockwise-polarized.
2010 is 1954 all over again, but this time with 3-D. Pricey televisions are showing up in only a handful of homes. Movies in 3-D are doing well at the box office, but none are being broadcast, and many observers are writing off 3-D in the home as an overpriced and overly complicated gimmick. "3-D is a waste of a perfectly good dimension," film critic Roger Ebert wrote in May.
Will the early 3-D adopters get the last laugh, just like the early color TV advocates? A definitive answer would require 4-D glasses to see into the next decade. But between 3-D movies and sports programming—notably the World Cup—and major product investments by the likes of Panasonic, Samsung, and Sony, not just in televisions but also in Blu-ray players, set-top boxes, and other gadgets, it's time to ask the question: What does it take, in time, money, and effort, to put 3-D in your living room?
The answer begins with the glasses.
When you went to see Avatar, Toy Story 3, or Alice in Wonderland, chances are the usher handed you a pair of Polaroid-style "passive" lenses that let vertically polarized light enter the left eye and horizontally polarized light into the right. Or, like RealD's Ray-Ban–like glasses, they used circularly polarized light, in which light waves rotating clockwise pass through the right eyeglass lens while counterclockwise ones pass into the left. Either method results in the illusion of a stereoscopic image onscreen [see sidebar, "Eye Fidelity," at right].
Passive 3-D is great for theater owners, because the glasses are cheap—in bulk, less than $1 per pair. It's pricier in the home, though, because it puts all the complexity in the TV. As of press time (mid-July), South Korea–based LG Electronics had announced the only passive-display consumer 3-D model—its 47-inch LCD screen LD950.
Every other 3-D television set puts the complexity in the glasses, which turn dark over one eye for 8.3 milliseconds while showing the other eye an image. Then for the next 8.3 ms the glasses darken for the second eye while showing the first eye a complementary image. Together these images make up a stereoscopic picture. As far as the relatively slow human nervous system is concerned, the 16.6-ms interval takes place at the same instant. This happens 60 times per second, and it's how "active" 3-D glasses trick the brain into perceiving stereoscopic depth from a flat screen. At $150 to $200 per pair, these battery-powered, microprocessor-equipped LCD glasses turn out to be one of the more expensive components of the 3-D living room, because you'll need one pair per set of eyes—up to $800 for a classic nuclear family.