The heliodisplay is an interactive planar display. Though the image it projects appears much like a hologram, its inventors claim that it doesn't use holographic technology, though it does use rear projection (not lasers as originally reported) to project its image.
Description of Heliodisplay
It does not require any screen or substrate other than air to project its image, but it does eject a water-based vapour curtain for the image to be projected upon. The curtain is produced using similar ultrasonic technology as used in foggers and comprises a number of columns of fog. This curtain is sandwiched between curtains of clean air to create an acceptable screen.
Heliodisplay moves through a dozen metal plates and then comes out again. (The exact details of its workings are unknown, pending patent applications.) It works as a kind of floating touch screen, making it possible to manipulate images projected in air with your fingers, and can be connected to a computer using a standard VGA connection.
It can also connect with a TV or DVD by a standard RGB video cable. Though due to the turbulent nature of the curtain, not currently suitable as a workstation.The Heliodisplay is an invention by Chad Dyner, who built it as a 5-inch prototype in his apartment before founding IO2 technologies to further develop the product.