Touch screens are ubiquitous today. But a common complaint is that the smooth surface just doesn’t feel as good to use as a physical keypad. While some touch-screen devices use mechanical vibrations to enhance users’ experiences of virtual keypads, the approach isn’t widely used, mainly because mechanical vibrations are difficult to implement well, and they often make the entire device buzz in your hand, instead of just a particular spot on the screen.
Now, engineers from three different groups are proposing a type of tactile feedback that they believe will be more popular than mechanical buzzing. Called electrovibration, the technique uses electrical charges to simulate the feeling of localized vibration and friction, providing touch-screen textures that are impossible to simulate using mechanical actuators.
Their touch panel is made of transparent electrodes on a glass plate coated with an insulating layer. By applying a periodic voltage to the electrodes via connections used for sensing a finger’s position on the screen, the researchers were able to effectively induce a charge in a finger dragged along the surface. By changing the amplitude and frequency of the applied voltage, the surface can be made to feel as though it is bumpy, rough, sticky, or vibrating. The major difference is the specially designed control circuit that produces the sensations.
A Finnish company called Senseg has implemented electrovibration in touch screens and closed deals with three companies to incorporate the technology into products.