As we can read in Phone Arena, it seems that Xiaomi has managed to register a patent in its name for a biometric fingerprint identification system that would work on the entire surface of the screen. This is in contrast to current implementations of fingerprint sensors, where users have to place their fingers in a defined area generally displayed by the software.
In the case of Xiaomi’s new patent, there should not be a specific area where to put the finger, but the entire screen would read the user’s fingerprint to try to validate it concerning the records in the terminal. For this, we would not stop having what would essentially be an optical sensor, but the differences lie in its construction.
In this case, between the capacitive layer and the AMOLED panel of the screen, we would also find light receivers and LED ultraviolet light emitters, which would be used to illuminate the fingerprint and thus be able to read the light reflected on it.
There would be more problems to manage, such as avoiding accidental unlocking in the pocket simply by reaching into it, but it is a rather exciting step forward.