What Is a Patent Claim Chart and Why Does It Matter

You've received a patent infringement letter. Attached is a multi page document titled "Claim Chart" showing your product features next to patent claim language. Or perhaps you're a patent holder considering enforcement, and your solicitor tells you that you need a claim chart before sending a cease and desist letter.

What exactly is a claim chart? Why does it matter? And how do you tell if a claim chart is strong or weak?

In this article, we'll explain what claim charts are, why they're the foundation of patent infringement analysis, and how technical experts prepare them. We've prepared claim charts for patent enforcement, invalidity defences, and due diligence across software, AI, hardware, and telecommunications, and we'll show you what makes the difference between a compelling technical analysis and one that falls apart under scrutiny.

What Is a Claim Chart?

A claim chart is a structured analysis that maps each element of a patent claim to specific evidence in an accused product or system. It's the essential tool for proving—or disproving—patent infringement.

Patent infringement requires that the accused product contains every element of at least one patent claim. This is the "all elements rule" or "all limitations rule": miss a single element, and the infringement argument fails, regardless of how many other elements match.

In the UK, infringement requires that the alleged infringer does something within the scope of the claims as properly construed.¹ Section 125 of the Patents Act 1977 provides that an invention shall be taken to be that specified in a claim, interpreted by the description and drawings.² Similarly, in the US, the Supreme Court established in Warner-Jenkinson Co. v. Hilton Davis Chemical Co. that infringement analysis must proceed "on an element-by-element basis"—each limitation in a patent claim must be evaluated separately against the accused product.³

The claim chart is how you prove this element by element correspondence. It breaks down each claim limitation and shows, with specific verifiable evidence, whether and how the accused product includes that element.

Claim charts are used by both sides in patent disputes:

• Patent holders use claim charts to show infringement when asserting their patents
• Accused infringers use claim charts to demonstrate non-infringement or identify missing elements
• Both sides in invalidity challenges use claim charts to map prior art to patent claims

A claim chart isn't just a legal formality. It's the technical backbone of infringement analysis, forming the foundation for expert reports, deposition testimony, trial presentations, and settlement negotiations.⁴

Anatomy of a Claim Chart

The most common claim chart structure uses two or three columns:

Two-column format:

• Left column: Patent claim language, broken into individual elements
• Right column: Evidence from accused product showing each element

Three-column format:

• Left column: Patent claim elements
• Middle column: Evidence from accused product
• Right column: Analysis explaining how evidence maps to claim element

Here's a simplified example for a hypothetical software patent:

Claim 1: A method for filtering content comprising: (a) receiving user generated content; (b) analysing the content using a trained machine learning classifier to detect policy violations; and (c) blocking content identified as violating policies.

Claim Element	Accused Product Evidence	Analysis
(a) "receiving user-generated content"	Product documentation (User Guide, p.14): "Users submit posts, comments, and media through the upload interface." Screenshot shows upload form with text input and media attachment options.	The accused system receives user-generated content through multiple input mechanisms, satisfying this limitation.
(b) "analysing the content using a trained machine learning classifier"	Source code excerpt (moderator.py, lines 145-162): classifier = MLModel.load('content_model.pkl') followed by prediction = classifier.predict(content_features). Training logs (training_run_2024.log) show model trained on 500k labelled examples.	The system uses a trained ML classifier (neural network model loaded from file, trained on labelled dataset) to analyse content, meeting this element literally.
(c) "to detect policy violations"	API response JSON shows classification output: {"category": "harassment", "confidence": 0.94, "violates_policy": true}. System architecture diagram shows classifier outputs feed into policy enforcement module.	The ML classifier specifically detects policy violations, with output explicitly indicating violation status, satisfying this limitation.
(d) "blocking content identified as violating policies"	Database schema (content_moderation table) includes status field with values including "blocked". Query logs show: UPDATE content SET status='blocked' WHERE violates_policy=true. User-facing interface displays "This content has been removed for violating community guidelines."	Content classified as violating is blocked from public display through database status updates and UI enforcement, meeting this element.

Types of Evidence Used

Claim charts draw on various evidence sources, depending on what's available and what the claims require:

For software patents:

• Source code excerpts showing algorithmic implementation
• Configuration files and system logs
• API documentation and network traffic analysis
• Database schemas and queries
• User interface screenshots with functionality demonstrations

For hardware patents:

• Product teardown photographs and diagrams
• Circuit schematics and component specifications
• Chip die analysis and microscopy
• Product testing results

For all patents:

• Product specifications and technical documentation
• User manuals and installation guides
• Marketing materials (though these alone are weak evidence)
• Expert testing and reverse engineering analysis

The strength of evidence varies significantly. Source code provides definitive proof for software patents. Detailed technical specifications and teardown analysis are strong for hardware. Marketing materials and vague product descriptions are weak evidence that can be easily challenged.

Why Claim Charts Matter

The All Elements Rule

This is the foundation of patent infringement analysis: to prove literal infringement, every element of a patent claim must be present in the accused product. In the UK, Section 60(1) of the Patents Act 1977 establishes that infringement occurs when a person does certain acts in relation to the invention—but what constitutes "the invention" is defined by the claims as construed under Section 125.⁵

The UK Supreme Court in Actavis UK Ltd v Eli Lilly and Company 2017 UKSC 48 reaffirmed that patent claims must be interpreted to determine what the patentee intended to protect, with reference to the Protocol on the Interpretation of Article 69 EPC.⁶ Similarly, the US Supreme Court's Warner-Jenkinson decision requires that "the determination of equivalence should be applied as an objective inquiry on an element-by-element basis."³

There are no partial scores in patent infringement.

If a patent claim has five elements (A, B, C, D, E), and the accused product has A, B, C, and D—even if D is implemented brilliantly—there's no literal infringement if E is missing. The claim chart is how you prove all elements are present, or how you identify which element is missing.

We've reviewed enforcement letters containing claim charts that beautifully map four out of five elements and completely fail to address the fifth. The accused infringer's technical team spots the gap immediately. The entire infringement position collapses.

Where Claim Charts Are Used

Cease and desist letters and enforcement

A credible cease and desist letter includes a claim chart. Without one, the allegation is just assertion-easy to dismiss. The claim chart shows you've done the technical analysis and have specific evidence of infringement. In the UK, this is particularly important given the Unjustified Threats provisions under Sections 70A-70F of the Patents Act 1977—threatening patent infringement without proper basis can itself be actionable.⁷

Expert reports in litigation

Technical expert reports in patent litigation are built around claim charts. Whether the expert opines that infringement exists or doesn't exist, the foundation is the element-by-element claim chart analysis.

In the UK, expert evidence in patent cases must comply with CPR Part 35 and the IPEC Guide, which requires experts to provide opinions that are their genuine, independent views and are supported by specific evidence.⁸ In the US, federal courts require detailed infringement contentions early in litigation, including claim charts that map specific claim limitations to corresponding elements in the accused product.⁹

Inter partes review (IPR) and opposition proceedings

When challenging patent validity through IPR in the US or opposition proceedings in Europe, claim charts are required to map patent claims to prior art references.

For IPR petitions at the USPTO's Patent Trial and Appeal Board (PTAB), 37 CFR § 42.104(b)(4) requires petitioners to explicitly identify where each element of a challenged claim appears in the relied-upon prior art patents or printed publications.¹⁰ Since September 2025, the USPTO strictly enforces this requirement—petitioners cannot use general knowledge or expert declarations to fill gaps where claim elements are missing from prior art references.¹¹

At the EPO, opposition proceedings under Article 99 EPC require opponents to substantiate invalidity claims with full reasoning and evidence, mapping prior art to patent claims to demonstrate lack of novelty or inventive step.¹² Opposition must be filed within nine months of patent grant with complete supporting documentation.

In the UK, patent validity challenges before the Patents Court or IPEC similarly require detailed pleadings supported by evidence, with the defendant's statement identifying specific grounds and prior art relied upon.¹³

Licensing negotiations

Claim charts provide the technical basis for licensing demands. A strong claim chart with clear infringement evidence creates settlement pressure. A weak claim chart undermines royalty negotiations and invites the accused party to litigate rather than license.

Due diligence and freedom to operate

When acquiring companies, evaluating patent portfolios, or conducting freedom to operate analysis, claim charts assess infringement risks and patent value.

Settlement discussions

Strong claim charts simplify complex technical disputes. When both sides can see clear element-by-element evidence, the technical arguments narrow and commercial settlement discussions can progress more productively.

What Makes a Strong Claim Chart

Professional guidance on claim chart preparation emphasises several critical quality indicators that distinguish strong technical analysis from weak assertions.

1. Element-by-Element Granularity

Strong claim charts address each claim limitation separately and explicitly. The infringement analysis process requires "evidence matching" where every claim limitation must be matched to specific technical evidence, with explanations pointing directly to supporting documentation rather than speculative or unfounded interpretations.¹⁴

Grouping elements together or providing generic mappings undermines the element-by-element analysis required by UK and US courts.

Weak approach: "The product uses machine learning for content analysis (addressing claim elements 2-4)."

Strong approach: Three separate rows in the claim chart, each with specific evidence for elements 2, 3, and 4 individually, showing precisely how each limitation is met.

2. Specific, Verifiable Evidence

US federal court local patent rules require infringement contentions to "identify specifically where each limitation of each asserted claim is found within each accused instrumentality."⁹ In the UK, the IPEC Guide similarly requires that particulars of infringement identify with precision which claims are alleged to be infringed and by what acts.¹⁵

Best practice guidance emphasises that claim charts must "anchor every claim limitation to specific technical evidence" with "clear reasoning" connecting evidence to claim elements.¹⁶ Evidence should be documented with sufficient detail that it can be independently verified: file names, line numbers, page references, exhibit citations, and technical specifications.

Weak: "The product likely stores data in a database."

Strong: "Database schema documentation (Appendix A, p.12) shows users table with fields user_id, name, email, created_at, preferences. PostgreSQL query logs (Exhibit B, lines 1834-1847) demonstrate user data is written to this table on account creation via INSERT statement."

This level of specificity isn't just good practice—it's what court rules and expert report standards require.

3. Technical Accuracy

The claim chart must correctly describe both what the patent claims and how the accused product actually works. Professional guidance emphasises that accused product investigation should be "an investigatory exercise, not merely a document compilation exercise", requiring analysis of actual product functionality through teardowns, source code review, system testing, and technical documentation rather than relying solely on marketing materials.¹⁴

Technical accuracy is critical for expert report admissibility. Under the Daubert standard applied in US federal courts, expert testimony must be based on reliable methodology and sufficient facts or data.¹⁷ In England and Wales, expert evidence must meet the standards in Ikarian Reefer 1993 2 Lloyd's Rep 68, requiring that experts provide their independent opinion based on complete and accurate information.¹⁸

We regularly review claim charts prepared without sufficient technical expertise. They misunderstand the technology—asserting a product uses neural networks when it actually uses decision trees, claiming real-time processing when evidence shows batch processing, or mapping general capabilities to specific technical requirements without demonstrating the connection.

Technical errors destroy credibility. Once opposing counsel or their expert identifies one technical misstatement, every other assertion in the claim chart becomes suspect, potentially affecting the entire infringement analysis.

4. Claim Construction Awareness

Patent claim construction follows established hierarchies of evidence in both jurisdictions.

In the UK: The Supreme Court in Actavis v Eli Lilly held that two questions must be asked: (1) does the variant infringe any of the claims as a matter of normal interpretation (literal infringement)? and (2) if not, does the variant nonetheless infringe because it varies from the invention in a way which is immaterial?⁶ The court endorsed purposive construction, considering what a person skilled in the art would have understood the patentee to mean.

In the US: The Federal Circuit in Phillips v. AWH Corp. established that claim terms should be interpreted based on intrinsic evidence in this order of priority:¹⁹

1. The claim language itself — given ordinary meaning as understood by a person of ordinary skill in the art
2. The patent specification — described as "the single best guide to the meaning of a disputed term"
3. The prosecution history — communications between applicant and examiner, including amendments and arguments
4. Extrinsic evidence — dictionaries, technical treatises, expert testimony (secondary, cannot contradict intrinsic evidence)

A strong claim chart interprets terms consistently with how they're defined in the patent's intrinsic evidence. If the specification explicitly defines "machine learning model" to require supervised learning with labelled training data, the claim chart cannot map this element to an unsupervised clustering system, even though both could generically be called "machine learning". Because doing so contradicts the patent's own definition.

Failing to account for proper claim construction is a fundamental weakness. Claim charts that use ordinary dictionary meanings when the specification provides specific technical definitions, or that ignore prosecution history where the applicant narrowed claim scope to distinguish prior art, lead to incorrect infringement conclusions that won't survive scrutiny.

5. Addresses All Limitations (Structural and Functional)

Patent claims often include both structural limitations (components that must exist) and functional limitations (what those components must do). A claim limitation is "functional" when it recites a feature "by what it does rather than by what it is."²⁰

Both types of limitations must be addressed in claim charts. Showing that a component exists (structural) isn't sufficient if the claim also requires that component to perform a specific function. The claim chart must demonstrate both the structure and the function.

Weak mapping: Shows that a component exists but fails to demonstrate it performs the claimed function.

Example: Claim requires "classifier configured to identify spam messages based on content features and sender reputation scores." A weak claim chart might show that a classifier exists and processes messages. A strong claim chart shows:

• The classifier identifies spam specifically (not just categorises messages generally)
• It analyses content features (excerpts of feature extraction code)
• It incorporates sender reputation scores (database join to reputation table, reputation scoring logic)

6. Visual Clarity and Organisation

Effective claim charts are formatted for easy comprehension by judges, juries, and attorneys who may not have technical backgrounds.⁴ Clear tables, visual aids, diagrams, and aesthetically organised information make complex technical analysis accessible.

Strong vs Weak Claim Chart Comparison

Characteristic	Weak Claim Chart	Strong Claim Chart
Element coverage	Groups multiple elements together; some elements unaddressed	Each element in separate row with distinct evidence
Evidence specificity	"The product likely uses a database"	"PostgreSQL schema (Appendix A, p.12) shows users table..."
Source material	Relies primarily on marketing brochures	Source code, technical docs, test results, teardowns
Technical language	Vague: "uses machine learning"	Precise: "convolutional neural network (ResNet-50 architecture)"
Claim construction	Uses generic dictionary definitions	Applies specification definitions and prosecution history
Functional claims	Shows component exists	Shows component exists AND performs claimed function
Verifiability	Assertions without citations	File paths, line numbers, page references, exhibit citations
Speculative language	"Probably," "appears to," "may use"	Definitive: "Source code demonstrates," "Testing confirmed"

What Makes a Weak Claim Chart

Missing or Incomplete Elements

The most fatal flaw: the claim chart doesn't address all claim elements. Either elements are skipped entirely, mentioned but not proven with evidence, or grouped together generically without element-by-element analysis.

Vague or Speculative Language

Language like "likely," "probably," "appears to," or "may use" signals speculation rather than evidence.

"The system probably uses a database" is guessing. "PostgreSQL database connection string in configuration file (config/database.yml, line 8)" is evidence.

Overly Broad Mapping

Mapping general product capabilities to specific claim requirements without showing the connection.

Example: Claim requires "analysing network packets for anomalous traffic patterns using statistical deviation from baseline behaviour metrics." Weak claim chart: "Product monitors network traffic." This shows network monitoring exists but doesn't demonstrate anomaly analysis, statistical deviation calculation, or baseline comparison—the specific requirements.

Technical Misunderstandings

Confusing related but distinct technologies. Asserting that any data processing is "machine learning." Claiming any pattern recognition is "neural networks." These errors suggest the preparer doesn't understand the technology deeply enough to make accurate technical comparisons.

Ignores Prosecution History

If during patent prosecution the applicant distinguished their invention from prior art by stating "our method performs real-time processing, unlike prior art which requires batch processing," and the claim chart then maps this element to a batch processing system, the mapping contradicts the patent's own prosecution history. This creates prosecution history estoppel issues that can doom the infringement argument.

The Doctrine of Equivalents in Claim Charts

Beyond literal infringement, claim charts may also analyse infringement under the doctrine of equivalents.

What Is the Doctrine of Equivalents?

The doctrine of equivalents allows patent holders to prove infringement even when the accused product does not literally satisfy all claim elements, provided the differences are insubstantial. The purpose is to prevent infringers from making only minor, non-substantive changes to avoid literal infringement while still taking the benefit of the invention.

UK and US Approaches

In the UK: Following Actavis v Eli Lilly, the Supreme Court held that even if a variant does not fall within the literal meaning of the claims, it may still infringe if it varies from the invention in a way which is immaterial. The court adopted the "Improver questions" (as reformulated):⁶

1. Does the variant achieve substantially the same result in substantially the same way as the invention?
2. Would it be obvious to the person skilled in the art that the variant achieves substantially the same result in substantially the same way?
3. Would the skilled person understand from the claim language that strict compliance was intended?

If the answers are "yes," "yes," and "no," the variant infringes despite the literal variation.

In the US: The Supreme Court in Graver Tank & Mfg. Co. v. Linde Air Products Co. established the "triple identity test"—an element is equivalent if it performs:²¹

1. Substantially the same function
2. In substantially the same way
3. To obtain the same result

Element-by-Element Application

Critically, Warner-Jenkinson v. Hilton Davis Chemical Co. established that the doctrine of equivalents "must be applied to individual elements of the claim, not to the invention as a whole."³ This means equivalence analysis follows the same element-by-element structure as literal infringement.

For each claim element, you must determine: Is this element literally present in the accused product? If not, is there a substitute element that performs substantially the same function, in substantially the same way, to achieve substantially the same result, with only insubstantial differences?

Doctrine of Equivalents in Claim Charts

When claim charts include equivalents analysis, they show:

• The claimed element and its function/purpose
• The accused product's corresponding component
• Technical analysis of how the substitute performs substantially the same function
• Explanation of why technical differences are insubstantial to a person of ordinary skill in the art

Example

Claimed element: "metallic spring for providing tensile force"

Accused product: Uses a hydraulic cylinder for providing tensile force

Equivalents analysis:

• Function: Providing tensile force (same)
• Way: Hydraulic pressure vs metal elasticity (different mechanism)
• Result: Tensile force applied to component (same)

Whether this qualifies as equivalent depends on whether the differences in "way" (mechanism) are substantial or insubstantial to someone skilled in mechanical engineering. This requires technical expert judgement and understanding of whether practitioners would view these mechanisms as interchangeable for the stated purpose.

Limitations on Doctrine of Equivalents

The doctrine has important limitations. Prosecution history estoppel can prevent reliance on equivalents if the patent applicant narrowed claims during prosecution to distinguish prior art. Additionally, equivalents cannot recapture claim scope that was surrendered during prosecution or that would read on prior art.²²

How to Read and Evaluate a Claim Chart

When you receive a claim chart (in a cease and desist letter, during litigation, or for due diligence), evaluate it systematically:

Claim Chart Evaluation Checklist

Question	What to Look For	Red Flag
1. Are all elements addressed?	Count claim elements vs chart rows. Every limitation should have dedicated evidence.	Missing rows, grouped elements, or generic "satisfies elements 2-4"
2. Is evidence specific and verifiable?	File names, line numbers, page references, exhibit citations, technical specifications	Vague assertions: "likely uses," "appears to," "probably"
3. What's the evidence source?	Source code, technical documentation, test results, teardown analysis	Heavy reliance on marketing materials without technical backup
4. Is the technology correctly described?	Accurate technical characterisation of accused product functionality	Technical errors, confusion between related technologies
5. Does claim construction match intrinsic evidence?	Terms interpreted per specification and prosecution history	Generic dictionary definitions when specification provides specific meanings
6. Are functional claims fully addressed?	Both structure AND function demonstrated	Shows component exists but not that it performs claimed function
7. Which claims are charted?	Independent and commercially important claims addressed	Only narrow dependent claims charted
8. Is equivalents analysis rigorous?	Element-by-element function-way-result analysis	Conclusory statements without technical justification

1. Check Completeness

Count the elements in the patent claim. Count the rows or sections in the claim chart. Do the numbers match? Is every claim element explicitly addressed?

If the claim has ten limitations and the chart only maps eight, the analysis is incomplete. The missing elements might be the ones that defeat the infringement argument.

2. Evaluate Evidence Quality

Is the evidence specific and verifiable?

Strong: "User authentication module (auth/login.js, lines 234-267) implements two-factor authentication using time-based one-time password (TOTP) algorithm, as shown in code excerpt below [code snippet follows]."

Weak: "Product uses two-factor authentication."

The first provides verifiable evidence. The second is assertion.

3. Assess Technical Accuracy

If you understand the technology: Does the claim chart correctly describe how the accused product works? Are there technical errors or mischaracterisations?

If you don't understand the technology: Is the explanation clear? Does it provide enough technical detail to be credible? Or is it vague and conclusory?

4. Look for Gaps

Sometimes claim charts list elements but provide evidence that doesn't actually demonstrate those elements. The structural language is there, but the logical connection between evidence and claim element is missing or weak.

Example: Claim requires "training the model using reinforcement learning with reward signals based on user engagement." Chart provides: "Product uses machine learning model (model.pkl loaded in inference.py)." This shows a model exists but doesn't demonstrate reinforcement learning, reward signals, or user engagement-based training.

5. Consider Whether Key Claims Are Addressed

Patents typically have independent claims (broad) and dependent claims (narrower, adding specific features). Has the chart addressed the most commercially important claims? If only narrow dependent claims show infringement while independent claims don't, the patent's scope is more limited than it might initially appear.

Costs and Practical Realities

UK Cost Estimates

Claim chart preparation costs vary significantly based on technology complexity and scope:

Service	Typical UK Cost Range	Notes
Basic infringement chart (single claim, existing documentation)	£5,000–£15,000	Software with available source code
Comprehensive claim chart (multiple claims, reverse engineering)	£15,000–£40,000	Complex software or hardware requiring testing
Expert witness claim chart (litigation-ready, full analysis)	£25,000–£75,000+	Multiple patents, depositions, trial support
Invalidity/prior art chart	£10,000–£30,000	Depends on prior art volume and complexity

These estimates cover technical expert work. Solicitor and barrister fees for claim construction, litigation strategy, and court appearances are additional.²³

US Cost Estimates

US patent litigation is substantially more expensive:

Service	Typical US Cost Range	Notes
Infringement contentions (claim charts for litigation)	$50,000–$150,000	Required early in federal patent litigation
Technical expert report (including claim charts)	$75,000–$300,000+	Full expert analysis with deposition support
IPR petition claim charts (prior art mapping)	$40,000–$100,000	PTAB proceedings

According to AIPLA surveys, median patent litigation costs through trial exceed $2.5 million for cases with $1–10 million at stake, with expert fees representing a significant portion.²⁴

Factors Affecting Cost

Technology complexity: AI and machine learning patents require more specialised expertise than simpler mechanical patents.

Source code availability: Claims requiring code analysis cost more if reverse engineering is needed versus when source code is available through discovery.

Number of claims: Charting five claims costs more than charting one.

Evidence quality requirements: Litigation-ready charts with full citations and exhibit preparation cost more than preliminary analysis charts.

Jurisdictional requirements: US federal court local rules have specific formatting and disclosure requirements that increase preparation costs.

Timeline Considerations

Phase	Typical Timeline
Initial claim chart (enforcement letter)	2–4 weeks
Litigation infringement contentions	4–8 weeks from case filing
Expert report with claim charts	8–16 weeks (discovery period)
IPR petition claim charts	4–8 weeks

Rushed timelines increase costs and may compromise quality.

Cost-Benefit Analysis

Before investing in claim chart preparation, consider:

For patent holders (enforcement):

• What is the accused product's market value?
• Is licensing revenue realistic given the technology overlap?
• Does the strength of claims justify enforcement costs?

For accused infringers (defence):

• What is the exposure if infringement is found?
• Can a non-infringement position be developed?
• Would invalidity challenges be more cost-effective?

We typically advise conducting a preliminary technical assessment before committing to full claim chart development. This identifies whether claims are likely to map convincingly to the accused product, informing the commercial decision about whether to proceed.

The Technical Expert's Role

Building strong claim charts requires both technical expertise and understanding of patent law.

Domain Knowledge

We need to understand the technology at a deep level. For software patents, that means reading and understanding code architecture, algorithms, and data flows. For AI patents, understanding model architectures, training methodologies, and deployment approaches. For hardware, analysing circuit designs, system components, and functional relationships.

Generic legal analysis can identify what claim elements are. Technical experts understand whether and how the accused product actually implements those elements.

Product Analysis

We test products, review source code, analyse system behaviour, reverse engineer functionality, and examine technical documentation. This isn't about reading marketing materials—it's about understanding how systems truly work.

For software patents with source code access, we review actual implementation code. When source code isn't available, we conduct black-box testing, API analysis, network traffic monitoring, and binary reverse engineering.

Evidence Gathering and Documentation

We find the evidence, document it rigorously, and present it clearly. This means:

• Screenshots with annotations highlighting relevant features
• Code excerpts with file paths, line numbers, and contextual comments
• Test results with complete methodology documentation
• Clear technical explanations linking evidence to claim elements
• References to product specifications, documentation, and publicly available information

Claim Interpretation Support

While patent attorneys lead claim construction arguments, technical experts provide the technical perspective on how claim terms would be understood by a person having ordinary skill in the art. When claim language has specific technical meanings, we help identify those meanings and apply them consistently.

Credibility

Claim charts prepared by technical experts with relevant domain expertise carry more weight in settlement negotiations and litigation. They're less likely to contain technical errors, more likely to withstand scrutiny from opposing experts, and better positioned to support persuasive expert testimony.

When Technical Expertise Is Essential

Complex Technology

When patents cover sophisticated technology—AI and machine learning systems, software architectures, semiconductor designs, telecommunications protocols, biotechnology—technical expert preparation of claim charts becomes essential rather than optional.

We've seen claim charts prepared without adequate technical expertise fail when challenged by opposing experts who actually understand the technology deeply.

Software Patents Requiring Code Analysis

Software patent disputes often turn on what the code actually does, not what product descriptions claim. Understanding whether code implements a claimed algorithm requires the ability to read code, understand software architecture, trace execution flows, and map implementation details to claim language.

High-Stakes Enforcement or Defence

When significant damages are at stake, when business operations are threatened, or when enforcement outcomes affect company strategy, investing in technically rigorous claim chart analysis from the start shapes everything that follows.

Credibility in Settlement or Litigation

If you're asserting patents, the technical strength of your claim chart affects settlement negotiations and litigation prospects. If you're defending, the quality of your non-infringement analysis affects your negotiating position and defence strategy.

In both cases, expert-prepared claim charts signal technical rigour and seriousness.

Common Mistakes in Claim Chart Preparation

Grouping Elements Instead of Addressing Individually

Weak claim charts map multiple elements together: "Product features X, Y, and Z satisfy claim elements 2, 3, and 4." Strong charts address each element separately with distinct evidence.

Using Marketing Materials as Primary Evidence

Marketing materials describe what products do at high level. They often oversimplify or use non-technical language. Relying primarily on marketing without underlying technical evidence creates weak claim charts.

Failing to Account for Claim Construction

Using ordinary meanings for claim terms when the patent specification provides specific definitions. This misinterprets claim scope and leads to incorrect infringement conclusions.

Insufficient Technical Depth

Asserting that features exist without explaining how they work or providing evidence of implementation details. This is particularly problematic for software and AI patents where functional similarity isn't obvious without deep analysis.

Ignoring the Every Element Rule

Assuming that partial overlap or general similarity is enough. It isn't. Every single element must be proven with evidence.

Conclusion: The Foundation of Patent Infringement Analysis

Patent infringement cases stand or fall on claim charts. They're not administrative formalities—they're detailed technical analyses proving or disproving whether accused products contain every element of asserted patent claims.

Strong claim charts map every claim element to specific, verifiable evidence. They're technically accurate, reflect proper claim construction, and are prepared with deep domain expertise. They form the foundation for enforcement letters, licensing negotiations, expert reports, and litigation strategy.

Weak claim charts have missing elements, vague evidence, technical errors, or fail to account for claim construction. They invite challenges, undermine enforcement positions, and waste resources on weak infringement theories.

We've prepared claim charts supporting patent enforcement and defending against infringement allegations across software, AI, hardware, and telecommunications technologies. We understand what makes claim charts technically sound and legally defensible—and we've seen what happens when claim charts lack technical rigour.

If you're facing patent infringement analysis—whether asserting claims or defending against them—getting the technical analysis right from the start determines the strength of your position.

This is general information about claim chart analysis, not legal or technical advice for specific situations. Work with qualified patent counsel and consider engaging technical experts who understand both your technology domain and the evidentiary requirements of patent disputes.

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Sources

Footnotes

1. Patents Act 1977, Section 60(1) — Meaning of infringement under UK law. An invention is infringed by doing certain acts "in relation to the invention" without consent. Available at: https://www.legislation.gov.uk/ukpga/1977/37/section/60 ↩

2. Patents Act 1977, Section 125 — Extent of invention. "An invention for a patent for which an application has been made or for which a patent has been granted shall, unless the context otherwise requires, be taken to be that specified in a claim of the specification of the application or patent." Available at: https://www.legislation.gov.uk/ukpga/1977/37/section/125 ↩

3. Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U.S. 17 (1997) — US Supreme Court decision establishing element-by-element analysis requirement for patent infringement and doctrine of equivalents. "The determination of equivalence should be applied as an objective inquiry on an element-by-element basis." Available at: https://www.law.cornell.edu/supct/html/95-728.ZO.html ↩ ↩² ↩³

4. Ocean Tomo, "The Art of the Claim Chart" — Best practices for claim chart preparation, presentation, and formatting for different audiences. Available at: https://oceantomo.com/insights/the-art-of-the-claim-chart/ ↩ ↩²

5. UK Intellectual Property Office, "Patent Infringement" — Official guidance on what constitutes patent infringement under UK law. Available at: https://www.gov.uk/guidance/patent-infringement ↩

6. Actavis UK Ltd v Eli Lilly and Company 2017 UKSC 48 — UK Supreme Court landmark decision on patent claim interpretation, adopting purposive construction and addressing doctrine of equivalents in UK law. Available at: https://www.supremecourt.uk/cases/docs/uksc-2016-0002-judgment.pdf ↩ ↩² ↩³

7. Patents Act 1977, Sections 70A-70F — Unjustified Threats provisions prohibiting groundless threats of patent infringement proceedings. Available at: https://www.legislation.gov.uk/ukpga/1977/37/section/70A ↩

8. Civil Procedure Rules, Part 35 — Experts and Assessors. Rules governing expert evidence in civil proceedings in England and Wales. Available at: https://www.justice.gov.uk/courts/procedure-rules/civil/rules/part35 ↩

9. U.S. District Court Northern District of California, Patent Local Rules — Requirements for infringement contentions and claim charts in federal patent litigation. Available at: https://cand.uscourts.gov/rules/patent-local-rules ↩ ↩²

10. 37 C.F.R. § 42.104 — Content requirements for IPR petitions, including requirement to identify how each claim element is found in prior art. Available at: https://www.law.cornell.edu/cfr/text/37/42.104 ↩

11. Suiter Swantz, "USPTO Enforces Stricter IPR Petition Requirements: Explicit Mapping of Claim Elements Required" (2025) — Explanation of September 2025 enforcement requiring explicit element-by-element prior art mapping in IPR petitions. Available at: https://suiter.com/uspto-enforces-stricter-ipr-petition-requirements-explicit-mapping-of-claim-elements-required/ ↩

12. European Patent Convention, Article 99 — Opposition procedure at the EPO. Opposition must be filed within nine months of patent grant. Available at: https://www.epo.org/en/legal/epc/2020/a99.html ↩

13. Intellectual Property Enterprise Court Guide — Practice guide for patent and IP proceedings in IPEC, including requirements for statements of case. Available at: https://www.gov.uk/government/publications/intellectual-property-enterprise-court-guide ↩

14. IIPRD, "Claim Chart" — Professional guidance on claim chart methodology emphasising evidence matching and investigatory product analysis. Available at: https://www.iiprd.com/claim-chart/ ↩ ↩²

15. IPEC Streamlined Procedure — Procedures for straightforward patent and IP cases with limited disclosure and evidence requirements. Available at: https://www.gov.uk/guidance/intellectual-property-enterprise-court ↩

16. Lumenci, "How to Create an Effective Patent Claim Chart" (2024) — Best practices for claim chart components including patent claims, accused product features, supporting documentation, and element breakdown. Available at: https://lumenci.com/blogs/create-effective-patent-claim-chart/ ↩

17. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) — US Supreme Court decision establishing reliability standard for expert testimony admissibility. Available at: https://www.law.cornell.edu/supremecourt/text/509/579 ↩

18. The Ikarian Reefer 1993 2 Lloyd's Rep 68 — Leading English case on duties and responsibilities of expert witnesses, establishing standards for expert evidence. Available at Westlaw UK. ↩

19. Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc) — Landmark Federal Circuit decision establishing hierarchy of evidence for claim construction. The specification is "the single best guide to the meaning of a disputed term." Available at: https://casetext.com/case/phillips-v-awh-corp-3 ↩

20. USPTO MPEP § 2173.05(g) — Functional Limitations guidance explaining when claim limitations recite features "by what it does rather than by what it is." Available at: https://www.bitlaw.com/source/mpep/2173-05-g.html ↩

21. Graver Tank & Mfg. Co. v. Linde Air Products Co., 339 U.S. 605 (1950) — Foundational US Supreme Court case establishing the doctrine of equivalents and the "triple identity" test (function-way-result). Available at: https://www.law.cornell.edu/supremecourt/text/339/605 ↩

22. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722 (2002) — US Supreme Court decision on prosecution history estoppel and limitations on doctrine of equivalents. Available at: https://www.law.cornell.edu/supct/html/00-1543.ZO.html ↩

23. UK Intellectual Property Office, "IP litigation costs" — Guidance on costs of IP litigation in UK courts. Available at: https://www.gov.uk/guidance/intellectual-property-litigation-costs ↩

24. AIPLA Report of the Economic Survey (2023) — Industry survey on patent litigation costs in the United States. Available at: https://www.aipla.org/ ↩