35 U.S.C. 102: Novelty, Prior Art and the Grace Period Explained

Sources: 35 U.S.C. § 102 (U.S. Code, 2024 ed.); MPEP § 2150, § 2151.

Under the AIA, prior art is judged against the effective filing date of each claimed invention, not the date of invention. Section 100(i)(1) defines it as the actual filing date of the patent or application containing the claim, or, if the application is entitled to it, the filing date of the earliest application to which it claims a right of priority (§§ 119, 365(a), 365(b), 386(a), 386(b)) or the benefit of an earlier filing date (§§ 120, 121, 365(c), 386(c)). Because the date belongs to the claim, two claims in one application can have different effective filing dates.

Two consequences follow. The date of invention is irrelevant, so an applicant can no longer "swear behind" a reference under 37 C.F.R. § 1.131. And under § 102(d), a U.S. patent document claiming priority to a foreign or international application is prior art as of the earliest such application that describes the subject matter, "regardless of where filed," which ends the old Hilmer doctrine.

Sources: 35 U.S.C. § 100(i); 35 U.S.C. § 102(d); MPEP § 2151; MPEP § 2152.01; MPEP § 2154.01(b).

Section 102(a)(1) covers anything that was public before the effective filing date. The MPEP notes three features that differ from the old law:

• No geographic limit. A public use, sale or other disclosure anywhere in the world can qualify. Pre-AIA law required knowledge, use, public use or sale to be "in this country."
• No "by others" requirement. The prior art need not come from someone else; the inventor’s own earlier disclosures count unless an exception in § 102(b)(1) applies.
• Catch-all category. "Otherwise available to the public" sits alongside patents, printed publications, public use and sales.

Printed publications and patents. To anticipate, a document must disclose every element, explicitly or inherently, "arranged or combined in the same way as in the claim," and enable a skilled person to make the invention without undue experimentation (but not necessarily to use it). The USPTO reads the AIA as leaving this standard unchanged.

Sales, including secret ones. The USPTO treats "on sale" in AIA § 102(a)(1) as having the same meaning as in pre-AIA § 102(b): the invention was the subject of a commercial sale or offer for sale, not primarily for experimental purposes, and was ready for patenting (Pfaff v. Wells Electronics). In Helsinn Healthcare v. Teva Pharmaceuticals (2019), the Supreme Court held that because "Congress did not alter the meaning of ‘on sale’ when it enacted the AIA," "an inventor’s sale of an invention to a third party who is obligated to keep the invention confidential can qualify as prior art under § 102(a)." The MPEP draws the consequence: a sale that does not disclose the invention to the public may still support an anticipation or obviousness rejection.

Sources: 35 U.S.C. § 102(a)(1); MPEP § 2151; MPEP §§ 2152.02(b), (c), (d), (f); Helsinn Healthcare S.A. v. Teva Pharmaceuticals USA, Inc., 586 U.S. 123 (2019).

Section 102(a)(2) reaches documents that were not yet public on your effective filing date but were filed earlier. Three kinds of "U.S. patent documents" qualify if they name another inventor: U.S. patents, U.S. patent application publications, and WIPO publications of PCT applications that designate the United States. A designating PCT publication counts "regardless of the international filing date, whether they are published in English, or whether the PCT international application enters the national stage in the United States."

It is prior art as of its effective filing date for the subject matter relied on (§ 102(d)). If it issued or published before your effective filing date, it is also § 102(a)(1) art, which the common-ownership exception below cannot remove.

Sources: 35 U.S.C. § 102(a)(2), (d); MPEP §§ 2154, 2154.01, 2154.01(a).

The grace period runs back from the earliest priority application. The one year is measured from the earliest U.S. or foreign application to which a proper benefit or priority claim is made, if it supports the claim under § 112(a), and extends to the next business day if it ends on a weekend or federal holiday.

The "intervening disclosure" shield is narrow. Under § 102(b)(1)(B), a third party’s disclosure within the grace period is excepted only if it discloses the same subject matter the inventor had already publicly disclosed. The USPTO applies an identical-subject-matter reading: the exception does not apply "even if the only differences" are "mere insubstantial changes, or only trivial or obvious variations." The inventor’s earlier public disclosure can establish the exception whether or not it was itself within the grace period, but a disclosure made more than a year before filing is prior art in its own right.

Common ownership has no grace-period limit but only reaches (a)(2) art. When § 102(b)(2)(C) applies, the document is not available as prior art under either § 102 or § 103. It does not remove a document that was published or issued before the effective filing date (that is § 102(a)(1) art), and a double patenting rejection may still be made.

Proving an exception. The inventor-disclosure exceptions are invoked with a declaration under 37 C.F.R. § 1.130, either of attribution (the disclosure came from the inventor) or of prior public disclosure (identifying the inventor’s earlier disclosure and its date, with a copy if it was a printed publication).

Sources: 35 U.S.C. § 102(b), (c); MPEP § 2151; MPEP §§ 2153.01, 2153.01(a), 2153.02; MPEP § 2154.02(c); MPEP § 2155 (quoting 37 C.F.R. § 1.130).

A claim rejected under § 102 is "anticipated," which the MPEP equates with "not novel." The test, quoted in MPEP § 2131 from Verdegaal Bros. v. Union Oil (Fed. Cir. 1987), is that "a claim is anticipated only if each and every element as set forth in the claim is found, either expressly or inherently described, in a single prior art reference." The reference must teach every element under the claim’s broadest reasonable interpretation.

• Same detail and arrangement, not the same words. "The identical invention must be shown in as complete detail as is contained in the ... claim," arranged as the claim requires, but this is "not an ipsissimis verbis test."
• One species anticipates a genus. When a claim covers several structures or compositions, generically or as alternatives, it is anticipated if any one of them is in the prior art.
• One reference, with limited help. "Normally, only one reference should be used" in a § 102 rejection. Extra references are proper only to prove the primary reference is enabled, to explain the meaning of a term it uses, or to show that an undisclosed characteristic is inherent (MPEP § 2131.01).

Sources: MPEP § 2131 (including § 2131.01); MPEP § 2152.02(b). Case-law decisions on anticipation are collected on our anticipation topic page; obviousness decisions are on the obviousness topic page.

A reference can anticipate through what it necessarily discloses even if it does not say so. Four rules from MPEP § 2112 govern:

1. Old things stay old. Discovering a previously unappreciated property of a prior art composition, or a scientific explanation for how it works, "does not render the old composition patentably new to the discoverer."
2. No contemporaneous recognition needed. A skilled person need not have recognized the inherent feature at the relevant time; it must only in fact be inherent in the reference.
3. Possible is not enough. "The fact that a certain result or characteristic may occur or be present in the prior art is not sufficient to establish the inherency of that result or characteristic." A reference that discloses a broad genus does not inherently disclose every species within it.
4. The examiner must support it. The examiner "must provide a basis in fact and/or technical reasoning to reasonably support the determination that the allegedly inherent characteristic necessarily flows from the teachings of the applied prior art."

Source: MPEP § 2112.

1. Decide which law applies (MPEP § 2159). Applications filed before March 16, 2013 stay under pre-AIA § 102, even after a later request for continued examination or national-stage entry. An application is under the AIA if it contains or ever contained a claim with an effective filing date on or after that date (or claims the benefit of one that did); one such claim brings every claim under the AIA, even if it is later canceled.
2. Determine each claim’s effective filing date from the application’s priority and benefit claims (MPEP § 2152.01).
3. Identify the prior art category: § 102(a)(1) for anything public before that date, § 102(a)(2) for earlier-filed U.S. patent documents naming another inventor (MPEP §§ 2152, 2154).
4. Compare the reference with the claim under its broadest reasonable interpretation, element by element, expressly or inherently (MPEP §§ 2131, 2112).
5. Consider any exception the record supports, such as a § 1.130 declaration or, for § 102(b)(2)(C), a "clear and conspicuous statement" that the subject matter and the claimed invention were commonly owned or subject to an obligation of assignment to the same person by the effective filing date (MPEP §§ 2153-2155).

In our reading, the responses to a § 102 rejection follow the same steps: a missing or differently arranged element, a non-enabling reference, an earlier supported effective filing date, a § 102(b) exception, or an amendment.

Sources: MPEP § 2159; MPEP § 2152.01; MPEP § 2154; MPEP § 2131; MPEP § 2112; MPEP § 2155.

Patents from applications filed before March 16, 2013 (and later ones that never contained a claim with a later effective filing date) are still judged under the first-to-invent version of § 102. Its main subsections, as quoted in the MPEP:

The key differences: pre-AIA (a) and (e) are keyed to the date of invention; public use and sales count only "in this country"; the § 102(b) grace period runs from the earliest U.S. filing date (directly or through the PCT), not a foreign priority date; and the Hilmer doctrine still limits a U.S. patent’s § 102(e) date to its U.S. filing date.

Sources: MPEP § 2132, § 2133, § 2136, § 2138, § 2150, § 2151, § 2152.01, § 2154.01(b), § 2159.

• Treating the grace period as a filing extension. Section 102(b)(1) excepts only the inventor’s own (or inventor-derived) disclosures and later disclosures of the identical subject matter; an independent third-party disclosure of a variation within the year is still prior art.
• Assuming a confidential sale is safe. After Helsinn, a sale to a buyer bound to secrecy can still put the invention on sale.
• Relying on common ownership against a published document. Section 102(b)(2)(C) removes only § 102(a)(2) art, not documents published before the effective filing date.
• Assuming one date per application. Each claim has its own effective filing date, and one claim dated on or after March 16, 2013 puts the whole application under the AIA.

Sources: 35 U.S.C. § 102; MPEP § 2151, § 2152.02(d), § 2153.02, § 2154.02(c), § 2159.02; Helsinn, 586 U.S. 123. The selection of mistakes is our own. Studying for the registration exam? Novelty is core material in our Patent Bar course, and more on examination is on the patent prosecution hub.