Prior Narrow Definition Does Not (Necessarily) Limit Claim Scope in Family Member

Finjan LLC v. ESET LLC, — F.4th — (Fed. Cir. 2022)

Finjan’s patents claim a system for checking downloadable files for security concerns.  Back in 1996 when Finjan filed its original provisional application, the focus was on applets or other small downloadable programs.  But downloadables today are much bulkier.  Here, the claims require a number of operations on “a downloadable” and the parties have debated throughout the litigation how to construe that term.

The district court’s approach was a bit convoluted.

  • Construction: The district court first narrowly construed the term as limited only to “small downloadables.” Although the asserted patents do not appears to require smallness, the patents do incorporate-by-reference a family member that particularly defines downloadable as “applets” and as “small executable or interpretable application program[s] which [are] downloaded.”
  • Invalidation: Later, the district court reviewed that construction and concluded that the term “small” is a term of degree without any limiting theory and therefor is invalid as indefinite.

On appeal, the Federal Circuit has reversed on the following point of law:

The use of a restrictive term in an earlier application does not reinstate that term in a later patent that purposely deletes the term, even if the earlier patent is incorporated by reference.

Slip Op.  The court further explained that patents within a family can use two different definitions of the same term.  “[T]hese two definitions can exist in harmony within the patent family.”  The court noted that the earlier application with the “small” limitation was focused on downloading small executables while the patents at issue in this case claim an invention with a changed-focus that is “not limited to ‘small’ executable[s].” Here, the court noted that the patentee had also incorporated by reference another prior patent that did not include the small limit.  For the appellate court, all this means that, for the asserted patents the downloadables are not required to be small.

I have included an image of the patent family tree from the patentee’s brief.  You can see that there are several branches.  I believe that it is those branches (rather than a straight-chain of continuations) that helped the court reach its decision that the family-member definitions were not binding.  The court noted some about of difference in the disclosures as well.

Since the “small” definition was eliminated, that also mooted the question of whether “small” is indefinite.


10 thoughts on “Prior Narrow Definition Does Not (Necessarily) Limit Claim Scope in Family Member

  1. 2

    They simply needed to clean up the federal circuit’s botched intepretation of “downloadable”. Here is a court whose legal gymnastics produced a triple Biles level definition relying on incorporation by reference, while also falling over in the middle of a cartwheel by overlooking the indefinite usage of the subjective “small” in the definition.

  2. 1

    This is a reversed summary judgement of claim indefiniteness [a remand, not a trial decision, with, as noted, a much easier standard for reversal, and a single-issue decision]. Is there another issue? This decision notes that “Finjan claims priority for each of the asserted patents [through a convoluted chain] back to provisional application No. 60/030,639(“the ’639 application”), filed November 8, 1996.” However, the decision also notes that the “small” claim term definition was eliminated in the later specifications. How does one get to validly change patent claim term definitions by making specification changes in later applications [that are claiming the same full priority chain benefit] long after those priority benefit applications were filed?

    1. 1.1

      Fair enough question Paul — even as this may be to a different topic of “declaring” a Con versus a CIP.

    2. 1.2

      But to answer your direct question, the article itself hints at answer to your question — incorporation by reference of an earlier patent WITH the alternative arrangement:

      Here, the court noted that the patentee had also incorporated by reference another prior patent that did not include the small limit.

      (also worth noting that there is a CIP in the family line)


          Not to pick a nit, Pro Say, but in this specific case, the CIP need not save the day expressly because one of the earlier cases incorporated by reference provided the flexibility (and a later date was not in fact needed, nor does Paul’s lament come into play).

          This is not to say that Paul’s lament is not a worthy point of discussion — just not for this situation.

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