Expert testimony may not be used to contradict the meaning of a claim term as set forth in the intrinsic evidence, even where the claim term is definitionally elastic. Claimed recitations to terms of approximation such as “substantially” and “generally” are used to avoid strict numerical boundaries to the specified parameter, and will be upheld where the unambiguous meaning can be determined from the intrinsic evidence.
In Playtex, Inc. v. Procter & Gamble Co., No. 04-1200 (Fed. Cir. March 7, 2005), the federal circuit vacated a grant of summary judgment of noninfringement to Procter & Gamble (“P&G”) based on an erroneous claim construction.
Playtex’s ‘178 patent is directed to a tampon applicator having a tapered end with diametrically opposed, flattened surfaces. Playtex sued P&G for infringement of its ‘178 patent, based on P&G’s commercialization of its “Tampax Pearl Plastic” product which contains an applicator whose finger grip area is continuously curved. In construing “substantially flattened surfaces” in Claim 1 to mean “opposing surfaces with a curvature less than either the barrel or transitional portion of the prior art,” the court reasoned that the ‘178 patent’s preferred embodiment was excluded. The district court then resorted to the intrinsic evidence, found it to be ambiguous, and relied on testimony by P&G’s expert in concluding that the substantially flattened language would require opposed surfaces that are flat within a geometric, manufacturing tolerance. The court awarded summary judgment of noninfringement to P&G.
On appeal, the federal circuit held it was error for the district court to have relied on extrinsic expert evidence that contradicted the meaning of the term as found in the intrinsic evidence. The plain language of the claimed recitation to “substantially flattened” required neither a perfectly flat surface nor one that is flat within a manufacturing tolerance. The ‘178 patent did not describe the tampon applicator at the level of a manufacturing specification, and the district court’s reliance on expert testimony for this interpretation was erroneous. It was also error to have interpreted the recitation to “substantially flattened” to require a strict numerical limitation. Nothing in the specification or the prosecution history defined substantial in terms of a numerical value; rather, substantial was used as a point of comparison. Relying on the figures to support a numerical limitation, the district court improperly limited claim 1 to a preferred embodiment.
The case presents a rare glimpse of a contest between expert testimony and intrinsic evidence as competing source materials for claim interpretation. Equally intriguing is the endorsement of intrinsic support for terms of approximation, especially by an author who recently, in Merck v. Teva (Fed. Cir. Jan. 28, 2005), discarded the intrinsic definition of “about” in favor of a dictionary definition meaning “approximately.”
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