Limiting the definition of a claim term based on characterizations of the “invention” have no application where, as here, the other statements and illustrations make it clear that the limitations do not describe the invention as a whole. Nevertheless, it undoubtedly remains the best practice to simply not characterize the “invention” at all. While the patentee here ultimately prevailed and the Federal Circuit reasonably concluded that the specification did not mean to imply that the invention as a whole required the additional limitations, this puts a lot of discretion in the court’s hands and will certainly drag out the time and expense of any enforcement attempt, with no potential gain for the patentee.
Background / Facts: The patent here relates to a read only memory (ROM), and in particular to improvements in the connections between the memory cell blocks that make up the grid in the ROM’s memory cell array. The plain language of the claims recites that the blocks are coupled together by metallization lines, with no mention of the lines connecting to “both ends of each block,” or to any end at all. Nevertheless, the district construed the claims as including this limitation, thereby excluding the particular embodiment that of the accused infringer’s product, because of what it perceived to be limiting statements in the specification characterizing the “invention” as requiring these connections.
Issue(s): Whether the specification’s description at one point that the “invention” has a plurality of contacts “connected to the virtual ground lines and main bit line at each the [sic] end of each block” requires a claim construction in which the lines are connected at both ends of each block.
Holding(s): No. The Federal Circuit acknowledged its decision in C.R. Bard, Inc. v. United States Surgical Corp., 388 F.3d 858 (Fed. Cir. 2004), which explained that “[s]tatements that describe the invention as a whole, rather than statements that describe only preferred embodiments, are more likely to support a limiting definition of a claim term.” However, it cautioned that “this principle has no application where, as here, the other statements and illustrations make it clear that the limitations do not describe the invention as a whole.” The problem with the district court’s analysis, it concluded, was that the statements the district court relied on do not describe the entire invention – they describe only one particular embodiment. As it turns out, the specification and drawings here describe over a dozen improvements to various components of ROM circuitry (e.g., to the oscillators, triggers, sense amplifiers, output inverter stages, etc.) and each of the separate sections describing these unrelated improvements refers to the particular improvement it is describing as “the invention.” Thus, in the context of the application as a whole, the invention is no more limited to the particular embodiment cited by the district court as “the invention” than it is limited to any other embodiment described as “the invention” in the specification.