Claim Charting

A claim chart is the core analytical document in patent practice: DEFINITION: a claim chart is a two-column document that systematically maps each element (limitation) of a patent claim against corresponding evidence — either product features (for infringement analysis) or prior art disclosures (for invalidity analysis); TWO-COLUMN FORMAT: LEFT COLUMN: the patent claim text, broken into individual elements (limitations), one per row; RIGHT COLUMN: the evidence mapping to each element; evidence may be product documentation, source code, screenshots, prior art text, or figures; PURPOSE: claim charts force structured element-by-element analysis; all elements of a claim must be present for literal infringement (all-elements rule); all elements must be shown in prior art for anticipation (§ 102); claim charts make the analysis visible and auditable; PRIMARY USES: (1) INFRINGEMENT CONTENTIONS: required under Local Patent Rules in most federal courts; plaintiff must serve infringement contentions (typically 14-45 days after scheduling conference) with claim charts identifying exactly how each accused product meets each claim element; (2) IPR PETITIONS (PTAB): 37 C.F.R. § 42.104(b)(4) requires claim charts in IPR petitions mapping each claim element to the prior art relied upon; (3) FTO ANALYSIS: claim charts show whether a product's features meet each element of a potentially blocking patent; (4) LICENSING NEGOTIATIONS: claim charts demonstrate to a potential licensee exactly why their product is covered by the patent; (5) PRE-SUIT INVESTIGATION: Rule 11 requires a reasonable pre-filing investigation; claim charts document this analysis; WORK PRODUCT: claim charts prepared by attorneys for litigation are protected work product; internal claim charts are privileged if prepared by or at the direction of counsel.

Infringement claim charts require systematic analysis before and during construction: STEP 1 — CLAIM CONSTRUCTION: before charting, construe each claim term; apply the Phillips standard (intrinsic-first: claims → specification → prosecution history → extrinsic); record your construction in a separate document; the construction determines what evidence maps to each element; STEP 2 — IDENTIFY THE CLAIM TO CHART: start with the independent claims (they determine infringement; dependent claims add limitations); chart the broadest independent claim first; if literal infringement is unlikely for the broadest claim, consider dependent claims that may match; STEP 3 — PARSE THE CLAIM INTO ELEMENTS: divide the claim into individual limitations (elements); preamble ('A method of...'), transitional phrase ('comprising'), each limitation ('receiving...', 'processing...', 'transmitting...') — each gets its own row; STEP 4 — GATHER PRODUCT EVIDENCE: documentation: product manuals; data sheets; marketing materials; patents filed by the accused infringer on the accused product; technical standards the product implements; source code (if available through discovery or reverse engineering); deposition testimony; expert analysis; reverse engineering reports; STEP 5 — MAP EVIDENCE TO ELEMENTS: for each element, identify SPECIFIC evidence in the product that meets the element under your claim construction; QUOTE THE EVIDENCE: quote specific language from manuals or standards; cite specific source code lines; reference specific figures; LITERAL vs. DOE: for each element, determine if it is literally met (the product literally has the claimed feature) or met under the doctrine of equivalents (function-way-result test); DOE mapping requires explicit analysis; STEP 6 — IDENTIFY GAPS: any element that cannot be mapped = that claim is NOT infringed (all-elements rule); consider dependent claim strategies; consider DOE; COMMON FORMAT: Exhibit A to infringement contentions; numbered rows; patent claim text on left; specific product evidence on right with record citations.

Invalidity claim charts differ depending on the theory and forum: ANTICIPATION (§ 102) CHARTS: a single prior art reference must disclose ALL elements of the claim; the chart maps every claim element to a specific disclosure in the single reference; quote specific text, cite figures by number, cite page/column/line numbers; if even one element cannot be found in the single reference, anticipation fails; OBVIOUSNESS (§ 103) CHARTS: a combination of references is needed; chart each element against the reference that teaches it; include a 'motivation to combine' section explaining why a POSITA would have combined the references; must address secondary considerations (commercial success, long-felt need, failure of others) if the patent owner raises them; IPR-SPECIFIC REQUIREMENTS (37 C.F.R. § 42.104): IPR petitions are limited to § 102 and § 103 grounds based on 'patents or printed publications'; the petition must identify each claim challenged; specify each ground (§ 102(a)(1), § 102(a)(2), § 103); provide a claim chart for each ground; explain how the prior art reads on each claim element; include the declaration of a technical expert (§ 42.65); the chart must be supported by expert testimony — bare attorney argument is insufficient; DISTRICT COURT INVALIDITY CONTENTIONS: must be served pursuant to Local Patent Rules (typically with or shortly after claim construction); disclose all prior art references relied upon; include charts for anticipation + obviousness; must be supplemented if additional prior art found; CLAIM CHART QUALITY CHECKLIST: every element is addressed (no skipped limitations); specific citations (not 'see generally'); consistent with claim construction; expert declaration matches chart analysis; prior art publication date confirmed as prior to patent priority date; for combinations: motivation to combine is explicit; secondary considerations addressed.

Claim chart errors can sink an infringement case or IPR petition: ERROR 1 — INCONSISTENT CLAIM CONSTRUCTION: charting one element with a broad construction and another element with a narrow construction of the same term; FIX: record claim constructions before charting; apply consistently throughout; ERROR 2 — SKIPPING ELEMENTS (ALL-ELEMENTS RULE): mapping most but not all elements; claiming infringement is established when it is not; FIX: every row must be filled; if an element cannot be mapped, either reconsider your construction or acknowledge the limitation; ERROR 3 — VAGUE CITATIONS: 'see generally, product manual'; no specific page/section/figure reference; FIX: cite to specific lines, pages, figures, code line numbers; ERROR 4 — CONFLATING LITERAL AND DOE WITHOUT ANALYSIS: saying an element is met without specifying whether literally or under DOE; if DOE, the function-way-result analysis must be explicit; FIX: add 'Literal: [evidence]' or 'Doctrine of Equivalents: [element performs substantially the same function, in substantially the same way, achieving substantially the same result as the claimed element because...]'; ERROR 5 — ATTORNEY ARGUMENT AS EVIDENCE (IPR): PTAB requires expert testimony supporting claim chart positions; bare attorney argument in the petition is given no weight; FIX: every non-obvious claim chart position must be supported by expert declaration paragraphs that are cross-referenced in the chart; ERROR 6 — IGNORING PROSECUTION HISTORY: mapping elements in a way that contradicts claim amendments or arguments from prosecution; FIX: review prosecution history before charting; PHE (prosecution history estoppel) limits DOE arguments for amended elements (Festo); ERROR 7 — WRONG PRIOR ART DATE: using a reference published after the patent's priority date; FIX: confirm the prior art reference's effective date is before the patent priority date; check whether the reference was published, publicly accessible (for conference papers), or patented before the priority date; ERROR 8 — DEPENDENT CLAIM CONFUSION: charting only independent claims but then asserting infringement of dependent claims without separate analysis; FIX: if asserting dependent claims, add rows for dependent claim limitations.

The same two-column format is used in different proceedings with important distinctions: IPR PETITION CLAIM CHARTS: FORUM: PTAB (administrative); GROUNDS: § 102 and § 103 ONLY; prior art limited to 'patents or printed publications' (§ 311(b)); TIMING: one-shot — the petition must present the strongest case; PTAB does not allow amendment of petition; no second bite at the apple; STANDARD: 'reasonable likelihood that the petitioner would prevail with respect to at least one of the claims challenged' (institution); preponderance of evidence (final written decision); EXPERT SUPPORT: required; expert declaration must accompany petition (37 C.F.R. § 42.65); chart positions must be supported by expert declaration paragraphs; ESTOPPEL: § 315(e)(2): after final written decision, petitioner (and real parties in interest) estopped in district court and ITC from raising any ground petitioner raised or 'reasonably could have raised' — narrowed by Valve Corp. (Fed. Cir. 2021) to grounds actually raised in the petition; DISTRICT COURT INFRINGEMENT CONTENTIONS: FORUM: Article III court; GROUNDS: any; TIMING: initial contentions required by Local Patent Rules; can be amended (with showing of good cause in many districts); STANDARD: preponderance (for plaintiff at trial); EXPERT SUPPORT: expert report required later (after claim construction); initial contentions are attorney-prepared; ESTOPPEL: no statutory estoppel equivalent; but contentions lock positions (amendment requires good cause); KEY DIFFERENCE — AMENDMENT: district court allows amendment (with leave); IPR petition is fixed at filing; ERROR IN IPR CHART: if a critical chart position lacks expert support, PTAB denies institution for that ground — no correction; STRATEGIC IMPLICATION: for IPR, over-invest in chart quality before filing; for district court contentions, get the analysis right early but amendment is possible with good cause.