Why are there bright spots in the fingerprint recognition area when I use the in-screen fingerprint sensor to unlock my phone?

Why are there bright spots in the fingerprint recognition area when I use the in-screen fingerprint sensor to unlock my phone?

Problem:

There are bright spots in the in-screen fingerprint sensor area when the user uses their fingerprint ID to unlock the screen.

Cause:

In-screen fingerprint sensors adopt the optical fingerprint recognition technology, which is mainly based on the refraction and reflection principles of light. Therefore, as the light source, your screen needs to increase its luminance to help generate fingerprint images.