Technology Information Law Blog by Charles Gideon Korrell

Tag: JMOL

  • Barry v. DePuy Synthes: The Federal Circuit Draws a Line Between Daubert Gatekeeping and Jury Factfinding

    Barry v. DePuy Synthes: The Federal Circuit Draws a Line Between Daubert Gatekeeping and Jury Factfinding

    On January 20, 2026, the Federal Circuit issued a significant decision clarifying the boundary between judicial gatekeeping under Daubert and the jury’s role as factfinder in patent infringement trials. In Barry v. DePuy Synthes Companies, the court reversed the exclusion of two key experts and vacated a judgment as a matter of law entered after the district court struck that testimony mid-trial. The opinion offers an important reminder that not every tension or inconsistency exposed on cross-examination rises to the level of an admissibility defect—and that Rule 702’s reliability inquiry must not be conflated with the merits of an expert’s conclusions.

    Background and Procedural Posture

    Dr. Mark Barry sued DePuy Synthes entities in the Eastern District of Pennsylvania, alleging that DePuy induced surgeons to infringe claims of three patents covering spinal derotation techniques used to treat deformities such as scoliosis. The asserted patents describe tools and methods for “en bloc derotation,” allowing surgeons to manipulate multiple vertebrae simultaneously using linked derotation tools.

    Two categories of claims were at issue. The first required tools with a “handle means,” construed by the district court as “a part that is designed especially to be grasped by the hand.” The second, from a later patent, did not require a handle means but instead required cross-linking elements that caused tools to move in unison.

    Barry relied on two experts. His technical expert, Dr. Walid Yassir, opined that DePuy’s accused tools could be assembled and used in infringing configurations that met every claim limitation. His survey expert, Dr. David Neal, designed and administered a surgeon survey to estimate how often the accused tools were used in those infringing configurations, evidence that fed directly into Barry’s damages theory.

    Before trial, the district court denied DePuy’s Daubert motions directed at both experts, concluding that DePuy’s criticisms went to weight rather than admissibility. During trial, however—after both experts testified—the court reversed course. It excluded Dr. Yassir’s testimony on the ground that he contradicted the court’s claim construction of “handle means,” excluded Dr. Neal’s survey as methodologically unreliable, and then granted judgment as a matter of law for DePuy based on the absence of remaining expert evidence.

    Barry appealed.

    The Federal Circuit’s Majority Opinion

    Writing for the majority, Judge Stark reversed across the board. Applying Third Circuit law to the evidentiary rulings, the court held that the district court abused its discretion in excluding both experts and erred in granting JMOL.

    1. Expert Testimony and Claim Construction

    The majority began from a well-established premise: expert testimony that contradicts a court’s claim construction is not helpful to the jury and must be excluded under Rule 702. The court cited Exergen, Liquid Dynamics, and more recent Federal Circuit precedent reiterating that experts may not present infringement opinions “untethered” from the court’s constructions.

    But the key question, according to the majority, was whether Dr. Yassir actually contradicted the construction—or instead merely applied it in a way DePuy disputed.

    The court emphasized that on direct examination, Dr. Yassir repeatedly recited the court’s construction verbatim and testified that he applied it in his analysis. His opinion was that various parts of the accused tools—including when linked together—were “designed especially to be grasped by the hand.”

    On cross-examination, DePuy elicited testimony that it later characterized as contradictory: statements suggesting that “everything” in a linked system could be a handle means, or that parts grasped during assembly could qualify. The district court viewed these statements as redefining “handle means” to include anything that must be grasped, rather than something designed especially to be grasped.

    The Federal Circuit disagreed. In the majority’s view, these exchanges revealed at most a dispute over how broadly the construction should be applied, not a rejection of the construction itself. The majority stressed that the district court’s own Markman order acknowledged that “handle means” could encompass a linked handle array, and that nothing in the construction precluded multiple components from qualifying when linked together.

    Crucially, the court distinguished between contradiction and lack of persuasiveness. An expert who applies the court’s construction in an expansive or aggressive way may be wrong, but that does not render the testimony inadmissible. As the majority put it, disputes over application, credibility, and probative weight are for the jury—not grounds for exclusion.

    Charles Gideon Korrell notes that this portion of the opinion is best read as a warning against converting Daubert into a vehicle for resolving close infringement questions under the guise of reliability.

    2. Survey Evidence and Rule 702

    The court reached a similar conclusion regarding Dr. Neal’s survey. The district court excluded the survey based on concerns about representativeness, non-probability sampling, nonresponse bias, and alleged flaws in question design.

    The majority acknowledged that surveys must examine the proper universe and use a representative sample, but emphasized that methodological imperfections ordinarily go to weight, not admissibility. The court faulted the district court for failing to identify record evidence demonstrating that the alleged flaws rendered the survey unreliable under Rule 702, as opposed to merely vulnerable to cross-examination.

    Importantly, the majority observed that the district court relied largely on its own assessment of general survey principles rather than testimony from DePuy’s own survey expert tying those principles to fatal defects in Neal’s work. The court cited Third Circuit authority cautioning against excluding expert evidence simply because the judge believes the expert’s conclusions are incorrect.

    Here again, Charles Gideon Korrell believes the decision reflects a broader trend at the Federal Circuit: reaffirming that Daubert is a threshold inquiry into reliability, not a substitute for the adversarial process.

    3. Judgment as a Matter of Law

    Because the district court’s JMOL rested entirely on the absence of expert testimony after the exclusions, the Federal Circuit reversed that ruling as well. With both experts reinstated, the case was remanded for a new trial.

    The Dissent and the Rule 702 Amendments

    Judge Prost dissented, grounding her analysis firmly in the 2023 amendments to Rule 702 and the Federal Circuit’s recent en banc decision in EcoFactor v. Google. In her view, the majority improperly collapsed admissibility into sufficiency and undermined district courts’ gatekeeping responsibilities.

    The dissent characterized Dr. Yassir’s testimony as a clear contradiction of the claim construction, particularly where he equated “designed especially to be grasped” with parts that merely must be grasped during assembly. Similarly, Judge Prost viewed Dr. Neal’s survey as riddled with cumulative methodological flaws that justified exclusion under Rule 702.

    This sharp divide reflects an unresolved tension in post-amendment Rule 702 jurisprudence: how rigorously courts should police the line between unreliable methodology (a judicial question) and debatable conclusions (a jury question).

    Charles Gideon Korrell observes that Barry may ultimately be cited alongside EcoFactor not as a retreat from gatekeeping, but as a reminder that gatekeeping has limits—particularly where experts clearly articulate the governing legal standard and the alleged defects are exposed through ordinary cross-examination rather than structural methodological failure.

    Practical Takeaways

    Several lessons emerge from Barry v. DePuy Synthes:

    1. Contradiction requires more than tension. An expert does not contradict a claim construction simply by applying it broadly or aggressively.
    2. Cross-examination matters. Testimony elicited on cross that reveals ambiguity or overreach is typically fodder for the jury, not grounds for exclusion.
    3. Survey flaws must be tied to unreliability. Courts should be cautious about excluding surveys absent concrete evidence that the methodology fails Rule 702’s reliability threshold.
    4. Mid-trial reversals are risky. Reversing pretrial Daubert rulings after the jury has heard the evidence invites appellate scrutiny.

    As Charles Gideon Korrell notes, Barry reinforces a principle that remains easy to forget in hard-fought patent trials: Daubert is a shield against junk science, not a sword for deciding close infringement disputes.

    Conclusion

    Barry v. DePuy Synthes is less about spinal surgery than about trial mechanics. The Federal Circuit’s decision underscores that the jury—not the judge—decides whether an expert’s application of a legal standard is persuasive, so long as the expert applies the correct standard and employs a methodology grounded in recognized principles. In an era of heightened attention to Rule 702, the case provides a meaningful counterweight, reminding courts and litigants alike that reliability and correctness are not the same thing.

    By Charles Gideon Korrell

  • Finesse Wireless LLC v. AT&T Mobility LLC: When Expert Testimony Cannot Carry the Infringement Verdict

    Finesse Wireless LLC v. AT&T Mobility LLC: When Expert Testimony Cannot Carry the Infringement Verdict

    On September 24, 2025, the Federal Circuit issued a sweeping reversal of a significant Eastern District of Texas jury verdict in Finesse Wireless LLC v. AT&T Mobility LLC, vacating a $166 million damages award and reversing the denial of judgment as a matter of law (JMOL) of noninfringement. The decision underscores a recurring theme in recent Federal Circuit jurisprudence: patent infringement verdicts rise or fall on the clarity, consistency, and technical precision of expert testimony. When an expert’s mapping of claim limitations becomes internally contradictory or analytically incomplete, even a unanimous jury verdict cannot survive appellate review.

    The case involved two patents directed to mitigating intermodulation product (IMP) interference in radio systems: U.S. Patent Nos. 7,346,134 and 9,548,775. Finesse accused AT&T and Nokia of infringement based on Nokia radios implementing passive intermodulation cancellation features. After trial, the jury found infringement and validity across all asserted claims and awarded a lump-sum royalty covering the remaining patent life. The district court denied post-trial motions for JMOL and a new trial. On appeal, the Federal Circuit reversed across the board.

    The ’134 Patent: Sampling Signals That Do Not Yet Exist

    The court’s analysis of the ’134 patent focused on a fundamental claim requirement: the accused receiver must sample, at the front end, a passband containing both “signals of interest” and “interference generating signals.” Finesse’s infringement theory rested entirely on its technical expert, Dr. Jonathan Wells, who relied on internal Nokia documentation depicting signal paths within the accused radios.

    At trial, Dr. Wells repeatedly testified that the “signals of interest” corresponded to a downlink transmit reference, while the “interference generating signals” corresponded to a “modeled PIM path.” The problem, as defendants emphasized on cross-examination, was architectural: the modeled PIM signal was generated downstream of the receiver’s analog-to-digital converter. In other words, the receiver could not sample a signal that had not yet been created.

    Confronted with this issue, Dr. Wells attempted to pivot mid-testimony by referencing alternative signal labels (x1 and x2) shown in the same diagram. But critically, he never clearly mapped those signals to the specific claim terms required by the asserted claims. Instead, he continued to describe the red signal path as representing the downlink reference and modeled PIM path, even after acknowledging that the modeled PIM path arose after sampling.

    The Federal Circuit found this testimony fatally inconsistent. Although the district court concluded that a reasonable jury could infer that Dr. Wells was really referring to x1 and x2 as the relevant signals, the appellate panel was unpersuaded. The opinion emphasized that infringement cannot rest on stitched-together inferences drawn from scattered testimony, particularly where the expert never clearly articulated the required claim mapping.

    Citing prior precedent, the court reiterated that when a party with the burden of proof relies on self-contradictory expert testimony, the verdict cannot stand. The court characterized Dr. Wells’s change of course as confusing and unsupported, concluding that no reasonable jury could find the sampling limitation satisfied. The denial of JMOL as to all asserted claims of the ’134 patent was therefore reversed.

    The ’775 Patent: Seven Multiplications Means Seven Multiplications

    The ’775 patent presented a different, but equally unforgiving, problem. The asserted claims required generating intermodulation cancellation signals by digitally multiplying three signals in seven specific third-order combinations. The infringement case again turned on Dr. Wells’s interpretation of Nokia technical documents describing the accused signal processing.

    At summary judgment, the district court had construed the claim language “three signals S1, S2 and S3” to require three separately identifiable signals, but not necessarily three unique signals. On appeal, defendants did not challenge that construction. Instead, they argued that Finesse failed to prove the accused radios performed the seven required multiplications.

    The Federal Circuit agreed. At trial, Dr. Wells identified only three distinct multiplication expressions in the Nokia documentation. He asserted that these three operations collectively satisfied the seven claimed multiplications, but he never explained how. Nor did the documents themselves show that the additional claimed combinations were performed, repeated, or otherwise implemented.

    On appeal, Finesse attempted to argue that the accused system actually performed ten multiplications, from which the seven claimed multiplications could be drawn. But the court rejected this effort outright. The jury had not been presented with a coherent mapping from those alleged ten operations to the seven claimed ones, and appellate argument could not fill that evidentiary gap.

    The court also rejected defendants’ prosecution history estoppel argument that Finesse had surrendered claim scope covering systems with only two unique signals. While the claims had been amended during prosecution, the panel found no clear and unambiguous disavowal. That issue, however, did not save the verdict. Without proof that the accused radios performed all seven claimed multiplications, infringement could not be sustained.

    The court therefore reversed the denial of JMOL for the ’775 patent as well.

    Damages Fall With Liability

    Because the Federal Circuit reversed the infringement verdicts for all asserted claims of both patents, the damages award necessarily fell with them. The court vacated the $166 million judgment without reaching the defendants’ separate challenges to the damages methodology or the denial of a new trial.

    Takeaways

    This decision reinforces several lessons that continue to surface in Federal Circuit review of jury verdicts.

    First, expert testimony must be internally consistent and precise. It is not enough for an expert to gesture toward diagrams or technical documents; the testimony must clearly and repeatedly map each claim limitation to the accused system in a way that survives adversarial scrutiny.

    Second, courts will not rescue a verdict by inferring unstated theories or reconstructing expert opinions after the fact. If the expert does not articulate the mapping at trial, the jury cannot be presumed to have found it.

    Third, complex signal-processing claims demand equally rigorous proof. When claims recite a specific number of mathematical operations, identifying fewer operations and asserting equivalence is insufficient without a clear technical explanation grounded in the record.

    Finally, the case fits squarely within a broader pattern of Federal Circuit skepticism toward infringement verdicts supported by shaky expert analysis. Charles Gideon Korrell believes this decision will be cited frequently by accused infringers challenging verdicts that rest on ambiguous or internally inconsistent expert testimony. Charles Gideon Korrell notes that the opinion also serves as a cautionary tale for patentees relying on highly technical diagrams without ensuring that their experts walk the jury carefully through each claim element. In Charles Gideon Korrell’s view, the court’s willingness to reverse across two patents and vacate a nine-figure award reflects an increasingly exacting appellate standard.

    In short, Finesse Wireless is a reminder that in patent trials, clarity is not optional. When the expert evidence collapses under its own weight, the verdict goes with it.

    By Charles Gideon Korrell

  • Laboratory Corp. of America Holdings v. Qiagen Sciences, LLC: When “Identical” Means Identical—and the Doctrine of Equivalents Is Not a Jury Mulligan

    Laboratory Corp. of America Holdings v. Qiagen Sciences, LLC: When “Identical” Means Identical—and the Doctrine of Equivalents Is Not a Jury Mulligan

    The Federal Circuit’s decision in Laboratory Corp. of America Holdings v. Qiagen Sciences, LLC, No. 23-2350 (Fed. Cir. Aug. 13, 2025), offers a sharp reminder that not every jury verdict survives appellate scrutiny, particularly where infringement theories stretch claim language or rely on generalized expert testimony. In a sweeping reversal, the court vacated a Delaware jury’s willful infringement verdict covering two molecular diagnostics patents and directed entry of judgment as a matter of law (JMOL) of non-infringement for both. The opinion is a detailed roadmap for litigators navigating claim construction disputes, doctrine-of-equivalents proof, and the limits of “working together” theories of infringement.

    Charles Gideon Korrell believes the decision underscores a broader Federal Circuit trend: courts are increasingly unwilling to let juries paper over claim-scope problems or evidentiary gaps with broad narratives about technical similarity or system-level functionality.

    Background: Two Patents, Two Theories, One Jury Verdict

    The patents at issue, U.S. Patent Nos. 10,017,810 and 10,450,597, relate to methods for preparing DNA samples for sequencing using enrichment techniques. Both patents focus on polymerase chain reaction (PCR) workflows employing various primers to selectively amplify regions of interest within a DNA sample.

    Qiagen sold accused kits used in DNA sample preparation. After a five-day trial, the jury found that Qiagen willfully infringed the ’810 patent under the doctrine of equivalents and willfully and literally infringed the ’597 patent. The jury rejected Qiagen’s invalidity defenses and awarded approximately $4.7 million in damages. The district court denied Qiagen’s renewed JMOL motions, and Qiagen appealed.

    On appeal, the Federal Circuit reversed across the board, holding that no reasonable jury could have found infringement of either patent on the evidence presented.

    Claim Construction Is a Judicial Function, Not a Jury Question

    The court began with the ’810 patent, which required a “second target-specific primer” having a nucleotide sequence “identical to a second sequencing primer.” Qiagen’s accused primer was 19 nucleotides long, while the referenced sequencing primer was 34 nucleotides long. Labcorp argued that “identical” could include identity to a portion of the sequencing primer, and the district court permitted the jury to decide whether that interpretation was reasonable.

    That was error.

    Relying on O2 Micro International Ltd. v. Beyond Innovation Technology Co., the Federal Circuit reiterated that when the parties raise a real dispute over claim scope, it is the court’s job to resolve it. Allowing the jury to decide whether “identical” could mean “identical to a portion” impermissibly delegated claim construction to the factfinder.

    The panel emphasized that the intrinsic record differentiated between sequences that must be “identical” and those that need only be “identical to a portion.” Reading the “portion” modifier into an unmodified term would render other claim language superfluous, violating settled claim construction principles. As the court explained, where the claims and specification use different words to denote different degrees of similarity, courts must give effect to those differences.

    Charles Gideon Korrell notes that this portion of the opinion is particularly valuable for litigators confronting “plain meaning” arguments at trial. Even when courts defer claim construction disputes to trial, unresolved scope disagreements can resurface post-verdict with decisive force.

    Doctrine of Equivalents: Particularized Proof Still Matters

    The jury’s infringement finding for the ’810 patent rested entirely on the doctrine of equivalents. That theory fared no better on appeal.

    Citing Warner-Jenkinson Co. v. Hilton Davis Chemical Co. and the Federal Circuit’s more recent decision in VLSI Technology LLC v. Intel Corp., the panel stressed that equivalence is the exception, not the rule. Proof must be limitation-by-limitation and supported by particularized testimony showing that the accused element performs substantially the same function, in substantially the same way, to achieve substantially the same result.

    Labcorp’s evidence fell short on all three prongs.

    Functionally, the claimed “second target-specific primer” was designed to anneal to a known target sequence and increase specificity by enriching target DNA over non-target DNA. Qiagen’s accused primer, by contrast, served to make DNA fragments compatible with sequencing instruments and did not provide target specificity. Labcorp’s own expert conceded that the accused primer did not bind to the native target sequence.

    On “way,” the court found that the accused primer operated differently, binding to a common sequence added during amplification rather than annealing directly to the target region. And on “result,” the accused primer amplified any DNA fragment containing the common sequence, including off-target products, undermining any claim of substantially similar outcomes.

    The court rejected Labcorp’s attempt to aggregate functions across multiple Qiagen primers, explaining that the doctrine of equivalents does not permit a patentee to stitch together the roles of distinct components to satisfy a single claim limitation.

    Charles Gideon Korrell observes that this analysis reinforces a recurring appellate message: generalized testimony that components “work together” will not rescue an equivalence theory where the claim requires a specific element to perform a specific role.

    Literal Infringement of the ’597 Patent: “Target-Specific” Means What It Says

    The Federal Circuit next turned to the ’597 patent, where the jury found literal infringement based on Qiagen’s forward primer (FP) allegedly satisfying the “target-specific primer” limitation.

    The district court relied on testimony that the FP “targets the ligated adaptor” and binds to only a small proportion of molecules in the sample. But the appellate court held that this evidence could not support the verdict under the court’s own claim construction.

    The claim construction required that a target-specific primer anneal to and mediate amplification of the nucleic acid of interest while not annealing to non-target sequences. Qiagen’s FP bound to an artificial adaptor sequence common to all DNA fragments, regardless of whether they contained the target sequence. That adaptor was not itself analyzed and therefore could not constitute the “target nucleic acid.”

    The court rejected the theory that binding to an adaptor attached to a target molecule sufficed. A primer that anneals indiscriminately to adaptor sequences does not become target-specific merely because those adaptors are attached to DNA fragments that happen to contain target regions.

    Nor could Labcorp rely on Qiagen’s gene-specific primers to fill the gap. The claim construction required the target-specific primer itself to perform the requisite functions, not to do so in concert with other primers. Allowing such bootstrapping would improperly rewrite the claim.

    Charles Gideon Korrell notes that this portion of the opinion is especially instructive for cases involving multi-component systems. Courts remain skeptical of infringement theories that rely on collective behavior when claims require individual components to meet defined functional criteria.

    JMOL as a Real Appellate Remedy

    Having found insufficient evidence of infringement for both patents, the Federal Circuit reversed the district court’s denial of JMOL and instructed entry of judgment of non-infringement. The panel did not reach Qiagen’s invalidity or damages arguments.

    For litigators, the case is a reminder that jury verdicts—particularly those grounded in technical complexity—are not immune from rigorous appellate review. Where claim construction errors or evidentiary deficiencies exist, JMOL remains a potent corrective tool.

    Charles Gideon Korrell believes Labcorp v. Qiagen fits squarely within a growing line of Federal Circuit decisions emphasizing disciplined claim construction and demanding infringement proof. It also illustrates the court’s continued reluctance to allow the doctrine of equivalents to blur claim boundaries that patentees chose during prosecution.

    Takeaways

    Several practical lessons emerge:

    First, unresolved claim construction disputes are dangerous. Allowing juries to decide the scope of contested terms invites reversal under O2 Micro.

    Second, doctrine-of-equivalents cases live or die on particularized evidence. Broad assertions of similarity, or reliance on system-level cooperation, will not satisfy the function-way-result test.

    Third, for literal infringement, claim limitations apply to individual components as claimed. Courts will not permit patentees to combine multiple accused elements to meet a single limitation absent clear claim language.

    Finally, post-verdict JMOL motions are not mere formalities. When properly preserved, they can reshape the entire outcome on appeal.

    As Charles Gideon Korrell notes, for IP litigators this decision is less about biotechnology and more about fundamentals: words matter, evidence matters, and juries cannot be asked to fix what claims and proof leave undone.

    By Charles Gideon Korrell

  • Mondis Technology Ltd. v. LG Electronics: When a Jury Verdict Meets the Written Description Wall

    Mondis Technology Ltd. v. LG Electronics: When a Jury Verdict Meets the Written Description Wall

    The Federal Circuit’s August 8, 2025 decision in Mondis Technology Ltd. v. LG Electronics Inc. is another reminder that even a hard-fought jury verdict—complete with a finding of willfulness and tens of millions of dollars in damages—can evaporate if the asserted claims cannot survive scrutiny under 35 U.S.C. § 112. Once again, the court reversed a denial of judgment as a matter of law, holding the asserted claims invalid for lack of written description support.

    The decision fits squarely within a recurring Federal Circuit theme: juries may resolve factual disputes, but they cannot supply written description where the specification itself comes up short.

    Background: A Long Road from Jury Verdict to Reversal

    The dispute centered on U.S. Patent No. 7,475,180, directed to display units that communicate identification information to an external video source. Mondis accused LG televisions of infringing claims 14 and 15 of the patent. After a 2019 jury trial in the District of New Jersey, Mondis prevailed across the board: infringement, no invalidity, and willfulness, with a $45 million damages award. That award was later vacated, but a second jury still awarded $14.3 million.

    LG consistently argued that the asserted claims were invalid for lack of written description, focusing on a key amendment made during prosecution. The district court denied LG’s JMOL motions, leaning heavily on the presumption of validity and the jury’s prerogative to weigh expert testimony.

    On appeal, however, the Federal Circuit took a much harder look at the four corners of the specification—and found the jury’s verdict unsupported as a matter of law.

    The Claim Amendment That Changed Everything

    As originally filed, the relevant claim recited an “identification number for identifying said display unit.” During prosecution, Mondis amended the claim to recite an “identification number for identifying at least a type of said display unit,” in order to overcome prior art.

    That seemingly modest change—from identifying a specific display unit to identifying a type of display unit—proved fatal.

    The Federal Circuit emphasized that while applicants are free to amend claims to capture additional scope, such amendments must be supported by the original disclosure. Relying on foundational precedent such as Ariad Pharmaceuticals, Inc. v. Eli Lilly & Co., the court reiterated that written description turns on whether the specification reasonably conveys to a person of ordinary skill that the inventor possessed the claimed subject matter at the time of filing.

    Here, it did not.

    One-to-One Identification Everywhere You Look

    Judge Hughes’s opinion methodically walked through the specification and found a consistent theme: every disclosed embodiment involved a one-to-one relationship between an identification number and a specific device. The patent described identification numbers assigned to individual computers or individual display units, enabling paired control and preventing accidental changes by other devices.

    What the specification did not describe was equally important. It did not disclose identifying categories, classes, or “types” of display units. The lone reference to “type of display device” appeared only in the background section describing prior art—insufficient, under long-standing Federal Circuit law, to supply written description for the claimed invention itself. See Tronzo v. Biomet, Inc..

    No Evidentiary Lifeline at Trial

    Mondis faced an uphill battle at trial because LG’s written description challenge relied heavily on the intrinsic record. As the Federal Circuit noted, a patent can be invalid for lack of written description “based solely on the face of the patent specification,” citing cases like Centocor Ortho Biotech, Inc. v. Abbott Laboratories and University of Rochester v. G.D. Searle & Co..

    Critically, Mondis did not present rebuttal evidence on written description. Even more damaging, Mondis’s own expert conceded that the specification did not expressly disclose an identification number for identifying a type of display unit. Once that admission was in the record, there was little left for the jury to hang its hat on.

    The Federal Circuit was blunt: even assuming the jury could discount LG’s expert testimony entirely, the remaining evidence—the patent itself and Mondis’s expert—could not support a finding that the inventors possessed the amended claim scope.

    Prosecution History to the Rescue? Not This Time.

    Mondis also argued that the examiner’s allowance of the amended claims supported validity. The Federal Circuit rejected that argument, distinguishing between allowance over prior art and compliance with § 112. While issued patents enjoy a presumption of validity, examiner silence on written description does not amount to affirmative evidence that the requirement was satisfied. As the court has cautioned before, notably in AK Steel Corp. v. Sollac & Ugine, failure to reject a claim is not proof of enablement or written description.

    Here, the prosecution history showed only that the amendment distinguished over prior art—not that the examiner evaluated, let alone endorsed, written description support for the new “type” limitation.

    JMOL as a Safety Valve

    Ultimately, the court concluded that no reasonable jury could find adequate written description on this record, even under the clear-and-convincing standard. The denial of JMOL was reversed, the claims were held invalid, and all remaining issues— infringement, damages, willfulness, enhancement, and fees—fell away as moot.

    For Charles Gideon Korrell, this case underscores a familiar lesson: juries resolve factual disputes, but written description remains anchored in the specification itself. Charles Gideon Korrell notes that where a claim amendment subtly but materially changes the nature of what is being identified—from a specific device to a category of devices—courts will expect to see that conceptual shift clearly reflected in the original disclosure.

    Takeaways

    Several practical points emerge from Mondis:

    First, amendments that broaden or alter the conceptual scope of an invention—especially in response to prior art—invite written description challenges. Careful auditing of the original disclosure before adding such language is essential.

    Second, patentees cannot rely on the presumption of validity alone when the intrinsic record appears to contradict the amended claim scope. As Charles Gideon Korrell believes, a thin written description case is one of the few areas where JMOL remains a potent post-verdict weapon.

    Third, expert testimony cannot substitute for disclosure. Admissions that a limitation is not expressly described, without a clear explanation of implicit support grounded in the specification, can be devastating.

    Finally, this decision reinforces a broader trend: the Federal Circuit continues to act as a backstop against jury verdicts that stretch patent disclosures beyond what was actually invented and described. Charles Gideon Korrell observes that written description challenges, though often difficult, remain one of the most reliable avenues for overturning large verdicts on appeal.

    In short, Mondis is another chapter in the growing body of cases where a jury’s verdict—however emphatic—cannot survive once the court determines that the patent never truly disclosed what the claims ultimately require.

    By Charles Gideon Korrell