Delaware Judges Are Finding Patent Claims Indefinite Post-Nautilus

It has been a little more than a year since the Supreme Court rendered its decision in Nautilus, lowering the standard for finding patent claim terms indefinite. Many commentators at that time predicted the decision would have broad implications for all patent cases where definiteness is at issue. Two recent cases from the District of Delaware demonstrate the accuracy of those predictions as judges in Delaware have seized upon the holding in Nautilus to find patent claim terms indefinite. Practitioners asserting or defending against patent claims would do well to acquaint themselves with the strategies and pitfalls raised by the recent decisions to ensure they provide the best advocacy.

The definiteness requirement for patent claim terms is rooted in 35 U.S.C. § 112, ¶ 2, which provides that "the specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention." The old Federal Circuit standard prior to Nautilus upheld claims as definite so long as they were "amendable to construction" and not "insolubly ambiguous." The Supreme Court altered that standard in Nautilus and now requires "that a patent's claims, viewed in light of the specification and prosecution history, inform those skilled in the art about the scope of the invention with reasonable certainty." Nautilus, Inc. v. Biosig Instruments, Inc., 134 S.Ct. 2120, 2129 (2014). The Federal Circuit has scoffed at the modified standard provided by the Supreme Court, noting that lower courts "may now steer by the bright star of 'reasonable certainty,' rather than the unreliable compass of 'insoluble ambiguity.'" Biosig Instruments, Inc. v. Nautilus, Inc., 783 F.3d 1374, 1379 (Fed. Cir. 2015).

Nonetheless, the holding in Nautilus was recently cited by Judge Sue Robinson in the District of Delaware in finding the claims of 6 patents invalid. Cox Communs. Inc. v. Sprint Communs. Co., No. 12-487-SLR, 2015 U.S. Dist. LEXIS 64252 (D. Del. May 15, 2015). In Cox, the parties disputed whether the claim limitation "processing system" is indefinite. Cox argued that the limitation is indefinite because the structural limitation, "processing system," is only described functionally in the patents. Sprint's expert opined that the patents reference other patents which use the phrase "processing system," demonstrating that a person of ordinary skill in the art would have known with reasonable certainty...