Researchers at the University of Tokyo have developed a holographic projector that displays three-dimensional virtual objects you can feel with your bare hands.

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The system consists of a Holo display (developed by Provision Interactive Technologies), a pair of Wii Remotes that track the position of the user's hand in front of the screen, and an "Airborne Ultrasound Tactile Display" unit that shoots focused ultrasonic waves at the hand to create the sensation of pressure on the skin.

By controlling the movement of these focused ultrasonic waves -- which can produce up to 1.6 grams-force of pressure within a 20-millimeter-wide focal point -- the projector can recreate virtual objects that seem to have physical mass. In the video above, the projector displays a tangible virtual bouncing ball, raindrops, and a small creature that runs around on the user's hand.

The tangible hologram projector is now on display at SIGGRAPH 2009 in New Orleans.

[Link: Touchable Holography (PDF) via @GreatDismal]