Patent Case Summaries November 9, 2022

Patent Case Summaries | Week Ending November 4, 2022

A weekly summary of the precedential patent-related opinions issued by the Court of Appeals for the Federal Circuit and the opinions designated precedential or informative by the Patent Trial and Appeal Board.

Finjan LLC v. ESET, LLC, et al., No. 2021-2093 (Fed. Cir. (S.D. Cal.) Nov. 1, 2022). Opinion by Reyna, joined by Prost and Taranto.

Finjan sued ESET for infringement of four patents related to systems and methods for detecting computer viruses in a “Downloadable” through a security profile. The patents are part of a family of patents that recite differing definitions of the claim term “Downloadable.” Two of the asserted patents defined “Downloadable” to mean “an executable or interpretable application program, which is downloaded from a source computer and run on the destination computer,” without limiting the size of the program. But those patents incorporated by reference other patents in the family that defined “Downloadable” as limited to “small” executable or interpretable application programs. The remaining two asserted patents incorporated both definitions.

The district court viewed the differing definitions as competing and decided that “Downloadable” should be limited to the more restrictive definition requiring “small” programs. The court then granted summary judgment of invalidity on the basis that the word “small” rendered the claims indefinite. Finjan appealed.

The Federal Circuit reversed the district court’s claim construction. The Federal Circuit construed “Downloadable” according to the broader definition, explaining that although “definitions in any incorporated patents or references are part of the host patent … incorporation by reference does not convert the invention of the incorporated patent into the invention of the host patent.” The Federal Circuit stated that “the use of a restrictive term in an earlier [patent] does not reinstate that term in a later patent that purposely deletes the term, even if the earlier patent is incorporated by reference.” 

Applying those principles, the court determined that the asserted patents had expanded on the incorporated patents’ focus on “small” executable or interpretable application programs. For example, the asserted patents provided additional examples that did not involve “small” programs. The Federal Circuit therefore held that the term “Downloadable” in the asserted patents is not limited to “small” executable or interpretable application programs. Accordingly, the Federal Circuit reversed the district court’s claim construction, vacated the summary judgment, and remanded.

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