The hardest part about typing on touch-sensitive screens is not being able to feel where one button ends and another one begins. A team of researchers from MIT could be on the path to fixing that by creating tactile buttons right on a touch screen. MIT Technology Review has the details of Gel Touch, the researchers' tactile touch display prototype.
The researchers put a thin, transparent film made from indium tin oxide (ITO) on a touch display, and then spread a heat-sensitive hydrogel over it, along with a grid of electrodes. Using the ITO layer, the researchers could create shapes by running current between pairs of electrodes, which heat the gel in a small area to 32 degrees Celsius (around 90 degrees Fahrenheit).
Clear and jelly-like in its un-activated state, the gel turns white and stiff in its activated form, and pops up to form buttons. The researchers say the gel is about 25 times more stiff in its activated form, and it expands enough for users to feel it. In blind tests, subjects were able to identify with nearly 95% accuracy where a button was just by feel.
More details can be found in the team's paper (PDF), which will be presented at a user interface conference in November. Lead author Viktor Miruchna says that with the hydrogel, "you basically can have unlimited shapes or structures or whatever you want."
There are some obstacles to overcome, though. It takes about two seconds for the gel to switch states using the ITO layer. Hong Tan, a professor from Purdue University who studies haptic technology, says that's pretty slow, and that cooling the gel quickly to make buttons disappear could be tricky. Miruchna agrees, saying that there is more work to be done before Gel Touch can be commercialized, but he says that the team already has more ideas to test out.