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Superior Graphite Co. v. Timcal SA

May 8, 2006


The opinion of the court was delivered by: Judge Joan B. Gottschall


Plaintiff Superior Graphite Co. ("Superior") has brought suit against defendants Timcal SA, Timcal America Inc. and Timcal Canada Inc. (collectively "Timcal"), alleging infringement of its Patent No. 6,287,694 ("the '694 patent"). The parties have asked the court to construe the term "bulk volume" as it is used in the claims of the '694 patent. Timcal argues that "bulk volume" is not amenable to construction and renders the claims of the '694 patent indefinite. Superior argues that "bulk volume" as it is used in the patent is well understood by those of skill in the relevant art. This court finds that the term "bulk volume" is not indefinite and construes the term as discussed below.

I. Background

Superior's '694 patent describes a method for producing exfoliated graphite particles possessing low thermal and electrical resistivity, suitable for use in alkaline dry cell batteries. Briefly, the '694 patent describes a method by which purified mineral flake or synthetic graphite is intercalated with a graphite intercalation compound ("GIC"), typically a strongly oxidizing acid, that inserts between the lamellae, or layers, of the graphite structure. Upon rapid heating, the acid GIC expands, forcing the lamellae of the graphite to separate, expanding the graphite into an accordion-like configuration. The expanded graphite is subsequently air-milled, which further delaminates and separates it, yielding a fine graphite particulate with a greater surface area than graphite particles milled to the same particulate size but not intercalated and expanded. When employed in the active material in the positive electrode of an alkaline dry cell battery, the increased surface area to mass ratio of the delaminated graphite particles produced in this manner results in greater conductivity of the electrode, resulting in better performance and extended useful battery life. Superior filed the application for the '694 patent on March 13, 1998.

After preliminary claim construction briefing, the parties agree that the only term necessary for the court to construe is "bulk volume." As an example, claim 14 of the '694 patent states:

14. A method for making expanded graphite from lamellar graphite comprising:

a) providing lamellar graphite particles having at least a minimal purity;

b) intercalating the lamellar graphite particles with an expandable graphite intercalation method;

c) expanding the graphite intercalation compound to exfoliate the graphite particles; and

d) air milling the exfoliated graphite particles to further delaminate them to create an exfoliated graphite product having a surface area to mass ratio of at least 18 m2 /g and a bulk volume of at least 20 ml/g.

II. Analysis

Claim construction is a question of law for the court to decide. Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996). The Federal Circuit sitting en banc recently clarified the appropriate methodology for a court to use when performing claim construction. Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). The words of the claims in a patent are to be given the ordinary and customary meaning that would have been attributed to them by a person of ordinary skill in the art at the time the invention was made. Id. at 1312-13. The person of ordinary skill in the art is deemed to have read the term in the context of entire patent, including the claims themselves, the specification, and the prosecution history. Id. at 1313. The claims, specification, and prosecution history are so-called intrinsic evidence.

Extrinsic evidence is everything "external to the patent and prosecution history, including expert and inventor testimony, dictionaries, and learned treatises." Id. at 1317. Review of technical dictionaries and treatises can be helpful to the court in understanding the technology of the invention and can assist the court in determining the meaning of terms to those of skill in the art of the invention. Id. at 1318. Where extrinsic evidence conflicts with the intrinsic evidence of the patent, however, the intrinsic evidence controls. Id.

Like claim construction, claim indefiniteness is a question of law. Marley Mouldings Ltd. v. Mikron Industries, Inc., 417 F.3d 1356, 1359 (Fed. Cir. 2005). "A determination of claim indefiniteness is a legal conclusion that is drawn from the court's performance of its duty as the construer of patent claims." Datamize, LLC v. Plumtree Software, Inc., 417 F.3d 1342, 1347 (Fed. Cir. 2005)(quoting Personalized Media Communications., L.L.C. v. Int'l Trade Comm'n, 161 F.3d 696, 705 (Fed. Cir. 1998)).

The requirement that claim language be sufficiently definite arises from 35 U.S.C. § 112 ¶ 2 which states: "The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention." If a person of ordinary skill in the art can reasonably understand the claim when read in light of the specification, the claim is not indefinite. Marley Mouldings, 417 F.3d at 1359 ("The statute is satisfied if a person skilled in the field of the invention would reasonably understand the claim when read in the context of the specification."). "When a claim 'is not insolubly ambiguous, it is not invalid for indefiniteness.'" Id. at 1361 (quoting Bancorp Servs., L.L.C. v. Hartford Life Ins. Co., 359 F.3d 1367, 1372 (Fed. Cir. 2004)). The Federal Circuit has recently emphasized that the court must keep in mind the presumption of validity when determining whether a claim in invalid for indefiniteness:

In this regard it is important to note that an issued patent is entitled to a statutory presumption of validity. See 35 U.S.C. § 282 (2000). "By finding claims indefinite only if reasonable efforts at claim construction prove futile, we accord respect to the statutory presumption of validity and we protect the inventive contribution of patentees, even when the drafting of their patents has been less than ideal." Exxon Research & Eng'g v. U.S., 265 F.3d 1371, 1375 (Fed. Cir. 2001) (citation omitted). In this way we also follow the requirement ...

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