Legal Definitions - carrying back the date of invention

Definition: Carrying back the date of invention is the process of antedating a prior-art reference in a patent application. This involves removing a publication, a U.S. patent, or a foreign patent cited as prior art against the application by filing an affidavit or declaration establishing the applicant's completion of the invention in this country or another NAFTA or WTO member country before the effective date of the cited reference.

Example: If a patent application cites a prior art reference that was published on January 1, 2020, the applicant can carry back the date of invention by providing evidence that they completed the invention before January 1, 2020. This can be done by filing an affidavit or declaration that proves the completion of the invention in the United States or another NAFTA or WTO member country before the effective date of the cited reference.

This process is only applicable to U.S. patent applications. An issued patent may also antedate a prior-art reference if the conception predates the prior art, and the inventor used due diligence in reducing the concept to practice.