

Ask HN: Why are patent holders allowed to sue years after their patent was infringed upon? - BigCanOfTuna

It's obvious that patent holders/trolls wait until their infringed-upon patent becomes profitable before they decide to sue the companies that made it profitable. Why is this allowed to happen? Shouldn't the patent holder be responsible for defending their patent as soon as they know that it is being violated? It seems we would have less problems with patent-trolling if the prize at the end of lawsuit wasn't so big.
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cperciva
_Why is this allowed to happen?_

IANAL, but in general if you can show that a patent holder deliberately
delayed enforcing their patent, any award of damages will be reduced under the
clean hands doctrine.

That said, there are many cases where patent enforcement takes a long time for
no fault of the patent holder. If the patent holder is an individual who
doesn't have big pockets, it might take a few years before he is aware that
his patent is being infringed; he might spend a year trying to get the
infringing company to negotiate a licensing deal; he might spend a year trying
to find a law firm willing to take the case on contingency; and that law firm
might spend a year trying to negotiate and/or collecting evidence before
actually launching a lawsuit. So even without any deliberate attempts to delay
enforcement it's entirely possible for a patent to be infringed for five years
or more before a lawsuit happens.

