Patent Claim Scope

Profession:Hale and Dorr LLP

Originally published on July 10, 2002

By Mr Anthony H. Kahng and Mr Donald R. Steinberg

In a patent, what is the scope of a claimed term? This question is especially vexing when only one embodiment of a claimed term is described in a patent. In particular, to what extent does such a claimed term cover embodiments not disclosed in the patent? During prosecution, patent examiners are instructed to give claim terms their "broadest reasonable interpretation." Similarly, the general rule in the courts has been that if a claim recites a structure without limiting it to a specific subset of structures, the claimed term will cover all types of that structure, regardless of whether those types are described in the patent.

Recently, in CCS Fitness, Inc. v. Brunswick Corp., the Court of Appeals for the Federal Circuit reaffirmed this general rule and described four situations in which a claim term may be constricted. These situations were not meant to be exhaustive but they reflect what the courts have done in other cases.

The claimed term at issue in CCS was a "reciprocating member" for an elliptical trainer. The term "member" was described in the patent with only one embodiment having a single straight bar. The accused exercise equipment had a corresponding reciprocating assembly with multiple curved structures. The court held that the claimed term "reciprocating member" covered the accused equipment with multiple components, although no such embodiment was described in the patent.

The court further explained that a court could constrict the ordinary meaning of a claim term in "at least" four ways.

When "the patentee acted as his own lexicographer and clearly set forth a definition of the disputed claim term in either the specification or prosecution history." This exception can be avoided unless the patent "clearly assigns" a unique definition to the claimed term. It follows that a patent drafter should be careful in defining any claimed terms in the specification or arguments to the Patent Office.

When the intrinsic evidence (that is, the specification and prosecution history) 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." Thus, a patent drafter should be careful in describing particular embodiments as important to distinguish the prior art or as important to the operation of the...

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