Patent Prior Art

In order for the U.S. government to issue a patent, the item being patented must be "novel, useful, and not obvious to one skilled in the art."

Prior art refers to all information that was publicly available before a certain date. In the context of patent searches, prior art is information that was available before the invention date (in the U.S.) or the filing date (European and many other countries.) If certain prior art exists, a patent cannot be granted.

For example:

  • "If the invention has been described in a printed publication anywhere in the world, or if it has been in public use or on sale in this country before the date that the applicant made his/her invention, a patent cannot be obtained.

  • If the invention has been described in a printed publication anywhere, or has been in public use or on sale in this country more than one year before the date on which an application for patent is filed in this country, a patent cannot be obtained. In this connection it is immaterial when the invention was made, or whether the printed publication or public use was by the inventor himself/herself or by someone else.

  • If the inventor describes the invention in a printed publication or uses the invention publicly, or places it on sale, he/she must apply for a patent before one year has gone by, otherwise any right to a patent will be lost. The inventor must file on the date of public use or disclosure, however, in order to preserve patent rights in many foreign countries." (excerpted from 35 U.S.C. 102)

More Patent Prior Art Resources

The video below provides a good overview of patent prior art searching. Although it advertises a commercial intellectual property firm, the video is useful to anyone wanting to know more about the prior art patent search process.


Patent Process: What Is a Prior Art Patent Search?

To find additional information on patent prior art, search on Google, using quotes to make the search more specific:

for example:

"prior art"

"what is prior art?"

"prior art databases"

"patents" "prior art"

"prior art databases"

"prior art searches"

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For more information see:

Patent Law in a Nutshell, 2d (West Nutshell)


Patent Law, Fourth Edition (Aspen Treatise)

Patent Law, 4th Edition (Aspen Student Treatise Series) (Aspen Treatise) Kindle Edition

See the article "Considering What Constitutes Prior Art in the United States," for a more detailed explanation of prior art from a legal point-of-view.

See also "When is Something Prior Art Against a Patent?"

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