Collateral Estoppel May Not Apply When Claim Interpretation Standards Differ

by | Nov 19, 2025 | Claim Construction

By Thane Bonnett* and Matt Johnson –

In its recent decision in RØDE Microphones, LLC et. al. vs. Zaxcom, Inc., the PTAB declined to apply collateral estoppel based on prior post-grant proceedings because the prior proceedings had applied a different standard of review.  One ground raised by the petitioners was that the patent owner, Zaxcom, Inc., was collaterally estopped from disputing the presence of certain claim limitations and the obviousness of combining two references because these issues had been litigated in previous Inter Partes Reviews (IPRs).  The PTAB disagreed, denying institution of Inter Partes Review on the basis (among other grounds) that collateral estoppel is not appropriate where a first IPR was decided under the Broadest Reasonable Interpretation (BRI) standard and a second IPR concerning the same patent is to be decided under the Phillips standard.

The BRI standard requires pending claims to be given “their broadest reasonable interpretation consistent with the specification.”  This standard is applied by the USPTO when examining claims, and was also used by the PTAB when conducting post-grant proceedings prior to November 13, 2018.  For all petitions filed after that date, the PTAB applies the same claim construction standard as federal courts: the Phillips standard.  This standard, established by the Federal Circuit case Phillips v. AWH Corp, looks for the ordinary and customary meaning of a claim term as it would have been understood by a practitioner of ordinary skill in the art at the effective filing date of the patent application.  The purpose of the PTAB’s transition to the Phillips standard was to produce “greater uniformity and predictability of the patent grant” by applying the same claim interpretation standard in the PTAB as in federal court (83 Fed. Reg. 51,340).

The previous IPRs cited by the petitioners in their collateral estoppel-based grounds were both filed prior to November 13, 2018.  The PTAB applied the BRI standard when interpreting claims in both of these IPRs.  The present matter was filed after 2018, meaning that the PTAB would be applying the Phillips claim construction standard.  As a result of the differing standards, the PTAB held that the patent owner was not precluded from disputing issues decided in the previous IPRs, stating:

Although the Lectrosonics IPRs involved patents from the same family as the ’444 patent, which recite many similar claim limitations, the Lectrosonics IPRs were all decided using the BRI standard, not the Phillips standard.  Thus, no claim interpretation has been made using the standard that will be applied in this case, and the asserted prior art has not been applied to claims interpreted according to the standard in this case.  Accordingly, on this record, we are not persuaded that collateral estoppel applies to any of the disputed issues in this proceeding.

The PTAB then referenced the Federal Circuit’s decision in DDR Holdings, LLC v. Priceline.com LLC, which held that “a party is not collaterally estopped in district court proceedings [which apply the Phillips standard] by the Board’s construction during IPR [which formerly applied the BRI standard].”  The PTAB’s decision applied this holding to a situation where the original BRI claim interpretation and the subsequent Phillips claim interpretation were to occur in the same forum (the PTAB).

Takeaway:  Parties are reminded that a prior proceeding may not create collateral estoppel for a subsequent proceeding if the two proceedings apply different standards.  Specifically, claim construction performed under the BRI standard is unlikely to create issue preclusion for claim construction which is to be performed under the Phillips standard.

* Thane is a member of the New Lawyer’s Group in Jones Day’s Pittsburgh Office.

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Matthew Johnson

Partner at Jones Day
Matt Johnson is one of the Firm's primary contacts on practice before the PTAB. Currently co-chairing the Firm's PTAB subpractice and involved in proceedings at the Board since the first day of their availability in September 2012, Matt regularly represents clients as both petitioners and patent owners at the Board. He further works as an advocate for clients in appeals from Board proceedings at the Federal Circuit.