New Festo Decision Applied to Preclude Doctrine of Equivalents

In a post-Festo decision, the U.S. Court of Appeals for the Federal Circuit affirmed a district court decision and held a plaintiff patentee was precluded from proving infringement under the doctrine of equivalents due to prosecution history estoppel. Talbert Fuel Systems Patents Co. v. Unocal Corp., Case No. 99-1421 (Fed. Cir. Oct. 28, 2003).

Talbert sued Unocal for the infringement of U.S. Pat. No. 5,015,356 (the '356 patent). The '356 patent is directed to certain reformulated gasolines that reduce emissions while maintaining their performance boundaries. The infringement issue focused on a limitation found in all of the claims requiring the gasoline boiling point to be within of a range of 121°F to 345°F. In the original suit between Talbert and Unocal that reached the Federal Circuit in 2002, the Court relied on the absolute bar established by the first Federal Circuit Festo decision (decided in 2000) to deny Talbert access to the doctrine of equivalents. The Supreme Court's vacatur of that decision led to the remand of this case on the issue of prosecution history estoppel.

As initially filed, claim 1 of the '356 patent recited no temperature range and was rejected based on references that showed gasolines of various hydrocarbon contents and boiling ranges with an upper boiling range of 390°F to 420°F. Unocal's accused fuels had a boiling point range of 373.8°F to 472.9°F. Finding that the "temperature limit was placed in the claims at the examiner's insistence, to distinguish over prior art that … showed hydrocarbon fuels with an endpoint 'within the range of 390°F and about 420°F,'" the Court found there was no "reasonable explanation" of how the "designated endpoint of 345°F is correctly construed to include fuels with endpoints of 373°F and higher" and held that there was no literal infringement.

Talbert requested a remand to the district court for retrial on the issue of infringement under the doctrine of equivalents in view of the Supreme Court's Festo decision, arguing that the 345°F limit does not describe the actual composition that is distilled, at least for carbonated fuels, and would be so recognized by one of skill in the art. Talbert further argued that the evidence would show he did...