For the past two years, Apple has been slowly retiring Touch ID – its fingerprint biometric sensor built into the home button. When the iPhone X dropped the home button entirely, Touch ID had nowhere to live, and the iPhone XS, XS Max and iPhone XR all followed suit in 2018.
Face ID is the replacement, though it looks like Apple may not have completely given up on the fingerprint as a means of authentication. But neither is the company in any hurry to bring back the home button. A patent uncovered by Apple Insider shows a new take on the technology that would allow the user to unlock their device by pressing their finger against any part of the screen.
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That last part of the sentence is significant. In-screen fingerprint readers are relatively new (see the OnePlus 6T and Oppo RX17 Pro for examples), but they require you to put your finger on a specific area of the screen. With Apple’s patent that isn’t the case, thanks to acoustic imaging.
The patent title is “Acoustic pulse coding for imaging of input devices”, and it describes how sound can be used to recognise a fingerprint. In short, sound pulses would be sent out via an array of acoustic transducers which would then reflect from the ridges of the skin, allowing the device to build a full picture of the fingerprint.
Aside from the flexibility of being able to put your fingerprint anywhere on the screen, this method could have a few other advantages. Components could be reduced in thickness, and speed of authentication could be upped too.
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Before you get too excited though, a quick reality check: Apple files a ridiculous number of patents every year. Last year, it filed nearly 800 adding to a stack of some 85,000 in total. Not all of these see the light of day, and there’s every chance that this idea will sit gathering dust in a drawer somewhere.
All the same, it’s encouraging for fans of the fingerprint that Apple is still thinking along those lines. Face ID may be quick and effective, but the more authentication options the better.
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