The Patent Act: structure and key sections

Defines the principal terms used throughout Title 35. Notable are § 100(b) ("process" includes new uses of known processes, machines, manufactures, compositions of matter, or materials), § 100(f) ("inventor"), and § 100(i) ("effective filing date"). After the AIA, the definitions in § 100(i)–(j) underpin the first-inventor-to-file regime: priority is determined by effective filing date, not date of invention. Litigators consult § 100 when statutory language is contested — for example, in disputes over whether a software process falls within "process" under § 100(b) or whether an asserted prior reference predates the "effective filing date" of the challenged claim.

The four statutory categories: process, machine, manufacture, composition of matter. Operates as a threshold gate before novelty and obviousness. Subject to three judicial exceptions — laws of nature, natural phenomena, and abstract ideas — applied through the two-step Alice/Mayo framework. Alice Corp. v. CLS Bank Int'l, 573 U.S. 208 (2014); Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66 (2012). § 101 motions to dismiss and motions for judgment on the pleadings are now common early-stage tools for software and diagnostic-method defendants. Berkheimer v. HP Inc., 881 F.3d 1360 (Fed. Cir. 2018), held that the step-two inquiry can present underlying questions of fact. See § 101 eligibility and Alice v. CLS Bank.

Defines the prior-art universe and the novelty requirement. Pre-AIA § 102 contained subsections (a) through (g), mixing date-based and act-based bars (knowledge or use by others, public use, on sale, derivation). The AIA replaced these with § 102(a)(1) (printed publications, public use, on sale, otherwise available to the public before the effective filing date) and § 102(a)(2) (earlier-filed U.S. applications). § 102(b) provides limited grace-period exceptions for inventor disclosures within one year of filing. In litigation, anticipation requires a single reference disclosing every limitation arranged as in the claim. See anticipation and on-sale bar.

Bars a patent where the differences between the claimed invention and the prior art are such that the invention as a whole would have been obvious to a person of ordinary skill at the time the invention was made (pre-AIA) or as of the effective filing date (AIA). The framework is fixed by Graham v. John Deere Co., 383 U.S. 1 (1966), and recalibrated by KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007). Obviousness is the most heavily litigated invalidity ground, both in district court and at the PTAB. See obviousness and KSR v. Teleflex.

Imposes the disclosure requirements: written description, enablement, and best mode (§ 112(a)); definite claiming (§ 112(b)); independent and dependent claim form (§ 112(c)–(e)); and means-plus-function construction (§ 112(f)). Each subsection generates its own line of caselaw: written description is governed by Ariad Pharmaceuticals, Inc. v. Eli Lilly & Co., 598 F.3d 1336 (Fed. Cir. 2010) (en banc); enablement by the Wands factors and Amgen Inc. v. Sanofi, 598 U.S. 594 (2023); definiteness by Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898 (2014). See written description & enablement and definiteness.

Permits joint inventors to apply jointly even if they did not work physically together or contribute equally. Each joint inventor must contribute to the conception of at least one claim. Errors in inventorship can be corrected under § 256. In litigation, inventorship disputes appear as defenses (improper inventorship rendering a patent invalid under pre-AIA § 102(f) or correctable under § 256) and as affirmative claims to add or remove inventors. Pannu v. Iolab Corp., 155 F.3d 1344 (Fed. Cir. 1998), articulates the contribution standard.

Allows a U.S. application to claim the benefit of an earlier foreign application filed in a Paris Convention country, provided the U.S. application is filed within 12 months. Priority is critical when a § 102 reference falls between the foreign filing and the U.S. filing date. The claim of priority must be supported by the foreign disclosure under § 112(a) for each claim relying on the earlier date.

Permits continuation, divisional, and continuation-in-part applications to claim the filing date of an earlier co-pending U.S. application, provided the earlier application supports the claims under § 112(a). Section 120 disputes commonly determine whether a particular claim term has written-description support in a parent application — and thus whether intervening prior art is § 102 art. Hollmer v. Harari, 681 F.3d 1351 (Fed. Cir. 2012).

Authorizes restriction requirements when independent and distinct inventions are claimed in one application, and shields divisional applications filed in response to such requirements from being used as prior art against the parent (the "safe harbor"). The safe harbor is narrow: it applies only to claims consonant with the line of demarcation drawn by the examiner. Geneva Pharmaceuticals, Inc. v. GlaxoSmithKline PLC, 349 F.3d 1373 (Fed. Cir. 2003).

Generally requires publication of pending applications 18 months after the earliest filing date (§ 122(b)), unless the applicant elects non-publication and forgoes foreign filing. Section 122(b) publications are themselves prior art under § 102(a)(2) as of their effective filing date. Section 122(e), added by the AIA, allows third-party submission of relevant prior art during prosecution.

Permits the patentee to surrender the original patent and obtain a reissue when the patent is wholly or partly inoperative or invalid because of a defective specification or drawing, or because the patentee claimed more or less than it had a right to claim. Broadening reissues must be applied for within two years of the original issue date. The recapture rule prohibits reissue claims that recapture subject matter surrendered during the original prosecution. In re Mostafazadeh, 643 F.3d 1353 (Fed. Cir. 2011).

Provides that surrendered original claims have the same effect as if the original patent had not been granted, but creates intervening rights for parties who began making, using, or selling the invention before the reissue. Absolute intervening rights protect specific products made before reissue; equitable intervening rights, in the court's discretion, can extend to continued or expanded business activities where substantial preparation occurred. The same intervening-rights principles apply to reexamination under § 307 and to AIA proceedings under §§ 318(c) and 328(c).

Authorizes correction of inventorship errors — adding an omitted inventor or removing a misjoined one — provided the error occurred without deceptive intent. The court has parallel authority once the patent issues. Section 256 actions arise both as standalone suits (often by would-be co-inventors) and as defenses in infringement litigation, where an accused infringer may argue that the patent is invalid for failing to name the correct inventors. Trovan, Ltd. v. Sokymat SA, 299 F.3d 1292 (Fed. Cir. 2002).

Provides that patents have the attributes of personal property and that applications, patents, and interests therein are assignable in writing. An assignment is void against a subsequent bona fide purchaser unless recorded with the USPTO within three months. In litigation, § 261 governs whether the plaintiff has the chain of title necessary for standing. Defective recording or ambiguous assignment language can create standing problems that lead to dismissal. Abraxis Bioscience, Inc. v. Navinta LLC, 625 F.3d 1359 (Fed. Cir. 2010); see standing.

Whoever, without authority, makes, uses, offers to sell, or sells any patented invention in the United States, or imports a patented invention into the United States, infringes the patent. Strict liability — knowledge and intent are irrelevant. Section 271(a) is the foundation for every infringement claim and is the predicate for indirect-infringement liability under (b) and (c). See direct infringement and literal infringement.

Whoever actively induces infringement of a patent is liable as an infringer. Requires proof of (1) an underlying act of direct infringement; (2) the inducer's knowledge of the patent; and (3) knowledge that the induced acts constitute infringement. Global-Tech Appliances, Inc. v. SEB S.A., 563 U.S. 754 (2011) (willful blindness suffices); Commil USA, LLC v. Cisco Sys., Inc., 575 U.S. 632 (2015) (good-faith belief of invalidity is no defense). See indirect infringement.

Whoever sells (or offers to sell or imports) a component of a patented combination, or a material or apparatus for use in a patented process, knowing the same to be especially made or adapted for use in an infringement and not a staple article suitable for substantial non-infringing uses, is liable as a contributory infringer. The "no substantial non-infringing use" requirement is the principal battleground in § 271(c) litigation. Aro Mfg. Co. v. Convertible Top Replacement Co., 365 U.S. 336 (1961).

Section 271(e)(1) creates a safe harbor for activities reasonably related to obtaining FDA regulatory approval. Merck KGaA v. Integra Lifesciences I, Ltd., 545 U.S. 193 (2005), construed the safe harbor broadly. Section 271(e)(2) makes filing an Abbreviated New Drug Application with a Paragraph IV certification an act of "artificial" infringement, providing the jurisdictional hook for Hatch-Waxman patent litigation. Section 271(e)(4) prescribes the available remedies (including delay of FDA approval).

Reaches the supply of components from the U.S. for combination abroad in a manner that would infringe if combined in the U.S. The Supreme Court has interpreted § 271(f) narrowly: Microsoft Corp. v. AT&T Corp., 550 U.S. 437 (2007) (master copy of software not a "component"); Life Technologies Corp. v. Promega Corp., 580 U.S. 140 (2017) (a single staple component is not "all or a substantial portion").

Bars importation, sale, offer to sell, or use in the U.S. of a product made abroad by a process patented in the U.S. Liability does not attach if the product is materially changed by subsequent processes or becomes a trivial and nonessential component of another product. Section 271(g) is the principal mechanism for enforcing process patents against foreign manufacturers. Bio-Technology General Corp. v. Genentech, Inc., 80 F.3d 1553 (Fed. Cir. 1996).

Provides a personal defense to a person who, acting in good faith, commercially used the subject matter in the U.S. at least one year before the effective filing date or before any disclosure relied on for the § 102(b) grace period. The defense is not a license; it is personal, non-transferable except as part of an entire enterprise, and limited in scope. Originally enacted for business-method patents and broadened by the AIA to all subject matter. Asserted relatively rarely but valuable when available.

"A patentee shall have remedy by civil action for infringement of his patent." The succinct statutory grant of the right to sue. Combined with 28 U.S.C. § 1338(a), which gives federal district courts exclusive subject-matter jurisdiction over patent claims, § 281 establishes that infringement suits proceed in federal court. The patentee must have all substantial rights to sue alone; otherwise the patent owner must be joined. See standing.

Section 282(a) establishes the presumption of validity: a patent is presumed valid, and the burden of proving invalidity is on the party asserting it. The Supreme Court in Microsoft Corp. v. i4i Ltd. Partnership, 564 U.S. 91 (2011), confirmed that the burden is clear and convincing evidence regardless of whether the prior art was before the examiner. Section 282(b) catalogues the principal defenses: noninfringement, absence of liability, invalidity (including lack of compliance with §§ 101, 102, 103, 112), and unenforceability. Section 282(b)(3)(A) carves out failure to disclose best mode as a defense.

"The several courts having jurisdiction of cases under this title may grant injunctions in accordance with the principles of equity." Until eBay Inc. v. MercExchange, L.L.C., 547 U.S. 388 (2006), the Federal Circuit applied a near-automatic rule favoring permanent injunctions. eBay required the traditional four-factor equitable analysis. Section 283 also supports preliminary injunctions, governed by the four-factor test under Winter v. Natural Resources Defense Council, 555 U.S. 7 (2008). See permanent injunctions and eBay v. MercExchange.

Mandates damages "adequate to compensate for the infringement, but in no event less than a reasonable royalty for the use made of the invention by the infringer, together with interest and costs." Permits the court to increase damages "up to three times" the amount found or assessed. Halo Electronics, Inc. v. Pulse Electronics, Inc., 579 U.S. 93 (2016), governs enhancement. The reasonable-royalty floor and lost-profits supplement form the two principal damages theories. See reasonable royalty and lost profits.

"The court in exceptional cases may award reasonable attorney fees to the prevailing party." After Octane Fitness, LLC v. ICON Health & Fitness, Inc., 572 U.S. 545 (2014), an "exceptional" case is one that stands out from others either with respect to the substantive strength of a party's litigating position or the unreasonable manner in which it was litigated. Highmark Inc. v. Allcare Health Management System, Inc., 572 U.S. 559 (2014), applied abuse-of-discretion review on appeal. See exceptional case and Octane Fitness.

"Except as otherwise provided by law, no recovery shall be had for any infringement committed more than six years prior to the filing of the complaint." Section 286 is a damages-recovery limitation, not a true statute of limitations: it does not bar suit but caps the recoverable period. The Supreme Court in SCA Hygiene Products v. First Quality Baby Products, 580 U.S. 328 (2017), held that laches cannot shorten the § 286 period.

Section 287(a) conditions pre-suit damages on either constructive notice (marking) or actual notice. A patentee that sells or licenses unmarked patented articles cannot recover damages for the period before the infringer received actual notice of the specific infringement. The patentee bears the burden to show compliance once the alleged infringer identifies products that should have been marked. Arctic Cat Inc. v. Bombardier Recreational Products Inc., 950 F.3d 860 (Fed. Cir. 2020). Section 287(c) limits remedies against medical practitioners.

A patentee may maintain an action with respect to any valid claim even if other claims of the patent are invalid, provided the invalid claims have been disclaimed. Section 288 reflects the principle that invalidity of one claim does not invalidate the others; each claim stands or falls independently. Less commonly invoked today since defendants typically attack each claim separately and disclaimers can be filed at any time.

Authorizes the design patentee to recover "total profit" of the infringer on the "article of manufacture" to which the patented design has been applied. The Supreme Court in Samsung Electronics Co. v. Apple Inc., 580 U.S. 53 (2016), held that the "article of manufacture" need not be the entire end product sold to consumers; it may be a component. Section 289 makes design patents an unusually potent damages vehicle in product-design litigation.

Where a patentee shows that a substantial likelihood exists that a product was made by the patented process and that reasonable efforts to determine the actual process used have been unsuccessful, the court may shift the burden to the alleged infringer to prove that its product was not made by the patented process. Operates as a discovery and evidentiary aid in process-patent cases (especially for chemical or biotechnological processes performed abroad).

The failure of an infringer to obtain or to present advice of counsel may not be used to prove that the accused infringer willfully infringed or that it intentionally induced infringement. Enacted by the AIA in response to the prior practice of drawing adverse inferences from the absence of opinions. Section 298 does not bar consideration of opinion evidence the accused infringer chooses to present; it bars only the adverse inference from its absence. Reinforces the privilege analysis around opinion letters.

Restricts joinder of accused infringers in a single patent action: separate defendants may be joined only if (1) any right to relief is asserted against them jointly, severally, or in the alternative with respect to or arising out of the same transaction, occurrence, or series; and (2) questions of fact common to all defendants will arise. Allegations that defendants have all infringed the same patent are not sufficient. Enacted to curb the EDTX practice of suing dozens of unrelated defendants in one case. Drives the modern pattern of parallel co-pending cases.

§ 311 limits IPR to grounds under § 102 or § 103 based on patents and printed publications. § 312 sets the petition requirements. § 313 governs preliminary response. § 314 sets the institution standard (reasonable likelihood that petitioner would prevail as to at least one challenged claim) and renders institution decisions generally non-appealable; Cuozzo Speed Technologies, LLC v. Lee, 579 U.S. 261 (2016); Thryv, Inc. v. Click-To-Call Technologies, LP, 590 U.S. 45 (2020). § 315 governs the relationship to civil actions, including the one-year time bar (§ 315(b)) and the statutory IPR estoppel (§ 315(e)). § 316 sets procedural rules. § 317 addresses settlement. § 318 prescribes the final written decision and intervening rights. § 319 provides for appeal to the Federal Circuit. See IPR and IPR estoppel.

§ 321 makes PGR available within nine months of issuance (or reissue with broadened claims) for AIA-eligible patents and permits any § 282(b)(2)–(3) ground (including § 101 and § 112). § 322 sets petition requirements. § 323 governs preliminary response. § 324 sets the institution threshold ("more likely than not" that at least one claim is unpatentable, or a novel or unsettled legal question). § 325 governs relationship to other proceedings, including PGR estoppel. § 326 sets procedural rules. § 327 addresses settlement. § 328 prescribes the final written decision and intervening rights. § 329 provides for appeal. PGR is broader in scope than IPR but narrower in time-window. See PGR.