A potential strategy to challenge patent validity is that the inventorship is wrong — either an actual inventor was omitted, known as a nonjoinder of inventors claim, or inventors are listed that did not contribute to the conception of the invention, known as a misjoinder of inventors claim.

This argument flows from the requirement that correct inventors must be named on a patent.[1] Challenging inventorship would therefore seem to be a viable defense to patent infringement by alleging that the patent is invalid. That was the issue in Plastipak Packaging Inc. v. Premium Waters Inc.

The U.S. District Court for the Western District of Wisconsin decided the patents were invalid due to misjoinder of inventors. On appeal, the U.S. Court of Appeals for the Federal Circuit reversed and remanded on Dec. 19. This decision highlights the difficulties of sustaining claims of misjoinder or nonjoinder of inventors as a strategy to invalidate patents.

In Plastipak, a set of 12 patents covering bottle screw caps were asserted against Premium Waters. All the patents list Richard Darr and Edward Morgan as the inventors.

Premium Waters alleged that the patents were invalid because an additional inventor, Alessandro Falzoni, was not named. Falzoni was an employee of SACMI Imola, a company that was collaborating with Plastipak in the design of bottles. At some point, the collaboration between Plastipak and SACMI ended, and Plastipak filed the patents naming only Darr and Morgan as inventors.

The district court agreed with Premium Waters and concluded that Falzoni was a joint inventor because he contributed the X dimension limitation and the discontinuous TEF limitation.[2] The court found on summary judgment that the patents were invalid due to nonjoinder of inventors.

On appeal, the Federal Circuit disagreed and found there were genuine disputes of material fact, so that a reasonable fact-finder, taking the evidence in the light most favorable to Plastipak as the nonmoving party, could reject Premium Waters' position that Falzoni is a nonjoined inventor.

Accordingly, the panel vacated the district court finding and remanded. Based on an historical analysis of attempts to invalidate patents for improper naming of inventors, this result is not surprising.

Despite the admonishments that patents have been found invalid for misnaming inventors,[3] a final holding invalidating a patent for incorrect inventorship has been very unusual.

U.S. Circuit Judge Pauline Newman collected a number of cases in the Federal Circuit where inventorship was an issue in her dissent in Ethicon Inc. v. U.S. Surgical Corp. in 1998,[4] but holdings of actual patent invalidity do not match the commonly repeated language of judges — district courts and the Federal Circuit and predecessor courts — that patents can

be invalidated for misjoinder or nonjoinder of inventors.

There appear to be no instances, at least since at least 1915, where a final decision actually invalidated a patent for misnaming inventors.[5]

An important factor in the difficulty of invalidating patents based on misnaming of inventors is that inventorship of issued patents can be corrected — the Patent Act of 1952 included Title 35 of the U.S. Code, Section 256, allowing correction of errors in inventorship without deceptive intent.[6]

Section 256 was amended in the America Invents Act to remove the deceptive intent requirement, but still allowing correction of inventorship.

While correction would seem to be a solution to claim of incorrect inventorship, patentees may not always accede to amending inventorship and would rather dispute a claim of misjoinder or nonjoinder of inventors, thus leading courts to rule on validity questions based on inventorship.

There are many reasons why patent owners wouldn't want to amend inventorship. Because inventors normally assign their rights to employers or other financial backers, adding or removing an inventor may significantly affect who can claim an ownership interest in a patent.

For example, adding an inventor may add a new owner to the patent, particularly if, as in Plastipak, the alleged unnamed inventor works for a different company than the originally named inventors. That could add another ownership entity to the patent and require compensation from the other owners.

Removing an inventor could remove an ownership interest in a patent, and the removed owner may not want to lose the benefits of patent ownership, such as a royalty stream. Also, accused infringers have no interest in preserving patent validity and will seek to have a patent invalidated as a defense to infringement. An invalid patent cannot be infringed.[7]

In Plastipak, the patent challenger was accused of infringement and therefore wanted to invalidate the patents without invoking Section 256 to preserve validity. We don't know if Plastipak sought to amend the inventorship under Section 256, but they may have been reluctant to because SACMI would have become an owner of the patent and might be entitled to compensation.[8]

Furthermore, misjoinder and nonjoinder of inventors have long been viewed as technical defects, not to be favored as objections or defenses to patent rights.[9]

As the U.S. District Court for the Eastern District of Pennsylvania said in Mueller Brass Co. v. Reading Industries Inc. in 1972:

When an infringer claims that someone is on a patent as inventor who shouldn't be, "this defense has always been regarded as technical, and is looked upon with disfavor by the courts, and clear and convincing proof is required to sustain it."[10]

U.S. Circuit Judge Alan David Lourie, in the Federal Circuit, stated in Canon Computer Systems Inc. v. Nu-Kote International Inc. in 1998 that "Incorrect inventorship is a technical defect in a patent that may be easily curable."[11]

Moreover, Donald Chisum quotes former U.S. District Judge Learned Hand in Chisum on Patents as strongly critical of the claim of misnamed inventors in 1935 stating, "courts have always regarded this defense with hostility," on the argument that inventorship isn't relevant to the public disclosure function of patents.[12]

Despite this criticism of the defense that incorrect inventorship is an argument for patent invalidity, the law is clear that correct inventors must be named on a patent.[13]

This is a very important feature of patent law, because inventorship in many cases ultimately controls who owns the patent and therefore who enjoys the benefits of the patent.

It can be a temptation to add or omit inventors to adjust the ownership of a patent to add or remove owners for business reasons without regard to the actual inventors.

For example, a financial backer of an invention could be tempted to assert an inventive interest in order to minimize or sidestep other ownership questions. If the financial backer was not an actual inventor, meaning a person who contributed to the conception of the invention,[14] then the inventors listing is incorrect, and the patent may be susceptible to an invalidity challenge.

Likewise, as in the Plastipak case, one party, Plastipak, apparently did not want to share invention with another party, Falzoni's employer. Another example could be an employer who has a falling out with an employee inventor and wants to cut that person out of the project, even though the omitted inventor made a significant contribution to the invention.

By not naming the correct inventors, the statutory requirements of inventorship are violated, putting the validity of any such patent into question. Thus, the listing of inventors has substantial implications in patent ownership and validity questions.

Courts should have an interest in preserving patent validity where possible.[15] This is the reason Congress enacted Section 256.[16] But courts also have an obligation of fairness to all stakeholders in patent disputes.

As discussed above, the bar to success in claims of misnaming inventors has been very high. Perhaps the pendulum has swung too far here.

While misjoinder or nonjoinder of inventors may theoretically be a viable statutory claim to patent invalidity, we are still waiting for a case where this claim will succeed on appeal.

Andrew H. Berks, Ph.D., is a partner at Gallet Dreyer & Berkey LLP.

The opinions expressed are those of the author(s) and do not necessarily reflect the views of their employer, its clients, or Portfolio Media Inc., or any of its or their respective affiliates. This article is for general information purposes and is not intended to be and should not be taken as legal advice.

[1] 35 USC §102 "A person shall be entitled to a patent..." if requirements of novelty and non-obviousness are met (both pre- and post-AIA), combined with §116 (joint inventors must apply for a patent jointly; similar in pre- and post-AIA).

[2] Plastipak, slip op. at 9.

[3] Judge Newman's dissent in Ethicon, Inc. v. United States Surgical Corp., 135 F.3d 1456, 1469-70 (Fed. Cir. 1998) collected a number of cases.

[4] 135 F.3d 1456, 1469-1470 (Fed. Cir. 1998).

[5] William R Thropp & Sons Co. v. De Laski & Thropp Circular Woven Tire Co, 226 F. 941, 947 (3d Cir. 1915). For other cases where the claim of incorrect inventorship failed, see inter alia, Larson v. Correct Craft, Inc., 569 F.3d 1319, 1328 (Fed. Cir. 2009); Jamesbury Corp. v. United States, 207 Ct. Cl. 516, 518 F.2d 1384, 1395, (Ct. Cl. 1975); Amax Fly Ash Corp. v. United States, 206 Ct. Cl. 756, 773, 514 F.2d 1041, 1050 (1975); Iowa State University Research Foundation, Inc. v. Sperry Rand Corp., 444 F. 2d 406, 408 (4th Cir. 1971); Hobbs v. United States, 451 F.2d 849, 865 (5th Cir. 1971); Pointer v. Six Wheel Corp., 177 F.2d 153, 158 (9th Cir. 1949); Eli Lilly & Co. v. Premo Pharm. Labs., Inc., 630 F.2d 120, 135 (3d Cir. 1980); Pannu v. Iolab Corp., 155 F.3d 1344, 1353 (Fed. Cir.

1998); Solomon v. Kimberly-Clark Corp., 216 F.3d 1372, 1381 (Fed. Cir. 2000); Egenera, Inc. v. Cisco Sys., 972 F.3d 1367, 1378 (Fed. Cir. 2020).

[6] Iowa State, 444 F.2d at 408.

[7] 35 U.S.C. §282(b).

[8] See n. 7 in Plastipak.

[9] Moy's Walker on Patents, §10.56.

[10] Mueller Brass Co. v. Reading Indus., Inc., 352 F. Supp. 1357, 1372–73 (E.D. Pa. 1972), aff'd, 487 F.2d 1395 (3d Cir. 1973) (cleaned up).

[11] Canon Computer Systems, Inc. v. Nu-Kote Int'l, Inc., 134 F.3d 1085, 1089 (Fed. Cir. 1998).

[12] 1 Chisum on Patents § 2.03(4)(a)(2020), citing Buono v. Yankee Maid Dress Corp., 77 F.2d 274, 26 USPQ 57 (2d Cir. 1935).

[13] Note 1 above.

[14] "The 'inventor,' in patent law, is the person or persons who conceived the patented invention" CR Bard, Inc. v. M3 Systems, Inc. 157 F.3d. 1340, 1352 (Fed. Cir. 1998).

[15] Phillips v. AWH Corp., 415 F.3d 1303, 1327 (Fed. Cir. 2005) ("claims should be so construed, if possible, as to sustain their validity").

[16] Iowa State, 444 F.2d at 408. (§256 permits a bona fide mistake in joining a person as inventor or in failing to join a person as an inventor to be corrected).