The idea is that an internal sensor would detect when a phone is in freefall before determining its distance from the ground and how quickly it's falling.
Then the system reorients the phone in the air as it falls, positioning it in such a way to minimize damage. The patent describes how this could be accomplished by moving around a counterweight inside of the phone, actuated by a can of gas.
We can't help but be reminded of Amazon's patent for a phone airbag.
We won't be seeing this in an iPhone anytime soon. Until then, we'll stick to using our conventional case.