https://www.cnet.com/news/samsung-galaxy-s10-to-go-ultrasonic-an-early-look-at-its-likely-qualcomm-fingerprint-reader/

I place my thumb on the display of a dummy smartphone. A tiny, imperceptible wave of pressure shoots out of the devices and maps the ridges and valleys of my finger, verifying my identity.

In an instant, another phone that's connected to the dummy flicks to life as the home page appears.