There are two types of patent re-examination: an ex parte and an inter partes reexamination. In an ex parte type reexamination, once the request is granted and examination begins, there is no opportunity for the opposing party to comment or otherwise participate in the examination process. In an inter partes reexamination, the opposing party is permitted limited comment through the course of the examination process. ---

While a patent reexamination is conducted quite similar to an initial examination, one major difference is noted: no continuation. Many times throught the course of examination, an applicant finds a good opportunity to continue the case under different cover/argument. In a reexamination proceeding, the case is closed to continuation practice. ---

The Commissioner of Patents has the right to and sometimes does order patent reexamination sua sponte – that is on his own volition.  In response to sufficient public outcry, and in an effort to maintain faith in the patent system, certain patents are ordered for reexamination directly by the Commissioner.  While unusual, the Commissioner has evoked this power in several notable cases including the one characterized as the NTP v. RIM Blackberry contest. ---

Reexamination starts in a relatively quick process – in terms of USPTO time.  Upon filing a request of reexamination, the USPTO must respond within 90 days.  This is a rare occasion where the PTO doesn’t have all the time in the world to take an action.  As a result, one can be assured in a reasonable time - one way or the other whether patent validity will be reconsidered by the patent office.  This can help considerably in planning for a patent infringement contest. ---

The conclusion of a patent reexamination proceeding is a ‘re-examination certificate’. A reexamination certificate actually modifies the original patent and is published in the USPTO Official Gazette 2008 under a document having a number such as: US 6,625,037 C1. ---

Patent reexamination is widely available.  Anyone may request reexamination and it is not necessary to reveal one’s identity when bringing a reexamination request against a competitor’s patents. ---

Roughly 500 ex parte reexaminations are filed per year. This corresponds to about 0.33% of the number of patents issued in a given year. About 60 inter partes reexaminations are filed per year.  About 64% of patents in ex parte challenges survive with some of their claims intact. In 26% of the cases all claims are confirmed. In other words, in only 10% of the cases is a patent completely invalidated in an ex parte challenge. ---

Reexamination is taken up by the Central Reexamination Unit of the PTO. The CRU has 52 highly skilled primary examiners who concentrate solely on reexamination. The goal of the CRU is to close prosecution on all ex-parte reexaminations within two years of filing. ---

A US patent may be subject to reexamination request for all times in which the patent remains in force. In Europe, an ‘opposition’ may only be brought within the first 9 months after the patent issues. ---