Qualcomm has demonstrated a working under-display fingerprint reader, lending confidence to the idea that Apple will have its own version ready for the iPhone 8.

So far, the idea of embedding a fingerprint reader into the display of a device has been the stuff of patents and promises. The closest we’ve got to a working product was when Xiaomi showed off a very early version of the tech on a phone launched last year …

The mi 5s used an ultrasonic fingerprint reader embedded into the glass, but it was a bit of a cheat as it wasn’t actually part of the display area. It also used an indent, which Xiaomi said was to help locate the reader by touch, but may have been there because early ultrasonic readers could cope with only an extremely thin layer of glass.

The sensor demonstrated by Qualcomm works under 800 micrometers of glass, twice as thick as the previous generation used in the mi 5s. It can also work through metal.

CNET notes that the sensor can do more than read a fingerprint.

Engadget tried it out on a prototype Vivo phone, shown in the GIF below, and reported that it had a couple of issues.

Vivo said that this was a financial rather than technical constraint: it would be possible to apply fingerprint sensors across the entire screen, but this would be significantly more expensive. The company is considering a compromise option of covering the bottom half of the screen.

Qualcomm’s timings suggest that the technology will appear in the first Android phones from early next year, meaning Apple could be first to market if the iPhone 8 does indeed have the rumored embedded fingerprint reader.

The sensor uses ultrasonic imaging, which Apple has previously described as ‘the most accurate finger-scanning technology.’ Apple has at least two patents on its approach to this.

If Apple is unable to achieve the yields needed for volume production, embedding a fingerprint reader into a physical button is one possible alternative, and a MacBook Pro-style Touch Bar another, though an in-display version is still widely expected.

Photo: Engadget