CAFC reverses BPAI in Tanaka: adding dependent claim proper in re-issue

The key text in the Tanaka decision of the CAFC, which reverses the underlying BPAI decision:

Nearly a half century ago, our predecessor court, the
Court of Customs and Patent Appeals, clearly stated that
adding dependent claims as a hedge against possible
invalidity of original claims “is a proper reason for asking
that a reissue be granted.” In re Handel, 312 F.2d 943,
946 n.2 (CCPA 1963). The basis for the reissue applica-
tion in Handel was nearly identical to that in this case.
The patentee had mistakenly failed to include narrow
claims that he had a right to claim and later sought
reissue to obtain those narrower claims without proposing
to cancel any broader claims encompassing the claims
sought to be added. The proposed reissue claims differed
from the existing claims simply by the inclusion of addi-
tional limitations.

Judge Giles S. Rich wrote the Handel decision revers-
ing the Board’s rejection of the reissue application. He
explained that the reissue claims involved subject matter
disclosed in the specification and thus were properly
directed to “the invention disclosed in the original patent.”
Id. at 944. In a footnote, Judge Rich remarked that “[t]he
term ‘inoperative’ has been construed to mean inoperative
adequately to protect the invention, which may be due to
failure of the solicitor to understand the invention.” Id. at
945 n.2 (quoting McGrady, Patent Office Practice 309 (4th
ed. 1959)). Judge Rich added that because the original
patent claims were all retained in the reissue application
the “term ‘less’ [in Handel’s reissue declaration] appears
to have been used in the sense of fewer claims than he
could properly have made, rather than in the statutory
sense of subject matter included within the claims.” Id. at
946 n.2 (emphasis in original). Thus “[t]he narrower
appealed claims are simply a hedge against possible
invalidity of the original claims should the prior use be
proved, which is a proper reason for asking that a reissue
be granted.” Id. While this court has since characterized
that view as dictum, it has not departed from it.

The CAFC rejected the BPAI ruling:

Even though the rule that adding a dependent claim
as a hedge against possible invalidity is a proper reason to
seek reissue has seemingly never been formally embodied
in a holding of this court or its predecessor, articulation of
the rule in Handel was not simply a passing observa-
tion—it was a considered explanation of the scope of the
reissue authority of the PTO in the context of a detailed
explanation of the reissue statute. Based on this court’s
adoption of that rule and its adherence to the rule in both
Muller and Hewlett-Packard, this court rejects the Board’s
contrary ruling.

AND

This court, however, has recognized that “each claim
is a separate statement of the patented invention.” Pall
Corp. v. Micron Separations, Inc., 66 F.3d 1211, 1220
(Fed. Cir. 1995). And each claim of a patent has a pur-
pose that is separate and distinct from the remaining
claims. Claims of narrower scope can be useful to clarify
the meaning of broader, independent claims under the
doctrine of claim differentiation. Phillips v. AWH Corp.,
415 F.3d 1303, 1314 (Fed. Cir. 2005). And dependent
claims are also less vulnerable to validity attacks given
their more narrow subject matter. Thus, the omission of a
narrower claim from a patent can render a patent partly
inoperative by failing to protect the disclosed invention to
the full extent allowed by law.

Of "no defect" reissue:

In addition, unlike the practice of “no
defect” reissue, Tanaka’s reissue application requested
changes to his patent in the form of a new dependent
claim. Applying for a reissue that adds only narrower
claims without amending any of the original claims is not
the same as a “no defect” reissue.

Judge Dyk dissented:

Respectfully, I dissent. I would affirm the Board’s
holding that the addition of a narrower claim in a reissue
application is not a proper basis for reissue under 35
U.S.C. § 251 if the application still contains all of the
original patent claims.

Of Handel, Judge Dyk stated:

On appeal, our predecessor court made clear
that its “function [was] to pass only on such grounds of
rejection as [had] not been reversed by the [Board].” Id.
at 948 Thus, whether the addition of narrower claims
was a proper grounds for reissue was “clearly out of the
case.” Id. at 946. The court stated explicitly that the
“sole issue in the case [was] whether the [reissue] claims
[were] ‘for the invention disclosed in the original patent,’
as required by 35 U.S.C. § 251.” Id. at 944. Though the
court stated in a footnote that reissue is proper when the
only change to the original patent is the addition of nar-
rower claims as “a hedge against possible invalidity,” it
did not squarely address the issue. See id. at 945 n.2.