In Data Engine Technologies LLC v.  Google LLC, [2021-1050] (August 26, 2021) the Federal Circuit affirmed summary judgment of non-infringement of U.S. Patent Nos. 5,590,259; 5,784,545; and 6,282,551 directed to systems and methods for displaying and navigating three-dimensional electronic spreadsheets.

The preamble of the claims at issue recited: “In an electronic spreadsheet system for storing and manipulating information, a computer-implemented method of representing a three-dimensional spreadsheet on a screen display.”  In defeating a prior 101 challenge, DET argued that the invention solved a problem unique to three-dimensional spreadsheets.  On remand, Google asked the district court for a determination whether the claim preamble was a limitation, and if so, what it meant.  The district court held that the preamble was limiting, and required a mathematical relation among cells on different spreadsheets, whereupon Google moved for summary judgment of non-infringement since its accused product was not a three-dimensional spreadsheet.  The district court granted summary judgment, and DET appealed.

On appeal there was no dispute that Google did not infringe under the district court’s construction of “three-dimensional spreadsheet,” the issue being whether the preamble is in fact limiting and, if so, whether the district court’s construction of three-dimensional spreadsheet was correct.  The Federal Circuit noted that DET’s assertion that the preamble term “three-dimensional spreadsheet” is not limiting effectively seeks to obtain a different claim construction for purposes of infringement than the Federal Circuit applied (at DET’s insistence) in holding the claims eligible under § 101.  Noting that a  claim is not a nose of wax, the Federal Circuit said a patentee relies on language found in the preamble to successfully argue that its claims are directed to eligible subject matter, it cannot later assert that the preamble term has no patentable weight for purposes of showing infringement. Thus the Federal Circuit concluded that the preamble term “three-dimensional spreadsheet” was limiting.

 Turning to the district court’s construction of “three-dimensional spreadsheet,” the parties agreed that a three-dimensional spreadsheet requires cells “arranged in a 3-D grid,” but not on whether it also requires “a mathematical relation among cells on different spreadsheet pages,” as required by the district court’s construction.  The Federal Circuit found that neither the claims themselves nor the prosecution history answered the question of whether a three-dimensional spreadsheet requires a mathematical relation among cells on different spreadsheets.  However, based upon the prosecution history, the Federal Circuit agreed with the district court that the preamble term “three-dimensional spreadsheet” requires a mathematical relation.  During prosecution of the application that led to the ’259 patent, the applicants provided an explicit definition of a “true” three-dimensional spreadsheet and distinguished prior art under this definition.  Giving effect to this express definition in the prosecution history, the Federal Circuit determined that the claims require a three-dimensional spreadsheet that “defines a mathematical relation among cells on the different pages.”  The Federal Circuit rejected DET’s arguments that the statements did not rise to the level or clear and unmistakable disclaimer,  noting that consistent with the public notice function of the prosecution history, the public is entitled to rely on these statements as defining the scope of the claims.

Definitions can be very helpful to the patent applicants in giving concrete meaning to the claims, but they can also be very limiting. It’s not that applicants should not use definitions, but that they should be used cautiously. A definition that seems harmless in one context, can be disasterous in another context.