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Patent Claims Found “Insolubly Indefinite,” Hence Invalid

August 26, 2003
Wang, Ningling

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Last Month at the Federal Circuit - September 2003

Judges: Linn (author), Lourie, and Gajarsa

In Honeywell International, Inc. v. International Trade Commission, No. 02-1393 (Fed. Cir. Aug. 26, 2003), the Federal Circuit affirmed the decision of the ITC that the claims at issue were invalid as indefinite under 35 U.S.C. § 112, ¶ 2. Honeywell International, Inc. (“Honeywell”) owns U.S. Patent No. 5,630,976 (“the ’976 patent”), which claims a process for manufacturing a multifilament polyester product called polyethylene terephthalate (“PET”) yarn. Honeywell complained to the ITC that Hyosung Corporation of Seoul, Korea, and Hyosung (America), Inc. (collectively “Hyosung”) were importing PET yarn and PET yarn-containing products that were produced by a process that infringed several claims of the ’976 patent. The ITC found that the asserted claims were invalid as indefinite under 35 U.S.C. § 112, ¶ 2, and that the accused polyethylene terephthalate yarns did not infringe.

Claims 1 and 7 of the ‘976 patent require that solidified yarn must be withdrawn at a certain speed to form a crystalline, partially oriented yarn with a specified crystallinity and a specified melting-point elevation (“MPE”). Similarly, claim 14 requires that, during the process, the yarn exhibit an MPE within a specified range after the hot drawing.

The specification of the ’976 patent defines the term “MPE” as “the difference between the specimen melting point (M.P.) and the melting point (M.P.Q.) of a specimen after subsequent rapid liquid nitrogen quenching of an encapsulated [differential scanning calorimeter (“DSC”)] sample from the melt.” However, the specification does not disclose any method used to prepare the PET-yarn specimen for thermal analysis in the DSC.

The Federal Circuit noted that the calculated MPE for a given sample can vary greatly depending on which method was used to prepare the sample. As of the earliest priority date of the ’976 patent, three PET-yarn sample-preparation methods were published, including (1) the “coil method,” (2) the “cut method,” and (3) the “restrained method.” In addition, Honeywell argued that a fourth method of sample preparation, i.e., the “ball method,” existed at the time of the invention, but it was not published. The ALJ had found that only when using the ball method did the results in MPE of the accused PET-yarn products fall within the claimed ranges of the ’976 patent. Therefore, the ITC had concluded that the choice of sample-preparation method was critical to determining whether a particular product is made by a process that infringes the ’976 patent.

The Federal Circuit agreed, but neither the claims, the written description, nor the prosecution history of the ‘976 patent discloses which of the four sample-preparation methods was used.

The Federal Circuit rejected Honeywell’s argument that the claim should be construed to read on the “ball method only.” Honeywell’s proffered construction is supported only by its own expert’s declaration and its own confidential document.

The Court also rejected a construction whereby the claims would be satisfied if the MPE falls within the claimed range using any one of the four known sample-preparation methods, concluding that such a construction would not give the public fair notice of the boundaries of the invention.

Finally, the Federal Circuit rejected a construction whereby the claims would be satisfied only if the MPE falls within the claimed range using each of the four known samplepreparation methods, because Honeywell admitted that such a construction would render the invention inoperable.

Having found the claims invalid for being indefinite, the Court vacated the noninfringement decision as moot.