Under-screen fingerprint principle

With the popularity of smart phones, fingerprint identification technology has also been widely used. In the traditional fingerprint identification method, the fingerprint sensor is usually placed on the front or back panel of the mobile phone, but this method sometimes affects the beauty of the mobile phone. In order to solve this problem, off-screen fingerprint identification technology came into being.

Optical off-screen fingerprint identification technology is the most widely used off-screen fingerprint identification technology at present. Its principle is to use optical sensors to collect fingerprint images. When the user puts his finger on the screen, the optical sensor at the bottom of the screen will emit light, and the light will pass through the screen and shine on the user's finger. When light strikes the fingerprint, part of the light will be absorbed by the fingerprint, and the other part will be reflected back to the sensor. The sensor will generate a fingerprint image according to the intensity of the reflected light, and compare it with the fingerprint template stored in the mobile phone to determine the identity of the user.

Ultrasonic off-screen fingerprint identification technology is a new off-screen fingerprint identification technology. Its principle is to use ultrasonic sensors to collect fingerprint images. When the user puts his finger on the screen, the ultrasonic sensor will emit some high-frequency sound waves, which will pass through the screen and shine on the user's finger. When sound waves hit the fingerprint, part of the sound waves will be absorbed by the fingerprint and the other part will be reflected back to the sensor. The sensor will generate a fingerprint image according to the intensity of the reflected sound wave, and compare it with the fingerprint template stored in the mobile phone to determine the identity of the user.