1. First of all, we should confirm the subject of the patent right according to the patent certificate, patent register and license agreement to see whether the plaintiff is a qualified patentee.
2. Secondly, it is necessary to confirm the validity of the patent right, including whether the patent right is still within the validity period of the patent right and whether it is protected by law. Is the stability of the special train evaluated by the patent evaluation report? Is there any possibility of ineffectiveness?
3. Then, judge whether the product accused of infringement is the same as or similar to the patented product? That is, whether the infringing product belongs to the scope of patent protection.
4. Finally, if the patent right is stable, and the product belongs to the scope of protection, and the defendant has no subjective intentional infringement, he should provide evidence such as legal source and prior use to prove that he has no subjective intention.
Legal basis: Article 120 of the Civil Law of People's Republic of China (PRC) infringes, and the infringed has the right to request the infringer to bear the tort liability. Article 183 Where an infringer damages himself by defending the civil rights and interests of others, he shall bear civil liability and the beneficiary may give him appropriate compensation. If no infringer or infringer escapes or is unable to bear civil liability, and the victim requests compensation, the beneficiary shall give appropriate compensation. Article 167 Where an infringement endangers the personal and property safety of others, the infringed party has the right to demand the infringer to bear the tort liability of stopping the infringement, removing the obstruction and eliminating the danger. Article 168 Where two or more persons jointly infringe and cause damage to others, they shall be jointly and severally liable.