Thanks to a new flexible sensor that is capable of detecting differences in touch, bendable and foldable devices may soon become a reality. We’re talking smartphones, tablets and even TVs.
This ground-breaking sensor was created by a team of researchers from the University of British Columbia in Vancouver. It’s made of a highly conductive and super-flexible hydrogel placed between two layers of silicone. It is responsive to different kinds of touch even when it’s bent, folded or stretched. It can be made into any size or shape. And it’s a low-cost material too.
All these features make the sensor ideal for future devices, the researchers said. And it’s not just limited to electronic devices. The material can potentially be used on other items like clothing, wearables, steering wheels, roads, and even on robots.
Previous attempts to invent flexible touchscreens have not been successful because even if the material used is super-thin (i.e. nanometers wide), it is unable to operate well and distinguish between different kinds of touch when it has been deformed. This poses a problem, of course, because it cannot differentiate between a deliberate touch from a finger, and its own stretching movement.
This latest material, though, seems to have overcome this challenge. Tests showed that the touchpad could detect several fingers simultaneously (which is necessary to make the zoom function work on a smartphone or tablet). When it was folded in half, it continued to work normally. And it didn’t falter even when coffee was spilled on it.
To make the touchpad, the team used hydrogel, a material that has a similar structure with what soft contact lenses are made of. They added salt to it so ions (electrically charged particles) could flow within the material and generate an electric field. They then embedded the hydrogel in the silicone layers.
When a finger approaches the hydrogel, an interaction happens between the finger and electric field, and the hydrogel can detect this. In other words, the hydrogel can distinguish between an outside interaction (like a finger touching the touchpad), and movement that’s simply its own self flexing.
The prototype the team created measures five centimeters by five centimeters. That’s a bit small, but it can easily be scaled up and it won’t cost that much. As estimated by the researchers, the materials they used cost about $1 per square meter.
As Mirza Saquib Sarwar, one of the researchers and a PhD student in electrical and computer engineering at UBC, said: “It’s entirely possible to make a room-sized version of this sensor for just dollars per square meter, and then put sensors on the wall, on the floor, or over the surface of the body—almost anything that requires a transparent, stretchable touch screen.”
UBC Professor John Madden — also Sanwar’s supervisor — added that it might be feasible to integrate the sensor in robotic skins so human-robot interactions will become safer.
“Currently, machines are kept separate from humans in the workplace because of the possibility that they could injure humans. If a robot could detect our presence and be ‘soft’ enough that they don’t damage us during an interaction, we can safely exchange tools with them, they can pick up objects without damaging them, and they can safely probe their environment,” said Madden.
The research has been published in the journal Science Advances.
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