than one year before the filing date of the patent application is a conclusion of law based on underlying findings of fact. See Monon Corp. v. Stoughton Trailers, Inc., 239 F.3d 1253, 1257 (Fed.Cir.2001). The date one year prior to the date on which the patent application was filed is known as the “critical date.” See id. To prevail on a claim of invalidity based on the on-sale bar, an accused infringer must demonstrate by clear and convincing evidence that the patented device was both the subject of a commercial offer for sale and ready for patenting before the critical date. See Pfaff v. Wells Elecs., Inc., 525 U.S. 55, 67, 119 S.Ct. 304, 142 L.Ed.2d 261 (1998); Monon Corp., 239 F.3d at 1257. See also Robotic Vision Sys., Inc. v. View Eng’g, Inc., 249 F.3d 1307, 1313 (Fed.Cir.2001) (<HOLDING>). 14. The parties agree that the critical date
holding a determination that an invention was onsale within the meaning of the statute requires that a sale be operable the complete invention claimed be embodied in or obvious from the device offered for sale and the sale or offer be primarily for profit rather than for experimental purposes holding that onsale bar triggered by prior commercial offer for sale and subsequent enabling disclosure that demonstrated invention was ready for patenting prior to critical date holding that a subsequent landowner lacks standing for injuries before his or her ownership because the prior owner was the party who was actually harmed by the prior injury holding that the one challenging the patent must in part show that the subject matter of the sale or offer to sell fully anticipated the claimed invention or would have rendered it obvious by its addition to the prior art holding that an assignment or sale of rights in the invention and potential patent rights is not a sale of the invention within the meaning of section 102b