Defenses of Defendant

Invalidity Defense

It is well settled that in case the patented invention lacks novelty over the prior art, the patent is unenforceable. Even before the patent has been invalidated through the separate invalidity proceeding, the patent shall be regarded as being void.

As for non-obviousness challenge within an infringement lawsuit under bifurcated system, the Supreme Court has maintained their firm position for a long time that the patent is enforceable before the invalidity based on the ground of being obvious over the prior art. However, the Supreme Court changed their position through en banc decision in 2012. Therefore, a defendant raise an affirmative defense based on obviousness of the patented invention.

The Korean Supreme Court en banc decision in 2012 is that in principle, (1) an issued patent is presumed to be valid; (2) an infringement court may not decide the validity of a patent; (3) arguing invalidity of a patent in suit shall not be a defense in an infringement action; but, as detour as a practical solution, (4) in case the patent in suit is clearly to be invalid due to lack of inventive step as well as lack of novelty, it is an abuse of patent right to seek the injunction and damages based on the patent. Therefore, in order to determine such abuse of a patent right, the infringement court may examine the validity of a patent due to lack of inventive step as well as lack of novelty.

As for standard of proof, presumption of validity is not strong. The challenger can meet his burden by preponderance of evidence, not by clear and convincing. For example, obviousness arguments will be in favor of invalidity where there is inevitable combination, no synergistic effect from combination, no unexpected result.

Other Affirmative Defense

An accused infringer may assert that his practice falls in the scope of publicly known technology in which he is entitled to freely use it. Under the Korean patent law, it might be a mirror image of obviousness arguments.

Further, prosecution history estoppel, experimental use, pharmaceutical clinical test, prior user right, intervening right can be used as defense. For instance, the patent right does not extend to acts done for experimental purposes relating to the subject matter of the patented invention. Further, clinical tests for the purpose of KFDA approval of generics does not infringe a patent right. Unlike the U.S. patent law, a declaratory judgment or inequitable conduct before the PTO defense is not available.

Defendant’s Motion Practice: Deposit Cost in Advance

When a plaintiff is a foreigner having neither a residence nor a business office in Korea, a defendant can file a motion that the plaintiff has to deposit the cost of suit in advance. In this situation, a defendant is not required to respond to a plaintiff’s complaint until a plaintiff deposits the estimated cost of the lawsuit. If the foreign party does not deposit by the date the court specifies, the court may dismiss the suit. In the case where the plaintiff is a foreigner and the defendant is a Korean, the Korean defendant usually file this motion to obtain enough time for considering defense and counterclaim. The foreign party may deposit a bond.

Cease and Desist Letter – Warning Letter

When a patentee finds his patent right being infringed by a third party, he may send an alleged infringer a cease and desist letter. It is to warn the infringer of legal responsibilities and demand the cessation of infringement activities. Furthermore, the accused infringer, at least from the day of receiving the warning letter, will not be able to deny his intent or negligence in the infringement activities.

This warning letter plays an important role in proving the claim of damage compensation as well as the criminal liability for infringement. For criminal action, it is required to prove the intent of an infringer regarding infringing acts of a patent without doubt. In particularly, infringer’s intent in the infringement shall not be presumed even if a patent marking is present on the patented product. With a warning letter, it is easy and convenient to prove the infringer’s intent beyond reasonable doubt. Therefore, a patentee has often sent warning letters to infringers to point out the ownership of the patent and their infringing activities.

Patent Marking

A patentee may obtain a preliminary or permanent injunction against infringers without patent marking. Unlike the injunction remedy, however, the patentee must prove the intent or negligence of infringers in order to obtain damage compensation from the infringers. There are several ways to prove intent or negligence of an infringer. Patent Marking is not required but really effective and convenient in proving the intent or negligence of infringers. The Korean Patent Act allows patent marking on a container or packages, and there is no specific format required. For a process-patent marking, the patentee should specifically indicate that the patent is a process patent, e.g., "Korean Process Patent No. xxx."

Indirect Infringement - Contributory Infringement

Korea does not have inducement clause within the Korean Patent Act. Thus, an inducement is outside the indirect infringement stipulations under the patent law. However, if one actively induced someone to infringe the third party patent, the active inducer might assume responsibilities for torts under civil law.

There is a specific provision regarding contributory infringement in the Korean Patent Act. Section 127 of the Patent Act stipulates that the act to make or use a non-staple part to construct a patented invention can amount to infringement of a patent right. According to the Supreme Court, a patentee assumes burden to prove that an alleged product is only for practicing the patented invention and is non-staple. In case the accused person is found to have knowledge of infringing behavior; commits a contributory act for direct infringement; and the accused product has no substantial non-infringing uses of the accused products, the accused person is liable for contributory infringement. The liability is the same as a direct infringement.

Criminal Sanction on IPR Infringer

Criminal Sanction on IPR Infringer

Infringement of IP is a crime of trespass of personal property. An infringer may be punished up to 7 years in imprison and/or about US$100,000 fine. It is not uncommon that infringers of IP rights, especially trademarks and trade secrets, have been punished under the Korean criminal law.

To prosecute an infringer of IPR as criminal, an accusation by a proprietor is required. According to the Criminal Procedure Act, the proprietor must accuse an infringer within six months of the date of knowing the infringement and the criminal. The beginning point of the limitation starts from the moment of infringement. Also, the accusation to an infringer will be effective to a corporation as a vicarious liability. An infringer of IPR has been often prosecuted in Korea.

Vicarious Liability on Company

The Patent Act stipulates that the court can punish not only a person who committed an infringement but also a legal entity by imposing fines. The separate accusation against a legal entity is not required because it is not a separate crime from the personal infringer’s. The Supreme Court held that even if the patentee’s request applies only to a person, not to the legal entity, the legal entity may be punished without the expressed accusation of the patentee. This is because the legal entity is liable for the infringement done by its employee.