The first commercially available phone with a fingerprint scanner embedded under the display glass will come in the first quarter of 2018.
Unfortunately, it will not be Apple or Samsung who will be the first with the technology, but instead it will be Vivo, a Chinese company that does not officially sell its phones in the United States. Still, we expect it to be first of many and other mainstream brands may follow suit if the technology works well (and that is one important 'if').
This first under-screen fingerprint scanner is developed by Synaptics with its Clear ID FS9500 chip, a small CMOS device placed below an AMOLED screen. It illuminates the finger, so that the fingerprint scanner can read the reflections of the finger scan and work its magic.