Federal Circuit: Courts Cannot Change A Patent's Scope Based On References To Family Members

The Federal Circuit has overturned a Southern District of California ruling that invalidated five Finjan, Inc. patents asserted against ESET as indefinite. In a November 1 precedential decision, the appellate court held that District Judge Cathy Ann Bencivengo erred in construing a common claim term to include a limitation present only in certain family members that had been incorporated by reference into the challenged patents. The Federal Circuit explained that while a patent incorporated by reference can provide context when construing shared language, it cannot be used to change the scope of the claimed invention in the "host" patent.

Finjan, which via parent Finjan Holdings, Inc. was acquired by Fortress Investment Group LLC in July 2020, sued ESET in the Northern District of California in July 2016 (3:16-cv-03731); the following January, the court granted the defendant's motion to transfer the case on convenience grounds to the state's Southern District ( 3:17-cv-