It has been rumored for some years that Apple will place the finger sensor under the panel, as a number of Android mobiles have done for even more years.
The OLED panel is mentioned in the patent, not mini-LED
Apple equipped the new iPad Air with finger unlocking from the on the button, which would also be logical for the iPhone series, but the fact that the sensor is placed under the panel refuses to die, because now a patent has revealed how Apple wants to do it.
Apple's system will be more advanced than the Android rival's way of doing it, as the iPhone is supposed to be equipped with a light technology that reads the finger more efficiently and without increasing the sizes of the components.
Apple has been working on this since 2013
Ming-Chi Kuo has previously stated that the 2023 iPhone top model will be equipped with this technology, but later Barclays analysts have claimed that this will be launched already this year.
In September 2019, Bloomberg announced that the iPhone 12 would be equipped with just this, but it did not happen.
We are not sure if this would have happened if covid had not changed the world, but the fact is that it is tricky with FaceID when you have to wear a mask, and not everyone has an Apple Watch that unlocks iPhone if FaceID detects you have a mask on you, a feature that can be tested with iOS 14.5 beta.
Sources: https://www.patentlyapple.com