Novelty is the requirement that an invention be new. Under 35 U.S.C. § 102, a claim fails for lack of novelty when a single prior art reference already discloses every element of that claim, arranged as the claim arranges them. Lawyers call this anticipation, and the shorthand is that which infringes if later, anticipates if earlier.
The word doing the most work is single. Novelty is an identity test, not a combination test. If your claim has five elements and a prior patent shows four of them while a second patent shows the fifth, neither reference anticipates. That fact pattern is an obviousness problem under § 103, a separate and much softer standard. Novelty is the narrow gate; obviousness is the wide one, and it is where most applications actually die.
Post-AIA § 102(a)(1) sweeps broadly. Prior art is anything that was patented, described in a printed publication, in public use, on sale, or otherwise available to the public before your effective filing date. Section 102(a)(2) adds a second bucket: U.S. patents and published applications that name another inventor and were effectively filed before your date, even though nobody could read them yet on that date.
Three features of this definition catch people off guard.
It is worldwide and language-agnostic. The America Invents Act removed the old geographic limits, so a product sold in Seoul, a talk given in São Paulo, or a doctoral thesis catalogued in a German university library is prior art against a U.S. application. Nobody has to have read it. Public accessibility, not actual readership, is the test.
Obscurity is not a defense. Courts have treated a single thesis indexed and shelved in one library as a printed publication. A poster displayed at a conference for a few days has qualified. If a person of ordinary skill exercising reasonable diligence could have located it, it counts.
Your own work counts against you. The AIA moved the United States to a first-inventor-to-file system for applications with an effective filing date on or after March 16, 2013. Being first to invent no longer rescues you from someone else’s earlier filing, and it does not rescue you from your own earlier disclosure once the grace period runs out.
To anticipate, a reference must do more than gesture at the same idea. It must disclose every claim limitation, and it must disclose them in the same arrangement. A catalog listing a thousand chemical compounds does not necessarily anticipate a claim to one of them if the reference never points to that compound in particular.
Two doctrines soften the rule at the edges. Under inherent anticipation, a reference discloses a feature it never mentions if that feature is necessarily present in what the reference describes. If prior art teaches a process that unavoidably produces your compound as a byproduct, the compound is anticipated even though the earlier author had no idea it was there. Probability is not enough; inherency demands necessity.
The second is enablement of the reference. A prior art document only anticipates if it teaches a skilled person how to make the thing. Science fiction describing a warp drive does not anticipate a warp drive patent, because it does not enable one. Note the asymmetry with the flip side of the rule: a prior patent is presumed enabled for what it claims, and the burden of showing otherwise falls on the applicant.
Section 102(b)(1) creates the exception most inventors rely on. A disclosure made one year or less before your effective filing date does not count as prior art if it came from the inventor, from a joint inventor, or from someone who obtained the subject matter from them. The grace period also shields you from an intervening third-party disclosure of the same subject matter after your own disclosure went public, which gives an early publisher a limited defensive shield.
This is a U.S. rule and only a U.S. rule. The European Patent Convention, China, and most other major systems apply absolute novelty: any public disclosure before the filing date, including the inventor’s own, destroys patentability there with only narrow exceptions for abusive disclosures and certain recognized exhibitions. The practical consequence is unforgiving. Launch the product, publish the paper, or run the Kickstarter, and you may still have twelve months in the United States while your rights in Europe and Asia are already gone. Filing before any disclosure is the only way to keep both options open.
Two categories of prior art come from the inventor’s own commercial conduct rather than from anyone’s publication, and they are the ones that most often surprise a patent owner years later.
Public use means using the invention in public without a limiting obligation of confidentiality. Testing a product on a public road, letting a customer use a prototype without a confidentiality agreement, or wearing a device visibly in a public place can each start the clock, even if no one could see how the invention works internally.
The on-sale bar is triggered when the invention is both the subject of a commercial offer for sale and ready for patenting. That two-part framework comes from Pfaff v. Wells Electronics, 525 U.S. 55 (1998), where the Supreme Court held that an invention need not be built yet to be ready for patenting: drawings detailed enough to enable a skilled person suffice. An accepted purchase order for a product still on the drawing board can therefore be a bar.
Helsinn Healthcare S.A. v. Teva Pharmaceuticals USA, Inc., 586 U.S. 123 (2019), answered the question the AIA reopened. Helsinn had signed distribution and supply agreements for a palonosetron dose more than a year before filing. The agreements were announced, but the dose itself stayed confidential. The Court held unanimously that the sale still triggered the on-sale bar, and that the AIA’s new catchall phrase “otherwise available to the public” did not quietly abolish decades of precedent treating secret commercial sales as invalidating. A confidential supply contract counts.
An examiner searching your application is looking for exactly one document that reads on every element of a claim. If they find it, you get a § 102 rejection and you must either amend the claim to add a limitation the reference lacks, or argue that it does not disclose what the examiner says it does. If they can only assemble the invention from two or more documents, the rejection shifts to § 103, and the fight becomes whether a skilled person would have had a reason to combine them.
Novelty also outlives examination. It is a defense in litigation and the primary ground in inter partes review at the Patent Trial and Appeal Board, where challengers may rely only on patents and printed publications. Prior art the examiner never saw is the reason a granted patent can still fall, which is why the search you do before filing is not a formality. For the mechanics of running one, see the linked guide below.
What is novelty in patent law? Novelty means the invention is new. Under 35 U.S.C. § 102, a claim lacks novelty if a single prior art reference already describes every element of it, arranged as the claim arranges them. That is called anticipation. Novelty is a strict identity test, unlike obviousness under § 103, which lets an examiner combine multiple references.
What counts as prior art? Under post-AIA § 102(a), prior art includes anything patented, described in a printed publication, in public use, on sale, or otherwise available to the public anywhere in the world before your effective filing date. It also includes earlier-filed U.S. applications naming another inventor that later publish or issue. Language, country, and obscurity do not matter: a Japanese thesis on a library shelf can anticipate.
How does the one-year grace period work? Section 102(b)(1) gives a U.S. inventor one year from their own public disclosure to file. The grace period covers disclosures by the inventor, a joint inventor, or someone who got the subject matter from them, and it also disarms a third party’s later disclosure of the same subject matter. It is a U.S. rule. Most other countries apply absolute novelty, so a pre-filing disclosure forfeits foreign rights immediately.
Does a secret sale destroy novelty? Yes. In Helsinn Healthcare v. Teva (2019) the Supreme Court held unanimously that a commercial sale triggers the on-sale bar even when the sale is subject to confidentiality and the invention’s details stay secret. The America Invents Act’s phrase “otherwise available to the public” did not change that longstanding rule. A single confidential supply agreement more than a year before filing can invalidate the patent.
Going further: How to run a patent search before filing .
This page is general legal information, not legal advice, and it does not create an attorney-client relationship.
The Supreme Court's corset case held that use by one person, with no duty of secrecy, is an invalidating public use even when no one can see the invention.
The Federal Circuit held that a single reference cannot anticipate by combining separate embodiments; the elements must appear arranged as in the claim.
The Federal Circuit held that a prior patent on a drug inherently anticipated a later patent on the metabolite the body inevitably produces, even though no one knew the metabolite existed.
The Federal Circuit held that selling a product made by a secret process starts the on-sale clock against a later patent on that process, and the America Invents Act did nothing to change it.
The Federal Circuit held that a slide poster displayed at a scientific meeting can be prior art under §102(b) even though it was never distributed or indexed in any library.
The Supreme Court held that a confidential commercial sale to a third party can place an invention 'on sale' under the AIA, just as it did under the prior statute.
The Supreme Court replaced the Federal Circuit's vague 'substantially complete' standard with a two-part on-sale-bar test that can start the clock before a prototype ever exists.
