The first smartphone with a fingerprint scanner was introduced a way back with the launch of iPhone 5s. Later, we saw Other OEM’s brought to their Smartphones and still we are using the physical fingerprint scanners.
When we talk about under Display Fingerprint Scanner. Vivo was the First brand to introduce IN-Display Fingerprint Scanner with Vivo X20 Plus UD back in 2018. In the past few years the IN-Display fingerprint scanners have improved a lot and they have became much more fast, secure and have better accuracy compared to earlier.
How an IN-Display fingerprint works?
let us know how do these IN- Screen / under Display Fingerprint implementation has two methods. One is Optical and the other is Ultrasonic Fingerprint Scanner. Optical Fingerprint scanners use a sensor or camera placed under the Screen.
The Optical sensor illuminates bright infrared light around the scanner to capture the image of your finger with a Camera placed under the screen and stores the image of it.
In simple words, Optical sensor uses light to capture a image of your Fingerprint and stores the images When you try to unlock the device and if it matches with the image captured it unlocks the device.
On the Other hand, Ultrasonic fingerprint scanners use ultrasonic sound waves instead of light to capture a 3D image. The Ultra Sonic Scanner, way more accurate and secure compared to optical fingerprint scanners. The biggest downside of it is it works only with OLED and AMOLED Screens.
Why do they work only with OLED and AMOLED Screens?
In-Display Fingerprint scanners illuminate light to capture the image of your finger which is possible only on OLED and AMOLED Screens.
On OLED and AMOLED it is easy for the Fingerprint sensor to capture the image of your finger. As OLEDs and AMOLED don’t need a backlight that allows the light from the sensor to pass through the screen.
LCD screens require an additional backlight placed under the screen because the LCD panels aren’t bright enough. This extra layer stopping the Optical sensor to capture the image of your fingerprint.
Redmi said they found a solution for implementation of IN Display Fingerprint on LCD screen and they even showcased a prototype of a smartphone with LCD display and Under Display Fingerprint Scanner.
