Written by:Xu Jing Zhang Chao(Intellectual Property)




In a patent infringement case involving medium-voltage drives, the KWM team representing the client Siemens successfully convinced the court to establish the infringement by relying on written evidence only, without any physical sample of the accused product for technical comparison, and the claim for damages was fully supported by the court. This case provides a new approach on evidence production for patent infringement cases, which may be a valuable reference in particular for a patent involving an industrial equipment, of which the physical sample may be too large to be submitted to the court.

Siemens AG (Germany) (i.e. the plaintiff in this case), the client of King & Wood Mallesons, is a technology company focused on industry, infrastructure, transport, and healthcare. In its own AC drive products, Siemens makes use of the innovative technology called “neutral point shifting”, which was protected by Siemens patents in many countries, including the patent asserted by the plaintiff in this case (“patent at issue”). In late 2017, Siemens found that Suzhou Inovance Technology Co., Ltd. (“the defendant”) promoted in articles of its official website and its product brochure that the accused medium-voltage drives adopted the neutral point shift technology (the defendant called it as “asymmetric bypass technology”). The articles also used a figure which is totally the same as Figure 5a in the patent at issue to describe its “asymmetric bypass technology”, which was therefore suspected of constituting patent infringement. After the attempt of negotiation failed, Siemens filed a lawsuit to Suzhou Intermediate People’s Court in March 2019, claiming damages of CNY 6 million.

The medium-voltage drives involved in this case is a typical industrial product, which is often used in high-end applications in industries such as iron and steel, electrical, coal mining and petrochemical. Such variable speed drives have a high price (from some hundred thousand to one million CNY per product), and are sold to specific customers. Thus, unlike low-voltage drives, they are not sold in large quantities, making it extremely difficult for the plaintiff to acquire a physical product and present it to the court as evidence. The plaintiff could only collect written evidence from public channels, including the product brochure of the accused product, the articles published by the defendant on the official website and journals, to prove that the accused product is of high likelihood to fall into the protection scope of the patent at issue, through the defendant’s own descriptions on the accused product. Accordingly, in the absence of physical product, whether the infringement can be determined solely on the basis of written evidence became one of the main issues in this case.

In this case, the defendant argued that the articles and product brochure submitted by the plaintiff were only for the defendant’s commercial promotions, which could not reflect the true or complete technical solution actually adopted by the accused product, and therefore they could not be used as the basis for infringement comparison. The first-instance court held that the current law does not explicitly requires that the infringement comparison must be made on the basis of a physical sample of the accused product. Even without a physical product, as long as the existing evidence materials can objectively and truly reflect the method actually adopted by the accused product, they can be used for the determination of infringement. The defendant’s descriptions on the accused product and its technical solution, which were published on its official website and public media, shall be presumed to truly reflect the specific technical solution adopted in relevant products. Although the defendant is the supplier of the accused product, it only made negative defenses but did not submit any evidence. Hence, the first-instance court declined to consider the defenses of the defendant. The Intellectual Property Court of the Supreme People’s Court of China (“the IPC of SPC”) affirmed this in the second instance. The IPC of SPC pointed out that inspection of physical product is only one of the effective methods for identifying the technical facts of the accused solution and for conducting infringement comparison, which implies that the comparison based on physical product is not the sole method for infringement determination.

According to the written evidence submitted by the plaintiff, when describing the technical solution of the accused product, the defendant used a figure which is exactly the same as the embodiment shown in Figure 5a of the patent at issue. Therefore, the first-instance court concluded that the accused product fell within the protection scope of the patent at issue, and fully supported the plaintiff’s claim for damages of CNY 6 million. The IPC of SPC issued a final judgment in the end of 2021 (Case number: (2020) ZUI GAO FA ZHI MIN ZHONG No. 1593), upholding the first-instance judgment.

In a typical patent infringement case, the right holder usually needs to submit a physical sample of the accused product as evidence to the court, or apply to the court for evidence preservation to conduct on-site inspection to investigate the physical sample, so as to identify the technical features of the accused product corresponding to those defined in the patent claims. However, for patentees of patents involving large industrial products, it may become extremely difficult or even impractical to do notarized purchase of a physical product and to further submit the purchased product to the court, to fulfill the evidence production requirement. The rule and principle reflected in the above precedent of the SPC is undoubtedly favorable for the right holders in mitigating the afore-mentioned difficulty in evidence production. It provides a new approach on evidence production for the patentee. That is, when it is not available to purchase a physical sample of the accused product, the patentee may first try its best to collect written evidence to prove that the accused product has a high likelihood of infringement, and then request the court to make a presumption against the accused infringer based on the rules of shift of the proof burden. For the accused infringer, it should adopt a more positive strategy on evidence production according to the specific circumstance of the case, instead of persisting in the outdated prejudice that the plaintiff shall assume all burden of proof.