Ambiguous Phrase in Claims Not Indefinite Where Intrinsic Evidence Resolves the Ambiguity


Eidos Display, LLC v. AU Optronics Corp., ___ F.3d ___ (March 10, 2015) (Wallach, Taranto, CHEN) (E.D. Tex.: Davis) (1 of 5 stars)

Federal Circuit reverses summary judgment of indefiniteness. The case relates to the manufacture of liquid crystal displays. The Federal Circuit held that the term "a contact hole for source wiring and gate wiring connection terminals" would be understood by the skilled artisan "to call for separate, different contact holes for the source wiring connection terminals and gate wiring connection terminals, rather than one shared contact hole." Slip op. at 10. Although the phrase, taken alone, might seem ambiguous to one not knowledgeable in the field, the scope of the limitation was still reasonably certain to the skilled artisan, because (1) it was undisputed that the state of the art had always called for separate contact holes; (2) nothing in the specification described deviating from that known industry practice; (3) the prosecution history of the application to which the patent claims priority contained claims using the same language to refer to an embodiment in the specification with separate contact holes; and (4) the specification equated the disputed limitation with forming separate contact holes for the source and gate wiring terminals. This construction did not constitute "rewriting" those claim limitations: "Determining how a person of ordinary skill in the art would understand the different from rewriting the limitation." Slip op. at 15.

Authors: Chris W. Dryer, Michael C. Tyler