About Us - DSL Patents

About Us – DSL Patents

DSL Patents

DSL Patents is a registered patent agency based in the Greater Toronto Area (Markham-Stouffville region).  However, we operate a location-independent practice.  As a result, we support Canadian firms and inventors from coast to coast across Canada (and even beyond).  Some of our clients are based in Toronto, Ottawa, Montreal, Peterborough, Vancouver, Edmonton, Calgary, Winnipeg and Charlottetown, as well as the US.

Dennis S. Leung

Our CEO and principal is Dennis S. Leung, a registered Patent Agent (Canada, US: 2000).  He has prepared anDennis Leung DSL Patents Inc.d prosecuted patent applications in Canada, the US and around the world including in:


Dennis has prepared electrical and software patent applications for many of the world’s leading tech companies and multinational communications giants.  He was a patent and IP litigator and in-house counsel to a leading reverse-engineering company supporting world-wide patent licensing programs.  This helps us to prepare high quality patent applications for our clients that can withstand litigation and/or validity challenges.

Additional Expertise

The issue of patentable subject matter impacts patents for software, and increasingly in other fields, including the financial sector.  We have identified numerous techniques that have been successful to overcome difficult Office Action rejections related to this issue.

Our claim construction expertise continues beyond Dennis’ work as counsel on the leading SCC case on the topic.

Dennis was sought after to author the Canadian chapter on Patent Claim Interpretation – Global Edition (Thomson-West, 2008-2010).  He presented a webinar on Global Patent Claim Interpretation (Thomson-Reuters) in September 2008.

Additionally, Dennis taught Patent Law at Queen’s University’s Faculty of Law for several years.  He trained many of today’s current registered Canadian patent agents on each of the topics of the Canadian patent agent exams, both in IPIC’s Patent Agent Tutorials (Infringement and Validity) and as  lead instructor in Module I (Drafting and Prosecution) of its intensive Patent Agent Training Course.

We are currently working on a project to provide instruction to lay inventors on how to draft patent applications.