In 1980, when I was 13, I wore weird glasses at the movies to watch Dracula get speared on a 15-foot lance. His heart looked like it was dangling inches from my face. It was my first 3-D experience. After the show, I remember listening to my best friend, a sci-fi geek, tell me about holographic TV, like that chess game on Star Trek.

Sixteen years later, the idea of holographic television has faded from sight, but a viable 3-D entertainment system is about to hit the market. "This is truly a 21st-century technology," says Parviz Soltan, a researcher at the US Navy's Command, Control, and Ocean Surveillance Center outside San Diego and the main developer of the prototype.

Visualize a double-helix-shaped television screen. Now spin that screen at 10 rotations a second - fast enough to make it invisible to the human eye. Put the double helix into a clear cylinder and stick a mirror on top. Using red, green, and blue lasers - the same tripartite colors used in ordinary television systems - you can project an image onto the mirror and into the cylinder. The beam hits the helix and creates a visible point of light. Currently there are 120,000 possible points, called voxels (think 3-D pixels), that can be illuminated on the helix, and the computer running the show is fast enough to change the image up to 20 times a second.

Most of Soltan's early work wasn't directed at television but at designing better monitors for air traffic controllers. Now he has created a working, three-dimensional version of a radar screen, which will undergo testing with the Federal Aviation Administration.

Meanwhile, the NEOS Corporation is developing a commercial version of Soltan's 3-D TV. Museums, theme parks, and planetariums have expressed interest, but to get on the bandwagon, they'll need pockets as deep as Disney's. When 3-D TV hits the market early next year, the price tag for a small version is expected to be around US$80,000. Thereafter ... the sky is the limit.