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Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.
The CAFC found that first question in a prosecution history estoppel inquiry
is whether an amendment filed in the Patent and Trademark Office has
narrowed the literal scope of a claim. If the amendment was not narrowing,
then prosecution history estoppel does not apply.
But if the accused infringer establishes that the amendment was a narrowing
one, then the second question is whether the reason for that amendment was a
substantial one relating to patentability. When the prosecution history
record reveals no reason for the narrowing amendment, the patentee must show
that the reason for the amendment was not one relating to patentability if
it is to rebut that presumption and that showing is restricted to the
evidence in the prosecution history record. If the patentee successfully
establishes that the amendment was not for a reason of patentability, then
prosecution history estoppel does not apply.
If, however, the court determines that a narrowing amendment has been made
for a substantial reason relating to patentability whether based on a reason
reflected in the prosecution history record or on the patentee's failure to
overcome the Warner-Jenkinson presumption, then the third question is the
scope of the subject matter surrendered by the narrowing amendment. The
presumption is that the patentee has surrendered all territory between the
original claim limitation and the amended claim limitation. The patentee may
rebut that presumption by demonstrating that it did not surrender the
particular equivalent in question. Finally, if the patentee fails to rebut
that presumption, then prosecution history estoppel bars the patentee from
relying on the doctrine of equivalents for the accused element. If the
patentee successfully rebuts the presumption, then prosecution history
estoppel does not apply and the question whether the accused element is in
fact equivalent to the limitation at issue is reached on the merits.
In a concurring opinion, Judge Rader pointed out that, at the pace of these
changes in fundamental patent law, the noble objective of bringing more
certainty to the doctrine of equivalents nonetheless is likely to influence
both the patent acquisition and enforcement processes in unpredictable ways.
Judge Newman concurred with the decision to remand the case to determine the
rebuttal issue of unforeseeability, but thought the majority opinion placed
new and costly burdens on inventors.
For more patent information, see
http://www.patentcribsheet.com/Cases/festo3.html.
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This posting contains educational information for lawyers directly
impacting patent preparation and prosecution. It does not constitute legal
advice, nor does it create or constitute any attorney-client relationship.
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