Tanita Corp. v. Homedics-U.S.A, Inc., No. 08 C 7145, Slip Op. (N.D. Ill. Nov. 4, 2010) (Holderman, C.J.).

Judge Holderman construed the claims of plaintiff’s patent to a scale for measuring a person’s weight with a platform that had a clear outer layer so that instructions or warnings could be placed on the inner layer, but still be read by the user through the transparent outer layer. Of particular note, the Court construed the following terms:

  • "Doughnut-shaped" meant a circular shape with a circular-type enclosed center opening." Plaintiff Tanita’s argument that it could be any shape with a center opening was not supported by the patent or dictionary definitions, which identified doughnuts as ring-like.
  • The claim’s preamble was limiting because it stated the purpose or use of the invention and recited an essential part of its structure, a built-in weight meter.