Public Use Bar

Under 35 U.S.C. § 102(a)(1) (AIA), a patent is not available for an invention that was 'in public use' before the effective filing date of the claimed invention. The public use bar is one of the statutory prior art categories that can invalidate a patent — along with anticipating publications, patents, and on-sale activity. 'Public use' means the invention was used by persons other than the inventor in a manner not kept secret and not controlled by the inventor. Unlike the on-sale bar (which requires a commercial offer for sale), public use can occur even when no commercial transaction or offer has been made — simply allowing a third party to use the invention publicly can trigger the bar. Under the AIA, the inventor's own public use within 1 year before filing is protected by the § 102(b)(1)(A) grace period — the inventor's disclosures are not prior art against the inventor's own application if they occur within 1 year of the effective filing date.

Egbert v. Lippmann (S.Ct. 1881) is the landmark Supreme Court case on public use. Facts: Samuel Barnes invented an improved corset spring in 1855 and gave two of the springs to a woman friend, who wore them in her corset without publicizing them for over 11 years before Barnes sought a patent. The Supreme Court held: the use was a PUBLIC USE despite the fact that the springs were hidden under the woman's clothing and visible to essentially no one. Why? The inventor had allowed another person to use the invention without restriction, without conditions, and without any attempt to preserve secrecy in the invention itself — the use was 'public' in the sense that it was not under the inventor's control or subject to confidentiality. The key principle from Egbert: public use does NOT require visibility to the general public — it requires that the inventor allowed the invention to be used in a manner not subject to secrecy obligations or inventor control.

Public use under § 102(a)(1) has three primary elements: (1) USE — the invention (or its essential features) is being practiced or operated; (2) BY A PERSON OR PERSONS other than solely the inventor (though in some contexts even purely personal use by the inventor can trigger the bar); (3) WITHOUT SECRECY CONTROLS — the use is not subject to a confidentiality agreement, secrecy obligation, or the inventor's control over the invention's secrecy. WHAT IS AND ISN'T PUBLIC USE: Public use INCLUDES: use of the invention by a third party without confidentiality conditions; use of the invention in a commercial setting, even if not publicly visible; sale or transfer of a product embodying the invention without conditions. Public use EXCLUDES: experimental use under the inventor's supervision and control, with the specific purpose of testing and perfecting the invention (the experimental use exception); use under strict confidentiality obligations where the user cannot disclose; purely private experimentation by the inventor alone.

The experimental use exception to the public use bar allows an inventor to test and refine an invention through uses that would otherwise constitute 'public use,' provided the use is genuinely experimental — aimed at testing and perfecting the invention, not primarily commercial or gratuitous. Factors courts examine (from Elizabeth v. Pavement Co., S.Ct. 1877; Lough v. Brunswick Corp., Fed. Cir. 1996): (1) Whether the inventor maintained control over the invention during the testing period; (2) Whether the inventor received compensation for the test uses; (3) Whether persons tested understood they were participating in a test; (4) Whether the inventor recorded the tests and compiled results; (5) Whether the duration of testing was reasonable for the purpose; (6) Whether there were conditions of secrecy attached. KEY LIMITATION: the experimental use exception requires genuine testing to perfect the PATENTED FEATURES of the invention — testing commercial acceptability or market reception does NOT qualify. Testing a new material for durability = experimental; testing whether customers will pay for the product = commercial, not experimental.

Under the AIA: § 102(a)(1) makes public use before the effective filing date prior art; § 102(b)(1)(A) creates an exception: a DISCLOSURE MADE BY THE INVENTOR (or a joint inventor, or by someone who obtained it from the inventor) is NOT prior art if it was made 1 year or less before the effective filing date. Practical application: (1) If the INVENTOR publicly uses the invention and files within 12 months: the inventor's own use is not prior art under § 102(b)(1)(A) grace period; (2) If a THIRD PARTY (not the inventor and not someone who got it from the inventor) publicly uses the invention: that third-party use is prior art under § 102(a)(1) with no grace period; (3) PRE-AIA: under pre-AIA § 102(b), any public use more than 1 year before the actual filing date was a statutory bar — the 12-month period ran from the actual filing date, not the effective filing date. The AIA's grace period applies to inventor disclosures, not to independent third-party activity.