Deciphering Means-Plus-Function Claim Limitation Infringement under § 112, Paragraph 6: Finding Certainty in the Uncertain Case Law

The development of a technology-centered economy has increased the importance of patent rights. In order for these patent rights to have value, patentees must be able to ascertain the metes and bounds of their patent claims. In recent years the Federal Circuit has muddled means-plus-function claim limitation infringement analysis governed by 35 U.S.C. § 112, 6. Because the Federal Circuit uses different approaches to decide claims, it has become impossible to know the metes and bounds means-plus-function (MPF) limitations create.
For example, in two recent cases, Kemco Sales, Inc. v. Control Papers Co., Inc. and IMS Technology, Inc. v. Haas Automation, Inc., the Federal Circuit has used divergent approaches to analyze MPF claim limitation infringement. In Kemco, the court used the narrow approach to § 112, 6 infringement analysis, focusing on the structural equivalence of the accused structure to the patented structure. In IMS, the court used the contextual approach to infringement, looking at the claim limitation’s position in the context of the overall invention. This inconsistency unjustly forces inventors to rely on litigation to decide the scope of their patents’ rights to exclude.
In order to promote innovation, the more logical interpretation of 35 U.S.C. § 112, 6 is a narrow approach focusing on a simple structural equivalence comparison. This Comment shows the benefits of the narrow approach over the more complicated contextual approach.