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Joint Inventorship of Patented Inventions

In a utility or nonprovisional patent application, inventorship is based on the conception of the invention. "Invention" is a specific legal term synonymous with the claims of the application or issued patent. Each and every claim, whether it is an independent or dependent claim, defines a separate invention under U.S. patent law. A patented invention may be the work of two or more joint inventors so long as each joint inventor contributed, in some significant matter, to the conception of the invention as recited in at least one claim of the application. A co-inventor need not make a contribution to every claim of a patent - a contribution to one claim is sufficient. Thus, the critical question for joint conception is who conceived, as that term is used in the patent law, the subject matter of the claims at issue.

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 thereafter to be applied in practice. Generally, an idea is sufficiently definite and permanent when only ordinary skill would be necessary to reduce the invention to practice, without extensive research or undue experimentation.

In order to prove joint inventorship, the claimant must have contributed in a significant manner to the invention's conception or reduction to practice, and not merely suggested an idea of a result to be accomplished or explained well-known concepts, or simply stated the current state of the art in the relevant technical field. An individual must make a contribution to the conception of the claimed invention that is not insignificant in quality, when that contribution is measured against the dimension of the full invention.

To be named as a co-inventor in a provisional patent application, each inventor must have made a contribution, individually or jointly, to the subject matter disclosed in the provisional application. This should be compared to a nonprovisional patent application discussed above where each inventor must have made a contribution, individually or jointly, to at least one claim of the application.

While the conceived invention must include every feature of the subject matter claimed in the patent, each of the joint inventors need not make, for the conception of a joint invention, the same type or amount of contribution to the invention. Rather, each needs to perform only a part of the task which ultimately produces the overall invention. On the other hand, one does not qualify as a joint inventor by merely assisting the actual inventor after conception of the claimed invention has taken place - an inventor may engage the services, ideas and aid of others in the process of perfecting his or her invention without losing his exclusive inventor status and the resultant rights to the patent. A person is not a joint inventor if he/she did not conceive of a key feature of the invention and/or did not recognize the problem to be solved. Thus, one of ordinary skill in the art who simply reduced the inventor's idea to practice is not necessarily a joint inventor.

Joint inventors must, however, have labors that were conjoined with the efforts of the other named inventors - that is, when the inventors have some open line of communication during or in temporal proximity to their inventive efforts. Each joint inventor presumptively owns an undivided interest in the entire patent, regardless of his or her respective inventive contribution. Where inventors choose to cooperate in the inventive process, their joint inventions may become joint property without an express agreement to the contrary. In practice, when joint inventors are involved, it is recommended that each co-inventor should assign his or her rights to a single entity, whether that be one of the inventors or, more commonly, a corporate employer.

The issuance of a patent under U.S. law creates a presumption that the named inventors are the true and only inventors. Thus, it is important to maintain detailed documentation during the period of conception of an invention. A supposed inventor's mere testimony respecting the facts surrounding a claim of derivation or priority of invention cannot, standing alone, rise to the level of clear and convincing proof to establish joint inventorship contrary to the inventorship listed on an issued patent. (A party claiming to be a co-inventor of a patented invention must establish his co-inventorship status by clear and convincing evidence under the law.) Whether a supposed inventor's testimony has been sufficiently corroborated to establish joint-inventorship is evaluated under a Rule of Reason analysis: an evaluation of all pertinent evidence must be made so that a sound determination of the credibility of the alleged inventor's story may be reached. Corroborating evidence may take several forms:

(1) contemporaneous documents prepared by a putative inventor;
(2) circumstantial evidence about the inventive process; or
(3) oral testimony of someone other than the alleged inventor.

In closing, it is important that a company be careful in monitoring and documenting its inventive teams and in securing written assignments of the inventors’ rights to the company-employer. While in most states the law will generally view the employer as the owner of any invention conceived by an employee within his or her scope of employment, the preferred practice is to secure written assignments from each joint inventor and then to record those assignments with the U.S Patent and Trademark Office. It is even more important, if not absolutely critical, to secure written assignments from any co-inventor who is not an employee of the company, which is often the case when technology development occurs between or among collaborating companies. In this latter instance, there should be a written agreement in place between the companies prior to the work being performed spelling out how the resulting intellectual property rights, often called the “foreground rights,” will be assigned and owned between or among the companies.



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