Doctrine of Equivalents Toolkit: Claim Charts, Estoppel Histories, and Ensnarement Analyses

How to use this toolkit

Doctrine of equivalents cases get decided on paper long before anyone argues them. These templates are designed to force the discipline the cases demand: limitation-specific analysis, record citations for the reason behind every amendment, and an explanation of why a difference is or is not substantial. Replace the [bracketed placeholders], and delete any row or section that does not apply. Mark drafts as privileged work product where appropriate, and remember that anything served or filed commits you.

For the doctrine, see The Doctrine of Equivalents and Prosecution History Estoppel: When a Patent Reaches Beyond Its Literal Words. For the step-by-step process, see Proving or Defeating Infringement Under the Doctrine of Equivalents: A Practical Guide. For a printable task list, see Doctrine of Equivalents Checklist: A Practical Checklist.

A running example. To show how the papers connect, several templates include a filled-in row from a hypothetical. Suppose Pellam Packaging owns a patent claiming a bottle capper with "a chuck having a magnetic clutch that limits applied torque." Ostrander Bottling Systems sells a capper whose chuck limits torque with a pneumatic clutch. Those names and facts are invented for illustration.

Table of contents

1. Element-by-element equivalents chart
2. Estoppel history table
3. Festo rebuttal memo
4. Disclosure-dedication worksheet
5. Ensnarement and hypothetical claim workup
6. Limit-by-limit decision matrix
7. Infringement contention language bank
8. Expert declaration outline
9. Cross-examination questions on way and limits
10. Summary judgment motion skeleton
11. Rule 50 motion on equivalents
12. Jury instructions and special verdict
13. Prosecution remarks clause bank
14. Design-around record memo

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1. Element-by-element equivalents chart

Purpose: forces a limitation-specific comparison and exposes thin "way" evidence. Owner: litigation associate with the technical expert. Timing: first version before contentions; update after Markman and after expert discovery.

Filled example (hypothetical).

Drafting notes.

• Equivalence applies to each element, not the invention as a whole, under Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U.S. 17 (1997). The same case says the role played by each element informs the analysis, which is why this chart includes a row for it.
• Each prong must be substantially the same, with "way" of particular importance, under VLSI Technology LLC v. Intel Corp., 87 F.4th 1332 (Fed. Cir. 2023).
• In chemical and biological cases, replace the function-way-result rows with an insubstantial-differences analysis, including structural similarity, where that fits better. See Mylan Institutional LLC v. Aurobindo Pharma Ltd., 857 F.3d 858 (Fed. Cir. 2017) and UCB, Inc. v. Watson Laboratories Inc., 927 F.3d 1272 (Fed. Cir. 2019).
• Known interchangeability is an important factor under Graver Tank & Mfg. Co. v. Linde Air Products Co., 339 U.S. 605 (1950), measured at the time of infringement. But a strong interchangeability record for the patentee may also prove foreseeability if there was a narrowing amendment. Fill in Template 2 before relying on it.

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2. Estoppel history table

Purpose: a complete record of how each limitation changed and why. This is the first document to prepare in any equivalents matter. Owner: associate or patent agent, reviewed by prosecution-experienced counsel. Timing: before pleading or answering.

Add these checklist rows beneath the table for each limitation:

• Rewritten from dependent to independent? [Yes or no, date, parent canceled?]
• Closely related claims canceled? [claim number, subject matter, reason]
• Restriction election? [groups, with or without traverse, reasons]
• Argument statements (separate from amendments)? [quote, page]
• Family members with related statements? [application number, quote, page]
• Post-grant statements? [IPR number, paper, quote]

Filled example (hypothetical).

Drafting notes.

• Follow the four-question sequence from Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 344 F.3d 1359 (Fed. Cir. 2003) (en banc): narrowing, reason, territory, rebuttal.
• Adding a limitation counts as narrowing, and so does rewriting a dependent with cancellation of the parent, under Honeywell International Inc. v. Hamilton Sundstrand Corp., 370 F.3d 1131 (Fed. Cir. 2004) (en banc). See also Felix v. American Honda Motor Co., 562 F.3d 1167 (Fed. Cir. 2009).
• Canceling a closely related claim can count as narrowing under Colibri Heart Valve LLC v. Medtronic CoreValve, LLC, No. 23-2153 (Fed. Cir. July 18, 2025). That is why the table asks about it.
• Argument-based estoppel needs a clear and unmistakable surrender, under Conoco, Inc. v. Energy & Environmental International, L.C., 460 F.3d 1349 (Fed. Cir. 2006). Amgen Inc. v. Coherus BioSciences Inc., 931 F.3d 1154 (Fed. Cir. 2019) confirms that earlier responses count even if the last one before allowance said something different.
• Record the reason for the amendment only as an outsider could read it. Your own theory goes in Template 3.

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3. Festo rebuttal memo

Purpose: internal evaluation (or the skeleton of a brief) on whether the presumption of surrender can be rebutted for a specific equivalent. Owner: senior associate or partner. Timing: before contentions for the patentee; before moving for summary judgment for the accused infringer.

MEMORANDUM (Privileged and confidential; attorney work product) To: [lead counsel] From: [author] Date: [date] Re: Presumption of surrender, [patent no.], claim [x], limitation "[language]"; asserted equivalent: [feature]

1. Bottom line. [Presumption applies / does not apply. Likely rebutted / not rebutted, because...]

2. Narrowing amendment. On [date], in response to [rejection basis] over [reference], the applicant changed "[before]" to "[after]." [Literal scope narrowed because...]

3. Reason related to patentability. [Stated reason, record cite. If unexplained, Warner-Jenkinson presumption and what the record shows.]

4. Surrendered territory. Between "[before]" and "[after]" lies [description]. [Accused feature] falls [inside/outside] because [reason].

5. Equivalent as defined. For both infringement and foreseeability, the equivalent is: [one precise statement].

6. Unforeseeability. Date of amendment: [date]. Was the equivalent known in the field as defined by the original claim scope? Evidence: [publications, products, sales, cited art]. Did the original claim literally cover it? [Yes/No]. Conclusion: [ ].

7. Tangentiality. Objectively apparent reason from the record: [ ]. How the equivalent departs from the literal limitation: [ ]. Same axis or different axis: [ ]. Did the applicant amend this same element? [ ]. Did the cited art contain the equivalent? [ ]. Is there any explanation for the entire amendment, including each added limitation? [ ]. Conclusion: [ ].

8. Some other reason. [Shortcoming of language? Is the equivalent in the prior art?] Conclusion: [ ].

9. Argument-based estoppel, separately. [Statements, whether clear and unmistakable.]

10. Evidence plan. Record only for items 3, 7, and (where possible) 8. Expert or documentary evidence for item 6.

11. Risks and recommendation.

Filled example for item 7 (hypothetical). The objectively apparent reason, from page 7 of the response, is that Hale's ratchet wears and spikes torque, and the magnetic clutch does not. Ostrander's pneumatic clutch departs from the limitation by using air-loaded friction instead of magnetism. Pellam would argue that the amendment targeted ratchets and the resulting wear and spikes, so the means of slip is a different axis. Ostrander would answer that the applicant chose the word "magnetic," that it amended the very element at issue, that pneumatic clutches were in a reference cited in that same action, and that a narrower amendment excluding ratchets was available. Under the cases below, Pellam has a colorable argument with a serious obstacle, and the cited pneumatic reference may be fatal.

Drafting notes.

• The burden is on the patentee, under Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722 (2002), and by a preponderance, per Integrated Technology Corp. v. Rudolph Technologies, Inc., 734 F.3d 1352 (Fed. Cir. 2013). Rebuttal is a question of law for the court.
• Foreseeability: Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 493 F.3d 1368 (Fed. Cir. 2007) says suitability for the amended claim's purpose need not be known. Use the same equivalent for both tests under Honeywell International, Inc. v. Hamilton Sundstrand Corp., 523 F.3d 1304 (Fed. Cir. 2008). See also Duramed Pharmaceuticals, Inc. v. Paddock Laboratories, Inc., 644 F.3d 1376 (Fed. Cir. 2011).
• Tangentiality framing: Ajinomoto Co. v. International Trade Commission, 932 F.3d 1342 (Fed. Cir. 2019). Patentee-side authorities: Eli Lilly & Co. v. Hospira, Inc., 933 F.3d 1320 (Fed. Cir. 2019), Insituform Technologies, Inc. v. CAT Contracting, Inc., 385 F.3d 1360 (Fed. Cir. 2004), Regents of the University of California v. Dakocytomation California, Inc., 517 F.3d 1364 (Fed. Cir. 2008), and Intervet Inc. v. Merial Ltd., 617 F.3d 1282 (Fed. Cir. 2010). Defense-side authorities: Biagro Western Sales, Inc. v. Grow More, Inc., 423 F.3d 1296 (Fed. Cir. 2005), Felix, Integrated Technology, Cross Medical Products, Inc. v. Medtronic Sofamor Danek, Inc., 480 F.3d 1335 (Fed. Cir. 2007), Little Giant Ladder Systems, LLC v. Tricam Industries, Inc., No. 24-2115 (Fed. Cir. Feb. 5, 2026) (nonprecedential), and Actelion Pharmaceuticals Ltd v. Mylan Pharmaceuticals Inc., No. 24-1641 (Fed. Cir. May 13, 2026).
• Lilly warns against bright lines, and also says an amendment narrowing the same element is a powerful indication against tangentiality. A careful memo acknowledges both.

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4. Disclosure-dedication worksheet

Purpose: decide whether the specification gave away the equivalent. Owner: associate with a technical reader. Timing: with Template 2.

Search terms to run: the accused material or structure, its class name, "alternative," "alternatively," "instead," "other," "for example," "such as," "may be," "preferred," "preferably," "not limited to."

Drafting notes.

• The rule is from Johnson & Johnston Associates Inc. v. R.E. Service Co., 285 F.3d 1046 (Fed. Cir. 2002) (en banc), following Maxwell v. J. Baker, Inc., 86 F.3d 1098 (Fed. Cir. 1996).
• Specificity comes from PSC Computer Products, Inc. v. Foxconn International, Inc., 355 F.3d 1353 (Fed. Cir. 2004), and the "alternative" requirement from Pfizer, Inc. v. Teva Pharmaceuticals USA, Inc., 429 F.3d 1364 (Fed. Cir. 2005). SanDisk Corp. v. Kingston Technology Co., 695 F.3d 1348 (Fed. Cir. 2012) brings those two together, as Actelion quotes.
• Actelion rejects any requirement that disclosed alternatives be mutually exclusive.
• The patentee's remedies, if time remains, are a continuation or a broadening reissue under 35 U.S.C. § 251, as Johnson & Johnston notes.
• A court can decide this on the pleadings, under Eagle Pharmaceuticals Inc. v. Slayback Pharma LLC, 958 F.3d 1171 (Fed. Cir. 2020).

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5. Ensnarement and hypothetical claim workup

Purpose: test whether a claim literally covering the accused product could have been allowed. Owner: patent litigator with prosecution experience; technical expert. Timing: patentee before serving contentions; accused infringer as soon as art is in hand.

Part A. Drafting

Part B. Testing against the art

Part C. Filing position

• Who produced the art: [accused infringer, under its burden of production]
• Who carries persuasion: [patentee]
• When decided: [before trial / post-verdict bench hearing]
• Evidence: [expert declarations, references]
• Ruling requested: [ ]

Filled example (hypothetical). "a magnetic clutch that limits applied torque" becomes "a [non-ratcheting] clutch that limits applied torque." That is risky. Unless every magnetic clutch is also non-ratcheting, "non-ratcheting" narrows the claim in some respect, which Jang forbids, and it reads as a term drafted to steer around Hale rather than to reach Ostrander's clutch. The safer versions are "a clutch that limits applied torque," or a broadening that replaces "magnetic" with "magnetic or pneumatic." Pellam prefers the second because it is closer to the actual claim. The hypothetical must clear the Ibsen reference, which mentions a pneumatic clutch in a capper. If Ibsen shows a pneumatic clutch on a capper with every other claimed element, the claim is anticipated and the theory is barred.

Drafting notes.

• The method comes from Wilson Sporting Goods Co. v. David Geoffrey & Associates, 904 F.2d 677 (Fed. Cir. 1990), which also explains that the actual claims remain valid regardless of the outcome.
• The court decides, per DePuy Spine, Inc. v. Medtronic Sofamor Danek, Inc., 567 F.3d 1314 (Fed. Cir. 2009).
• No narrowing, and no duty on the court to fix a flawed hypothetical: Jang v. Boston Scientific Corp., 872 F.3d 1275 (Fed. Cir. 2017), Streamfeeder, LLC v. Sure-Feed Systems, Inc., 175 F.3d 974 (Fed. Cir. 1999).
• Burdens: Interactive Pictures Corp. v. Infinite Pictures, Inc., 274 F.3d 1371 (Fed. Cir. 2001). Method: Ultra-Tex Surfaces, Inc. v. Hill Brothers Chemical Co., 204 F.3d 1360 (Fed. Cir. 2000), Intendis GmbH v. Glenmark Pharmaceuticals Inc., 822 F.3d 1355 (Fed. Cir. 2016).
• For gathering and qualifying art, see Prior Art Toolkit: Search Protocols, Invalidity Charts, and On-Sale Bar Investigations.

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6. Limit-by-limit decision matrix

Purpose: a one-page view for client reporting and strategy. Owner: lead counsel. Timing: update at each stage.

Reading the matrix.

Drafting note. A limitation may have little or no range of equivalents even without a formal bar. As Moore U.S.A., Inc. v. Standard Register Co., 229 F.3d 1091 (Fed. Cir. 2000) puts it, all limitations are not entitled to an equal scope of equivalents. Rate honestly. Also check Freedom to Operate and IP Clearance Toolkit: Clearing the Path Before You Launch if the matrix is being used in a clearance setting.

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7. Infringement contention language bank

Purpose: clear, specific disclosures. Owner: associate with expert input. Timing: per local patent rules, and promptly after any adverse construction.

Clause A: limitation-specific contention (patentee).

Limitation [x]: "[language]." [Accused product] does not literally include [feature] under [the Court's / Defendant's proposed] construction, and in the alternative infringes under the doctrine of equivalents. [Accused feature], located at [cite], performs the function of [function]. It does so in substantially the same way, by [specific mechanism], as the claim requires, because [reason]. It achieves substantially the same result of [result], as shown by [source]. The differences, namely [each difference], are insubstantial because [reason].

Clause B: reservation that is honest about what it is.

Discovery on [specific subject] is outstanding. [Patentee] will supplement this contention within [x] days of production of [documents], in accordance with [rule].

Clause C: deficiency letter (accused infringer).

Your contentions state that [limitations] are met "under the doctrine of equivalents" with no statement of what in [product] is the equivalent, or how it performs the function, way, and result of the limitation. [Rule] requires more. Please serve specific contentions by [date]. Otherwise we will seek relief, including an order precluding the theory.

Clause D: interrogatory (accused infringer).

For each limitation You contend is met under the doctrine of equivalents, separately state: (a) the structure, step, or code You contend is the equivalent; (b) the function, way, and result of the limitation and of that equivalent, and why they are substantially the same, or the basis on which You contend the differences are insubstantial; (c) all facts and documents supporting Your contention; (d) the basis on which You contend prosecution history estoppel does not apply; and (e) the text of any hypothetical claim on which You rely to show the asserted range of equivalents does not ensnare the prior art.

Clause E: non-infringement response.

[Product] does not include "[limitation]" literally or by an equivalent. [Plaintiff]'s theory is barred by prosecution history estoppel because [amendment, date, reason, territory]. It is further barred by the disclosure-dedication rule [cite], and would vitiate the limitation because [reason]. [Product] operates in a substantially different way because [mechanism].

Drafting notes. Check the forum's rules on contentions. Requirements differ by district and judge, and a catch-all sentence risks losing the theory. Tie the statements of function, way, and result to Texas Instruments Inc. v. Cypress Semiconductor Corp., 90 F.3d 1558 (Fed. Cir. 1996). In a non-patent-local-rule district, seek the same disclosure through Fed. R. Civ. P. 26 and scheduling orders under Fed. R. Civ. P. 16. See also Section 112 Toolkit: Claim Support Charts, Invalidity Contentions, and Expert Declarations for how contentions are organized on the invalidity side.

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8. Expert declaration outline

Purpose: structure for a patentee's opening report or summary judgment declaration, adaptable for a rebuttal report. Owner: testifying expert, with counsel. Timing: per schedule; start early, because testing may be needed.

1. Qualifications and assignment. Include why the witness is a person of at least ordinary skill. Compensation and materials considered, per Fed. R. Civ. P. 26(a)(2)(B).
2. Legal standards as provided by counsel. Equivalence is limitation by limitation, from the perspective of a skilled person, at the time of infringement. Intent is not relevant. Burden on the patentee.
3. Person of ordinary skill and state of the art.
4. The patent and the role of each limitation in the claim.
5. Claim construction applied.
6. The accused product at the operational level. Describe how it actually works, with sources, including diagrams or code walk-throughs.
7. Literal analysis for context.
8. Equivalents analysis, for each limitation:
   • a. What is not literally met.
   • b. Accused element.
   • c. Function: claimed and accused. Why they match.
   • d. Way: claimed and accused, step by step. Why they match, and specifically how any differences do not change the manner of operation.
   • e. Result: claimed and accused, with data. Why they match.
   • f. Insubstantial differences analysis, as a cross-check or as the main test in the chemical arts.
   • g. Known interchangeability as of infringement, with sources.
   • h. Explanation of each difference identified by the defendant.
   • i. Why this theory does not read out the limitation. What remains excluded.
9. Foreseeability, if relevant to Festo. State of the art at the amendment date, with the equivalent defined as in section 8.
10. Hypothetical claim and prior art (if asked): why the hypothetical claim is patentable over the art, under anticipation and obviousness standards.
11. Exhibits and reservation of supplement.

Sample "way" paragraph (hypothetical).

In the claimed clutch, torque is transmitted across a gap by the magnetic force between two faces, and transmission stops when the load exceeds that force, because the faces then slip relative to each other. In Ostrander's clutch, torque is transmitted through contact between two faces held together by air pressure, and transmission stops when the load exceeds the friction at that pressure, because the faces then slip. In both, an externally set force determines the slip point, and in both, slip occurs without any part breaking or disengaging. The differences are as follows. Ostrander's faces touch, so they wear, at a rate I calculated to be [x] over [y] cycles, which is [immaterial/material] in this application because [reason]. Ostrander's clutch needs an air supply, which [reason]. For these reasons, and in the context of this claim, where the limitation's role is [role], I conclude that [conclusion].

Drafting notes.

• Particularized testimony and linking argument are required regardless of the technology: NexStep, Inc. v. Comcast Cable Communications, LLC, 119 F.4th 1355 (Fed. Cir. 2024). Lear Siegler, Inc. v. Sealy Mattress Co., 873 F.2d 1422 (Fed. Cir. 1989) and AquaTex Industries, Inc. v. Techniche Solutions, 479 F.3d 1320 (Fed. Cir. 2007) are the sources of the requirement.
• A statement that something operates "in substantially the same way," with only a parenthetical, was too thin in Akzo Nobel Coatings, Inc. v. Dow Chemical Co., 811 F.3d 1334 (Fed. Cir. 2016). "A design choice" failed in VLSI. Testimony on the percentage of instructions stored on-chip, without addressing the underlying difference between cache and permanent memory, failed in Gemalto S.A. v. HTC Corp., 754 F.3d 1364 (Fed. Cir. 2014).
• Avoid opinions on legal limits except as asked, and confine them to facts that the court may consider. Tangentiality is decided on the record. See Fed. R. Evid. 702 and Expert Witness Toolkit.
• For software patents, attach a data and control flow diagram. If the claim is under 35 U.S.C. § 112(f), analyze the disclosed algorithm separately, under WMS Gaming Inc. v. International Game Technology, 184 F.3d 1339 (Fed. Cir. 1999).

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9. Cross-examination questions on way and limits

Purpose: build the record for Rule 50 and appeal. Owner: trial team. Timing: expert deposition and trial.

On the way prong.

• You agree the claim requires [limitation]?
• Show the jury where in your report you state the way in which [limitation] performs its function.
• Now show where you state how [accused element] performs its function.
• What physically or logically happens at step [x] in each? What is different?
• You testified that it is a design choice. A design choice between what, and what follows from choosing one over the other?
• Why did [defendant's] engineers choose [alternative]? Did you consider those reasons?

On breadth and vitiation.

• Under your opinion, what would not be equivalent to [limitation]?
• Would [other structure] be equivalent? Why not?
• If the limitation were deleted from the claim, how would your analysis change?

On file history (deposition, or a bench hearing, more than a jury).

• Have you read the file history? Were you asked about the [date] amendment?
• At the time of the amendment, were you aware of [alternative]? Was it in [reference]?

On hypothetical claim (bench or deposition).

• Who drafted the hypothetical claim you analyzed? Does it include anything the actual claim lacks?
• Have you compared it against [reference]? What element is missing?

Drafting notes. The test from Malta v. Schulmerich Carillons, Inc., as quoted in NexStep, is what and why, for each prong. Questions on "what would not be equivalent" draw on Tronzo v. Biomet, Inc., 156 F.3d 1154 (Fed. Cir. 1998), where the theory would have made any shape equivalent. For deposition planning, see Expert Deposition Toolkit: Outline Frameworks, Reliance Material Requests, and Rule 26 Protection Maps. Do not raise the file history before a jury without a plan, because estoppel is for the court.

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10. Summary judgment motion skeleton

Purpose: a motion on legal limits, leading with the strongest. Owner: lead associate. Timing: per schedule, ideally early if estoppel is clean.

DEFENDANT'S MOTION FOR PARTIAL SUMMARY JUDGMENT OF NO INFRINGEMENT UNDER THE DOCTRINE OF EQUIVALENTS

Introduction. [Plaintiff] concedes [product] does not literally include "[limitation]." Its equivalents theory fails as a matter of law, for [n] independent reasons. [One sentence each.]

Undisputed facts. [Numbered facts with file-history cites: original claim; rejection; amendment; remarks; specification text; prior art.]

Legal standard. [Fed. R. Civ. P. 56.] "[W]here the evidence is such that no reasonable jury could determine two elements to be equivalent, district courts are obliged to grant partial or complete summary judgment." Warner-Jenkinson, 520 U.S. at 39 n.8. Legal limits on the doctrine are for the court. Id.

Argument. I. Prosecution history estoppel bars the theory. A. The amendment narrowed the claim for reasons of patentability. B. [Feature] lies in the surrendered territory. C. [Plaintiff] cannot rebut the presumption. (1) Foreseeable. (2) Not tangential. (3) No other reason. II. The specification dedicated [feature] to the public. III. The theory would vitiate the limitation. No reasonable jury could find [why]. IV. The asserted range would ensnare the prior art. [Plaintiff] bears the burden, and [its hypothetical claim fails or is absent]. V. [Plaintiff] has no particularized evidence of equivalence.

Conclusion. [Specific relief, claim by claim.]

Drafting notes.

• The Rule 56 standard is at Fed. R. Civ. P. 56. Vitiation is a no-reasonable-jury conclusion under Deere & Co. v. Bush Hog, LLC, 703 F.3d 1349 (Fed. Cir. 2012), so do not use "binary" language. UCB, quoting Cadence Pharmaceuticals Inc. v. Exela PharmSci Inc., 780 F.3d 1364 (Fed. Cir. 2015), says it is not a threshold exception. See also Freedman Seating Co. v. American Seating Co., 420 F.3d 1350 (Fed. Cir. 2005) and DePuy Spine, Inc. v. Medtronic Sofamor Danek, Inc., 469 F.3d 1005 (Fed. Cir. 2006).
• Avoid arguing foreseeability alone outside the Festo context. See Ring & Pinion Service Inc. v. ARB Corp., 743 F.3d 831 (Fed. Cir. 2014).
• Be precise about the record: cite pages of the certified file history, and attach them. Use Pharma Tech Solutions, Inc. v. LifeScan, Inc., 942 F.3d 1372 (Fed. Cir. 2019) as a model for treating amendment and argument together.

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11. Rule 50 motion on equivalents

Purpose: preserve and present the challenge to an equivalents verdict. Owner: trial team. Timing: Rule 50(a) before submission to the jury; Rule 50(b) within the rule's deadline after judgment.

DEFENDANT'S MOTION FOR JUDGMENT AS A MATTER OF LAW OF NO INFRINGEMENT UNDER THE DOCTRINE OF EQUIVALENTS

Under Federal Rule of Civil Procedure 50(a), [Defendant] moves for judgment as a matter of law that [product] does not infringe claim[s] [x] of the [patent] under the doctrine of equivalents. [Plaintiff] has been fully heard, and there is no legally sufficient evidentiary basis for a reasonable jury to find for it, for the following reasons.

1. No particularized testimony and linking argument for [limitation]. [Witness]'s testimony at [Tr. x:y] does not explain why the way in which [accused element] [function] is substantially the same as the claimed [limitation]. [Quote the testimony.] [Plaintiff] offered no other evidence on this point.

2. Function / result. [If contested, same format.]

3. Prosecution history estoppel. [Amendment, date, territory.] The issue is for the Court.

4. Disclosure-dedication. [Specification cite.]

5. Vitiation. Treating [feature] as equivalent would render "[limitation]" ineffective because [reason].

6. Ensnarement. [Hypothetical claim, art, or absence of proof.] [Plaintiff] bears the burden.

7. Dependent claims. [Claims x to y fall with claim 1, and independently for these reasons.]

Drafting notes.

• The standard and renewal procedure are in Fed. R. Civ. P. 50. The regional circuit's standard applies, as in NexStep (Third Circuit) and Colibri (Ninth Circuit). Check how your circuit treats grounds not raised at the Rule 50(a) stage. Post-Trial Toolkit: Rule 50 Renewals, New Trial Briefs, and Remittitur Analyses covers the renewal.
• Quote the testimony. VLSI turned on a transcript passage. Set yours out the same way.
• Estoppel and other legal limits can be decided on Rule 50 and reviewed de novo, as in Colibri. Also request written findings if a bench ruling is reserved.
• If the jury gave a limitation-specific verdict, tie each ground to that question.
• If liability falls, address enhanced damages and fees that rest on it. Integrated Technology vacated treble damages for that reason. See also 35 U.S.C. § 284.

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12. Jury instructions and special verdict

Purpose: limit the risk of an overall-similarity verdict and make review possible. Owner: trial team. Timing: per the pretrial order. Use model instructions if your court requires them, and modify as needed.

Sample instruction.

If you find that [product] does not literally include a requirement of the claim, you must decide whether it includes an equivalent of that requirement. You must make this decision separately for each requirement. It is not enough that [product] as a whole is similar to the invention. A part or step in [product] is an equivalent if a person of ordinary skill in the field would consider the differences between it and the requirement to be insubstantial, at the time of the alleged infringement. One way to decide this is to ask whether the part or step performs substantially the same function, in substantially the same way, to obtain substantially the same result, as the requirement. Whether [defendant] intended to copy or to avoid the patent is not relevant to this question. [Plaintiff] has the burden of proving equivalence by a preponderance of the evidence.

Sample verdict question.

For claim [x], as to each requirement listed below, did [Plaintiff] prove by a preponderance of the evidence that [product] contains the requirement, either literally or by an equivalent?

Requirement [a]. Literally: Yes __ No __. If No, by an equivalent: Yes __ No __. Requirement [b]. Literally: Yes __ No __. If No, by an equivalent: Yes __ No __.

Drafting notes. Authority: Warner-Jenkinson, 520 U.S. at 39 n.8, and Fed. R. Civ. P. 49. For the rest of trial materials, see Jury Trial Toolkit: Voir Dire, Openings, Exhibits, and Instructions. Keep estoppel, dedication, and ensnarement out of the jury's instructions, and request findings from the court.

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13. Prosecution remarks clause bank

Purpose: reduce argument-based risk and create a usable record for tangentiality. Owner: prosecution counsel. Timing: every response to an action.

Clause A: narrow distinction.

[Reference] does not disclose [specific feature], at least because [reason tied to reference's teaching]. Claim [x], as amended, recites [feature], which is not shown.

Clause B: objective reason for the amendment.

Claim [x] has been amended to recite [limitation] to distinguish [reference]'s [specific feature]. The amendment concerns [aspect], and does not concern [other aspects].

Clause C: non-reliance on other features.

Other differences between the claims and the cited references may exist. Applicant's discussion of certain differences is not a statement about other features, and does not limit any other claim.

Clause D: continuation note.

Applicant reserves the right to pursue claims of the same or different scope in this or a related application.

Avoid: "the present invention requires," "the critical feature is," "only," "must," "unlike all prior art," and "particular," unless you mean it.

Drafting notes.

• Coherus turned on repeated emphasis of "particular" combinations. Assertions can create estoppel even if not required for allowance.
• These clauses do not undo a clear surrender, and the Festo presumption attaches to the amendment regardless. Clause B gives the court something on the record for the tangentiality inquiry, which focuses on the objectively apparent reason. How much weight general reservations receive is not settled, so do not rely on them alone.
• For dependents and cancellations, consider Honeywell and Colibri before accepting an examiner's suggestion. See Patent Prosecution Toolkit: A Roadmap and Research Guide for prosecution materials generally.
• For a design application, keep alternatives in separate applications where possible, per Pacific Coast Marine Windshields Ltd. v. Malibu Boats, LLC, 739 F.3d 694 (Fed. Cir. 2014).

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14. Design-around record memo

Purpose: contemporaneous, business-grade record of what was changed and why, for a company designing around a patent. Owner: engineering lead, with counsel reviewing. Timing: during the redesign, not after a demand letter.

Drafting notes.

• Keep legal analysis in a separate privileged memo. Keep the engineering record factual, because it may be produced. If privileged notes are produced by mistake, the steps are in Clawback Toolkit: 502(d) Orders, Clawback Notices, and Privilege Review Protocols.
• Intent is not an element, but Warner-Jenkinson recognizes the difficulty of telling a copyist from an incremental innovator, and treats known interchangeability as the objective fact that counts. Honest engineering explanations bear on "way."
• Avoid phrases such as "same as theirs but outside the claim." Say what differs, and why.
• The clearance side is covered in Freedom to Operate and IP Clearance Toolkit: Clearing the Path Before You Launch. For notice letter responses, see Willfulness Toolkit: Notice Letter Responses, Opinion of Counsel Engagements, and Read Factor Analyses. For venue issues if a suit follows, see Patent Venue Toolkit: Venue Discovery, Rule 12(b)(3) Motions, and Section 1404 Transfer Papers.

This toolkit supplies general templates and should be adapted, with counsel, to the specific patent, record, and court.

Related Documents

Related Articles

• The Doctrine of Equivalents and Prosecution History Estoppel: When a Patent Reaches Beyond Its Literal Words: the doctrine these templates apply.
• Indirect and Divided Patent Infringement: Inducement, Contributory Liability, and the Akamai Problem: when equivalents theories run through induced infringement, as in Colibri.

Related Guides

• Proving or Defeating Infringement Under the Doctrine of Equivalents: A Practical Guide: the process and timing these papers support.
• Preparing for a Markman Hearing: A Practical Guide: claim construction, which sets the baseline.

Related Checklists

• Doctrine of Equivalents Checklist: A Practical Checklist: phased tasks that correspond to these templates.
• Post-Trial Motion Checklist: A Practical Checklist: post-trial deadlines for Template 11.

Related Toolkits

• Claim Construction Toolkit: Charts, Briefs, Expert Declarations, and Hearing Materials: charts and briefs for claim construction.
• Section 112 Toolkit: Claim Support Charts, Invalidity Contentions, and Expert Declarations: claim support charts and invalidity contentions, from this batch's Section 112 cluster.
• Patent Venue Toolkit: Venue Discovery, Rule 12(b)(3) Motions, and Section 1404 Transfer Papers: venue discovery and transfer papers, from this batch's venue cluster.
• Clawback Toolkit: 502(d) Orders, Clawback Notices, and Privilege Review Protocols: clawback papers for design-history productions, from this batch's privilege cluster.
• Prior Art Toolkit: Search Protocols, Invalidity Charts, and On-Sale Bar Investigations: searching for and qualifying art used in Template 5.
• Expert Witness Toolkit: general expert materials.
• Post-Trial Toolkit: Rule 50 Renewals, New Trial Briefs, and Remittitur Analyses: Rule 50 renewals and new trial briefs.
• Freedom to Operate and IP Clearance Toolkit: Clearing the Path Before You Launch: clearance before launch.
• Patent Prosecution Toolkit: A Roadmap and Research Guide: prosecution research and roadmap.