https://youtu.be/zAp7nhUUOJE

http://www.iphonehacks.com/2017/06/qualcomm-vivo-demo-smartphone-display-fingerprint-scanner.html

At Mobile World Congress Shanghai 2017, Chinese OEM Vivo demonstrated the world’s first smartphone featuring a fingerprint scanner located under the display. The company partnered with Qualcomm to showcase the latter’s Fingerprint Sensor for Display technology.

A successor to Qualcomm’s Sense ID fingerprint technology, the Fingerprint Sensor for Display can be placed under an OLED display having a thickness of up to 1200um. Unlike traditional fingerprint scanners used in existing smartphones, Qualcomm’s latest fingerprint sensor makes use of ultrasound waves. This means that the scanner will work under water and with wet fingers as well. Additionally, Qualcomm says the fingerprint scanner can also be used to measure one’s heart beat and blood flow levels.