Yoon & Lee International Patent & Law Firm

IAM Research

The Patent 1000 focuses exclusively on patent practice and has firmly established itself as the definitive 'go-to' resource for those seeking world-class legal patent expertise.

Bronze - Firms: litigation

Silver - Firms: prosecution

“Yoon & Lee is simply top notch. It carries out conscientious and competent work for every case.” Founded more than 30 years ago, Yoon & Lee is a reputed patent practice known for its holistic offering, integrity, and the ability to maintain long-lasting relationships with patrons. A large number of the outfit’s 62 IP specialists have technical backgrounds and advanced degrees. The firm serves a diverse range of customers, from multinationals to SMEs, and is especially popular among major electronics companies. With over three decades of IP experience – some of which was spent in the United States – and a background in physics, Byeong-Ok Song has wide expertise encompassing optics, semiconductors and many types of engineering. He heads the inbound mechatronics team. A talented drafter and electrical and electronics virtuoso, Yong-won Lee is the set’s leading expert on 5G patent work. His knowledge further extends to LTE, LTE-A, and 3GPP communication standards. Ji-man Park captains the telecommunications squad and handles prosecution matters for major multinationals. He has ample technical nous from his time as an industrial process analyst and systems designer at a nuclear plant. Professional and very knowledgeable in the patent field, Ji-man is responsive and well informed on the latest legal trends.” Having recently moved to Yoon & Lee from another practice ranked in this chapter, US-qualified former KIPO examiner Seong-Ki Kim focuses on chemistry and biotechnology.

Firm Profile

Yoon & Lee International Patent & Law Firm provides a comprehensive range of services for IP rights, including patents and trademarks, as well as consultation services for the management and enforcement of IP rights. The firm was founded in 1989 and became a limited liability company in 2017. Yoon & Lee offers optimised IP services for the benefit of clients through close cooperation and teamwork that maximises the high levels of expertise and experience of its staff of 86, which includes more than 30 foreign and domestic patent attorneys and lawyers. The firm is particularly well known for its technical expertise and long-term relationships with clients.


The firm’s main specialisation is in patent prosecution, especially in the electronics and software, chemistry and biotech, and mechanical and mechatronics sectors. Although the firm also has strength and expertise in contentious patent issues before both the patent and law courts, its main area of practice for contentious issues is before the patent court; this area of work is relatively small because its success in patent prosecution means there is little need to appeal to the patent court. It employs a high percentage of patent attorneys and technical specialists compared with general law firms and other patent law firms in Korea (32 patent attorneys, 20 patent engineers, and two attorneys-at-law). In particular, the firm offers an efficient and effective combination of patent attorneys (including a partner patent attorney with an LLM from the United States) with extensive careers including substantial court cases before district and high courts, as well as the patent court. The firm’s technical advisers have advanced degrees (PhD and other postgraduate qualifications) in their specialist subjects, including electrical engineering, electronics, communications, computer science, mechanical engineering, chemistry, biotechnology, pharmaceuticals, cosmetics and life sciences. Based on their strong technical knowledge, the firm’s specialists are often called to testify as expert witnesses in court cases.

Areas of expertise

Yoon & Lee has four patent teams:

  • electronics/telecommunications – including electric, electronics, image processing, software, the Internet of Things and artificial intelligence;
  • standard – communications standards (including 5G standard patents);
  • mechanics – including mechanical and mechatronics, optics, software-related inventions, semiconductors, 3D printing, electrical vehicles, and vehicles; and
  • chemistry/biotech – including pharmaceuticals, cosmetics, biotechnology, chemical, and biochemical.


Yoon & Lee provides the following services:

  • worldwide patent application and registration services (Patent Cooperation Treaty applications), worldwide utility model application and registration services, prior art searches, patentability searches, and patent mapping;
  • watching services for foreign patents and publications, patent infringement analysis, patent invalidation analysis, patent invalidation trial and litigation, patent infringement trial and settlement negotiations;
  • licence agreements, assignments, and other agreements involving all forms of IP rights, technology valuation, technology transfer, and contract assistance; and
  • invention mining, providing diverse strategies for planning applications for patent and utility model rights, know-how management and translation services.

Trademarks and designs

Yoon & Lee has a tight-knit trademark and design group that is able to provide excellent and individualised services to all clients. The team is headed by a former trademark examiner at the Korea Intellectual Patent Office. It also includes a US attorney to provide an international perspective and meet the requirements and expectations of international clients and a Korean attorney for local litigation cases. The team delivers a wide range of trademark and design services and acts for businesses, both Korean and from overseas, in all market sectors.


Yoon & Lee has a wide range of clients both in terms of geographical distribution and industrial sector; these clients range from major international companies with established global operations to small and medium-sized enterprises. Unlike in some larger practices, at Yoon & Lee the most experienced professionals, rather than junior staff, handle all cases with all the partner patent attorneys being involved in case work. The firm is able to work in Korean, English and Japanese and provides translation services for these languages, as well as for all languages into/from Korean. Yoon & Lee places great emphasis on client satisfaction by providing quick, accurate and specialised services to meet the individual requirements of clients and to build trust over the long term; this is reflected in the over 25-year long relationships the firm enjoys with major Korean and foreign companies.

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