An "ultrahaptics" or mid-air tactile feedback prototype has been come up by the Researchers from Britain's University of Bristol. UltraHaptics allows people who interact with a screen to feel what is displayed and will also get invisible information before touching it.

The technology [PDF] works by applying the acoustic radiation force, projected through ultrasonic transducers. These emit sound waves of very high frequency. These sound waves when meet with mid-air creates a sensation on a person's skin.

By combining several such waves, the researchers were able to create multiple points of tactile feedback with different properties that can be differentiated by users.

A researcher was working on the UltraHaptics project. He was a PhD student named Tom Carter. He said existing multi-touch systems with integrated interactive surfaces allow users to use them with their bare hands. However, the people will not be able to feel what is on the screen.

The researchers aimed to build a haptic feedback into present interactive surfaces without sacrificing with the ease of its use and accessibility.

Carter said, "To achieve this, we have designed a system with an ultrasound transducer array positioned beneath an acoustically transparent display".

This arrangement will allow the projection of focused ultrasound through the interactive surface and directly onto the users' bare hands.