Isn't that patent for Nikon 1 lenses - ie the little digital mirrorless thing, as already mentioned? Very small image circle, and no mirror pushing the lens away from the image plane. Despite what Ken Rockwell says (why would anybody use him as a reference?), there is a problem (challenge) created by the throat diameter in combination with the minimum possible distance between the image plane and the rear vertex (last piece of glass in the lens), so when you look at a very fast lens don't simply consider the throat diameter, but also how close it can get to the image plane. That f/0.9 Nikon was for the rangefinder, not the SLR, wasn't it?
The f/0.7 lens used for Barry Lyndon had a very small rear clearance and therefore had to be used on a modified rackover Mitchell, didn't it?
Best,
Helen