Comment Re:All Patents Terminate (Score 1) 686
That's not true. You can have multiple concurrent patents on the same thing that all expire on the same day. You can also have improvement patents or patents on different ways of doing things. But then it's not "the same thing".
You can have multiple patents which cover the same thing, expiring on different dates, some even applied for after the expiration of the previous one. This is not supposed to happen, but it does.
This also is not true. Any small difference between the prior art and the patent means that the prior art does not anticipate the patent. Any small difference between the accused infringing device and the patent claims means that the accused device does not literally infringe the claims.
However, the prior art may still teach or suggest the patent and render it obvious, and the accused device may infringe through the doctrine of equivalents if the differences are minor.
The doctrine of equivalents is applied so broadly and obviousness so narrowly that what I said is the case in practice. Particularly not once the patent is granted and has a presumption of validity in its favor.