Not long ago we looked at Peratech’s QTC technology. You might remember it as a functional ink that’s highly sensitive to pressure. Our focus at the time was how the technology works; designs seemed to be in process at that point.
Shortly after, they announced a touch screen solution. Because of the ink’s sensitivity, they can actually put the touch sensor behind the screen, reducing the cost of the screen itself and getting the electronics out of the way on the edges. They can also make the screens arbitrarily large. But more importantly, the touch layer is no longer in the light path, meaning that it doesn’t absorb any light, meaning that power can be reduced for the same effective light output.
They recommend it in particular for e-paper and OLED screens, although it will work with anything except LCD (which doesn’t like to be pressed). You need to deflect by about a micron for it to register, but it can also measure the amount of deflection, meaning you get a pressure/z-axis component as well as the usual x and y components of the press.
You can find out more in their release.