The concept described in Apple's new patent application is quite different, relying on actuators to physically provide haptic feedback on a touchscreen, rather than giving sensations through an electric field. But it demonstrates Apple's continued pursuit of providing users with some sort of physical feedback when using a touchscreen device.
"The user can typically only feel the rigid surface of the touch screen, making it difficult to find icons, hyperlinks, textboxes, or other user-selectable elements that are being displayed," Apple's filing reads. "A touch-based user interface may help a user navigate content displayed on the display screen by incorporating haptic feedback."
Rather than simply vibrating the device when a button is tapped, as some touchscreen devices do, Apple's solution could utilize piezoelectric actuators for "localized haptic feedback." This would allow the user to feel a virtual button on their fingertips.