Authored by: Jeremy J. Gustrowsky
The Federal Circuit recently affirmed that a patent owner cannot rely on a post-decision correction of inventorship to reopen final written decisions in inter partes review proceedings. The case centered on whether equitable doctrines like forfeiture can prevent a patent owner from raising new arguments based on a correction of inventorship under 35 U.S.C. § 256, even though such corrections are generally retroactive.
Implicit, LLC owns U.S. Patent No. 7,391,791 and U.S. Patent No. 8,942,252, both originally listing two co-inventors. Sonos, Inc. petitioned for inter partes review of both patents, relying on a prior art reference (U.S. Patent No. 7,269,338, known as “Janevski”) with a filing date of December 11, 2001. Implicit argued that its named inventors had conceived of the inventions and worked with an engineer named Guy Carpenter for implementation before that date, and that Carpenter’s work should inure to the named inventors’ benefit. The Board found Implicit’s evidence insufficient to establish conception and communication of the invention to Carpenter and held all challenged claims unpatentable.
After the Board’s final written decisions issued in September 2019, Implicit requested that the PTO correct the inventorship of both patents to add Carpenter as a co-inventor. The PTO granted the corrections in August 2022. Implicit then argued that because Carpenter was now officially listed as an inventor, his prior work no longer needed to “inure” to anyone’s benefit, and Janevski could be antedated on a new theory. This court remanded the case to the Board for the limited purpose of determining what impact, if any, the certificates of correction had on the final written decisions.
The Board determined that Implicit had forfeited its right to raise this new antedating argument, and the Federal Circuit agreed. The court explained that forfeiture occurs when a party fails to make the timely assertion of a right. Implicit had all relevant inventorship evidence from the outset but chose to present only its original theory. Implicit argued that the Board’s final written decisions “illuminated” Carpenter’s necessary presence as an inventor, but the court distinguished this from situations where a change in claim scope justified a fresh look at inventorship (like in Egenera, Inc. v. Cisco Systems, Inc.). Here, nothing about the claim scope changed. The court also noted concerns about “sandbagging,” where a party pursues one strategy, then seeks to change course only after receiving an unfavorable outcome.
The Federal Circuit further held that forfeiture principles can apply even though Section 256 corrections are generally retroactive and do not impose a specific deadline for correcting inventorship. Citing Stark v. Advanced Magnetics, Inc., the court noted that diligent action is required during a pending proceeding where a change of inventorship could directly affect the outcome. Because Implicit could not adequately explain why it did not seek correction of inventorship or raise alternative theories earlier in the proceedings, the court affirmed the Board’s decision.