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Product-by-process analysis dooms challenged patent

February / March 2023 IP Newsletter

The U.S. Court of Appeals for the Federal Circuit has invalidated a previously issued patent based on what it deemed a “product-by-process” claim. The court found that it wasn’t enough that the process part of the claim was different from existing processes — the product part also needed patentable differences.

Housing problems

The patentee owns a patent on ultrasonic flow meter housings. The meters are used for calculating a consumed quantity of water, heat, cooling, gas or the like.

The housing, which protects electronic components, is described as “in the form of a monolithic polymer structure being cast in one piece.” The patent states that the invention can be fabricated with fewer steps than existing meters because only a single step is used to form the monolithic polymer structure.

A competitor petitioned the Patent Trial and Appeal Board (PTAB) for an inter partes review (IPR) of the patent. Under IPR, the PTAB can reconsider and cancel an already-issued patent based on certain types of “prior art.” The board found the invention unpatentable as obvious or anticipated by a European patent.

A lack of difference

The patentee argued that the PTAB erred when it interpreted the term “cast in one piece” to be a product-by-process claim element. A product-by-process claim is one in which the patent claims a product, at least in part, by the process by which it’s made.

Product-by-process claims allow an applicant to claim an otherwise patentable product that resists definition by any way other than the process by which it’s made. When determining the validity of these claims, courts focus on the product, rather than the process of making it — because a product disclosed in prior art isn’t patentable even if made by a new process.

If the process produces structural and functional differences that distinguish the claimed product from the prior art, those differences are relevant to the patentability analysis. The PTAB found that the patentee presented no evidence that the process here provided distinguishing structural and functional differences. It therefore concluded that the product-by-process claim shouldn’t be considered as part of an anticipation or obviousness analysis.  

On appeal, the Federal Circuit affirmed that the “cast in one piece” element was indeed a product-by-process claim. The claim language, it said, claimed a process because it described the structure “being” cast in a particular way. The court found further support for its conclusion in a patent disclosure that discussed the device’s fabrication process.

The appellate court also affirmed the PTAB’s finding that there were no functional or structural differences between polymer structures cast in a single mold versus multiple molds. The patentee contended that various structures can’t be cast in a single mold using conventional molding technologies.

Even if true, though, the patentee didn’t identify functional and structural differences between a structure “cast in one piece” and one manufactured using another method. The alleged difference the patentee did identify was “detached from the claims,” as the patent claim said the structure should be cast in “one piece,” not “one mold.”

Threat eliminated

The court’s ruling means the patent is no longer valid, and the competitor that brought the challenge need not worry about infringement claims by the patentee. These results illustrate the importance of carefully crafted patent application language.