Sony Discloses PDAF Usable up to the Array Edges

Sony patent application US20180077372 "Solid-state imaging element and driving method therefor, and electronic apparatus" by Hiroaki Ishiwata proposes keeping the TG shape constant even though the PDAF diodes ratio changes across the array.

In interchangeable lens cameras, "if lenses having different F-values are used, there is a possibility that the light-collecting spot S may be deviated from the center of the pixel. In this case, in order to set the light-collecting spot S in the boundary between the phase-difference pixel A and the phase-difference pixel B, it is necessary to set the light-receiving surfaces of the phase-difference pixel A and the phase-difference pixel B to have a different size. The light-collecting spot position is changed depending on an image height, and hence it is necessary to change, depending on the arrangement position of the pixels in the solid-state imaging element, the size ratio between the phase-difference pixels A and B in that pixel."