Indefiniteness finds statutory basis in 35 U.S.C. § 112 (b), which states that a “…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.” This statutory basis is fleshed out by precedential court decisions. For example, courts have said that the statutory requirement of particularity and distinctness is met only when claims clearly distinguish what is claimed from what went before in the art, and clearly circumscribe what is foreclosed from future enterprise.

Because an issued patent’s validity may be challenged based on the definiteness or indefiniteness of the issued claims, indefiniteness must be avoided by drafting attorneys and agents, considered by patent valuators, and discovered by patent litigators.

In this regard, on August 28, 2015, in Dow Chemical Co. v. Nova Chemicals Corp., 803 F.3d 620 (2015) (“Dow II”), the Federal Circuit overturned an earlier decision it had made January 24, 2012, regarding indefiniteness. In its earlier decision, the Federal Circuit cites to Enzo Biochem, Inc., and stated that indefiniteness does not require exactness, but allows for some experimentation to resolve the meaning of claim terms. (See, Enzo Biochem, Inc. v. Applera Corp., 599 F.3d 1325, 1336 (Fed. Cir. 2010), cert. denied, 131 S. Ct. 3020 (2011)). Although Dow’s disclosure did not disclose any stress-strain curves, and did not specify exactly how to calculate a slope, expert testimony was received, indicating that a person skilled in the art could calculate the slope of the SHC with a little experimentation. Thus, the claims were not held to be indefinite. As stated above, Dow II overturned this earlier decision based on the interim decision by the Supreme Court in Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. ___, 134 S. Ct. 2120 (2014), which changed the standard for indefiniteness.

The previous standard for indefiniteness stated that claims should be “…amenable to construction, however difficult that task may be. If a claim is insolubly ambiguous, and no narrowing construction can properly be adopted,…the claim [is] indefinite.” Exxon Research & Engineering Co. v. United States, 265 F.3d 1371, 1375 (Fed.Cir.2001). The Nautilus standard states that “…a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.” Nautilus, 134 S.Ct. at 2124. Under the old standard, the Federal Circuit determined Dow Chem.’s claims to be definite; however, under the new standard, Dow Chem.’s claims were found to be indefinite. Such a result seems to suggest that the newer standard constitutes a higher degree of scrutiny than the old standard, and therefore necessitated the invalidating of Dow Chem.’s claims.

Despite the appearance of the higher degree of scrutiny, in a non-precedential case, the Federal Circuit seems to indicate the exact opposite. The case is Koninklijke Philips N.V. v. Zoll Medical Corp., 2014-1764, 2014-1791 (Fed. Cir. Jul. 28, 2016). At the district court level, a jury instruction was given prior to the Nautilus decision, reciting the “insolubly ambiguous” standard as the standard for determining definite or indefinite claims. Under those instructions, the jury found the claims to be definite and awarded damages to Zoll Medical Corp. On appeal, the Federal Circuit said the following with respect to whether the now outdated instructions affected prejudice towards Phillips, the appellant:

“We conclude that it did. While we have not clarified the relationship between “insolubly ambiguous” and “reasonably certain, “ it must be admitted that the “insolubly ambiguous” standard is a harder threshold to meet than the post-Nautilus standard. Thus, if the jury actually applied the “insolubly ambiguous” standard, then it would be fair to conclude that the jury instructions prejudiced Philips, especially in light of the extensive case on indefiniteness that Philips presented-even though not sufficient to merit JMOL.” (Emphasis added).

Albeit in dicta in a non-precedential case, the Federal Circuit indicates that the new, post-Nautilus standard is a lower threshold for indefiniteness than the “insolubly ambiguous” standard. Due to the diverging indications given in Dow II and Koninklijke Philips, one must ask, ‘how certain is the reasonably certain standard that Nautilus sets forth?’ It appears that there is still room for clarification from the Federal Circuit. However, since Dow II first indicated that the Nautilus standard may be a higher threshold, cases decided after Dow II may be a good litmus for determining what we actually do know about indefiniteness.

The following is a brief summary of what we do know:

-The plain meaning of a term may lend credence to the definiteness of claims. Cioffi v. Google, Inc., 2015-1194, non-precedential, citing Ancora Techs., Inc., v. Apple, Inc., 744 F.3d 732 (Fed. Cir. 2014); see also, SimpleAir, Inc. v. Sony Ericsson Mobile Communications AB, 118 U.S.P.Q.2d 1451, 820 F.3d 419 (Fed. Cir. 2016).

-One cannot have both apparatus and method or functional language in one claim unless the apparatus claim is clearly limited to an apparatus having the recited structure and capable of performing the recited functions. UltimatePointer, L.L.C. v. Nintendo Co., Ltd., 118 U.S.P.Q.2d 1125, 816 F.3d 816 (Cir. 2016).

-If a claim term has no generally recognized meaning, it may be construed under §112, sixth paragraph, and is likely indefinite if its language “…might mean several different things and no informed and confident choice is available among the contending definitions.” Media Rights Technologies, Inc. v. Capital One Financial Corporation, 116 U.S.P.Q.2d 1144, 800 F.3d 1366 (Fed. Cir. 2015).

-Terms of degree may be scrutinized more heavily under the post-Nautilus standard as compared to the “insolubly ambiguous” standard. Liberty Ammunition, Inc. v. United States, 2015-5057, 2015-5061 (Fed. Cir. 2016) (citing Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364, 1370-71 (Fed. Cir. 2014), cert, denied, 136 S.Ct. 59 (2015)).

-Factual determinations used to reach the ultimate determination of indefiniteness are reviewed for clear error. Icon Health & Fitness, Inc. v. Polar Electro Oy, 2015-1891, 2016-1166 (Fed. Cir. 2016) (citing Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831, 842 (2015)). In this case, claims are upheld as invalid for indefiniteness after hearing expert testimony and extrinsic evidence. For an example of claims that are upheld as definite after hearing expert testimony and extrinsic evidence, see Akzo Nobel Coatings, Inc. v. Dow Chem. Co., 811 F.3d 1334 (Fed. Cir. 2016).