SAN FRANCISCO: In a museum in Tampere, Finland, Ismo Rakkolainen's fog machine conjures up the Mona Lisa on an invisible sheet of water particles.
Thousands of miles away in Hermosa Beach, California, a graduate student passes his hand through an image of a DNA strand produced -- apparently out of thin air -- by a modified video projector.
The two inventions represent the latest front in advanced computer displays -- eliminating the screen altogether.
While unlikely to replace the desktop computer monitor, so-called walk-through displays could eventually be put to use in product showrooms, museums, and military training facilities.
"This is something that people have been dreaming about for a long time," said Chad Dyner, 29, a graduate student at the Massachusetts Institute of Technology and inventor of Heliodisplay, one of the prototype display systems. "Ever since the movie 'Star Wars' came out and there was a distress call from Princess Leia," -- generated in thin air by the robot R2D2 -- "people all over the world have been wanting one of these."
Dyner has disclosed few details about how his Heliodisplay works. The machine modifies the air above a video projector, creating a working, 27-inch screen that can display any kind of video. The image is two-dimensional, can be seen from several angles, and can be manipulated by hand.
The display is less bold than a normal computer screen, Dyner admits, but he said he hopes to bolster the image quality in future prototypes. Also, a bright light shines in the eyes of viewers who get too close to the machine, a flaw he said he knows how to remedy.
Dyner has hired two former investment bankers to find businesses that could use a Heliodisplay, and he has already received inquiries from a large Japanese display company and the U.S. military, not to mention 250,000 hits on his Web site (http:/www.io2technology.com).
In Finland, a device called the FogScreen has generated a lot of buzz, and turned heads at this year's Siggraph, an industry conference on display technologies. A popular Finnish mime has even integrated the FogScreen into a performance.
The FogScreen generates an image onto a cloud of water vapor diffused into the air. Developed by two virtual reality researchers at Tampere University of Technology in Finland, the FogScreen is being marketed to companies that rent equipment to trade shows and other public events.
"I have been researching this area quite a lot so I have seen a lot of good ideas and all kinds of nice ideas and nice patents, but very few become real products," said Rakkolainen, a co-inventor of FogScreen along with Karri Palovuori. "I think our technology is already quite far so I think it will become a real product."
Mika Herpio, the chief executive of FogScreen, said his machine could cost as much as $100,000, but that the price could drop in quantity production. Advanced prototypes of the FogScreen have been built, and commercial production is expected to start later this year.
Many advanced display technologies have impressed the public and yet failed to turn a profit. The walk-through screen, despite a surge in interest, may also fail, said Chris Chinnock, senior analyst at Insight Media, which conducts market research on video projection equipment.
"There's some interesting potential in this space, that's for sure," he said. "But having seen many other ideas kind of fizzle that also seemed intriguing at this stage, you have to take a more jaundiced wait-and-see attitude."
"The whole general display industry is just littered with dead bodies everywhere, and success stories, too," he said.