Infringement, Doctrine of equivalents & prosecution history estoppel

Infringement, Doctrine ofequivalents & prosecution history

estoppel

Sumesh Reddy -NALSAR Visiting Faculty

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estoppelMr.Sumesh Reddy-

Patent rights

• Right to exclude others

• A patent is not a grant of a right to make, use or sell. Atlas Powder Co. v. E.I. du Pont


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use or sell. Atlas Powder Co. v. E.I. du Pont de Nemours & Co

• Quid pro quo of Patent protection- grant of patent in return for full disclosure

Literal infringement

• In order to find that a patent has been infringed every element of the patented claim must be found in the infringing device

• A copyist can avoid literal infringement by


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• A copyist can avoid literal infringement by making changes so that his or her device does not have the exact elements disclosed in the patented claim

• Any discrepancy between the patented claim and the accused device will negate a finding of literal infringement

Claim construction

• Defining the meaning of claim terms to determine what scope the patent covers

• The clear meaning of the words will prevail


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• The clear meaning of the words will prevail• The patent drafter is his own lexicographer• Intrinsic evidence: claims, specifications,

file history• Extrinsic evidence: trail testimony,

unrelated applications or patents

Equivalents

• In order to protect patent owners from copyists stealing the patented invention by making small or insubstantial changes to the invention, the Supreme Court established the principle of


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Supreme Court established the principle of infringement under the doctrine of equivalents

• This doctrine allows a court to find infringement if the elements of the accused device are insubstantially different from those disclosed in the patent

What is an equivalent

• 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


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insubstantial or interchangeable

• 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.

Why equivalents

• The doctrine of equivalents is a judicial construction which recognizes the frailties of the written word.


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of the written word.

• an infringer appropriates an invention, not words

Rationale for the doctrine

• Supreme Court in Graver Tank & Manufacturing Co. v. Linde Air Products Co.:

• ‘Courts have recognized that to permit imitation of a patented invention which does not copy every


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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 the unscrupulous copyist to make unimportant 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’

Graver Tank & Manufacturing Co. v.Linde Air Products. Co.

• 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.


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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.

Graver Tank (facts)

• Electric welding compositions. The patented composition was a combination of alkaline earth metal silicate and calcium


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alkaline earth metal silicate and calcium fluoride. The accused composition used silicates that were not of an alkaline earth metal

Function/way/result

• 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


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in substantially the same way to obtain the same result.’

• The test is necessarily premised on the underlying assumption that each of the "elements" recited in the claim is found somewhere in the accused product or process

Reverse doctrine of equivalents

• Thus, where an invention relies on the fundamental concept embodied in a patent but is more sophisticated than the patented


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but is more sophisticated than the patented device due to "a significant advance," the accused device does not infringe by virtue of the reverse doctrine of equivalents

Pennwalt

• The all-elements rule provides that every limitation of a claim is material, and that an accused device lacking a corresponding


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accused device lacking a corresponding element, or an equivalent thereof, for every limitation cannot infringe the claim, even under the doctrine of equivalents. Pennwalt Corp. v. Durand-Wayland, Inc

Pennwalt & the all elements rule

• The rule in Pennwalt requires that a comparison be made between the function/way/result of the proposed infringing element and the function/way/result of the claimed element


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function/way/result of the claimed element

• Proof of infringement under the doctrine of equivalents has required an element-by-element comparison between the claimed invention and the accused product or process.

Rationale for the all-elementsrule

• The Supreme Court has recognized for more than a century that the public is entitled to make, use, or sell devices that


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entitled to make, use, or sell devices that lack one or more elements corresponding to the limitations of a patent's claims, or their equivalents.

Rationale for the all-elementsrule

• Where an applicant for a patent to cover a new combination is compelled by the rejection of his application by the patent-office to narrow his claim by the


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office to narrow his claim by the introduction of a new element, 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

Rationale from an early case

• If it be a claim to a combination, and be restricted to specified elements, all must be regarded as material, leaving open only the


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regarded as material, leaving open only the question whether an omitted part is supplied by an equivalent device or instrumentality Shepard v. Carrigan

Warner-Jenkinson restates therule

• Each element contained in a patent claim is deemed material to defining the scope of the patented invention, and thus the doctrine of


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patented invention, and thus the doctrine of equivalents must be applied to individual elements of the claim, not to the invention as a whole.

A rule to determine equivalenceInsubstantial differences

• A claim element is equivalently present in an accused device if only insubstantial differences distinguish the missing claim


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differences distinguish the missing claim element from the corresponding aspects of the accused device. Hilton Davis Chemical Co. v. Warner-Jenkinson Co

Sun Studs, Inc. v. ATA Equip. Leasing Inc.,

• One-to-one correspondence of components is not required

• One-to-one correspondence often is not the


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• One-to-one correspondence often is not the case in certain technologies, such as electronics, where hardware and software implementations produce the same functions and results using different components or semiconductor structures.

Potential for the infringer

• Based on the "all elements" or "all limitations" rule, the absence of even a single element (or limitation), both literally


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single element (or limitation), both literally and equivalently, should preclude a finding of infringement and so represents a strong potential defense available to an accused infringer.

Potential for the infringer

• When an alleged infringer proves by a preponderance of the evidence that even a single claim element is missing in the


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single claim element is missing in the accused product or process, then the "all elements" or "all limitations" rule dictates that the accused product or process cannot infringe the claim at issue.

The Substituted ElementApproach of Slimfold

• Example of a case in which a physically different element which had been substituted for the least significant claim


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substituted for the least significant claim element was found to be non-equivalent

• A Styrofoam wedge was substituted for the recited releasable latch means in the claimed bifold metal door assembly

Slimfold

• The Federal Circuit essentially held that because they are physically different elements, they must operate in a different


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elements, they must operate in a different way.

• Exactly the same function and result were achieved with a physically different element which performed in a different way

The Foreseeability rule

• Sage Products, Inc. v. Devon Industries, IncDoctrine of Equivalents will not reach a device that is a variation of the claimed invention that would have been foreseeable by a skilled patent


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would have been foreseeable by a skilled patent attorney

• As between the patentee who had a clear opportunity to negotiate broader claims but did not do so, and the public at large, it is the patentee who must bear the costs of its failure to seek protection for this foreseeable alteration of its claimed structure

Dedication Rule

• Subject matter that was alternatively disclosed but unclaimed is deemed to have been affirmatively dedicated to the public (Maxwell v. J. Baker, Inc)

• For example, the Doctrine of Equivalents would


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• For example, the Doctrine of Equivalents would not extend a claim literally directed to a screw to include a nail if the specification discloses both a screw and a nail and no issued claim literally reads on a nail

• The Dedication Rule, precludes a patentee from using the Doctrine of Equivalents to protect subject matter that was disclosed by the patentee but not claimed.

The Dedication Rule and itsOrigins

• Miller v. Brass Co.: In 1860, a patent issued to Joshua E. Ambrose for a lamp purporting to eliminate the need for a chimney by using a pair of domes or reflectors arranged one above the other


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domes or reflectors arranged one above the other instead

• Patent also disclosed a single dome together with a chimney

• After the original claim failed, it was discovered that this would be an improvement over the prior art & both patentee as well as others started using this method

The dedication rule

• Fifteen years after issuance, the patent owner sought and obtained reissue of the patent, including a claim that read on a single dome plus chimney combination


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chimney combination• The patent owner sued a competitor• The Supreme Court held that the original

patentee's disclosure of, and subsequent failure to claim, the "single dome plus chimney" structure during prosecution of the original patent constituted a dedication of the unclaimed invention to the public domain

Extension of Miller to thedoctrine of equivalents

• Did not apply the Dedication Rule in a Doctrine of Equivalents context, it dealt with the validity and scope of claims in a reissue

• In Graver Tank, the Supreme Court found that the


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• In Graver Tank, the Supreme Court found that the Doctrine of Equivalents is available for a disclosed but unclaimed embodiment

• But the alternative embodiment disclosed there was in fact claimed in other claims that issued with the patent, but were later determined to be invalid as inoperative. Thus, the alternative disclosure in Graver Tank was not unclaimed at the time the patent in suit issued

Extension of Miller to thedoctrine of equivalents

• Graham v. John Deere Co (While the sealing feature was not specifically claimed in the Livingstone patent, it was disclosed


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in the Livingstone patent, it was disclosed in the drawings and specifications. Under long-settled law the feature became public property)

Unique Concepts, Inc. v.Brown

• An inventor obtained a patent for an assembly of border pieces used to attach a fabric wall covering to a wall

• The claimed assembly included linear border


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• The claimed assembly included linear border pieces and "right angle corner border" pieces

• The accused device used an assembly of just one type of piece, each piece being linear with mitered ends cut at a 45 degree angle to be connected linearly or at right angles, as may be required.

Unique Concepts, Inc. v.Brown

• The specification refers to "improvised corner pieces" similar to the infringing pieces as an alternative

• It is also well-established that subject matter


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• It is also well-established that subject matter disclosed but not claimed in a patent application is dedicated to the public. If Unique intended to claim mitered linear border pieces as an alternative to its right angle corner border pieces, it had to persuade the examiner to issue such a claim. . . . Unique failed to do so

Rationale for the extension of therule

• Such a result would encourage an applicant to escape examination of a more broadly-claimed invention by filing narrow claims


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claimed invention by filing narrow claims and then, after grant, asserting a broader scope of the claims based on a statement in the specification of an alternative never presented in the claims for examination

Patent & claim drafting strategiessuggested by the two rules

• Add a broad means plus function claim-Section 112, paragraph 6 provides that a claim of a combination in means plus


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claim of a combination in means plus function format is construed to cover the corresponding structure, material or acts described in the specification and the equivalents thereof

Drafting & prosecution strategies

• A broad means plus function claim designed to correspond to each portion of the specification might help survive a Dedication Rule limitation

• Avoid unnecessary disclosure of unclaimed


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• Avoid unnecessary disclosure of unclaimed species or alternative embodiments

• The initial disclosure of alternative embodiments that might later be abandoned or left unclaimed will likely result in a Dedication Rule limitation

Strategies

• Avoid Rigid Limitations- the use of broadening modifiers, where appropriate, may go a long way toward assisting a


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may go a long way toward assisting a plaintiff's argument that the variation was was foreseen and claimed

• It is as much a mistake to claim too little as it would be to claim too much initially, risking a Prosecution History Estoppel.

The Formstein Test

• 1. If an allegedly infringing device or process forms part of the prior art, there can be no infringement;

• 2. If an allegedly infringing device or process


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• 2. If an allegedly infringing device or process would have been obvious over the prior art, there can be no infringement; and

• 3. 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.

Rationale for the approach

• A patentee should not be able to obtain, under the doctrine of equivalents, coverage which he could not lawfully have obtained


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which he could not lawfully have obtained from the PTO by literal claims

A case from Britain

• Merrell Dow Pharmaceuticals Inc. and Another v. H.N. Norton & Co. Ltd.

• Plaintiffs first obtained a patent on the antihistamine,“Terfenadine,”


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• Plaintiffs first obtained a patent on the antihistamine,“Terfenadine,”

• Later they discovered, through research, that 99.5% of it was metabolized in the liver

• Took a Patent over the active acid metabolite formed in the liver, MDL 16,455

A case from Britain

• When the patent on “Terfenadine” expired, competitors began manufacturing a generic substance


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substance

• Plaintiffs sued on the later filed application covering the acid metabolite

• Issue: is the invention new, or already known to the prior art

Lord Hoffmann’s analogy

• It is part of the prior art if the prior art discloses information sufficient to enable the public to work the invention

• Imagine a scientist telling an Amazonian Indian


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• Imagine a scientist telling an Amazonian Indian “We have found that the reason why the bark is good for fevers is that it contains an alkaloid with a rather complicated chemical structure which reacts with the red corpuscles in the bloodstream. It is called quinine.” The Indian replies: “That is very interesting. In my tribe, we call it the magic spirit of the bark.”


• Does the Indian know about quinine? My Lords, under the description of a quality of the bark which makes it useful for treating fevers, he obviously does. I do not think it


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fevers, he obviously does. I do not think it matters that he chooses to label it in animistic rather than chemical terms. He knows that the bark has a quality which makes it good for fever and that is one description of quinine.


• What does it mean to know something, so that it can be part of the state of the art? The quinine example shows that there are


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quinine example shows that there are descriptions under which something may in a relevant sense be known without anyone being aware of its chemical composition or even that it has an identifiable molecular structure.

The Hypothetical Claim Analysis(an American approach)

• The patentee proposes a hypothetical claim (i.e. a claim not found in the patent per se but which has disclosure support therein)


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but which has disclosure support therein) that is broad enough to encompass literally the accused infringing composition or device.

The Hypothetical Claim Analysis

• If that hypothetical claim could have been allowed by the U.S. Patent & Trademark Office ("PTO") in view of the prior art as of the effective filing date of the patent (not


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the effective filing date of the patent (not the date of the alleged infringement), then the prior art does not preclude the patentee from asserting that the accused product or process infringes the patent under the doctrine of equivalents.

The Hypothetical Claim Analysis

• Conversely, if any of the prior art references, alone or in combination, indicate that the proposed hypothetical claim was


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that the proposed hypothetical claim was not novel or would have been obvious to one of ordinary skill in the art, then the prior art is a bar to the asserted range of equivalents

Burden of proof

• Initial burden is on the patentee to prove that the proposed hypothetical claim is, in fact, novel and non-obvious over the prior art

• When a patentee has made a prima facie case of


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• When a patentee has made a prima facie case of infringement under the doctrine of equivalents by proposing a hypothetical claim that encompasses the accused composition or device, the accused infringer then has the burden of coming forward with evidence showing that the claim is unpatentable over the prior art.

The patentee may not…

• Redraft a patent claim in toto, both narrowing and broadening an asserted claim at the same time. Rather, only broadening of


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at the same time. Rather, only broadening of a claim is permitted, and no limitations may be added to the claim to provide patentability

The patentee may…

• Expressly cancel at least some of the limitations in the asserted claim

• The canceled limitations will be the ones


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• The canceled limitations will be the ones that are not found in the accused product or process.

Conditions for drafting ahypothetical claim

• Only the limitations, which are not literally met by the alleged infringement, should be amended. For example, if a patent claim includes elements a, b, and c, and the alleged infringement includes a, b,


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and c, and the alleged infringement includes a, b, and c’, where c’ is close to c, the hypothetical claim may not set limitations on, or amend, language regarding a and b, because claim elements a and b literally read on the accused device.

Why only amendments to elementsthat do not infringe literally

• Amending original claim language that literally reads on the alleged infringement can lead to drafting a hypothetical claim


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can lead to drafting a hypothetical claim that covers the accused device, but avoids prior art.

Prosecution history estoppel


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What is ?

• Prosecution history refers to the history of the patent before the U.S. Patent & Trademark Office.


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Trademark Office.

• This history is embodied in the written record contained in the patent file wrapper maintained by the United States Patent & Trademark Office.

What is Prosecution HistoryEstoppel?

• If a patent applicant admits during prosecution before the Patent Office that a claim does not cover certain subject matter, then that party may not later assert that the claim covers that subject


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not later assert that the claim covers that subject matter in subsequent litigation.

• The doctrine of prosecution history estoppel arises as a legal defense to an assertion of infringement under the doctrine of equivalents.

When does it arise ?

• Prosecution history estoppel only arises where (1) there is no literal infringement; (2) the patent owner asserts infringement by equivalents; and (3) the accused infringer affirmatively asserts the


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the accused infringer affirmatively asserts the defense of prosecution history estoppel prevents the Patent holder from asserting the doctrine of equivalents on the basis that the relevant subject matter has been disclaimed during prosecution

When does it arise ?

• Prosecution history estoppel applies most frequently where a patent applicant amends or cancels claims rejected by the Patent Office as unpatentable based upon prior art


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unpatentable based upon prior art• Some decisions have extended prosecution history

estoppel to amendments entered for other purposes, and to arguments made by the applicant.

• “Unmistakable assertions made by the applicant … also may operate to preclude the patentee from asserting equivalency….”- Builders Concrete,

An early case

• The inventor filed an application for a skirt protector that did not have any reference to pleats

• This application was rejected based upon a


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• This application was rejected based upon a prior patent that made no reference to pleats

• Filed an amended specification that described a skirt protector with a “plaited or fluted border.”

Early case

• Infringement action against a party who sold skirt protectors that did not have a plaited or fluted border

• “The file wrapper and contents … make it clear


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• “The file wrapper and contents … make it clear that the claim and specification of the Macdonald patent must be construed to include, as their language requires, a fluted or plaited band or border as one of the essential elements of the invention”

Early history

• If an applicant, in order to get his patent, accepts one with a narrower claim than that contained in his original application he is bound by it. If dissatisfied with the decision rejecting his


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dissatisfied with the decision rejecting his application, he should pursue his remedy by appeal

• The earliest cases focused primarily on limiting the construction of the patent based upon narrowing amendments made to secure the patent grant.

Flexible bar of the FederalCircuit

• Hughes Aircraft Co. v. United States- Amendment of claims is a common practice in prosecution of patent applications. No reason or warrant exists for limiting application of the doctrine of


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for limiting application of the doctrine of equivalents to those comparatively few claims allowed exactly as originally filed and never amended. Amendments may be of different types and may serve different functions. Depending on the nature and purpose of an amendment, it may have a limiting effect within a spectrum ranging from great to small to zero.

Estoppel & claim construction

• When courts conclude that a claim should be narrowly construed based upon disclaimers made in the prosecution history.

• Thus, during claim construction, courts often go


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• Thus, during claim construction, courts often go beyond deciding what a claim covers and address what the claim cannot cover. In effect, therefore, courts apply estoppel concepts as part of a claim construction analysis.

Warner-Jenkinson Co. v. HiltonDavis Chem. Co

• The 1952 act did not destroy the doctrine of equivalence

• Supreme Court decision in Graver Tank


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• Supreme Court decision in Graver Tank remains good law

• Upheld the ‘all elements’ rule of Pennwalt

Warner-Jenkinson & Prosecutionhistory estoppel

• Hilton Davis received a patent (the ‘746 patent) in 1985, which discloses an improved purification process for certain


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improved purification process for certain food dyes

• The process involves the “ultrafiltration” of dye through a porous membrane at pH levels between 6.0 and 9.0.

Warner-Jenkinson

• The inventors limited their claims to this range during prosecution of the patent at the Patent Office, in response to a prior art


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Patent Office, in response to a prior art rejection based upon the earlier Booth patent. The Booth patent disclosed an ultrafiltration process operating at a pH above 9.0.

Warner-Jenkinson

• In 1986, Warner Jenkinson developed its own ultrafiltration process, which operated at a pH level of 5.0

• Hilton Davis brought suit for patent infringement


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• Hilton Davis brought suit for patent infringement

• The Court noted that the addition of the lower pH level of 6.0 was not done to avoid the prior art, and thus, did “not necessarily preclude infringement by equivalents of that element.”

Rebuttable presumption

• In such instances, however, the Court held that the patent owner had the burden to establish the reason for any amendment required during patent prosecution


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prosecution

• Where no explanation is established, however, the court should presume that the PTO had a substantial reason related to patentability for including the limiting element added by amendment.

Substantial reason related topatentability

• Warner Jenkinson did not specifically address whether a amendment made to overcome a sec.112 rejection or for other


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overcome a sec.112 rejection or for other reasons gives rise to prosecution history estoppel

• Should the presumption also apply to remarks made to distinguish prior art?

What must the Patentee show

• The patentee must show what was amended and why those amendments were made. The patentee also must show that the reasons for


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patentee also must show that the reasons for the amendment should not give rise to an estoppel because the amendment was unrelated to patentability

• Patentee’s must contend that amendments were made to address minor informalities,

FESTO CORPORATION, v.SHOKETSU KINZOKU

KOGYO KABUSHIKI CO.,


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KOGYO KABUSHIKI CO.,LTD

Questions decided in the En banchearing (Q 1)

• 1. For the purposes of determining whether an amendment to a claim creates prosecution history estoppel, is "a


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prosecution history estoppel, is "a substantial reason related to patentability," 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?

Q 2

• 2. Under Warner-Jenkinson, should a "voluntary" claim amendment--one not required by the examiner or made in


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required by the examiner or made in response to a rejection by an examiner for a stated reason--create prosecution history estoppel?

Q 3

• 3. If a claim amendment creates prosecution history estoppel, under Warner-Jenkinson what range of equivalents, if any, is


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what range of equivalents, if any, is available under the doctrine of equivalents for the claim element so amended?

Q 4

• 4. When "no explanation for a claim amendment is established,", thus invoking the presumption of prosecution history


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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?

Answer to Q 1

• 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


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"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.

Answer to Q 2

• Voluntary claim amendments are treated the same as other amendments

• Both voluntary amendments and


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• Both voluntary amendments and amendments required by the Patent Office signal to the public that subject matter has been surrendered.

Answer to Q 3

• When a claim amendment creates prosecution history estoppel with regard to a claim element, there is no range of


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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

Answer to Q 3

• Flexible bar approach- prosecution history estoppel "may have a limiting effect" on the doctrine of equivalents "within a spectrum ranging from great to small to zero.“


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from great to small to zero.“

• The need for certainty as to the scope of patent protection

• Virtually impossible to predict before the decision on appeal where the line of surrender is drawn

Answer to Q 4

• Where no explanation is established, . . . . prosecution history estoppel would bar the application of the doctrine of equivalents as


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application of the doctrine of equivalents as to that element

"DESIGNING AROUND"VALID U.S. PATENTS


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VALID U.S. PATENTS

Judicial justification fordesigning around

• Intentional designing around the claims of a patent is not by itself a wrong which must be compensated by invocation of the doctrine of equivalents. Designing around


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doctrine of equivalents. Designing around patents is, in fact, one of the ways in which the patent system works to the advantage of the public in promoting progress in the useful arts, its constitutional purpose Slimfold Mfg. Co. v. Kinkead Industries, Inc

Judicial justification fordesigning around

• Hilton Davis Chemical Co. v. Warner-Jenkinson Co- The ability of the public successfully to design around to use the patent disclosure to design a product or process that does not infringe,


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design a product or process that does not infringe, but like the claimed invention, is an improvement over the prior art is one of the important public benefits that justify awarding the patent owner exclusive rights to his invention. Designing around is the stuff of which competition is made and is supposed to benefit the consumer

Patent Resources Group

• Course taught by PRG for strategies to be followed in validly designing around U.S Patents


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Patents

• Course offers several step-by-step procedures for a design around exercise which were based on the Federal Circuit law

Professor Kayton’s nine steps

• 1. List the claims in diminishing order of breadth.

• 2. (Optional) Proceed to eliminate the broadest and successively less broad claims by finding prior art to invalidate them.


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prior art to invalidate them.

• 3. With solely the broadest valid claim in mind, consult with technical and marketing experts to select the one, two or more claim-recited elements that is/are of least significance and could be omitted from a commercial product.

Steps 4 & 5

• 4. If step 3. is successful, write an infringement opinion stating that the proposed product is noninfringing under Pennwalt

• 5. If step 3. is impossible to achieve using your


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• 5. If step 3. is impossible to achieve using your technical and marketing experts, select one claim-recited element of least importance and then substitute an element that performs the same function but is physically or chemically (as the case may be) as different as possible from that of the claimed element so as not to be considered an insubstantial change.

Steps 6 & 7

• 6. If step 5. is successful, write a step 4. noninfringement opinion but rely on Slimfold v.Kinkead

• If steps 3. and 5. bomb out, i.e., "designing


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• If steps 3. and 5. bomb out, i.e., "designing around" means having to virtually slavishly copy the claim, then select the least important claim-recited element and have experts explain how to change it physically or chemically (as the case may be) so as to force it to function in a different way (from what is recited in either the specification or claim) while producing precisely the same result.

Steps 8 & 9

• 8. If step 7. is successful, write a step 4. noninfringement opinion.

• 9. If unable to succeed in achieving any one of steps 3., 5. or 7., your technical and marketing


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steps 3., 5. or 7., your technical and marketing experts are gloriously incompetent or in the patentee's employ. They should be fired, and relegated to an appropriate institution. Hire new experts, and start over at step 1.

Documents

Infringement, Doctrine of equivalents & prosecution history estoppel