Why is it important to perform detail analysis of prosecution history for infringement and validity/invalidity analysis of a patent.

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Prosecution History Analysis

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Table of Contents
• Why PH/File Wrapper Analysis.
• Extracting File Wrapper
• US Federal Courts
• Warner-Jenkinson Co. v. Hilton Davis Chemical Co.
• Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.
• Doctrine of Equivalence
• Prosecution History Estoppel (PHE)
• Amendment Estoppel
• Argument Estoppel
• Other Estoppel Considerations
• Prosecution History Estoppel Flow Chart
• QA

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Why PH/File Wrapper Analysis
In United States patent law, the record of the examination of a patent application is encapsulated in file wrapper,
including
• The original application itself,
• Responses made by the examiner, and
• Amendments made by the applicant to address objections raised by the examiner
INFRINGEMENT
• Determination of the proper scope of the claims and it prevents the scope of the claims from including any subject
matter the inventor surrendered during prosecution.
• The Prosecution History Estoppel.
Sections of file wrapper:
• NOA : Notice of allowance - Novelty determination
• CLM : Claims - Changes made in claims by the applicant
• REM : Applicants Arguments made in response to office actions (Final or Non Final)
• PEFR : Applicant’s response to Pre-Exam Formalities - Responses to, Missing parts, Notice of Incomplete
Application, Sequence Compliance Notice, Omitted Items, Corrected Application Papers Notice
• CTRS : Requirement for Restriction/Election – double patenting – elect claims for patenting and restrict claims for
divisional filing.
• CTNF : Non Final rejection – first OA
• CTFR : Final Rejection – Second OA
• RCEX : Request for continued examination - continued prosecution after the patent office has issued a "final"
rejection.
• DIST : Terminal Disclaimer - Patent Term Adjustment
• ABN : Abandonment - To relinquish the rights to an invention.

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Why PH/File Wrapper Analysis

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Extracting File Wrapper
1. Use PAIR to pull up information on the patent under review, then select the “Image File Wrapper” tab.
2. Next use the browser’s search result highlighting to find the prosecution history documents of interest.
3. Once all desired documents have been selected, activate the PDF button in the top row and save this PDF file (with whatever name you find helpful)
so you can review its contents.
4. Review the downloaded PDF file. While it is helpful to have context of the examiner’s rejection rationale, it is only important what the applicant (or
representative) files, argues, and amends.

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US Federal Courts
• The Supreme Court of the United States
The Supreme Court is the highest court in the federal Judiciary.
Congress has established two levels of federal courts under the
Supreme Court: the trial courts and the appellate courts.
• District (Trial) Courts
The United States district courts are the trial courts of the federal
court system. Within limits set by Congress and the Constitution, the
district courts have jurisdiction to hear nearly all categories of federal
cases, including both civil and criminal matters
• Appellate Courts
A court of appeals hears appeals from the district courts located
within its circuit, as well as appeals from decisions of federal
administrative agencies.

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Warner-Jenkinson Co. v. Hilton Davis Chemical Co.
Warner-Jenkinson Company, Inc. v. Hilton Davis Chemical Co., 520 U.S. 17 (1997)
Issue
Is the doctrine of equivalents still in force? How is the plaintiff's amendment to figure into the problem?
Background
Warner Jenkinson (Petitioner)and Hilton Davis (Respondent) both manufacture dyes from which impurities must be removed. Hilton
Davis’s (Respondent) '746 patent," which issued in 1985, discloses an improved purification process involving the "ultrafiltration" of dye
through a porous membrane at pH levels between 6.0 and 9.0. The inventors so limited their claim's pH element during patent
prosecution after the patent examiner objected because of a perceived overlap with the earlier "Booth" patent, which disclosed an
ultrafiltration process operating at a pH above 9.0. In 1986, Warner Jenkinson (Petitioner)developed its own ultrafiltration process,
which operated at a pH level of 5.0. Hilton Davis (Respondent) sued for infringement of the '746 patent, relying solely on the "doctrine of
equivalents," under which 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. Graver Tank & Mfg. Co. v. Linde Air Products Co., 339 U. S. 605, 609. Over petitioner's objections that
this is an equitable doctrine and is to be applied by the court, the equivalence issue was included among those sent to the jury, which
found, inter alia, that Warner Jenkinson (Petitioner)infringed upon the '746 patent. The District Court, among its rulings, entered a
permanent injunction against petitioner. The en banc Federal Circuit affirmed, holding that the doctrine of equivalents continues to
exist, that the question of equivalence is for the jury to decide, and that the jury had substantial evidence from which to conclude that
petitioner's process was not substantially different from the process disclosed in the '746 patent.
Court’s Decision
The Court, in an opinion by Justice Clarence Thomas, held that the doctrine of equivalents had not been eliminated by changes to the
patent statute. Instead, the Court determined that the United States Congress would have explicitly stated that they were eliminating the
doctrine if that was their intent. The Court enunciated a test for amendments, finding that if the plaintiff can prove the reason for the
amendment was not to limit the patent, then infringement was still possible. The case was remanded to the trial court to determine if the
plaintiff could explain his lower pH limit.

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Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.
Festo Corp. v Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722 (2002)
Issue
Whether any amendment to a patent application that narrowed a patent claim to comply with the Patent Act creates an absolute bar to
equivalents for the particular claim limitation that was narrowed by the amendment.
Background
Festo Corporation (petitioner) possessed patents for an industrial device. After Festo began marketing its device, Shoketsu Kinzoku
Kogyo Kabushiki Co. (SMC, respondents) entered the market with a device that used one two-way sealing ring and a nonmagnetizable
sleeve. Festo Corporation already owned two similar patents (although their initial patent application was rejected) for this industrial
device. Festo filed suit, claiming that SMC's device was sufficiently similar that it infringed Festo's patents under the doctrine of
equivalents. Festo's claim had been amended during prosecution for, at the very least, compliance with 35 U.S.C. §112, and thus Shoketsu
claimed that prosecution history estoppel should bar Festo from asserting equivalents.
1. The United States District Court for the District of Massachusetts held that Festo's amendments were not made to avoid prior art, and
therefore the amendments were not the kind that give rise to estoppel.
2. A panel of the Federal Circuit affirmed. 72 F. 3d 857 (1995).
3. The Supreme Court granted certiorari, vacated, and remanded in light of an intervening decision in Warner-Jenkinson v. Hilton Davis
Chemical Co.. After a decision by the original panel on remand, 172 F. 3d 1361 (1999),
4. the Federal Circuit ordered rehearing en banc, 187 F. 3d 1381 (1999). The court sitting en banc held that claim amendments made for
compliance with the Patent Act presented a complete bar to claiming equivalents.
Court’s Decision
The Supreme Court vacated the ruling made by the Federal Circuit, holding that such amendments do not create an absolute bar, but
instead must be examined in light of the reason for the change. In the unanimous opinion, Justice Kennedy explained that it was not
whether prosecution history estoppel applied to amendments, but to what extent the amendment surrendered coverage of the claim. If
the change was made to clarify a translation, for example, the inventor should suffer no reduction in rights. But if the change was made to
keep the patent from overlapping with another patent, then the applicant will be presumed to have given up the right to complain about
anything broader than the patent claim itself.
In particular, the court held that patentee's decision to narrow claims through amendment in order to comply with the Patent Act
automatically assumes surrender of the territory between the original claim and the amended claim, i.e., a presumption of surrendering
all equivalents for the particular claim limitation that was narrowed by the amendment. The court thus placed the burden on the
applicant as to showing what equivalents were not surrendered.

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Doctrine of Equivalence
EQUIVALENTS
Under the DOE, the substantial equivalent of a claim not literally infringed, is a legally infringing equivalence, if it works in
1. substantially the same way,
2. to accomplish substantially the same result,
3. even though differ in name, form, or shape.
INVENTION : DOE permits the patent holder to assert that the patent covers not only the perceive device or process patented,
but also equivalent devices or processes.
SCOPE Of CLAIMS : DOE allows a court to hold a party liable for patent infringement even though the infringing device or process
does not fall within the literal scope of a patent claim, but nevertheless is equivalent to the claimed invention.
POSA : DOE applies if two elements are interchangeable and a POSA would have known that the elements were
interchangeable at the time of infringement.
DOE TEST
• Function-Way-Results Test (Triple Identity Test): Under the function-way-result test, an element in the accused device is
equivalent to a claim limitation if it performs substantially the same function in substantially the same way to obtain
substantially the same result.
• Insubstantial Differences Test: Under the insubstantial differences test, an element in the accused device is equivalent to a
claim limitation if the only differences between the two are insubstantial.
• Hypothetical Claim Test: To determine the scope of the doctrine of equivalents in light of the prior art, a court can consider a
"hypothetical claim" that literally recites the range of equivalents asserted to infringe. The pertinent question then becomes
whether that hypothetical claim could have been allowed by the PTO over the prior art.
LIMITATION
PHE : In the United States, prosecution history is available to public and can stop patentee to claim equivalents over the
surrendered scope of claims.
Disclosure Dedication Rule : applies when POSA can understand the unclaimed disclosed teaching upon reading the written
description, then that unclaimed matter has been dedicated to the public

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Doctrine of Equivalence
REVERSE DOCTRINE OF EQUIVALENTS
“[W]here a device is so far changed in principle from a patented article that it performs the same or similar function in a
substantially different way, but nevertheless falls within the literal words of the claim, the [reverse] doctrine of equivalents may
be used to restrict the claim and defeat the patentee’s action for infringement.”
CONTRADICTION
When a court expands a patent claim by using the doctrine of equivalents, however, the court contradicts the theory that patent
claims measure the coverage of the patent and define the invention.
To protect the integrity of the patent system, courts created the doctrine of prosecution history estoppel. This doctrine
precludes a patent holder in an infringement suit from construing the patent claim so that the claim recaptures breadth which
the patent holder gave up during prosecution.
Materials contained in the prosecution history will bar, or estop, the patent holder from asserting infringement.

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Prosecution History Estoppel (PHE)
The judge stops the patent owner from narrowing claims to get the patent issued, and then take a contrary position in court about the
meaning of the claims when trying to prove infringement with respect to an equivalence.
A court must regard every element in a claim as material, even if the prior art did not require the claim to include the element.
The prosecution history provides extrinsic evidence potentially useful for the construction of claims but irrelevant to the question of
equivalence.
Hierarchy of Evidence
1. Claims
2. Specification
3. Prosecution History
4. Treatises
5. Prior Art
6. Testimony
APPLYING DOE AND PH ESTOPPEL
1. Does the claimed invention differ from the alleged infringing device or process? If not, literal infringement precludes applying
prosecution history estoppel.
2. Are the invention and device or process sufficiently similar to be equivalents? If not, the doctrine of equivalents is inapplicable.
3. Once the court finds equivalence, infringement exists unless prosecution history estoppel applies. Thus, even equivalent processes
or devices may not infringe the patent because the doctrine of equivalents applies before and is secondary to prosecution history
estoppel.
CONTRADICTION
• Both prosecution history estoppel and the doctrine of equivalents cause de-emphasize the claims.
• Both doctrines appear to have functional benefits: prosecution history estoppel protects reasonable reliance and promotes the
primacy of the Patent Office; the doctrine of equivalents prevents obvious "design arounds."
• Both doctrines also have functional costs: prosecution history estoppel holds inventors responsible for knowing the prosecution
history of each patent; the doctrine of equivalents holds inventors responsible for knowing the current state of the art.

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Amendment Estoppel
Amendment-based prosecution history estoppel where a narrowing amendment is “made for a ‘substantial reason related to
patentability’ when the record does not reveal the reason for the amendment.”
PRESUMPTIONS
Narrowing Amendment Presumption: The patentee must provide evidence from the intrinsic record that the amendment was not made
for reasons of patentability. If the patentee successfully establishes that the amendment was not made for reasons of patentability, then
amendment estoppel does not apply.
Territory Surrender Presumption (TSP): Failure to rebut the narrowing amendment presumption, creates the territory surrender
presumption. The territory surrender presumption, presumes that the patentee has surrendered the entire (total) territory between the
original claim limitation and the amended claim limitation.
The patentee may rebut the presumption of total surrender by demonstrating that it did not surrender the particular equivalent in
question. If the rebuttal is successful with respect to a particular equivalent in question, then prosecution history estoppel does not apply
to that equivalent, and the allegedly infringing equivalent is analyzed for equivalence, under the DOE Test.
REBUTTING TSP PRESUMPTION PRONGS:
Unforseeability: Patentee must show that an alleged equivalent would have been "unforeseeable at the time of the amendment and
thus beyond a fair interpretation of what was surrendered.“ – using extrinsic evidence
Tangential-ness: Patentee must demonstrate that the rationale underlying the narrowing amendment bore no more than a tangential
relation to the equivalent in question, such as when the reason for the narrowing amendment was peripheral, or not directly relevant, to
the alleged equivalent.
Some other reason: This third criterion may be satisfied when there was some reason, such as the shortcomings of language, why the
patentee was prevented from describing the alleged equivalent when it narrowed the claim.

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Argument Estoppel
Argument-based prosecution history estoppel where the applicant explicitly indicates claim interpretation through arguments made in
office action responses; and
Explicit arguments made during prosecution to overcome prior art can lead to narrow claim interpretations.
Claim Construction: By distinguishing the claimed invention over the prior art, an applicant is indicating what the claims do not cover, he
is by implication surrendering such protection.
Arguments Negating Written Description: Patentee argues that the written description precludes a finding that an embodiment was
disclaimed because it is included in the definition. Reading the written description alone, this argument might be effective, but in light of
the prosecution history, which was generated after the written description was drafted, it is apparent that Patentee relinquished any
coverage of that embodiment.
Direct Infringement Analysis: Argument estoppel may limit a claim for purposes of literal infringement. Here, before reaching any
question of DOE, the court determined that the patentee had made clear and unequivocal statements that added a limitation not literally
present in the claim (never updating parity).
Reasonable Competitor Standard: It is not what the Patentee believed they were surrendering. The relevant inquiry is whether upon
reading the prosecution history a competitor would reasonably believe that the applicant had surrendered the relevant subject matter.
Multiple Reasonable Interpretations: When the inventors' statements made in the prosecution history are amenable to multiple
reasonable interpretations it would be proper to deem them as too ambiguous to result in argument estoppel.
ARGUMENTS CAUSING ESTOPPEL:
1. Arguments promoting patentability of a feature of the claim would estop patentee from asserting that claim against an embodiment
lacking that feature, Hoganas v. Dresser, 9 F.3d 948 (1993),
2. Arguments made in applicant’s IDS distinguishing the invention from the prior art are subject to estoppel law, Ekchian v. Home Depot,
Inc. 104 F.3d 1299 (1997),
3. Clear reliance on the preamble during prosecution to distinguish the claimed invention from the prior art transforms the preamble
into a claim limitation, Catalina, 289 F.3d at 808,
4. The patentee can’t argue in prosecution that a claim does not require a feature shown in the prior art and then assert that claim
against a commercial embodiment that has that feature, Watts v. XL,

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Other Estoppel Considerations
1. Infectious Estoppel: The estoppel affects all other claims that containing the affected limitation, whether or not that those other
claims were argued, original or amended, Glaxo v. Impax, 356 F.3d 1348 (2004),
2. Rewriting of dependent claims into independent form creates estoppel, Honeywell v. Hamilton, 370 F.3d 1131 (2004),
3. Cancellation of broader original independent claims creates presumption with respect to language allowed in narrower issued
claims, Honeywell v. Hamilton,
4. Assuming cancelled broader claims not issued in continuation, Haynes v. Jessop,
5. A new limitation in a claim as well as a further narrowed existing limitation, Honeywell v. Hamilton,
6. When preliminary amendment filed right before the first office action amendment estoppel applies because patentee failed to
overcome the presumption, Pioneer v. Micro, 330 F.3d 1352 (2003),
7. The mere fact that an amendment is voluntary rather than in reaction to a rejection, does not shield it from prosecution history
estoppel, Amgen v. Hoechst, 314 F.3d 1313 (2003),
8. In the face of a reply to an office action, when the examiner withdraws a substantive rejection and allows a claim without giving
reasons for allowance, it is reasonable to presume that the arguments related to patentability were persuasive, NPC v. Precast, 337
F.Supp. 2d 378 (2004),
9. Prosecution history estoppel cannot be avoided by filing a continuing application with narrowed claims rather than responding
directly to an outstanding rejection, Desper v. QSound, 157 F.3d 1325,
10. By stating definitively that their arguments were limited to a specific claim, applicant signaled to a POSA that those arguments did
not apply to the other unstated claims, Johnson v. Zebco, 175 F.3d 985 (1999).

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Other Estoppel Considerations
RELATED PATENTS ESTOPPEL EFFECTS:
1. Commonly owned patents with no priority relationship (i.e., they are not continuations, divisionals, or CIPs of a same ancestor
lineage) have no estoppel effects even when subject matter related and with a common inventor in their inventor sets, Abbott v. Dey,
287 F.3d 1097 (2002),
2. The prosecution history of family related patents(parents and grandparents) are relevant for determining the meaning of a same
claim term in different patents, Jonsson v. Stanley, 903 F.2d 812 (1990), but not the same subject matter described using different
claim terms in the family, Al-Site v. VSI, 174 F.3d 1308 (1999),
3. The argument estoppel is limited to those arguments necessary to overcome the prior art for the same term in the related family,
Middleton v. Minnesota Mining, 311 F.3d 1384 (2002),
4. New subject matter added by CIP child is not influenced by its ancestors, Tex. Digital v. Telegenix, 308 F.3d 1193 (2002).
5. Foreign Family Members: We do not read the Commission's decision to establish any estoppel related to the prosecution of foreign
family members, yet representations to foreign patent offices should be considered when they include relevant evidence for
evaluating equivalents. Tanabe v. ITC, 109 F.3d 726.

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Prosecution History Estoppel Flow Chart

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References
1. http://jolt.law.harvard.edu/articles/pdf/v13/oldNonPaginated(DONOTUSE)/13HarvJLTech465.pdf
2. http://www.richardspatentlaw.com/faq/examination/what-is-a-restriction-election/
3. http://www.bpmlegal.com/howtooa4.html
4. http://piersonpatentlaw.com/what-are-the-differences-between-a-non-final-and-a-final-office-action/
5. http://www.lawyers.com/site-search.html?s=terminal+disclaimer
6. https://supreme.justia.com/cases/federal/us/520/17/case.html
7. http://www.oyez.org/cases/2000-2009/2001/2001_00_1543