In Lowe v. ShieldMark, Inc., No. 2021-2164, 2022 WL 636100 (Fed. Cir. Mar. 4, 2022), the United States Court of Appeals for the Federal Circuit (“Federal Circuit”) vacated and remanded a district court’s decision granting summary judgment of noninfringement and affirmed the district court’s dismissal of the plaintiff’s declaratory judgment claim and denial of attorney fees.


Lowe and ShieldMark both sell floor marking tape. Id. at *2. Each party owns a patent that covers its tape product. Id. Lowe owns U.S. Patent No. 10,214,664 (“the ’664 patent”), which is directed to an improved tape with features that prevent floor cleaning devices or skids from unintentionally lifting or delaminating tape from the floor. Id. at *3. ShieldMark owns U.S. Patent No. 10,738,220 (“the ’220 patent”), which is directed to a polymeric adhesive tape with features that prevent wearing, tearing, cracking, and breaking from heavy and repeated traffic. Id. at 5.

In April 2019, Lowe sued ShieldMark for infringement of certain claims of the ’664 patent. In response, ShieldMark raised a defense of noninfringement. Id. at *6. In August 2020, after ShieldMark’s ’220 patent issued, ShieldMark amended its answer to add a counterclaim that Lowe infringed its newly issued patent. Id. at *7. In response, Lowe amended its complaint to include a declaratory judgment claim for invalidity and unenforceability of the ’220 patent. Id.

Subsequently, Lowe altered the design of its marking tape such that “it arguably no longer infringe[d]” the ’220 patent. Id. And ShieldMark, in turn, provided Lowe a covenant not to sue for any past or present infringement the ’220 patent. Id.

In March 2021, after the covenant not to sue was in place, ShieldMark moved to (1) voluntarily dismiss with prejudice its ’220 patent infringement suit against Lowe, and (2) dismiss Lowe’s corresponding declaratory judgment claim for lack of subject matter jurisdiction. Id. at *7-8. Lowe opposed both motions and filed a motion for summary judgment of invalidity and unenforceability of the ’220 patent. Id. at *8. In reviewing the parties’ motions, the district court issued two decisions. First, the district court granted summary judgment that ShieldMark did not infringe Lowe’s ’664 patent claims. Id. Second, the district court dismissed all claims concerning ShieldMark’s ’220 patent. Id. at *9.

Subsequently, Lowe appealed the district court’s decisions. Id.

Federal Circuit Decision

The Federal Circuit (1) vacated and remanded the district court’s decision granting summary judgment of noninfringement and (2) affirmed the district court’s dismissal of Lowe’s declaratory judgment claim and denial of attorney fees. Id. at *2, 20.

Interestingly, when addressing Lowe’s argument that the district court erred in granting summary judgment of noninfringement, the Federal Circuit held that the district court improperly narrowed the ’664 patent’s claim terms during construction. Id. at *10-16.

During its construction of three terms, the Federal Circuit explained that the lower court erred by importing terms from the specification into the claims. Id. at *11. The Federal Circuit explained that the district court’s construction improperly narrowed the claims to certain embodiments. Id. (stating that the Federal Circuit has “repeatedly ‘cautioned against limiting the claimed invention to preferred embodiments or specific examples in the specification.’” citation omitted).

For example, the district court construed one of the disputed claim terms — “lateral edge portion”—to mean “the portion of the floor marking tape from the shoulder to the edge of the tape when viewed in the cross section.” Id. at *11. This construction was used to find noninfringement by ShieldMark, in part, because ShieldMark’s floor marking tape had “a single, flat lower surface without shoulders.” Id. at 6-7. Upon review, the Federal Circuit found that the district court erroneously construed the claim language to include limiting language that was not present in the claims themselves. The Federal Circuit explained that the district court’s limiting construction was incorrect because (1) principles of law warn against constructions that render claims “superfluous,” (2) the specification intrinsically showed that certain embodiments didn’t have shoulders, and (3) the parent of the ’664 patent extrinsically supported a determination that the ’664 patent claims were not so limited by expressly reciting a floor marking tape with shoulders. Id. at *12. The Federal Circuit further explained, even where every figure in a patent shows a certain feature, a patent is not necessarily limited to the embodiments of the invention claimed in those figures. Id. at *13. The court applied this reasoning to its construction of the other two claim terms at issue before reversing and remanding (“lower surface of each lateral edge portion being a flat coplanar extension of the lower surface of the body” and “central body portion”).

The Federal Circuit affirmed the district court’s dismissal of Lowe’s declaratory judgment claim because the district court lacked subject matter jurisdiction; in light of the covenant not to sue and district court’s dismissal, a substantial controversy between the parties did not exist.


This decision serves as an important reminder that practitioners must carefully consider the language and figures used when drafting patent applications. At the top of the evidentiary hierarchy that is used during claim construction is the language of the claims and the support found in the specification. “[A] court may not read into a claim a limitation from a preferred embodiment, if that limitation is not present in the claim itself.” Bayer AG v. Biovail Corp., 279 F.3d 1340, 1348 (Fed. Cir. 2002). Of course, the practitioner should also be cautioned that the above claim construction principle has limits: “unless that embodiment is in fact the entire invention presented.” Vulcan Eng’g Co. v. Fata Aluminum, Inc., 278 F.3d 1366 (Fed. Cir. 2002). And remember, from Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc), the specification is the single best guide to construing a claim.

Following the four corners of the patent, the prosecution history of a patent, as well as its family’s prosecution history can provide important clues during claim construction. Practitioners should carefully consider the patent application’s family history (when relevant) and their use of words during drafting. Likewise, when litigating, practitioners should carefully review a patent’s language and prosecution history when developing a claim construction position.