Eidos Display, LLC v. Au Optronics Corporation, 779 F.3d 1360

Eidos Display, LLC and Eidos III, LLC sued multiple display manufacturers for infringing claim 1 of U.S. Patent No. 5,879,958, which claims a multi-step LCD manufacturing process (embodiment G among others).
The disputed claim limitation in step G8 reads: “a contact hole for source wiring and gate wiring connection terminals.” The parties disagreed whether this requires a single shared contact hole or separate contact holes for source and gate connection terminals.
Industry practice at the time formed separate contact holes for each connection terminal; no evidence showed manufacturers used a single shared hole.
The patent specification contains 17 embodiments (A–H, J, L–S). Embodiment D explicitly describes forming “a contact hole for a source wiring connection terminal and a contact hole for a gate wiring connection terminal.” The same language appears in other embodiments including G (claim 1).
The magistrate judge and district court found the limitation indefinite and granted summary judgment for defendants. Eidos appealed. The Federal Circuit reviewed claim construction and indefiniteness de novo and considered the intrinsic record dispositive.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the limitation “a contact hole for source wiring and gate wiring connection terminals” is definite under 35 U.S.C. § 112 ¶ 2	Eidos: term means separate contact holes for source and gate connection terminals (consistent with specification and industry practice)	Defendants: plain language supports a single shared contact hole for all connection terminals (or otherwise unclear)	Court: definite. Reading the claim with the specification and prosecution history, a POSITA would understand it to require separate contact holes for source and gate connection terminals; judgment of indefiniteness reversed.

Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120 (requirement that claims inform, with reasonable certainty, those skilled in the art about scope of the invention)
Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831 (deference to subsidiary factual findings in claim construction when present)
Phillips v. AWH Corp., 415 F.3d 1303 (en banc) (primacy of intrinsic evidence in claim construction)
Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364 (review standards for indefiniteness)
Ethicon Endo-Surgery, Inc. v. U.S. Surgical Corp., 149 F.3d 1309 (standard of review for summary judgment of indefiniteness)
Energy Transp. Grp., Inc. v. William Demant Holding A/S, 697 F.3d 1342 (consistent use of claim terms across the specification)
Masco Corp. v. United States, 303 F.3d 1316 (use of parent application prosecution history in claim construction)
Atmel Corp. v. Info. Storage Devices, Inc., 198 F.3d 1374 (interplay of claim construction and indefiniteness)
Honeywell Int’l v. Int’l Trade Comm’n, 341 F.3d 1332 (pre-Nautilus standard referenced by district court)
Source Vagabond Sys., Ltd. v. Hydrapak, Inc., 753 F.3d 1291 (limits on rewriting claims)