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Chill out: Numerical claim terms properly limited by industry standards

The US Court of Appeals for the Federal Circuit affirmed a noninfringement finding, concluding that a claim limitation reciting a pH range having only a lower limit referred to pH measured at standard temperature in the art. The Court also found that prosecution history estoppel and the disclosure-dedication rule foreclosed reliance on the doctrine of equivalents to capture a pH below the express lower limit. Actelion Pharms. Ltd. v. Mylan Pharms. Inc., Case No. 24-1641 (Fed. Cir. May 13, 2026) (Reyna, Taranto, Stoll, JJ.)

Actelion owns patents covering lyophilized epoprostenol formulations used to treat cardiovascular disease. Epoprostenol is unstable in water because acidic conditions catalyze its degradation. The patents sought to improve stability by manufacturing highly basic bulk solutions, thereby producing freeze-dried formulations that remained stable after reconstitution in typical intravenous fluid. The asserted claims recite bulk solutions having a pH “of 13 or higher” or “greater than 13.”

Mylan sought approval to market a generic version of Actelion’s Veletri® product and was sued under 35 U.S.C. § 271(e)(2). The district court construed “a pH of 13 or higher” to mean “a pH of 12.98 or higher.”

It was undisputed that Mylan’s bulk solution measured below a pH of 12.98 at standard temperature (25±2°C). Actelion nevertheless contended that infringement existed because the solution exceeded pH 13 at lower temperatures during refrigerated manufacturing.

The district court disagreed, finding that the claim term “a pH of 13 or higher” referred to a pH measured at a temperature standard in the field, and that therefore Mylan did not literally infringe. The district court further ruled that Actelion was barred from asserting and had not proved infringement under the doctrine of equivalents. Actelion appealed.

The Federal Circuit agreed with the district court that a person of ordinary skill would interpret the claimed pH values as measurements taken at standard temperature, absent an express indication otherwise. Although the claims did not specify measurement conditions, the specification consistently treated pH values as standard-temperature measurements. The Court emphasized that the specification compared results across pH levels without suggesting temperature-dependent variation and described an “alkaline environment” as “pH > 7,” a statement accurate only at standard temperature.

The Federal Circuit found that extrinsic evidence reinforced that understanding. The United States Pharmacopeia and expert testimony established that, in pharmaceutical formulations, pH is ordinarily measured at 25±2°C unless otherwise specified. The Court found no clear error in the district court’s factual findings on industry practice.

Because Mylan’s product failed to meet the pH limitation under that standard, the Federal Circuit affirmed the finding of no literal infringement.

The Federal Circuit also rejected Actelion’s doctrine of equivalents theory. During prosecution, Actelion amended the claims from “greater than 12” to “a pH of 13 or higher” after the examiner recognized unexpected results at pH 13 but not at pH 12. The Court found that this narrowing amendment gave rise to prosecution history estoppel, barring Actelion from recapturing lower pH values through equivalence.

Separately, the Federal Circuit applied the disclosure-dedication rule. The patents [...]

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Appellate deference: Reinforcing limits on reweighing evidence

Clarifying the proper scope of appellate review, the US Court of Appeals for the Federal Circuit affirmed an International Trade Commission final determination in full. The Court upheld the scope of the exclusion of only certain accused products and permitted importation of redesigned versions, concluding that the Commission correctly viewed the evidence and claim terms. Bissell, Inc. v. ITC, Case No. 24-1509 (Fed. Cir. May 11, 2026) (Moore, Taranto, Stoll, JJ.)

Bissell initiated a Section 337 investigation alleging that Tineco Intelligent imported wet/dry surface-cleaning devices that infringed Bissell’s patents. Following an evidentiary hearing, the administrative law judge (ALJ) found infringement of Tineco’s original products and recommended exclusion but concluded that Tineco’s redesigned products did not infringe and therefore fell outside the scope of relief.

The Commission affirmed the ALJ’s determination, which resulted in a limited exclusion order directed to the infringing products only. Both parties appealed.

Bissell challenged the finding that Tineco’s redesigned products did not literally infringe a limitation requiring that “the battery charging circuit is disabled” during the “self-cleaning mode . . . and remains disabled during the . . . cleanout cycle.” Tineco modified its products so that some battery charging did occur during a “self-cleaning mode,” but battery charging was disabled for most of the cleaning cycle. Before the ALJ, Bissell’s expert opined that infringement of this claim essentially only required a period in which self-cleaning occurred and while the battery charger was disabled. The ALJ rejected Bissell’s theory, determining that the claim required the battery charger to “remain[] disabled during the . . . cleanout cycle.”

According to Bissell, the ALJ’s conclusion amounted to improper claim construction. The Federal Circuit disagreed, finding that the ALJ had merely applied the plain and ordinary meaning of the claim term. As Bissell had not disputed that the ALJ’s findings were supported by substantial evidence, the Federal Circuit affirmed these findings.

Tineco cross-appealed the ALJ’s determination that Bissell’s domestic industry products satisfied the disabled battery limitation. According to Tineco, the evidence was inadequate to support the ALJ’s determination because the source code that Bissell’s expert relied on was never produced during the Commission trial.

The Federal Circuit found that Bissell’s expert testimony was sufficient under Federal Rule of Evidence 703, which permits experts to rely on facts or data they have been made aware of or personally observed, even if those materials are not themselves admissible, as long as they are of a type reasonably relied upon in the field. The Court emphasized that neither party disputed that experts in this context routinely rely on source code to assess infringement. The Court further concluded that substantial evidence supported the ALJ’s determination, highlighting that:

  • The source code had been produced during discovery.
  • The expert’s opinions were not conclusory.
  • Tineco did not meaningfully test the testimony through cross-examination or offer competing expert analysis.
  • The ALJ’s findings were independently corroborated by a Bissell internal document admitted at trial.

Practice note: Where the Commission uses the “face of the claim to [...]

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Corresponding disclosed structure? Only what’s necessary to perform a recited function

The US Court of Appeals for the Federal Circuit held that the disclosure of an added function in the specification of a patent should not affect the structure necessary to meet the recited function in a Section 112(f) claim element. Gramm v. Deere & Co., Case No. 24-1598 (Fed. Cir. Mar. 11, 2026) (Lourie, Reyna, Cunningham, JJ.)

Richard Gramm exclusively licensed Reaper Solutions rights to a patent directed to an apparatus for keeping the header of a crop harvester at a certain height above the ground as the harvester moves across a field. Gramm and Reaper sued Deere & Co., alleging that specific Deere header sensor kits infringed the patent. Deere challenged the validity of the patent in a partially successful inter partes review (IPR) proceeding, leaving one independent claim and some of the dependent claims asserted.

In connection with claim construction during the IPR proceeding, Reaper and Deere disputed the meaning of “control means” in the independent claim. At issue was whether the specification’s discussion of the “head controller 20” was sufficiently definite corresponding disclosed structure for the (§112(f)) means-plus-function claim element to satisfy the definiteness requirement of §112 (b). The function of the claimed “head controller” was to provide electrical control signals to another feature in the claimed apparatus to control the lateral position of the corn header and its height above the ground or soil. Deere argued that “head controller 20” was not sufficiently definite since it amounted to a general-purpose computer or processor, thus requiring disclosure of code or an algorithm to avoid being indefinite.

In 1997, the patent’s priority date, there were only three commercially available head controllers used in Deere combines: Dial-A-Matic Versions #1, #2, and #3. Deere argued that only Versions #2 and #3 could constitute corresponding structure for the “head controller 20,” as only those versions could control both header height and lateral position. Because Versions #2 and #3 used microprocessors to control header height, Deere argued that the patent specification was required to disclose an algorithm for performing the claimed function. In the alternative, Deere argued that the district court should hold Reaper to its argument in the IPR proceeding that the corresponding disclosed structure was the specific controller incorporated into Deere’s Dial-A-Matic Version #1, which “controlled header height through a series of diodes, switches and integrated circuits rather than a microprocessor.”

The district court found the independent claim indefinite and reasoned that the specification’s reference to Dial-A-Matic Versions #2 and #3 triggered the need for a disclosure of a general-purpose computer or microprocessor that the patent failed to satisfy. The district court accepted Deere’s argument that the specification did not disclose Dial-A-Matic Version #1 as a corresponding structure because it could not perform the function of controlling the lateral position of the corn header. Reaper appealed.

The Federal Circuit agreed with Reaper that the district court erred by identifying a corresponding structure for “control means” beyond what was necessary to perform the claimed function, leading the district court to incorrectly [...]

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Separately recited structures must be separately present in accused device

The US Court of Appeals for the Federal Circuit explained (again) that when a claim separately recites multiple structural limitations, infringement requires separate corresponding structures. A single component that sequentially or multifunctionally performs the claimed functions is not enough. Magnolia Medical Technologies, Inc. v. Kurin, Inc., Case No. 24-2001 (Fed. Cir. Mar. 6, 2026) (Lourie, Hughes, Freeman, JJ.)

Magnolia Medical sued Kurin for infringement of two patents directed to devices designed to reduce contamination of blood samples by skin microbes during venipuncture. The claimed devices divert the initial portion of blood, which is most susceptible to contamination, into a separate reservoir before collecting the remainder of the sample. Kurin manufactures the Kurin Lock, which separates the initial blood sample from the remaining sample using a porous plug. That plug initially functions as a vent, allowing air to escape, and then expands as it absorbs blood, closing its pores and forming a seal.

The representative claim of one of the asserted patents recites a device comprising a fluid reservoir “at least partially defined by a seal member and a vent.” The representative claim of the other patent recites a “diverter.”

During claim construction, the district court construed “diverter” as a means‑plus‑function term under § 112(f). Because the Kurin Lock lacked a corresponding diverter structure, the parties stipulated noninfringement of that patent.

The district court did not expressly construe the “seal” and “vent” limitations of the other patent at Markman. At trial, however, the jury found that Kurin infringed that patent.

Kurin moved for judgment as a matter of law (JMOL), arguing that it did not infringe because the Kurin Lock did not include separate seal and vent structures. Instead, a single porous plug performed both functions at separate times. The district court agreed and granted JMOL of no infringement. Magnolia appealed.

The Federal Circuit affirmed, rejecting Magnolia’s argument that the district court had improperly adopted a new claim construction at the JMOL stage. While courts may not introduce a materially different construction after trial, they may elaborate on what is inherent in the plain and ordinary meaning of a claim. The Federal Circuit reiterated its prior holdings that when a claim separately lists structural limitations, the plain and ordinary meaning requires separate corresponding structures. Here, the district court merely clarified that requirement, it did not change the construction.

The Federal Circuit found that the asserted claim required separate structures. The use of “comprising,” the introduction of “a” before both “seal” and “vent,” and the use of “and” between them all pointed to distinct components. The specification further reinforced that the seal and vent were described as separate structures.

The Federal Circuit also affirmed the district court’s construction of “diverter” as a means plus function limitation. Although the claim did not use the word “means,” Kurin successfully showed that the term failed to recite sufficient structure, triggering § 112(f).

Practice note: This case is a reminder that when multiple structural elements are separately recited in a claim, courts are likely to require [...]

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The meaning is plain as day: Just follow the grammar

The US Court of Appeals for the Federal Circuit reversed and vacated a decision by the Patent Trial & Appeal Board, explaining that the Board failed to consider common textual modifier language when applying the plain meaning to a disputed claim term. Netflix, Inc. v. DivX, LLC, Case No. 24-1541 (Fed. Cir. Feb. 13, 2026) (Moore, C.J.; Dyk, Taranto, JJ.)

DivX sued Netflix for infringing its patent directed to systems and methods for streaming partly encrypted media content. The patent uses encryption/decryption, a Digital Rights Management (DRM) technique, to protect streams of media content from unauthorized access or copying. This technique requires that cryptographic information be relayed to the playback device for users to watch streamed media content. The patent explains that encrypting parts of streamed media decreases the resources needed for encryption/decryption and provides the playback device with information on the portions that are encrypted and “common” decryption information.

Netflix petitioned for inter partes review (IPR) of all claims on the basis of obviousness. The Board rejected DivX’s proposed construction of limitation [l] of the representative claim: “locating encryption information that identifies encrypted portions of frames of video within the requested portions of the selected stream of protected video.” DivX’s argued that the “encryption information” must be located “within the requested portions of the selected stream of protected video.” The Board deemed DivX’s proposed claim construction as “too restrictive,” concluding that the claim suggested that the encryption information just needed to identify encrypted portions of frames that themselves were “within the requested portions of the selected stream of protected video.”

In its final written decision, the Board agreed with Netflix that a person of skill in the art would have been motivated to combine the asserted prior art but held that the artisan would not have reasonably expected success in combining the prior art and that therefore Netflix did not establish obviousness of the challenged claims.

The Federal Circuit vacated the Board’s decision on appeal and remanded the matter. On remand, the Board again concluded that Netflix did not demonstrate obviousness but this time accepted DivX’s originally proposed claim construction. Netflix appealed.

The Federal Circuit found the Board’s construction of limitation [l] was erroneous, agreeing with Netflix that limitation [l] was taught by the asserted prior art combination. Using the plain language doctrine, the Court found that limitation [l] was susceptible to two interpretations: “the modifier ‘within the requested portions of the selected stream of protected video’ could modify either ‘encrypted portions of frames of video’ or ‘encryption information.’” Accordingly, the Court relied on the principle that where commas or other textual signals are not used, it is presumed that the modifier is tied to the nearest available semantically plausible modificand. The Court determined that only the “encrypted portions of frames of video” needed to be “within the requested portions of the selected stream of protected video.” The Federal Circuit also determined that the context of the claim itself, the specification, and the prosecution history supported the construction that [...]

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Here’s an abstract idea: Patent eligibility depends on what is claimed, not unclaimed disclosure

The US Court of Appeals for the Federal Circuit reversed a district court’s rejection of Netflix’s 35 U.S.C. § 101 challenge, finding that claims directed to tailoring content specifications for wireless devices were patent ineligible. GoTV Streaming, LLC v. Netflix, Inc., Case Nos. 24-1669; -1744 (Fed. Cir. Feb. 9, 2026) (Prost, Clevenger, Taranto, JJ.)

GoTV sued Netflix for direct and induced infringement of three related patents directed to server-based tailoring of content for wireless devices. The district court dismissed the induced infringement claims and rejected Netflix’s § 101 challenge. A jury found infringement of one of the asserted patents and awarded $2.5 million in damages. Netflix appealed.

The Federal Circuit reversed the district court’s indefiniteness ruling as to a key term of the representative patents and adopted GoTV’s proposed construction of that claim term: “discrete low level rendering command.” Based on its construction, the Court concluded that the asserted claims were directed to an abstract idea and lacked an inventive concept under Alice. The Court concluded that the claims merely recited the abstract idea of using a generic template tailored to a user’s device constraints and relied on conventional computer and network functions without specifying a concrete technological improvement. The Federal Circuit determined that the claims failed both steps of the Alice framework and were invalid under § 101.

Although its § 101 holding resolved the case in Netflix’s favor, the Federal Circuit vacated the district court’s summary judgment of no inducement and its denial of GoTV’s motion for a new trial on damages, explaining that GoTV had presented substantial arguments on those issues, before directing entry of final judgment for Netflix.

Practice note: The Federal Circuit noted that the ineligibility analysis depends on the claim language at issue, not whether there may be a patent eligible invention disclosed in the specification. Although the prosecution history may be intrinsic evidence for claim construction, recitation of the problems faced by the inventor and the inventive solution cannot be relied on to argue unclaimed details of the invention to render an abstract idea patent eligible.




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Method steps must be done in order where there is logical dependency

In a second appeal, the US Court of Appeals for the Federal Circuit affirmed a district court’s summary judgment of noninfringement based on an implicit ordering of steps in a method claim after disagreeing with the lower court on another basis for noninfringement. Sound View Innovations, LLC v. Hulu, LLC, Case No. 24-1092 (Fed. Cir. Jan. 29, 2026) (Chen, Prost, Wallach, JJ.)

At the district court, Sound View asserted an expired patent against Hulu’s use of a central content server connected to end users through intermediate edge servers. The asserted claim recites downloading streaming content from a buffer in a helper server to an end user while concurrently retrieving more streaming content from a content server.

The district court issued a decision in favor of Hulu, which Sound View appealed. In that first appeal, the Federal Circuit vacated and remanded the district court’s ruling, based on the district court’s negative claim construction.

On remand, the district court determined Hulu did not infringe, finding that the claimed method requires the steps of “receiving a request” and “allocating a buffer” to be performed in sequence. Since Hulu did not perform these claimed steps in order, the district court found there was no infringement. Sound View appealed.

The claim-at-issue recites:

Source: Sound View Innovations, LLC v. Hulu, LLC, Case No. 24-1092 (Fed. Cir. Jan. 29, 2026), Slip Op. at 4.

The Federal Circuit reasoned that the phrase “requested SM object” in the buffer-allocation step grammatically and logically depended on the prior step of “receiving a request,” because an object cannot be “requested” until a request has occurred. The Court explained that “‘requested’ is not only a grammatical descriptor, but also is a status indicator reflecting a completed action – the receiving of a request.”

The Federal Circuit applied precedent on implicit ordering of method steps and noted that “[o]ur caselaw on implicit ordering does not help Sound View, as it does not require a finding that the performance of the claimed steps would be inoperable if the steps are not followed in the order they appear in the claim” (emphasis added). The Court explained that the “logical” dependency between the method steps mandates that the request-receiving step precede buffer allocation. Because there was no dispute that the accused systems performed these steps in a different order, the Court affirmed summary judgment of noninfringement.




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Equivalents still requires all elements be met, injunctive relief still governed by eBay factors

The US Court of Appeals for the Federal Circuit issued a mixed ruling in a dispute over patents covering child car seat technology, explaining that infringement under the doctrine of equivalents requires an equivalent for each and every claim element, and that a grant of injunctive relief requires proof of all eBay factors. On the issue of willfulness, the panel majority held that the exclusion of exculpatory evidence was a reversable error. Wonderland Switzerland AG v. Evenflo Co., Inc., Case Nos. 23-2043; -2233; -2326 (Fed. Cir. Dec. 17, 2025) (Moore, Prost, JJ.) (Reyna, J., concurring in part and dissenting in part).

Wonderland owns two patents directed to convertible child car seats. Wonderland alleged that Evenflo’s four-in-one convertible seat models infringed its patents. A jury found infringement of one patent under the doctrine of equivalents and infringement of the other patent both literally and under the doctrine of equivalents. The district court entered judgment and permanently enjoined Evenflo from activities related to both patents. Evenflo appealed.

Evenflo challenged the finding of infringement under the doctrine of equivalents for the first patent, arguing that its accused seats lacked the claimed “locking mechanism for selectively detachably connecting” the seat back to the seat assembly. The Federal Circuit agreed, finding that no reasonable jury could find equivalence because the claim “plainly requires the seat back to include the components for selective detachability,” whereas Evenflo’s seats “simply include a stationary metal bar” and all locking components reside on the seat assembly. As a result, the Court concluded “there c[ould] be no equivalence as a matter of law.”

Evenflo also argued that the district court abused its discretion in permanently enjoining activities relating to both patents. Regarding the first patent, the Federal Circuit found that the district court abused its discretion in granting a permanent injunction because Wonderland expressly declined to request such relief. Wonderland argued the grant of a permanent injunction as to the first patent was harmless error because it had the same “practical effects” as the injunction for the second patent. The Court disagreed, explaining that the injunction could affect Evenflo’s release of other products, which may not necessarily infringe the second patent.

Regarding the second patent, the Federal Circuit concluded that the district court abused its discretion in granting a permanent injunction because it relied solely on speculative and conclusory evidence that Wonderland suffered, and would continue to suffer, irreparable harm or injury that could not be compensated with monetary damages. The Court explained that the district court failed to identify evidence that Wonderland’s partner lost sales or market share to Evenflo rather than other competitors, or that the partner’s reputation or product distinctiveness was harmed. The Court also noted that testimony that a lost car seat sale “naturally leads” to loss of other product sales was based on conjecture without supporting data. Finally, the Court found that statements that consumers “might think” technology problems existed if Evenflo’s product failed were deemed speculative and insufficient to establish irreparable harm.

Wonderland cross-appealed, asserting [...]

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From ‘best’ to bust: Multiple methods to determine “optimal/best” render claims indefinite

The US Court of Appeals for the Federal Circuit affirmed a district court’s judgment of invalidity and grant of summary judgment of noninfringement, concluding that even if excluded portions of expert testimony were considered, the judgments would remain proper. Akamai Technologies, Inc. v. MediaPointe, Inc., AMHC, Inc., Case No. 24-1571 (Fed. Cir. Nov. 25, 2025) (Taranto, Stoll, Cunningham, JJ.)

AMHC owns two patents that address systems and methods for efficiently routing streamed media content over the internet using an “intelligent distribution network” that centrally manages requests for streamed media from geographically dispersed users to mitigate bandwidth problems inherent in transmitting large volumes of data. Akamai sued AMHC and its subsidiary MediaPointe (collectively, MediaPointe) seeking a declaratory judgment of noninfringement for both patents. MediaPointe counterclaimed for infringement of both patents, after which Akamai counterclaimed for declaratory judgment of invalidity of all claims of both patents.

At the claim construction stage, the district court determined that claim limitations using “optimal/best” language were invalid for indefiniteness because the specification failed to provide a procedure or boundaries to determine what is “optimal/best.” For the remaining asserted claims, the district court granted summary judgment of noninfringement. In doing so, the district court:

  • Excluded as untimely presented key portions of MediaPointe’s technical expert’s testimony, without which MediaPointe could not reasonably establish infringement
  • Ruled that even if the testimony was considered, the record entitled Akamai to summary judgment of noninfringement.

MediaPointe appealed.

MediaPointe contended that the claims using “optimal/best” language were not indefinite, arguing that the requirement to use measurable performance data (specifically “trace-route results”) provided an objective standard. The Federal Circuit disagreed, finding that this requirement did not supply a reasonably clear and exclusive definition of “optimal/best.” The Court explained that the “trace-route results” requirement was not sufficiently clear because multiple methods could be used to determine compliance, and the patent offered no guidance on which measures to apply.

MediaPointe also challenged the summary judgment of noninfringement for the remaining claims, arguing that the district court applied an improperly narrow construction instead of the ordinary meaning of the disputed limitation. The Federal Circuit rejected this argument, finding that a skilled artisan would not have reasonably understood the claim language more broadly and that the district court’s construction was correct in light of the patent’s context. The Court concluded that because there was no evidence that Akamai’s system met this narrower limitation, even considering the excluded expert testimony, there was no triable issue of fact and no reasonable jury could find infringement.

The Federal Circuit therefore affirmed the district court’s judgment.




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Well, well, well: Indefinite claims turn out to be a typo

The US Court of Appeals for the Federal Circuit reversed a district court ruling that invalidated patent claims for indefiniteness, finding that the disputed language was a minor clerical error. Canatex Completion Solutions, Inc. v. Wellmatics, LLC, et al., Case No. 24-1466 (Fed. Cir. Nov. 12, 2025) (Moore, Prost, Taranto, JJ.)

Canatex sued Wellmatics and several GR Energy entities for infringing its patent directed to a releasable connection for a downhole tool string. The patent covers a two-part device used in oil and gas wells that allows operators to disconnect and retrieve the upper part of the tool string while leaving the lower part in the well if it becomes stuck.

The patent’s claims, abstract, and specification include the phrase “the connection profile of the second part.” During claim construction, the defendants argued that the phrase lacked an antecedent basis, rendering the claims indefinite. Canatex responded that the phrase should have read “the connection profile of the first part” and that a skilled artisan would immediately recognize the error. Canatex asked the district court to construe the phrase accordingly.

The district court disagreed, finding that the “pervasiveness of the error” in both the claims and the specification suggested that the error “was an intentional drafting choice and not an error at all.” The district court added that Canatex’s failure to seek correction from the United States Patent and Trademark Office suggested that the error was neither minor nor evident on the face of the patent. The district court found all asserted claims invalid for indefiniteness. Canatex appealed.

The Federal Circuit reversed. The Court found the error obvious and determined that a skilled artisan would recognize only one reasonable correction, which was changing “second” to “first.” The Court characterized the mistake as a minor clerical or typographical error and rejected arguments that alternative interpretations were plausible. The Court emphasized that its conclusion was consistent with the intrinsic evidence.




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