To be valid, a U.S. patent must identify the true inventor or joint inventors.1 The willful naming of an incorrect inventive entity on a U.S. patent application, either by omitting an inventor or by erroneously including a non-inventor, constitutes grounds for invalidating any patent that issues from the application. A mistake in the naming of inventors can be corrected, but only if the mistake occurred through error and all concerned parties receive notice and an opportunity to be heard. Because the U.S. Constitution and Patent Laws allocate patents to inventors, the rights of a patentee or exclusive licensee can be clouded if less than all of the inventors assign or license their rights. Thus, it is important to pay particular attention to inventorship issues, especially when preparing to file a patent application.
A patent application must name the natural person or persons who conceived the claimed invention. Courts have recently confirmed that artificial intelligence (AI) systems cannot be named as inventors.2 An individual should be named as an inventor or joint inventor if they contributed to the conception of the invention set forth in at least one of the claims. Because inventorship is claim-dependent, it can change during prosecution of an application when a claim is amended, added, or cancelled.
Statutory Requirement to Name the Inventor (or Joint Inventors)
The Patent Laws, at Title 35 of the United States Code, set the basic requirements for inventorship. They require a patent application to include the name of the inventor for any invention claimed in the application, and that joint inventors should apply for a patent jointly.3 The Patent Laws further recognize that inventors can be joint inventors “even though (1) they did not physically work together or at the same time, (2) each did not make the same type or amount of contribution, or (3) each did not make a contribution to the subject matter of every claim of the patent.”4
Joint Inventorship Under U.S. Law
Many cases have elaborated on what constitutes joint inventorship, which one court characterized as “one of the murkiest concepts in the muddy metaphysics of patent law.”5 The cases emphasize that “conception is the touchstone of inventorship.”6 Conception is the formation in the mind of the inventor of a definite and permanent idea of the complete and operative invention, including every feature sought to be patented.7 For joint inventorship, each joint inventor need not make the same type or amount of contribution, but each must make a meaningful contribution to the invention. Joint inventorship requires some level of collaboration between co-inventors leading to the conception of the complete and operative invention claimed. As noted in the Patent Laws, the inventors need not physically work together or at the same time, however. Some amount of communication can be sufficient, even if indirect.8 By contrast, an individual who simply applies ordinary skill after the operative inventive concept has been formed in the mind of another is generally not an inventor. Activities found not to give rise to joint inventorship include: reducing an invention to practice, performing routine engineering or testing, and making contributions that are insignificant in quality when measured against the dimension of the full invention. While inventorship is a question of law decided by the court, not a jury, the cases demonstrate that joint inventorship must be determined based on the specific facts surrounding the invention.
Inventorship vs. Authorship
Inventorship is also distinct from authorship. In academic or scientific publications, authorship may be extended to supervisors, technicians, or others as a matter of custom or professional courtesy, even if they contributed little to the underlying ideas or the writing itself. Patent inventorship, however, is governed by legal standards pertaining to conception.
The Importance of Determining Inventorship Early – A Cautionary Tale
As discussed above, the omission of a true inventor (non-joinder) or the inclusion of someone who is not an inventor (misjoinder) can often be corrected to preserve the validity of a patent, provided that all parties concerned are given notice and an opportunity to be heard. Even so, the ownership rights of a joint inventor can undermine a correction of inventorship. The decision of the U.S. Court of Appeals for the Federal Circuit in Ethicon, Inc. v. U.S. Surgical Corp., 135 F.3d 1456 (Fed. Cir. 1998) illustrates this point. In Ethicon, a non-joinder error ultimately derailed the infringement claim. In the leadup to trial, the defendant, U.S. Surgical, identified an omitted joint inventor and obtained a retroactive exclusive license from him in exchange for payments contingent on U.S. Surgical prevailing in the action. The court concluded that the omitted individual qualified as a joint inventor and that the license was a valid exercise of the inventor's joint ownership rights. Inventorship was corrected upon U.S. Surgical’s motion, thereby preserving the validity of the patent. However, the omitted inventor refused to join the suit as a necessary co-plaintiff and could not be involuntarily joined because the exclusive license he granted to U.S. Surgical included the “right to sue.” As a result, Ethicon’s suit against U.S. Surgical was dismissed.
The Ethicon decision underscores the importance of carefully identifying everyone who could reasonably be deemed to have contributed to the conception of the invention claimed. Companies pursuing patent protection for inventions developed by employees or consultants should address inventorship and ownership issues early on — ideally before personnel changes occur or the invention achieves commercial success. Obtaining signed assignments from all possible inventors at an early stage can be critical. It is best not to rely on an employment policy, employee agreement, or other agreement predating the invention, as an agreement that merely states the person “will assign” inventions, or that unspecified inventions “shall be owned” by the company, is insufficient to transfer legal title to patents. Promptly securing a valid assignment at the outset of the patenting process can help avoid complications that often arise when an inventor later becomes unavailable or uncooperative.
Identifying Inventors in Provisional Patent Applications
Because provisional applications are not required to include claims, and often do not, determining inventorship can be challenging at the provisional stage. It is nevertheless a good idea to investigate inventorship while memories are fresh. The applicant should identify every individual who could possibly qualify as an inventor of the subject matter described in the provisional application, even if it might not be claimed, and obtain an assignment from all of them. Inventorship can be reevaluated after claims are prepared for a corresponding nonprovisional application. To claim the priority benefit of the provisional application, the nonprovisional application need only have one named inventor in common with the provisional application.9
Conclusion
Determining inventorship requires a careful analysis of the facts surrounding the conception of the claimed invention. Because errors in inventorship can affect patent ownership, validity, and standing to sue for infringement, it is important to evaluate inventorship early in the patent application process. Working with experienced patent counsel can help ensure inventorship is properly determined and ownership transfers are effectively documented. If you have questions about inventorship in U.S. patent applications, please reach out to Kassim Ferris or another member of Miller Nash’s intellectual property team.
1 Pannu v. Iolab Corp., 155 F.3d 1344 (Fed. Cir. 1998); Fortress Iron, LP v. Digger Specialties, Inc., 171 F.4th 1310 (Fed. Cir. 2026).
2 See, e.g., Thaler v. Vidal, 43 F.4th 1207 (Fed. Cir. 2022).
3 See 35 U.S.C. §§ 101, 111(a), 115(a), and 116(a).
4 35 U.S.C. § 116(a).
5 Meuller Brass Co. v. Reading Industries, Inc., 352 F.Supp. 1357, 1372 (E.D. Pa. 1972).
6 Burroughs Wellcome Co. v. Barr Labs., Inc., 40 F.3d 1223 (Fed. Cir. 1994).
7 Sewall v. Walters, 21 F.3d 411 (Fed. Cir. 1994).
8 See Kimberly-Clark Corp. v. Procter & Gamble Distrib. Co., Inc., 973 F.2d 911, 917 (Fed. Cir. 1992)(“there must be some element of joint behavior, such as collaboration or working under common direction, one inventor seeing a relevant report and building upon it or hearing another's suggestion at a meeting”).
9 See 35 U.S.C. § 119(e); MPEP 200.01(a).
This article is provided for informational purposes only—it does not constitute legal advice and does not create an attorney-client relationship between the firm and the reader. Readers should consult legal counsel before taking action relating to the subject matter of this article.
