CAFC addresses negative claim limitations in Inphi v. Netlist

The CAFC noted


Substantial evidence supports a finding that the specification
satisfies the written description requirement
when “the essence of the original disclosure” conveys the
necessary information—“regardless of how it” conveys
such information, and regardless of whether the disclosure’s
“words [a]re open to different interpretation[s].” In
re Wright, 866 F.2d 422, 424–25 (Fed. Cir. 1989) (citation
and internal quotation marks omitted); see also Falko-
Gunter Falkner v. Inglis, 448 F.3d 1357, 1365–66 (Fed.
Cir. 2006) (finding substantial evidence supported written
description based on “several passages in the [patentee’s]
application” and the unrebutted “testimony of [the patentee’s]
expert,” which showed that skilled artisans
would understand the invention); Novozymes A/S v.
DuPont Nutrition Biosciences APS, 723 F.3d 1336, 1346
(Fed. Cir. 2013) (discussing the metaphor from In re
Ruschig, 379 F.2d 990, 995 (1967) that a disclosure should
“provide sufficient ‘blaze marks’ to guide a reader through
the forest of disclosed possibilities toward the claimed
compound”).
Whether a patent claim satisfies the written description
requirement of 35 U.S.C. § 112, paragraph 1 depends
on whether the description “clearly allow[s] persons of
ordinary skill in the art to recognize that [the inventor]
invented what is claimed.” Vas-Cath Inc. v. Mahurkar,
935 F.2d 1555, 1562–63 (Fed. Cir. 1991) (internal quotation
marks omitted) (quoting In re Gosteli, 872 F.2d 1008,
1012 (Fed. Cir. 1989)).
[W]hatever the specific articulation, the test requires
an objective inquiry into the four corners of
the specification from the perspective of a person
of ordinary skill in the art. Based on that inquiry,
the specification must describe an invention understandable
to that skilled artisan and show that
the inventor actually invented the invention
claimed.
Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351
(Fed. Cir. 2010) (en banc).



As to negative limitations:




In particular, “[n]egative claim limitations are adequately
supported when the specification describes a
reason to exclude the relevant limitation.” Santarus, 694
F.3d at 1351.
(...)
When viewed in its proper context, Santarus simply
reflects the fact that the specification need only satisfy
the requirements of § 112, paragraph 1 as described in
this court’s existing jurisprudence, including through
compliance with MPEP § 2173.05(i) (“If alternative elements
are positively recited in the specification, they may
be explicitly excluded in the claims.”) and In re Johnson,
558 F.2d at 1018 (“It is for the inventor to decide what
bounds of protection he will seek.”).



link: http://www.cafc.uscourts.gov/sites/default/files/opinions-orders/15-1179.Opinion.11-10-2015.1.PDF