Federal Circuit Decision Provides a Reminder on the Potential Effects of Incorporation by Reference

By James Harris | November 9, 2022

The Federal Circuit recently reversed a summary judgment ruling that a patentee’s claims were indefinite based on a definition found in another patent that was incorporated by reference.


In Finjan LLC v. Eset, LLC, the claim term at issue was the term “downloadable.”  Finjan’s earliest priority application (the ‘639 application) included a common definition of downloadable as an executable application that can be automatically downloaded from a source computer and run on a destination computer.  Finjan filed three different non-provisional disclosures in this family, and one of the three (the non-asserted ‘520 patent) focused on downloadables as “applets” or “small executable or interpretable application programs.”


Finjan’s patents-in-suit each incorporated by reference both the ‘639 application and the ‘520 patent, but did not explicitly define “downloadable.”  The district court construed the claims, however, using the narrower ‘520 patent definition instead of the broader ‘639 application definition, and then ruled that the claims were indefinite based on the construed word “small.”


The Federal Circuit panel first cited to settled law stating that by incorporating a first patent by reference into a second patent, the entire contents of the first patent’s disclosure become a part of the second.  This would include definitions found in the first patent.  But “the use of a restrictive term in an earlier application does not reinstate that term in a later patent that purposely deletes that term, even if the earlier patent is incorporated by reference.”  The panel accordingly reversed the lower court decision and ruled that “downloadable” for purposes of the claims-in-suit should have no size limitation, and thus the claims were not indefinite.


Inventors and assignees often view incorporation by reference as a tool to “reserve” additional supporting material that can be bodily incorporated into a patent application during prosecution if needed.  This case provides a gentle reminder that incorporated documents are already a part of an application, and that defendants will read them for potentially limiting statements, even though such statements were likely made with little to no thought as to the invention that would be claimed in a later patent.  In this instance, the claims were likely saved by a second referenced disclosure with a broader definition, but had that not existed the patentee could have found itself in a difficult situation.


Incorporation by reference is a valuable tool, but should be used with knowledge of what exactly is being incorporated.  Where a limited portion of a prior document is all that is needed, it may be better to incorporate that “small” section explicitly and forego incorporation altogether.