Inventorship 101: Who are Inventors and Joint Inventors?

Inventorship 101: Inventors, Joint Inventors and Co-Inventors

Inventorship is an important concept in patent law. Inventors are those who contribute the ingenuity necessary to create an invention. It is, however, possible for an invention to be the work of two or more joint inventors, sometimes referred to as co-inventors.

Inventorship is one of the most fundamental concepts in patent law. Of course, fundamental does not mean easy or uncomplicated.

Patents are granted to inventors, which is easy enough to say but not always as informative as the patent laws presume it to be. In fact, pretty much everyone comes to patent law for the first time with an erroneous belief about what it means to be an inventor.

Ask yourself these two true/false questions:

  1. An inventor is someone who came up with the idea for the invention?
  2. An inventor is someone who diligently works on making the invention?

Okay, those were trick true/false questions. Technically in a true/false environment the answer to each is false, because there are circumstances when a person who works on making the invention is not an inventor, and the same is also true for the person who came up with the idea. The better answer to each question is maybe, but maybe not.

Inventorship: The Conception Requirement

Unfortunately, many people will have great ideas, but will not be able to put that idea into a package appropriate for a patent because there is no invention, only a concept. To be sure, the idea is the all critical first step in the invention process, but an idea is not enough in and of itself. After you come up with the idea or concept you now need to put together a game plan on how to carry that idea through to fruition. The idea plus a game plan together form what the law calls conception.

“Conception 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.” Hybritech, Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1376 (Fed. Cir. 1986). In other words, conception requires mental dominion over the invention. This means inventors control the intellectual pursuit and contribute the ingenuity necessary to create an invention.


Making the Invention

The United States Court of Appeals for the Federal Circuit has explained the requirement for having an invention in this way:

“Making the invention requires conception and reduction to practice. While conception is the formation, in the mind of the inventor, of a definite and permanent idea of a complete and operative invention, reduction to practice requires that the claimed invention work for its intended purpose.”

Solvay S.A. v. Honeywell International, 742 F.3d 998, 1000 (2014).

To complicate matters, when the Federal Circuit refers to “making the invention,” which adds a wrinkle that again will lead the novice in the industry to come to the wrong conclusion. The date of an invention relates to the conception of the invention. In the regard, in order to have an invention you do not actually need to have a reduction of practice. The invention is birthed with conception. Invention is finalized with reduction to practice.

To complicate matters even further, there are two types of reduction to practice. The first is called actual reduction to practice, which actually means what the name implies. You have an actual reduction to practice if you have a working prototype, or if your invention is a process, if you have successfully performed the process. The second type of reduction to practice is called a constructive reduction to practice, the meaning of which is not perfectly apparent from the name. As the Federal Circuit has explained, “[t]he filing of a patent application serves as conception and constructive reduction to practice of the subject matter described in the application.” Hyatt v. Boone, 146 F.3d 1348, 1352 (Fed. Cir. 1998). The concept of constructive reduction to practice was relevant in some cases when U.S. patent laws were first to invent.

Invention starts with conception and ends with a reduction to practice. Easy enough to say but not particularly enlightening.

In order for one to be considered an inventor they must contribute to conception (i.e., the mental aspect of inventing). Those who only contribute to reduction to practice are not considered inventors, no matter how much time and energy they put into the project. This is why a patent attorney who writes up and files a patent application describing an invention is not ordinarily considered an inventor – at best they only took part in a constructive reduction (i.e., explaining the invention in a patent application). It is also why lab technicians who are merely following the directions of a superior are not considered inventors either.

Joint Inventors (aka Co-Inventors)

Taking next steps, it is possible for a patented invention to be the work of two or more joint inventors. See 35 U.S.C. § 116. Because “[c]onception is the touchstone of inventorship,” each joint inventor must contribute to the conception of the invention. Burroughs Wellcome Co. v. Barr Lab., Inc., 40 F.3d 1223, 1227-28 (Fed. Cir.1994). There is no requirement that the conception be of equal magnitude though. Indeed, it is not necessary for each inventor to contribute conception to all of the patent claims filed in order to be joint inventor. It is enough for one to contribute conception to a single claim in order to be considered a joint inventor. See SmithKline Diagnostics, Inc. v. Helena Lab. Corp., 859 F.2d 878, 888 (Fed. Cir. 1988). Thus, if one contributes to the conception of something – indeed anything – that winds up being claimed in a patent application they are joint inventors (or co-inventors as they are sometimes referred to).

On the other hand, one does not qualify as a joint inventor by merely assisting the actual inventor after conception of the claimed invention. In Sewall v. Walters, 21 F.3d 411 (1994), the Federal Circuit explained that the hardware design employed by Sewall amounted to nothing more than and was in fact dictated by the specifications provided by Walters. Therefore, Walters was the inventor (i.e., conceiver) and Sewall was simply a reducer to practice, and not an inventor, or joint inventor in this case. See also Shatterproof Glass Corp. v. Libbey-Owens Ford Co., 758 F.2d 613, 624 (Fed. Cir. 1985) (“An inventor ‘may use the services, ideas and aid of others in the process of perfecting his invention without losing his right to a patent.'”) Thus, one who simply provides the inventor with well-known principles or explains the state of the art without ever having “a firm and definite idea” of the claimed combination as a whole does not qualify as a joint inventor. See Hess v. Advanced Cardiovascular Systems, Inc., 106 F.3d 976, 981 (Fed. Cir. 1997).


A Caution on Joint Inventors

The reality that one who contributes conception to only a single patent claim is a joint inventor is critical for inventors to understand. This is because absent some agreement on ownership of invention rights each joint inventor will own 100% of any patent that issues. Furthermore, there is no right to an accounting between join inventors, which means a joint inventor can license or sell their rights without the permission of the other, or requirement that they share in any proceeds.

For example, Jack and Jill are co-inventors. Jill is the one who came up with the idea, which matured into a conception, and worked diligently to reduce it to practice. However, Jill brought in Jack to help with one aspect of the invention. Jack contributed conception to that one aspect, and Jack’s contribution was valuable enough to include in one (and only one) of the patent claims filed. This makes Jack and Jill co-inventors.

Let’s assume the patent issues and Jack’s contribution remains in one (and only one) of the patent claims that issues. Jack and Jill are co-inventors and both own 100% of the rights in the patent. That means that Jack owns rights to all of the claims even though he only contributed to a single claim. Jack could license the patent for $1,000,000 and owe Jill nothing. This has always seemed unfair to me, but it is what the law allows.

So, what should Jill have done? She should have entered into an agreement with Jack to have him assign any rights and interest he may have in the patent to her in exchange for something of value. For many inventors this will be in exchange for payment of some kind, as in the case where you hire a design firm or engineer to assist with aspects of the invention. An agreement between Jack and Jill would have work to prevent a problem arising should Jack think he is an inventor while Jill believe he did not contribute any conception.

If Jack and Jill were going to be partners in a business enterprise, they could have also formed a company, and both assigned their invention and patent rights to the company. This has advantages because ownership of the company can be specifically defined in the corporation documents. So, Jill could own 99% of the company to Jack’s 1% of the company. If Jack assigned his rights to the company the company would own 100% of the patent, and Jack would be unable to license or assign rights because he wouldn’t possess any right on his own.

The Jack and Jill example shows why it is worthwhile to consult an attorney if there is a joint inventor scenario. It is always easier to address the issue on the front end before an invention becomes valuable. Once real money is involved these situations have a tendency to go sideways very quickly.

Deciding who is and who is not an inventor is trickier than most imagine. It isn’t exactly brain surgery, and can be done with a definitively correct answer reached. What makes it tricky is many mistakenly believe that working to reduce an invention to practice makes them an inventor.


Let’s return to the two true/false questions asked above:

  1. An inventor is someone who came up with the idea for the invention?
  2. An inventor is someone who diligently works on making the invention?

The answer to question 1 is, yes, if and only if the person who came up with the idea contributed conception. The idea in and of itself is not enough. After all, having an idea that it would be wonderful to travel back in time does not make one an inventor of a time machine.

The answer to question 2 is, yes, if and only if the person who diligently worked on making the invention (i.e., reducing the invention to practice) actually contributed conception to at least one of the patent claims.

Happy inventing!


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Join the Discussion

14 comments so far.

  • [Avatar for Anon]
    March 13, 2018 12:03 pm

    Joe Friday,

    I think that you are misstating things (and what you misstate can – and will – be misused by people of various ilk who have a bent against patents).

    No one “claims things which [they] did not invent.”

    They may have – within their claim – elements that they did not invent.

    This is not a semantic nit.

    The invention is the claimed invention – as a whole.

    Where this intersects our current discussion though is a bit more nuanced, as we are starting to intermingle overlapping claim elements (and the proper attribution of those claim elements) and the differences between live (active prosecution) claims – each of which it should be understood that stand as a whole.

    To the fact that some claim elements are not ascribed inventive contribution, such would be an [obvious] fact.

    I suppose it comes down to a rather intensive fact pattern in that each and every claim – as a whole – has to be viewed both as what is a meaningful invention (as per the whole of the claim) and who contributed to that “whole of the claim” in a “joint inventor” sense.

    The “single mind” of a true single inventor does NOT translate well to the collection of contributors, due in no small part to the fact that for such a group, there need not be A “single mind” that would have at once integrated all of the individual contributions into that important “claim as a whole.”

    When one recognizes this fragmentation and lack of symmetry, one may become “bogged down” in the attempt to properly credit the collection of contributors, and your point then of not crediting ALL contributors – due to various conditions (e.g., some elements of contribution simply being “known” by all). What then separates the contributors from the shoulders of those whom the contributors are building upon?

    The pragmatic (albeit perhaps not entirely satisfactory) answer is: those members who (more or less) are traceable to the team effort.

  • [Avatar for Joe Friday]
    Joe Friday
    March 13, 2018 09:23 am

    Anon, I agree. But, the issue is, when I claim an improvement to an automobile, I do not give credit to Henry Ford for the first part of the claim where I claim the internal combustion engine, the four wheels, and the transmission.

    I may not be explaining it completely enough because I am too lazy to write the multiple paragraphs it would take, but, I think we all claim things which we did not invent. Photocopier clients do not give credit to the first person who invented the image transfer rollers, computer clients do not name as an inventor the first person who created the nontransient memory, etc. Do those examples make the point (question) I was setting forth more (asking) understandable? In each case, something becomes old enough/well known enough, that we no longer name the co-inventor of what is claimed.

  • [Avatar for Anon]
    March 12, 2018 01:50 pm

    Joe Friday,

    You appear to be on dangerous ground.

    It is NOT a matter of “old enough.”
    Is IS a matter of what you are claiming.

    If your current claims being prosecuted overlap, then not only will you (likely) run into the problem of proper attribution, you may also be running into the problem of not properly providing IDS information that reflect the criss-crossing claims.

    One of the things that the AIA (possibly) did right was to reduce the penalty for (inadvertent) mis-naming of inventors. But even given that, your post cause me to pause greatly and wonder how deep your troubles may run.

    I am presuming that “Joe Friday” is a pseudonym – and your post reflects another great benefit for anonymous or pseudonymous posting. Had you used your real name, and you were internal counsel to a company, your divulging of a possible questionable practice may have caused some considerable (albeit at this point potential) harm to your employer.

  • [Avatar for Benny]
    March 12, 2018 12:25 pm

    Just guessing here, but I would think that if any of the listed inventors can’t adequetely explain the invention after reading the patent specification, then the application is not enabling.

  • [Avatar for Gene]
    March 12, 2018 12:11 pm

    here’s a situation i have not been able to satisfactorily address: boss man program manager tells a first subordinate to write up (program) a subroutine that does #1, tells a second subordinate to program a function that does # 2, and so on. boss man finds out later that the subordinates successfully tested and debugged the combination of subroutines and functions, so he decides to file a patent application on it. patent attorney asks the boss man “what is the algorithm to accomplish #1?” to which boss man says “i don’t know, the first subordinate wrote it”. same situation with #2, and so on. so patent attorney asks subordinates about the algorithms which they explain adequately, but none of them know what the overall program does or the overall algorithm.

    can someone be an inventor without being able to explain how a software invention works? if so, can someone be an inventor if s/he needs to have the overall workings explained to them? such as the subordinates explaining, eventually (after filing the patent application?), to the boss man how they accomplished their programming. i tend to agree with the latter, but am not sure.

    p.s. this is not as infrequent an occurrence as you might expect.

  • [Avatar for Gene]
    March 12, 2018 11:55 am

    “Thus, if one contributes to the conception of something – indeed anything – that winds up being claimed in a patent application they are joint inventors”

    –not if the “contribution to the conception” is obvious.

  • [Avatar for Joe Friday]
    Joe Friday
    March 12, 2018 09:43 am

    We dealt with one issue at a corporation where I was an in house counsel, and I don’t think we ever came to satisfactory conclusion. It has to deal with when does something become “old enough” that you no longer name a person as a co-inventor.

    Say, for example, I work at John Deere making lawnmowers.

    If Alice makes an improvement 1, and Ben makes an improvement 2, and the claims recite both, then both are co-inventors (easy enough, I think).

    What if Alice makes 1, and files her application, and Ben hears about 1 and adds 2. Ben files his application. Is Alice a co-inventor? Does it matter if he hears about it from Alice? Does it matter is Alice and Ben made 1, and then Ben alone made 2? Does it matter if Alice’s improvement is 1 month old, 6 months old, 1 year old, ten years old?

    I haven’t written out all the possible variations of facts, but I think (hope) the readers can understand what I am getting at. We (collectively) file applications for improvements all the time, but we do not consider former inventors co-inventors when the underlying, improved invention is old enough.

  • [Avatar for Anon]
    March 11, 2018 08:51 am


    A dangerous practice, given that lying on an oath of inventorship is fraud on the Office.

  • [Avatar for Benny]
    March 11, 2018 01:28 am

    Real world:
    The first named inventor is the CTO because:
    – the CTO approved the budget for the project
    – the CTO wants another patent on the resume
    – the CTO gets to call the shots
    – who is going to argue the point ?
    Probably not universal practice, but I’ve seen it often enough.

  • [Avatar for Paul Morgan]
    Paul Morgan
    March 10, 2018 12:43 pm

    P.S. If only one or two dependent claims of an application have a joint inventor there are situations in which filing those claims in a separate application may be advisable.

  • [Avatar for Paul Morgan]
    Paul Morgan
    March 10, 2018 12:38 pm

    Gene, congratulations for an excellent, well written, short article on what is an “invention” and what is “joint invention.” As you noted, they are frequently misunderstood.
    As to “actual reduction to practice”, all new applications are under the AIA and what now counts is achieving actual reduction to practice by means of a “constructive reduction to practice” which means having a 112-adequate exemplary specification description of how to make and use the claimed invention.

  • [Avatar for Night Writer]
    Night Writer
    March 10, 2018 09:45 am

    I agree Anon that the mental steps doctrine is part of the anti-patent crowd’s quiver.

    You see this strongly in Taranto who tried to hold that any process on a computer that simulates a human mental process is per se obvious (he did so hold but it was non- precedential.) (In Europe, they said it wasn’t even worth trying to figure out how the human mind works because we know so little. And, yet Taranto is saying automating what we know so little about is per se obvious. Plus, 80 percent of Ph.D.’s in cognitive science are programs to try to automate human thought processes.)

    In Deener, a human body could perform the steps of the method of refining grain.

    I think too that attacking the mental steps doctrine may be a good first step as it illustrates all the points. Anyway, just shameful that a circuit court judge would make such a holding. The CAFC is filled with Google appointed filth.

  • [Avatar for Anon]
    March 10, 2018 06:53 am

    I agree with Night Writer – to a certain extent.

    I see the issue that Night Writer points to, but caution that many will not appreciate the level or context of the physics involved.

    Criminy, we cannot even get past the level that man can alter and manufacture waves (See In re Nuitjen for controlling law that is simply anti-factual).

    Also, I would prefer that the aim to which Night Writer wants to express the physicality of information (and thus, by default, the aspect that processing of information is necessarily an aspect of reality – as opposed to magic or witchcraft), be handled in a different manner.

    I believe that while the point Night Writer aspires to is a true capture of reality, that he point nonetheless obscures a distinction which remains critical to patent law – and a point that sees every bit as much nonsense and dissembling and obfuscation.

    That point centers around the patent doctrine of Mental Steps.

    The Mental Steps doctrine rose, had its heyday, and then fell into more or less oblivion.

    ALL of the anti-software and much of the anti-business method claptrap out there would be eviscerated if all parties joining the dialogue understood why the Mental Steps doctrine had its demise.

    So, it is not only the “magic” angle, not only the “witchcraft” angle that is present and that needs to be debunked, but it is also how those angles are portrayed on the foundation of a decrepit, built of sand, attempted reanimation of the Mental Steps doctrine that undergirds the anti-software position.

    Not only is the “thinking” of software somehow “magic” to the machine, but the machine and software are being equated to a real person and the sanctity that a real person’s though processes may inure under other areas of law.

    Even if Night Writer is successful in removing the elements of “magic” and “witchcraft” (an important task without a doubt), the battle would not be won. The necessary adjunct remains the realization that machines – no matter how constructed, no matter how configured, no matter how manufactured, remain machines and simply are not humans, simply do not actually think – as that term applies to humans, and do NOT incur any of the legal protections that a human’s thinking may incur.

    Both steps are necessary.

    The debunking and killing the zombie of the reanimated Mental Steps doctrine is a step that may be easier to accomplish than the elevated understanding of physics that Night Writer’s step will entail.

    Dispatching the zombie would also remove arguments that lead to that need for a higher level of physics understanding, perhaps lessening the need to take that larger step.

    Finally, as noted elsewhere, the expose on the Mental Steps doctrine would best come from academia or another source more ensconced with anti-patent sentiment. I add this last part, because only too often the anti-patentists will not engage on the merits, but instead look at WHO is saying something rather than WHAT is being said. A proper and detailed explication of the rise and fall of the Mental Steps doctrine from a source more aligned with anti-patentists has a better chance of actually being engaged on the merits.

  • [Avatar for Night Writer]
    Night Writer
    March 10, 2018 04:20 am

    OT, but Gene you should consider more articles that discuss information.

    >information is physical

    A lot of the 101 nonsense acts as if information is some magical thing and thought is performed by our spirit.

    Reality: information processing is a physical process just like refining grain in Deener. Reality it takes time, space, and energy to process information.

    Anyway, about 90 percent of Alice and the 101 nonsense is based on mis-characterizing information processing.