U.S. patent law
Upon filing, the patent application is assigned to a primary examiner at the PTO, who conducts an examination of the PTO prior-art database as part of determining whether a patent should issue. After the examiner initially reviews the application and the search results, there is an exchange of written correspondence between the patent applicant and the examiner. During this exchange, the examiner will often cite prior-art references in addition to those found and cited in the patent application that limit or preclude patentability of the claimed invention.
The examiner will provide these to the applicant, who may then respond with amendments to the claims, information, or arguments to distinguish the claimed invention from the prior art. The back-and-forth procedure in which the applicant attempts to demonstrate the patentability of the claimed invention is called "prosecuting" a patent application.
If, after the initial examination process has been completed, the examiner determines that any claim of the patent application is unpatentable, the claim is rejected and the applicant is notified of the rejection with an explanation. If the applicant makes a request within six months (or such shorter time period as the examiner may specify, he or she has a right to automatic reconsideration of the rejection of the claims, after which the examiner may make the rejection "final."
An applicant whose claims have been finally rejected may appeal the decision of the primary examiner to the Board of Patent Appeals and Interferences. Each appeal is heard by at least three members of the Board. If an applicant is dissatisfied with the decision in an appeal to the Board, he or she may file an appeal with the Federal Circuit or file a civil action against the Commissioner in the U.S. District Court for the District of Columbia.
Appeals of inter partes interference actions in the PTO to establish the priority of an invention proceed in a similar manner. For the applicant who chooses to appeal to the District Court, a new hearing is conducted. One advantage of such anew hearing is that the applicant may be able to introduce additional evidence into the prosecution record.