The patent in issue covered cheese-making vats that contain moving “agitator panels.”  Claim 1 of the patent called for each panel to contain “a plurality of sharp cutting edges disposed in a generally common . . . plane . . . .”  It also disclosed drive shafts moving the panels in “counter-rotation,” and mounting the panels on each shaft in opposite orientation. The alleged infringer sought a declaration of invalidity in the district court, while the patentee counterclaimed for infringement. The district court granted the patentee’s summary judgment motion, finding infringement under the doctrine of equivalents. The court also ruled that the alleged infringer and had not proven that the patent was invalid. The alleged infringer appealed.

The Federal Circuit initially found that the district court wrongly denied summary judgment of literal infringement on the claim term “generally common plane,” which the district court found was infringed by the doctrine of equivalents. Instead, the Federal Circuit found the district court improperly concluded that the claims “require that the panels be ‘on the whole flat’” rather than requiring “only that a plurality of cutting edges lie in a generally common plane.”  Based on the latter interpretation, it held that the record supported a finding that the accused products literally infringed the claims by practicing that limitation.

The Federal Circuit affirmed the district court’s ruling that the alleged infringer had not shown the patent to be invalid for obviousness or anticipation. When addressing obviousness, the court noted that the district court did not expressly consider or make findings on the objective considerations of non-obviousness listed in McGinley. These considerations are “part of—not in addition to—the analysis,” and district courts “may prevent remands by making these potentially crucial fact findings.” Still, the court affirmed after a de novo review of the prior art, finding that none of the prior art directly disclosed the claim terms, “let alone any guidance to do so.” Thus, the prior art “hardly present[ed] a clear and convincing case of non-obviousness.” The court also held that the claims were not invalid for anticipation, because “[a]nticipation requires clear and convincing proof” that the exact claim was disclosed in prior art, while only one prior art patent mentioned counter-rotation but not in any detail.

A copy of the opinion can be found here.