'732 claims a modular power box used for electrical conductors. In 2001, Panduit sued HellermannTyton for the illustrated previous design, which was settled with an agreement...

whereby HellermannTyton agreed not to make or sell "Subject Products." The Agreement defined "Subject Products"... as "all products, existing now or in the future, covered by any claim of the Panduit Patent." In exchange, Panduit waived its claims against HellermannTyton for infringement of the ’732 patent prior to the date of the Agreement.

In 2003, Panduit filed suit against HellermannTyton for breach... of the Agreement and for infringement of the ’732 patent based on HellermannTyton’s sale of the product depicted in the drawing below and designated as the "revised design." The only difference between the previous design and the revised design is that the wall abutting the trunking duct in the revised design is solid with no cutaway.

In February 2004, the district court stayed litigation of the infringement claim pending the outcome of a reexamination proceeding at the United States Patent and Trademark Office. However, the district court allowed the breach of contract claim to proceed.

The district court construed several claim limitations, and granted HellermannTyton summary judgment motion on the contract claim, that the accused device was not the same as the previous design, and hence not covered by the Agreement. Also, "the district court ruled as a matter of law that the accused device did not infringe the ’732 patent either literally or under the doctrine of equivalents."

Panduit appealed (CAFC 05-1337).

“Generally, interpretation of a settlement agreement is not an issue unique to patent law, even if arising in the context of a patent infringement suit.” Novamedix, Ltd. v. NDM Acquisition Corp., 166 F.3d 1177, 1180 (Fed. Cir. 1999). Accordingly, we apply the law of the appropriate circuit... Summary judgment is proper only if there are no genuine issues of material fact and the movant is entitled to judgment as a matter of law. See Fed. R. Civ. P. 56(c); Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 250 (1986). In determining whether there is a genuine issue of material fact, all facts and inferences are viewed in the light most favorable to the party opposing the motion. Davis, 368 F.3d at 782. Summary judgment is appropriate only when there is no genuine issue as to any material fact and where the moving party is entitled to judgment as a matter of law. Id.

Contract interpretation is ordinarily governed by state law. Unova, Inc. v. Acer Inc., 363 F.3d 1278, 1280 (Fed. Cir. 2004) (quoting Volt Info. Scis., Inc. v. Bd. of Trs. of the Leland Stanford Jr. Univ., 489 U.S. 468 (1989)). Here, the Agreement expressly provides that Illinois law governs interpretation. We therefore apply Illinois contract law principles to our interpretation of the Agreement. See id. Under Illinois law, interpretation of a contract is a question of law, which appellate courts review de novo. See Lumpkin v. Envirodyne Indus., Inc., 933 F.2d 449, 456 (7th Cir. 1991).

Under Illinois law, the plain language of the Agreement governs. Lumpkin, 933 F.2d at 456. If contract terms are unambiguous, then the inquiry is over. Id. However, if the language of the contract is ambiguous, then the court may consider extrinsic evidence to determine the intent of the parties. Id.

The CAFC agreed with the district court that the language of the Agreement was unambiguous in covering "only the specific device identified."

Settlement agreements, like consent judgments, reflect an agreement by hostile litigants on more than just contract terms; they reflect a compromise of contested legal positions in matters that are the subject of litigation. See United States v. Armour & Co., 402 U.S. 673, 681-82 (1971) (“Consent decrees are entered into by parties to a case after careful negotiation has produced agreement on their precise terms.”); Thatcher v. Kohl’s Dep’t Stores, Inc., 397 F.3d 1370, 1373-75 (Fed. Cir. 2005) (applying Illinois law, “[t]he consent judgment serves as a carefully crafted settlement agreement between the parties”). Because the language of the Agreement is not ambiguous, we do not look to the parties’ intent to include terms that are absent.

Panduit failed to convince either court that the opening portion of the accused device met the claim language. So "there is no genuine issue of material fact that the accused device does not literally infringe the ’732 patent."

Moreover, the doctrine of equivalents cannot be applied here. Application of the doctrine of equivalents is limited by the “all elements rule,” which provides that “the doctrine of equivalents does not apply if applying the doctrine would vitiate an entire claim limitation.” Asyst Techs., Inc. v. Emtrak, Inc., 402 F.3d 1188, 1195 (Fed. Cir. 2005) (citing Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 29 (1997)). Claim 1 of the ’732 patent requires an opening in an abutment portion through which wires may pass from a trunking duct into an offset power box. To extend the scope of the claim to encompass an accused device in which wires bypass the abutment portion altogether would necessarily read the “opening” limitation out of the claim. See Novartis Pharm. Corp. v. Eon Labs Mfg., 363 F.3d 1306, 1312 (Fed. Cir. 2004) (holding that a particulate dispersion inside the body cannot infringe under the doctrine of equivalents because it would vitiate the claimed requirement that the dispersion be prepared outside the body). The doctrine of equivalents cannot be applied because it would vitiate the “opening” limitation of the claim.

With "no genuine issue of material fact that the accused device does not meet the plain language of" the Agreement, or literally infringe '732, the CAFC affirmed the district court's summary judgment.