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 without needing permission from the court, which supports the selected answer. The ex parte reexamination process is designed to allow third parties, including defendants in patent infringement lawsuits, to challenge and request a review of the validity of a patent through the United States Patent and Trademark Office. This mechanism operates independently of ongoing litigation, meaning that the patent owner and the court are not involved in the initial filing process.

The ability to file such a request at any time provides defendants with a strategic advantage, enabling them to address potential weaknesses in the patent claims without waiting for the court's proceedings. The ex parte reexamination process is intended to provide an efficient method for resolving questions about patent validity, irrespective of other legal actions that may be ongoing.

Understanding this process helps clarify the notion of patent validity and provides a legal avenue for parties involved in disputes to challenge the strength of a patent, potentially altering the course of litigation. This aspect of patent law encourages dialogue and resolution without finality while allowing for new information or insights into the patent's validity to be considered.