Whether a process invention is reduced to practice when all of its elements are successfully performed or must also be determined to work for a further intended purpose

QUESTIONS PRESENTED 35 U.S.C. § 102(b) (2011) bars the patenting of an invention that was “in public use or on sale in this country, more than one year prior to the date of application for patent in the United States.” The statutory bar is triggered by the sale or public use of an invention that is “ready for patenting,” which can be shown by “proof of reduction to practice before the critical date.” Pfaff v. Wells Elecs., Inc., 525 U.S. 55, 67 (1998). “A process is reduced to practice when it is successfully performed.” Corona Cord Tire Co. v. Dovan Chem. Corp., 276 U.S. 358, 383 (1928). In this case, however, a divided panel of the Federal Circuit ruled—as that court has in other cases—that reduction to practice required not just successful performance of the claimed process, but also the patentee’s subjective determination that the process worked for a later-asserted “intended purpose” appearing nowhere in the patent. Additionally, this Court has ruled that a patentee seeking to rely on the exception for “experimental” uses bears the burden of “full, unequivocal, and convincing” proof that the sale or public use was experimental. Smith & Griggs Mfg. Co. v. Sprague, 123 U.S. 249, 264 (1887). But the Federal Circuit has declared this Court’s view not “tenable,” departing from the decisions of other circuits addressing the same issue. TP Labs., Inc., v. Professional Positioners, Inc., 724 F.2d 965, 972 n.3 (Fed. Cir. 1984). The questions presented are: 1. Whether a process invention is reduced to practice, and thus “ready for patenting,” when all of its elements are “successfully performed,” as this Court has held, or whether it must also be determined to @ work for a further “intended purpose” that need not appear in the patent, as the Federal Circuit holds. 2. Whether, after proof that an invention was on sale or in public use more than one year before the patent application, the patentee bears the burden of proving experimental use by evidence that is “full, unequivocal, and convincing,” as this Court and most regional circuits have held, or whether the patentee bears only a burden of production on experimental use and thus can prevail solely on the patentee’s own post hoc testimony, as the Federal Circuit has held. (ii)