Joint Ownership of Patents in South Korea

Under the Korean patent law, when there are joint inventors of a single invention, each inventor is entitled to be a joint owner in the right to obtain a patent of the invention. Without any agreement to assign his right, the joint owners must file an application for a patent together. Otherwise, the application shall be rejected or the granted patent shall be invalid. In the absence of an agreement to the contrary, each joint owner has an equal partial interest in the invention as a whole. When a company is an employer of an employee inventor and the employee is a co-inventor, the company shall be a joint owner of the invention through assignment.

The Korean patent law provides that joint patent owners may freely make, use and practice the patented invention without consent to the other joint owners. In this regard, each co-owner does not have the duty to account profits to the others.

However, each co-owner may not assign the partial right of the patent to a 3rd party without consent of the other co-owners. Namely a joint owner may sell his own interest in the paten only when the other joint owners consent such an assignment.

Furthermore, a joint owner may not license the patented technology to a third party based on his co-ownership of the patented invention unless he has obtained consent of the other joint owners about the license.

The Korean Patent Act has specific provisions for such restrictions of joint ownership. This principle of the Korean patent law is to protect each co-owner from an unreasonable change of co-ownership. If a joint owner may freely assign or license the jointly owned patent, other co-owners may be at the mercy of the co-owner. For example, in case a co-owner assigned his co-ownership to a large company and the other co-owner is a very small company and then a new co-owner large company may use and practice the patented technology as a whole independently without any duty of account profits to the other co-owners, the new joint may have the whole value of the patent and the small company does not have any profit.

However, joint owners may vary their rights by contract. The statutory default rule under the Korean patent law controls unless there is an agreement to the contrary.