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A Nonsensical Result of Claim Construction Does Not Require Court to Redraft Claims

February 20, 2004

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Last Month at the Federal Circuit - March 2004

Judges: Friedman (author), Rader, and Schall

In Chef America, Inc. v. Lamb-Westin, Inc., No. 03-1279 (Fed. Cir. Feb. 20, 2004), the Federal Circuit affirmed a ruling of noninfringement for a patent covering a process for producing a dough product.

The only issue on appeal was the meaning of the claim language “heating the resulting batter-coated dough to a temperature in the range of about 400°F to 850°F.” The district court ruled that this limitation required the dough itself to be heated to that temperature, while the patentee argued that this limitation concerns only the temperature of an oven in which the dough is to be heated.

According to the Federal Circuit, the claim language is clear that the dough is to be heated to the specified temperature. The Court rejected the patentee’s reasoning that such a construction makes little sense because the dough would be burned to a crisp at that temperature range, ruling that even a nonsensical result does not require it to redraft the claims. As written, the Court concluded, the claim unambiguously requires that the dough itself be heated to a temperature range of 400°F to 850°F.

According to the Federal Circuit, the prosecution history suggests that the patentee intentionally used the word “to” rather than “at” in drafting the temperature requirements of the claim. The specification also gave an example of heating the dough “at” a certain temperature, but, in drafting the claims, the applicant chose to use the word “to.” The Federal Circuit construed this as a conscious selection to use the word “to” rather than “at.”