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Cees Jansen

Cees Jansen

  • Engineering
  • European and Dutch Patent Attorney, European Patent Litigator
  • Of counsel

Cees Jansen graduated in Physics at the Delft University of Technology. He has held the position of head of the patent department at two large technology-driven companies before he joined V.O. in 1993. He focuses on that type of companies in his present practice.

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Cees has extensive expertise in high-tech systems such as radar, sonar, computer and telecommunication systems on the one hand and mechanical and physical systems on the other. In addition, he specializes in developing patent strategies to effectively protect systems, products, replacement products, parts of systems and semi products. He gained vast experience in opposition proceedings and litigation, in particular infringement and nullification suits, both nationally and abroad, including the USA.

Cees is member of the Commission for Patent Attorneys in Private Practice, FICPI and AIPPI. Since September 2019, Cees has been associated with V.O. as an of-counsel.

Working experience

  • Patent Attorney, V.O. (1990-September 2019)
  • Head patent department Hollandsche Signaal Apparaten (Thalis) (1986-1990) and Hunter Douglas (1990-1992)

Education

  • MSc in Physics, Delft University of Technology (1984)

Directories

  • “Cees Jansen is intimately familiar with the challenges and pressures facing innovative companies, having presided over large company patent departments. Not just a sympathetic ear, he has IP solutions and patent strategies to help his clients thrive” (IAM Patent 1000, 2021).
  • Recommended Individual (IAM Patent 1000, 2020, 2021, 2022).
  • Recommended in Who’s Who Legal 2020.
  • “The highest of high-tech companies make a beeline to Cees Jansen; he knows exactly what they are after, having served as head of patents in-house at two companies – unstintingly dedicated to quality, he always delivers” (IAM Patent 1000, 2019).
  • “Chair of the partnership Cees Jansen calls on his in-house experience when developing patent strategies for major companies. A technical all-rounder, he can be formidable when disputes heat up” (IAM Patent 1000, 2018).
  • “Technically strong and practical, Cees Jansen fronts the ‘s-Hertogenbosch office and devises pragmatic strategies for rights holders in the telecommunications and mechanics sectors” (IAM Patent 1000, 2017).
  • “Firm chairman Cees Jansen is well accustomed to leadership roles, having captained the patent departments of two technology companies before entering private practice. He is praised for his deep understanding of patent strategy” (IAM Patent 1000, 2016).
  • “On the high-technology front, chairman Cees Jansen is a good name to know. He drafts applications for many of Douwe Egberts’ top product lines” (IAM Patent 1000, 2015).
  • Recognized as IP Star (2015, 2014, 2017, 2018, 2019) by Managing Intellectual Property.
  • “Leading light Cees Jansen is enjoying his seventh year as chairman of the firm” (IAM Patent 1000, 2014).
  • “Cees Jansen is ‘one of the most experienced out there’. He works on both sides of the contentious and non-contentious divide, expecially in the areas of electrical engineering and information technology” (IAM Patent 1000, 2013).
  • “Chairman Cees Jansen has accumulated substantial experience of opposition, infringement and nullification proceedings in the Netherlands and abroad. His specialisms include sonar, telecommunications and computer systems” (IAM Patent 1000, 2012).

Professional & Community Activities

  • Member of the commissions for the Dutch examination of patent attorneys

Languages

  • Dutch
  • English
  • German

 

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News

Referral to the Enlarged Board of Appeal regarding the applicability of G 1/24 claim interpretation to added-matter analysis (T 873/24)

In T 873/24 (Board of Appeal 3.3.05, oral proceedings 3 February 2026), the Board announced that it will refer questions to the Enlarged Board of Appeal (EBA) on whether (and how) the Enlarged Board’s claim-interpretation guidance in G 1/24 extends to the assessment of added subject-matter under Article 123(2) EPC and Article 76(1) EPC.Continue reading

Interpreting claim terms “holistically” after G 1/24: description-based definition applied in T 0439/22 (Board 3.2.01)

In T 0439/22 (Technical Board of Appeal 3.2.01, 11 December 2025) the Board applied the Enlarged Board’s guidance in G 1/24 on claim interpretation. The decision is a practical illustration of how an explicit definition in the description can determine the meaning of a seemingly straightforward term used in the claims. As this case shows, […]Continue reading

Omission of drawings from the granted patent: limits of “deemed approval” and appeal as a remedy (T 0550/25) 

In T 0550/25 (Technical Board of Appeal, 10 February 2026), the Board addressed a recurring procedural mishap: drawing sheets are missing from the text annexed to a Rule 71(3) EPC communication and the patent is granted without them. The decision is practically significant because it confirms that, in such circumstances, the applicant’s grant fee payment […]Continue reading