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Wealth of Ideas, June 2004
In the world of patent infringement lawsuits, one defense
often raised by the defendant is “laches.”
Although it is frequently mentioned in conjunction with
a similar defense, “estoppel,” and although
the two are related, laches is not synonymous with estoppel.
Laches, from the Old French, means slackness or negligence
– a “sin of omission.” In intellectual
property law, it is the unexcused failure of a patentee
to take action in a timely manner against a patent infringer.
Why does it matter when the patentee brings suit against
an alleged infringer? Because an excessive delay may
put the defendant at a disadvantage: key witnesses may
be no longer available or memories may have dimmed;
important documents may be long gone. When laches is
found, the patentee is barred from collecting damages
accruing prior to the filing of the suit, but is still
able to obtain an injunction barring the defendant from
further infringement of the patents-in-suit.
Once the laches defense has been raised, the plaintiff
may still offer evidence that the delay either was reasonable
or not prejudicial to the defendant. Ultimately, the
burden of proving laches rests with the defendant, who
must prove that there was an unreasonable delay in bringing
suit and that this delay prejudiced the defense. However,
a rebuttable presumption of laches arises when the patentee
waits more than six years from the time when he or she
discovered (or reasonably should have discovered) the
infringement to file a lawsuit.
The moral of the story: If you sit on your rights for
too long, you may forfeit them.
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