The Federal Circuit has reversed the District of Delaware’s ruling that added an inventor to a patent. The Federal Circuit found that the contribution by the added inventor was not significant when measured against the invention as a whole, thereby defeating the bid to change inventorship.
The patent owner Hormel Foods obtained a patent for a two-step method of precooking bacon and meat pieces. The first step required preheating the meat to seal in desired flavors. The second step used a higher temperature to prevent unwanted flavors. The patent had three independent claims, including one claim that required a microwave oven to be used for the first step, and another claim that gave the option of a microwave oven, an infrared oven or hot air to be used for the first step. The method was researched and developed under a joint agreement between Hormel and another company that was eventually called HIP.
Approximately three years after the patent issued, HIP filed suit alleging that one of its employees should be either a sole inventor or a joint inventor. HIP contended that the employee had contributed the infrared heating concept during discussions of the testing research. The district court ruled in favor of HIP, finding that the employee was a joint inventor. On appeal, Hormel argued that the district court erred by finding that the employee’s alleged contributions merited joint inventorship, and by finding that HIP had met the evidentiary requirements for corroboration of the employee’s testimony.
The Federal Circuit began its analysis by setting out the burdens for joint inventorship and the three-part test from Pannu v. Iolab Corp., 155 F.3d 1344 (Fed. Cir. 1998). A person claiming to be a joint inventor of an issued patent must prove the claim by clear and convincing evidence. To qualify as a joint inventor, the person must (1) contribute in some significant manner to the conception or reduction to practice of the invention; (2) make a contribution to the claimed invention that is not insignificant in quality when that contribution is measured against the dimension of the full invention; and (3) do more than merely explain to the real inventors well-known concepts and/or the current state of the art.
The Federal Circuit focused its analysis on the second Pannu factor. The court found that the employee’s contribution of using an infrared oven in the first step was insignificant in quality to the claimed method. The court juxtaposed the patent’s discussion of using different heat sources. Use of an infrared oven was discussed only once in the specification, and even then only as an alternative to a microwave oven. Further, as a claim limitation, use of an infrared oven was only in one of the three independent claims, and only as part of a Markush group. In contrast, use of a microwave oven featured heavily in the specification and claims. In particular, the examples and figures showed using a microwave oven or other heat sources, not an infrared oven. The court found that the microwave oven was central to the cooking methods disclosed.
The Federal Circuit did not analyze the other Pannu factors, stating that the employee’s failure to meet any one factor doomed the bid for joint inventorship. Further, the court explained that it did not need to reach the issue of corroboration because the issue had been mooted.
Practice Tip: A party wishing to challenge inventorship to add an inventor faces a high bar. First, the burden of proof is clear and convincing evidence. Second, the putative inventor must meet all three parts of the Pannu test, which includes considering the description of the invention and the scope of the claims in the patent. Litigants should consider how to develop the evidentiary record to best serve their goals in light of the burden and tests for joint inventorship.
HIP, Inc. v. Hormel Foods Corp., No. 2022-1696, 2023 WL 3184358 (Fed. Cir. May 2, 2023) (Lourie, Clevenger, Taranto)