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Plain Meaning and Prosecution History Limit Literal Scope of Claim and Estop Infringement

January 08, 2002

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Last Month at the Federal Circuit - February 2002

Judges: Newman (author), Michel, and Rader

In Talbert Fuel Systems Patents Co. v. Unocal Corp., No. 99-1421 (Fed. Cir. Jan. 8, 2002), the Federal Circuit affirmed a district court’s grant of SJ of noninfringement against Talbert Fuel Systems Patents Company (“Talbert”) and dismissal of Talbert’s requested interference proceeding.

Talbert owns U.S. Patent No. 5,015,356 (“the ‘356 patent”), which is directed to gasoline formulations containing middle-end hydrocarbons substantially free of both high-end and low-end hydrocarbons except for a small amount of low-end hydrocarbons added as a priming agent. Claim 1 of the ‘356 patent describes Talbert’s gasoline formulation and further provides a boiling range of between 121°F and 345°F at 1 atmosphere of pressure.

The lower court had construed claim 1 as limited to formulations having a final boiling point of 345°F and granted Unocal Corporation’s (“Unocal”) motion for SJ, finding no infringement either literally or under the DOE.

On appeal, Talbert argued that the district court had erred in its interpretation of the boiling point range because due to imprecise, yet standard refining techniques, high-end hydrocarbons could be present in the mixture that would, in turn, lead to an increased boiling point. Further, Talbert argued that the term “consisting essentially of C6-C10” hydrocarbons in claim 1 means that some hydrocarbons outside of that range may be present.

In analyzing the scope of the claims, the Federal Circuit focused on comments made by Talbert during prosecution of the ‘356 patent where Talbert had stated that 345°F was the “final boiling point” for its formulations. The Court rejected Talbert’s argument that this statement was made merely to help show that the newly added claim term “paraffinic hydrocarbons” was not new matter under 35 U.S.C. § 112. The Court ruled that during prosecution Talbert had stressed that 345°F was the final boiling point and relied on this final boilingpoint limitation in distinguishing several prior art references. As such, Talbert was precluded from reading the literal scope of its claims on a boiling point above the 345°F level.

The Court further ruled that because Talbert had distinguished its claims from prior art based on this 345°F limitation, Talbert was now estopped from expanding the reach of its claims under the DOE under Festo.

Talbert also argued that the lower court had erred in not declaring an interference proceeding. According to Talbert, in 1989, it had disclosed its invention to Unocal, who then evaluated Talbert’s invention but expressed no interest in it. About a year later, Unocal filed a patent application that later issued as U.S. Patent No. 5,288,393 (“the ‘393 patent”). Claim 81, the claim at issue regarding Talbert’s interference request, was directed to an unleaded gasoline fuel. Talbert had requested that the district court issue a declaration of priority of invention under 35 U.S.C. § 291 for Talbert. The district court had denied Talbert’s request, stating that the inventions were not the same because Unocal’s patent did not state a similar boiling point and the ‘393 patent’s limitations on olefin and paraffinic content were also distinguishing. On appeal, Talbert had argued that the inventions were the same based on characteristics, even though the interfering claims recited different limitations.

The Court agreed with Talbert’s legal interpretation, but found Talbert’s evidence wanting. In affidavits provided to the district court, Talbert argued that a gasoline in accordance with claim 1 of the ‘356 patent would have the same characteristics of claim 81 of the ‘393 patent. The Court found that the affidavits did not support this opinion and they also failed to respond to Unocal’s position that its claimed fuel had an octane value of 92, whereas Talbert’s fuel had an octane of 84.3 and required additives to reach 92. Thus, according to the Court, the inventions were not the same and even if one skilled in the art would have known how to raise the octane level in Talbert’s fuel into one of a higher octane such as in claim 81, that would not have met the inherency requirement in the context of obviousness. Accordingly, the Court affirmed the district court’s decision, declining to declare an interference.