Infringement Analysis

Patent infringement analysis follows a mandatory two-step process established by the Federal Circuit: STEP 1 — CLAIM CONSTRUCTION: determine the meaning and scope of each patent claim element; this is a question of LAW (not fact); Markman v. Westview Instruments (S.Ct. 1996): claim construction is for the judge, not the jury; Markman hearings are held before trial specifically for claim construction; PHILLIPS v. AWH (Fed. Cir. 2005 en banc): the landmark claim construction case; hierarchy of evidence: (a) intrinsic evidence governs: the claims themselves; the specification (most important context); the prosecution history (inventor representations to USPTO); (b) extrinsic evidence (dictionaries, expert testimony) can be used to help understand the intrinsic evidence but is less authoritative; CLAIM TERMS ARE GIVEN ORDINARY MEANING in context of the specification and prosecution history; STEP 2 — COMPARE CONSTRUED CLAIMS TO ACCUSED PRODUCT/METHOD: apply the construed claim to the accused device or method; this is a question of FACT (decided by the jury at trial); two theories: (a) literal infringement: each claim element is literally present in the accused product; (b) doctrine of equivalents: substantially similar substitute performs the same function in the same way to achieve the same result; ALL-ELEMENTS RULE: for literal infringement, EVERY element of the claim must be present in the accused product; the absence of even one element = no literal infringement; if the product has ADDITIONAL elements beyond the claim, it still infringes (adding more elements does not avoid infringement); PRODUCT vs. METHOD: product claims: compare claim elements to structural features of the accused product; method claims: compare claim steps to the process used by the defendant.

The doctrine of equivalents (DOE) covers products that are substantially the same as the claimed invention: FUNCTION-WAY-RESULT TEST: an element in the accused product is 'equivalent' to a claim element if it: performs the same FUNCTION; in substantially the same WAY; to achieve substantially the same RESULT; Graver Tank & Mfg. Co. v. Linde Air Products (S.Ct. 1950): the foundational DOE case; Warner-Jenkinson Co. v. Hilton Davis Chemical Co. (S.Ct. 1997): confirmed DOE survives; DOE is applied on an element-by-element basis (not the patent as a whole); PROSECUTION HISTORY ESTOPPEL: if a patent applicant narrowed a claim during prosecution to overcome a rejection, the applicant is 'estopped' from using DOE to recapture the surrendered subject matter; Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. (S.Ct. 2002): any narrowing amendment related to patentability creates a rebuttable presumption of full surrender of the surrendered territory; the surrendered territory is the 'estoppel zone' — safe harbor for design-arounds; DEDICATION-TO-PUBLIC BAR: if subject matter was disclosed in the specification but not claimed, it is dedicated to the public; the patent owner cannot use DOE to recover dedicated subject matter (Johnson & Johnston Associates v. R.E. Service, Fed. Cir. 2002); WILSON SPORTING GOODS LIMITATION: DOE cannot be used to expand claims to cover a prior art product; the 'hypothetical claim' that would literally cover the equivalent product must not cover prior art (Wilson Sporting Goods, Fed. Cir. 1988); REVERSE DOE: an accused infringer may use reverse DOE to argue that even though the accused product literally satisfies the claim language, no infringement because the product is so substantially different that it should not be considered to infringe; rarely successful.

Claim charts are the standard tool for documenting patent infringement analysis: WHAT IS A CLAIM CHART: a claim chart is a tabular document mapping each patent claim element to corresponding structure or steps in the accused product or method; format: two-column table; left column: claim element (often with proposed construction); right column: accused product feature that corresponds to (or does not correspond to) the claim element; PURPOSE OF CLAIM CHARTS: provide a structured, element-by-element comparison; create documentation for litigation or licensing negotiations; required in some jurisdictions as part of infringement contentions (mandatory early disclosure of claim charts); help identify design-around opportunities; INFRINGEMENT CONTENTIONS: in many federal court districts, the patent owner must serve 'infringement contentions' shortly after the complaint; the contentions include: specific claims asserted; specific accused products/methods; claim chart showing each element mapped to the accused product; the level of detail required varies by court; CLAIM CHARTS IN LICENSING: patent owners use claim charts to demonstrate to potential licensees why they are infringing; well-prepared claim charts accelerate settlement by making the mapping clear; non-practicing entities (NPEs) routinely use claim charts as the foundation of licensing demand letters; INVALIDITY CLAIM CHARTS: defendants can prepare invalidity claim charts mapping claim elements to prior art references; used to demonstrate that a claim element is anticipated or that a combination of references renders the claim obvious; served as invalidity contentions; COMMON MISTAKES IN CLAIM CHARTS: mapping to product features generally rather than the specific claim element; ignoring the 'all-elements rule'; failing to address function/purpose elements; using high-level descriptions when the claim element requires specific structure.

Freedom-to-operate (FTO) analysis is infringement analysis done from the perspective of the potential infringer: WHAT IS FTO: an FTO opinion assesses whether a company's product or process infringes any valid patent claims owned by a third party; INFRINGEMENT ANALYSIS vs. FTO: infringement analysis: patent owner's perspective — does the accused product infringe our patent?; FTO analysis: potential infringer's perspective — does our product infringe anyone's patent?; same analytical methodology (claim construction + claim mapping) applied from different perspectives; FTO SCOPE: typically focuses on: unexpired patents and published patent applications; patents in the relevant technology area; patents owned by competitors and patent assertion entities; geographies where the product will be made, used, sold, or imported; FTO FOR DIFFERENT ACTIVITIES: making: the product must be compared to claims in the jurisdiction of manufacture; selling: the product must be compared to claims in jurisdictions where sold; importing: § 271(a) covers importing into the US; § 271(g) covers products made by a patented process; FTO OPINION CHARACTERISTICS: prepared by qualified patent counsel; identifies specific patents and claims of concern; analyzes claim construction and application to the product; assesses validity of blocking patents; recommends: design-arounds; licenses; IPR challenges; WILLFUL INFRINGEMENT PROTECTION: an FTO opinion (when obtained before infringement begins) can be used to show good faith; Halo Electronics v. Pulse Electronics (S.Ct. 2016): willful infringement requires subjective bad faith; an FTO opinion demonstrates lack of subjective bad faith; FTO LIMITATIONS: FTO cannot guarantee non-infringement; newly issued patents change the landscape; unpublished patent applications are invisible until 18-month publication; a 'clear' FTO today may change with new patent issuances.

Patent infringement law distinguishes several types of infringement with different analytical requirements: DIRECT INFRINGEMENT (§ 271(a)): making, using, selling, offering for sale, or importing a patented invention; strict liability: no knowledge of the patent required; whoever makes/uses/sells an infringing product directly infringes; DIVIDED INFRINGEMENT: when no single party performs all steps of a method claim, each party that performs some steps = divided infringement; traditionally, there was no infringement if no single party performed all steps; Akamai Technologies v. Limelight Networks (Fed. Cir. 2015 en banc): divided infringement exists when (a) one party directs or controls the other parties to perform the remaining steps, OR (b) the parties are engaged in a joint enterprise; INDIRECT INFRINGEMENT — INDUCEMENT (§ 271(b)): 'whoever actively induces infringement of a patent shall be liable as an infringer'; requires: (1) underlying direct infringement by a third party; (2) knowledge of the patent; (3) specific intent to cause infringement; Global-Tech Appliances v. SEB S.A. (S.Ct. 2011): willful blindness (deliberate ignorance of a known risk) satisfies the knowledge requirement; CONTRIBUTORY INFRINGEMENT (§ 271(c)): selling or offering to sell a component of a patented product or a material for use in a patented process, where the component: is a material part of the invention; is not a staple article of commerce (has substantial non-infringing uses); is known to be especially made/adapted for use in the infringing product; knowledge of the patent required (unlike direct infringement); DESIGN-AROUND RELEVANCE: once an FTO identifies a potential blocking patent, the design-around must avoid BOTH direct and indirect infringement theories; changing an element in the product may eliminate direct infringement but inducement may remain if the product is designed to cause customers to infringe a method claim.