TWO IS BETTER THAN ONE
Smooth, rapid autofocus is a crucial factor in image quality. The 40-150mm f2.8 PRO’s innovative, industry-first Dual VCM (voice coil motor) AF delivers. Separating the focusing mechanism into two lens groups controlled by individual linear drive motors makes AF performance extremely fast and, with no gears involved, nearly friction-free and incredibly quiet.
That is something entirely different than this patent. The motor described here drives the diaphragm to stop down the aperture, which is quite different than the focusing groups in a lens.
Concievably you could use the same preload motor and drive motor design to speed up focus movements, however i dont think the USM motor is the weak link in the focus chain, although i could be wrong.
