Even before the release of iPhone X the Network had a lot of rumors that Apple will deploy a fingerprint scanner right under the screen. Later the representative of the company said that the development of this scanner was never conducted. Correctly received Apple rejected this idea, decided to find out Marcus Brownlie, releasing a video in which he compares Touch ID and screen scanner.
Chinese company Vivo introduced the first such scanner in smartphones. Manufacturer of sensor made by the company Synaptics. So far, the technology has been a weak distribution due to the fact that the producers decided to focus on facial recognition. However, this does not negate the fact that a screen scanners can be great, but for someone even more convenient alternative.
As for the comparison, Podebrady sensor in Vivo X21 failed to provide decent competition to the Touch ID. Fingerprint scanner from Apple has been faster, more accurate and generally more convenient in daily use.
Of course, the technology of the display scanners only gaining momentum. It is likely that in the foreseeable future such decisions can be at the same level with the traditional fingerprint modules, or perhaps even better.