Apple granted U.S. patent for acoustic fingerprint imaging technology
Apple has received a patent for acoustic fingerprint imaging technology which is accurate enough to effectively replace existing Touch ID optical readers, confirming rumors that Apple will do away with the iPhone home button, according to a report by Apple Insider.
Initially filed in August 2015, U.S. Patent No. 9,747,488 credits Mohammad Yeke Yazdandoost, Giovanni Gozzini and Jean-Marie Bussat as its inventors.
In its application covering “Active sensing element for acoustic imaging systems,” Apple details a method of collecting biometric data, specifically a fingerprint, through ultrasonic transmission and detection.
Collected fingerprint images, once processed, can be applied to user authentication in a similar manner as Touch ID.
But unlike Apple’s existing fingerprint scanning hardware, acoustic imaging technology does not need to obtain optical access to an evaluation target, which means it can position ultrasonic transducers beneath operating components like a display.
The patent describes the acoustic imaging system as incorporating several piezoelectric transducers arranged in a pattern near the bottom surface of a given substrate.
Arranged in such a way as to collect image data of an object engaging the top substrate surface, such as a finger or stylus, these components transmit an acoustic pulse toward the top substrate surface.
Part of the acoustic pulse is subsequently reflected off the top substrate back toward the transducer array, where the returning acoustic waves can be analyzed to identify the image of a target.
The patent provides the example of a finger introducing an acoustic impedance mismatch, or acoustic boundary, between itself and the top substrate surface.
A fingerprint’s ridges and valleys act as different acoustic boundaries, soft tissue-substrate and air gap-substrate, respectively, which generates distinct acoustic output that can be detected by the sensing elements.
After being collected at the piezoelectric transducer array, reflected acoustic pulses are converted into electrical signals and analyzed. In some versions, electrical signals correspond to a single pixel of a larger sub-image.
It is unclear whether Apple will implement the acoustic imaging technology into the upcoming iPhone 8 product, however, several rumors surfaced earlier this year that Apple was planning on introducing a sub-screen fingerprint reader in the upcoming smartphone.
An embedded solution would effectively replace the home button, allowing the company to make room for a full-face OLED display.
Recent reports cite insider claims that Apple has abandoned plans to integrate Touch ID into the smartphone entirely, replacing it instead with advanced facial recognition technology powered by new depth-sensing camera hardware.
Last month, Apple released firmware for its HomePod smart speaker which contained several iPhone 8 design references, including the existence of infrared face detection in the BiometricKit framework.