What constitutes prior art under a 102(a) rejection?

Prior art under a 102(a) rejection includes any evidence that shows an invention was known or used before the effective filing date of a patent application. The key point is that this prior art must be available publicly.

Public knowledge in the U.S. prior to the invention date constitutes a foundational element of what can qualify as prior art. This can include information that existed in the public domain, such as knowledge that was disseminated within a community or through public use, before the date of the inventor’s patent application. The intent of Section 102(a) is to prevent an inventor from claiming a patent on something that was already known to the public, ensuring that the patent system rewards genuine innovation rather than merely documenting what is already in the public sphere.

In contrast, the publication of a patent application, while it can serve as prior art if it precedes the effective filing date of the application in question, is not applicable under a 102(a) rejection unless it is established that the application shows prior art that is defined by public knowledge. The sale of a patented product does not constitute prior art unless it occurs before the effective filing date. Moreover, a patent that is obtained after the invention date cannot serve as prior art against a patent application because