Qualcomm has announced its 3D Sonic In-Screen Fingerprint sensor at its Snapdragon Summit 2018. It is a bit of a re-branding of the Qualcomm Sense ID ultrasonic fingerprint reader we covered back in 2015. However, it seems now ready for prime time since partners will ship it in 2019 phones.
We’ll explain how it works, but to give you some context, all the commercially available in-screen fingerprint readers today work with an optical sensor. It means that when you put your finger on the area of the display right above the sensor, a light will illuminate your fingerprint to obtain a 2D image, which will then be analyzed. That’s the classic way fingerprint sensors work.
It can free up a lot of bezel space, but the main disadvantage of that technique is that it is less reliable and noticeably slower than the classic fingerprint readers. We’ve recently tested the Vivo V11 and the Huawei Mate 20 Pro, both of are among the first phones to get an in-screen fingerprint sensor.
Qualcomm’s 3D Sonic fingerprint sensor works completely differently because it uses a 3D Map of your fingerprints, including the skin pores. The ultrasonic waves can act as a Radar and map each fingerprint as satellites hovering above the Earth would map mountains and valleys. The dataset obtained could be compared to a 3D terrain mapping, from which you can find unique points that will uniquely identify an individual.
The 3D data is much more complex than a 2D print, so there are many more reference points possible, which makes this type of fingerprint reading much more secure and had to fake. For example, many 2D sensors can be fooled with a 2D imprint that was “lifted” from a flat surface. A 3D Sonic reader should be able to tell the difference, and it would be a lot of trouble to lift and reprint a 3D fingerprint.
The 3D Sonic fingerprint reader does not have the glass thickness limitations of optical readers. Because it doesn’t need to “see” the fingerprint, and because glass allows ultrasounds to go through, manufacturers can use thicker glass panels and layers in their displays. Thicker glass or display layers can be key to a stronger front glass, or higher screen performance.