Similar Claim Terms May Have Different Meanings-It All Depends.

The U.S. Court of Appeals for the Federal Circuit reiterated that a claim term should be construed according to its plain language and ordinary meaning and should be limited in scope only if a clear and unmistakable disavowal is manifested by the patent applicant. The result here is that three similar claim terms, "each field," "each of plurality of fields" and "a plurality of different fields," are properly construed to have different meanings. ResQNet.com Inc v. Lansa Inc., Case No. 03-1163 (Fed. Cir. Oct. 16, 2003).

ResQnet sued Lansa for infringement of three ResQnet patents U.S. Pat No. 5,530,961 (the `961 patent), 5,831,608 (the `608 patent) and 6,295,075 (the `075 patent). The specification of the `608 patent a continuation-in-part (CIP) of the `961 patent and the `075 patent each referenced the `961 patent. All three patents were directed to software for analyzing field attributes downloaded from a mainframe computer to a PC for permitting multiple PC users to access one mainframe and display a unique graphical user interface (GVI) for each user.

The district court analyzed claim 1 of the `961 patent that recites, in part, "said ID being generated as a function of the number, location and length of each field" (emphasis supplied) and concluded that claim term "every field" means "all fields." The Federal Circuit, noting that the claim element in question was presented in means-plus-function format, first identified the claimed function and the corresponding structure ("an algorithm that recognizes the screen layout and the fields therein..."). Then, considering the claim language as a whole, the Federal Circuit agreed with the district court "that the claimed algorithm evaluates each (and every) field in the information to be displayed." The Court then noted that "the specification sets forth only one embodiment of the algorithm" and that the description of that algorithm "suggests that characteristics of all, not just some, fields are input ..." and that "the specification [nowhere] suggests otherwise."

However, the Federal Circuit reversed the district court's decision regarding the construction of the term "each of a plurality of fields" as found in claim 1 of the `608 patent, finding that in the context of the `608 patent claim (also a means-plus-function claim element), the subject term only required use "of at least two fields"-not every field. In this regard, the Court noted that the `608 patent was the result of a CIP of the application for the `961 patent and the slightly different algorithm disclosed in the `608 patent could select for analysis "potentially a subset of all fields."

Finally, turning to claim 1 of the`075 patent (not a means-plus-function claim but a pure method claim), the Court invoked the plain meaning rule and construed the term "a plurality of specific screen identifying information" to only require "at least two pieces of information, finding no 'clear and unmistakable'" prosecution history to the contrary.

The content of this article does not constitute legal advice and should not be relied on in that way. Specific advice should be sought about your specific circumstances.

Mr Paul Devinsky

McDermott, Will & Emery

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