Vivo has recently has launched world first under display fingerprint sensor in smartphones.Vivo has implemented the solution for under display fingerprint developed by Synaptics.
How does it Works?
Firstly,this sensor only works on OLED display because there are gaps between Pixels of display and this technology uses Optical Fingerprint Sensor.When the light is send beyond from the display from the gaps between pixels,it gets blocked with your fingerprints and a map is created which is then matched with map that was created during fingerprint initiliazation.
But Optical fingerprint sensor is quite slow then Capacitve sensor which is currently being used by most of the smartphones but who cares.I am damn sure that on upcoming days Apple,Samsung and other smartphones companies are going to copy this technology.