Under U.S. patent law, an inventor is barred from obtaining a patent on an invention if he or his representatives or assignees files a non-U.S. application on the same invention more than 12 months before his effective U.S. filing date and the non-U.S. patent or inventor's certficate is granted before his effective U.S. filing date [35 U.S.C. 102(d)]. This statutory bar typically occurs when a non-U.S. inventor is tardy in filing a U.S. patent application, but it can happen to any inventor who files a non-U.S. (foreign) application before filing his U.S. application.
The acts (filing the non-U.S. application and issuance of the non-U.S. patentor inventor's certificate) must occur before specific dates. The non-U.S. filing must occur more than 12 months before (1) the earliest effective filing date of a provisional or nonprovisional (regular) U.S. patent application or (2) the filing date of an international (PCT) application that designates the U.S., which can also legally be the "effective U.S. filing date" (35 U.S.C. 363) The second act, issuance (which is not the same as publication) of the non-U.S patent or inventor's certificate, must occur before the U.S. filing date or PCT filing date. As far as application of this rule is concerned, it matters not what the date of invention is or that the inventor(s) can claim priority of invention based on the filing date of another non-U.S. (national or regional) patent application. The non-U.S. application must have been filed by the same inventor(s) (i.e., the same inventive entity) who file the U.S. application or by his/her/their legal representatives or assignees.
Both acts must occur in the sequence indicated. If the non-U.S. patent issues before the filing of the U.S. application but the non-U.S. application is filed less than 12 months before the U.S. filing date or PCT filing date, the bar is not invoked. The non-U.S. patent is "granted" on the date that formal bestowal of patent rights occurs. The courts have interpreted the word "patented" as it is used in 35 U.S.C. 102(b) in the same way they have interpreted that word in 35 U.S.C. 102 (d). In both instances, the invention that is claimed in the U.S. application either was claimed or could have been claimed in the non-U.S. patent. The claims of the non-U.S. patent need not be valid or still in force.