A Patent Office examiner’s opinion on a patent’s validity is not “finally determined” and grounds for estoppel under 35 U.S.C. § 315(c) in civil court unless all appeal rights regarding that decision, including in civil court, have been exhausted.

The patentee alleged infringement of a “Low Friction Rotary Knife” patent in the Northern District of Ohio based on a “wear” theory, in which the accused infringer’s blade, once put into use, wears into a shape similar to the patentee’s.  The jury found that the patent was valid but not infringed. 

On cross-appeal, the Federal Circuit held that the district court wrongly interpreted the estoppel provision of 35 U.S.C. § 315 when it excluded obviousness-related evidence based on a contemporaneous finding by a Patent Office examiner that such evidence was insufficient.  Specifically, the Patent Office examiner’s opinion, which the accused infringer had sought inter-partes, did not render the question “finally determined” under § 315(c) because the accused infringer’s appeal of that opinion remained pending.  Therefore, the accused infringer should have been permitted to introduce the evidence related to obviousness at trial, regardless of the Patent Office examiner’s finding.  The Court thus vacated and remanded on the limited issue of whether a new trial was warranted for patent invalidity based on obviousness.  The Court affirmed all other findings, noting in particular the lack of evidence that the accused infringer’s blades “ever … infringe, let alone … always, necessarily, or even usually,” and that the patentee therefore failed to support its “wear” theory of infringement with proof of either intent or absence of a substantial non-infringing use.

A copy of the opinion can be found here.