The U.S. Patent Office Continues to Clarify that Patent Inventorship Requires Conception, Despite Broader Language Used by Courts

  • June 4, 2024

By: Craig R. Smith

Article originally published in IEEE The Reflector, June 2024

Inventors capture our imagination by making dreams possible. Famous inventors, such as Thomas Edison and Alexander Graham Bell, not only advance the state of technology but create whole new industries based on their ideas. Conception of an invention is the key to being considered an inventor. The U.S. Patent Office has consistently emphasized that you must contribute to the conception of the invention to be deemed an inventor. Unfortunately, courts have explained the requirements for inventorship in broader terms, creating some confusion over who is entitled to be an inventor on a patent. Courts should clarify the requirements for inventorship to ensure that conception remains the touchstone for being an inventor.

When applying for a patent on an invention, the U.S. Patent Office provides specific guidance on who can be considered an inventor.

The definition for inventorship can be simply stated: “The threshold question in determining inventorship is who conceived the invention. Unless a person contributes to the conception of the invention, he is not an inventor. … Insofar as defining an inventor is concerned, reduction to practice, per se, is irrelevant. One must contribute to the conception to be an inventor.” In re Hardee, 223 USPQ 1122, 1123 (Comm’r Pat. 1984).

Manual of Patent Examining Procedure (“MPEP”) 2109.

Conception of the invention is key to inventorship. Courts have explained that “[c]onception is the ‘formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice.’” Ethicon, Inc. v. U.S. Surgical Corp., 135 F.3d 1456, 1460 (Fed. Cir. 1998) (quoting Hybritech, Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1376, 231 USPQ 81, 87 (Fed.Cir.1986)). Once an invention has been conceived, however, the steps required to reduce it to practice do not make someone an inventor.

The Patent Office and courts should define inventorship in the same way, but they do not always do so. For example, the Federal Circuit has repeatedly used broader language to describe the requirements for inventorship, creating confusion among patent practitioners and tech companies. In the Pannu case, the Federal Circuit set forth the requirements for being considered a joint inventor:

All that is required of a joint inventor is that he or she (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.

Pannu v. Iolab Corp., 155 F.3d 1344, 1351 (Fed. Cir. 1998).

The court’s requirements broaden the definition of an inventor to a person who contributes to either the conception or reduction to practice of the invention. In other words, conception alone is not required to be considered an inventor. If applied as written, the court’s statement would create a new standard, allowing an inventor to contribute only to the reduction to practice of the invention. This broader standard would conflict with the court’s own precedent on inventorship and the Patent Office’s guidance.

The Pannu court cited two cases in support of its inventorship requirements: Fina Oil and Ethicon. Fina Oil & Chem. Co. v. Ewen, 123 F.3d 1466, 1473 (Fed.Cir.1997) and Ethicon, Inc. v. United States Surgical Corp., 135 F.3d 1456, 1460 (Fed.Cir.1998). Neither one of these cases supports the proposition that “reduction to practice” alone is sufficient to be considered an inventor.

In Fina, the Federal Circuit confirmed that “[c]onception is the touchstone to determining inventorship.” Fina, 123 F.3d at 1473. Likewise in Ethicon, the court held that conception is the key issue and “one does not qualify as a joint inventor by merely assisting the actual inventor after conception of the claimed invention.” Ethicon, 135 F.3d at 1460. Thus, reducing the invention to practice does not make a person an inventor: “one of ordinary skill in the art who simply reduced the inventor’s idea to practice is not necessarily a joint inventor.” Id.

Nevertheless, after Pannu, the Federal Circuit and district courts have continued to cite the same Pannu factors for determining inventorship. For example, last year the Federal Circuit again repeated the Pannu factors that “a joint inventor must contribute in a significant manner to the conception or reduction to practice of the invention, make a contribution to the invention that is not insignificant, and do more than explain well known concepts or the current state of the art.” HIP, Inc. v. Hormel Foods Corp., 66 F.4th 1346, 1353 (Fed. Cir. 2023); see also Plastipak Packaging, Inc. v. Premium Waters, Inc., 55 F.4th 1332, 1340 (Fed. Cir. 2022); In re VerHoef, 888 F.3d 1362, 1366 (Fed. Cir. 2018); Audionics Sys., Inc. v. AAMP of Fla., Inc., No. CV1210763MMMJEMX, 2015 WL 12712288, at *47 (C.D. Cal. July 10, 2015); Illinois Tool Works, Inc. v. MOC Prod. Co., 856 F. Supp. 2d 1156, 1185 (S.D. Cal. 2012).

The Patent Office has taken note of the court’s broader language and explained that the Patent Office’s test for inventorship has not changed. A recent Patent Office paper on inventorship took pains to clarify why the Federal Circuit’s Pannu factors do not change its requirement for conception of the invention:

While these [Pannu] factors do refer to reduction to practice, applicants are reminded that the main inquiry is who conceived of the invention. Reduction to practice, per se, is generally irrelevant to this inquiry. MPEP 2109(II) (citing Fiers v. Revel, 984 F.2d 1164, 1168 (Fed. Cir. 1993)). The mention of reduction to practice in the Pannu factors is an acknowledgement of the simultaneous conception and reduction to practice doctrine used in unpredictable technologies. See, e.g., Amgen, Inc. v. Chugai Pharm. Co., 927 F.2d 1200, 1206 (Fed. Cir. 1991). The Pannu factors are not a basis to conclude that reduction to practice, alone, is sufficient to demonstrate inventorship.

Patent & Trademark Office: “Inventorship Guidance for AI-assisted Inventions,” page 13, footnote 32.

The Patent Office’s guidance makes plain that conception alone remains the critical issue for inventorship. Reduction to practice is generally irrelevant and cannot, on its own, be sufficient to show inventorship.

The court’s confusing inventorship language may be the result of unique cases where conception of the invention required reduction to practice. “In some instances, an inventor is unable to establish a conception until he has reduced the invention to practice through a successful experiment. This situation results in a simultaneous conception and reduction to practice.” Amgen, Inc. v. Chugai Pharm. Co., 927 F.2d 1200, 1206 (Fed. Cir. 1991).

Simultaneous conception and reduction to practice may occur in unpredictable scientific fields, such as biotechnology. For instance, the conception of a specific DNA sequence may not occur until it has been reduced to practice. “We hold that when an inventor is unable to envision the detailed constitution of a gene so as to distinguish it from other materials, as well as a method for obtaining it, conception has not been achieved until reduction to practice has occurred, i.e., until after the gene has been isolated.” Amgen, 927 F.2d at 1206; see also Fiers v. Revel, 984 F.2d 1164, 1169 (Fed. Cir. 1993).

The holdings in Amgen and similar cases do not support the broader definition of an inventor set forth in Pannu. Amgen recognizes that the conception of some inventions requires reduction to practice. In other words, “conception is not complete if the subsequent course of experimentation, especially experimental failures, reveals uncertainty that so undermines the specificity of the inventor’s idea that it is not yet a definite and permanent reflection of the complete invention as it will be used in practice.” Burroughs Wellcome Co. v. Barr Lab’ys, Inc., 40 F.3d 1223, 1229 (Fed. Cir. 1994). In these unique cases, conception of the invention was not complete until reduction to practice occurred.

Cases involving simultaneous conception and reduction to practice do not change the requirement that inventorship is based on conception. Once an invention has been conceived, reduction to practice is irrelevant to inventorship. In short, reduction to practice alone is insufficient to satisfy the requirement for inventorship.

Moving forward, courts should be more precise in describing the requirements for inventorship. The first requirement for inventorship under the Pannu test should read: “All that is required of a joint inventor is that he or she (1) contribute in some significant manner to the conception of the invention, …” This language is consistent with the court’s prior precedent and the Patent Office’s guidance on inventorship.



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