The limitation of action for patent infringement is two years, counting from the date when the patentee or interested party knows or should know about the infringement. Where the patentee already knows or should know before the date of patent grant, it shall be counted from the date of patent grant.
Legal objectivity:
Limitation of action for patent infringement is the time limit to ensure whether the parties' claims can be supported by the people's court. If the limitation of action is exceeded, the obligee's claim will not be supported and the infringer's infringement will not be punished. According to the Patent Law of People's Republic of China (PRC), the limitation of action for patent infringement is two years, counting from the date when the patentee or interested party knows or should know about the infringement. After the publication of the application for a patent for invention, before the patent right is granted, the limitation period for the patentee to request payment of the royalties is two years, counting from the date when the obligee knows or should know that others are using his invention-creation, but if the patentee knew or should have known before the patent right was granted, counting from the date when the patent right was granted. People's Republic of China (PRC) and the Supreme People's Court's "Several Provisions on the Applicable Law in the Trial of Patent Dispute Cases" stipulate in the judicial interpretation; "The limitation of action for patent infringement is two years, counting from the date when the patentee or interested party knows or should know about the infringement. If the obligee brings a lawsuit for more than two years, and the infringement continues at the time of the lawsuit, the people's court shall order the defendant to stop the infringement within the validity period of the patent right, and the amount of infringement damages shall be calculated within two years from the date when the obligee brings a lawsuit to the people's court. " That is to say, if the obligee files a lawsuit after the limitation of two years, if the patent right is within the validity period, the people's court should still judge the defendant to stop the infringement, and the claim for compensation can be pushed forward for two years from the date of filing the lawsuit, that is, the part that exceeds two years will not be supported, and the judgment should still be made after the limitation of two years to ensure the rights and interests of the patentee and the punishment for the infringer. Whether the two-year statute of limitations is effective or not, the starting date becomes the key. In the patent law and judicial interpretation, it is clearly stipulated that the calculation should start from "knowing" or "should know". The legal knowledge means that the obligee or interested party knows that the infringement has occurred and his rights are infringed; However, knowing clearly means that the obligee or interested party objectively has the conditions and possibilities to know about the infringement, but does not know that their rights have been infringed due to subjective carelessness. If he knows it later, he should also calculate the limitation of action from the date when the conditions objectively exist. For example, two years ago, the infringer publicly publicized or participated in an exhibition of infringing products. Because the obligee was subjectively at fault, he didn't know that his rights had been infringed, but it was only two years later that he realized that the limitation of action should still be counted from two years ago.