Rumours strongly suggest that Apple will replace the Touch ID home button with alternative bio-recognition hardware when it launches an OLED version ‘iPhone 8’ later this year. Although the technology enabling that transition is not yet known, a new Apple patent application published today by the US Patent and Trademark Office (USPTO) indicates just how the company might achieve that (via AppleInsider).
Titled “Acoustic imaging system architecture”, the filing details a method by which a conventional capacitive fingerprint sensor like Touch ID might be replaced by an array of acoustic transducers laid out beneath a device display or its protective housing. Apple’s acoustic imaging system can be configured to read a user’s fingerprint.
According to the filing, ridges in a finger pad introduce an acoustic impedance mismatch that causes the mechanical waves generated by a transducer to reflect or diffract in a known manner.
Like other biometric security solutions, the digital maps obtained by an acoustic imaging system are ultimately compared against a database of known assets to authenticate a user.
Thanks to its design, the acoustic system can be installed practically anywhere in a device chassis, including directly under a display. Other potential points of integration include a screen’s perimeter or bezel, around buttons and in non-input areas of a housing, like a rear chassis. The latter coupling method would allow an example system to sample a user’s entire handprint.
Apple’s acoustic imaging patent application was first filed for in August 2016.