A method patent is different from a product patent in that it protects a dynamic operation process. How to compare between the method used by the defendant and the patented process is a key point when the court tries an infringement case involving a process patent. In this case, by finding the technical feature difference of the products, the court held that the two processes are neither identical nor equivalent and thus the defendant does not infringe upon the plaintiff’s patent. This shows a new way for judging infringement upon a process patent.

The Interpretation of the Supreme People’s Court on Several Issues concerning the Application of Law in the Trial of Patent Infringement Dispute Cases stipulates, in Rule 6, “where the applicant or patent right owner abandons a technical solution through amendments to the claims and/or specification or observations during the prosecution of the application or the invalidation proceedings of the patent, the court shall not support the right owner’s claim of reclaiming the abandoned technical solution back into the protection scope in the infringement litigation case.” Therefore, application of the DOE is premised with a condition that the right owner has abandoned the technical solution through amendments or observations during the patent prosecution or invalidation proceedings.

An equivalent feature is a feature that, as compared to the feature described in a claim, performs substantially the same function by substantially the same means, produces substantially the same effect, and can be associated by an ordinary person skilled in the art without any inventive work. While determining whether a prosecuted product falls within equivalent infringement, the means, function, effect, and inventive work should be determined in the above order. Only when all four elements of a feature meet the above conditions, the feature can be determined as an equivalent feature.

When determining whether an infringement is established by employing the equivalent doctrine, it is necessary to compare technical features of an involved patent with those of an alleged infringing product, so division of technical features will influence determination of an equivalent feature. In this case, the Supreme People’s Court suggests that for division of technical features of a claim, a technical unit that is able to implement a relatively independent technical function generally should be considered as one technical feature, and it should not designate multiple technical units that implement different technical functions as one technical feature.

The case relates to an infringement dispute between Patentee, Wanqing BAI, and Chengdu Nanxun Marketing Service Center (hereinafter referred to as “Nanxun Center”), Shanghai Tianxiang Industry Co.,Ltd. (hereinafter referred to as “Tianxiang Industry”).

The patentee, Zhaoqing New Leader Battery Industry Co.,Ltd. et.al.(“New Leader Battery” hereinafter), has a utility model patent No. ZL01234722.1 titled “Mercury-free Alkaline Button Cell Battery.” The involved patent underwent three rounds of invalidation after the date of authorization proclamation. Finally, the Patent Reexamination Board (the “PRB” hereinafter) made the No. 13560 decision on the request for invalidation (hereinafter referred to as the invalidation decision) on June 9, 2008 declaring that all claims of the involved patent are invalidated. In the subsequent administrative litigation, both the court of first instance and second instance judged that the invalidation decision should be reversed.

Xi’an Qinbang Telecommunication Material Co.,Ltd. (hereinafter referred to as “Qinbang”) is the patentee of Chinese Invention Patent No. ZL01106788.8 titled “Method for Manufacturing Smooth Metal-shield Composite Belt.” Qinbang brought a patent infringement lawsuit to the Xi’an Intermediate People’s Court against three defendants including Wuxi Longsheng Cable Material Factory (hereinafter referred to as “Longsheng Factory”) and other two entities, claiming monetary damages and injunctions.

Claim interpretation is the key to determine the scope of protection of claims. The meaning of the claims can be determined based on internal and external evidence using a variety of interpretation methods, wherein the methods of interpretation can verify each other, eliminating contradictory, uncertain or ambiguous conclusions in order to obtain reasonable and accurate protection scope of the claims.

The judge held in this case that, if, by looking into the nature and degree of the typing mistakes, the person skilled in the art can naturally identify the typing mistakes and appreciate the corrected meaning of the typing mistakes, the typing mistakes shall be interpreted in a corrected manner. Consequently, negative effect of the typing mistakes on validity of valuable patents can be reduced, especially in the current circumstance where there exists no post-grant correction procedure for correcting typos and other clerk errors.

The judge proposed an important principle for claim construction in this case, holding that the claim construction should comply with the purpose of invention described in the detailed description of the patent application.