Long-standing rumors that Apple plans to embed the Home button into the display of future iPhones became more concrete when Bloomberg, the WSJ and NYT all reported that Apple plans make this move in 2017.
We’ve seen a succession of Apple patents for this technology, and another one published today appears to describe a technology that would allow a fingerprint to be recognised almost anywhere on the screen, not just in a fixed location …
The patent (spotted by Patently Apple) describes how ‘electric field differences between ridges and valleys of the fingerprint’ could be applied to a capacitive screen. In it, Apple outlines the reason for the company wanting to combine the Home button with the display.
In the case of fingerprint recognition systems that include arrays of capacitive sensing elements to detect the fingerprint images, i.e. capacitive fingerprint sensors, there may be a number of reasons for these components to axially aligned with other components of the consumer electronics device, such as display stacks and touch screens, not the least of which is an interest in avoiding assigning valuable surface space exclusively to an component that may only be used briefly during the process of identifying the user.
A previous patent described a different method of achieving the same aim, via ultrasound imaging. Chinese brand Xiaomi recently launched a smartphone using this technology (video). Apple said that technique is more accurate than current-gen Touch ID, but it appears to require a fixed location.
From the drawings (above), however, it appears that the ‘capacitive fingerprint sensor with electrostatic lens’ would allow detection across either the entire display or a substantial portion of it.
The touch-sensitive Home button used in the iPhone 7 is likely intended a stepping-stone toward a version that can be embedded in the display itself. It’s not yet known what next year’s iPhone will be called, with iPhone 8 seen as the most likely contender for what is set to be a substantial redesign, but other names have been suggested. KGI recently reported ‘increasing likelihood’ the phone will be mostly glass, with stainless steel used for ‘premium models.’