Canon Patent Application: Full frame mirrorless UWA

We have been waiting to see if we start to see any patent applications that suggest a full frame short registration distance optical design, and here's one patent application that may indicate something of what Canon is planning.

This is a 16-28 2.8 patent application of a full frame lens with a short backfocus of only 11.34mm.  Suggesting a full frame mirrorless with a shorter registration distance than the EF mount.

This patent application is specifically for shortening the backfocus of the element design, making it a solution for a future short backfocus mirrorless camera system.

Japan Patent Application 2018-077320