Goodix Under-Display Fingerprint Sensor

Forbes publishes an article "Meet The Company Behind The In-Display Fingerprint Sensors In OnePlus, Huawei, Vivo And Redmi Phones" talking about recent history of development of under-display optical fingerprint sensor, the market that has started from Synaptics but now controlled by China-based Goodix:

"Goodix wasn't the first to succeed in placing a fully functional fingerprint scanner underneath the display... After a year of fine-tuning, [Synaptics] Clear ID was officially unveiled in a Vivo prototype at the Consumer Electronics Show in January of 2018, helping Vivo grab an impressive share of headlines.

Soon after, Vivo switched over to Goodix's in-display solution for its next release, the Vivo Nex, and the improved performance was immediately noticeable.

Today, it'd be easier to name phones that don't use Goodix's in-display scanners, as Huawei, Xiaomi, Oppo, Meizu, Lenovo and OnePlus have all joined Vivo in using Goodix's scanner tech. This near monopoly of the market -- Samsung is the only brand using an in-display scanner that isn't made by Goodix -- has brought in significant revenue: Goodix made 3.8 billion yuan ($535.8 million) in revenue in 2018, of which 3 billion ($434.5 million) came from the fingerprint scanner business.

"We have 400 engineers, constantly working on our sensors from a hardware and software perspective," [Goodix's VP R&D, Carson] Ye says. "This includes fine-tuning algorithms, improving sensor light sensitivity, and things of that nature."

Here is another Goodix module taken out of the latest Xiaomi Redmi K20 phone: