Restrictive Definitions Incorporated by Reference Do Not Necessarily Control for Later Patents in the Same Family

Written by: Blake A. Winn & Daniel P. Hughes

FINJAN LLC v. ESET, LLC

Before Reyna, Prost, and Taranto. Appeal from the Southern District of California.

Summary:  Specific definitions provided in an earlier application in a patent family incorporated by reference into a later patent do not restrict the later patent if that patent does not include the definition.

Patent owner Finjan, LLC, sued Eset, LLC for infringement. The district court held a Markman hearing to determine the definition of the term “downloadable” in the asserted patents. In the hearing, the district court relied on a definition of the term from a non-asserted patent in the same family incorporated by reference into the asserted patents. Based on this definition, the court construed the term to mean “a small executable or interpretable application program which is downloaded from a source computer and run on a destination computer.” With the narrow definition in place, Eset moved for summary judgment of invalidity based on indefiniteness. The court granted the motion, finding the asserted patents indefinite based on the word “small.” Finjan appealed. 

On appeal, the Federal Circuit reversed the district court’s claim construction.  The Federal Circuit explained that, though incorporation by reference does include the incorporated patent into the body of the host patent, the disclosure of the host patent controls how the incorporated patents are viewed. Restrictive definitions from incorporated patents do not control if the definitions are removed. Thus, the Federal Circuit reversed the district court’s claim construction, vacated the district court’s grant of summary judgment, and remanded the case for further proceedings.

Editor: Paul Stewart