Definiteness and Patent Drafting: The Nautilus Surfaces

EDITORIAL NOTE: What follows is an excerpt from the latest edition of Rules for Patent Drafting: Guidance from Federal Circuit Cases, 2017 Edition, which will be released the week of May 10, 2017. Also, the author — Joseph Root — will join Gene Quinn for a free webinar on drafting patents to withstand challenge on Wednesday, April 19, 2017, at 2pm ET. CLICK HERE to REGISTER.


The public notice function of patents lies at the heart of the definiteness requirement. The Supreme Court summed up this requirement in a 1938 decision, General Electric Co. v. Wabash Appliance Corp.:

The limits of a patent must be known for the protection of the patentee, the encouragement of the inventive genius of others, and the assurance that the subject of the patent will be dedicated ultimately to the public. The statute seeks to guard against unreasonable advantages to the patentee and disadvantages to others arising from uncertainty as to their rights. The inventor must “inform the public during the life of the patent of the limits of the monopoly asserted, so that it may be known which features may be safely used or manufactured without a license and which may not.

This language, and its accompanying rationale, remain central to any analysis of § 112(b).

The Federal Circuit revisited its definiteness analysis in a 2001 decision, Exxon Research and Engineering Co. v. U.S. This case concerned a process for converting natural gas to liquid hydrocarbon products. The synthesis gas is introduced into a slurry bubble column, where it undergoes a reaction mediated by catalytic particles suspended in liquid hydrocarbons. Critical to the case was the meaning of the term “UL” indicating liquid velocity in the column, which could be interpreted as either interstitial velocity (which takes into account impediments to flow, such as internal structures) or superficial velocity (which omits such factors). The court found it a close question, noting that a single word in the specification could have cured the ambiguity. It described the applicable analytical framework as follows:

We have not insisted that claims be plain on their face in order to avoid condemnation for indefiniteness; rather, what we have asked is that the claims be amenable to construction, however difficult that task may be. If a claim is insolubly ambiguous, and no narrowing construction can properly be adopted, we have held the claim indefinite. If the meaning of the claim is discernible, even though the task may be formidable and the conclusion may be one over which reasonable persons will disagree, we have held the claim sufficiently clear to avoid invalidity on indefiniteness grounds.

That standard held sway until 2014, when the Supreme Court handed down its decision in Nautilus, Inc. v. Biosig Instr., Inc. There, a unanimous Court rejected the Federal Circuit’s test and substituted a new formulation, asking whether the claims, “viewed in light of the specification and prosecution history, inform those skilled in the art about the scope of the invention with reasonable certainty.”

The invention under analysis concerned heart rate monitors employed on exercise machines. A claim in suit included the term “spaced relationship,” indicating a distance between the common electrode and live electrode in each electrode pair. The district court had granted summary judgment of invalidity on definiteness grounds because the term “spaced relationship” because the term did not allow a person of ordinary skill in the art to determine an appropriate spacing between the electrodes. The Federal Circuit reversed and remanded, reasoning that a reading of the specification enabled one to establish maximum and minimum spacing, and taking that evidence together with the record created during a re-examination of the patent in suit, a person of ordinary skill in the art could arrive at a functioning device by varying design parameters. Thus, the term was both “amenable to construction” and not “insolubly ambiguous.”

The Court’s rationale was not kind to the Federal Circuit:

In resolving Nautilus’ definiteness challenge, the Federal Circuit asked whether the [] patent’s claims were “amenable to construction” or “insolubly ambiguous.” Those formulations can breed lower court confusion, for they lack the precision § 112, ¶ 2 demands. It cannot be sufficient that a court can ascribe some meaning to a patent’s claims; the definiteness inquiry trains on the understanding of a skilled artisan at the time of the patent application, not that of a court viewing matters post hoc. To tolerate imprecision just short of that rendering a claim “insolubly ambiguous” would diminish the definiteness requirement’s public-notice function and foster the innovation-discouraging “zone of uncertainty,” against which this Court has warned …

But although this Court does not “micromanag[e] the Federal Circuit’s particular word choice” in applying patent-law doctrines, we must ensure that the Federal Circuit’s test is at least “probative of the essential inquiry.” Falling short in that regard, the expressions “insolubly ambiguous” and “amenable to construction” permeate the Federal Circuit’s recent decisions concerning § 112, ¶ 2’s requirement. We agree with Nautilus and its amici that such terminology can leave courts and the patent bar at sea without a reliable compass.

The Court declined to apply the new standard, remanding to allow the Federal Circuit to reconsider its decision.

On remand, the Federal Circuit took the position that while the Court had “found to be precise our ‘insolubly ambiguous’ standard,’ ” its decision had merely “modif[ied] the standard by which lower courts examine allegedly ambiguous claims.” Indeed, the section heading discussing this point is entitled “Reasonable Certainty under Nautilus II Is a Familiar Standard,” concluding, “In the wake of Nautilus II, judges have had no problem operating under the reasonable certainty standard.” The court reiterated its reversal of the trial court’s decision.

As noted above, the Supreme Court did not apply the “reasonable certainty” standard to the facts of the Biosig case. Rather, it vacated the Federal Circuit’s prior decision and remanded for further proceedings in light of the Court’s analysis.

The remand was taken up by a panel consisting of Judges Newman, Schall, and Wallach. The judges recognized that the Supreme Court had focused on two competing interests, seeking to balance the “inherent limitations of language” on one hand, against the need for sufficient precision to “afford clear notice of what is claimed.” While recognizing the mandate of a new standard, the judges also emphasized the continuity of that standard with previous cases, linking the new standard with the caveat that “the certainty which the law requires in patents is not greater than is reasonable, having regard to the subject matter,” from the 1916 decision in Minerals Separation, Ltd. v. Hyde.

The specific question before the judges was a claimed “spaced relationship” between two electrodes in the heart rate monitor described and claimed in the Biosig patent. The patent text describes the electrodes as being “spaced” without elaboration. Notwithstanding the high court’s criticism of the Federal Circuit standard, the judges applied the prior decision’s rationale verbatim:

[T]he district court is correct that the specification of the ‘753 patent does not specifically define “spaced relationship” with actual parameters, e.g., that the space between the live and common electrodes is one inch. Nevertheless, the ‘753 patent’s claim language, specification, and the figures illustrating the “spaced relationship” between the live and common electrodes are telling and provide sufficient clarity to skilled artisans as to the bounds of this disputed term. For example, on the one hand, the distance between the live electrode and the common electrode cannot be greater than the width of a user’s hands because claim 1 requires the live and common electrodes to independently detect electrical signals at two distinct points of a hand. On the other hand, it is not feasible that the distance between the live and common electrodes be infinitesimally small, effectively merging the live and common electrodes into a single electrode with one detection point. See ‘753 patent col. 3 ll. 26-31 (describing how each hand is placed over the live and common electrodes so that they are “in physical and electrical contact with both electrodes”).

It’s important to note that the opinion approvingly cites a large number of previous cases, all decided under the “obsolete” standard. Without actually saying the words, the court seems to be signaling that the definiteness world has not completely turned upside down.

Two seminal cases illustrate the techniques of analyzing definiteness in a post-Nautilus world. One case followed Nautilus and the other preceded it, but that case demonstrates what stands of the old rationale.

The first decision, Ethicon Endo-Surgery, Inc. v. Covidien, Inc., dealt with ultrasonicshears for cutting and sealing a blood vessel. The claim at issue read as follows:

An ultrasonic surgical shears comprising:

a) an ultrasonic surgical blade;

b) a clamping arm operable to open and close toward the blade;

c) a tissue pad attached to the clamping arm, wherein the blade and tissue pad define a clamping surface area so that the applied clamp force does not exceed a clamping pressure of 210 psi at the clamping surface area; and

d) means for limiting a user applied clamping force on the clamping arm creating an average predetermined clamping pressure between and including 60 psi and 210 psi on tissue disposed between the tissue pad and the blade.

The district court held the claim invalid as indefinite, based on its failure to set out “a method of measurement, the location of measurement, and the type and amount of tissue used for the measurement of clamping force[s] and clamping pressure[s].” Reversing, the court was able to point to disclosure in the specification, bolstered by testimony setting out the knowledge of physics and mechanics applied by those of skill in the art, sufficient to show that the claims showed the scope of the claims with reasonable certainty. Specifically, the court noted,

Here, the specification clearly discloses that the claimed clamping/coaptation pressures are average pressures on tissue disposed between the tissue pad and blade, and are measured when the clamping arm and blade are in a closed position. This disclosure is sufficient to inform skilled artisans as to where these average pressures should be measured — the midpoint of the tissue pad (also the midpoint of the clamping arm for the ultrasonic shears at issue here).41

The old standard clearly did not favor holdings of indefiniteness, and the current bar has been raised.   The most egregious failing of the old standard, however, was the requirement that a claim be “insolubly ambiguous” in order to be termed indefinite Where a person of ordinary skill can understand the scope of the claim, whether through express disclosure or knowledge imputed to those of skill, the claim should pass muster. This point was well illustrated in Young v. Lumenis, Inc., concerning a method of surgically removing a claw from a domestic cat. The claim required forming an incision “near the edge” of a portion of the claw, and the district court held the claim invalid based on the ambiguity of that phrase. The Federal Circuit disagreed, even though the patent had not defined what it meant by “near.” The court reasoned,

[B]ecause the term “near” describes a location on an animal, its use, as opposed to a precise numerical measurement, is not inappropriate because the size of the appendage and the amount of skin required to be incised will vary from animal to animal based on the animal’s size. Akin to the term “approximately,” a person having ordinary skill in the art would know where to make the cut; thus the use of the word “near” does not deprive one of ordinary skill from being able to ascertain where the cut should be made.

The term “near” is not indefinite, the court concluded, because it “does not depart from the ordinary and customary meaning of ‘close to or at.’ ”

The Young v. Lumenis opinion suggests that the quest for precision, implied by the definiteness requirement, has its limits. Considering the question of how precise a claim must be, the court observed that oftentimes, “scientific tests or standards are not precise.” In such cases, if “the specification points out the precision available and [is] as precise as the science allows, then the claim term is not indefinite.” That reasoning should apply equally to post-Nautilus cases.

Drafters can achieve definiteness by careful disclosure, terms can fall within the knowledge of those in the art, or claims can be held indefinite. Those choices are illustrated in the following discussion.

A clear difference between the new “reasonable clarity” standard and the Federal Circuit’s “insolubly ambiguous” formulation is that the latter calls for considerable effort in seeking out a claim construction that comports with the inventor’s manifest intent. The new standard may require the same effort, but that result does not appear guaranteed by the language itself. The entire direction of patent law toward Disclosure World suggests that definiteness will continue to be governed in large part by the meaning drawn from the patent as a whole, not the claim language standing alone.

Time is the drafter’s most precious resource, and spending any of it to define terms and root out errors of reference and grammar may seem profligate at the end of a long drafting process. But, spending the extra hour now may make all the difference later. After all your work constructing a beautiful patent application, the last thing you want to see is a rejection where the Examiner says, “You keep using that word. I do not think it means what you think it means.”



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