WARNER JENKINSON COMPANY, INC., PETITIONER v. HILTON
DAVIS CHEMICAL CO.
on writ of certiorari to the united states court of appeals for the
[March 3, 1997]
, with whom Justice Kennedy I join the opinion of the Court and write separately
to add a cautionary note on the rebuttable presumption the Court announces
regarding prosecution history estoppel. I address in particular the application
of the presumption in this case and others in which patent prosecution
has already been completed. The new presumption, if applied woodenly, might
in some instances unfairly discount the expectations of a patentee who
had no notice at the time of patent prosecution that such a presumption
would apply. Such a patentee would have had little incentive to insist
that the reasons for all modifications be memorialized in the file wrapper
as they were made. Years after the fact, the patentee may find it difficult
to establish an evidentiary basis that would overcome the new presumption.
The Court's opinion is sensitive to this problem, noting that "the PTO
may have relied upon a flexible rule of estoppel when deciding whether
to ask for a change" during patent prosecution. Ante, at 13, n.
Because respondent has not presented to this Court any explanation for
the addition of the lower pH limit, I concur in the decision to remand
the matter to the Federal Circuit. On remand, that court can determine--bearing
in mind the prior absence of clear rules of the game--whether suitable
reasons for including the lower pH limit were earlier offered or, if not,
whether they can now be established.