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By Saketh Meka, Law Clerk

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In&nbsp;Genuine Enabling Technology LLC v. Sony Group Corporation, decided February 19, 2026, the United States Court of Appeals for Federal Circuit&nbsp;<a href="https://www.cafc.uscourts.gov/opinions-orders/24-1686.OPINION.2-19-2026_2649632.pdf">affirmed</a>&nbsp;a district court’s&nbsp;<a href="https://assets.law360news.com/1817000/1817357/https-ecf-ded-uscourts-gov-doc1-04316365780.pdf">grant of summary judgment</a>&nbsp;of non-infringement: a ruling that turned on the partial exclusion of plaintiff’s expert testimony under&nbsp;Daubert. The decision provides a useful framework for how courts evaluate expert testimony on structural equivalence for means-plus-function patent claims and illustrates the consequences when an expert’s analysis fails to grapple with the full scope of a disclosed structure. This article examines the case’s procedural history, the reasoning of both the District Court, Judge Mitchell Goldberg (R) now Sr. Counsel at Blank Rome and the precedential affirmance of the Federal Circuit.&nbsp;

The Patent and Accused Products

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The patent at issue,&nbsp;<a href="https://patents.google.com/patent/US6219730B1/en">U.S. Patent No. 6,219,730</a>, addressed a familiar problem in computing: the efficient transmission of multiple data streams over a single communication link. The key claim element was an “encoding means for synchronizing” two input data streams. The patent specification depicted this structure as a logic circuit, labeled “block 34,” containing several specific components working in concert: a data selector that alternates between streams, a clock generator producing a bit-rate clock, an oscillator, and signal pathways leading to a codec. Genuine Enabling Technology (“GET”) alleged that Sony’s PlayStation controllers and consoles infringed this structure through their Bluetooth modules.&nbsp;

Because the patent employed means-plus-function language under 35 U.S.C. §&nbsp;112(f), GET could not simply show that Sony’s Bluetooth module performed the same function. Instead, GET had the burden to prove that the module in the PlayStation controller was either identical or “structurally equivalent” to the specific structure disclosed in the patent. Under the well-established “function-way-result test,” structural equivalence demands more than shared purpose: the accused structure must perform the same function, in substantially the same&nbsp;way, to achieve substantially the same&nbsp;result.&nbsp;

The District Court’s Daubert Ruling

The outcome of the case hinged on whether GET’s expert, Dr. Fernald, had supplied a sufficiently rigorous analysis to support his conclusion that the accused PlayStation Bluetooth module was structurally equivalent to the patent’s block 34. Dr. Fernald opined that the Bluetooth module was equivalent to the patent’s structure because both synchronize data to a “bit-rate clock,” a timing signal that coordinates data transmission. But Sony’s&nbsp;Daubert&nbsp;challenge exposed a critical flaw in that reasoning: Dr. Fernald had explained only that synchronization&nbsp;must occur&nbsp;for Bluetooth to function, not&nbsp;how&nbsp;the Bluetooth module actually accomplishes it.&nbsp;

The district court granted Sony’s&nbsp;Daubert&nbsp;motion in part, excluding Dr. Fernald’s ultimate conclusion that the accused Bluetooth module was equivalent to block 34. The Court found Dr. Fernald’s analysis fatally incomplete. His expert report originally described the roles of the data selector and codec in the synchronization process, components that, alongside the bit-rate clock, comprised the patented structure. But at the&nbsp;Daubert&nbsp;hearing, GET’s argument narrowed, focusing exclusively on the bit-rate clock while abandoning the other components. The district court identified this unexplained retreat as the central problem. If the data selector and codec “play roles” in synchronization, as Dr. Fernald had originally stated, why could they suddenly be disregarded when comparing the patented structure to the accused product? The Court found no answer in the record.&nbsp;

To crystallize the problem, the district court offered an analogy. Consider a paperclip and a paperweight: both apply pressure to paper, but one uses bent metal while the other relies on gravity. To say that the “way” both devices work is by “applying pressure to paper” is to describe the function, not the mechanism. It begs the very question the function-way-result test is designed to answer: are the omitted details, bent metal versus gravity, insubstantial, or do they represent fundamentally different approaches? Dr. Fernald’s assertion that both structures “use a bit-rate clock” operated at a similarly unhelpful level of abstraction, too high to permit any meaningful comparison of how the two structures actually work. The Court also identified a fundamental evidentiary gap: GET and Dr. Fernald had never obtained or analyzed schematics of the accused Bluetooth modules.&nbsp;

With Dr. Fernald’s equivalence conclusion excluded, Sony moved for summary judgment, which the district court granted. The district court found that GET had pointed to essentially no information regarding how the accused Bluetooth module operates other than that a bit-rate clock is involved somehow. Identifying a single shared feature, whether pressure or a bit-rate clock, cannot substitute for the rigorous comparison that was needed.&nbsp;

The Federal Circuit affirmed Judge Goldberg’s grant of summary judgment. Writing for the panel, Judge Chen agreed with the district court that GET and Dr. Fernald had failed to account for many of the elements in block 34 in their infringement analysis. Citing&nbsp;Traxcell Technologies&nbsp;and&nbsp;Dawn Equipment Co. v. Kentucky Farms Inc., the court reiterated that a patentee fails to meet its burden when its expert neglects to address a significant fraction of the disclosed structure.&nbsp;

The Federal Circuit noted GET’s failure to explain why it was permissible to discard significant portions of the disclosed structure. As the Federal Circuit emphasized, where a patentee elects to focus its equivalence analysis on something less than the whole disclosed structure, “the patentee has an obligation to meaningfully explain why it is permissible to discard the other elements.”

The Federal Circuit also highlighted a practical failure that compounded GET’s argument. GET had served subpoenas for Bluetooth module schematics on the final day of fact discovery and was denied an extension, meaning Dr. Fernald never actually examined the PlayStation Bluetooth module’s internal design. To bridge this evidentiary gap, Dr. Fernald argued that all logic designs performing synchronization to a bit-rate clock are structurally equivalent. The Federal Circuit found this opinion conclusory and cautioned that accepting such a broad theory would collapse the function-way-result test into a mere function-result test, eviscerating the “way” prong entirely.&nbsp;

This case serves as an important reminder for patent litigators that they must fully comply with&nbsp;Daubert&nbsp;standards when choosing and preparing an expert witness. Motions to exclude expert testimony are rarely granted. This ruling represented one of Judge Goldberg’s very few&nbsp;Daubert&nbsp;exclusions in seventeen years on the district court bench. But when&nbsp;Daubert&nbsp;motions do succeed, the consequences can be outcome determinative, as this case demonstrates.

Expert testimony must be helpful to the factfinder, not merely conclusory. An expert’s opinions are not admissible simply because the expert asserts them to be true. Courts require far more than an expert’s assertion: their opinions must be supported by clear and reasoned analysis. An expert must have good grounds for his or her beliefs, and those grounds must be apparent from the record.

Here, Dr. Fernald’s failure to explain why omitted structural elements were insubstantial, coupled with his inability to examine the accused products’ internal design, rendered his equivalence conclusion inadmissible. Once excluded, GET had no remaining evidence to survive summary judgment. The lesson is clear. Practitioners should ensure their experts engage rigorously with both the claimed structure and the accused device, providing reasoned explanations for every analytical choice. Without that foundation, even the strongest case may collapse under&nbsp;Daubert&nbsp;scrutiny.

This article is one in a series of articles written for <a href="/news-and-events/blank-rome-appellate-insights-winning-appeal-march-2026/" id="39504">Blank Rome Appellate Insights: Winning on Appeal - March 2026</a>.

Federal Circuit Affirms Summary Judgment for Sony in $500 Million PlayStation Patent Dispute: Lessons from a Deficient Expert Report

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Federal Circuit Affirms Summary Judgment for Sony in $500 Million PlayStation Patent Dispute: Lessons from a Deficient Expert Report

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