Guidelines for Using Expert Witnesses in Chinese Patent Litigation

In China, the number of patent litigation cases has been increasing, and the cases have become more complex. In both patent civil infringement litigation and patent administrative procedures, the determination of technical facts is often the key to case adjudication. Expert witnesses, as individuals with specialized knowledge, play a crucial role in assisting the court in understanding complex technical issues. The purpose of this document is to analyze the legal basis for the use of expert witnesses in Chinese patent litigations, their practical application in judicial practice, and the considerations that need to be taken into account. This will provide guidance and reference for relevant parties and lawyers.

• Legal Status and Role of Expert Witnesses

In Chinese patent litigation, an expert witness refers to an individual with specialized knowledge who provides opinions or explanations on technical issues involved in the case. The role of expert witnesses is primarily to help the court understand complex technical issues and provide professional opinions to judges, thereby assisting the court in making fair judgements.

• Case Analysis of Courts Adopting Expert Witness Opinions

In the case of Valeo Cleaning Systems Co. v. Xiamen Lucas Automotive Parts Co., Ltd. (Supreme People’s Court Civil Judgment (2019) Zui Gao Fa Zhi Min Zhong No. 2), the professional responses of the expert assistant were explicitly recognized by the Supreme People’s Court.

In the case of Litens AUTOMOTIVE (Suzhou) Co., Ltd. v. Gates Unitta Power Transmission (Shanghai) Co., Ltd., Chery AUTOMOBILE Co., Ltd., et al. (Jiangsu High Court Civil Judgment (2015) Su Zhi Min Zhong No. 00172), all parties provided expert assistants to the court, including professors from the Mechanical Engineering Department of Virginia Tech, Tongji University, Tsinghua University, and Nanjing University of Aeronautics and Astronautics, etc. During the trial, the technical experts from all parties engaged in in-depth discussions on the interpretation of the claims, the accused infringing technical solutions, and the technical issues involved in the prior art defence, fully expressing their opinions. All parties and experts agreed to leave the final determination and ruling on the technical issues to the court.

• Case Analysis of Courts Rejecting Expert Witness Opinions

In Warner-Lambert Company LLC v. Beijing Jialin Pharmaceutical Co., Ltd. (2014 Xing Ti No. 8), Warner-Lambert submitted Evidence 7 (MIT Professor Allan S. Myerson’s testimony) and Evidence 8 (Karen S. Gushurst’s testimony and experimental reports) to prove that a person skilled in the art could implement the invention based on the patent specification, complying with Article 26(3) of the Patent Law. During cross-examination, the Patent Re-examination Board and Jialin argued that Evidence 7’s witness did not appear in court, and Evidence 8 relied on unilaterally commissioned experiments, making them inadmissible as sole bases for the ruling. The Supreme Court held that Warner-Lambert’s notarized documents failed to certify the experts’ qualifications or experimental processes, which were critical to the evidence’s admissibility. Additionally, Evidence 7 reflected expert opinion, not the perspective of a person skilled in the art, and Evidence 8 included experimental details absent from the patent specification. Consequently, the Court rejected Evidences 7 and 8.

• Considerations for Using Expert Witnesses in Chinese Patent Civil Infringement and Administrative Validity Procedures

Based on the above cases and the author’s own experience, the following considerations should be taken into account when using expert witnesses in patent civil infringement and administrative validity procedures:

1. Qualifications of the Expert

1.1 Professional Knowledge and Experience

Expert witnesses should have deep professional knowledge and extensive practical experience in the technical field related to the patent, such as mechanical engineering, electronic information, or biomedical engineering. For example, in cases involving mechanical patents, the expert should be an engineer or scholar with years of practical and research experience in mechanical design and manufacturing processes.

1.2. Industry Recognition

Ideal expert witnesses usually have a certain level of recognition and reputation in the industry, which can be demonstrated through participation in industry standard setting, publication of industry-related papers, or involvement in research projects. For example, in integrated circuit patent cases, expert witnesses who have participated in the formulation of national integrated circuit technology standards often have more authoritative opinions.

1.3. Neutrality

Expert witnesses should maintain a neutral stance and should not have any interest in the case. Although expert witnesses are commissioned by the parties, they have an obligation to remain objective and impartial, providing opinions based on professional knowledge and scientific facts.

2. Standards for Reviewing Expert Opinions

2.1. Relevance to Case Facts and Formal Requirements of Evidence

Expert opinions must be relevant to the technical facts of the patent involved in the case. Experts should not provide technical analysis unrelated to the disputed issues. For example, in patent infringement litigation, if the disputed issue is whether the technical features of the accused infringing product are equivalent to a certain technical feature in the patent claims, the expert should provide relevant opinions on this equivalence judgment rather than evaluating the innovativeness of the patent technology.

Additionally, expert opinions should meet the general formal requirements of civil evidence, such as notarization and legalization when necessary.

2.2. Evidentiary Support

Expert opinions are best supported by certain evidentiary materials. For example, in a patent litigation case in the OLED field where we represented a party, the expert witness provided a witness statement along with a computer simulation report and comparative test results. After cross-examination organized by the court, the expert witness’s testimony was accepted by the court.

3. Interaction and Training Between Litigation Lawyers and Experts

In cases personally handled by the author, it has been deeply realized that litigation lawyers not only need to have a keen eye to select suitable expert assistants but also need to fully communicate with the experts throughout the litigation preparation process. This helps the experts overcome legal barriers and better translate their technical expertise into easily understandable language. For example, technical experts can use PPTs, animations, or edited videos to explain technical issues, while avoiding simply reading pre-prepared written materials. At the same time, litigation lawyers should provide appropriate training to experts to help them adapt to the courtroom environment in advance, facilitating better expression of their professional opinions.

• Conclusion

Expert witnesses play an increasingly important role in Chinese patent litigation, providing professional support for courts to understand complex technical issues. By analyzing cases where courts have adopted or rejected expert witness opinions, we can see that the adoption of expert opinions depends on their professionalism, objectivity, and relevance to the case facts. With the continuous improvement of relevant legal systems and the accumulation of judicial practice, the application of the expert witness system in patent litigation will become more standardized and effective. In the future, as technological innovation advances and patent disputes become more complex, the role of expert witnesses will become even more prominent. Therefore, further improving the expert witness system, enhancing the professional level and testimony quality of expert witnesses through the cooperation of litigation lawyers and experts, is of great significance for promoting the fair and efficient adjudication of patent litigation.