Examples
Worked examples
- Is an instance
A university technology transfer office licenses an issued patent to a startup. In a later infringement suit the startup's competitor argues the claims are anticipated by a prior conference poster. Because of § 282(a), the competitor — not the patent owner — must prove that anticipation defense by clear and convincing evidence, even though the poster was never before the examiner.
- Is an instance
An accused infringer raises a § 282(b)(3) defense that the patent's specification does not enable a person of ordinary skill to practice the full scope of a claim without undue experimentation, seeking to invalidate the claim for lack of enablement under 35 U.S.C. § 112(a) rather than disputing novelty or obviousness.
Counter-examples
Looks similar, but isn't
- Not an instance
A patent examiner rejecting a pending claim during prosecution for anticipation or obviousness is not applying § 282 — no presumption of validity exists yet because no patent has issued; the examiner applies § 102/§ 103 directly and the applicant carries no heightened evidentiary burden in the way an infringement defendant later would.
- Not an instance
A dispute over inventorship or ownership of a patent (e.g., a Bayh-Dole title-election disagreement between a university and a sponsor) is not a § 282 invalidity defense; inventorship and ownership are governed by separate provisions (35 U.S.C. § 256, and the parties' own assignment agreements) and are not among the § 282(b) defense categories.
Editorial commentary
35 U.S.C. § 282 is the presumption-of-validity and defenses provision of the U.S. Patent Act. It does two things in a single section: it presumes an issued patent valid (placing the burden of proving invalidity on whoever challenges it), and it enumerates the categories of defense a defendant may raise in a patent infringement action, including invalidity for anticipation, obviousness, indefiniteness, and lack of enablement.
For research administrators and technology transfer offices, § 282 matters at the point a licensed or asserted patent is actually litigated — it is the reason an accused infringer cannot simply argue a patent ‘shouldn’t have issued’ on a preponderance of the evidence; the Supreme Court’s decision in Microsoft v. i4i (2011) confirmed that clear and convincing evidence is required, and that this heightened standard applies even to prior art the USPTO examiner never saw. Understanding § 282 alongside the patentability sections it incorporates by reference — § 101 (eligible subject matter), § 102 (novelty), § 103 (non-obviousness), and § 112 (enablement/definiteness) — helps a TTO or licensing office assess how defensible a patent in its portfolio actually is if challenged.
Related terms
Machine-readable encodings
Use in your systems
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"description": "<p><strong>35 U.S.C. § 282</strong> is the U.S. Patent Act provision that (a) presumes an issued patent, and each claim of it independently, to be valid, and places the burden of proving otherwise on the party asserting invalidity, and (b) lists the categories of defenses available to a defendant in a patent infringement action. A fact pattern is governed by § 282 whenever an issued U.S. patent's validity or enforceability is being contested in litigation — as opposed to during examination at the USPTO, where no presumption of validity yet applies because no patent has issued.</p><p>Under § 282(a), the presumption attaches at issuance and survives even when the challenged claim relies on prior art the examiner never considered; it does not evaporate simply because a defendant produces new references. In <a href='https://supreme.justia.com/cases/federal/us/564/91/' target='_blank' rel='noopener'>Microsoft Corp. v. i4i Limited Partnership, 564 U.S. 91 (2011)</a>, the Supreme Court held that § 282's presumption requires invalidity to be proved by <strong>clear and convincing evidence</strong> — a heightened standard above the ordinary civil preponderance-of-the-evidence standard — and that this standard applies uniformly, including to prior art the USPTO never examined.</p><p>§ 282(b) enumerates the defenses a party may raise in a patent action: (1) noninfringement, absence of liability for infringement, or unenforceability; (2) invalidity of the patent or any claim on any ground specified in Part II of the Patent Act as a condition for patentability — in practice this reaches novelty (<a href='/guides/35-usc-102-patent-novelty-invention-disclosure-timing'>35 U.S.C. § 102</a>), obviousness (35 U.S.C. § 103), and subject-matter eligibility (<a href='/guides/35-usc-101-patentable-subject-matter'>35 U.S.C. § 101</a>); (3) invalidity for failure to comply with the specification, enablement, written-description, or definiteness requirements of <a href='/guides/35-usc-112-specification-enablement-requirement'>35 U.S.C. § 112</a>, or of § 251 (reissue); and (4) any other fact or act made a defense by the Patent Act. Indefiniteness under § 112(b) and lack of enablement under § 112(a) are both raised as § 282(b)(3) defenses, distinct from the novelty and obviousness grounds raised under § 282(b)(2).</p>",
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