A Preamble Held Limiting Based on the Patentee’s Arguments in a Prior Appeal and File History

In Data Engine Techs. LLC, v. Google LLC, No. 21-1050 (Fed. Cir. Aug. 26, 2021), the Federal Circuit affirmed a district court’s summary judgment of noninfringement premised on the construction of a term in the preamble.

DET alleged that Google Sheets product infringes certain claims of the “Tab Patents” directed to systems and methods for displaying and navigating 3D electronic spreadsheets. The district court held that the term “three-dimensional spreadsheet” in the preamble is limiting. Based on that construction, Google Sheets was found non-infringing because it does not define cell positions in all three dimensions.

The Federal Circuit affirmed, holding that the preamble was limiting based on the particular importance DET placed on the term in a previous appeal. DET had argued that the claims were patent eligible subject matter directed to an improvement in three-dimensional spreadsheets, placing patentable weight on the preamble term. The Federal Circuit also noted that during prosecution, the applicant defined a true “three-dimensional spreadsheet” as requiring a mathematical relation to overcome a prior art rejection. Because DET did not dispute infringement under the district court’s claim construction, the Federal Circuit affirmed.