Secret Sale is Prior Art


The US patent code states that a person is entitled to a patent if the invention is novel, non-obvious and has utility. An invention product sale, including a sale made under a confidentiality agreement, can lose patent rights. See article Patent Elements.

35 U.S.C. Section 102(a) “Novelty; Prior Art.” states: 

            “A person shall be entitled to patent unless 

  1. the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention
  2. . . . .”


Does a sale of a device that incorporates the invention wherein the purchaser is required to keep the inventive aspect or component a secret, comprise a placing the invention “on sale” such that the invention is disclosed in the prior art?  If yes, then patent rights are lost.


The Supreme Court clarified today (January 22, 2019) that such a sale does create prior art that can cause forfeiture of patent rights.  The Court stated that the details of the invention need not be publicly disclosed through the sale in order that the sale create prior art.

Inventor Grace Period

Note that sub-section 2 of 35 U.S.C. Section 102(a) does provide a one year grace period for the inventor.  Stated differently, a public disclosure made by the inventorless than 12 months before the inventor’s filingfor an application of patent will not constitute prior art against the inventor.  

The inventor publicly disclosing the invention will bar all others from filing for patent.  The inventor will have 12 months to file his/her own application for patent. 

Today, the Supreme Court clarified that a “secret sale” of an invention is a public disclosure of the invention.  

Copyright David McEwing, 2019