The Court of Appeals for the Federal Circuit, in Speedtrack, Inc. v. Amazon.com., Inc., Case No. 20-1573 (Fed. Cir. 2021), affirmed the district court’s holding that statements made by the patentee were a clear and unmistakable disavowal of claim scope. By distinguishing the invention from a prior art reference on the basis that the prior art reference requires a “hierarchical” relationship between values and fields (e.g., each value must correspond to an associated field type), the patentee has surrendered such construction for its patent. The doctrine of prosecution disclaimer ensures that claims are not “construed one way in order to obtain their allowance and in a different way against accused infringers.”
The full opinion is here.