Researchers at Bristol University in the UK have been working on a new technology which provides haptic feedback in mid-air above an interactive surface.

UltraHaptics Uses Ultrasound to Bring Tactile Feedback to Digital Touchscreens

Moving beyond the static office computer, which is a digital extension of the traditional office with its drawers and simple functions, mobile technology now offers an increasingly intimate, personal and tailored relationship with the user. In parallel we have seen the arrival of more sensitive interaction, moving from the simple mouse-click to communication technologies based on sound, and nowadays there even exist screens which approximate to the full human visual experience. It all began with touch, and it now appears that the next step will mark a return to the primacy of touch. This at least is what emerges from a reading of research on haptic technologies carried out at the University of Bristol. However, the recently-unveiled UltraHaptics system somewhat overturns the established natural codes on how our senses actually work. What does this mean? Quite simply, UltraHaptics employs focused high-frequency sound waves to simulate the sensation that you are touching a certain item on the screen even though you have no direct contact whatsoever with the screen.


‘Touching’ sound


UltraHaptics technology basically simulates material objects, giving us for instance the sensation of touching a wooden object displayed on the screen and feeling the grain and the contours. What is really happening though is that we are touching sound waves emitted through the screen. Using stronger or weaker ultrasound impulses located according to the effect the system wishes to produce, the pressure differential in what is known as the ‘acoustic radiation force’ – the force generated when ultrasound is reflected – causes the mechano-receptors under our skin, e.g. in the fingers, to react. The system creates what the researchers call ‘haptic feedback’, a touch-reaction, such as when you push a button and feel its resistance against your finger. With UltraHaptics that would be virtual resistance, generated in mid-air without actually touching the display screen at all. The researchers found haptic feedback to be optimal up to 35 cm above the display surface. So in the near future we can envisage the development of interactive touchscreens that you do not actually need to touch. The researchers promise that as their system can be adapted and uses relatively light materials it will be suitable for use with all types of screens, whatever their size, and whether in a vertical or a horizontal position.


A total sensory experience?


This research also holds important implications for the gradual disappearance of physical display screens as a means of visually projecting the technology. If there actually is a display surface, in one form or another, the UltraHaptics technology promises full interaction without any contact with the screen, just by feeling each action against one’s fingertips. One might then say that all that is needed for the computer of the future is a holographic projection. However, without letting our imagination roam too far, we can already envisage a range of highly practical applications such as tools for blind or partially-sighted people, though no commercial application is being developed at this moment in time. Taking a much broader view, we can imagine that this ultrasound solution is one more step, one stage further towards a transition from a targeted intellectual approach to the man-machine relationship to a more sensory, intuitive way of controlling technological tools.

By Quentin Capelle