In the context of remanding a summary judgment ruling of non-infringement, the U.S. Court of Appeals for the Federal Circuit again has held that it is improper to import limitations from a preferred embodiment into the claims absent an express declaration from the patentee. Playtex Products, Inc. v. Procter & Gamble Co. and Procter & Gamble Distrib. Co., Case No. 04-1200 (Fed. Cir., March 7, 2005) (Gajarsa, J.).

Playtex concerned a tampon applicator with a tubular barrel having "two diametrically opposed, substantially flattened surfaces" and a slideable plunger. The opinion focuses on two claim terms: "substantially flattened surfaces" and "means for limiting the movement of [the] plunger."

The district court determined "substantially flattened surfaces" ordinarily means "surfaces with a curvature less than either the barrel or the transitional portion of the prior art," but also that this ordinary meaning precludes completely flat surfaces. Noting that the patent’s preferred embodiment had completely flat surfaces, the court concluded that the intrinsic evidence was ambiguous and therefore relied on an expert in plastic manufacturing to construe the term to mean "flat within a geometric, manufacturing tolerance."

The Federal Circuit held that the ordinary meaning of "substantially flattened surfaces" was unambiguous in view of the intrinsic evidence and that it could include both flat surfaces and surfaces that are simply flatter than they had originally been. Thus, the district court erred in relying on extrinsic evidence to construe the term and improperly limited the claims to flat surfaces described in the preferred embodiment. The Federal Circuit also faulted the district court’s construction for incorrectly introducing a numerical tolerance to the flatness of the surfaces, which contradicts the purpose of using the modifier "substantially."

With respect to the "means for limiting" the movement of the plunger (a §112, 6 claim element), the patent holder, Playtex, argued that the corresponding structure shown in the patent drawings (showing a preferred embodiment having a lip structure at both ends of the plunger) properly defined the scope of the claims. The district court rejected this argument and instead referred to the written description, which described the corresponding structure more broadly as "a curved-shaped ‘lip’ or equivalent structure on at least one, and preferably both, ends of the plunger."

The Federal Circuit affirmed on this point, agreeing that the corresponding structure should not be limited to the single embodiment depicted in the figures, but should be broadly construed in accordance with all structures disclosed in the written description.

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