IP Law Daily, PATENT—Fed. Cir.: PTAB’s invalidation of cooling system patent claims affirmed on appeal, (Apr 9, 2026)

By Saurabh Kashyap, B.A., M.A., LL.B., LL.M.

Patent Trial and Appeal Board (PTAB) correctly construed the claim term heat exchanger; the patentee’s secondary considerations were found to lack nexus and evidentiary weight.

In a non-precedential decision, the U.S. Court of Appeals for the Federal Circuit affirmed the Patent Trial and Appeal Board’s (PTAB or Board) decision holding all challenged claims of two patents owned by Manufacturing Resources International, Inc., unpatentable as obvious. The appellate court agreed with the Board’s construction of the term “heat exchanger” and concluded that the patentee’s objective evidence of non-obviousness was entitled to little weight, thereby sustaining the Board’s invalidity findings in full (Manufacturing Resources International, Inc. v. Squires, No. 24-2224 (Fed. Cir. Apr. 7, 2026)).

Background. Manufacturing Resources International, Inc. (MRI), a company that develops thermal management systems for electronic displays, appealed against the Director of the United States Patent and Trademark Office, who intervened to defend the Board’s ruling following inter partes review proceedings initiated by Samsung Electronics entities.

The dispute involved U.S. Patent Nos. 10,506,740 (the ’740 patent) and 11,013,142 (the ’142 patent), both directed to cooling systems for electronic displays. The patented technology used two distinct airflow paths, an open-loop ambient air flow and a closed-loop gas circulation path, that interacted through a common “heat exchanger.” The system was designed to regulate temperature by transferring heat between the two airflow paths while maintaining separation within the display structure.

Samsung Electronics Co., Ltd. and Samsung Electronics America, Inc. filed petitions for inter partes review challenging multiple claims of both patents on obviousness grounds. The PTAB instituted review and ultimately determined that all challenged claims were unpatentable. In reaching its decision, the Board construed “heat exchanger” broadly, finding that it did not require enclosed channels or tubes. The Board also found that MRI’s objective indicia of non-obviousness—such as commercial success and industry praise—were entitled to little weight due to a lack of sufficient nexus to the claimed invention. MRI appealed both the claim construction and the Board’s treatment of its secondary considerations.

Court analysis. On claim construction, the Federal Circuit reiterated that such determinations are questions of law reviewed de novo. Citing Intel Corp. v. Qualcomm Inc., 21 F.4th 801 (Fed. Cir. 2021), the court emphasized that intrinsic evidence—claims, specification, and prosecution history—controls the analysis. The court found that the plain language of the claims did not impose any structural limitation requiring a heat exchanger to include enclosed channels or tubes. Instead, the claims described the component’s placement and function without restricting its form.

The court further relied on Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc), explaining that although the specification is central to claim interpretation, it cannot be used to import limitations absent clear intent. Here, the shared specification described multiple types of heat exchangers and expressly stated that “many types” could be used. While certain embodiments included enclosed flow paths, the specification did not define the invention as limited to those configurations.

Rejecting MRI’s arguments based on the specification and priority applications, the court invoked Thorner v. Sony Computer Entertainment America LLC, 669 F.3d 1362 (Fed. Cir. 2012), reiterating that a patentee must clearly express an intent to redefine a term or disavow its ordinary meaning. The court found no such clear lexicography or disclaimer. It also concluded that the provisional applications cited by MRI did not establish that “heat exchanger” was limited to enclosed-channel structures. Accordingly, the Federal Circuit affirmed the Board’s broader construction.

Turning to secondary considerations, the Federal Circuit upheld the Board’s conclusion that MRI’s evidence of non-obviousness deserved little weight. The court noted that MRI had raised materially similar arguments in a related appeal, which it had recently rejected. It agreed with the Board that MRI failed to demonstrate a sufficient nexus between the alleged commercial success and the specific claimed features, and that the evidence did not meaningfully rebut the strong showing of obviousness based on the prior art.

The court also rejected MRI’s remaining arguments as unpersuasive, finding no reversible error in the Board’s analysis. It emphasized that the Board had applied the correct legal standards and reasonably evaluated both the prior art and the secondary considerations.

Thus, the Federal Circuit affirmed the PTAB’s decision in full, sustaining the invalidation of all challenged claims of the ’740 and ’142 patents.

The Case is No. 24-2224.

Judge: Stoll, K.

Attorneys: David A. Reed (Kilpatrick Townsend & Stockton LLP) for Manufacturing Resources International, Inc. Fahd H. Patel, U.S. Patent and Trademark Office, for John A. Squires.

Companies: Manufacturing Resources International, Inc.

Cases: Patent FedCirNews