In In Re CSB-System International, Inc., [2015-1832] (August 9, 2016), the Federal Circuit held that the PTAB erred in applying a broadest reasonable interpretation claim construction, instead of a Phillips claim construction, to claims that expired during the course of the ex parte reexamination, but nonetheless affirmed the rejection of claims as obvious under the correct, narrower, standard.

The Federal Circuit said that during reexamination proceedings of unexpired patents, however, the Board uses the broadest reasonable interpretation
consistent with the specification standard, or BRI.  The rationale for permitting
this broader standard in reexaminations is that a patent owner before the Patent and Trademark Office with an unexpired patent may amend claims to narrow their scope, negating any unfairness that may otherwise result from adopting the BRI standard.  However, when an expired patent is subject to reexamination, the traditional Phillips construction standard attaches.

In the instant case, the patent expired after the Examiner issued a final rejection but before consideration of the appeal by the PTAB.  The PTAB applied BRI becaue the patent owner had the opportunity to amend its patent claims while they were pending before the examiner in the reexamination, as the patent had yet to expire.

The Federal Circuit disagreed with the Board’s approach, stating that when a patent expires during a reexamination proceeding, the PTO should thereafter apply the Phillips standard for claim construction, even if this means that the Board applies a different standard than the examiner.

The Federal Circuit held that:

BRI is not a monolithic standard that the Board can use even after a patent expires. Rather, consistent with our prior precedent and customary practice, we reaffirm that once a patent expires, the PTO should apply the Phillips standard for claim construction.