Touchscreens have become increasingly sophisticated over several generations of devices. The latest Apple iPhone with 3D touch adds a new dimension to context sensing by detecting pressure as well as position and movement gestures. It feels light years away from early handhelds like Palm PDAs, with their styluses and one-touch resistive sensors.
The audible squeak from those screens was soon superseded as smartphones turned to haptic technology, using vibration to replace the lost physical sensation that confirms when a button has been pressed.
While touchscreens have quickly become remarkably sleek, responsive and feature-rich, haptic technology has remained relatively crude. Many smartphones today still use either an Eccentric Rotating Mass (ERM) or Linear Resonant Actuator (LRA) that vibrates the entire device in the user’s hand. This has restricted opportunities to deliver more advanced user experiences, not only on smartphones but also on devices like tablets and game controllers.
Compared to the speed and precision of the latest touchscreens, conventional haptic mechanisms have not kept pace. The feedback provided continues to serve only basic purposes – such as confirming to the user that a touch command has been received and the device will act on it, or sending a warning during gameplay. The limited capabilities of these mechanisms mean they can be unsubtle and in some cases quite excessive in relation to the gesture that’s been made. Surely it could be better: a faster-responding, more gentle, more localized mechanical response could open up all kinds of possibilities to deliver more pleasing user experiences.
The term haptic comes from the Greek haptikos, or sense of touch. By definition, then, the haptic system should deliver performance that is just as smooth and sophisticated as the touchscreen. It should all be one seamless touch experience. Instead, as the screens have become sleek and glossy and responsive and 3D, the overall tactile sensation has become unbalanced, relying too heavily on the user’s visual perception of touch.
Arguably, there hasn’t been tremendous user demand for better haptic systems. Few consumers think too hard about how “ring and vibrate” could be better. But things could soon change as touchscreens become more commonplace in our cars. Volvo is among the first to follow Tesla’s lead by designing a massive 17-inch touchscreen into the center console for access to the car’s advanced controls and infotainment features, and other manufacturers are sure to follow. We can expect professional road testers and early adopters soon to close their gaping mouths and start demanding to be able to use the touchscreen more easily while on the move.
The latest piezoelectric actuators could be about to unlock some significant advances in the quality of haptic applications, both in-car and on handhelds like smartphones, tablets and controllers. Piezoelectric actuators physically deform when an electric field is applied, and can be made in various shapes and sizes such as small disks or rectangular strips. They are extremely fast-acting, with startup times of 5ms or less, and the entire response can be completed within the time it takes for an ERM or LRA actuator to spin up. This enables haptic responses that meld seamlessly into the overall user experience. It is also far more power efficient, which is good news for battery life. On the other hand, this type of actuator can generate as much as double the vibration strength of an ERM or LRA if needed, and so is well suited to use in larger smartphones as well as tablets.
What’s really clever is that, when used in the right way, they can give precise tactile feedback such as simulating notches on a volume slider or rotary tuning dial. This is the science behind Bosch’s NeoSense technology, which the company displayed earlier this year at CES in Las Vegas. Its ability to simulate different textures allows drivers to feel for buttons and adjust the controls to their liking without taking their eyes off the road. It can work for handhelds too, confining the physical feedback to the screen only instead of making the entire device buzz and shake.
It’s sometimes difficult to see how today’s consumer tech could possibly get any better. And then the next thing arrives. Piezoelectric haptics could soon be driving touch experiences that are everything we can imagine, and more.