With the trend of creating smartphones with smaller and narrower bezels, it has become impractical to put sensors on the front of a smartphone. Especially the fingerprint sensor where it occupies a rather larger dimension.
As a result smartphone makers have moved the sensor to the side, or back, or even removed it entirely.
At CES 2018 in Las Vegas Convention Center, Chinese phone maker Vivo showed off the world's first smartphone with a fingerprint sensor embedded underneath the touchscreen.
The company has been working to put a fingerprint sensor underneath the screen for the last few years, but it was in 2018 that it finally made one that is ready for mass production.
Previously, VIvo in 2017 had announced that it had developed the "in-display fingerprint scanning" technology for a prototype phone. The technology uses an ultrasonic sensor and was created with support from Qualcomm.
However, the newer version of the fingerprint scanning technology is based on optics that was developed alongside Synaptics.
When a user wakes the phone, the display will show a lock screen with a blue fingerprint icon where user can put his/her finger.
Putting his/her finger on the sensor, the phone will make the display to emit lights to the finger that touches the screen. This will illuminate the fingerprint. Then the light is reflected back into an in-display fingerprint sensor to be authenticated.
The design is only compatible with OLED displays as they are transparent enough to let the sensor detect a finger above the glass.
What this means, Vivo is pioneering the way to create smartphones with no bezels, but still capable of having fingerprint scanning sensor at the front.
Initially, the in-display sensor is only located at the center-bottom. What this means, the user can only register his/her fingerprint by touching a limited place of the screen. The fingerprint scanner was also not as quick as other smartphones with a physical fingerprint sensor.
The Vivo phone that was demoed on CES 2018 does not have an official name yet.
