Patents: This has come up twice recently in discussions of software patenting, so it’s worth posting a blog entry as a note.
There’s a common misconception that a patenter does not necessarily need to enforce a patent in the courts, for it to remain valid. This isn’t true in the US at least, where there is the legal doctrine of ‘laches’, defined as follows in the Law.com dictionary:
Laches – the legal doctrine that a legal right or claim will not be enforced or allowed if a long delay in asserting the right or claim has prejudiced the adverse party (hurt the opponent) as a sort of ‘legal ambush’.
The Bohan Mathers law firm have a good paragraph explaining this:
…the patent holder has an obligation to protect and defend the rights granted under patent law. Just as permitting the public to freely cross one’s property may lead to the permanent establishment of a public right of way and the diminishment of one’s property rights, so the knowing failure to enforce one’s patent rights (one legal term for this is laches) against infringement by others may result in the forfeiture of some or all of the rights granted in a particular patent.
See also this and this page for discussion of cases where it was relevant. It seems by no means clear-cut, but the doctrine is there.