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In the high-stakes world of patent litigation, accused infringers often pursue parallel strategies in district court and at the Patent Trial and Appeal Board ("PTAB"). But what happens when those strategies directly contradict each other? Revvo Technologies just found out the hard way.
On November 3, 2025, the USPTO Director took the extraordinary step of sua sponte (meaning nobody asked him to do it) vacating a PTAB decision that had granted institution of an inter partes review ("IPR") of a patent owned by one of Revvo's competitors, Cerebrum Sensor Technologies. Revvo Techs., Inc. v. Cerebrum Sensor Techs., Inc., IPR2025-00632, Paper 20. The Director's issue? Revvo couldn't explain why it was taking opposite positions on claim construction in the IPR versus the parallel district court litigation. His message was clear. The USPTO won't tolerate unexplained gamesmanship between forums.
The Litigation Background: More Than Just Tire Pressure
The dispute began when Cerebrum Sensor Technologies and its affiliate Tire Stickers LLC sued Revvo in Delaware federal court for allegedly infringing three patents related to advanced tire sensor technology. Cerebrum Sensor Techs., Inc. v. Revvo Techs., Inc., Case No. 1:24-cv-00245-JLH, Doc. 1 (D. Del. filed Feb. 23, 2024). While the complaint asserted U.S. Patent Nos. 10,137,741; 11,124,027; and 11,835,421, it's the '421 patent that became the centerpiece of this procedural drama.
These aren't your grandfather's manual tire pressure gauges, or even the basic Tire Pressure Monitoring System ("TPMS") sensors that became mandatory in vehicles after the TREAD Act of 2000. TPMS sensors simply alert drivers when tire pressure drops below a certain threshold. Cerebrum's patented technology promises something far more sophisticated: real-time detection of imminent tire blowouts, continuous tread depth monitoring, and tire alignment tracking. For fleet managers, this means replacing tires at the optimal time—maximizing safety while minimizing costs. For the emerging autonomous vehicle market, it could mean the difference between a vehicle safely pulling over before a tire failure versus a highway emergency.
The Patent's Key Innovation: No More Potting
The '421 patent, issued December 5, 2023, addresses a specific engineering challenge in tire sensor design. Traditional tire-mounted sensors face a brutal environment—spinning at highway speeds, exposure to temperature extremes, and constant vibration. To keep the sensitive electronics in place, manufacturers typically use "potting" materials—essentially encasing the electronics in silicone or epoxy compounds. Think of it like embedding your smartphone in rubber cement and hoping it survives.
The '421 patent takes a different approach, using mechanical features within the sensor housing to secure the electronics without any potting materials. As the patent specification explains: "A feature of sensor assemblies as disclosed herein is that they do not use or require the use of any such coating or filling agents or materials for any fixturing of the electrical sensor device 40 within the internal cavity 38." '421 Patent at col. 13:60-64. This could mean easier manufacturing, better reliability, and lower costs.
The IPR Flip-Flop
Four months after being sued, Revvo filed its IPR petition challenging the '421 patent's validity. But here's where things got interesting. Instead of maintaining its narrow claim constructions from the district court, Revvo simply "accept[ed] Patent Owner's proposed constructions from the underlying district court litigation for the purposes of this Petition." IPR2025-00632, Paper 1 at 9-10.
Why the about-face? The tactical reason is obvious. In the IPR, Revvo needed to prove the claims were invalid over the prior art. Broader claims are easier to invalidate—they cover more ground, making it more likely that prior art references will anticipate or render them obvious. By adopting Cerebrum's broader constructions, Revvo improved its chances of invalidating the patent.
The Illusion of Agreement
At first blush, Revvo's approach in the IPR seemed almost conciliatory. Rather than fighting over claim construction—often a lengthy and expensive battle within an IPR—Revvo simply accepted Cerebrum's proposed constructions from the district court action. No disputes. No additional briefing. No complication for the Board.
The Board's initial response was predictable. When Cerebrum complained about gamesmanship, the Board essentially shrugged. How could Cerebrum object to Revvo adopting Cerebrum's own proposed constructions? As the Board noted, Cerebrum "does not dispute any of the proposed interpretations set forth in the table." IPR2025-00632, Paper 13 at 8. From the Board's perspective, Revvo had actually simplified matters by eliminating claim construction disputes entirely. The Board found this sufficient to comply with 37 C.F.R. § 42.104(b)(3)'s requirement to identify how claims should be construed.
But this apparent simplification masked a sophisticated strategy. Revvo wasn't being agreeable—it may well have been gaming the system. By maintaining that the claims were indefinite or extremely narrow in district court while simultaneously using Cerebrum's broader constructions to invalidate those same claims at the PTAB, Revvo was trying to win both ways. If the claims were narrowly construed, Revvo couldn't infringe. If they were broad enough to be infringed, prior art would invalidate them. Heads Revvo wins, tails Cerebrum loses.
The Claim Construction Divide
When parties litigate a patent, one of the first battles involves claim construction—determining what the patent's words actually mean. This process, governed by the Federal Circuit's Phillips standard, can make or break a case. Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). Broader claim language is easier to infringe but also easier to invalidate with prior art. Narrower claims are harder to infringe but more likely to survive validity challenges.
In the Delaware litigation, Revvo pursued a predictable defense strategy: argue the claims are indefinite or should be construed narrowly to avoid infringement. Take the critical term "internal cavity," for example. Revvo argued it was indefinite or, alternatively, meant "a hollow or 'open space' surrounded by and inside (but not included as part of) the housing." Joint Claim Construction Chart, Cerebrum v. Revvo, Case No. 1:24-cv-00245-JLH-SRF, Doc. 84-1 at 6 (D. Del. Jan. 22, 2025). This narrow construction would require the cavity to be completely enclosed on all sides by the housing structure itself.
In contrast, Cerebrum proposed simply "an open space inside of the housing"—a broader construction that doesn't require complete enclosure. Id. The difference matters enormously. Under Revvo's narrow construction, prior art would need to show a cavity completely surrounded by housing walls to anticipate the claim. Under Cerebrum's broader construction, any open space within a housing might suffice.
The distinction became even more critical for how the claims handle sensor attachment. For the term "the electrical sensor device is attached within the internal cavity by one or more surface features," Cerebrum argued for the term's plain and ordinary meaning—which could encompass various attachment methods, potentially including some use of potting materials along with other surface features. Joint Claim Construction Chart, Cerebrum v. Revvo, Case No. 1:24-cv-00245-JLH-SRF, Doc. 84-1 at 21 (D. Del. Jan. 22, 2025).
But Revvo argued for an additional critical limitation: attachment "does not use or require the use of any coating or filling agents or materials to fix and retain the placement position of the electrical sensor device therein." Id. Presumably, this narrow construction would serve Revvo's non-infringement defense in the district court.
But this narrow construction created an obvious problem for Revvo at the PTAB because it would exclude any prior art using potting materials to attach the sensor. And one of Revvo's key prior art references was Yamaguchi-727, which explicitly discloses using silicone potting material to secure its sensor module within the housing.
Under Revvo's district court construction excluding "any coating or filling agents," Yamaguchi-727 couldn't anticipate or render the claims obvious. So when Revvo filed its IPR petition, it abandoned its own narrow construction and instead adopted Cerebrum's broader "plain and ordinary meaning" interpretation. This allowed Revvo to argue that Yamaguchi-727 invalidated the claims—indeed, the Board agreed, finding that Yamaguchi-727's "use of potting material to hold its module 6 in place within its housing 20 meets the requirements of limitation 1b" under the broader construction. IPR2025-00632, Paper 13 at 11-12.
By adopting Cerebrum's construction, Revvo enabled its invalidity position at the PTAB but completely contradicted its non-infringement position in district court—all without offering any explanation for the inconsistency. The Board's preliminary analysis confirmed this strategy could work, finding a reasonable likelihood that Yamaguchi-727 and other prior art rendered the claims obvious precisely because the broader construction encompassed potting-based attachment methods.
The Director Steps In
Just over a month after the Board granted institution, the Director initiated sua sponte review—a relatively rare occurrence that signals something significant is afoot. IPR2025-00632, Paper 19. Two weeks after that, the Director vacated the institution decision entirely.
The Director's intervention reveals a deeper understanding of litigation tactics. What appeared to be procedural efficiency was actually strategic arbitrage—exploiting separate procedures in the two forums without any principled basis for the inconsistency. The fact that Revvo offered no explanation beyond "for purposes of this Petition" exposed the purely tactical nature of the maneuver.
The Director's order cuts to the heart of a fundamental tension in patent litigation strategy. While acknowledging that parties aren't necessarily prohibited from taking different positions in different forums, the Director emphasized that "when a petitioner takes alternative positions before the Board and a district court, that petitioner should, at a minimum, explain why alternative positions are warranted." IPR2025-00632, Paper 20 at 3-4.
Critically, the Director rejected the Board's narrow view that this requirement only applies to means-plus-function disputes under 35 U.S.C. § 112(f). Id. at 4-5. The requirement to explain inconsistent positions applies broadly to all claim construction issues.
The 2018 Rule Change: Context for the Crackdown
To understand why the Director took such decisive action, we need to revisit a major shift in USPTO practice. In 2018, the Office abandoned its longstanding "broadest reasonable interpretation" standard for claim construction, adopting instead the same Phillips standard used in district courts. See Changes to the Claim Construction Standard for Interpreting Claims in Trial Proceedings Before the Patent Trial and Appeal Board, 83 Fed. Reg. 51340 (Oct. 11, 2018).
The stated goal was to harmonize claim construction across forums and provide "greater predictability and certainty in the patent system." Id. at 51342-43. As the Office explained, "Having [PTAB] trial proceedings use the same claim construction standard that is applied in federal district courts and [the International Trade Commission] proceedings also addresses the concern that potential unfairness could result from using an arguably broader standard in [PTAB] trial proceedings." Id.
The Director's order explicitly invokes this policy rationale, stating that allowing unexplained position-switching "does not further the Office's goal" of predictability and certainty. IPR2025-00632, Paper 20 at 4-5.
What Constitutes Sufficient Explanation?
The Director's order provides helpful guidance on what might constitute an acceptable explanation for inconsistent positions. The key example offered is straightforward. If a party advances a narrow construction in the district court and the district court declines to adopt that narrow construction, the party would have sufficient reason for advancing the broader, court-adopted construction in a proceeding before the Board. IPR2025-00632, Paper 20 at 5. This makes practical sense—once a court has spoken on claim construction, a party can reasonably align its PTAB arguments with that judicial determination.
But the Director makes equally clear what won't suffice. Simply stating that you're adopting the patent owner's constructions "for purposes of this IPR" doesn't meet the bar. Id. at 4-5. The Director expects substantive reasons that justify the inconsistency, not mere procedural convenience or tactical advantage. Reading between the lines of the Director's order, a hierarchy of explanations emerges. Explanations grounded in judicial rulings or procedural developments appear most likely to pass muster.
On the other hand, explanations that amount to pure gamesmanship seem destined to fail. Arguing that you need broader constructions to invalidate the patent while simultaneously needing narrower ones to avoid infringement is precisely the kind of having-your-cake-and-eating-it-too approach the Director's order condemns. Boilerplate statements about accepting constructions solely for purposes of the IPR, without more, now clearly fall short of the Director's requirements.
The Director's emphasis on the 2018 rule change harmonizing claim construction standards suggests that explanations should ultimately serve the goal of reaching consistent claim interpretations across forums. Reasons that advance this goal will likely fare better than those that undermine it.
The Immediate Consequences
The Director remanded to the Board with instructions to determine whether Revvo has provided "a sufficient reason why different claim construction positions are warranted." Id. at 5-6. The Board may authorize additional briefing and must issue a decision within 30 days.
For Revvo, this creates a strategic conundrum. Any explanation it offers risks undermining its position in one forum or the other. If Revvo argues its district court positions were merely strategic litigation positions, it may lose credibility at the PTAB. If it argues Cerebrum's constructions are actually correct, that undermines its non-infringement arguments. Ultimately, Revvo will likely be forced to assess odds on its stronger defense and choose between its non-infringement or patent invalidity strategies.
Broader Implications for Patent Practice
This decision sends ripples through the patent litigation community. Parallel district court and PTAB proceedings have become standard practice, with accused infringers routinely pursuing both venues simultaneously. The ability to take different positions in each forum has been a key tactical advantage that practitioners have long relied upon.
The Director's intervention suggests those days may be numbered. While not prohibiting inconsistent positions entirely, the requirement to explain them—and the risk of having an IPR derailed for insufficient explanation—adds a new strategic consideration to parallel proceedings. Patent prosecutors and litigators must now document their reasoning whenever taking inconsistent positions, creating a clear record that goes beyond boilerplate language or assertions of tactical necessity. The days of simply stating "we accept their constructions for IPR purposes" are over.
This new landscape demands early coordination between district court and IPR strategies. Firms can no longer treat these proceedings as independent tracks with separate teams pursuing conflicting theories. Instead, litigation teams must align their approaches from the outset to minimize inconsistencies that will later require explanation. When inconsistencies are unavoidable, the rationale must be substantive and grounded in legitimate procedural developments, not mere tactical advantage.
Perhaps most significantly, the tactical advantages of inconsistent positions must now be weighed against new risks. The possibility of procedural complications, delays, or outright dismissal of an IPR adds a cost to the traditional playbook of arguing narrow constructions in court while seeking broad constructions at the PTAB. For some parties, maintaining consistent positions across forums may now be the safer strategic choice, even if it means accepting trade-offs in one venue or the other.
Conclusion
The smart tire sensor wars have evolved from a straightforward patent dispute into a procedural precedent with implications for every patent case involving parallel proceedings. The Director's message resonates beyond this single case. The USPTO takes its harmonization efforts seriously and expects parties to respect the spirit, not just the letter, of the 2018 rule change.
For Cerebrum, this represents an unexpected procedural victory that could derail or significantly delay Revvo's validity challenge. For Revvo, it's a costly lesson in the risks of trying to have it both ways without adequate justification.
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