How to Invent and Protect Your Invention: A Guide to Patents for Scientists and Engineers

7.4 WHEN TO SUE AN INFRINGER

In patent law, there is no fixed time limit—that is, there is no statute of limitation—for filing an infringement lawsuit. Nonetheless, courts will not allow a patent owner to sue for infringement if he waited for an unreasonably long time (say four to five years) to sue because waiting so long to file suit is unfair to the infringer. Courts award compensation equivalent to the damage caused by infringers, which is typically commensurate with royalty lost due to the infringement. If an infringer does not know he is infringing and a patent holder waits years to sue, the infringer could wind up owing millions of dollars in compensation (i.e., the cost of several years' worth of royalties) because of his ignorance. Courts may disallow an infringement suit if a patent holder waited years to file it in order to obtain more compensation from the infringer. On the other hand, if intentional (i.e., willful) infringement can be proven, the patent holder may recover triple damages plus attorney fees.