Functional Claim Language & Indefiniteness, Sometimes Different Sides of the Same Coin... Someti

Two recent precedential decisions out of the Court of Appeals for the Federal Circuit provide interesting instruction on functional claim language and its potential to render claims indefinite under §112(b). Many times, functional claim language can provide greater breadth than structural limitations. Patent stakeholders often consider how to cover an invention in its broadest sense. Still, how broad is too broad?

“Features of an apparatus may be recited either structurally or functionally. In re Schreiber, 128 F.3d 1473, 1478, 44 USPQ2d 1429, 1432 (Fed. Cir. 1997)” as stated in the Manual of Patent Examining and Procedure §2114; see also MPEP 2173.05(g). There are limits to the use of functional claim language. (This is especially true since the Court of Appeals sitting en banc recently removed the presumption against interpreting claims as means-plus-function where the term “means” or “step for” is not included in the claims in Williamson v. Citrix in 2015.). This fall, the court considered another dark side to functional claim language – its potential to render the claims meaningless or indefinite under §112(b). Subsection (b) requires that “[t]he specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.” (2011).

When practitioners claim elements “too” functionally, e.g., such that the claims when “read in light of the specification delineating the patent, and the prosecution history, [the claim] fail[s] to inform, with reasonable certainty, those skilled in the art about the scope of the invention,” the claims are said to be indefinite. BASF Corp. v. Johnson Matthey, Inc. Case No.: 2016-1770 (Fed. Cir. Nov. 20, 2017). at 8 quoting Nautilus, Inc. v. Biosig Instruments. The invention in BASF pertained to a catalytic converter with dual coatings for a two-stage reaction. The claim language referred to the material composition of the surface coatings as having a “composition… effective to catalyze…” rather than reciting specific material compositions. Id. at 9. The question was whether this language would have given an ordinary artisan enough information to understand what compositions were covered?

The panel reasoned that the District Court of Delaware erred in finding that the functional character of the claim language necessarily rendered the claims indefinite; instead the inquiry is context-specific. BASF supra. Next, the panel indicated that the fact that the claims left some detail as to execution out was not dispositive; the panel clarified that the claims need not provide every detail because the standard for §112 is from the perspective of an ordinary artisan, who may reasonably be able to compensate. Id. 10-11. The specification can, of course, be used to supplement the claims and in this instance the specification cited specific examples, which were also helpful on §112. Id. 10-11.

Encouragingly, the panel clarified that breadth, in and of itself, is not synonymous with indefiniteness. Id. 10-11. The accused infringer’s expert testified that the claim language was so vague that “a practically limitless number of materials” could have been used. Id. The panel instructs (however) that “the inference of indefiniteness simply from the scope finding is legally incorrect; ‘breadth is not indefiniteness.’ Id. quoting SmithKline Beecham Corp. v. Apotex Corp.

In MasterMine Software, Inc. v. Microsoft Corp., the Court of Appeals panel affirmed the District Court of Minnesota’s claim construction but reversed the lower court’s findings of indefiniteness. Case No.: 2016-2465 (Fed. Cir. Oct. 30, 2017). The invention in MasterMine involved a data management tool that the district court found indefinite for its use of “method elements” with system claims. Id. at 11. However, the panel instructed that the mere use of functional limitations with apparatus claims does not render the claims indefinite.

Though claim 8 includes active verbs—presents, receives, and generates—these verbs represent permissible functional language used to describe capabilities of the “reporting module.” Like the claims in MEC, HTC, and UltimatePointer, the claims at issue here merely claim that the system “posses[es] the recited structure [which is] capable of performing the recited functions.” MEC 520 F.3d at 1375.

Id. at 11-16. In this case, infringement could still be clearly detected despite the unconventional claim format because the recited function was tied to structure in the specification. Id. at 16-17.

Accordingly, there is nothing inherently wrong with functional claim terms. BASF and MasterMine represent two instances where functional claim language is a different coin entirely from indefiniteness and though it is not always true, the Court of Appeals endorses functional claim language with some reasonable restraints.