There are two types of mainstream screen fingerprinting today: optical and ultrasonic. The optical type is led by Huiding Technology, and the ultrasonic wave is driven by Qualcomm.
Huiding Technology's fingerprint recognition sensor illuminates the fingerprint through the light of the AMOLED panel, then passes through the returned light to the CIS under the screen, and then analyzes the returned light, and combines the software algorithm to realize fingerprint recognition. However, when the screen brightness is insufficient or there is other display image interference in the fingerprint area, the fingerprint recognition will be deviated. In the state of completely black screen, to unlock with a fingerprint, you need to wake up the screen first, then unlock it, and the optical technology has not yet been mass-produced.
Compared to optical fingerprinting, ultrasonic signals have better penetrability and can also reduce finger dirt, grease and sweat interference, even in water. Fingerprint recognition under the ultrasonic screen is active sensing, and the power consumption is relatively high. If it is to maintain a continuous working state, the power consumption will be higher. Applying ultrasonic fingerprint recognition to the screen requires penetration of a higher thickness because the LCD panel requires backlighting, the module thickness is thicker, and the penetration of the ultrasonic signal is limited. Currently, this technology can only be used on OLED screens.