The U.S. Supreme Court reigned in the Federal Circuit’s indefiniteness standard for patent claims almost a year ago in Nautilus Inc. v. Biosig Instruments Inc.1 Recently, on April 27, 2015, the Federal Circuit revisited the issue applying the Supreme Court's new test for indefiniteness in the Nautilus case on remand from the court. The Federal Circuit's opinion demonstrates that balancing the competing interests of clarity in claim scope and the recognition that "absolute precision is unattainable" will take some time to establish.2 In the meantime, it is useful to review some of the more notable Federal Circuit decisions interpreting the Supreme Court’s new "reasonable certainty" standard to examine useful patterns that are emerging. Among other things, these decisions emphasize that the best way to survive an indefiniteness challenge when drafting claims is to use the language of the claims in the specification, provide sufficient examples, and avoid or carefully choose subjective language, "words of degree," and ambiguities in prosecution.

This is a particularly timely opportunity to review how this area of law is evolving post- Nautilus, particularly as the Supreme Court is currently being asked in the Packard v. Lee case to consider whether the Nautilus test should be applied differently in the patent office than in district courts.

By way of background, under 35 U.S.C. § 112 ¶ 2, a patent application must include a specification, as prescribed by Section 112 of the Patent Act, containing a written description of the invention and "must 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." 3 The latter requirement is often referred to as the “definiteness” requirement. It serves the dual purposes of “secur[ing] to the patentee all to which he is entitled” and of “appris[ing] the public of what is still open to them." Markman v. Westview Instruments, Inc., 517 U.S. 370, 373 (1996).

In Nautilus v. Biosig Inst., the Supreme Court considered whether the Federal Circuit’s definiteness standard of “amenable to construction” or “insolubly ambiguous” was in line with what the Patent Act requires under 35 USC § 112, ¶ 2. The court, in weighing the definite test, acknowledged the balance between the limitations of language and the notice requirement patent claims are meant to provide, and found that the Federal Circuit’s existing test “breed[s] lower court confusion for they lack the precision §112, ¶ 2 demands” and in turn leave the “courts and the patent bar at sea without a reliable compass.”

The court held that “a patent is invalid for indefiniteness if its claims, read in light of the patent’s specification and prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.” Recently, the Federal Circuit, on remand, had a second chance to evaluate the Biosig claims, this time under the Supreme Court's "reasonable certainty" standard. Echoing the Supreme Court's compass analogy, the Federal Circuit in undertaking its review stated "we may now steer by the bright star of 'reasonable certainty,' rather than the unreliable compass of 'insoluble ambiguity.'" Steering by this "bright star," the Federal Circuit once again found the disputed claim term "spaced relationship" to be sufficient to "inform those skilled in the art about the scope of the invention with reasonable certainty." This begs the question of when the new reasonable certainty standard, at least in the opinion of the Federal Circuit, will yield results that are different than its previously articulated standard.

Despite the recent outcome of Nautilus, the Federal Circuit has decided several other appeals involving indefiniteness claims under the “reasonable certainty” standard. A brief review of these cases gives an indication of how the Federal Circuit is approaching the issue and applying Nautilus, particularly when it comes to claims with subjective limitations, containing words of degree that describe the scope of the claimed invention.

In Interval Licensing v. AOL, the Federal Circuit was asked whether the claim term “unobtrusive manner that does not distract a user” is indefinite. The patent at issue in Interval Licensing is directed to an attention management system intended to occupy “the peripheral attention of a person in the vicinity of a display device.” The majority of the claims recite the phrase “unobtrusive manner that does not distract a user.” During claim construction in the federal district court, a court in the Western District of Washington found the terms in an "unobtrusive manner” and “does not distract” indefinite, and therefore invalid. On appeal, the Federal Circuit affirmed the lower court’s finding of indefiniteness.

The Federal Circuit explained that the phrase “unobtrusive manner” is a highly subjective term of degrees that on its face provides little guidance to one of ordinary skill in the art. Despite the use of the term in the specification with respect to different embodiments, the Federal Circuit found that the “hazy relationship between the claims and the written description fails to provide the clarity that the subjective claim needs.”

Upon review of the prosecution history, the Federal Circuit found that Interval’s arguments reflected considerable uncertainty about whether all the embodiments were tied to the “unobtrusive manner” language or only certain embodiments. The court concluded, therefore, that the “facially subjective claim language” had no “objective boundary” and that it failed to “inform those skilled in the art about the scope of the invention with reasonable certainly.” The Federal Circuit noted that the inclusion of examples in the specification of claim terms may overcome indefiniteness issues; however, the examples in this case did not provide an exclusive definition that one skilled in the art would understand to be the boundary of the claimed invention. The Federal Circuit explained, that if the phrase in the specification had been cast clearly as a definition, instead of merely an example, it may have provided the clarity required.

The Federal Circuit's decision in Interval provides an example of what the court will not accept. In contrast, other decisions by the Federal Circuit mark an interesting development in the boundaries of the Nautilus decision. In DDR Holdings v., for example, decided post Nautilus, the Federal Circuit was asked if the term “look and feel” in the claims is indefinite. Despite having agreed on the definition of the term during claim construction, defendant filed a post-trial motion that the claim terms “look and feel” and “visually perceptible elements” were indefinite. The motion was denied and the defendant appealed.

The Federal Circuit found that despite defendant’s attempts to couch the phrase “look and feel” as purely subjective, the evidence established that the phrase has a “sufficiently objective” meaning in the art and that the patent used that term consistent with that meaning. The Federal Circuit pointed out that the specification describes “look and feel” as including logos, colors, page layout, etc. and provides examples consistent with the established meaning of the phrase in the art. In sum, the Federal Circuit found that “look and feel” was not “facially subjective” like “unobtrusive manner.” Instead, it found the phrase to be consistent with the established meaning, and that when viewed in light of the specification and prosecution history, sufficient to inform one skilled in the art with reasonable certainty.

The Federal Circuit's decision in Lexington Luminance v. is another case that diverges from the Federal Circuit's approach in Interval concerning when examples of claimed structures in the claims or specification suffice to satisfy the indefiniteness requirement. A district court in Massachusetts found the asserted patent’s claims indefinite because they failed to narrow down the composition of a claimed substrate to a degree of substantial certainty. In Lexington, the claims recited a substrate material “selected from the group comprising group III-V, group IV, group II-VI elements and alloys of ZnO, spinel and sapphire.” This Markush group used the open ended language “comprising” rather than the closed “consisting” language. The district court held that this was indefinite because it provided for an indeterminate number of other elements to be included with the enumerated elements. The Federal Circuit vacated the district court’s decision, finding that the open ended Markush group did not per se render the claim indefinite.

In Lexington, the Federal Circuit did not address the “technical correctness” of the Markush group, instead it focused on the claims in light of the specification. The Federal Circuit found that the specification provides clear description of the substrates that form part of the claimed substrate, noting that the “intrinsic record is reasonably definite on indicating what the claim covers because the specification lays out a considerable list of exemplary substrates that correspond to the materials specified in the claim.” Indeed, the specification lists specific elements to be included in the substrate. The Federal Circuit noted that other “improper” Markush groups might not pass the definiteness test depending on what was in the record and the written description. Here, because of the list of specific examples, the Federal Circuit found that the claim in light of the specification satisfied the Supreme Court’s “reasonable certainty” test and would inform one skilled in the art as to the proper scope of the claim, despite the “imperfect usage of Markush terminology.”

In Eidos Display LLC v. AU Optronics Corp., the Federal Circuit reversed and remanded the U.S. District Court for the Eastern District of Texas’ summary judgment of indefiniteness. In Eidos, the claim at issue was directed to a method for producing an electro-optic device and recited “a contact hole for source wiring and gate wiring connection terminals.” Eidos originally proposed a construction in line with standard practice and consistent with the specification, that required “separate and distinct holes for the source wiring connection terminals and gate wiring connection terminals”. Defendants, on the other hand, argued that the plain meaning requires a shared contact hole for all connection terminals.

During Markman, the magistrate judge stated that “the Court is unable to arrive at a construction that would allow a person of ordinary skill in the art to determine what is claimed when the claim is read in light of the specification.” Accordingly, the magistrate recommended that the district court grant summary judgment on indefiniteness. The district court granted the motion and Eidos appealed. The Federal Circuit reversed, finding that Eidos’ proposed construction reflected how one skilled in the art would understand the limitation given the intrinsic record.

Specifically, the Federal Circuit found that the “intrinsic record” makes it “sufficiently clear that a person of ordinary skill in the art … would understand the limitation-at-issue to call for separate, different contact holes for the source wiring connection terminals and gate wiring connection terminals, rather than one shared contact hole.” The Federal Circuit pointed out that nothing in the voluminous specification (172 figures and 58 columns) describes how one skilled in the art would deviate from the then known industry practice. The court took notice that the specification describes only embodiments consisting of separate holes for the gate contact holes. It concluded that if the patentee wanted to deviate from the standard practice, some teaching for doing so would have been described in the specification. It therefore found the claims definite and amenable to construction.

Lastly, in Augme Tech. v. Yahoo! Inc., the Federal Circuit affirmed a finding by the district court in Northern California that the phrase “means for assembling, at said server system, said second computer readable code module” in the asserted claims was indefinite. The Federal Circuit found that the phrase “means for assembling” was a computerimplemented means-plus-function limitation and that the specification failed to disclose an algorithm that would constitute corresponding structure for performing such claimed function. The Federal Circuit held that without such an algorithm, one of skill in the art could not be reasonably certain as to the scope of the claim.

The Federal Circuit noted that an “algorithm may be expressed in any understandable terms including as a mathematical formula, in prose, or as a flow chart, or in any other manner that provides sufficient structure.” But some algorithm must be disclosed. The claim cannot merely restate the function. Augme argued that an algorithm for how a service response is formed and distributed and then then how the second code module is formed was disclosed in the specification and that even source code was disclosed. The Federal Circuit disagreed. The Federal Circuit found that the specification did not include an algorithm for how the second code module is actually assembled. It stated that “[s]imply disclosing a black box that performs the recited function is not a sufficient explanation of the algorithm required to render the means-plus-function term definite”.

While there are no guarantees, some common themes emerge from these cases that may affect whether claims are found to be indefinite.

Use the language of the claims in the specification.

First, rather than just copying the claims into the summary of the invention, be sure to use the language of the claims in drafting the patent’s detailed description. This may be especially true if one is inclined to draft claims as the final step in drafting the application. Doing this reduces the ambiguity about a phrase in the claims and points directly to the detailed portion of the specification. Simply having the term appear in the summary does no more then recite the claim element and provides no reasonable certainty or guidance, and therefore, will not provide support in opposition to an indefiniteness challenge.

Use examples.

Second, provide sufficient examples of critical claim terms and phrases in the specification. As DDR, Lexington and Eidos illustrate, even imprecise claim language, depending on the circumstances, may be saved if the disclosure identifies examples sufficient to inform one skilled in the art what the disputed phrase means.

Avoid or define subjective language where possible.

Third, consider defining subjective claim elements that are critical to the novelty of the invention. While patent attorneys never want to lock themselves into a definition, where a subjective phrase is critical to the claims, as seen in Interval, it may be wise to provide not only examples, but definitions. Also, if there is ambiguity in the claim language, avoid compounding the situation by making contradictory arguments during prosecution.

Describe more then a “black box” when using means-plus-function language in software patents.

Fourth, avoid using means-plus-function language in software patents unless providing some clear guidance in the specification, such as algorithms, flowcharts, or code. Reciting elements such as a “code generator” without” defining how exactly it “generates code” may be fatal to the claims.

These decisions and the tips learned from them emphasize that the best way to survive an indefiniteness challenge is to avoid subjective language, "words of degree," and ambiguities in the claims, make sure terms are supported by the specification and provide clear examples.