How Electrovibration Technology Will Add Texture to Touchscreens

By Wesley Fenlon

A technology called electrovibration could replace the small motors that currently provide haptic feedback in touchscreen devices.

It's not a touch screen. It's a feel screen! Little motors embedded in smartphones and tablets vibrate to apply the haptic feedback that adds sensation to typing on a virtual keyboard. More than a year ago a company called Senseg demoed an alternative using an electrostatic field, and not a vibrating motor, to create tactile feedback. And here we are again: Senseg's still working on E-Sense, and in another year the technology might even find its way into some real products.

Senseg demonstrated the electrostatic field for Cnet in the form of a prototype tablet and explained how the field plays with the friction between your finger and the screen to create the sensation of texture. It's cool stuff--read on to see exactly how it works.

Senseg's Dave Rice provides a brief explanation of how the sensation differs from motorized haptic feedback, but here's a more sciency breakdown. Senseg is not the first company to experiment with the technology behind E-Sense, though they might be the first to get a product to market. The underlying effect at work is called electrovibration:

The 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.

As Senseg's own site explains, the tactile experience comes from two components: a coating layered atop a touchscreen and electronics that modulate the electrostatic field and produce textures. Senseg's Tixel is " the means by which Senseg’s technology transmits electro-vibration stimulus. It is an ultra-thin durable coating on the touch interface that outputs tactile effects." The hardware inside a device "modulates the signal for varied intensities of tactile sensation, types of tactile effects and provides accurate spatial resolution over the entire Tixel surface area."Senseg hopes to have its tactile feedback technology in phones or tablets in 1-2 year's time. With some smart design, it could really improve the functionality of touchscreens used in other fields, as well. For example, touchscreens in cars have encouraged drivers to look away from the road to control music playback. With varying degrees of feedback, we could do the same thing without ever taking our eyes off the road.