United States: When Do Collaborators Become Coinventors?

Every invention begins with an inventor, someone who birthed an idea, solved a problem, or refined an existing idea to create something new. In the United States, inventors or their assignees can apply for a U.S. patent to protect their intellectual property. But the question of who qualifies as an inventor under U.S. patent law is not always straightforward, with the modern research environment often involving collaboration among scientists. Depending on their contributions, collaborators may become joint inventors who hold equal rights in the patented invention and must be named on the patent.

A recent decision by the U.S. Court of Appeals for the Federal Circuit reminds both patent practitioners and scientific collaborators of possible repercussions when an applicant for a U.S. patent fails to correctly identify all joint inventors. In that case, a dog owner was unable to secure a patent to a dog mobility device because the U.S. Patent and Trademark Office (PTO) determined that he did not identify his coinventor on the application. On appeal, the Federal Circuit affirmed. In re VerHoef, 888 F.3d 1362, 1368 (Fed. Cir. 2018). A full understanding of the court’s reasoning requires knowledge about joint inventorship, which has been described as "one of the muddiest concepts" of U.S. patent law. Mueller Brass Co. v. Reading Indus., Inc., 352 F. Supp. 1357, 1372 (E.D. Pa. 1972), aff’d, 487 F.2d 1395 (3d Cir. 1973).

Requirements of Joint Inventorship

A. Collaboration or Concerted Effort

Joint inventorship can arise only when there is "collaboration or concerted effort . . . [,] that is, when the inventors have some open line of communication during or in temporal proximity to their inventive efforts." Eli Lilly & Co. v. Aradigm Corp., 376 F.3d 1352, 1359 (Fed. Cir. 2004). Scientists that routinely work in groups and exchange ideas may be said to collaborate. The requisite collaboration can be remote, as joint inventors do not need to work in the same physical location or at the same time. 35 U.S.C. § 116(a).

For example, the Federal Circuit in 1992 held that the U.S. District Court for the Western District of Washington correctly determined that a scientist was the sole inventor on a patent related to disposable baby diapers because the alleged coinventor knew nothing of the scientist’s work and contributed nothing to it. Kimberly-Clark Corp. v. Procter & Gamble Distrib. Co., 973 F.2d 911, 917 (Fed. Cir. 1992). On the other hand, the U.S. District Court for the District of Connecticut determined in a different case that three engineers who regularly met, interacted, and exchanged ideas were joint inventors on a patent related to an anvil groove design. U.S. Surgical Corp. v. Hosp. Prods. Int’l Pty. Ltd., 701 F. Supp. 314, 340 (D. Conn. 1988).

B. Contribution to Conception

Although the Federal Circuit has indicated that a joint inventor may "contribute . . . to the conception or reduction to practice of the invention," In re VerHoef, 888 F.3d at 1366 (emphasis added) (citation omitted), it has also indicated that "each joint inventor must generally contribute to the conception of the invention," Ethicon, Inc. v. U.S. Surgical Corp., 135 F.3d 1456, 1460 (Fed. Cir. 1998) (citation omitted). "Conception is the touchstone of invention" and requires "a definite and permanent idea of an operative invention, including every feature of the subject matter sought to be patented." In re VerHoef, 888 F.3d at 1366 (citations omitted). "An idea is definite and permanent when the inventor has a specific, settled idea, a particular solution to the problem at hand, not just a general goal or research plan." Id. (citation omitted).

Joint inventors together must conceive of every feature of the claimed invention such that a person of ordinary skill in the art could construct the invention without unduly extensive research or experimentation. Sewall v. Walters, 21 F.3d 411, 415 (Fed. Cir. 1994). But each joint inventor need not equally contribute. In re Verhoef, 888 F.3d at 1366 (citing, e.g., 35 U.S.C. § 116(a)). A collaborator who contributes to the conception of just a single claim may be a joint inventor under U.S. patent law. Ethicon, 135 F.3d at 1460.

For example, in 2012, the Federal Circuit affirmed a determination by the U.S. District Court for the Northern District of Ohio that a scientist’s development of a method of making the genus of claimed chemical compounds was "enough of a contribution to conception to pass the threshold required for joint inventorship." Falana v. Kent State Univ., 669 F.3d 1349, 1359 (Fed. Cir. 2012). "Where the method requires more than the exercise of ordinary skill, . . . the discovery of that method is as much a contribution to the compound as the discovery of the compound itself.’’ Id. at 1358.

C. Significant Contribution

To be a joint inventor, a collaborator must "make a contribution to the claimed invention that is not insignificant in quality, when . . . measured against the dimension of the full invention," and "do more than merely explain to the real inventors well-known concepts and/or the current state of the art." In re Verhoef, 888 F.3d at 1366 (citation omitted). For example, the Federal Circuit in 1998 affirmed a determination by the U.S. District Court for the District of Connecticut that an electronics technician was a joint inventor with a medical doctor on a patent for a surgical instrument used in endoscopic surgeries, based on the technician’s conception of several features of the instrument. Ethicon, 135 F.3d at 1462-64.

On the contrary, the Federal Circuit in a different case in 2006 affirmed summary judgment by the U.S. District Court for the Southern District of New York that a medical student was not a coinventor on a patent related to the use of prostaglandins to treat glaucoma. Stern v. Trs. of Columbia Univ., 434 F.3d 1375, 1376 (Fed. Cir. 2006). The court determined that the medical student "simply carried out an experiment previously done by [the inventor] on different animals—animals that [the inventor] had already determined would be good models for prostaglandins research." Id. at 1378. The court found that this contribution was "insufficient to support a claim of co-inventorship." Id.

The Federal Circuit also determined that an alleged coinventor’s contribution was insufficient in a different case in 2009. In that case, the Federal Circuit reversed summary judgment by the U.S. District Court for the Eastern District of Michigan that dismissed a complaint for infringement of a patent related to introducing massage functionality to an automobile seat based on nonjoinder of an alleged coinventor. Nartron Corp. v. Schukra U.S.A., Inc., 558 F.3d 1352, 1353-54 (Fed. Cir. 2009). The Federal Circuit determined that the alleged coinventor’s "contribution of the extender [was] insignificant when measured against the full dimension of the invention . . . , not just because it was in the prior art, but because it was part of existing automobile seats, and therefore including it as part of the claimed invention was merely the basic exercise of ordinary skill in the art." Id. at 1357.

Possible Repercussions of Incorrectly Naming Inventors

A. Rejection of Claims During Prosecution

U.S. patent applications filed before March 16, 2013, are generally subject to pre-America Invents Act (AIA) 35 U.S.C. § 102(f). 35 U.S.C. § 100 (note) (AIA First Inventor to File Provisions). Under pre-AIA § 102(f), a person cannot obtain a patent if "he did not himself invent the subject matter sought to be patented." 35 U.S.C. § 102(f) (pre-AIA).

The PTO has rejected claims under pre-AIA § 102(f) where an application does not correctly name all inventors. For example, in 2018, the Federal Circuit affirmed the PTO’s rejection of claims to a mobile dog device under pre-AIA § 102(f) because the dog owner applicant did not name his coinventor on the application. In re VerHoef, 888 F.3d at 1367-68. After his dog had surgery, the dog owner worked on developing a dog mobility harness. He discussed the idea with the dog’s veterinarian, who suggested using a figure-eight loop around the dog’s toes and leg. Although the dog owner initially filed for a patent listing the veterinarian as his coinventor, he later withdrew that application and refiled a new one listing himself as sole inventor. The PTO rejected the dog owner’s second application under § 102(f), reasoning that the dog owner did not conceive of every claim. On appeal, the Federal Circuit affirmed because the veterinarian "contributed the idea of the figure eight loop[,] . . . an essential feature of the invention not insignificant in quality or well-known in the art," and was therefore a joint inventor. Id. at 1366-67.

Although the AIA version of § 102 does not include a subsection (f) or contain the same language as pre-AIA § 102(f), the PTO has indicated it will continue to reject errors of inventorship under 35 U.S.C. § 101 and § 115. Manual of Patent Examining Procedure (MPEP) § 2157 (9th ed. Jan. 2018).

B. Motions by Omitted Inventors to Correct Inventorship

The PTO may correct inventorship when an inventor is not named on an issued patent or a person is named in error. 35 U.S.C. § 256(a). If inventorship can be corrected, then the error will not render the patent invalid. Id. § 256(b).

A court may order correction of inventorship, but an omitted inventor who moves for correction must meet a "heavy burden." Eli Lilly, 376 F.3d at 1358. Inventorship on issued patents is presumed to be correct, and a challenger must prove its case by "clear and convincing evidence" and provide corroborating evidence. Id. For example, in 2016, the Federal Circuit affirmed an order by the U.S. District Court for the Southern District of Texas to correct inventorship based on clear and convincing evidence that two joint inventors were omitted. Vapor Point LLC v. Moorhead, 832 F.3d 1343, 1349 (Fed. Cir. 2016), cert. denied sub nom. Nanovapor Fuels Grp., Inc. v. Vapor Point, LLC, 137 S. Ct. 1121 (2017).

C. Allegations of Inequitable Conduct

Patent applicants who intentionally falsify inventorship to the PTO risk invalidation of any issued patent based on inequitable conduct. "[I]nequitable conduct renders an entire patent (or even a patent family) unenforceable . . . ." Therasense, Inc. v. Becton, Dickinson & Co., 649 F.3d 1276, 1292 (Fed. Cir. 2011) (en banc). "To prevail on a claim of inequitable conduct, the accused infringer must prove that the patentee acted with the specific intent to deceive the PTO." Id. at 1290. Accused infringers may allege inequitable conduct as a defense in patent litigations.

For example, in 2000, the Federal Circuit found that the U.S. District Court for the District of Massachusetts did not abuse its discretion in holding the asserted patents unenforceable for inequitable conduct based on incorrect inventorship. PerSeptive Biosys., Inc. v. Pharmacia Biotech, Inc., 225 F.3d 1315, 1322-23 (Fed. Cir. 2000). The Federal Circuit found no clear error in the district court’s finding that there were "at least five specific instances of intentional falsehoods, misrepresentations, and omissions" directed to the material issue of inventorship. Id. at 1322.

D. Dismissal of Patent Infringement Suit for Nonjoinder

Patent holders seeking to enforce their patent rights against an accused infringer might find their suits dismissed for nonjoinder if a court determines that the patent does not name all joint inventors. "[I]n the context of joint inventorship, each co-inventor presumptively owns a pro rata undivided interest in the entire patent, no matter what their respective contributions." Ethicon, 135 F.3d at 1465 (footnote omitted). "[A] joint inventor as to even one claim enjoys a presumption of ownership in the entire patent." Id. at 1466. Each joint owner of a patent has certain rights, including the right to "make, use, offer to sell, or sell the patented invention . . . without the consent of and without accounting to the other owners." 35 U.S.C. § 262. Additionally, "as a matter of substantive patent law, all co-owners must ordinarily consent to join as plaintiffs in an infringement suit. Consequently, 'one co-owner has the right to impede the other co-owner’s ability to sue infringers by refusing to voluntarily join in such a suit.'" Ethicon, 135 F.3d at 1468 (footnote omitted) (citation omitted); see also  35 U.S.C. § 262.

In Ethicon, a patent holder sued another company for infringement of its patent directed to a surgical tool. 135 F.3d at 1459. While litigation was pending, the accused infringer became aware of a potentially omitted joint inventor and received a retroactive license to the patent from that individual. The individual then intervened in the suit and sought correction of the patent’s inventorship. The district court found that the individual was a joint inventor, granted the defendant’s motion to correct inventorship under 35 U.S.C. § 256, and dismissed the case. The Federal Circuit affirmed, reasoning that the complaint lacked the participation of a patent coowner because the omitted joint inventor "did not consent" to the infringement suit and could not consent "due to his grant of an exclusive license with its accompanying 'right to sue.'" Id. at 1468.


Whether scientists are joint inventors under U.S. patent law is a fact-specific question requiring collaboration, contribution to the conception of the invention, and a significant contribution to the invention. Although errors in inventorship may be corrected in some circumstances, applicants should take measures to correctly identify all inventors during prosecution to avoid possible rejection of their claims, later motions by alleged omitted inventors, allegations of inequitable conduct, or dismissal of later patent infringement suits based on nonjoinder.

Originally published in BNA's Patent, Trademark & Copyright Journal

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