Novelty & Prior Art
Types of Prior Art
What the AIA counts as prior art — and what doesn't defeat your patent.
Quick Answer
Under the AIA, § 102(a)(1) bars patents on anything patented, published, publicly used, on sale, or otherwise publicly available before the filing date — worldwide, no exceptions. § 102(a)(2) adds "secret" prior art: prior-filed applications by others that weren't published yet when you filed. A 1-year grace period protects the inventor's own disclosures.
The Categories
§ 102 Prior Art Under the AIA
§ 102(a)(1) — Absolute Novelty Bar
Patented
The invention was patented anywhere in the world before the effective filing date. Includes U.S. and foreign patents. Publication date (not grant date) typically controls.
Printed publication
Any document publicly accessible to interested persons before the filing date — journals, conference papers, website posts, thesis papers, arXiv preprints. No physical printing required.
In public use
The invention was used publicly (not secretly) by any person before the filing date — demonstration at a trade show, use in a public place, open testing program. Geographic scope is worldwide under the AIA.
On sale
A commercial offer to sell the invention was made before the filing date (Pfaff test: commercial offer + invention ready for patenting). Even a confidential sale counts (Helsinn, S.Ct. 2019).
Otherwise available to the public
Catch-all category added by the AIA — any public disclosure not covered by the explicit categories. Expands prior art to cover internet posts, social media, oral presentations recorded publicly.
§ 102(a)(2) — Secret Prior Art (Prior-Filed Applications)
U.S. patent applications
A U.S. patent application that was effectively filed before the applicant's filing date and describes the claimed invention — even if it wasn't publicly available at the applicant's filing date. Becomes prior art when published.
PCT applications
PCT applications that designate the U.S. and were effectively filed before the applicant's filing date. The PCT application's international filing date controls, provided it publishes in English or is translated.
Common-ownership exception
§ 102(b)(2) exception: subject matter disclosed in a § 102(a)(2) reference is NOT prior art if, at the time of the invention, the reference and the claimed invention were owned by the same person or subject to an obligation to assign to the same person.
AIA vs. Pre-AIA
Key Differences in Prior Art Rules
| Pre-AIA (first to invent) | AIA (first inventor to file) | |
|---|---|---|
| System | First-to-invent (can antedate prior art) | First-inventor-to-file (filing date controls) |
| Geographic scope | Public use/on-sale bar limited to U.S. | Worldwide — no geographic restriction |
| On-sale bar | Commercial sale + ready for patenting (Pfaff) | Same Pfaff test; secret sales still count (Helsinn) |
| Grace period | 1-year grace period for all disclosures (§ 102(b)) | 1-year grace period only for inventor's own disclosures (§ 102(b)(1)(A)) |
| Secret prior art | § 102(e) — U.S. applications by others as of filing date | § 102(a)(2) — same concept, broader scope |
| Interference/derivation | Interference proceedings at USPTO to determine priority | Derivation proceedings — narrower, only for derived inventions |
| Applicability | Claims with effective filing date before March 16, 2013 | Claims with effective filing date on/after March 16, 2013 |
FAQ
What qualifies as prior art under the AIA?
Under the AIA (effective March 16, 2013), 35 U.S.C. § 102 defines prior art in two main categories: § 102(a)(1) covers disclosures that were patented, described in a printed publication, in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. § 102(a)(2) covers prior-filed patent applications by others that describe the claimed invention and are published after the applicant's filing date (so-called 'secret prior art'). There is no geographic limitation under the AIA — a public use in China counts equally with a public use in the U.S.
What is the AIA 'on-sale bar' and when does it apply?
The on-sale bar (§ 102(a)(1)) prevents patenting an invention that was 'on sale' before the effective filing date. Under pre-AIA law, this required a commercial offer for sale + ready for patenting (Pfaff v. Wells Electronics, S.Ct. 1998) and was limited to U.S. sales. The AIA removed the geographic restriction. In Helsinn Healthcare v. Teva (S.Ct. 2019), the Supreme Court held that the AIA did not change the meaning of 'on sale' — a secret commercial sale still triggers the bar, even if the details of the invention are not publicly disclosed in the sales transaction. The AIA grace period (§ 102(b)(1)(A)) excepts the inventor's own disclosures made within 1 year before filing.
What is a 'printed publication' for prior art purposes?
A 'printed publication' means any document that was publicly accessible to those interested in the art before the effective filing date. Physical printing is not required — websites, conference presentations, slide decks uploaded online, preprint servers (arXiv), and thesis papers in library databases all qualify if they were publicly accessible. In In re Klopfenstein (Fed. Cir. 2004), the court held that a PowerPoint poster displayed at a conference for 2.5 days (without copies distributed) qualified as a printed publication because it was accessible to attendees.
What is § 102(a)(2) 'secret prior art'?
§ 102(a)(2) bars a patent claim if the invention was described in a U.S. patent or published application that was effectively filed before the applicant's filing date but published after. This creates 'secret prior art' — a reference that wasn't publicly available when the applicant filed but still counts against the applicant's claims. Example: if Inventor A filed on January 1 and Inventor B filed on January 5 and disclosed A's invention, B's application — when it publishes — is § 102(a)(2) prior art against A's claims, even though it wasn't publicly available when A filed. Exception: the § 102(b)(2) common ownership exception can eliminate this bar for disclosures by the same inventive entity or under joint research agreements.
How does the AIA grace period work?
35 U.S.C. § 102(b)(1) provides a 1-year grace period for the inventor's own disclosures. If the inventor publicly disclosed the invention (by any means) within 1 year before the effective filing date, that disclosure is NOT prior art against the inventor's own claims. Additionally, if a third party publicly disclosed the same subject matter after the inventor's own disclosure, the third party's disclosure is also not prior art (the inventor's earlier disclosure 'seeds' the grace period). CAUTION: the AIA grace period is inventor-centric, not just a temporal exception — a third-party independent disclosure before the inventor's filing but after the filing date is still prior art unless it post-dates the inventor's own public disclosure.
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