In April 2023, Company A and Company B signed a "Patent Transfer Contract", which stipulates that Company B will transfer, without limitation, all entities related to the patent right, whether before or after the transfer, to Company A. In May 2023, Company A submitted a request to the China National Intellectual Property Administration for the change of bibliographic items, requesting that the patentee be Company A. In July 2023, the China National Intellectual Property Administration issued the Notice of Conformity and approved the change. Now, Company A has been changed to the legal obligee of the patent. After receiving the patent, Company A discovered that Company A has been producing products that infringe on the patent since 2020. Therefore, Company A filed a lawsuit with the court requesting that Company A stop the infringement, compensate for economic losses, and maintain reasonable rights and expenses.

In the lawsuit, Company A claimed that Company A was not the patentee before the patent was transferred and had no right to claim economic losses from Company A before the patent was transferred. Company A proposes that the patent right shall be transferred upon transfer, which includes not only the patent right itself, but also the right to sue for and receive compensation for infringement before and after the patent transfer.

After trial, the court found that the transfer of the patent right in question was in accordance with the relevant provisions of China's Patent Law. Regarding the ownership of litigation rights before and after the transfer of the patent right, the original patentee, Company B, has clearly defined the ownership of litigation rights to Company A through an agreement, which is not prohibited by current laws. Therefore, even if the patentee at the time of the alleged infringement is not Company A, However, as the current patentee, Company A has also obtained all the litigation rights of the involved patent according to the agreement, and has the right to file a lawsuit against the patent infringement behavior that occurred before it was transferred and obtained the involved patent right. Therefore, Company A has the qualification of litigation subject.

Based on the perspective of the judgment in this case, the author believes that the court may consider the following two factors: on the one hand, under the framework of China's patent law, patent rights can be transferred, and the transferee changes to the patentee after legal transfer procedures. The agreement between the transferor and the transferee in the patent transfer contract that the transferee shall obtain the right to sue for patent infringement prior to the transfer belongs to the scope of mutual autonomy, and this agreement does not violate the prohibitive provisions of the law. On the other hand, it is more economical and convenient for the assignee to file relevant infringement lawsuits to avoid litigation burden.

In summary, in order for the patent assignee to obtain the right of action for patent infringement that occurred before the patent assignment, it is necessary for the assignor and assignee to agree in the patent assignment contract, or for the assignor to authorize or make a statement that the right of action belongs to the assignee.