The full case caption appears at the end of this opinion.
This is a patent infringement case. AFG Industries, Inc. and Asahi Glass Co. (collectively, “AFG”) appeal from the February 25, 2000 order of the United States District Court for the Eastern District of Tennessee granting summary judgment of noninfringement in favor of Cardinal IG Company, Inc. (“Cardinal”). On March 23, 2000, AFG filed a timely notice of appeal to this court. We have exclusive jurisdiction pursuant to 28 U.S.C. � 1295(a)(1). On November 2, 2000, we heard oral arguments in this case. Because we find that the district court erred by adopting a construction of the terms “layer” and “interlayer” that contradicts the manner in which these terms are used in the patent specification, and because the underlying findings of the trial court and the factual record are not sufficiently clear to resolve the infringement issue in light of our revised claim construction, we vacate the court’s grant of summary judgment and remand for further proceedings.
I. BACKGROUND
AFG and Cardinal are competing manufacturers of windows with “low-emissivity” coatings. Low-emissivity coatings generally consist of thin, alternating layers of metals coated onto a glass pane. When properly engineered, the metallic coatings are clear, or may have a desired color. These coatings, while permitting visible light to pass, reflect “radiant heat,” or infrared radiation. Because warm objects in a home, such as lights, emit radiant heat, windows with low-emissivity coatings reflect that heat back into a home and reduce energy costs during the winter. In the summer these coatings help conserve energy by transmitting visible sunlight while blocking unwanted, invisible solar heat that readily passes through uncoated windows.
