Context Is Key in Claim Construction

By on April 20, 2023
Posted In Patents

The US Court of Appeals for the Federal Circuit reiterated that intrinsic evidence trumps extrinsic evidence in determining the meaning of claim terms. Sequoia Technology, LLC v. Dell, Inc. et al., Case Nos. 21-2263; -2264; -2265; -2266 (Fed. Cir. Apr. 12, 2023) (Stoll, Lourie, Dyk, JJ.)

Sequoia Technology owns a patent directed to data storage methods involving storing the same data across multiple physical disk drives to make up a virtual disk drive. Sequoia asserted the patent against several companies, all based on a product sold by Red Hat. During litigation, the parties disputed the construction of the terms “computer-readable recording medium,” “disk partition” and “logical volume.” Related to the latter two claim construction issues, the parties construed the term “used or not used” in the context of an extent’s usage in an “extent allocation table.”

The district court adopted Red Hat’s construction of “computer-readable recording medium” to include transitory media (i.e., signals or waves). The district court found no clear language in the specification that excluded transitory media and found Red Hat’s extrinsic evidence to be persuasive, “particularly given the lack of any substantive rebuttal from Sequoia’s expert.” For “disk partition” and “logical volume,” the district court agreed with Red Hat and construed “disk partition” to mean a “section of a disk that is a minimum unit of a logical volume” and “logical volume” to mean an “extensible union of more than one disk partition, the size of which is resized in disk partition units.” These constructions require that a logical volume is constructed by whole disk partitions, not subparts of disk partitions such as extents. The district court also construed the phrase “used or not used” in the limitation “extent allocation table for indicating whether each extent in the disk partition is used or not used,” adopting Red Hat’s construction that “used or not used” means that an extent “is or is not storing information.”

Following claim construction, the parties stipulated that under the district court’s claim construction of “logical volume” and “disk partition,” the accused products did not infringe the asserted claims. The parties also stipulated that under the district court’s construction of “computer-readable recording medium,” certain claims were subject matter ineligible under 35 U.S.C. § 101 as including transitory media. Sequoia appealed.

The Federal Circuit concluded that the district court erred in construing “computer-readable recording medium.” Starting with the claim language, the Court noted that the claim recited a “computer-readable recording medium storing instructions” and not simply a “computer-readable medium.” The Court reasoned that an ordinarily skilled artisan would understand transitory signals to be incompatible with the claimed invention because such fleeting signals would not persist for sufficient time to store instructions. Turning to the specification, the Court explained that although the specification did use open-ended “including” language to describe a computer-readable medium, the relevant portion of the specification defined computer-readable media as “including compact disc read only memory (CDROM), random access memory (RAM), floppy disk, hard disk, and magneto-optical disk,” all of which are non-transient forms of storage media hardware. The Court further reasoned that Red Hat’s proposed construction to include transient signals did not make sense in the context of the claims, which defined hardware storage and were silent as to any type of signal. Rather, the specification made clear that the invention provides a means of “storing a program or data structure,” which the Court described as being “irreconcilable with a transitory signal.”

The Federal Circuit rejected Red Hat’s extrinsic evidence, which in the Court’s view only demonstrated that inventors acted as their own lexicographers in the specification. The Court reiterated the claim construction maxim that when weighing expert testimony, “a court should discount any expert testimony ‘that is clearly at odds with the claim construction mandated by . . . the written record of the patent.’” As the Court put it, “context is key in claim construction.”

The Federal Circuit next turned to the district court’s constructions of “disk partition” and “logical volume.” Sequoia argued that the claims did not recite “whole disk partition” or other similar language defining the size or completeness of the disk partition. Starting again with the claim language, the Court noted that the claims likewise failed to recite “parts” or “portions” of disk partitions or any other language defining the disk partitions to be anything less than whole disk partitions. The Court then looked to the specification, which defined a disk partition to be “a [logical] volume construction unit.” Sequoia argued that metadata could be minimized even if portions of disk partitions were used to construct logical volumes. The Court rejected Sequoia’s argument as “untethered” to the specification’s express language, which was the only explanation provided in the patent as to how the object of the claimed invention was achieved.

Continuing with its assessment of the intrinsic evidence, the Federal Circuit looked to the prosecution history where the applicant made statements about the meaning of “disk partition” as a logical volumes smallest construction unit. The applicant distinguished two prior art references on the basis that the prior art gathered “subsets of disk drives . . . to form a logical volume,” and further stated that the patent’s logical volumes are formed “at the level of the disk partitions.” The Court concluded that these statements characterizing the invention to overcome a prior art challenge were clear and could not reasonably support a construction allowing for sub-portions of disk partitions to be assembled into logical volumes.

Finally, the Federal Circuit addressed the recitation “used or not used” in the claim limitation “an extent allocation table for indicating whether each extent in the disk partition is used or not used.” Sequoia argued that this limitation supported its construction of disk partition (i.e., that “disk partition” includes both whole and partial disk partitions) because an “extent” is a partial disk partition and “used or not used” should be construed to mean whether a given extent is used or not used in the computer-readable recording medium storing instructions. Red Hat argued that “used or not used” refers to whether a particular extent in the logical volume is in use for storage, not whether a partial disk partition is present or absent from the device.

Based on the claim language alone, the Federal Circuit could not find support for either party’s construction over the other. The Court resolved this issue by returning to the specification’s express definition of disk partition as “a [logical] volume construction unit.” The Court reasoned that if “used” means “used in the logical volume,” then the extent allocation table recited in the claims would be superfluous because whole partitions make up the logical volume and extents would necessarily be used. The Court also considered a prior publication by the inventors in which “use” of extents referred to usage for storage purposes. The Court was careful to note that it was not relying on the paper (which was directed to a system outside the scope of the claims) to dictate the meaning of usage of an extent. Rather, the Court clarified that the inventors’ previous publication evidenced that “use” of an extent can mean that the extent is utilized for storage. The Court concluded that the district court’s construction was therefore reasonable.

Accordingly, the Federal Circuit reversed the district court’s conclusion that certain claims were ineligible under 35 U.S.C. § 101 but affirmed the district court’s noninfringement finding.

Practice Note: When drafting and prosecuting a patent application, patent practitioners should bear in mind the hierarchy of evidence a court will consider: the claim language itself, the specification, the prosecution history and, finally, extrinsic evidence to the extent it is not inconsistent with the intrinsic evidence.

Brennen Baylor
Brennen Baylor focuses his practice on intellectual property matters in the life sciences industry. He prosecutes patent applications related to small molecules, pharmaceutical macromolecules, medical devices, agricultural chemistry, nutraceuticals, synthesis and use of nucleic acids and polypeptides, cell culturing systems and apparatuses, methods of culturing cells and methods of preparing tissue grafts. Brennen also has experience advising clients on inventions in the fields of chemical engineering systems, lithium batteries, manufacturing flooring composites, 3D printer filament compositions, and cellulose-based packaging materials. Read Brennen Baylor's full bio.