Littelfuse, Inc. v. Mersen USA EP Corp., Appeal No. 2021-2013 (Fed. Cir. Apr. 4, 2022)‎

Our Case of the Week focuses on the issue of claim construction, and, more specifically, the doctrine ‎of claim differentiation. ‎

The patent at issue was directed to a “fuse end cap for providing an electrical connection between a ‎fuse and an electrical conductor.” The patent described three embodiments of end caps: a “machined ‎end cap,” a “stamped end cap,” and an “assembled end cap.” The first two may be made from a single ‎piece of material that is either machined or otherwise formed into the end cap. The last is made from ‎two separate pieces of material.‎

Claim 1 of the patent recited an end cap with a “mounting cuff,” a “terminal,” and a “fastening ‎stem.” Claims 8 and 9 recited, respectively, “[t]he fuse end cap of claim 1, wherein the mounting cuff ‎and the terminal are [machined/stamped] from a single, contiguous piece of conductive material.”‎

During prosecution, the examiner issued a restriction requirement, noting that the three types of end ‎cap were three different species. Littelfuse responded by electing to prosecute the species ‎corresponding to the “assembled end cap” embodiment. The examiner then withdrew dependent ‎claims 8 and 9, which both corresponded with machined or stamped end cap embodiments. But after ‎further prosecution, the examiner allowed those claims back in based on Patent Office ‎procedures. This was because claim 1, a generic claim, was allowed, and the dependent claims were ‎compatible with allowed claim 1.‎

During litigation, the district court construed the term “fastening stem” to mean a “stem that attaches ‎or joins other components.” Thus, the court’s construction inherently narrowed the scope of the claim ‎to multi-component end caps, like the assembled end cap embodiment. The district court’s ‎construction precluded a “machined end cap” or a “stamped end cap” formed from a single piece of ‎material. Following a stipulation of summary judgment, Littelfuse appealed.‎

The Federal Circuit reversed. Its critical holding is succinct:‎

By definition, an independent claim is broader than a claim that depends from it, so if a ‎dependent claim reads on a particular embodiment of the claimed invention, the ‎corresponding independent claim must cover that embodiment as well. . . . Otherwise, ‎the dependent claims would have no scope and thus be meaningless. A claim ‎construction that leads to that result is generally disfavored. . . . Accordingly, the ‎recitation of a single-piece apparatus in claims 8, 9, 19, and 20 is persuasive evidence ‎that claims 1 and 10 also cover a single-piece apparatus.‎

The Court noted that “the presumption of differentiation in claim scope is not a hard and fast rule,” ‎and that “any presumption created by the doctrine of claim differentiation ‘will be overcome by a ‎contrary construction dictated by the written description or prosecution history.’” However, the ‎specification here supported a broader construction, and the prosecution history did not overcome ‎the presumption.‎

The Court also noticed that a “fastening stem” could still be present in a single-piece apparatus, given ‎its structure as disclosed and claimed in the patent. The Court went on to confirm that a “fastening ‎stem” must both include a “stem” and must “fasten.” ‎

The case was reversed and remanded to the district court to adopt a claim construction consistent with ‎the court’s guidance, but not precluding a single-component end cap.‎

The opinion can be found here.‎


Roche Diagnostics Corporation v. Meso Scale Diagnostics, LLC, Appeal Nos. 2021-1609, -1633 (Fed. Cir. ‎April 8, 2022)‎

In an appeal from a district court decision, the Court addressed a licensing dispute in a lengthy opinion ‎covering numerous legal and factual issues. Roche filed for declaratory judgement for non-‎infringement of patents, the rights to which Meso claimed to hold via an exclusive license. Meso ‎counterclaimed for infringement. The jury found that Meso held an exclusive license to the asserted ‎patent claims and that Roche directly infringed one claim, induced infringement of three claims, and ‎did so willfully. The district court granted Roche judgement as a matter of law on willfulness, denied ‎Meso’s motions to enhance damages, and granted Roche’s request for a finding of non-infringement ‎on three additional patents, due to their being compulsory counterclaims that Meso failed to bring in ‎its counterclaim. Given insufficient reason to overturn the district court’s finding that the patents-in-‎suit were within the scope of rights licensed exclusively to Meso, the Federal Circuit affirmed on direct ‎infringement. On induced infringement, the Federal Circuit reversed the district court on both the ‎intent and inducing acts prongs. The Federal Circuit agreed with Roche that, because the intent ‎standard for induced infringement is similar to the intent standard for willfulness and enhanced ‎damages, the same facts that led to JMOL on willfulness and denial of enhanced damages should have ‎led to JMOL on induced infringement. The Federal Circuit also agreed that, although the induced ‎infringing acts occurred during the six-year window prior to suit, because the acts that induced the ‎infringing acts occurred before the six-year window, the induced acts prong was not met. Because the ‎Federal Circuit reversed on induced infringement, it vacated for a new trial on damages. The Federal ‎Circuit also vacated the non-infringement finding as to the three additional patents, agreeing with ‎Meso that a counterclaim that is compulsory but not brought is barred in subsequent actions, but not ‎in a present action. The Federal Circuit did not reach the question of whether Roche’s complaint was ‎too generic to trigger the compulsory counterclaim rule, saving that determination for any district court ‎called to hear a subsequent infringement action by Meso concerning the additional patents. In dissent, ‎Judge Newman argued that Roche cannot infringe patents it owns, and, detailing the complicated ‎history of the patents-in-suit, that Roche had owned the patents since 2007.‎

The opinion can be found here.‎

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