One of the current problems with DPAF sensors is that they must be read twice, once for AF information and another time for image information. This dual reading takes time and slows down how fast the sensor can normally operate.
This patent application explores ways of reading both the AF information and the image information in parallel, making the entire step much faster than reading AF than image one after another.
How this sensor does it is a bit of magic. Every embodiment uses some form of stacked sensors. On particular embodiment uses a three layer stacked sensor. The top layer is for the pixels themselves, the second layer is to add the two halfs of the pixels together for image information, and the third layer is to compute AF information and contains memory as well, necessary to do both operations at the same time. Even though it's not mentioned, this would also be "near global shutter" capable.
Something like this would be hugely useful to future EOS RF camera bodies, and it's good to see Canon investigating and researching this further.
Japan Patent Application 2018170768