57 F.4th 1001
Fed. Cir.2023Background
- The patent (U.S. No. 7,412,877) claims a liquid pressurized viscometer that uses an "enlarged chamber" (chambers 45/49) between a top pressurization-fluid section and a lower measurement zone to prevent pressurization fluid from mixing with the test sample during pressurization.
- The disputed claim terms were: (1) "enlarged chamber" and (2) a means-plus-function phrase: "means for driving said rotor to rotate located in at least one bottom section."
- The district court held "enlarged chamber" indefinite (relying in part on dictionary definitions and Liberty Ammunition) and construed the means-plus-function term to cover magnetic coupling or direct drive "located in at least one bottom section."
- After the Markman order, the parties stipulated that multiple asserted claims were invalid (based on the indefiniteness ruling) and that others were not infringed (based on the means-plus-function construction); final judgment was entered for Chandler.
- On appeal the Federal Circuit vacated the indefiniteness finding and remanded, concluding the intrinsic record gives an objective functional boundary for "enlarged chamber"; the court affirmed the district court’s construction of the means-plus-function limitation.
Issues
| Issue | Plaintiff's Argument (Grace) | Defendant's Argument (Chandler) | Held |
|---|---|---|---|
| Whether "enlarged chamber" is indefinite | Term should be read by its purpose: a chamber large enough to hold excess sample so pressurization doesn't mix fluids in the lower measurement zone; thus definite. | Term is a term of degree requiring a baseline ("larger than what?") and lacks objective boundaries; indefinite. | Vacated district court; court held "enlarged chamber" means a chamber large enough to contain excess test sample prior to pressurization to prevent mixing in the lower measurement zone at maximum rated pressure (not indefinite). |
| Construction of "means for driving said rotor to rotate located in at least one bottom section" (35 U.S.C. §112, ¶6) | The phrase should be read to allow rotor-located drive structures (e.g., magnet holder or direct drive attached to rotor bottom); the location language modifies "rotor." | Phrase modifies the "means for driving" (not the rotor). The corresponding structure includes magnetic coupling components (magnet mount, gearbox/motor, driving/coupling magnets) or direct drive "at bottom of cell body," and known equivalents. | Affirmed district court: the prepositional phrase modifies the "means for driving," not the rotor; "bottom section" refers to the viscometer bottom section (so magnetic coupling components outside the pressure vessel fit); corresponding structures are magnetic coupling or direct drive at bottom of cell body, and equivalents. |
Key Cases Cited
- Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (claim construction must be informed by specification; inventor lexicography controls)
- Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576 (Fed. Cir. 1996) (specification is primary guide to claim meaning)
- Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898 (2014) (indefiniteness standard: claims must inform with reasonable certainty)
- Biosig Instruments, Inc. v. Nautilus, Inc., 783 F.3d 1374 (Fed. Cir. 2015) (intrinsic evidence can supply inherent parameters for a term of degree)
- Liberty Ammunition, Inc. v. United States, 835 F.3d 1388 (Fed. Cir. 2016) (terms of degree may require comparison to baseline when intrinsic record lacks objective boundary)
- Teva Pharm. USA, Inc. v. Sandoz, Inc., 574 U.S. 318 (2015) (claim construction: factual findings reviewed for clear error)
- Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364 (Fed. Cir. 2014) (analysis of terms of degree and need for objective boundary)
- Continental Circuits LLC v. Intel Corp., 915 F.3d 788 (Fed. Cir. 2019) (intrinsic vs. extrinsic evidence hierarchy)
- Cox Commc’ns, Inc. v. Sprint Commc’n Co., 838 F.3d 1224 (Fed. Cir. 2016) (indefiniteness legal conclusion; challenger bears clear-and-convincing burden)
- Nomos Corp. v. BrainLAB USA, Inc., 357 F.3d 1364 (Fed. Cir. 2004) (means-plus-function may incorporate disclosed structure and its mounting/location when specification teaches that configuration)