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Chicago IP Litigation Tracking Northern District of Illinois IP Cases

Intrinsic Evidence Overcomes Patent Doctrine of Claim Differentiation

Posted in Claim Construction

Kathrein-Werke KG v. Radiacion y Microondas S.A., No. 07 C 2921, Slip Op. (N.D. Ill. May 17, 2010) (Guzmán, J.).

Judge Guzmán construed the contested terms of plaintiff’s patent to a high frequency phase shifter unit having a pivotable tapping element. Of particular note, the Court construed:

  • "Stripline" was a conductive strip, but it did not need to be a flat, conductive strip. Nothing in the claim or specification required striplines be flat, and plaintiff’s extrinsic evidence could not overcome the intrinsic evidence.
  • "Stripline sections", "stripline segments" and "stripline elements" were construed to mean the same thing. While claim differentiation creates a presumption that different terms have different meanings, that presumption was overcome by the intrinsic evidence which showed patentee "obstinately" using the terms to mean the same thing.
  • "Extending" was given its ordinary meaning of "lengthening." The Court held that plaintiff’s definition "lengthening in one or more direction" included an unnecessary element that was not supported by the intrinsic evidence.
  • "Transformers" were defined as "devices that transfer electrical signals and match impedance values." The Court also construed the statement that transformers "share power" as meaning that transformers "permit the sharing of power" because the parties agreed that transformers cannot share power.