Prior Art Under 35 U.S.C. 102

An invention must be novel to be entitled to a patent. To be novel, the prior art must not anticipate the claimed invention. Prior art constitutes all information that has been made available to the public in any form before a given date that may be relevant to an invention's novelty. Examples of prior art are patents, publications, presentations, working examples used in commerce and public demonstrations. 35 U.S.C. 102 sets forth the prior art that determines whether the invention described in a patent application is novel. The most frequently cited sections of 35 U.S.C. 102 by the Patent Office are (a), (b), (e) and (g).

35 U.S.C. 102(a) states that a person is entitled to a patent unless "the invention was known or used by others in this country, or patented or described in a printed publication in this or a foreign country, before the invention thereof by the applicant for patent." The date of invention is the effective date in 102(a), meaning that the prior art must be known or published before the date of invention. Although the U.S. Patent Office assumes that the application's filing date is the date of invention, the date may be sworn back by filing an affidavit and an oath or declaration.

35 U.S.C. 102(b) states that a person shall be entitled to a patent unless "the invention was patented or described in a printed publication in this or a foreign country or in public use or on sale in this country, more than one year prior to the date of the application for patent in the United States." The application's filing date is the effective date in 102(b), meaning that any prior art activity must be before this date. 102(b) art may also be based on acts by the inventor(s), and not just by another. An offer for sale of the invention's rights may not be considered an offer for sale of the invention and may therefore not be a bar. However, any offer for sale of the invention itself in the U.S. is a 102(b) bar if the offer occurred more than one year prior to the filing date. Additionally, a bar applies for public use of the invention in the U.S., even if the public use is not visible to the general public. However, if the invention's public use is for the purpose of testing or experimentation, then the statutory bar may not apply.

35 U.S.C. 102(e) bars a patent if the invention was described in a published patent application filed by another in the U.S. before the applicant's date of invention. Although patent applications are published eighteen months after their filing date, the prior art date is the earliest effective U.S. filing date or International filing date once the U.S. or International application has published. Simply put, if B files before A invents, and then A files before B's application is published, then B is still prior art because B's filing date is before A's invention date. Additionally, under this provision, the third party applicant's patent does not need to issue.

35 U.S.C. 102(g) allows the second to invent to become the patentee if the first to invent is not diligent in his or her reduction to practice. For example, if A conceives of the invention before B conceives of the invention, but B reduces the invention to practice before A reduces the invention to practice, then if A was not reasonably diligent in his or her reduction to practice, then B is entitled to the patent even though B was not the first to invent. On the other hand, A is entitled to the patent if he or she is able to prove reasonable diligence from a time before B conceived of the invention up until A was able to reduce the invention to practice.