When two patent applications or a patent application and an issued patent have claims with conflicting subject matter, the PTO may issue an Interference to decide which party is the priority party. This process applies only to applications filed prior to the effective date of AIA (March 16, 2013).
The usual way Interference begins is when one party in one application copies the claims of another patent or of a second application to provoke Interference. However, there is a time limit to when the claims can be copied. Specifically, 35 USC 135(b)(1) and (2) only permit such an action in the application within one year from the date the other patent was issued (1) or the other patent application was published (2). However, (2) only applies if the application was filed AFTER the other application.
This point was discussed in the Federal Circuit opinion of Loughlin vs. Ling in July 11, 2012. US Patent No. 7,434,426 to Loughlin was issued on October 14, 2008. The application from which the patent issued was published on November 18, 2004. An application to Ling was filed on February 5, 2007, but it claimed priority to a provisional application filed on January 16, 2004.
On February 21, 2007, Ling (more than one year from publication date of Loughlin) seeking to provoke an interference, copied claims from Loughlin’s pending application. Loughlin attempted to have the interference dismissed because Ling’s application was filed after Loughlin’s publication date, and the interference request was filed more than a year after Loughlin’s publication date. The Board of Patent Appeals and Interferences decided that since Ling’s application claimed priority to a provisional application filed prior to the publication of Loughlin, the bar under 35 USC 135(b)(2) did not apply. The Federal Circuit agreed with this decision.
Claims can be copied from a patent or patent application to provoke interference (1) only within one year of the patent date; or (2) if the EARLIEST EFFECTIVE DOMESTIC PRIORITY DATE of the application is after the publication date of the application, only within one year of the publication date of the application.