Photograph of Richard R. Diefendorf

Richard R. Diefendorf


Richard R. Diefendorf has over 30 years of experience as an attorney concentrating in intellectual property law. Before entering private practice, he was employed for five years as a U.S. Patent Examiner.

Mr. Diefendorf is involved in all aspects of domestic and foreign patent procurement, and has extensive patent application drafting experience. He routinely handles administrative appeals to the U.S. Patent and Trademark Office Patent Trial and Appeal Board, and is experienced in providing legal opinions on patentability, patent validity and patent infringement. Mr. Diefendorf frequently lectures on U.S. patent law and procedure to technology companies and other organizations, and has provided assistance to entities in addressing export control and due diligence issues.

Mr. Diefendorf's technical experience extends to a variety of fields, and he has successfully prosecuted applications relating to cores for alternating current power generators, electric motors for rotary pumps and throttle valves, actuators for automotive brake, lock, transmission, fuel injection, engine control, and ignition systems; electromagnetic motors, actuators, and components; optical disc imaging devices; printers and photocopiers; heat pumps; heating and air conditioning systems; fuel cells; radar systems; dental equipment; medical equipment, including pacemakers, stent arrangements, and magnetic resonance imaging equipment; aircraft components; ordnance detonation devices; optical sensors; filtering and purification systems; integrated circuit manufacturing equipment and processes; satellite communications systems; and missile guidance systems.

Mr. Diefendorf is actively involved in pro bono work, volunteering at the D.C. Superior Court Landlord Tenant Resource Center and conducting intake interviews for the legal network of a church-affiliated community service organization. Mr. Diefendorf has also obtained several U.S. patents for a non-profit entity serving developing African communities and helped address licensing issues associated with those patents on a pro bono basis.


  • University of Rochester, B.S. (1981) mechanical engineering
  • George Mason University School of Law, J.D. (1989)


Admitted to practice: District of Columbia, Virginia, Court of Appeals for the Federal Circuit, U.S. Patent and Trademark Office (USPTO)

American Bar Association

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"Changes To Product, Coupled With Opinions of Counsel, Compel Reconsideration of Willfulness Finding," Intellectual Property Bullet Analyses (August 29, 2008). Contacts: Mark Supko, Richard R. Diefendorf
Client Alert / Newsletter
"Determining Suitability of Invention for Customer Purpose is not Experimental Use," Intellectual Property Bullet Analyses (February 26, 2008). Contact: Richard R. Diefendorf
Client Alert / Newsletter
"Dependent Claims May Be Definite Although The Independent Claim Is Not," Intellectual Property Bullet Analyses (February 4, 2008). Contact: Richard R. Diefendorf
Client Alert / Newsletter
"Incorporation By Reference Statement Must Be Drafted With Care," Intellectual Property Bullet Analyses (November 14, 2007). Contact: Richard R. Diefendorf
Client Alert / Newsletter
"Arguments Unrelated To Patentablilty Preclude Infringement," Intellectual Property Bullet Analyses (September 17, 2007). Contact: Richard R. Diefendorf
Client Alert / Newsletter
"Analogous Art May Come From Any Area Describing Similar Mechanisms," Intellectual Property Bullet Analyses (August 7, 2007). Contact: Richard R. Diefendorf
Client Alert / Newsletter
"Patent Claim Term’s Definition Redefinition Permitted Despite Absence In Specification," Intellectual Property Bullet Analyses (July 9, 2007). Contact: Richard R. Diefendorf
Client Alert / Newsletter
"Business Method Patents: An Update," The Inquisitive Mind: The Intellectual Property Rights Newsletter, Volume 1, No. 2, Page 5 (June 2002). Author: Richard R. Diefendorf.

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