Appeal No. 2004-0659
Application No. 09/111,978
of all that is embraced in that difference”). There are some cases,
however, where the amendment cannot reasonably be viewed as
surrendering a particular equivalent. The equivalent may have been
unforeseeable at the time of the application; the rationale underlying the
amendment may bear no more than a tangential relation to the equivalent
in question; or there may be some other reason suggesting that the
patentee could not reasonably be expected to have described the
insubstantial substitute in question. In those cases the patentee can
overcome the presumption that prosecution history estoppel bars a finding
of equivalence (emphasis added).
***
When the patentee has chosen to narrow a claim, courts may presume the
amended text was composed with awareness of this rule and that the
territory surrendered is not an equivalent of the territory claimed. In those
instances, however, the patentee still might rebut the presumption that
estoppel bars a claim of equivalence. The patentee must show that at the
time of the amendment one skilled in the art could not reasonably be
expected to have drafted a claim that would have literally encompassed
the alleged equivalent (emphasis added).
The same policy considerations that prevent a patentee from urging equivalents
within what the Supreme Court refers to as “surrendered territory” should prima facie
prohibit the patentee from being able to claim subject matter within the surrendered
territory in reissue. Accordingly, the “surrendered subject matter” that may not be
recaptured through reissue should be presumed to include subject matter broader than the
patent claims in a manner directly related to (1) limitations added to the claims by
amendment (either by amending an existing claim or canceling a claim and replacing it
with a new claim with that limitation) to overcome a patentability rejection and (2)
limitations argued to overcome a patentability rejection without amendment of a claim.
These presumptions are believed to place practical and workable burdens on examiners
and applicants.
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