UltraHaptics creates touchable sound waves

Researchers at the University of Bristol's Interaction and Graphics (BIG) group have created a system for creating haptic feedback in mid-air. The use of ultrasonic vibrations is a new technique for delivering tactile sensations to the user. In involves a series of ultrasonic transducers that emit very high frequency sound waves and when all of the waves meet at the same location at the same time, they create sensations on a human's skin.

By carrying out technical evaluations, the team have shown that the system is capable of creating individual points of feedback that are far beyond the perception threshold of the human hand. The researchers have also established the necessary properties of a display surface that is transparent to 40kHz ultrasound.

Thus when these haptic sensations are projected through a screen and directly onto the user’s hands this allows them to ‘feel’ what is on the display. This opens up exciting avenues in any markets where displays and digital signage are used, especially for retail.

“Current systems with integrated interactive surfaces allow users to walk-up and use them with bare hands,” Tom Carter, PhD student in the Department of Computer Science’s BIG research group.
“Our goal was to integrate haptic feedback into these systems without sacrificing their simplicity and accessibility.”
“To achieve this, we have designed a system with an ultrasound transducer array positioned beneath an acoustically transparent display. This arrangement allows the projection of focused ultrasound through the interactive surface and directly onto the users’ bare hands. By creating multiple simultaneous feedback points, and giving them individual tactile properties, users can receive localised feedback associated to their actions.”

The results from two user studies have demonstrated that feedback points with different tactile properties can be distinguished at smaller separations. The researchers also found that users are able to identify different tactile properties with training.

Finally, the research team explored three new areas of interaction possibilities that UltraHaptics can provide: mid-air gestures, tactile information layers and visually restricted displays, and created an application for each.