Lydall Thermal/Acoustical, Inc. v. Federal-Mogul Corp. (Fed. Cir. Sept. 8, 2009) (nonprecedential)

In this case, the district court (Eastern District of Michigan) entered final judgment of noninfringement pursuant to a stipulation by the parties that allowed the plaintiff Lydall to appeal the district court's claim constructions of any of thirteen terms. Lydall appealed the construction of two terms. The Federal Circuit, in an opinion by Judge Lourie, affirmed the district court's claim construction of these two terms. This case provides a good example of how statements in a patent specification consistently describing "the present invention" in a particular way can potentially lead to narrow claim constructions.

The disputed claims at issue are directed to flexible insulating shields that can be used for thermal and acoustic insulation. At issue on appeal was the construction of two claim terms: "fibrous batt of fibers" and "tufts of fibers." The district court construed "fibrous batt of fibers" to mean "a composite batt having a layer of insulating fibers sandwiched between layers of binding fibers" as the district court found that "there is not a hint in the specification that the batt can be a single homogenous layer" and the specification consistently described the batt has having an insulating layer between binding layers. The district court constructed "tufts of fibers" to mean "clusters of binding fibers which have been intentionally needle-punched on a downstroke and which extend beyond an opposite surface of the batt" as the court found "the specification and the drawings made clear that 'tufts' had to extend beyond the exit or second side of the needle and that the patent made no mention of a tuft appearing on the entry or first side of the needle."

For the term "fibrous batt of fibers", Lydall argued that the term should not be limited to multi-layer batts but should also include single-layer batts, citing to the claim language and various portions of the specification and file history. The Federal Circuit disagreed, stating that the patent specification "discloses a single embodiment of the invention" and "[a]lthough Lydall is correct in saying that the claim language 'fibrous batt of fibers' does not, in isolation, suggest a layered batt, Lydall's arguments completely ignore the consistent use of the term 'batt' in the specification." The specification "identifies a three-layered batt as 'the present invention' ... [and] repeatedly describes the batt as having an insulating layer disposed between two binding layers." Citing its prior Honeywell decision, the Federal Circuit explained that "when a patentee consistently describes one embodiment as 'the present invention,' 'the public is entitled to take the patentee at his word.'" Therefore, the Federal Circuit affirmed the district court's construction of this claim term.

For the term "tufts of fibers", Lydall argued that both the parties and the district court agreed that "tufts of fibers" are "clusters of fibers" and there was nothing in the specification or file history to indicate that this term should be given anything other than its ordinary and customary meaning. Again, the Federal Circuit disagreed. Stating that while Lydall was correct that the ordinary meaning of "tufts" is "clusters," a court "will adopt an alternative meaning 'if the intrinsic evidence shows that the patentee distinguished that term from prior art on the basis of a particular embodiment, expressly disclaimed subject matter, or described a particular embodiment as important to the invention.'" (quoting from CCS Fitness). Finding that "[e]very time the specification discusses how to create the tufts of fibers, it states that the tufts form on the opposite side of the needle's entry point ...[t]he specification identifies a batt with tufts on the upper and lower surfaces as 'the present invention' ... [and] the specification consistently describes the batt with tufts on both sides", the Federal Circuit affirmed the district court's narrower construct of "tufts of fibers" as "clusters of binding fibers which have been intentionally needle-punched on a downstroke and which extend beyond an opposite surface of the batt."

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