Expert’s Unanswered Questions Do Not Make Claims Indefinite

| Justin J. Gillett


Before: Newman, Lourie, and Dyk. Appeal from the Northern District of California.

Summary: “Unanswered questions” raised about asserted claim terms did not render asserted claims indefinite, in light of the specification, prosecution history, and other relevant evidence.

Nature Simulation Systems brought suit against Autodesk in the Northern District of California for infringement of two patents. The District Court held the claims at issue invalid on the ground of indefiniteness. The District Court recited several “unanswered questions” that Autodesk’s expert raised about terms in the asserted claims. It explained that even if the questions were answered in the specification, the definiteness requirement was not met because the questions were not answered in the claims. Nature Simulation Systems appealed.

The Federal Circuit reversed. It reiterated that claims are to be read and understood in light of the specification, the prosecution history, and other relevant evidence. The Court explained that claims define the metes and bounds of the invention, but they are not intended to repeat the detailed explanations contained in the specification. Here, the Court stated that the specification described relevant prior art that gave clarity to the claim language. The Federal Circuit also noted that the District Court gave no weight to prosecution history showing resolution of an earlier indefiniteness rejection.

Judge Dyk dissented. He argued that the asserted claims should be held invalid as indefinite. Judge Dyk reasoned that the district court properly applied the standard set forth in Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898 (2014), by reading the patent’s claims in light of the specification and prosecution history to determine whether the claims would inform those skilled in the art about the scope of the invention with reasonable certainty. According to Judge Dyk, there was nothing in the record to suggest someone of skill in the art would have understood the language at issue.

Editor: Paul Stewart