In an inter partes review (IPR) proceeding, the Patent Trial and Appeal Board (PTAB) found claims invalid as obvious over a single prior art reference. The single prior art reference was missing a limitation, and the PTAB found “common sense” supplied the missing limitation. The Federal Circuit reversed the finding that in this case, common sense could not be used to supply the missing limitation.
In applying common sense to an obviousness analysis, the Federal Circuit described three caveats. First, common sense is typically invoked to provide a known motivation to combine, not to supply, a missing claim limitation. Second, when common sense supplies a missing limitation, the limitation is “unusually simple” and “peripheral,” not a limitation which “plays a major role in the subject matter claimed.” Third, references to common sense cannot be a wholesale substitute for reasoned analysis and evidentiary support, especially when dealing with a missing limitation.
In this case, common sense could not be used because the missing limitation played a major role in the invention and there was no reasoned analysis or evidentiary support. The court found that the PTAB had relied on “conclusory statements and unspecific expert testimony,” which is not common sense, for the missing limitation.