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Defeng Song



Defeng Song is a Partner in the intellectual property group of Fieldfisher. He is admitted as a lawyer in the People’s Republic of China and the State of New York, and holds the qualifications for the PRC patent bar and U.S. patent bar.

Defeng has a bachelor’s degree of engineering from Shandong University and three law degrees from China University of Political Science and Law, Hamburg University and New York University. With complex knowledge structure,  he has an excellent sense of both technology and law, as well as outstanding language skills. His working languages are Chinese and English.

Defeng’s practice covers the full-spectrum of intellectual property matters, with a major focus on patent, both contentious and non-contentious matters. He has successfully represented many household name clients from both China and beyond to act on patent infringement, patent invalidation, patent analysis, patent prosecution, and patent transaction and so on. He also is experienced in handling cross-border patent disputes and coordinating parallel patent litigation in multiple jurisdictions.

Prior to joining Fieldfisher, Defeng worked with both Chinese and international law firms for many years, including in his most recent position as head of IP at a multinational company.

Recent Articles by Defeng Song

A Case Study on the ‘Crime-Fraud’ Exception to Attorney-Client Privilege

The protection of privilege in communications between clients and lawyers is a very important one under U.S. law. The basic rule is that when a client seeks legal advice from a lawyer, the communication between the client and the lawyer is confidential and cannot be discovered during litigation. An important purpose of this rule is to encourage clients to communicate fully and freely with lawyers in the process of seeking legal help. The lawyers here include both external lawyers and in-house lawyers.

Examining Upcoming Changes to the Implementing Regulations of the Chinese Patent Law

Recently, amendments to the Implementing Regulations of the Chinese Patent Law were issued and will take effect from January 20, 2024. The Regulations align with the revisions made to the Patent Law in 2020 and provide further guidance. The main changes to the new Regulations, as compared with the 2010 version of the Regulations,  can be summarized as follows.