Japanese Patent FAQs
Q.Where a patent right is jointly owned, is the exploitation by each of the joint owners allowable without consent of all joint owners?
Except as prohibited by contract, each joint owner may manufacture, sell, or offer for sale a patented product without the consent of the other joint owners. It thus appears that exploitation by each of the joint owners is allowable except when otherwise forbidden by contract.
Consent of all other joint owners would be required for any of the following:
i) transferring a partial share of the jointly-owned patent,
ii) establishing a pledge of the share, or
iii) granting an exclusive or non-exclusive license.