In this lawsuit, the Plaintiff SEB S.A. fully studied how to seek protection when the claims were defined by function or effect. It chose the claims carefully to lower the risk in the litigation.

Legal and Regulatory Background

The “Supreme Court’s Interpretation of Certain Issues on Application of Laws in the Trial of Patent Infringement Disputes” (2010)

Article 4: If a claim states the technical features in terms of functions or effects, the people’s courts shall determine the content of the technical features by taking into account the specific method to achieve such functions or effects as described in the specification and drawings or any equivalent method.

Case Summary

In 1995, SEB applied for an invention patent No. ZL95109146.8 for “a device which controls the opening and closing of a pressure cooking vessel with a clamp”. The patent was granted in 1998.

At the Canton Fair of April 2011, SEB found that a Guangdong-based company named KERN was offering for sale a pressure cooker which was suspected of infringing the above patent. SEB immediately filed a complaint with the IPR Complaints Reception Office of the Canton Fair who, after examination, affirmed the infringement and disposed of the infringing product accordingly.

In July 2011, SEB conducted a notarized purchase of samples from KERN, and filed a civil  lawsuit against KERN for infringement of the said patent before the Guangzhou Intermediate Court, citing claims 1, 3 and 12 of its patent.

In November 2012, the Court held that the Defendant's pressure cooker fell under the protection scope of the claims 1, 3 and 12 of the Plaintiff’s patent. The Court ordered KERN to stop the infringement, to destroy the tooling specifically for manufacturing the infringing products, and to pay SEB an amount of RMB 300,000 as damages.

KERN appealed to the Guangdong High Court. In December 2014, the Guangdong High Court rendered the final decision stating that the pressure cooker infringed claims 1 and 12 of the patent, but not 3. The Guangdong High Court found that the three claims had technical features which were described in terms of functions. The Court construed the three claims by studying the specification and drawings of the patent, and defined the protection scope of the claims by listing separately and side by side all the necessary technical features as shown in the specification and drawings.

WAN HUI DA represented SEB S.A. in this case.


The purpose of the Supreme Court in selecting this lawsuit as a typical case is to clarify how to define the protection scope of a claim when the technical feature is described in terms of functions or effects. Before filing the lawsuit, SEB S.A. fully considered the problem of how to seek protection when the claims are drafted in terms of functions or technical effects, and studied the practice of different courts. It then selected three claims that had the best chance of being supported by the court.