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Yeah-Sil Moon is a leading U.S. and Korean patent lawyer as recognized by Chambers, Super Lawyers, and The New York Times. Her 30-year practice is an extraordinarily rich experience of successfully handling patent prosecution, litigation, and strategic counseling matters for clients in the pharmaceutical, biotechnology, chemical, automobile, telecommunication, electronic, mechanical, and medical device sectors. Yeah-Sil has prosecuted and enforced patents worldwide for some of the most successful therapeutics. She has assisted BMS (formerly Celgene Corp.) in establishing its global patent portfolio, including prosecution, strategic counseling, litigation, inter partes review (IPR), opposition, invalidation, and transactions for products including billions dollar a year drugs REVLIMID®, POMALYST®, OTEZLA®, ONUREG®, VIDAZA®, THALOMID®, and ABRAXANE® for treating cancers and immune, inflammatory conditions.

Yeah-Sil has successfully defended patent infringement actions in various district courts and the International Trade Commission (ITC). Recently she achieved a tremendously important victory for SK Innovation against LG Chem in a patent infringement dispute before the ITC involving lithium-ion battery technology used in electric vehicles. She also obtained Federal Circuit's decision affirming a summary judgment of noninfringement for PI Advanced Materials (SKC Kolon PI) and won a jury verdict of noninfringement for SOLiD in the Northern District of California. Yeah-Sil also has in-depth experience in IPR. She has significant experience with patent prosecution, litigation, opposition, and invalidation proceedings in Asia, Europe, Australia, Mexico, and Brazil.

Yeah-Sil leads the Firm's Korea Practice and is a member of the Firm's Patent Prosecution Council. She regularly travels to Korea to visit clients and to lecture on hot topics of U.S. and international IP protection.


  • SOLiD defeats patent infringement claims in U.S., UK, and Germany over DAS equipment for 5G technologyJones Day successfully represented SOLiD, Inc. in multi-jurisdictional patent litigation proceedings brought by a competitor who alleged that client's leading Distributed Antenna System ("DAS") solutions infringe claims of six patents (two European and four U.S.).
  • Hanwha secures voluntary dismissal of patent litigation involving image processing technologyJones Day successfully represented defendant Hanwha Techwin America, Inc. ("Hanwha"), a manufacturer of security cameras, in a patent litigation matter in the District of New Jersey.
  • SHEnB defends against patent infringement claims at ITC involving skin treatment devicesJones Day is lead counsel defending Sung Hwan E&B Co., Ltd. ("SHEnB"), a Korean manufacturer of medical devices for the health & beauty industry, and two of its distributors against patent infringement claims brought by Serendia, LLC before the International Trade Commission.
  • CJ CheilJedang defends German patent infringement action by Japanese competitorJones Day represented CJ CheilJedang Corporation, a major Korean-based multinational company, in an international patent dispute with a Japanese competitor before the courts in Germany, including the Federal Supreme Court of Germany.
  • Hanwha Techwin obtains dismissal of patent infringement claims related to camera imaging modulesJones Day successfully defended Hanwha Techwin Co., Ltd. from patent infringement claims related to two patents on the design of imaging modules for optics and cameras.
  • SK Innovation defeats request to exclude lithium-ion battery technology in ITC dispute with LG ChemJones Day clients SK Innovation Co., Ltd. and SK Battery America, Inc., following an evidentiary hearing in December 2020, prevailed against LG Chem et al. in a patent infringement dispute before the International Trade Commission (ITC) involving lithium-ion battery technology used in electric vehicles.
  • SK Innovation resolves global patent dispute with LG Chem / LG Energy Solution over lithium-ion battery technologyJones Day advised SK Innovation Co., Ltd. and SK Battery America, Inc. in connection with the settlement of their global patent dispute with LG Chem Ltd. involving lithium-ion battery technology used in electric vehicles.
  • PI Advanced Materials obtains CAFC affirmance of summary judgment win in patent case regarding polyimide filmsJones Day successfully obtained a Federal Circuit affirmance of a summary judgment win of non-infringement on behalf of PI Advanced Materials Co., Ltd. ("PIAM", formerly SKC Kolon PI, Inc. ("SKPI")).
  • Celgene acquired by Bristol-Myers Squibb for approximately $74 billionJones Day advised Celgene Corporation (NASDAQ: CELG) in connection with the intellectual property and technology transactions aspects of its cash-and-stock merger with Bristol-Myers Squibb (NYSE: BMY) which has an equity value of approximately $74 billion.
  • MNTech and Elo Touch Solutions resolve multi-patent, multi-venue dispute with 3M regarding touch screen technologyJones Day represented MNTech Co., Ltd. and Elo Touch Solutions, Inc. in a four-patent dispute with 3M regarding touch screen technology.
  • Kakao obtains dismissal of patent infringement action relating to teleconferencing technologyAfter filing a motion to dismiss for lack of personal jurisdiction for Korea-based Kakao Corporation in a patent infringement action involving two patents relating to teleconferencing technology, Jones Day obtained dismissal of the action with prejudice.
  • Kakao patent infringement action relating to voice messaging technology successfully dismissedJones Day successfully defended Kakao Corporation in a patent infringement action involving five patents relating to voice messaging technology.
  • Sewoon obtains dismissal of patent infringement action regarding stent technologyJones Day successfully defended Sewoon Medical Co., Ltd., Standard Sci-Tech Inc., and EndoChoice, Inc. in a patent infringement action regarding stent technology.
  • Taewoong Medical resolves patent infringement dispute over stent technologyJones Day successfully defended Taewoong Medical Co., Ltd. in a patent infringement action regarding stent technology.
  • ToolGen seeks patent protection for CRISPR technologyJones Day is prosecuting patent applications and developing a patent portfolio on behalf of ToolGen, Inc. for CRISPR technology.
  • Celgene develops patent portfolio for use of different polymorphic forms of 5-AZACYTIDINEJones Day assists Celgene Corporation with obtaining patent protection for different polymorphic forms of 5-AZACYTIDINE.
  • Celgene seeks patent protection for different oral formulations of 5-AZACYTIDINEJones Day is prosecuting applications and developing a patent portfolio on behalf of Celgene Corporation for oral formulations of 5-AZACYTIDINE.
  • SOLiD and Reach obtain jury verdict finding non-infringement in competitor-vs.-competitor patent caseFollowing a seven day trial, a jury in the Northern District of California unanimously found that Jones Day clients SOLiD, Inc. and Reach Holdings LLC did not infringe any claims of a 16-year-old wireless communications patent owned by Corning Optical Communications Wireless Ltd., a subsidiary of Corning, Inc.
  • Celgene establishes global patent portfolio for its brands REVLIMID®, POMALYST®, OTEZLA®, VIDAZA®, ABRAXANE® and ISTODAX®Jones Day assists Celgene Corporation in the establishment of its global patent portfolio related to lenalidomide (REVLIMID®), pomalidomide POMALYST®), apremilast (OTEZLA®), azacitidine (VIDAZA®), ABRAXANE® and romidepsin (ISTODAX®) for the treatments of cancer and immune, inflammatory conditions.
  • Hyundai fends off patent infringement actionJones Day successfully represented Hyundai Motor America in a patent infringement suit filed in the Central District of California related to telematic technology.
  • Additional Speaking Engagements

    • April 2018
      IP Infringement Claims at the U. S. International Trade Commission – A Comparison to U.S. District Court Actions
    • January 2018
      U. S. Patent Litigation and Inter Partes Review Proceedings
    • December 2017
      Intellectual Property Protection Of Artificial Intelligence and Big Data Technologies
    • September 2017
      Drafting U.S. Provisional and Non-Provisional Applications; U.S. Patent Litigation, Discovery, Privilege Protection and Inter Partes Review
    • May 2017
      Issues And Strategic Considerations For The Protection and Use Of Artificial Intelligence Technologies
    • September 2016
      U.S. IPR and Patent Prosecution Strategy
    • September 2016
      Global IP Procurement and Enforcement for Pharmaceutical and Biotechnology Inventions
    • June 2016
      Artificial Intelligence Intellectual Property: Players, Issues, and Strategic Considerations
    • January 2016
      IP Enforcement, Discovery & Privilege Issues in the US
    • March 2015
      Television Interview: Jones Day's Global Presence, TV Korea Daily Pharm
    • September 26, 2014
      IP Enforcement in the US: the Jury Trial, Asia Intellectual Property Finance and Business Conference
    • September 22, 2014
      Inter Partes Review in the United States Patent Office; Deposition and Trial Strategies for Witnesses in United States Lawsuits
    • April 2014
      Growing Pharmaceutical & Health Care Business Using Global Patent Strategy
    • April 2014
      U.S. Patent Litigation Guide and Overview of Standard-Essential Patents
    • November 2013
      Post-Grant Proceedings and New Developments in the U.S. - a Year After the 2011 Patent Law (AIA)
    • September 10-13, 2013
      Recent Developments and Uncertainties in the Law on Patent Eligible Subject Matter; Recent Developments in the ITC and Injunctive Relief For Standard-Essential Patents; US Patent Litigation Reform – Legislative Efforts and Practical Strategy Dealing with Non-Practicing Entities
    • September 24-28, 2012
      US Patent Litigation in the Wake of AIA, and Using the New Post-Grant Proceedings; Strategic Decisions Regarding the Upcoming US Move to a First-To-File System; Myriad Case: Patentable Subject Matter
    • October 4-7, 2011
      The 2011 Patent Reform Act
    • June 15, 2010
      Pharmaceutical Polymorphism and U.S. Patent Law: Recent Developments
    • March 2009
      Comparison and Strategy of U.S. ITC Investigation and Patent Infringement Litigation in U.S. District Courts
    • September 2008
      Patent Procurement and Portfolio Management Strategy
    • June 1, 2007
      Intellectual Property Litigation and ITC Litigation in the U.S.A., Korea Drug Research Association
    • May 30, 2007
      Intellectual Property Litigation and ITC Litigation in the U.S.A., Korea Small Business Corporation Association and Korea Intellectual Property Lawyer Association
    • August 15, 2004
      Patent Litigation and U.S. ITC Litigation, LG Cable Co., Ltd.
    • August 14, 2004
      Effective Patent Portfolio, LG Cable Co., Ltd.
    • March 25, 2004
      Developments in the U.S. Doctrine of Equivalents; IP Due Diligence, Korea Drug Research Association
    • May 15, 2003
      Focus on U.S. Patent Litigation;  Patent and Telecommunication Standardization, Korea Telecommunication Technology Association
    • May 27, 2002
      Copyright and Internet, SK Telecom Co., Ltd.
    • May 26, 2002
      Doctrine of Equivalents in the U.S.A., Korean IP Firms
    • May 25, 2002
      Patent Procurement and Litigation in the U.S.A., Hyundai Motor Company and Kia Motor Company