Qualcomm to release under-screen fingerprint sensor

Qualcom has announced a fingerprint ID sensor designed to be fitted underneath smartphone and tablet screens such that it would work with wet fingers or underwater as well it can measure a person's heart rate.

However, one expert said that Apple could still beat Qualcomm to market with a screen-integrated sensor of its own.

Qualcomm unveiled its innovation at Mobile World Congress Shanghai. Its sensor works by emitting ultrasonic sound waves, which then bounces back on to the sensor with different reflection strengths depending on whether they hit the fingers' ridges or valleys.

An earlier version of the tech was used by Xiaomi to embed a fingerprint sensor under a glass bezel at the base of its Mi5 smartphone. But it partnered with Vivo to show off a prototype handset featuring the new part at the Shanghai expo.

The tech blog Engadget said the demo unit worked but was noticeably slower to carry out scans than existing sensors.There are also other caveats:

• it is capable of working only with OLED displays and not their cheaper LED counterparts
• the thickness of the glass cannot be thicker than 0.8mm. Even though several existing smartphones already use thinner glass, but that still means that the owners will probably not be able to add screen protectors
• manufacturers will not be able to order the part in bulk until late 2017 or early in 2018.

Samsung had been rumoured to be working on a similar feature of its own for the Galaxy S8 phone but ultimately the device launched without it.

It would have been the most logical thing for Samsung since it wanted the biggest screen and smallest bezels possible, but ultimately it was obliged to move the fingerprint sensor to the back of the phone. Unfortunately, that wasn't a wise thing to do because it ended up being close to the camera.