In Regents of the University of Minnesota v. AGA Medical Corp., No. 12-1167 (Fed. Cir. June 3, 2013), the Federal Circuit affirmed the district court’s partial dismissal of a suit brought by the University of Minnesota (“the University”) alleging that AGA Medical Corp. (“AGA”) infringed the University’s medical devices patents.
The University’s patents cover medical devices for repairing heart defects. Specifically, the two patents, derived from the same parent patent application, describe “septal occluders” used to allow blood to flow between the left and right sides of the heart. The University argued on appeal that the lower court erred in constructing the patent to require two distinct disks because such limitations are imported from outside the claims, and are unsupported by the patent specification.
The 6,077,291 patent describes the device as containing two disks that are “joined,” “connected,” or “affixed” to each other. The lower court, during Markman (i.e., claim construction) hearing, determined that such terms read in the context of the patent properly impose a structural limitation as requiring two physically separate disks.
A three judge Federal Circuit panel agreed with the lower court, opining that the claim construction was appropriate and that the lower court properly excluded AGA’s device from the University patents because AGA’s device is molded from a singular tube of mesh. The court reasoned that the intrinsic evidence, including the claim language, the specification, and the ordinary meaning of the terms, mandated such a construction. For example, the specification discloses ways of affixing the two disks and describes a possible third piece to be disposed between the two disks. Further, during prosecution, the University distinguished its invention from the prior art by emphasizing the “two disks” that allowed for more advantageous assembly. The prosecution history suggests that the ’291 patent was ultimately granted because the limitation that “a first membrane is connected to a central portion of a second membrane” made the patent novel. Subsequently, the court held that the intrinsic evidence necessitates an understanding that the device requires more than one disk.
The judge panel also held that the lower court had properly found patent 6,077,281 invalid as anticipated. The court concluded that the prior art’s “radial, umbrella like frame” was equivalent of the University’s peripheral frame structure. Thus, the primary question on appeal was whether the University disclaimed the prior art construction during the prosecution of a parent application. The University argued it had disclaimed the use of a radial frame as an equivalent of the peripheral frame on the application of ‘281’s predecessor patent, and that the disclaimer carried forward to the ‘281 patent.
However, the Court held that, even though the University effected a clear disclaimer of the radial frame with respect to the claim language, the disclaimer did not carry forward to the means-plus-function language used in the patent because the substance of each claim’s scope was materially different. Because the ’281 patent contains a different claim limitation than its subject matter, the disclaimer in the predecessor patent did not carry over to limit the range of equivalents nor negate the anticipatory invalidity.