Temperature-Shifting Touchscreen Offers High-Fidelity Haptic Feedback Through Friction Control
Adjusting its temperature to increase and decrease friction, this touch interface can simulate a range of surface textures.
A team of researchers at Texas A&M has published work on improving the quality of touchscreen interfaces by giving them the ability to provide shape and texture feedback — using variable temperature surfaces.
"We can view digitally recorded or remotely transmitted audio and video on a screen with great detail," explains Cynthia Hipwell, professor and co-author of the research, of the problem the team set out to solve. "We do not yet have that same capability with touch on a touchscreen. Imagine you could feel the skin of a snake that lives on another continent or the fabric of clothes you want to buy online."
"The touch sensations that would be required to really immerse yourself into a reality that is fully digital requires huge advancements in touch perception," adds Jonathan Felts, associate professor and co-author. "What we’ve done is essentially created an entirely new way to modulate the perception of touch that hasn’t existed before."
In its latest paper, the team has taken a somewhat unusual approach to haptics: Rather than using mechanical feedback, such as a surface capable of deformation or something as simple as a vibration motors, the team's work relies on changing the temperature of the touch-sensitive panel itself — and in doing so controlling the friction between the user's finger and the device.
"Experiments showed that finger friction can be increased by ~50 percent with a surface temperature increase from 23° to 42°C [around 73° to 108°F]," the researchers explain," which was attributed to the temperature dependence of the viscoelasticity and the moisture level of human skin. Rendering virtual features, including zoning and bump(s), without thermal perception was further demonstrated with surface temperature modulation."
While the system proved efficacious in the lab, however, there's work still to be done before it arrives in a smartphone near you. "Can it be scaled down? Can it respond quickly enough? Can it mimic a wide range of surfaces? Can it be affordable?
"We think these are fair criticisms," Felts admits, "yet we look forward to using this phenomenon to improve our basic understanding of haptic feedback and pursuing miniaturization and commercialization avenues."
The team's work has been published under open-access terms in the journal Science Robotics.