Vivo X20 Play UD in-display fingerprint scanner reliability tested

Despite year after year of delays, it seems that the in-display fingerprint scanner, alternatively called a fingerprint on display (FOD), is still a goal among smartphone makers. Some are just taking a different route. Vivo, for example, used Synaptics' optical fingerprint scanner on its X20 Play UD, the first commercial phone to sport that feature. But being under the phone's screen and, therefore, subject to the same wear and tear as the display might raise some doubts and concerns over its reliability. To answer those questions, YouTube Marques Brownlee, a.k.a. MKBHD, puts that FOD to the test.

According to a recent Korean media report, there are three types of in-display fingerprint sensors currently in development. The most experimental of them uses electrical conduction and is nowhere to be found. Although years already in development, Qualcomm's ultrasonic in-display fingerprint scanner still hasn't made an appearance on retail products, perhaps owing to its production costs.

The most common type is the optical sensor, like the very late Synaptics Clear ID FS9500. It works on the same principle as all the non-display fingerprint scanners on smartphones today. Light is shone on the fingerprint and the reflected light is recorded by the sensor and compared to the securely stored fingerprint.

because of that nature, Vivo's in-display sensor pretty much works the same as, say, Apple's Touch ID though a tad slower. That also means it's subject to the same weaknesses. Water, oil, and dirt will trip it up so you'll need to wipe your finger clean first before using it. Fortunately, no amount or severity of scratches will stop it from working, though your smartphone screen won't look any better. But, yes, it also works through screen protectors, even polarized or cracked ones.

This does bode well for the future of smartphones, presuming they jump onto in-display fingerprint scanner train. But while cheaper and more accessible, optical sensors are argued to be less accurate than ultrasonic ones, but only Samsung and Apple might be able to afford to use those.