Federal Circuit Reverses Infringement Ruling and Damages Award After Finding Asserted Claims Lack Written-Description Support

In Mondis Technology Ltd. v. LG Electronics Inc., Nos. 2023-2117, 2023-2116 (Fed. Cir. Aug. 8, 2025), the Federal Circuit reversed the district court’s infringement ruling and a $14 million damages award, finding Mondis’ asserted patent (U.S. Patent No. 7,475,180) invalid for lack of adequate written description.

The ’180 patent discloses systems for connecting a computer with a display based on the verification of an identification number associated with a display. Following a jury trial, the district court found the patent was not invalid and was willfully infringed by LG. The parties cross appealed.

On appeal, the Federal Circuit found the patent invalid because it lacked written description for identifying a “type” of display. While the specification’s lack of express disclosure was not “automatically” fatal, the Court found that Mondis’ expert testimony and the prosecution history were not substantial evidence to support a finding of validity. The Court explained that the cited expert testimony discussed infringement rather than validity and was silent regarding the “type” limitation. The Court also rejected Mondis’ argument that, because the limitation was added in a claim amendment without examiner objection, the finding of validity was entitled to “an especially weighty presumption of correctness.” Because there was no evidence the examiner considered whether the amendment was adequately supported, the prosecution history did not constitute substantial evidence. The Federal Circuit thus reversed.