Exceptions determining functional features in disputes

By Geng Yunfeng, Wan Rui Law Firm

Article 8(1) of Interpretation (II) of the Supreme People’s Court on Several Issues Concerning the Application of Law in the Trial of Disputes over Infringement of Patent Rights provides a general definition of the functional features, which refers to technical features that limit the structure, composition, steps, conditions, or their interrelationships based on the features’ functions or effects in invention or creation, except for cases where a general technician in the field can directly and clearly determine the specific implementation of the above-mentioned functions or effects by reading the claims.

In judicial practice, determining whether a disputed technical feature is a functional feature or a non-functional feature is often the focus of dispute between the plaintiff and the defendant. The plaintiff mostly tends to interpret the disputed technical feature as a non-functional feature to obtain a broader scope of protection, while the defendant often focuses on interpreting it as a functional feature to achieve the goal of non-infringement defence. This article discussed the two exceptional situations of functional features based on current judicial practice.

The feature category of “the manner of implementation of which is known to a general technician by reading the claims” is an exception. Article 8(1) of Interpretation (II) provides for an exception where a general technician in the field could directly and clearly determine the specific manner of implementing the mentioned function or effect by merely reading the claims.

In SMC Corporation v Yueqing Bosun Pneumatic Equipment, a dispute over infringement of patent rights for inventions before the Supreme People’s Court, SMC submitted evidence such as the texts China Power Encyclopedia, Hydraulic Valves and Hydraulic Technology. The court determined that the evidence provided by SMC was sufficient to prove that the specific implementation methods to achieve the disputed technical feature were common knowledge for a general technician in this field.

Therefore, the disputed technical feature falls within the situation where a general technician in this field can determine the specific implementation methods directly and clearly through the reading of the claims, and thus does not constitute a functional feature.

It is important to note that, in the case of an exception to functional technical features, the burden of proof lies with the plaintiff, and it is preferable to provide evidence that falls under the category of common knowledge in this field such as textbooks, reference books, technical dictionaries, etc., to enhance the persuasive power of the evidence.

Geng Yunfeng, Wan Rui Law Firm
Geng Yunfeng
Wan Rui Law Firm

Exception for features of the “orientation or structure + functional description” category. The Supreme People’s Court, in the case of Xiamen Lucas Auto Parts Company v Valeo Systemes d’Essuyage, highlighted that if a technical feature already specifies or implies the specific structure, component, step, condition, or their interrelationships of the invention’s technical solution, even if it also defines the function or effect achieved, is generally not considered a functional feature and should not be used for infringement comparison.

In this case, the Supreme People’s Court determined that the technical feature described in claim one of the patent in question not only defined a specific orientation and structure but also specified the function associated with them.

The specific content of the orientation and structure required a comprehensive understanding of the elements mentioned above to be determined. Despite containing a functional description, this feature fundamentally remains an orientation or structure feature and does not fall under the functional feature definition stated in article 8 of Interpretation (II).

It is important to note that this exception for features of the “orientation or structure + functional description” is a principled exception, and not all features of this type are automatically non-functional. In theory, they could still be classified as functional features.

In the patent infringement dispute case of Sensah v Shimano, the plaintiff argued that the disputed technical feature has clear descriptions of the structural and movement relationship between the first operating component and the mounting component, indicating that it is not a functional feature.

However, after reviewing the case, the court determined that although the structural relationship between the first operating component and the mounting component was clearly described, the specific function directly related to the technical problem solved by the patent, which is the inventive point of the patent, could not be directly obtained from the above-mentioned descriptions, specifications, or the description of the existing technique.

In other words, the above-mentioned technical feature only clearly indicates the ability to achieve a certain function but does not directly disclose the specific implementation methods of that feature. Therefore, the above-mentioned technical feature falls into the category of functional technical features, requiring additional disclosure of the essential implementation methods in the specification to further define its content.

Based on the analysis of these two cases, the key determinant of whether “orientation or structure + functional description” type features are considered functional features lies in whether a general technician in the field can clearly and unambiguously determine the specific implementation methods to achieve the function or effect solely based on the description in the claims. If this is possible, it can generally be excluded from the category of functional features; otherwise, it cannot.


When representing clients in patent infringement cases where the technical features of the patent in question may be considered functional features, lawyers should carefully study these features during the case preparation stage, communicate extensively with the inventors, and assess the probability of these features being classified as functional features based on relevant laws and judicial practices. It is crucial to gather relevant supporting evidence in order to effectively address various situations that may arise during the trial.

Geng Yunfeng is an associate at Wan Rui Law Firm. Wan Rui Law Firm is a member of Sanyou IP Group

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