특허무효와 특허실시료 반환과의 관계

Usually, a property or good is transferred based on a valid legal relationship. In such case, the law of unjust enrichment does not work. In a case when a legal relation is invalid or inexistent, the law of unjust enrichment works. A patentee may grant an exclusive license or non-exclusive license of the patent right to others. A exclusive or nonexclusive licensee is entitled to work the patented invention commercially or industrially to the extent prescribed in Patent Act or allowed by the license contract. This study is dealing with invalid of patent and repayment of royalty. Where a trial decision invalidating a patent has become final, the patent right is deemed never to have existed. In accordance with, the patentee is no longer capable of enjoying the patent right. Royalty that have been paid may be repaid if licensee requested.