A team of researchers at the University of California, Berkeley, has developed the first user-interactive “electronic skin” that responds to pressure by instantly emitting light.
“The goal is to use human skin as a model and develop new types of electronics that would enable us to interface with our environment in new ways,” explains Ali Javey, an electrical engineering and computer science professor at Berkeley and leader of the e-skin research team.
The electronic skin is made up of a network of sensors placed on thin plastic substrates that can spatially and temporarily map pressure. Javey describes the network as an array of 16 by 16 pixels, each one equipped with a carbon-nanotube thin-film transistor (TFT), a pressure sensor, and an organic light-emitting diode (OLED) on top. When the sensor detects touch, the TFT powers up the OLED, which then emits red, green, or blue light. The harder the pressure, the brighter the light will be. The end product is a thin, flexible material that can be placed on top of all sorts of surfaces.
Takao Someya, creator of a different type of electronic skin and an associate professor at the University of Tokyo’s Quantum Phase Electronics Center, was particularly impressed with the team’s use of carbon nanotubes. “One of their great achievements is to demonstrate feasibility of carbon nanotube field-effect transistors for large-area, flexible electronic applications,” he says.
Javey, who has been working on developing the e-skin for the past five years, has high hopes for his new material. He’d like to create user-interactive wallpaper or a dashboard that responds to cues such as the driver’s eye or body movements. When asked to describe how the interactive wallpaper would work, Javey referred to the scene in Minority Report in which Tom Cruise controls a computer by moving his hands. “That’s the direction we’re heading to—a new type of interfacing,” he says. “Getting rid of the keyboard, getting rid of display, and become in sync with our surroundings so that you don’t have these physical components sitting around. It’s part of the table; it’s part of the wall.”
In Javey’s proposed system, light sensors would read hand and body motions, and pressure sensors would respond to different degrees of touch. But there’s a good deal of work that must be done before we’ll be seeing interactive wallpaper, he says. “We know how to make complex systems on tiny silicon chips, but on plastic it’s a whole different story,” Javey says. “It’s still not a very complex system we have shown, but it’s still one of the most complex systems we have to date on plastic.” He adds that his team is interested in integrating light sensors as well as data-processing and wireless-communication capabilities onto the substrates.
“This is an inspiring development in the plastic device technology, which is likely to make many everyday experiences more stimulating,” says Nicholas Kotov, a professor at the University of Michigan who is working on flexible, stretchable electronics.
John Rogers, a materials science professor at the University of Illinois at Urbana-Champaign, says “the work illustrates the extent to which research in nanomaterials, once confined strictly to fundamental study on individual test vehicles, is now successfully moving toward sophisticated, macroscale demonstrator devices, with unique function. The results provide more evidence that the field is headed in the right direction.”