Co-owners or joint-owners or co-applicants are used interchangeably to refer to one or more persons who have applied for a patent together in their name. Each joint-owner has the right to make, use, offer for sale, sell or import the patent for which he is a joint-owner. Section 51 of the Indian Patents Act deals with the rights of joint-owners.
It is envisaged in the Act that when a patent is filed in the name of two or more persons and granted in their names, then each of the joint-owners are entitled to an equal undivided share in the patent, unless they have an agreement to the contrary in writing. Thus, in order to ensure that there are no possible conflicts in future, it is advisable to draft and execute an agreement even prior to the filing before the Patent Office. It is pertinent to note that for a patent to be enforceable, the ownership of patent is an important element.
The joint owners cannot grant any license under the patent or assign its share in the patent without the consent of the other co-owners. The only respite is an appropriate direction given by the controller in such matters on the application of one party who may wish to license or assign the patent, and to which the co-owners are not agreeing. However, before issuing any such direction, the controller must give the other parties a show-cause notice and an opportunity to be heard.