Masahito (Masa) Yokoyama is a partner in the firm’s Electrical Patent Prosecution group. Mr. Yokoyama’s legal experience covers all aspects of client counseling, patent portfolio development and management, patent prosecution, opinions of counsel, due diligence, freedom to operate counseling, and pre-litigation counseling. Mr. Yokoyama prepares and prosecutes U.S. patent applications covering a wide range of areas including consumer electronics, computer hardware/software, communication/broadcasting technologies, display technologies, data storage technologies, imaging technologies, medical devices and semiconductor devices.

Before joining the firm, Mr. Yokoyama was a patent attorney in the intellectual property division of Hitachi, Ltd. and Sony Corporation for 10 years, specializing in worldwide patent prosecution, patent portfolio development and management, patent standards, patent litigation, pre-litigation analysis, patent enforcement and cross licensing.

An attorney and native of Japan with 10 years working experience in international companies and an engineering background, Mr. Yokoyama is particularly skilled in providing clients with practical advice to support their business through technical and legal analysis.


  • University of Pennsylvania Law School (LL.M.)
  • Chuo University (LL.B.)
  • University of Tokyo (M.E.)
  • University of Tokyo (B.E.)


  • District of Columbia
  • Japan Patent Office
  • Registered to practice before the U.S. Patent and Trademark Office (limited recognition under 37 CFR §11.9(b))
  • Tokyo and Osaka District Courts and IP High Courts in specified infringement litigation


Professional Affiliations

  • American Bar Association
  • American Intellectual Property Law Association (AIPLA)
  • District of Columbia Bar


  • Japanese