Patent Infringement

The act of practicing a patented invention as a business without the permission of the patent holder, a legal issue to which civil, criminal, and administrative remedies and standards of judgment such

Patent Infringement

Overview

Patent infringement refers to the act of practicing the technical idea of a patented invention without the permission of the patent holder and without legitimate title. Since a patent right is a right that monopolizes certain acts of practice, such as producing, using, transferring, leasing, or importing a product, or using a process, infringement is established when a third party performs an act of practice falling within the scope of that right. If infringement is found, the infringer bears civil liability, including claims for injunction and damages, and in cases of willful infringement may be subject to criminal punishment and punitive damages.

Key Details

Requirements for Establishing Infringement

For patent infringement to be established, the following requirements must be met: ① a patent right must exist that is validly registered and within its term, ② the defendant must practice the patented invention, ③ the practice must be conducted as a business (業), and ④ the practiced invention must fall within the scope of the claims. Personal or household practice, or practice for experimental or research purposes, is in principle not regarded as infringement.

Types of Infringement

Direct infringement is where the infringer practices the patented invention as it is; if it is literally encompassed when compared with the claim language, it is literal infringement, and if it differs from the language but falls within an equivalent scope, it is infringement under the doctrine of equivalents. Indirect infringement is the act of producing, transferring, leasing, importing, or storing, as a business, articles used only for practicing the patented invention, and Article 127 of the Patent Act regulates it by distinguishing between articles exclusively used for the invention and those not exclusively used. In addition, issues arise regarding utilization/conflict relationships where an earlier patent and a later patent overlap, the use of process patents, and the transfer of products obtained by such processes.

Standards for Determining Infringement

The basic principle for determining infringement is the all-elements rule, under which infringement occurs only when all elements recited in the claims are present in the accused product. If even one is missing, it is in principle not infringement. Infringement under the doctrine of equivalents is recognized when ① the principle for solving the problem is the same, ② the substituted element would have been obvious to a person of ordinary skill in the art, and ③ the substitution achieves substantially the same effect as the patented invention. However, the doctrine of equivalents is limited when the technology constitutes freely available technology, when the element was consciously excluded by the applicant during prosecution, or when prosecution history estoppel applies.

Grounds for Defense

The defendant may contest the right itself through a patent invalidation trial or a scope confirmation trial, or assert legitimate title such as a prior user right, ordinary license, or exclusive license. In addition, various defenses are used, such as abuse of rights, exhaustion under a license agreement, freely available technology, prosecution history estoppel, and concurrence with product liability. Recently, there is a broad trend of recognizing injunctions based on patents whose invalidity grounds are clear as an abuse of rights.

Remedies

In civil terms, the right to claim an injunction and the right to claim damages are central. The amount of damages is calculated under Article 128 of the Patent Act based on the product of the quantity of products transferred by the infringer and the profit per unit, the infringer's profit, the amount equivalent to a reasonable royalty, and the portion exceeding production capacity, and for willful infringement, punitive damages of up to three times the amount are possible. Other issues include measures for restoring reputation and concurrence with trade secret infringement under the Unfair Competition Prevention Act. Criminally, imprisonment of up to seven years or a fine of up to 100 million won may be imposed. Administratively, investigations by the Korea Trade Commission into unfair trade practices and customs clearance suspension procedures by the Korea Customs Service are utilized.

International Aspects

Because patent rights take effect in each country of registration under the principle of territoriality, infringement determinations and litigation proceed separately by country. In the United States, the federal district courts and ITC Section 337 investigations, and in Europe, the Unified Patent Court (UPC), launched in June 2023, have emerged as centers of cross-border disputes. In China, infringement litigation has surged around the intellectual property courts, and disputes over standard-essential patents (SEPs) and FRAND royalties are expanding worldwide.

Recent Trends

Since the launch of the Unitary Patent and the UPC in June 2023, in 2024–2025 UPC rulings have been accumulating and the structure of European patent litigation is being reorganized. In the United States, following the Supreme Court's decision in Amgen v. Sanofi, there has been a continuing trend of strict application of the claim definiteness requirement, and large-scale patent litigation such as VLSI v. Intel and the activities of non-practicing entities (NPEs) continue in the semiconductor and telecommunications sectors. The U.S. Department of Justice and the Patent and Trademark Office revised their SEP-related policy statement and reorganized the norms for FRAND negotiations, and the EU is discussing a draft SEP regulation.

In Korea, the Korean Intellectual Property Office was elevated to the Intellectual Property Office in October 2024, strengthening its role as the control tower for intellectual property policy, and amendments to the Patent Act in 2024–2025 expanded and refined the scope of application of punitive damages and the method of calculating damages. Discussions of infringement surrounding generative AI training data and the attribution of rights to AI inventions, global patent disputes in the battery, bio, and semiconductor sectors, and complex litigation combining trade secret infringement and patent infringement have become major trends. Companies are making patent portfolio management, freedom-to-operate (FTO) analysis, and license negotiations the core of their defense strategies.