Pre-AIA 35 U.S.C. 102: Novelty, Statutory Bars, and Prior Art

Pre-AIA 35 U.S.C. § 102 is the version of the federal patent novelty statute that governs any U.S. patent application filed before March 16, 2013, and any patent that issued from one.¹ It does two jobs at once: it defines what counts as prior art measured against the inventor’s date of invention, and it lists several ways an inventor can lose the right to a patent even when the invention is genuinely new. Because these older applications and patents are still tested under these rules in reexamination, validity challenges, and litigation, the pre-AIA framework remains active law.

When Pre-AIA 102 Still Governs

The dividing line is the effective filing date. If the earliest effective filing date of the application is before March 16, 2013, pre-AIA 102 controls. Applications filed on or after that date fall under the AIA version of the statute, which uses a different critical date and eliminates some of the doctrines below. If you are dealing with a patent whose family reaches back to a pre-2013 filing, assume pre-AIA rules apply until you confirm otherwise.

Section 102(a): Prior Public Knowledge and Use

Section 102(a) bars a patent if, before the inventor’s date of invention, the invention was known or used by others in the United States, or patented or described in a printed publication anywhere in the world.²

“Known or used by others” is a term of art. Courts read it to mean knowledge or use that is accessible to the public. If no one deliberately tried to keep the information secret, it qualifies as prior art. A third party’s secret commercial process, by contrast, generally does not count, because it confers no benefit on the public. There is a wrinkle: if the essential features of a secret process are embodied in a product that was then sold publicly, the sale itself can still create a bar.³

“Others” means any inventive entity different from the one named on the application. Even a single-person difference between the two inventive entities is enough for the reference to qualify as “by others.” The critical date under 102(a) is the inventor’s own date of invention, established by proof of conception followed by diligent reduction to practice.

Section 102(b): The One-Year Statutory Bar

Section 102(b) is where inventors most often lose rights they thought they still had. Even if the invention is genuinely novel, four events, if they occur more than one year before the U.S. filing date, permanently bar a patent.⁴ The date exactly one year before filing is the “critical date.” It does not matter whether the inventor or a stranger caused the triggering event.

The four triggers are:

The invention was patented in any foreign country before the critical date.
The invention was described in a printed publication anywhere in the world before the critical date.
The invention was in public use in the United States before the critical date.
The invention was on sale in the United States before the critical date.

The on-sale bar carries a specific test. The Supreme Court held in Pfaff v. Wells Electronics, Inc. that the bar applies when the invention was the subject of a commercial offer for sale and the invention was ready for patenting.⁵ Ready for patenting can be proven either by an actual working embodiment or by drawings and descriptions detailed enough for a skilled person to reproduce the invention. A signed purchase order for a product that exists only on paper can start the clock.

The Experimental Use Exception

Not every pre-critical-date use or sale is fatal. If the primary purpose of the activity was experimentation rather than commercial exploitation, the use does not trigger 102(b). Any commercial benefit has to be incidental to the experimental goal.⁴ Courts evaluate the totality of the circumstances, but two factors carry the most weight: how much control the inventor kept over the testing, and whether the people involved knew the use was experimental. Written experimental-use agreements and contemporaneous records are what typically decide close cases.

Section 102(c): Abandonment of the Invention

Section 102(c) bars a patent when the inventor abandoned the invention itself, which is different from abandoning a patent application. It requires evidence of an intent to give up patent rights, and that intent can be inferred from conduct such as a public declaration that no patent will be sought, or deliberate suppression of the invention. Merely being slow to file, without more, generally does not amount to abandonment under this section.⁶

Section 102(d): The Foreign Patenting Bar

Section 102(d) catches inventors who file abroad first and then wait too long to file in the United States. All four of these conditions must be met for the bar to apply:⁷

The inventor, or their legal representatives or assigns, filed a foreign application more than 12 months before filing in the United States.
The foreign application actually issued as an enforceable patent or inventor’s certificate before the U.S. filing date.
The same applicant or assignee is behind both filings.
The foreign patent covers the same invention.

The foreign patent does not have to be published. It does have to be enforceable. The practical rule: after a foreign filing, you have 12 months to file in the United States, and if the foreign patent has already issued when you miss that window, your U.S. application cannot proceed.

Section 102(e): Prior Art From Earlier Filings

Section 102(e) creates what practitioners call “secret prior art.” Another inventor’s U.S. patent application counts as prior art against you as of its filing date, even though you had no way of knowing about it at the time. The reference qualifies once it eventually publishes or issues as a patent.⁸

A pre-AIA quirk called the Hilmer doctrine limits the effective prior art date of these references to their U.S. filing date, not any earlier foreign priority date the applicant claimed. If a competitor filed first in Japan and then filed in the United States six months later claiming priority, the 102(e) prior art date is the U.S. filing date, not the Japanese one. The AIA eliminated Hilmer going forward, but it still governs pre-AIA applications.⁹

Common Ownership and Joint Research Agreements

When 102(e) prior art is used to support an obviousness rejection under Section 103, pre-AIA 35 U.S.C. 103(c) provides an exception. The prior art cannot be used for obviousness if, at the time the claimed invention was made, both the prior art and the claimed invention were owned by the same person or subject to an obligation of assignment to the same person.¹⁰ Parties operating under a joint research agreement can also invoke this exception, provided the agreement was in effect when the invention was made, the invention arose from work within the agreement’s scope, and the application names the parties to the agreement.

One boundary matters here. This exception applies only to obviousness. It does not defeat a straight novelty rejection under Section 102 itself.

Sections 102(f) and 102(g): Derivation and Priority

Pre-AIA law was a first-to-invent system, and these two subsections are where that principle operates. Section 102(f) bars a patent when the named applicant did not actually invent the claimed subject matter. It typically applies when someone learns an inventive concept from another person and then files a patent claiming it as their own. The Patent Office presumes the named applicants are the true inventors unless evidence indicates otherwise.¹¹

Section 102(g) resolves priority disputes between independent inventors who each claim the same invention. Under pre-AIA law, these were decided in interference proceedings. The statute directs the decision-maker to consider the dates of conception and reduction to practice, and also the reasonable diligence of an inventor who conceived first but reduced to practice last.¹² If you conceived first but a competitor built a working version before you did, you can still win priority by showing you worked diligently and continuously from a point just before the competitor’s conception through your own reduction to practice.

Reduction to practice can be actual, meaning a working embodiment was built and tested, or constructive, meaning a complete patent application fully describing the invention was filed. Either counts. A prior inventor who abandoned, suppressed, or concealed the invention forfeits priority under 102(g), even if they were technically first.²

Swearing Behind a Prior Art Reference

Because pre-AIA law cares about the date of invention rather than the filing date, an applicant hit with a prior art rejection can sometimes escape by proving prior invention. This is done through an affidavit or declaration under 37 C.F.R. 1.131(a), commonly called a Rule 131 declaration.¹³

The declaration must show that the inventor conceived and diligently reduced the invention to practice before the reference’s effective date. Activity in the United States counts. So does activity in a NAFTA country from December 8, 1993 onward, or in a WTO member country from January 1, 1996 onward. This tool has limits: it cannot be used to overcome a reference that claims interfering subject matter, because that dispute belongs in the interference process.

1
United States Patent and Trademark Office. Manual of Patent Examining Procedure Section 2159
2
BitLaw. 35 USC 102 (Pre-AIA) Conditions for Patentability Novelty and Loss of Right to Patent
3
BitLaw. MPEP 2132 – Pre-AIA 35 USC 102(a)
4
United States Patent and Trademark Office. Manual of Patent Examining Procedure – Pre-AIA 35 USC 102(b)
5
Justia. Pfaff v. Wells Electronics, Inc.
6
United States Patent and Trademark Office. Manual of Patent Examining Procedure 2134 – Pre-AIA 35 USC 102(c)
7
United States Patent and Trademark Office. Manual of Patent Examining Procedure Section 2135 – Pre-AIA 35 USC 102(d)
8
United States Patent and Trademark Office. Manual of Patent Examining Procedure 2136 – Pre-AIA 35 USC 102(e)
9
BitLaw. MPEP 2154.01(b) – Determining When Subject Matter Was Effectively Filed Under AIA 35 USC 102(d)
10
U.S. Patent and Trademark Office. Manual of Patent Examining Procedure Section 2146
11
United States Patent and Trademark Office. Manual of Patent Examining Procedure – 2137 Pre-AIA 35 USC 102(f)
12
United States Patent and Trademark Office. Manual of Patent Examining Procedure – 2138 Pre-AIA 35 USC 102(g)
13
United States Patent and Trademark Office. Manual of Patent Examining Procedure – Swearing Behind a Reference Affidavit or Declaration Under 37 CFR 1.131(a)