Screens which are 3D to the touch
Touchscreens could soon start poking back at you. Vibrations that produce a force field beneath your finger could create the sensation of dips and hollows on flat tablet computers like the iPad.
Haptic technology – used to communicate through a user’s sense of touch – has already found its way into mobile devices, says Ed Colgate, head of haptics at Northwestern University in Evanston, Illinois.
These devices tend to be quite basic, however, creating clicking sensations by vibrating the screen or even the entire device. A more sophisticated approach involves vibrating the screen in and out at ultrasonic frequencies, says Colgate. This means the amount of contact between the finger and the screen can be controlled and textures and edges can both be simulated by adjusting this friction, he says.
The problem in these systems is that to get the desired effect your skin has to be moving over the surface. It won’t work if it’s stationary. Colgate’s solution was to superimpose lateral oscillations perpendicular to the vertical ones. “We discovered that if our lateral vibration was at the same frequency as the ultrasonic vibration then you could push the finger,” he says.
The result, besides allowing different textures and sensations to be created, is that the finger can be gently pushed across the surface so that it is coaxed into a particular position. The vibrations can be so slight the user barely notices them, but they stretch skin receptors in the user’s finger in the same way as if they were touching something with depth, fooling the senses into believing the surface is not flat. To the user it can feel like they are touching an indent in the screen, like the “home” button on an iPhone, for example.
Although the effect is still quite weak, this kind of technology has the potential to influence future touchscreens, says Vincent Hayward at the Institute of Intelligent Systems and Robotics at the Pierre and Marie Curie University in Paris, France.
Hayward tried out Colgate’s prototype at the World Haptics Conference in Istanbul, Turkey, in June. “It feels like the surface is coming to life under your fingers,” says Hayward. “And it creates the effect without having to move your finger.” This is particularly useful in a small, cluttered screen, he says.
At the moment the prototype merely creates the effect on a piece of glass, vibrating it at 22 kilohertz with an amplitude of less than a micrometre. “But there’s no reason why we can’t make it work in a touchscreen,” Hayward says.
Read the original article at New Scientist online