One of the most common reasons for denying a patent application is that the proposed invention conflicts with prior art in the field. “Prior art” is a legal term that essentially means an invention that already exists. Since a patent can be granted only for an invention that is novel and non-obvious, under Sections 102 and 103 of the Patent Act, part of the application involves establishing that the invention is not already known. It cannot have been previously patented by someone else, put into public use, described in a publication (in most cases), or put on sale before the applicant files for patent protection. The prohibition on prior art applies to prior art patented or merely described anywhere in the world, rather than just patents or publications in the United States.
The USPTO examiner also will need to determine whether someone with ordinary skill in the field of the applicant would find that the invention was obvious. This is especially important when an invention is not entirely new but instead is improving on an existing invention. (Read more here about the non-obviousness requirement.)
Searching for Prior Art
An inventor usually will want to make sure that they meet this requirement, to the best of their knowledge, before making the effort of filing a patent application. This means searching for inventions in their field that could be considered prior art by the USPTO. If you locate an existing invention that seems likely to be considered prior art, you may be able to modify your invention to avoid this barrier. If an existing invention does not seem to be prior art to you, but you are concerned that the USPTO examiner may disagree, you can consult an attorney to find out how to address this problem. You may be able to describe your invention in the application in a way that emphasizes its differences from a certain existing invention. This can be critical because an initial rejection or a protracted dispute with the USPTO can become costly to an inventor or a business.
Google offers a patent search feature that helps inventors search for prior art by keyword and category. The USPTO also offers an online service known as PAIR (Public Patent Application Information Retrieval) that documents patents that are currently in effect, as well as patent applications that have been filed. (Even if a patent has not yet been granted, the first-to-file rule means that a previously filed application will take priority.)
Since this process can be complex, and the stakes are high, you may want to retain an attorney to conduct a more thorough search. An attorney may be especially helpful if your invention is very subtle or technical. You should make sure to consult a lawyer who has accumulated expertise in your industry or field of research so that they can effectively recognize an invention that may be considered prior art. Then, the attorney can discuss the results of their search with you and guide you through crafting your application in a way that sets apart your invention.