Lufthansa Technik AG v. Astronics Advanced Electronic Systems Corp., 711 F. App'x 638

Patent: U.S. Patent No. 6,016,016 claims a voltage-supply apparatus for aircraft seat sockets that only supplies voltage when two contact pins of a plug are detected within a predetermined maximum time.
Safety goal: Prevents shocks from single-pin insertion (e.g., needles, paperclips) by requiring near-simultaneous detection of both pins.
Key claim language: Claim 1 includes a means-plus-function limitation “control means responsive to plug presence detection ... for rendering the voltage supplying means operative ... only if the time between the detection of a first contact pin and the subsequent detection of a second contact pin ... does not exceed a predetermined maximum time value.”
Procedural posture: AES moved for summary judgment that the terms “control means” and “subsequent detection” are indefinite; the district court held “control means” was sufficiently disclosed but found “subsequent detection” indefinite and granted invalidity. Lufthansa appealed.
Federal Circuit decision: The court reversed the district court’s conclusion on “control means,” holding that the specification fails to disclose adequate corresponding structure for the means-plus-function limitation and therefore that claims 1–10 are indefinite; it affirmed invalidity on that alternative ground and did not resolve the “subsequent detection” construction.

Issue	Lufthansa's Argument	AES's Argument	Held
Whether the claim term “control means” is definite under 35 U.S.C. § 112 ¶6	The specification (figure 3 and disclosure of control and supervision unit 60) and a skilled artisan would understand the structure (logic elements, microprocessors, PLAs, analog/digital circuitry); alternatively, the voltage switch is the corresponding structure	The specification fails to identify particular corresponding structure; the disclosure is a black-box control unit and does not call out specific logic elements — thus pure functional claiming	“Control means” is indefinite because the specification does not disclose adequate corresponding structure; claims 1–10 invalidated
Whether “subsequent detection” is definite / whether it excludes simultaneous detection	Lufthansa contends the claim language supports its construction; disputed whether prosecution history disavowed simultaneous detection	AES argues the prosecution history disclaimed simultaneous detection and the patent fails to define the boundary, leaving an ambiguous time range	Not decided: Federal Circuit affirmed on alternate ground (indefiniteness of “control means”) and did not reach proper construction of “subsequent detection”

Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831 (2015) (standards of review for claim construction and subsidiary factual findings)
Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir.) (2005) (claim terms construed by a person of ordinary skill in the art)
Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364 (Fed. Cir.) (2014) (indefiniteness reviewed de novo)
Biomedino, LLC v. Waters Techs. Corp., 490 F.3d 946 (Fed. Cir.) (2007) (means-plus-function requires specification to indicate corresponding structure)
Ergo Licensing, LLC v. Care-Fusion 303, Inc., 673 F.3d 1361 (Fed. Cir.) (2012) (generic recitation of control device insufficient to provide structure)
S3 Inc. v. NVIDIA Corp., 259 F.3d 1364 (Fed. Cir.) (2001) (calling out a standard component in the specification can supply adequate structure)
Blackboard, Inc. v. Desire2Learn, Inc., 574 F.3d 1371 (Fed. Cir.) (2009) (variety of ways to perform a function does not excuse a patentee from disclosing the claimed structure)