Exclusion confusion? A defense of the Federal Circuit's specific exclusion jurisprudence.

• Author: Magic, Peter Curtis

Specific exclusion has become a controversial limitation on the doctrine of equivalents, which is itself an essential and controversial area of patent law. The doctrine of equivalents allows a patentee to successfully claim infringement against devices that are outside of the literal reach of the language used by the patentee in her patent to describe what she claims as her invention. The Supreme Court has prescribed some of the outer limits of the doctrine of equivalents and articulated the underlying policy concerns that inform its analysis--noting that courts should balance protection of the patentee's intellectual property with the public's reasonable expectations of the bounds of the patent--but has entrusted most of the doctrine's development to the Federal Circuit. Critics argue that the Federal Circuit has applied specific exclusion, which precludes the doctrine of equivalents from reaching subject matter that is "specifically excluded" by the language used in the patent to describe the invention, in a way that does not adhere to the Supreme Court's guidance on the doctrine of equivalents. The critics assert that the Federal Circuit has unduly narrowed the doctrine of equivalents by applying specific exclusion too aggressively. This Note demonstrates that the critics' extreme characterization of Federal Circuit specific exclusion case law is unwarranted. The Federal Circuit has consistently and conscientiously applied specific exclusion, and their decisions conform to the Supreme Court's' guidance on the public notice function of patent claims. At the same time, the Federal Circuit has protected patentees by not allowing specific exclusion to reduce the doctrine of equivalents to another test for literal infringement.

TABLE OF CONTENTS INTRODUCTION I. THE SUPREME COURT'S TREND OF NARROWING THE DOCTRINE OF EQUIVALENTS II. THE FEDERAL CIRCUIT'S APPROACH TO SPECIFIC EXCLUSION Is CONSISTENT WITH SUPREME COURT PRECEDENT ON THE DOCTRINE OF EQUIVALENTS A. The Federal Circuit Has Applied Specific Exclusion with an Eye Towards the Public Notice Function of Patent Claims B. The Federal Circuit Has Applied Specific Exclusion to Find Nonequivalence where the Accused Device is Substantially Different from the Language of a Claim Limitation C. The Federal Circuit Has Applied Specific Exclusion to Avoid Vitiating the Language of Claim Limitations D. The Federal Circuit Has Applied Specific Exclusion in Accordance with the Supreme Court's Guidance on Prosecution History Estoppel E. Specific Exclusion Has Not Made After-Arising Technologies Immune to Infringement Liability III. CONTRARY TO CRITICS' ARGUMENTS, THE FEDERAL CIRCUIT'S SPECIFIC EXCLUSION JURISPRUDENCE HAS NOT ENDANGERED THE DOCTRINE OF EQUIVALENTS A. The Federal Circuit's Specific Exclusion Jurisprudence Has Not Reduced the Doctrine of Equivalents to a Test for Literal Infringement B. The Federal Circuit Has Not Applied Specific Exclusion in a Manner that Ignores Other Tests for Equivalence CONCLUSION INTRODUCTION

The doctrine of equivalents in patent law "is premised on language's inability to capture the essence of innovation." (1) Because a patent's claims-the part of the patent that defines what the patentee claims as her invention--consist of sentences and phrases, they suffer from the imprecision inherent in language itself. The doctrine of equivalents states that the scope of a patent is not necessarily limited to the literal meaning of the words in the patent's claims, but may encompass inventions with elements insubstantially different from those described in the patent. The scope of the doctrine is limited by several analytical tools, including the all limitations rule, prosecution history estoppel, and the specific exclusion doctrine. (2) This Note focuses on the specific exclusion doctrine, which mandates that the doctrine of equivalents cannot bring into a patent's scope "a structure that is specifically excluded from the scope of the claims." (3) Specific exclusion has been applied somewhat liberally by the Federal Circuit, sparking criticism that it has narrowed the doctrine of equivalents too far. (4) Nevertheless, as this Note explains, the Federal Circuit has applied specific exclusion in a manner consistent with the Supreme Court's view of the doctrine of equivalents generally and has limited the doctrine of equivalents to a similar degree as other limitations. Furthermore, contrary to the views of critics, specific exclusion has not been applied by the Federal Circuit in a manner that vitiates (5) the doctrine of equivalents altogether.

The two competing interests shaping the doctrine of equivalents are the public-notice function of patent claims and protection of the patentee's property rights. On one hand, the Supreme Court has stressed the importance of clarity in patent claim language so that the patentee "know[s] what he owns, and the public ... know[s] what he does not." (6) On the other hand, the Court has recognized that "[i]f patents were always interpreted by their literal terms, their value would be greatly diminished [because] [u]nimportant and insubstantial substitutes ... could defeat the patent." (7) These competing concerns pull in opposite directions on the doctrine of equivalents. (8)

This Note contends that the Federal Circuit's specific exclusion jurisprudence balances public notice and protection of the patentee in accordance with Supreme Court precedent and has not improperly narrowed the doctrine of equivalents. Part I of this Note analyzes the Supreme Court's doctrine of equivalents jurisprudence, explaining that while the Court has not addressed the specific exclusion doctrine directly, the trend has been to narrow the doctrine of equivalents. Part II explores the role of specific exclusion as a necessary limit on the doctrine of equivalents and argues that the Federal Circuit has applied the specific exclusion limitation in a manner consistent with the Supreme Court's treatment of the doctrine of equivalents. Specifically, this Note examines how the Supreme Court has explained the proper role of other limitations on the doctrine of equivalents and argues that the Federal Circuit's specific exclusion jurisprudence fits within that framework. Part III refutes the criticism that the Federal Circuit has applied specific exclusion so strongly that it has effectively vitiated the doctrine of equivalents and shows not only that the Federal Circuit has conscientiously avoided narrowing the doctrine of equivalents out of existence, but that it has reconciled specific exclusion with several measures of equivalence.

1. THE SUPREME COURT'S TREND OF NARROWING THE DOCTRINE OF EQUIVALENTS

   This Part examines the creation of the doctrine of equivalents and the Supreme Court's progressive narrowing of the doctrine through the application of different analytical frameworks, such as the all limitations rule and the "insubstantial differences" test. This Part also examines the Court's narrowing of the doctrine of equivalents through progressively stronger application of prosecution history estoppel, a limitation on the doctrine stemming from an increased concern for the public notice function of patent claims. Although specific exclusion has never been addressed by the Court, the aforementioned frameworks serve as evidence that the Federal Circuit's specific exclusion jurisprudence fits comfortably within the Supreme Court's narrow conception of the doctrine of equivalents.

   The doctrine of equivalents originated in Winans v. Denmead (9) in 1853. The dispute in Winans centered on a patent for a new design of a rail car used to carry coal. The patent claimed a cylindrical rail car container that narrowed at its base to form the frustum of a cone, with the frustum ending at a closed bottom. (10) The infringing design was an octagonal container that became an inverted pyramid at its bottom. (11)

   The Court concluded that the evidence supported a finding that the defendant's eight-sided rail car was equivalent to the plaintiff's patented design. (12) The Court conceded that the plaintiff's patent explicitly claimed "one form only. (13) Nevertheless, the Court agreed with the plaintiff's argument that the patent should cover not only a container of perfectly circular design, but also designs of similar form that perform the same function, such as a 100-sided approximation to a circular design. (14)

   The Court held that when a patentee writes a patent claim, "he is understood to intend to claim, and does by law actually cover, not only the precise forms he has described, but all other forms which embody his invention." (15) The Winans Court explained that the doctrine of equivalents was an essential part of patent law (16) because "the property of inventors would be valueless, if it were enough for the defendant to say" that his form was not exactly the one that the plaintiff had claimed. (17) Indeed, the Court found it "difficult to perceive how any other rule could be applied ... to cases like this." (18)

   Nearly one hundred years after Winans, the Supreme Court reaffirmed the vitality of the doctrine of equivalents in Graver Tank & Manufacturing Co. v. Linde Air Products Co. and created a new test for applying the doctrine. (19) Graver Tank held that not to recognize any infringement beyond literal infringement "would be to convert the protection of the patent grant into a hollow and useless thing." (20) The Court further recognized that to do otherwise "would be subordinating substance to form" (21) and would permit one to "practice a fraud on a patent." (22) After endorsing the doctrine of equivalents as a necessary component of patent law, Graver Tank articulated the test for applying the doctrine commonly known as the "function-way-result" test. The Court held that a plaintiff could evoke the doctrine of equivalents if the defendant's device "performs substantially the same function in substantially the same way to...