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

by Lauren Hong | Dec 4, 2025 | Patents

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.

Reframing the claim: Plain and ordinary meaning falls to lexicography

by Lauren Hong | Nov 6, 2025 | Patents

The US Court of Appeals for the Federal Circuit affirmed a district court’s construction of a claim, finding that the plain and ordinary meaning of a disputed term was redefined by the patentee under principles of lexicography and use of intrinsic claim construction evidence. Aortic Innovations LLC v. Edwards Lifesciences Corp., et al., Case No. 24-1145 (Fed. Cir. Oct. 27, 2025) (Prost, Reyna, Chen, JJ.)

Aortic sued Edwards Lifesciences for infringing its patents directed toward a transcatheter valve with a frame component. During claim construction, the district court determined that Aortic had acted as its own lexicographer and redefined the term “outer frame” to be “a self-expanding frame,” based on the interchangeable use of the terms “outer frame,” “self-expanding frame,” and “self-expanding outer frame” when referring to the same structure in two embodiments. Based on this construction, the parties stipulated to noninfringement of the asserted patents since Edwards’ accused valve did not have a self-expanding frame. Aortic appealed the judgment of noninfringement, challenging the district court’s construction of the claim term “outer frame.” Aortic appealed.

Aortic contended that “outer frame” should be given its plain and ordinary meaning of “positioned outside” and argued that the specification did not support limiting “outer” to require “self-expanding.” The Federal Circuit disagreed, relying on both lexicographical and specification-based grounds for its construction.

In applying principles of lexicography, the Federal Circuit reasoned that if a person of ordinary skill in the art (POSITA) would understand that two claim terms were used consistently and interchangeably throughout a patent specification, those terms may be considered definitionally equivalent. Referring to several examples, the Court observed that Aortic used “outer frame,” “self-expanding frame,” and “self-expanding outer frame” interchangeably throughout the specification when describing the frame, and concluded that “outer frame” was properly construed to require “self-expanding.”

With regard to using the specification as intrinsic claim construction evidence, the Federal Circuit reasoned that the specification consistently described the “outer frame” as a “self-expanding frame” and did not restrict that feature to a particular embodiment. From this, the Court concluded that the absence of any express exception or explanation would lead a POSITA to understand that the valve’s construction required a self-expanding outer frame in all embodiments.

Aortic alternatively argued that Edwards should be judicially estopped from arguing for a construction of “outer frame” that departed from its plain and ordinary meaning. Aortic asserted that Edwards had previously argued before the Patent Trial & Appeal Board that “outer frame” should be defined using its plain and ordinary meaning, but later adopted a contrary position in front of the district court, contending that the term referred only to a “self-expanding frame.” The Federal Circuit disagreed and explained that Aortic failed to sufficiently develop its judicial estoppel argument before the district court. Absent any exceptional circumstances, the Court concluded that Aortic had forfeited the argument.

Finding Aortic’s arguments unpersuasive, the Federal Circuit affirmed the district court’s judgment of noninfringement as to the asserted patents, upholding the district court’s construction of the disputed claim [...]

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Boss move: Disclaimer that doesn’t work can still work as a disclaimer

by Joshua Revilla | Oct 30, 2025 | Patents

The US Court of Appeals for the Federal Circuit affirmed a district court’s judgment of noninfringement and no invalidity for indefiniteness, concluding that the court correctly construed the claims and properly determined that the patents’ specifications and prosecution histories would enable a person of ordinary skill in the art (POSA) to ascertain the scope of the claims with reasonable certainty. Barrette Outdoor Living, Inc. v. Fortress Iron, LP, Fortress Fence Products LLC, Case Nos. 24-1231; -1359 (Fed. Cir. Oct. 17, 2025) (Moore, Linn, Cunningham, JJ.)

Barrette sued Fortress for infringing its patents directed to a fencing assembly featuring pivoting, sliding connectors that connect pickets to rails. During claim construction, the district court determined that the terms “boss,” “projection,” and “nub” should be given the same meaning and that these “boss” terms described fastener-less and integral structures, distinguishing them from prior art. The district court also held that the terms “sliding” and “causes” were not indefinite because a POSA would understand their scope.

Following the Markman hearing, Barrette stipulated that it could not prove infringement under the court’s construction of the “boss” terms because the accused products used non-integral fasteners. Fortress stipulated, under the same construction, that it could not establish invalidity for indefiniteness. Barrette appealed, and Fortress cross-appealed.

Barrette first argued that the district court erred in finding that the specification disclaimed bosses with fasteners by disparaging prior art assemblies that used them. According to Barrette, the specification did not criticize the use of fasteners but merely distinguished the prior art designs. Fortress, however, argued that the specification repeatedly criticized assemblies employing fasteners, describing prior art systems that used fasteners to join the rails as time consuming to install. In contrast, the patented invention attributes its quick installation advantage to the use of fastener-less, integral bosses.

The Federal Circuit agreed with Barrette that the specification did not clearly and unmistakably disclaim bosses that use fasteners. The Court explained that while a patent may describe multiple advantages over the prior art, not every embodiment must incorporate each of those advantages. Accordingly, claims should not be construed to require every advancement disclosed in the specification. The Court further rejected Fortress’ argument that the claimed “boss” must always achieve the benefit of quick installation. Although the asserted patents describe ease of installation as an advantage of using bosses, that benefit does not limit the term’s structural scope. A “boss,” the Court held, is not restricted to fastener-less configurations. Accordingly, the Federal Circuit determined that the district court erred in limiting the claims to fastener-less bosses.

Barrette next argued that the district court erred by concluding that the prosecution history disclaimed non-integral bosses. The Federal Circuit rejected this argument and agreed with the district court that Barrette had clearly disclaimed non-integral boss structures during prosecution. The Federal Circuit stated that Barrette clearly distinguished prior art from the “claimed integral boss” in prosecution and expressly clarified the scope of its claims.

Barrette argued that its subsequent communications with the patent office rendered any purported disclaimer [...]

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Failure to reassess subject matter eligibility after similar claims invalidated justifies attorneys’ fees

by Amol Parikh | Oct 30, 2025 | Patents

Following a dismissal on the pleadings, the US District Court for the Southern District of New York granted the defendant’s motion for attorneys’ fees under 35 U.S.C. § 285 after concluding that the asserted patent was objectively invalid under 35 U.S.C § 101. Linfo, LLC v. Aero Global, LLC, Case No. 24-cv-2952 (S.D.N.Y. Oct. 15, 2025).

Linfo sued Aero Global alleging infringement of a patent directed to a system with methods and a user interface for discovering and presenting information in text content with different view formats. The patented system would allow a user to sort through online hotel reviews, for example, by toggling a button to show only positive comments, or only comments related to room service.

One week after filing its complaint, Linfo proposed an early-stage settlement of $49,000, which Aero Global did not accept. Subsequently, in a separate case involving the same patent, another judge in the Southern District of New York found the patent invalid. After Aero notified the court of the decision, Linfo sought to dismiss the case without prejudice, and Aero opposed. Linfo then requested a stay pending appeal of the other’s judge’s decision, which the court denied. Linfo then contacted Aero to propose the parties “walk away to close the matter.” Aero responded that it would agree to dismissal if Linfo reimbursed Aero for its fees incurred. Linfo did not respond, after which the court concluded that Linfo was collaterally estopped from asserting infringement of the patent and granted Aero’s motion for judgment on the pleadings.

Aero thereafter sought attorneys’ fees under § 285, arguing that the asserted patent was objectively invalid under § 101. The district court agreed, finding that the litany of cases published after the Supreme Court’s 2014 Alice v. CLS decision should have made clear to Linfo and its counsel that the asserted patent was directed precisely to the kind of abstract concept that Alice deemed unpatentable. Linfo argued that since the patent was issued after the Alice decision, it was reasonable for Linfo to assume the patent examiner considered Alice as part of the USPTO’s decision-making process. The district court rejected this argument, finding no evidence that the USPTO evaluated whether the patent was directed to patent eligible subject matter and, more importantly, finding that numerous cases post-dating the patent’s issuance invalidated patents similar to Linfo’s patent.

Linfo argued that it was reasonable for it to continue the case because it received favorable claim construction rulings and litigated against other defendants that had not filed § 101 challenges. The court rejected this argument, explaining that judicial construction of a patent claim after a claim construction hearing says little about whether that claim is eligible under § 101, given that claim construction and patent eligibility are distinct inquiries.

The court considered Linfo’s and its attorney’s litigation history and found several indicia suggesting that Linfo and its counsel brought this case to induce settlement rather than to reach the merits. The court noted that Linfo had asserted the challenged patent [...]

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Power outage: Assignment doesn’t include future improvements

by Sydney E. McDermott | Oct 23, 2025 | Patents

In a pair of related rulings, the US Court of Appeals for the Federal Circuit reviewed two decisions from two different agencies involving the same patent. The Court ultimately found that the International Trade Commission (ITC) correctly identified the owner of the asserted patent, and that the Patent Trial & Appeal Board correctly determined that the asserted patent was unpatentable. Causam Enterprises, Inc. v. Int’l Trade Comm’n, Case No. 23-1769 (Fed. Cir. Oct. 15, 2025) (Taranto, Chen, Stoll, JJ.); Causam Enterprises, Inc. v. ecobee Techs. ULC, Case No. 24-1958 (Fed. Cir. Oct. 15, 2025) (Taranto, Chen, Stoll, JJ.)

Causam initiated a complaint before the ITC, alleging that certain importers infringed its patent directed to technology for reducing electrical utilities power demands. The asserted patent claims priority as a continuation-in-part of a parent patent application. Although the face of the asserted patent lists Causam as the assignee, the parent application was assigned to another entity a decade earlier, along with “all patents which may be granted therefor” and “all divisions, reissues, continuations, and extensions thereof.” The assignment did not expressly include continuations-in-part.

The chief administrative law judge (ALJ) issued an initial determination that Causam was not the owner of the asserted patent and that no infringement had occurred. Causam subsequently requested a review of the initial determination by the full Commission. The Commission adopted the ALJ’s findings of noninfringement but declined to adopt the findings regarding ownership. Causam appealed.

Ownership of a patent is a threshold requirement for asserting Article III standing, and the complainant bears the burden of establishing standing in the pleadings. On appeal, the Commission and the ITC respondents argued that ownership of the asserted patent did not need to be decided for standing purposes as Causam had pleaded ownership in its complaint. The Federal Circuit disagreed, emphasizing that, as an Article III court, it is required to consider Article III’s standing requirements, even if the ITC is not. Because the issue turned on contract interpretation and did not require underlying factual findings, the Federal Circuit reviewed the standing issue de novo.

The Federal Circuit ultimately determined that the omission of the term “continuation-in-part” from the assignment agreement meant that the asserted patent was not included in the assignment and thus Causam had ownership of the asserted patent. The ITC respondents argued that the inclusion of “continuation” language was sufficient to encompass both continuations and continuations-in-part. The Court rejected this argument, noting that adopting such a position would effectively “insert words into the contract that the parties never agreed to,” particularly because continuations and continuations-in-part (which by definition include new matter not found in the priority application) are widely understood to be distinct concepts within patent law.

The Federal Circuit noted that such a distinction is especially significant in the context of patent assignments. In the case of continuations, recordation of the assignment of the parent patent or application is effective as to a child patent. In contrast, the same is not true for a continuation-in-part, meaning that [...]

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Surprise? Last-minute new theory leads to new trial

by Dexter Hamilton | Sep 18, 2025 | Patents

The US Court of Appeals for the Federal Circuit reversed a district court’s denial of a new trial after the defendant introduced a new noninfringement theory on the eve of trial based on test results it previously refused to produce, saying they were not necessary. Magēmā Technology LLC v. Phillips 66, Phillips 66 Co., and WRB Refining LP, Case No. 2024-1342 (Fed. Cir. Sept. 8, 2025) (Moore, Stoll, Bumb, JJ.)

Magēmā owns a patent directed to a solution to desulfurize fuel used to power cargo ships. Magēmā entered into licensing discussions with Phillips, but after the parties failed to reach an agreement, Phillips modified its hydrotreater reactors to implement what Magēmā believed was an infringing desulfurization process. Magēmā sued.

The governing fuel standard required a flashpoint of at least 140 degrees, meaning fuel with a pre-hydroprocessing flashpoint below that threshold would not infringe. The parties disagreed on where at the refinery the flashpoint should be tested. Phillips provided data from one sampling point while Magēmā requested data from a location closer to the hydrotreater reactor. Phillips refused, citing safety concerns, and argued that Magēmā could estimate the flashpoint using an accepted formula. The district court denied Magēmā’s motion to compel, agreeing that the formula sufficed. However, after discovery closed, Phillips moved to supplement the summary judgment record with new flashpoint test results from a different sampling station. The district court denied the motion, finding Phillips had no reasonable explanation for failing to sample earlier, and that introducing the evidence late would be unduly prejudicial, especially since Phillips had previously said Magēmā could rely on the formula. Yet shortly before jury selection, Magēmā learned that Phillips intended to argue that the formula was inadequate and that only actual testing could prove infringement (evidence Magēmā lacked), effectively shifting the burden. Magēmā objected, but the district court overruled the objection.

At trial, Philips told the jury that the standard required actual flashpoint testing and that Magēmā could not prove infringement without test samples. Magēmā requested a curative instruction, which the district court denied. The district court also barred Magēmā from explaining why it had relied on a formula rather than actual testing data. The jury returned a general verdict of noninfringement. Although the district court acknowledged that Phillips’ arguments were “improper and prejudicial,” it denied Magēmā’s motion for a new trial, finding that the misconduct did not affect the outcome. Magēmā appealed.

Phillips argued that Magēmā had failed to timely object, but the Federal Circuit disagreed, citing to Magēmā’s pre-jury selection objection, request for a curative instruction, and motion for a new trial. Finding that the district court abused its discretion in denying a new trial, the Federal Circuit agreed that Phillips’ argument was “improper and prejudicial,” characterizing it as a “bait-and-switch.”

Because the jury returned a general verdict form, the Federal Circuit could not determine the basis for the noninfringement finding and, given the repeated emphasis Phillips placed on its improper argument, the Court concluded it would be unjust to let the [...]

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Claims barred by laches: Prosecution delay doesn’t pay, nor does skipping evidence of concrete injury

by Courtney Seams | Sep 11, 2025 | Patents

The US Court of Appeals for the Federal Circuit affirmed a district court’s judgment for the US Patent & Trademark Office (PTO) on application of prosecution laches in an action under 35 USC § 145. The Federal Circuit also agreed that the district court lacked Article III jurisdiction over certain claims because the plaintiff failed to provide evidence of concrete injury when challenged after initial pleadings. Hyatt v. Stewart, Case Nos. 2018-2390; -2391; -2392; 2019-1049; -1038; -1039; -1070; 2024-1992; -1993; -1994; -1995 (Fed. Cir. Aug. 29, 2025) (Reyna, Wallach, Hughes, JJ.) (precedential).

Gilbert Hyatt filed four GATT bubble patent applications, all of which had claims rejected by the examiner. Hyatt appealed those rejections to the Patent Trial & Appeal Board, which affirmed various rejections of others. Following the Board decisions, Hyatt filed four separate actions in district court under 35 U.S.C. § 145, challenging the PTO rejections. In response, the PTO asserted prosecution laches as an affirmative defense and, in the alternative, invalidity, based on anticipation and lack of written description.

The district court initially ruled in Hyatt’s favor, finding that the PTO’s affirmative defenses failed with respect to the claims for which the Board affirmed the examiner’s rejection. The district court concluded that it lacked Article III jurisdiction over the remaining claims (those for which the Board reversed the examiner) because there was no final agency action as to those claims.

The PTO appealed, arguing that prosecution laches barred all of the claims or, in the alternative, that the claims were invalid. Hyatt cross-appealed, contending that prosecution laches did not apply in § 145 actions or that the district court abused its discretion in applying laches in these specific § 145 actions.

In an earlier appeal, Hyatt I, the Federal Circuit vacated the district court’s rulings on prosecution laches, holding that the district court applied the wrong standard for prosecution laches and had the burden of proving that Hyatt engaged in unreasonable and unexplained delay in prosecuting his applications and that the delay was prejudicial. The panel remanded the case held the issue of Article III jurisdiction in abeyance. On remand, the district court reversed course and found in favor of the PTO on prosecution laches, concluding that Hyatt had unreasonably delayed prosecution in a manner that prejudiced the agency.

Hyatt appealed. The Federal Circuit consolidated the appeals with the earlier stayed jurisdictional issues. The Federal Circuit affirmed the district court’s application of prosecution laches, finding no clear error in its determination that Hyatt’s conduct met the standard for delay and prejudice. The Federal Circuit also agreed that the district court lacked Article III jurisdiction over claims that had not been finally rejected by the PTO, reinforcing that § 145 actions may only proceed where there is a final agency determination resulting in a justiciable controversy.

On the issue of prosecution laches, the Federal Circuit explained that it had already considered and rejected Hyatt’s argument that prosecution laches is unavailable in a § 145 action in Hyatt I, and [...]

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Standing: Don’t get owned by incorrect trademark ownership

by Jolie B. Schenerman | Sep 4, 2025 | Trademarks

The US Court of Appeals for the Second Circuit affirmed a district court’s dismissal of a trademark and unfair competition suit, ruling that the plaintiff did not own the asserted trademark. The Court also held that the owner of the trademark failed to ratify the action and therefore the plaintiff did not have standing to assert unfair competition claims. Ripple Analytics Inc. v. People Ctr., Inc., Case No. 24-490 (2d Cir. Aug. 26, 2025) (Park, Nathan, Perez, JJ.)

In March 2018, the US Patent & Trademark Office granted Ripple Analytics a federal trademark for RIPPLE in connection with human resources software. The following month, Ripple assigned all rights to its intellectual property to co-founder Noah Pusey via an assignment agreement. Around the same time, People Center applied to register RIPPLING for similar software. It later abandoned the application but continued to operate under the Rippling name.

Ripple sued People Center in 2020 for trademark infringement and unfair competition. During discovery, Ripple produced the assignment agreement. People Center responded by moving to amend its answer, seeking dismissal for failure to prosecute in the name of the real party in interest and requesting summary judgment.

The district court found that Pusey, not Ripple, was the real party in interest and dismissed the case because Pusey had not ratified the action under Federal Rule of Civil Procedure 17. It also dismissed the unfair competition claims for lack of standing and denied Ripple’s motion to amend the complaint as futile. Ripple appealed.

The Second Circuit affirmed the dismissal, finding that Ripple had “unambiguously” assigned all intellectual property rights, including the trademark at issue, to Pusey, making him the real party in interest. The Court emphasized that the assignment agreement transferred all of Ripple’s “claims, causes of action, and rights to sue,” regardless of when those claims arose. Ripple argued that Pusey satisfied Rule 17 by ratifying the pleadings and agreeing to be a plaintiff. The Court rejected this argument, noting that Pusey’s declaration stating his involvement in the case and strong interest in its outcome did not amount to an agreement to be bound by the suit, a requirement for ratification.

The Second Circuit determined that Ripple’s Lanham Act unfair competition claims failed because they were based on the inaccurate assertion that Ripple owned the RIPPLE mark. The Second Circuit also upheld the district court’s denial of Ripple’s motion to amend its complaint, explaining that the assignment agreement expressly barred Ripple from bringing suit.

Practice note: Before initiating trademark litigation, practitioners should conduct thorough due diligence on ownership to avoid standing issues. Defendants should consider initiating early discovery on ownership of the rights being asserted.

Identical or not? Jury can’t decide issues of claim construction

by Cecilia Choy, PhD | Aug 21, 2025 | Patents

The US Court of Appeals for the Federal Circuit reversed a district court’s denial of a motion for judgment as a matter of law (JMOL) of noninfringement, finding that the jury’s infringement findings were unsupported by sufficient evidence and that the district court had improperly delegated claim construction to the jury. Laboratory Corp. of America Holdings v. Qiagen Sciences, LLC, Case No. 23-2350 (Fed. Cir. Aug. 13, 2025) (Lourie, Dyk, Cunningham, JJ.)

Laboratory Corp. of America Holdings (LabCorp) holds two patents with substantially overlapping specifications, both generally directed to methods for preparing DNA samples for sequencing and enrichment techniques aimed at enabling whole-genome sequencing. LabCorp initiated litigation alleging that various Qiagen Sciences kits containing materials used in DNA sample preparation for sequencing infringed its patents. During claim construction, the district court construed several patent terms as follows:

In the first patent, “second target-specific primer” means a single-stranded oligonucleotide with a 3’ portion that specifically anneals to a portion of the known target nucleotide sequence in the amplicon from step (b), and a 5’ portion identical to a second sequencing primer.
Also in the first patent, “second adaptor primer” refers to a nucleic acid molecule containing a sequence identical to part of the first sequencing primer and nested relative to the first adaptor primer.
In the second patent, “target-specific primer” is defined as a primer sufficiently complementary to the target to enable selective annealing and amplification, without amplifying non-target sequences in the sample.

The jury found that Qiagen infringed the first patent under the doctrine of equivalents and willfully and literally infringed the second patent. The jury awarded damages accordingly. The district court denied Qiagen’s renewed motion for JMOL to reverse the damages and the jury’s findings of infringement and validity, and its alternative request for a new trial. Qiagen appealed.

Qiagen raised two noninfringement arguments regarding the first patent, and the Federal Circuit agreed with both. First, the Court held that it was error to allow the jury to apply “plain meaning” and equate a sequence being “identical to another” with being “identical to a portion” of another. Specifically, Qiagen’s accused second target-specific primer (Sample Index Primer, or SIP) was 19 nucleotides long while the second sequencing primer (Read2 primer) was 34 nucleotides. The fact that they shared an overlapping sequence did not make them identical.

Although the district court had treated “identical” as a factual issue for the jury, the Federal Circuit, citing its 2008 decision in O2 Micro Int’l Ltd. v. Beyond Innovation Tech., found that this was a claim construction matter that should not have been left to the jury. The term “identical” must be given its full meaning under claim construction and cannot be interpreted as “identical to a portion.” The Court emphasized that the specification and claims distinguished between full and partial identity: The second target-specific primer must be “identical to” the second sequencing primer while the adaptor primer need only be “identical to a portion” of the first sequencing primer. This difference [...]

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Specification controls: Written description must be clear

by Taylor MacDonald | Aug 21, 2025 | Patents

The US Court of Appeals for the Federal Circuit reversed a district court’s decision upholding patent validity, finding that the subject patent’s specification clearly established that the written description failed to adequately support the full scope of the asserted claims (35 U.S.C. § 112). Mondis Technology Ltd. v. LG Electronics Inc., Case Nos. 23-2117; -2116 (Fed. Cir. Aug. 8, 2025) (Taranto, Clevenger, Hughes, JJ.)

Mondis sued LG for alleged infringement of a patent related to computer display technology. During prosecution, Mondis amended the claims to overcome prior art, changing a limitation from identifying a particular display unit to identifying a type of display unit (the type limitation). A jury found in favor of Mondis and awarded $45 million in damages. LG moved for judgment as a matter of law (JMOL), arguing that the patent was invalid due to a lack of written description supporting the type limitation. The district court denied the motion but granted a retrial on damages. The second jury awarded more than $14 million. LG appealed.

The Federal Circuit applied regional law standard (here, Third Circuit law) to review the district court’s denial of JMOL (i.e., assessing whether a reasonable jury could have reached the verdict). In evaluating patent validity under the written description requirement of § 112, the Court focused on whether the specification sufficiently demonstrated that the inventor possessed the claimed invention, including any amendments made during prosecution.

The Federal Circuit examined whether substantial evidence supported the jury’s finding of validity and concluded that LG did not need extrinsic evidence to challenge the patent’s validity but properly relied on the specification. The Court found that Mondis’ attempt to piece together fragments of testimony (primarily related to infringement) to argue for implicit support in the specification was insufficient because the specification’s plain language supported only the original unamended claim limitation, not the amended type limitation.

The Federal Circuit acknowledged that both parties presented expert testimony at trial. However, the Court found that even Mondis’ expert testimony, when considered alongside the specification’s plain meaning, failed to provide adequate support for the jury’s finding. While a jury may infer implicit support, Mondis did not present enough particularized testimony to justify such an inference.

Mondis also argued that the examiner’s allowance of the amended claim indicated sufficient support in the specification, and that the presumption of validity of an issued patent supported its position. The Federal Circuit rejected this argument, noting that the examiner’s focus was on overcoming prior art, not on evaluating written descriptions. Accepting Mondis’ position would effectively shield most patents from later invalidation, a result the Court deemed impractical.

Accordingly, the Federal Circuit reversed the district court’s ruling and found the asserted claims invalid for lack of written description.