Hold onto your remote control: 3-D television is on the way. By the end of the year, most of the major TV manufacturers, including LG Electronics, Panasonic, Samsung and Sony, will be selling displays capable of showing 3-D movies and other programming. Unfortunately, none of the models going on sale this year will eliminate the least pleasant aspect of the 3-D viewing experience—those often uncomfortable and frequently silly-looking spectacles. 3-D TV for the naked eye does not exist—at least not yet.

The coming first-generation 3-D-capable TVs for the most part rely on stereoscopic displays combined with battery-powered, active liquid-crystal shutter system glasses to achieve the effect. These glasses, which look something like the polarized shades handed out at movie theaters, alternately darken and lighten the glasses' left and right lenses, at a speed that is too fast for the eyes to perceive. Meanwhile the TV synchronously displays the corresponding right- and left-eye–specific images.

"Basically, you take a [high-definition] TV and add a liquid-crystal display and modulate the display for the left and right eye," says Pierre Blanche, an assistant research scientist at the University of Arizona's College of Optical Sciences (OSC) in Tucson. "The manufacturers know it's going to work, so there's no challenge."

To go further, Blanche is working with OSC chairman Nasser Peyghambarian and a number of other researchers to develop a 3-D technology that can be viewed sans the special glasses. "We are trying to see how much we can push the science," he adds.

Although glasses-free 3-D TV has been in the works for years, the OSC researchers think it is only a matter of time before it is ready for prime-time—or any other time slot for that matter. The researchers are experimenting with a photorefractive polymer film on which 3-D images can be recorded, erased and replaced with new ones. When carried out quickly enough this process leads to a series of images on the film that deliver three-dimensional action, which can be picked up without special eyewear.

The polymer is a complex composite of copolymers (which act as a photosensitizer and absorb light), a plasticizer (an additive used in plastics to provide strength and flexibility), and other materials formed into a film and melted between 100-millimeter indium tin oxide–coated glass electrodes. Images are recorded onto the polymer using a laser, whose light gets absorbed, creating a charge distribution across the material that modifies the film's refractive index, thereby creating a 3-D image that can be viewed when the film is illuminated.

Turning this polymer into something large enough and that refreshes fast enough to work as a TV is another matter. "Don't expect 3-D TVs without glasses anytime soon," Peyghambarian says. The technology he and his colleagues are developing is about five years away from use as a TV display and probably a decade away from a product that can be brought into the home.

Chinese researchers at Beijing University, Shenzhen-based AFC Technology and the country's National University of Defense Technology are experimenting with holographic 3-D displays, as well. They claimed in the December issue of Optics Letters to have developed a functional holographic screen that is 1.8 by 1.3 meters in size. The researchers place 64 digital cameras along a single axis to capture an object from different viewing angles, then displayed a 3-D image of it using the same number of projectors arranged in the same configuration as the camera array. Each camera was connected to a video server, which recorded the images at 64 different angles through the array, corrected image distortions, synchronized image frames, and controlled the projector array that cast the 3-D images onto the screen. Using this approach, it is possible to realize a fully continuous naked-eye 3-D display in the near future without theoretical and technological barriers, AFC Technology President Frank Fan wrote in an e-mail to Scientific American.

Sony unveiled a 360-degree viewable holographic display—130 by 270 millimeters—last year that produces 3-D images without the need for special eyewear, but the technology remains in the research and development stage for now, according to company spokeswoman Chisato Kitsukawa.

Other approaches to native 3-D include autostereoscopic and multiview displays. The problem with these technologies is that they require light-directing technologies (such as lenticular lenses that magnify different images when viewed from different angles) that have to be aligned perfectly and tend to reduce a display's resolution, says David Wertheimer, CEO and executive director of the University of Southern California's Entertainment Technology Center.

"It is hard to imagine that glasses-free displays will match glasses-based displays in terms of resolution, quality and frame rate anytime soon," Wertheimer says. Native 3-D technologies are seductive because viewers would not have to worry about glasses, but it may be a long time before the experience with glasses-free displays is as good as what is available through the standard stereoscopic systems available today.

Dutch* electronics-maker Philips had been experimenting with an LCD TV that relied on a lenticular lens placed over the screen to generate the 3-D effect without glasses but shut that project down last year. "We wanted to further the technology, but due to market factors it is less commercially attractive to maintain that business," says Hans Driessen, senior communications manager for Philips Research. "Over time, 3-D without glasses will bring the ultimate experience to the home, but in the meantime we are now looking to develop 3-D displays that do require glasses." The company demonstrated its stereoscopic 3-D TV and glasses last year at the IFA consumer electronics show in Berlin and plans to make an additional announcement regarding the product by the end of the year.

Philips's approach was to place a lens over an LCD panel to create depth for each pixel, but critics say that the company's technology was unable to provide a sufficiently wide field of view. "With true 3-D, you would be able to move around and be able to see it and have excellent resolution from a number of different angles," Peyghambarian says.

The incentive for TV-makers to get the technology right is there, as Hollywood continues churning out successful 3-D movies such as Avatar and Up, both of which were nominated for Oscars this year. There are plans for 50 wide-release 3-D movies in 2010, up from 20 last year.

"We are all excited about the potential for glasses-free displays," Wertheimer says. "However, for sure, we'll be wearing glasses for the foreseeable future."

*Correction (3/06/10): This article originally misstated that Philips is a Danish company.