Method patents pertain to the processes or technological procedures created for manufacturing products, which may involve chemical methods, mechanical processes, or methods described in procedural order. Because the implementation of these methods typically occurs within premises controlled by the defendant, it is difficult for the plaintiff to lawfully access these premises and gather evidence, making it challenging to enforce method patents. This issue is particularly pronounced for methods that do not result in new products, as the plaintiff cannot claim a shift in the burden of proof.
To address the difficulties in evidence collection, Article 3 of the "Supreme People's Court Provisions on Several Issues Concerning Evidence in Intellectual Property Civil Litigation" stipulates that under certain conditions, the court may apply a shift in the burden of proof. This article analyzes this issue through judicial cases to help method patent holders effectively exercise their rights and develop practical enforcement strategies.
According to the judicial interpretation, for products manufactured using a patented method that are not new, the plaintiff must provide evidence for the following three elements before a shift in the burden of proof can occur:
1、The products manufactured by the alleged infringer and those made using the patented method are the same.
Typically, the right holder can easily acquire the defendant’s products through notarized purchases. The patent description usually provides detailed information about the specific molecular structure, chemical composition, or properties of the manufactured products, making it relatively straightforward to determine if they are the same. For technical characteristics that are not directly discernible, testing by inspection agencies or certification by authentication institutions can be utilized. In practice, it is common to use test reports or authentication reports to prove that the products manufactured by the defendant are the same as those produced using the patented method.
2、It is highly probable that the products manufactured by the alleged infringer were made using the patented method.
"High probability" does not require the plaintiff's proof to reach a "high degree of likelihood" standard, but rather a standard similar to predominant evidence. However, proving this is not easy. The right holder needs to provide sufficient evidence to convince the judge and thus achieve a shift in the burden of proof. From practical experience and case studies, evidence can be gathered by demonstrating the link between unique steps in the patented method and the manufactured products. For example, residues detected in the products can reasonably suggest the materials added during the process; traces on the product's surface can infer the processing techniques used. Another approach is through proving the source of the technology, such as if the defendant had access to the relevant technology or if their technology originated from the plaintiff’s.
3、The right holder has made reasonable efforts to prove that the alleged infringer used the patented method.
The judicial interpretation does not specify what constitutes "reasonable efforts," but the legislative intent suggests it should consider the specifics of the case, the facts known, the capabilities of the parties to provide evidence, and the difficulty of gathering evidence. Firstly, if the right holder has not attempted or made an effort to use common methods like notarization or evidence preservation, it is clear they have not made reasonable efforts. For instance, the Beijing Intellectual Property Court in case (2018) Jing 73 Min Chu No. 1601 held that the plaintiff had not made reasonable efforts as they failed to notarize the process of purchasing the allegedly infringing products, despite being fully capable of doing so. Similarly, the Shandong High People's Court in case (2019) Lu Min Zhong No. 20 found that the plaintiff did not make reasonable efforts as they did not take appropriate measures to preserve evidence before or during the litigation. Secondly, "reasonable efforts" also mean exhausting all available means of evidence collection. As long as there are still legal ways to obtain evidence, a judge might consider that the plaintiff has not made reasonable efforts. In case (2021) Supreme Court Zhi Min Zhong No. 1305, the plaintiff not only submitted notarized documents and test reports but also obtained evidence from administrative agencies like the Environmental Protection Bureau and Customs, leading the Supreme People's Court to recognize that the plaintiff had made reasonable efforts considering the difficulty and cost of obtaining evidence, the amount of evidence provided, and its relevance and probative value in the litigation.
From the above cases and analysis, it is evident that while the judicial interpretation reduces the burden of proof for the plaintiff to some extent, as the primary party responsible for providing evidence, the plaintiff should exhaust all means of evidence collection. They should fully substantiate the three conditions specified in the judicial interpretation, at least preliminarily proving the plausibility of the claimed facts, thereby persuading the court to apply a shift in the burden of proof.
