Mechanically speaking, the Panasonic flap type aperture is the most fault free. simpler is better. Much less likely to fail, all other things being equal...which they seldom are. At the point where the light is filtered into the optical pathway, the shape of the aperture is not that critical.
I seriously doubt that anyone has a patent on any iris. Film Cameras have been utilizing a dynamic iris for a very long time. What would be left over to control in terms of a patent after that, would be just about nil, and not worth pursuing or very likely to be enforceable in terms of a patent..and unlikely to be granted as a patent. Possibly some of the parameters of a given control system for a dynamic iris. and then, challenging such a patent would not be difficult either, I suspect, as the electronic/mechanical systems/subsystems utilized would be commonplace already.
Think about it for a second. Quite unlikely that there is any patent of any kind involved at all. There is very little in the way of innovation in the idea in the first place. In my opinion it has always been glaringly obvious and I came up with that one many years ago. I'm very surprised it took this long to come about.
