Quite a few people in the tech world believed that iPhone X would have a fingerprint sensor under the display owing to the increase in screen size of the iPhone. Although, Apple did remove the home button and nearly the entire top bezel, it failed to integrate a Touch ID sensor on the iPhone X’s screen and instead went with FaceID.

Under the display fingerprint sensor. Vivo

At CES 2018, however, we witnessed the first smartphone in the world to have a fingerprint sensor under the screen. This was made by the Chinese smartphone maker Vivo and it was also shown in action live at the event.

Reports say that Vivo has partnered with Synaptics to use the latter's technology for a fingerprint reader that sits under the display. This Vivo phone sported an all-screen design and The Verge was able to test Synaptics’s Clear ID fingerprint sensor in a hands-on. So how does it work?

According to a report by BGR, Vivo has used an ultrasonic sensor beneath the phone's display. Once pressure is applied on the screen at the exact spot where required ultrasonic signals travel through the OLED screen to create a 3D map of the fingerprint under the display. Since this process uses capacitive sensors, wet fingers won't be able to unlock the device. The location of the sensor is in the same spot that most front-facing physical fingerprint scanners are located.

The Verge claims that the sensor works just as intended like a normal fingerprint reader while registering a new fingerprint or unlocking the device. They also claimed that the sensor was slower than a regular standalone sensor, but over time the technology has the scope to improve.

Synaptics' Clear ID and its piece of tech works only alongside OLED screens, wherein it uses the gaps between the pixels for scanning the fingerprint. Though it's not clear when the device will be getting a launch or exactly how much it’ll cost, the main thing is that the Clear ID technology works. Alex Feng, Vivo's Senior VP said that the phone would be ready for mass production by early 2018.

Security of this authentication would be at the same level as current fingerprint scanners operating on devices such as the Pixel 2 or the OnePlus 5T according to a Synaptics' previous press message.