Curbing the Federal Circuit's enthusiasm: an argument for a rebuttable presumption against application of the doctrine of equivalents to disclosed but unclaimed subject matter.

• Author: Connor, Jeffrey M.
• Position: Case Note

INTRODUCTION

The laws that make up the patent corpus attempt to balance competing policy objectives of providing people an incentive to create new and useful products with the need to give society the benefits derived from a competitive marketplace. To strike this balance, Congress created a series of formalistic rules that the inventor must comply with to receive a patent. Recognizing, however, in the context of patent infringement that literal compliance with formalistic rules might turn a patent into a worthless object, courts turn to the doctrine of equivalents. The purpose of the doctrine of equivalents is to prevent someone from making insubstantial variations to a patented invention in order to avoid literal infringement.

Application of the doctrine of equivalents creates ambiguities as to the exact scope of a patent. The tension between the doctrine of equivalents and other patent doctrines such as the doctrine that disclosed but unclaimed subject matter is dedicated to the public, and the doctrine of prosecution history estoppel as applied to elements of claims that have been amended during prosecution, is a frequent topic of court opinions. Of late, the Court of Appeals for the Federal Circuit (Federal Circuit) has restricted the application of the doctrine of equivalents. In Johnson & Johnston Associates v. R.E. Service Co. the en banc Federal Circuit held that the doctrine of equivalents could not be applied to find infringement as to disclosed but unclaimed subject matter. (1) All such subject matter is deemed dedicated to the public. (2)

Part I of this Note introduces the rule of dedication to the public and the doctrine of equivalents. Additionally, Part I provides a brief discussion of the Supreme Court's doctrine of equivalents jurisprudence. Part II examines two ends of a spectrum of Federal Circuit jurisprudence regarding disclosed but unclaimed subject matter. Part III discusses the en banc Federal Circuit's decision in Johnson & Johnston. Part IV introduces the doctrine of prosecution history estoppel--a patent law doctrine that has posed problems analogous to those posed by disclosed but unclaimed subject matter. This Part will also discuss the divergent approaches taken by the Federal Circuit and the Supreme Court in dealing with the tension between the doctrine of equivalents and the doctrine of prosecution history estoppel as evidenced in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. (3) Finally, Part V advocates a Festo-like rebuttable presumption against application of the doctrine of equivalents to disclosed but unclaimed subject matter.

1. DEDICATION TO THE PUBLIC AND THE DOCTRINE OF EQUIVALENTS

   1. Dedication to the Public

      Under 35 U.S.C. [section] 112, a patent "specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention." (4) A literal reading of this provision seems to require that all information disclosed in the specification, but absent in the claims, is beyond the scope of the patent. Indeed, courts have interpreted the provision in this manner, and have created what is now the "well-established rule that 'subject matter disclosed but not claimed in a patent application is dedicated to the public.'" (5)

      On the surface, this rule makes sense. After all, the patentee is in the best position to know what the invention is and, consequently, the patentee should be responsible for claiming the full scope of the invention. Failure to include some subject matter logically could be interpreted to mean that the inventor does not regard this subject matter as part of the invention. (6) Courts thus have frequently used this rule to prevent an accused infringer from being found liable for literal infringement for practicing disclosed but unclaimed subject matter. (7)

      While strict application of the bright-line, per se rule that disclosed but unclaimed subject matter is dedicated to the public fulfills the policy objectives of patent law during patent prosecution, (8) the rule does not function quite so well in situations where a later judicial action deems subject matter outside the scope of the patent. For instance, in situations where patent claims are judicially invalidated as too broad, it is not fair, as an equitable matter, to assume that all the subject matter of those claims has been dedicated to the public. If the invalidated claims contain patentable and unpatentable material, the patentee should not be deemed to have dedicated the patentable material to the public simply because the examiner failed to reject a claim in light of the unpatentable material. In this and other situations where strict application of the dedication to the public rule would render an inequitable result, patentees have looked to the doctrine of equivalents as a mechanism with which a court could ground a finding of nonliteral infringement.

   2. The Doctrine of Equivalents

      1. An Introduction

         A defendant may infringe a patent either literally or via the doctrine of equivalents. "Literal infringement occurs when every element of the claim, as construed by the court, is found exactly in the accused device." (9) When an accused device does not literally infringe a patent, the courts may find the accused infringer to have infringed a patent under the doctrine of equivalents.

         The doctrine of equivalents is a judicially created equitable doctrine meant to ensure that a patent actually provides the patent holder a valuable property right. This doctrine provides that "a product or process that does not literally infringe upon the express terms of a patent claim may nonetheless be found to infringe if there is 'equivalence' between the elements of the accused product or process and the claimed elements of the patented invention." (10) This doctrine provides the patent holder with a scope of protection extending beyond the literal terms of the patent claim. Despite the notion that "the claims ... provide the measure of the patentee's right to exclude," (11) there are sound policy justifications for the doctrine of equivalents. As Justice Harlan noted in Graver Tank & Manufacturing Co. v. Linde Air Products Co.:

         [T]o permit imitation of a patented invention which does not copy every literal detail would be to convert the protection of the patent grant into a hollow and useless thing. Such a limitation would leave room for--indeed encourage--the unscrupulous copyist to make unimportant and insubstantial changes and substitutions in the patent which, though adding nothing, would be enough to take the copied matter outside the claim, and hence outside the reach of law. (12) This rationale is the foundation upon which the Supreme Court has predicated subsequent decisions reaffirming the doctrine of equivalents.

      2. A Brief History of the Supreme Court's Doctrine of Equivalents Jurisprudence

         1. Winans v. Denmead

            The case of Winans v. Denmead (13) provided the Supreme Court the forum, for the first time, to endorse the doctrine of equivalents. Winans involved a patent for the improvement of railroad cars carrying coal. (14) Under the terms of the patent, the railroad car would have a cylindrical upper-part and a conical lower-part. (15) The patentee's redesign allowed for a substantial increase in the load the railroad cars were capable of carrying. (16) The defendants made cars that were octagonal rather than circular, and the evidence showed that despite the different shape, defendants' cars were practically the same as patentee's. (17) Justice Curtis, writing for a majority of five justices, stated that "when a patentee describes a machine," he claims "not only the precise forms he has described, but all other forms which embody his invention." (18) When someone copies "the principle or mode of operation described, [it] is an infringement, although such copy should be totally unlike the original in form or proportions." (19) The Court remanded the case, holding that the lower court erred in not allowing the jury to determine whether the defendants copied the patentee's railroad cars. (20)

            The dissent in Winans was critical of the majority's reasoning. Justice Campbell thought the majority's decision was untethered to the demands of Congress. (21) Campbell noted that the patentee must "describe his invention, in such full, clear, and exact terms, that from the description, the invention may be constructed and used." (22) Only "preciseness[] and particularity, in the description of the invention, its principle, and of the matter claimed to be invented, will ... fulfil the demands of Congress or the wants of the country." (23) The majority's opinion left Justice Campbell wondering whether the Court could determine the exact scope of the patentee's patent. (24) Believing that the Court blurred the notice function the patent traditionally served, Justice Campbell thought the defendants presented the more compelling argument because nothing in the specification or the claims of the patent disclosed the cars that were made by the defendants. (25)

            Following the passage of the Patent Act of 1870, the Supreme Court "placed more emphasis on the patent claim language as the boundary of the patent monopoly." (26) Yet, this new emphasis on the language of the claims did not vitiate the role of the doctrine. (27) For approximately the next one hundred years, the doctrine of equivalents "survived as a tool of interpretation," (28) and the Supreme Court in 1950 reaffirmed it as a viable doctrine in the Graver Tank decision. (29)

         2. Graver Tank

            Graver Tank was a patent infringement action relating to an electric-welding process and the fluxes used in that process. (30) According to the patent before the Court, the patentee claimed fluxes containing calcium and magnesium silicates, both of which were silicates of an alkaline earth metal. (31) The alleged infringer used a similar flux but substituted calcium and...