Patent - Festo -
Doctrine of Equivalents & Prosecution History Estoppel
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©A. Hawkins 2002
Part 2
Festo v. Shoketsu (SMC)[1] 234 F.3d 558 (Fed. Cir. 2000) (en banc)
(November 29, 2000)[2] Reversed
Judges and Opinions
Before Mayer, Chief Judge, Newman, Michel,
Plager, Lourie, Clevenger, Rader, Schall, Bryson, Gajarsa, Linn, and Dyk,
Circuit Judges.
Opinion for the court filed by Circuit Judge
Schall, in which Chief Judge Mayer and Judges Plager, Lourie, Clevenger,
Bryson, Gajarsa, and Dyk join; in which
Judges Michel, Rader, and Linn join with respect to PARTS III-A, III-B, and
III-D; and in which Circuit Judge Michel
joins with respect to PART III-E.
Concurring opinion by Circuit Judge Plager
Concurring opinion by Circuit Judge Lourie
Opinion concurring-in-part and
dissenting-in-part with respect to PART III-C filed by Circuit Judge Michel, in
which Circuit Judge Rader joins.
Opinion
concurring-in-part and dissenting-in-part with respect to PART III-C filed by
Judge Rader, in which Judges Michel and Linn join.
Opinion
concurring-in-part and dissenting-in-part with respect to PART III-C filed by
Judge Linn, in which Judge Rader joins.
Opinion
concurring-in-part and dissenting-in-part with respect to PARTS III-A, III-B,
III-C, and IV filed by Judge Newman .
Opinion by Judge Schall
This is an appeal from the judgment of the
United States District Court for the District of Massachusetts that Shoketsu
Kinzoku Kogyo Kabushiki Co., Ltd. (also known as SMC Corporation) and SMC
Pneumatics, Inc. (collectively, "SMC") infringed U.S. Patent No.
4,354,125 (the "Stoll patent") and U.S. Patent No. B1 3,779,401 (the
"Carroll patent"), both owned by Festo Corporation
("Festo"), under the doctrine of equivalents. We took the case en
banc to resolve certain issues relating to the doctrine of equivalents that
remained in the wake of the Supreme Court's decision in Warner-Jenkinson Co. v.
Hilton Davis Chemical Co.[3] Specifically, we asked the parties to brief
the following five questions for rehearing en banc:
1. For the purposes of determining whether an
amendment to a claim creates prosecution history estoppel, is "a
substantial reason related to patentability,"[4] limited to those amendments made to overcome
prior art under § 102 and § 103, or does "patentability" mean any
reason affecting the issuance of a patent?
2. Under Warner-Jenkinson, should a
"voluntary" claim amendment--one not required by the examiner or made
in response to a rejection by an examiner for a stated reason--create
prosecution history estoppel?
3. If a claim amendment creates prosecution
history estoppel, under Warner-Jenkinson what range of equivalents, if any, is
available under the doctrine of equivalents for the claim element so amended?
4. When "no explanation [for a claim
amendment] is established," Warner-Jenkinson,[5] thus invoking the presumption of prosecution
history estoppel under Warner-Jenkinson, what range of equivalents, if any, is
available under the doctrine of equivalents for the claim element so amended?
5. Would a judgment of infringement in this case
violate Warner-Jenkinson's requirement that the application of the doctrine of
equivalents "is not allowed such broad play as to eliminate [an] element
in its entirety,"[6] In other words, would such a judgment of
infringement, post Warner-Jenkinson, violate the "all elements" rule?
We begin with a brief synopsis of our answers to
the en banc questions and a summary of how those answers affect the disposition
of this appeal. In response to En Banc Question 1, we hold that "a substantial reason related to
patentability" is not limited to overcoming prior art, but includes other
reasons related to the statutory requirements for a patent. Therefore, an
amendment that narrows the scope of a claim for any reason related to the statutory
requirements for a patent will give rise to prosecution history estoppel with
respect to the amended claim element.1[7] In response to En Banc Question 2, we hold that "voluntary" claim
amendments are treated the same as other claim amendments; therefore, any
voluntary amendment that narrows the scope of a claim for a reason related to
the statutory requirements for a patent will give rise to prosecution history
estoppel with respect to the amended claim element. In response to En Banc
Question 3, we hold that when a claim
amendment creates prosecution history estoppel, no range of equivalents is
available for the amended claim element. In response to En Banc Question 4, we hold that "unexplained"
amendments are not entitled to any range of equivalents. We do not reach En
Banc Question 5, for reasons which will become clear in our discussion of the
specific case before us.
In view of
our answers to the en banc questions, we reverse the judgment that claim 1 of
the Stoll patent and claims 5, 6, and 9 of the Carroll patent were infringed
under the doctrine of equivalents. The claim elements that were found to be
infringed by equivalents were added during prosecution of the Stoll patent and
during reexamination of the Carroll patent. The amendments that added those
elements narrowed the scope of the claims. Festo has not established
explanations unrelated to patentability for these amendments; accordingly, no
range of equivalents is available for the amended claim elements. Because the
parties agree that SMC does not produce a device that literally satisfies those
claim elements, the judgment of infringement must be reversed.
Section I of this opinion provides a brief
overview of the doctrine of equivalents and prosecution history estoppel.
Section II discusses the Supreme Court's decision in Warner-Jenkinson. Section
III sets forth our answers to the en banc questions. In Section IV, we decide
the appeal before us by applying our answers to the en banc questions to the
facts of the case.
DISCUSSION
I. The Doctrine of Equivalents and Prosecution
History Estoppel
The doctrine of equivalents prevents an accused
infringer from avoiding liability for infringement by changing only minor or
insubstantial details of a claimed invention while retaining the invention's
essential identity.[8] The doctrine of equivalents is utilized
"'[t]o temper unsparing logic and prevent an infringer from stealing the
benefit of the invention.'"[9] In pursuing these goals, the doctrine
attempts to strike a balance between ensuring that the patentee enjoys the full
benefit of his patent and ensuring that the claims give "fair notice"
of the patent's scope.[10] This balance can be easily upset, however,
because "the doctrine of equivalents, when applied broadly, conflicts with
the definitional and public-notice functions of the statutory claiming
requirement."[11]
Prosecution history estoppel is one tool that
prevents the doctrine of equivalents from vitiating the notice function of
claims.[12] Actions by the patentee, including claim
amendments and arguments made before the Patent Office, may give rise to
prosecution history estoppel.[13] "Prosecution history estoppel precludes
a patentee from obtaining under the doctrine of equivalents coverage of subject
matter that has been relinquished during the prosecution of its patent
application."[14] Therefore, "[t]he doctrine of
equivalents is subservient to . . . [prosecution history] estoppel."[15] The logic of prosecution history estoppel is
that the patentee, during prosecution, has created a record that fairly
notifies the public that the patentee has surrendered the right to claim
particular matter as within the reach of the patent.
II. Warner-Jenkinson
In this en banc rehearing, we focus our
attention on the effect of Warner-Jenkinson on our case law relating to the
doctrine of equivalents and prosecution history estoppel.[16]
The patent before the Court in Warner-Jenkinson
disclosed an improved process for purifying dyes which used a method called
"ultrafiltration."[17] During prosecution, the patentee amended the
claims to recite that the process is carried out "at a pH from
approximately 6.0 to 9.0."[18] The accused process was carried out at a pH
of 5.0.[19] In light of these facts, the Supreme Court
embarked on an "endeavor to clarify the proper scope of the doctrine"
of equivalents.[20]
The Court dismissed the arguments of
Warner-Jenkinson (the alleged infringer) that the doctrine of equivalents, as
established in Graver Tank, did not survive the 1952 revision of the Patent
Act.[21] The Court nevertheless noted its concern
that "the doctrine of equivalents, as it has come to be applied since
Graver Tank, has taken on a life of its own."[22] The Court agreed with Warner-Jenkinson
"that Graver Tank did not dispose of prosecution history estoppel as a
legal limitation on the doctrine of equivalents."[23] However, the Court rejected
Warner-Jenkinson's argument "that the reason for an amendment during
patent prosecution is irrelevant to any subsequent estoppel."[24] The Court noted that "[i]n each of our
cases cited by petitioner and by the dissent below, prosecution history
estoppel was tied to amendments made to avoid the prior art, or otherwise to
address a specific concern--such as obviousness--that arguably would have
rendered the claimed subject matter unpatentable."[25] The Court therefore saw "no substantial
cause for requiring a more rigid rule invoking an estoppel regardless of the
reasons for a change."[26]
Turning to the facts at hand, the Court noted
that, although the parties did not dispute that the upper pH limit of 9.0 was
added to avoid the prior art, "the reason for adding the lower limit of
6.0 is unclear."[27] Presented "with the problem . . . where
the record seems not to reveal the reason for including the lower pH limit of
6.0," the Court "place[d] the burden on the patent holder to
establish the reason for an amendment required during patent prosecution."[28] The Court stated that courts will have to
"decide whether the [proffered] reason is sufficient to overcome
prosecution history estoppel as a bar to application of the doctrine of
equivalents to the element added by that amendment."[29] The Court also stated that "[w]here no
explanation is established, . . . the court should presume that the patent
applicant had a substantial reason related to patentability for including the
limiting element added by the amendment."[30] Therefore, "prosecution history
estoppel would bar the application of the doctrine of equivalents as to that
element."[31] Because Hilton Davis had "not proffered
in . . . [the Supreme] Court a reason for the addition of the lower pH
limit," the Court remanded the case for this court to consider whether
Hilton Davis had offered reasons for the amendment that added the lower pH
limit and to determine whether Hilton Davis should be given the opportunity to
establish such reasons.[32]
The Court rejected the other restrictions on the
doctrine of equivalents proposed by Warner-Jenkinson.[33] Specifically, the Court refused to
"require judicial exploration of the equities of a case before allowing
application of the doctrine of equivalents,"[34] , refused to require
"proof of intent" on the part of the alleged infringer before the
doctrine of equivalents could be applied,[35] and refused to adopt "independent
experimentation" as "an equitable defense to the doctrine of
equivalents,"[36] The Court also refused to limit the doctrine
of equivalents "to equivalents that are disclosed within the patent
itself," reasoning that the "proper time for evaluating equivalency .
. . is at the time of infringement, not at the time the patent was
issued."[37]
In closing, the Court stated that it chose to
"adhere to the doctrine of equivalents," which "should be
applied as an objective inquiry on an element-by-element basis."[38] The Court noted that "[p]rosecution
history estoppel continues to be available as a defense to infringement."[39] However, "if the patent holder
demonstrates that an amendment required during prosecution had a purpose
unrelated to patentability, a court must consider that purpose in order to
decide whether an estoppel is precluded."[40] If "the patent holder is unable to
establish such a purpose, a court should presume that the purpose behind the
required amendment is such that prosecution history estoppel would apply."[41]
III.Answers
to the En Banc Questions
A.
Question 1
For the purposes of determining whether an
amendment to a claim creates prosecution history estoppel, is "a
substantial reason related to patentability,"[42] limited to those amendments made to overcome
prior art under § 102 and § 103, or does "patentability" mean any
reason affecting the issuance of a patent?
We answer Question 1 as follows: For the purposes of determining whether an
amendment gives rise to prosecution history estoppel, a "substantial
reason related to patentability" is not limited to overcoming or avoiding
prior art, but instead includes any reason which relates to the statutory
requirements for a patent. Therefore, a narrowing amendment made for any reason
related to the statutory requirements for a patent will give rise to prosecution
history estoppel with respect to the amended claim element.
It is true that in Warner-Jenkinson the Supreme
Court focused on claim amendments made to overcome or avoid prior art. [43] However, there are a number of statutory
requirements that must be satisfied before a valid patent can issue and that
thus relate to patentability. In addition to satisfying the novelty and
non-obviousness requirements of 35 U.S.C. §§ 102 and 103, 35 U.S.C.A. §§ 102,
103, the claims must be directed to patentable subject matter and the claimed
invention must be useful, as set forth in 35 U.S.C. § 101. Additionally, the
first paragraph of 35 U.S.C. § 112 requires that the patent specification
describe, enable, and set forth the best mode of carrying out the invention, 35
U.S.C. § 112, ¶ 1, while the second paragraph of section 112 requires that the
claims set forth the subject matter that the applicant regards as his invention
and that the claims particularly point out and distinctly define the invention,
35 U.S.C. § 112, ¶ 2. The Patent Office will reject a patent application that
fails to satisfy any one of these statutory requirements.[44] And any one of these requirements may be a
ground for invalidating an issued patent.[45] An amendment related to any of these
statutory requirements is an amendment made for "a substantial reason
related to patentability."
The law has been clear that amendments made to
avoid prior art give rise to prosecution history estoppel.[46] In view of the functions of prosecution
history estoppel--preserving the notice function of the claims and preventing
patent holders from recapturing under the doctrine of equivalents subject
matter that was surrendered before the Patent Office--we see no reason why
prosecution history estoppel should not also arise from amendments made for
other reasons related to patentability, as described above. Indeed, the
functions of prosecution history estoppel cannot be fully satisfied if
substantial reasons related to patentability are limited to a narrow subset of
patentability issues. Rather, substantial reasons related to patentability
include 35 U.S.C. §§ 101 and 112 issues, as well as 35 U.S.C. §§ 102 and 103
issues.
While we do not believe that the Supreme Court
itself answered this question in Warner-Jenkinson, we do believe that our
answer is not inconsistent with Warner-Jenkinson. Warner-Jenkinson describes
prior cases as applying prosecution history estoppel "typically because
what [was previously claimed] . . . was encompassed within the prior art,"[47] but no language in Warner-Jenkinson limits
prosecution history estoppel to amendments made to avoid prior art.[48] Moreover, our approach is consistent with
Warner-Jenkinson's requirement that an amendment "does not necessarily
preclude infringement by equivalents of that element."[49] Thus, if a patent holder can show from the
prosecution history that a claim amendment was not motivated by patentability
concerns, the amendment will not give rise to prosecution history estoppel.
B.
Question 2
Under Warner-Jenkinson, should a
"voluntary" claim amendment--one not required by the examiner or made
in response to a rejection by an examiner for a stated reason--create
prosecution history estoppel?
We answer Question 2 as follows: Voluntary claim
amendments are treated the same as other amendments. Therefore, a voluntary
amendment that narrows the scope of a claim for a reason related to the
statutory requirements for a patent will give rise to prosecution history
estoppel as to the amended claim element.
Both voluntary amendments and amendments
required by the Patent Office signal to the public that subject matter has been
surrendered. There is no reason why prosecution history estoppel should arise
if the Patent Office rejects a claim because it believes the claim to be unpatentable,
but not arise if the applicant amends a claim because he believes the claim to
be unpatentable.
Our answer to this question is consistent with
the doctrine of argument-based estoppel. Arguments made voluntarily during
prosecution may give rise to prosecution history estoppel if they evidence a
surrender of subject matter.[50] There is no reason why an amendment-based
surrender of subject matter should be given less force than an argument-based
surrender of subject matter.
We also believe that our answer to this question
is consistent with Warner-Jenkinson. Although the Supreme Court spoke of
"required" amendments, the claim amendment at issue in
Warner-Jenkinson, the addition of the lower pH limit of 6, was not
"required" by the prior art rejection. The original claim recited an
ultrafiltration process.[51] The asserted prior art reference taught an
ultrafiltration process conducted at a pH of above 9.[52] The amended claim recited an ultrafiltration
process conducted "at a pH from approximately 6.0 to 9.0."[53] The parties did not dispute that the upper
pH limit of 9.0 was added to distinguish the prior art.[54] The Court, however, was unable to discern
the reason for the addition of the lower pH limit of 6.[55] Accordingly, the amendment at issue in
Warner-Jenkinson appears to have been voluntary with respect to the lower pH
limit. Nevertheless, the Court held that the amendment adding the lower pH
limit could give rise to prosecution history estoppel.[56]
C.
Question 3
If a claim amendment creates prosecution history
estoppel, under Warner-Jenkinson what range of equivalents, if any, is
available under the doctrine of equivalents for the claim element so amended?
We answer Question 3 as follows: When a claim
amendment creates prosecution history estoppel with regard to a claim element,
there is no range of equivalents available for the amended claim element.
Application of the doctrine of equivalents to the claim element is completely
barred (a "complete bar").
We think it is fair to say that the question of
the scope of equivalents available when prosecution history estoppel applies to
a claim element has not been directly addressed or answered by the Supreme
Court, at least in circumstances where the claim was amended for a known
patentability reason. In Warner-Jenkinson, the Court focused its attention more
on the circumstances under which prosecution history estoppel arises than on
the range of equivalents that might generally be available despite the
existence of prosecution history estoppel.[57] The Court did not discuss the upper pH limit
of 9.0, other than to note that the upper limit, which narrowed the claim, was
selected to overcome prior art.[58] The range of equivalents, if any, that could
be asserted for the upper pH limit was not discussed by the Court. The only
statements in Warner Jenkinson as to the range of equivalents that is available
when prosecution history estoppel applies are found in the Court's discussion
of unexplained amendments.[59] For those amendments, the Court held that
"prosecution history estoppel would bar the application of the doctrine
[of] equivalents as to that element."[60]
1. In cases before Warner-Jenkinson, the Supreme Court applied prosecution history estoppel to preclude a finding of infringement under the doctrine of equivalents, but the Court did not analyze the actual scope of equivalents that might be available when prosecution history estoppel applied, i.e., the extent of the subject matter surrendered by amendment. In Weber Electric Co. v. E.H. Freeman Electric Co.,[61] the patentee had amended his claim to an electric lamp socket to overcome prior art that taught a socket and electric bulb that were unlocked and locked together simply by rotation. The amended claim recited, instead, a bulb and socket combination that unlocked and locked by manual compressi