Federal Circuit Relies on Prosecution History to Resolve Ambiguous Claim Language

The Court of Appeals for the Federal Circuit, in Univ. of Mass. v. L'Oréal S.A., 36 F.4th 1374 (Fed. Cir. 2022), reversed the district court’s indefiniteness ruling by resolving ambiguous claim language using the intrinsic record. The Court looked beyond the plain and ordinary meaning of a claim limitation with “evident uncertainties” and relied on the specification and prosecution history to resolve this ambiguity. Based on the specification and the prosecution history, the Court vacated the district court’s indefiniteness ruling and remanded the case to the district court to proceed under the new claim construction.