Under-display fingerprint readers are a big trend nowadays, with almost all high-end flagships using one. Even though some still prefer the reader to be on the back or on the side of the phone, there is no denying that using your thumb directly on the display to unlock your phone looks really cool. Sadly, under-display fingerprint readers can be used only for OLED panels…up until now.
Lu Weibing, Redmi’s general manager, has presented a video with a prototype smartphone that has an under-display fingerprint reader that works on LCD displays. This is the first time that such a device was presented to the general public and is a big step forward for biometric authentication. Traditional optical fingerprint readers can’t work on LCDs because of the backlight layer needed for the screen to function. That layer prevents the sensor to actually see the finger, something that is not a problem for OLED panels.
The new technology that the R&D team developed uses an infrared high-transmittance film that allows infrared light to pass through the screen and hit the sensor. There is an infrared light transmitter at the bottom of the screen that is used as the light source. For now, we don’t know if REdmi will release this year a smartphone with this tech, but an under-display fingerprint reader for LCD displays is great news and will allow this tech to reach low-to-mid range budget smartphones.