One of the most significant announcements at the show comes from phone maker Vivo and Synaptics which enables a fingerprint reader to work on a smartphone's OLED display. This means smartphones can have thinner bezels and still offer fingerprint security. Demos from the show floor proved that Vivos solution reads fingerprints through the display which can be used as a normal display.
Placement of a fingerprint sensor has been a tricky problem for smartphone makers. Some feel having it on the front makes the most sense, while others relegate the fingerprint sensor to the back, which makes for a more natural fit for where your fingers land. As more smartphone makers opf for larger and bezel-less displays, they can now give users options of a fingerprint reader and another form of authentication like Apple's Face ID on the iPhone X.
Source: The Verge