Plaintiff Collaterally Estopped From Establishing Earlier Invention Date

The court granted defendants' motion for summary judgment that plaintiff was collaterally estopped from claiming an earlier invention date for one of its internet security patents. "Defendants rely on [an earlier] order in [one of plaintiff's other cases] which held that the 'presumptive invention date of the [patent-in-suit] is its filing date,' . . . as Plaintiff had not met its burden to show that the [patent] has a priority date of [13 months earlier]. . . . There is no question that Plaintiff was a party in the previous action, that the issue was actually litigated, and that Plaintiff had a 'full and fair opportunity to litigate.' Plaintiff’s argument that collateral estoppel does not apply because the priority date determination in [prior case] was not essential to the final judgment lacks merit. It is of no consequence that the determination did not affect the jury’s validity finding, given that the determination was made following a bench trial at which the priority date for the [patent] was one of five issues decided."

Finjan, Inc. v. Proofpoint, Inc. et al, 3-13-cv-05808 (CAND April 12, 2016, Order) (Gilliam, J.)