Background
Ironburg Inventions Ltd. sued Valve Corporation for infringing U.S. Patent Number eight million six hundred forty-one thousand five hundred twenty-five, which covers a video game controller with back controls. Valve filed an inter partes review petition in two thousand sixteen and later amended its invalidity contentions in district court to include grounds raised by a third party. The district court granted Ironburg’s motion for estoppel, preventing Valve from asserting those grounds at trial. A jury found Valve liable for willful infringement and awarded over four million dollars. The Federal Circuit previously vacated and remanded the estoppel ruling, clarifying the burden of proof and the skilled searcher standard.
The court’s reasoning
The Federal Circuit held that the district court erred in finding the prior art references reasonably discoverable. Regarding the Landon IP search evidence, the court found that a classification search returning twenty-six thousand three hundred thirty-three results was insufficient to prove discovery without further narrowing techniques like keyword searches. Regarding the Cardinal IP evidence, the court found the searches tainted by hindsight bias because they utilized forward citation searches and were motivated by the need to locate specific references after the fact. The court concluded that the district court failed to adequately account for these deficiencies in applying the skilled searcher standard.
What it means going forward
Valve is no longer estopped from asserting invalidity grounds based on the Kotkin reference and the Willner-Koji-Raymond combination. The case is remanded for the district court to consider these invalidity grounds in light of the Federal Circuit’s opinion.