Comment by William E. Eshelman
The Constitution of the United States empowers Congress to create a patent system. Under this authority, Congress created a system that grants patent owners the right, for seventeen years, “to exclude others from making, using, or selling the invention throughout the United States, and, if the invention is a process, of the right to exclude others from using or selling throughout the United States, or importing into the United States, products made by that process . . . .” The patent statute enacted by Congress requires that applications for patents include specifications that “conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.” Litigation typically occurs when a patent owner sues someone who has allegedly violated, or infringed, the patentee's exclusive rights to his invention. Though infringement may occur in several ways, this Comment is limited to the issue of whether the patented invention and the allegedly infringing device are the same thing. Courts examine these types of infringement allegations by comparing the patent claims to the device or process in question. Generally, if the patent claims literally “read on” the accused device, then the accused device constitutes literal infringement of the patent. Even if the accused device does not literally infringe a patent, the “doctrine of equivalents” provides that an accused device infringes if it performs substantially the same function, in substantially the same way, to obtain substantially the same result as the patented invention.
In 1950, the Supreme Court stated its latest formulation of the doctrine of equivalents in Graver Tank & Manufacturing Co. v. Linde Air Products Co. Although the Graver Tank case remains the leading authority on the doctrine of equivalents, the interpretations of Graver Tank by the Court of Appeals for the Federal Circuit (CAFC) in its 1987 decision, Pennwalt Corp. v. Durand-Wayland, Inc., have created a great deal of controversy. The Pennwalt case was decided en banc with six judges joining Judge Bissell's majority opinion, three judges joining Judge Bennett's dissent, one concurring judge filing “additional views” in support of the majority opinion, and one dissenting judge filing a “commentary” in support of the dissent. In addition to this disagreement among the judges, commentators have taken conflicting positions regarding the substance, importance, and impact of Pennwalt on the doctrine of equivalents. This Comment examines the effect of Pennwalt by analyzing post-Pennwalt CAFC decisions that address the doctrine of equivalents.
About the Author
William E. Eshelman.
Citation
65 Tul. L. Rev. 883 (1991)