Redefining Boundaries: How Cohesive Technologies Altered Literal and Equivalent Infringement

I. INTRODUCTION "The difficulty of literature is not to write, but to write what you mean."1 The human story is replete with instances where, due to its inherent limitations, language has failed to perfecdy communicate an abstract idea.2 Patent drafting, with its objective to reduce an abstract and complex inventive concept to text while at the same time providing an adequate level of public notice of what is protected, is not immune from these limitations.3 In light of the impossibility of written text achieving perfect protection and perfect notice to the public of what is protected by the patent, the most one can hope for is reasonable protection and reasonable notice. The patent drafter must strike a delicate balance between protection of the inventor's concept and sufficient public notice of what is protected. A simple example illustrates the problem. A hypothetical patent describes and claims the joining of two metal plates with a bolt. A competitor sells two metal plates joined with a rivet. In an infringement action, two different philosophies produce two different interpretations of the scope of the patent. Under a protectionist philosophy, the riveted plates infringe the patent because using a rivet in lieu of a bolt is a trivial and insignificant change to the substantive patented concept of joining two metal plates. This interpretation, while affording greater protection to the inventor, sacrifices clear public notice of what the patent covers by extending the scope of the patent beyond its literal terms. The disclosure in the patent was arguably not clear because it did not indicate to the public what constituted infringement. Under a disclosure philosophy, however, the riveted plates do not infringe the patent because they do not use a bolt, as is expressly disclosed and claimed in the patent. While under this philosophy the scope of the patent is clearly set forth to the public, it may not completely protect the inventive concept of the patent of joining two plates of metal.4 A significant body of case law has developed to strike a balance between these two adverse philosophies.5 The doctrine of equivalents and its limitations try to strike this balance by permitting an "equivalent" device to infringe under certain circumstances when literal terms of the patent are not met.6 Ideally, when a battle between disclosure and protection necessitates such a balance, the interpretation of what is a reasonable disclosure and what is reasonable protection is left to those most qualified in the field.7 The Court of Appeals for the Federal Circuit in Cohesive Technologies, Inc. v. Waters Corp. significantly altered that case lawestablished balance when it relied on its own interpretation of the phrase "about 30 pm," rather than leaving that interpretation to a qualified expert.8 In so doing, the court not only altered the wellestablished equivalent infringement analysis, but unnecessarily obscured the boundary between the analyses of equivalent infringement and literal infringement. As a result of this process, a patent loses its ability to fulfill its purpose to "promote the Progress of Science and useful Arts."9 This Note engages in an analysis of the effects of the Cohesive decision on the existing area of patent practice. Part II of this Note briefly describes the purpose and history of equivalent infringement and its relation to literal infringement. Part III discusses the Federal Circuit's treatment of Cohesive, highlighting how the court oversimplified the necessary analysis, disregarded its own legal ideology, and upset the historical balance between disclosure and protection. Part IV discusses the implications of the Cohesive decision on the future of patent law. Part V hypothesizes how Cohesive should have been decided by introducing a proposed simplified method. Part VI then summarizes this Note. II. STATE OF THE LAW A. Development of the Doctrine of Equivalents The constitutional purpose of a patent is "[t]o promote the Progress of Science and useful Arts. …