In Speedtrack, Inc. v. Amazon.com, Inc., [2020-1573, 2020-1660] (June 3, 2021), the Federal Circuit affirmed the district court’s final judgment of noninfringement of U.S. Patent No. 5,544,360, on a computer filing system.

At issue was the meaning of the claim term category descriptions. The district court concluded that category descriptions based on predefined hierarchical field-and-value relationships were disclaimed.

The Federal Circuit began by noting that claim terms “must be read in view of the specification.” Further, “the prosecution history can often inform the meaning of the claim language by demonstrating how the inventor understood the invention and whether the inventor limited the invention in the course of prosecution, making the claim scope narrower than it would otherwise be. The Federal Circuit said that “[a] patentee may, through a clear and unmistakable disavowal in the prosecution history, surrender certain claim scope to which he would otherwise have an exclusive right by virtue of the claim language.” Vita-Mix Corp. v. Basic Holding, Inc., 581 F.3d 1317, 1324 (Fed. Cir. 2009).

The Federal Circuit noted that during prosecution argued that the claims were not directed to a hierarchical system:

“Unlike prior art hierarchical filing systems,” the applicants explained, “the present invention does not require the 2-part hierarchical relationship between fields or attributes, and associated values for such fields or attributes.

The applicants continued: “At the most basic level, the present invention is a non-hierarchical filing system that allows essentially ‘free-form’ association of category descriptions to files without regard to rigid definitions of distinct fields containing values.”

The Federal Circuit further noted that in contrast, the applicants observed, the prior art was a hierarchical system that uses predefined field-and-value relationships.

The Federal Circuit said that “Prosecution disclaimer can arise from both claim amendments and arguments.” Tech. Props. Ltd. v. Huawei Techs. Co., 849 F.3d 1349, 1357 (Fed. Cir. 2017). In the instant case the Federal Circuit found both. The Federal Circuit that “[i]n no uncertain terms” the applicant[]s argued that the prior art had a ‘hierarchical’ relationship between fields and values that fell outside the scope of the amended claims.

The patentee argued that it distinguished the prior art on other grounds as well but the Federal Circuit said “that changes nothing.” The Federal Circuit said “[a]n applicant’s argument that a prior art reference is distinguishable on a particular ground can serve as a disclaimer of claim scope even if the applicant distinguishes the reference on other grounds as well.” Andersen Corp. v. Fiber Composites, LLC, 474 F.3d 1361, 1374 (Fed. Cir. 2007).

Ultimately, the doctrine of prosecution disclaimer ensures that claims are not construed one way in order to obtain their allowance and in a different way against accused infringers. That is what the patentee was attempting to do.