Festo: A Case
Contravening the Convergence of Doctrine of Equivalents Jurisprudence in
and the United States
Katherine E. White*
Cite as: Katherine E. White, FESTO: A Case Contravening the
Convergence of Doctrine of Equivalents Jurisprudence in Germany,
The United Kingdom, and the United States,
8 Mich. Telecomm.
Tech. L. Rev. 1 (2002),
available at
http://www.mttlr.org/voleight/white.pdf
Introduction
Part I
A. History
of Doctrine of Equivalents
B. History of Prosecution History Estoppel
Part II
A. Festo
Corp.v. Shoketsu Kinzoku Kogyo Kabushiki Co.
Part III
A. How Festo
Conflicts with Supreme Court Precedent
Part IV
A. Additional
Factors for Evaluating Equivalents:
The Formstein Test
Part V
A. Cases
Utilizing Additional Factors in Their Rationale.
1. Formstein
B. Merrell Dow Pharmaceuticals Inc. and Another v.
H.N. Norton & Co. Ltd. and Others
C. Wilson Sporting Goods Co.v. David Geoffrey
& Associates
D. Improving
the Hypothetical Claim Analysis of Wilson Sporting Goods
Part VI
A. Tangential
Issues Related to Festo
B. Maxwell v. Baker, Inc.
C. YBM Magnex,
Inc.v. International Trade Commission
Part VII
Conclusion
Despite differences in patent law jurisprudence in Germany, the United Kingdom and the United States, the fundamental principles underlying each system serve the same basic purpose: to encourage technological innovation and dissemination of knowledge.[1] In granting exclusive patent rights, it is important that the scope of patent protection not be so broad as to remove existing knowledge from the public domain.[2] The scope of protection should strike a balance between granting adequate patent rights while preserving the public’s ownership in the public domain or the prior art. To encourage innovation patentees must attain significant exclusive rights, while potential infringers receive sufficient notice of a patent’s scope.[3] To realize patent system goals, the scale measuring adequate patent protection should not be so heavy as to outweigh the public’s right to know the scope of a patentee’s rights.[4]
Several issues in patent law jurisprudence in the
aforementioned countries reveal the tension between adequate protection and the
rights of the public. Such doctrines include: a) the on-sale bar,[5]
b) public use,[6]
c) obviousness,[7]
and d) the doctrine of equivalents.[8]
While all four issues are illustrative, this Article focuses on the doctrine of
equivalents.
Infringement occurs under the doctrine of equivalents when
an accused device does not fall literally within the scope of the claim
language, yet is an equivalent of what is claimed.[9]
The doctrine of equivalents prevents those who make insubstantial changes to a
patented invention from reaping the benefits of such an insignificant contribution.[10]
As such, the doctrine elevates substance over form in circumscribing
infringement. In three major industrialized nations—
In Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.,[15] the United States Court of Appeals for the Federal Circuit (Federal Circuit) unraveled centuries of precedent. The court virtually eliminated the doctrine of equivalents as a method of finding patent infringement in routine and conventional situations. Prior to Festo, the doctrine of equivalents was a viable theory for determining patent infringement. After Festo, the policies underlying the doctrine of equivalents have taken a back seat to bright line rules with little substantive basis.
The Festo court held that any narrowing amendment made to a claim element during prosecution, for “a reason related to patentability,” triggers prosecution history estoppel such that no range of equivalents is available for that amended claim element.[16] According to the court, what was said or even whether the applicant was silent as to why the narrowing amendment was made during prosecution is irrelevant.[17] No range of equivalents is given to the amended claim element absolutely.[18] Proclaiming the doctrine of equivalents unworkable in its current state, the court instituted this drastic change.[19] This produced the even more troubling result that amendments made for procedural reasons, rather than for distinguishing prior art, preclude any range of equivalents as to the amended claim element. “[B]ecause most patents contain claims that were amended during prosecution, . . . [Festo] effectively strips most patentees of their rights to assert infringement under the doctrine of equivalents . . . .”[20]
Prior to Festo,
the Federal Circuit used a “flexible bar” approach to determine equivalents.
There was no entrenched formula for establishing the range of equivalents
available to a claim element.[21]
Equivalency decisions were made on a case-by-case basis, with many variables
evaluated in reaching a decision.[22]
The
In Festo, the Federal Circuit created a bright line rule to solve a problem it considers “unworkable.” Bright line rules do, in most instances, provide clear guidance. Moreover, society needs bright line rules in numerous important situations. In criminal cases, for example, where basic human rights are at stake, bright line rules serve both as a bulwark of individual liberty and as a means of ensuring that, otherwise well founded, convictions are not overturned. Bright line rules defining when police officers must obtain a search warrant or “read” people their rights meet this goal.[23] The Festo “complete bar” rule, however, serves no such fundamental purpose.
Rather than permit form to triumph over substance, perhaps
it is better to substantively examine the major public policy issues
surrounding the application of the doctrine of equivalents. These issues can be
addressed in the context of a doctrine of equivalents analysis, without
virtually eliminating the doctrine altogether, in order to embrace formal
strictures.
The doctrine of equivalents has retained its vitality in
other jurisdictions, namely
Prosecution history estoppel, to complement and not subsume the doctrine of equivalents, should be used only as an “estoppel” doctrine. “Estoppel prevents a litigant from denying an earlier admission upon which another has already relied.”[26] When a patentee affirmatively, not silently, surrenders patent scope, the patentee should be constrained to that abandonment. This comports with the underlying principle protecting the public’s right to that which is in the public domain, as well as the notice requirement.
To further ensure that the scope of equivalents does not incorporate the prior art, a doctrine of equivalents analysis should formally include the following factors:
If an allegedly infringing device or process forms part of the prior art, there can be no infringement; and
If an allegedly infringing device or process would have been obvious over the prior art, there can be no infringement; and
The aforementioned tests may only encompass those elements of the allegedly infringing device that are covered in the patent claim or are an equivalent to an element of the patent claim.[27]
Analyzing these factors in conjunction with a doctrine of
equivalents formulation will create or encourage a substantive inquiry, making
it unnecessary to throw out the rule, the doctrine of equivalents, in favor of
the exception, prosecution history estoppel. Moreover, these three factors
maintain consistency with the underlying principles behind the doctrine of
equivalents in
Part I of this article is a general overview of the history of both the doctrine of equivalents and prosecution history estoppel; Part II discusses Festo and what the case holds; Part III discusses where Festo conflicts with Supreme Court precedent; Part IV articulates the additional factors that encompass public policy concerns regarding scope restraint as the basis for evaluating equivalents; Part V presents and analyzes cases utilizing the Formstein test in their rationales; Part VI explores tangential issues prompted by the Festo decision; and Part VII sets forth the conclusions reached from the analysis.
To comprehend the extent to which Festo has changed the law, a review of the history and significance of the doctrine of equivalents is instructive. This is important because Festo is a virtual elimination of this kind of patent infringement.
The United States Constitution grants Congress the power
“[t]o promote the progress of Science and useful Arts, by securing for limited
Times to Authors and Inventors the exclusive Right to their respective Writings
and Discoveries.”[28]
In implementing this power, Congress has granted patentees rights and remedies
for patent infringement to deter and compensate for any trespass to their
inventions.[29]
Beyond providing a list of infringing acts, the patent statutes do not further
define how
patent infringement is to be determined.[30]
Defining what constitutes patent infringement has been left to the courts.
Courts have recognized two types of infringement, literal and doctrine of
equivalents.[31]
Literal infringement exists when, after the claims have been construed, the “accused matter falls clearly within the claim,”[32] meaning that the accused device falls within the literal language of the claim. The doctrine of equivalents provides that a patentee’s invention covers not only the literal language of the claim, but also all other forms that embody his or her invention.[33]
As early as 1853, the Supreme Court expressed that a patent covers “not only the precise forms [the patentee] has described, but all other forms which embody his [or her] invention . . . .”[34] Pronouncing a preference for substance over form, the Court said:
Where form and substance are inseparable, it is enough to look at the form only. Where they are separable; where the whole substance of the invention may be copied in a different form, it is the duty of courts and juries to look through the form for the substance of the invention—for that which entitled the inventor to his [or her] patent, and which the patent was designed to secure; where that is found, there is an infringement . . . .[35]
The Court further highlighted that a patent is an exclusive right that “is not secured, if the public are at liberty to make substantial copies of it, varying its form or proportions.”[36]
Almost a century later, in Graver Tank & Manufacturing Co. v. Linde Air Products.
[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 the law. One who seeks to pirate an invention, like one who seeks to pirate a copyrighted book or play, may be expected to introduce minor variations to conceal and shelter the piracy. Outright and forthright duplication is a dull and very rare type of infringement. To prohibit no other would place the inventor at the mercy of verbalism and would be subordinating substance to form. It would deprive him of the benefit of his invention and would foster concealment rather than disclosure of inventions, which is one of the primary purposes of the patent system.[38]
The fundamentally self-evident nature of the Court’s words notwithstanding, defining when non-literal piracy of a patented invention occurs has proven difficult. The Court’s standard required the development of doctrines that were, by their very nature, meant to be applied on a case-by-case basis.
The doctrine of equivalents is the principal doctrine that
defines non-literal infringement and prevents an accused infringer from
escaping liability for patent infringement through making only minor or insubstantial
changes, while retaining the invention’s central and fundamental likeness or
identity.[39]
A patentee may invoke the doctrine of equivalents to proceed against an alleged
infringer if his or her device “ ‘performs substantially the same function
in substantially the same way to obtain the same result.’ ”[40]
The doctrine protects inventors not only from “unscrupulous copyists”[41],
but also from “unanticipated equivalents” found in technology after the patent
has issued.[42]
Patent claims define the scope or the “metes and bounds” of the patented invention.[43] On the one hand, it is important to give the patentee a range of equivalents to protect his or her invention. On the other hand, expanding the scope of equivalents too far could thwart the requirement that the patent claims give “fair notice” of a patent’s scope.[44] The Supreme Court recently revisited this issue in Warner-Jenkinson Co. v. Hilton-Davis Chemical Co.[45]
In Warner-Jenkinson, the Court announced that the “doctrine of equivalents, when applied broadly, conflicts with the definitional and public-notice functions of the statutory claiming requirement.”[46] The Court provided means to constrain the doctrine by adopting the “all elements rule.”[47] The Court stressed that,
Each element contained in a patent claim is deemed material to defining the scope of the patented invention, and thus the doctrine of equivalents must be applied to individual elements of the claim, not to the invention as a whole. It is important to ensure that the application of the doctrine, even as to an individual element, is not allowed such broad play as to effectively eliminate that element in its entirety.[48]
Since Warner-Jenkinson, courts compare the patent claims to the allegedly infringing device in order to determine patent infringement under the doctrine of equivalents. If the device does not fall literally within the claims, then courts reexamine the allegedly infringing device to determine whether doctrine of equivalents infringement occurred. This can happen if for every claim element, there is an equivalent element in the infringing device.[49] The idea is to balance the patentee’s right to protect the entire scope of the claimed invention against the public notice requirement that the claims define the metes and bounds of the patented invention.[50] For an element to be an equivalent, the differences between the claim element and the equivalent must be, according to one skilled in the art, insubstantial or interchangeable.[51] For example, a difference may be insubstantial or interchangeable if the accused elements perform substantially the same function in substantially the same way to obtain substantially the same result as the invention.[52] The particular linguistic framework for determining equivalents is not set in stone. “Different linguistic frameworks may be more suitable to different cases, depending on their particular facts.”[53] The Court deferred to the Federal Circuit to prescribe other appropriate methods of determining equivalents.[54]
Another way to prevent
the doctrine of equivalents from expanding too far and, thus, thwarting the
notice requirement is to use the doctrine of prosecution history estoppel.[55]
Prosecution history estoppel limits a patentee from expanding patent scope when
such coverage has been relinquished during prosecution of the patent
application before the Patent and Trademark Office (“PTO”).[56]
The Warner-Jenkinson Court further narrowed
the doctrine of equivalents by creating a new presumption affecting prosecution
history estoppel:
Where no explanation
[of a patent amendment] is established, . . . the court should
presume that the patent applicant had a substantial reason related to
patentability for including the limiting element added by amendment.[57]
The Court emphasized,
however, that this presumption is rebuttable if the reason for an amendment
gives “proper deference to the role of claims in defining an invention and
providing public notice, and to the primacy of the PTO in ensuring that the
claims allowed cover only subject matter that is properly patentable in a
proffered patent application.”[58]
Another recent change
to the Court’s precedent concerns applying prosecution history estoppel to
amendments made for reasons other than distinguishing over the prior art. The
The Court left a
question unanswered in Warner-Jenkinson,
however: what range of equivalents is available when an estoppel applies under
the doctrine of prosecution history estoppel? In Festo, the Federal Circuit answered this question: no range of
equivalents is available.
It is helpful to visit
the precedents surrounding the doctrine of prosecution history estoppel in
order to understand the impact of Festo
on patent law jurisprudence.
As an estoppel doctrine, prosecution history estoppel prevents
a litigant from denying an earlier admission when another has relied upon it.[60]
In the context of patent prosecution, “the admission is the applicant’s
surrender of claim scope to acquire a patent.”[61]
“Prosecution history estoppel applies both ‘to claim amendments to overcome
rejections . . . and to arguments submitted to obtain the
patent.’ ”[62]
Thus, the scope of the surrender, normally, must be determined before the
estoppel applies. Before Festo, in order to determine equivalents scope, courts
looked to actual amendments and attorney arguments to evaluate what subject
matter was surrendered. This can be characterized as a bargain (or contract)
struck between the patent attorney and the examiner in order to acquire the
patent.[63]
“A patentee is not free to retrade or renege on a deal struck with the PTO
during patent prosecution.”[64]
The Supreme Court historically treated prosecution history estoppel as an estoppel doctrine. The Court inquired into what the patentee surrendered in order to attain a patent on the invention. As early as 1886, the Court in Shepard v. Carrigan[65] opined that where a patentee gives up claim scope in order to get a patent issued, “he cannot after the issue of the patent broaden his claim by dropping the element which he was compelled to include in order to secure his patent.”[66] The same year, the Court held in Sutter v. Robinson[67] that during the prosecution process, where the patentee limited his claims, “[h]e is not at liberty now to insist upon a construction . . . he was expressly required to abandon and disavow as a condition of the [patent] grant.”[68]
In 1900, the Court in Hubbell v. United States[69] examined the patentee’s file wrapper history. The Court discovered that in order to obtain a patent, patentee was compelled to accept a narrower claim construction than that written in the original application. The Court held that:
[I]t is well settled that the claim as allowed must be read and interpreted with reference to the rejected claim and to the prior state of the art, and cannot be so construed as to cover either what was rejected by the Patent Office or disclosed by prior devices.[70]
In 1921, the Court in Weber Electronic Co. v. E.H. Freeman Electronic Co.