A claim that recites a combination of prior art elements may be obvious when the combination merely involves the use of a “known technique” that “has been used to improve one device” to “improve similar devices in the same way.” KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 417 (2007).  In Intel Corp. v. PACT XPP Schweiz AG—an appeal from a PTAB decision that found challenged claims not unpatentable—the Federal Circuit clarified that when two prior art references disclose different techniques to “address the same problem,” replacing the technique in one reference with the “known technique” in the other reference does not have to be an “‘improvement’ in a categorical sense” for there to be a motivation to combine—it is enough for the replacement technique to be a “suitable option” to address the problem.  Case No. 2022-1037 at 12-13 (Fed. Cir. Mar. 13, 2023).

In Intel, the two prior art references at issue both related to multiprocessor systems and “address[ed] the same problem:  maintaining cache coherency.” Id. at 12.  At the PTAB, the patent challenger maintained that a POSITA “would have naturally turned to” the secondary reference’s mechanism for “maintaining cache coherency … to use … in [the primary reference]” because it “address[ed] the same cache-coherency issue that [the primary reference] also sought to address, just through a different mechanism.”  Id.  The PTAB rejected this argument, explaining that “[i]f … [the primary reference] already addresses [the] problem [of cache coherency] through the use of a known technique similar to that of [the secondary reference]’s, [it] fail[ed] to see why one of ordinary skill in the art would regard [the secondary reference]’s technique as an obvious improvement to [the primary reference].”  Id.

On appeal, the Federal Circuit reversed the PTAB’s factual findings and held that it was sufficient for the patent challenger “to show that there was a known problem of cache coherency in the art; that [the secondary reference’s mechanism] helped address that issue, and that combining the teachings of [the primary and secondary references] wasn’t beyond the skill of an ordinary artisan.”  Id. at 13.  That is, the patent challenger “just had to show that [the secondary reference’s mechanism] was a ‘suitable option’ to replace [the primary reference’s mechanism]” when addressing the issue of cache coherency.  Id. (emphasis added).

Intel highlights that there can be a motivation to replace one prior art element with another element that addresses the same problem even if the replacement would not have been “an ‘improvement’ in a categorical sense” over the original design. See id. at 12-13.

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