Markman Hearing Explained: How Judges Construe Patent Claims, and What Satius v. Samsung Shows

The parties present competing meanings for disputed claim terms, and the judge decides which meaning is correct. Under Phillips v. AWH Corp. (Fed. Cir. 2005) (en banc), claim words are "generally given their ordinary and customary meaning," which is the meaning to a person of ordinary skill in the art at the time of the invention, read in the context of the entire patent.

Phillips lists the sources a court may consult: "the words of the claims themselves, the remainder of the specification, the prosecution history, and extrinsic evidence concerning relevant scientific principles, the meaning of technical terms, and the state of the art."

Experts may be part of the process. In Teva v. Sandoz (2015), the parties presented the district court with competing fact-related claims by different experts, and the court resolved the issues of fact that divided them. Even so, the Supreme Court in Markman quoted a treatise explaining that in the actual interpretation of the patent the court "proceeds upon its own responsibility, as an arbiter of the law."

A claim construction ruling can end a case. In Satius, the district court concluded in its claim construction order that the asserted claims were indefinite and then entered final judgment of invalidity.

Sources: Phillips v. AWH Corp.; Teva v. Sandoz, 574 U.S. 318; Markman v. Westview, 517 U.S. 370; Satius v. Samsung

Markman owned a patent on an inventory control system for dry-cleaning stores. A jury found that Westview's product infringed, but the district court granted judgment as a matter of law for Westview, reasoning that its device could not track "inventory" as that term is used in the claim. The Federal Circuit affirmed, and a unanimous Supreme Court affirmed on April 23, 1996.

The Court found no direct antecedent of modern claim construction in the historical sources, so the Seventh Amendment did not require a jury. It then gave these reasons for assigning construction to the court:

• Precedent. Justice Curtis described the first issue in a patent case, construing the patent, as "a question of law, to be determined by the court," and the second, infringement, as "a question of fact, to be submitted to a jury."
• Skill. "The construction of written instruments is one of those things that judges often do and are likely to do better than jurors unburdened by training in exegesis."
• Coherence. The judge is better placed to decide whether an expert's proposed definition fits the specification and claims as a whole.
• Uniformity. The Court saw uniform treatment of a given patent as an independent reason to give all construction issues to the court.

Sources: Markman v. Westview, 517 U.S. 370

Phillips, decided en banc on July 12, 2005, sets the hierarchy of evidence that judges apply when construing claims.

The specification may show a special definition the patentee gave a term, and in that case "the inventor's lexicography governs." It may also show an intentional disclaimer of claim scope, which is regarded as dispositive.

Phillips rejected the Texas Digital approach, which started from dictionary definitions, because it "placed too much reliance on extrinsic sources such as dictionaries, treatises, and encyclopedias and too little on intrinsic sources." It also warned that "conclusory, unsupported assertions by experts as to the definition of a claim term are not useful to a court."

Sources: Phillips v. AWH Corp.

In Teva v. Sandoz (decided January 20, 2015), the Federal Circuit had reviewed every part of a district court's construction of "molecular weight" de novo, including subsidiary facts. The Supreme Court held that the appellate court must apply a "clear error," not a de novo, standard to the district court's resolution of subsidiary factual matters, under Federal Rule of Civil Procedure 52(a)(6).

Satius applied the same split to indefiniteness: the Federal Circuit reviews governing legal standards and intrinsic evidence de novo, and "any relevant factual findings about extrinsic evidence for clear error."

Sources: Teva v. Sandoz, 574 U.S. 318; Satius v. Samsung

Satius sued Samsung in 2018 in the District of Delaware over claims 1, 11 and 18 of U.S. Patent No. 6,711,385. Claim 1 recites "[a] communications apparatus for transmitting electric or electromagnetic signals over air." The case was stayed for reexamination, in which the PTO rejected claim 1 and upheld dependent claims 11 and 18. After the stay lifted, the district court proceeded with claim construction, held all three claims indefinite because transmitting electric signals over air is an undisputed scientific impossibility, and entered final judgment of invalidity.

In a precedential opinion by Chief Judge Moore, decided October 1, 2026, the Federal Circuit affirmed the judgment, but on a different ground:

1. Construction. The court construed "transmitting electric . . . signals over air" to mean transmitting signals over air in electric form. It rejected Satius's reading that the electric signal is transformed into an electromagnetic signal, noting that transmitting signals over the air is not the same as transmitting them to the air, and that courts "may not redraft claims . . . to make them operable or to sustain their validity."
2. Indefiniteness. "Indefiniteness is not the same as impossibility." Because the claims inform skilled artisans of their scope with reasonable certainty, they are definite under § 112(b). The court distinguished Synchronoss, where the claims were nonsensical and the specification showed they did not set forth what the inventor regarded as the invention.
3. Enablement. The district court had declined to rule on enablement, finding it waived. The Federal Circuit reached the issue anyway because it was briefed, there was no factual dispute, and the answer was so evident that remand would serve no purpose.
4. Result. The claims are invalid for lack of enablement under § 112(a) because they "explicitly cover a scientific impossibility that cannot be made or used by a skilled artisan."

See also our summary of Satius v. Samsung.

Sources: Satius v. Samsung; 35 U.S.C. § 112

• Courts construe the claim as written. Where claims are "susceptible to only one reasonable construction," the court construes the patentee's version of the claim as drafted, even if that produces an inoperable result.
• Different words, different meanings. The court applied the general assumption that "different terms have different meanings" to separate "over air" from "to the air."
• No per se impossibility rule. The court stated there is "no per se rule that a claim covering inoperable embodiments is necessarily indefinite," and it called the district court's contrary statement incorrect.
• Conclusory experts carry little weight. In a footnote, the court described the testimony of Samsung's expert, as credited by the district court, as "conclusory extrinsic evidence" that contradicted Samsung's own position that the term clearly covers an impossibility.
• Enablement looks at full scope. Quoting Amgen v. Sanofi, the court said "the specification must enable the full scope of the invention as defined by its claims" and "The more one claims, the more one must enable."

The district court had said that "the claim construction stage is not typically the right time to be addressing ineligibility or lack of enablement issues anyway." The Federal Circuit did not dispute that statement, but it saw no bar to resolving enablement on appeal under the discretion recognized in Singleton v. Wulff and the factors listed in Icon Health & Fitness.

In our view, the practical lesson is that winning a construction can cut both ways: a patentee whose reading is rejected may escape indefiniteness and still lose the claims on enablement if the construed scope includes inoperable embodiments. More examples are collected under claim construction decisions.

Sources: Satius v. Samsung

Section 112(a) requires a written description enabling "any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same." Section 112(b) requires claims "particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention."

Under 35 U.S.C. § 282(a), each claim is presumed valid independently of the others, dependent claims are presumed valid even though they depend on an invalid claim, and the burden of proving invalidity rests on the party asserting it. Section 282(b)(3)(A) makes failure to comply with § 112 a defense, except that failure to disclose the best mode cannot invalidate a claim. Satius adds that "Indefiniteness must be proven by clear and convincing evidence."

Sources: 35 U.S.C. § 112; 35 U.S.C. § 282; Satius v. Samsung