What is “ex parte reexamination”?

“Ex parte reexamination” is primarily a procedure in patent law that allows for the reexamination of a patent's claims based on a request made by a third party. In this process, the United States Patent and Trademark Office (USPTO) reviews the validity of the patent claims without the involvement of the patent owner during the examination phase. This means once the third party files a request, the patent holder does not engage in the reexamination proceedings, which is distinct from other challenges to a patent's validity that may involve back-and-forth communication between the parties.

This reexamination process is initiated by a third party who believes that prior art—information that may affect the patent’s validity—exists but did not influence the original examination of the patent claims. The aim of ex parte reexamination is to ensure that patents granted remain valid and are based on the most accurate and relevant information.

The other answers refer to different aspects of patent law. While public challenges and claims initiated by a third party suggest alternative processes, they do not accurately describe the nature of ex parte reexamination. The mention of a method for challenging a patent after it has been granted is too broad and does not specify the exclusive nature of the ex parte proceedings