The Federal Circuit held that patents incorporated by reference did not invalidate Finjan’s claimed patents

The US Court of Appeals for the Federal Circuit (CAFC) ruled in a precedent-setting decision today that the claim term definition in a patent incorporated by reference among the patents at issue does not dictate the claim definition in the asserted patents. The CAFC thus reverses the district court’s claim construction and vacates and remands the grant of summary judgment of invalidity based on indeterminacy.

Claim construction

The patents at issue are those of Finjan, Inc. its US Patent No. 6,154,844 (the “844 Patent”); 6,804,780 (“780 Patent”); 8,079,086 (“086 Patent”); and 9,189,621 (the “621 Patent). All of them are directed to “Systems and Methods for Detecting Computer Viruses in ‘Downloadables’ via a Security Profile.” Finjan sued ESET, LLC for patent infringement in 2017. Claim Construction ” introduced the definition of the term “downloadable”, which appears in all claims of an asserted patent.

The claimed patents either define “downloadable” as “”an executable application program, which is downloaded from a source computer and run on a destination computer”” or include no definition at all. However, the ‘844 and ‘780 patents are a non-issued patent. , incorporates by reference US Patent No. 6,167,520, which defines “downloadable” as an “applet” and as “a small executable or interpretable application program that is downloaded from a source computer and run on a destination computer.” The remaining asserted patents are incorporated by reference in unasserted US Patent No. 6,480,962, which contains the same definition of “downloadable” as the ‘520 patent and as in the ‘780 patent.

The district court held that because the ‘520 patent was incorporated by reference and included a definition that conflicted with the definition of the claimed patent, the definitions could be reconciled by structuring the word “downloadable” to include the word “small,” which ultimately The plaintiff rendered the claims of the patent, which did not include the word “small,” indefinite and therefore invalid. The district court thus granted summary judgment to ESET in March 2021.

DISTRICT COURT’S ERROR

On appeal, however, the CAFC held that the district court erred in construction by reading the word “small” into the definition of “downloadable.” Although “the definitions of any incorporated patent or reference are a part of the host patent…. Incorporation by reference does not transform an invention of the incorporated patent into an invention of the host patent,” the CAFC explained, citing Modine Mfg. Co. v. US Int’l Trade Com’n. Instead, the disclosure of the host patent merely “provides the context for determining what effect, if any, a patent incorporated by reference will have on the construction of the host patent claim.” The Federal Circuit’s opinion added:

“The district court erred because it viewed different definitions across the patent family as competing and determined that the claimed patents should be limited to the most restrictive definition of the term. We disagree. Here, the claimed patents need not be limited because the two definitions are not competing. Prev. Use of a restrictive term in an application does not reinstate that term in a later patent that purportedly deletes the term, even if the earlier patent is incorporated by reference.”

The ‘520 patent which was incorporated by reference “defines a downloadable as ‘small.’ [because it] Claiming an invention capable of downloading only small executable or interpretable application programs represents a subset of the patent family,” the court explained. The ‘844 and ‘780 patents, in contrast, are not limited to the definition of downloadable by requiring a size. and the ‘086, ‘621 and ‘755 patents, which do not have a clear definition of “downloadable,” as other asserted patents contain examples of downloadables that extend from the unasserted ‘520 patent’s focus on “small” executables. or interpretable application programs such as applets. Thus, the CAFC stated that the proper construction of the term downloadable as used in the ‘844, ‘780, ‘086, ‘621, and ‘755 patents is “an executable or interpretable application program, which is downloaded from a source computer and run on a destination computer.” “

Contrary to the district court’s claim construction, the CAFC did not fully reach a determination of invalidity due to indeterminacy but vacated the grant of summary judgment and remanded to the district court for proceedings consistent with new claim construction.