Can a person being sued for infringement file a request for an ex parte reexamination without permission from the court?

A person being sued for infringement can indeed file a request for an ex parte reexamination at any time without needing permission from the court. This is significant within the patent process as it allows a party to challenge the patent's validity without the constraints that litigation typically imposes.

The ex parte reexamination procedure, governed by the United States Patent and Trademark Office (USPTO), is designed to allow any third party, including one who is being sued for patent infringement, to seek a review of the patent's claims based on prior art. This process can occur independently of ongoing litigation and is particularly beneficial because it enables a potentially infringing party to contest the validity of a patent while the litigation is still in progress.

This flexibility in the process reflects a respect for the administrative authority of the USPTO in reexamining the validity of patents, reinforcing that the rights to file for reexamination are not curtailed by court procedures or the timing of litigation activities. Thus, the ability to initiate an ex parte reexamination request at any time underscores the independence of the reexamination process from the courts.