Context:
In 2015, Ironburg Inventions Ltd sued Valve Corporation in the United States District Court for the Western District of Washington, alleging that Valve’s video game controller featuring rear buttons infringed several claims of its patent.
In November 2019, the district court granted Ironburg’s motion for estoppel, finding Valve estopped from arguing invalidity on grounds which it had not previously raised in a 2016 petition for inter partes review (IPR) of Ironburg’s patent. A jury subsequently found in Ironburg’s favor, awarding it $4.03 million in damages.
At first appeal (
Ironburg I