Supreme Court en banc Decision 2010Da95390 Decided January 19, 2012: can invalidity be raised as a defense in Korean patent infringement litigation?

Chanjoong Kim, Partner · Published 13 November 2026

Last verified 9 October 2026

The case

The content of this table is taken from the written judgment. [1]

The issue: can the infringement court look at inventive step before a trial decision for invalidation becomes final and conclusive?

In Korea, the procedure that invalidates a patent is a trial for invalidation before the Intellectual Property Trial and Appeal Board (IPTAB) (특허심판원) (Patent Act, Arts. 132-16 and 133). An interested party or an examiner files the petition for a trial for invalidation. When a trial decision invalidating the patent becomes final and conclusive, the patent right is deemed never to have existed (Art. 133(1) and (3)). [12] [18]

Patent infringement litigation is civil litigation before a court. The patentee claims an injunction against the infringement and damages (Patent Act, Arts. 126 and 128). [12] The issue was the relationship between the two procedures. The dispute was whether the court in the patent infringement litigation can refuse the claim on the ground of lack of inventive step before a trial decision for invalidation becomes final and conclusive. [1]

Earlier precedents separated novelty from inventive step. The 1992 order treated separately the case where the invention lacks novelty because it was public knowledge or in public use at the time of filing. For that case, it held that the scope of the right cannot be recognized, whether or not there is a trial decision for invalidation. The case where the invention has novelty but lacks inventive step was different. The order held that a court cannot deny the scope of the right as a matter of course in other litigation. [2] The 2001 decision held to the same effect for a utility model. [3]

In this case, the plaintiff, who was the patentee, filed the action on the basis of two patents. The claims were an injunction against infringement, destruction of the infringing products, and damages. The lower court, the Seoul High Court, found it clear that the patents would be invalidated because the inventive step of the patent claims at issue was denied. The lower court held that the plaintiff’s claims were an abuse of rights and were not allowed. [1]

What the court held 1: if it is clear that the patent will be invalidated, the claim is an abuse of rights

The Supreme Court first confirmed the principle. The principle is the same even where a registered patent has the ground for invalidation of lack of inventive step. Unless a trial decision for invalidation becomes final and conclusive, the patent, the court said, “does not become invalid” as against everyone. [1]

The Supreme Court then gave two reasons. The first is the purpose of the Patent Act. Article 29(2) of the Patent Act places an invention without inventive step in the “public domain”, which anyone can use freely. Giving the patentee a monopoly over such technology harms the public interest and is contrary to the legislative purpose of the Patent Act. The second is equity. If the claim is allowed merely because an invention without inventive step is formally registered, the patentee obtains an unjust benefit. A person who works (practices) the invention suffers an unreasonable loss. [1]

The standard that the Supreme Court set is as follows. [1]

The Reference Provisions of the written judgment include Article 2 of the Civil Act. [1] Article 2(2) of the Civil Act provides that no abuse of rights is permitted. [14]

The Supreme Court overruled the 1992 order and the 2001 decision. What it overruled is the part holding that, even where inventive step is lacking, a court cannot deny the scope of the right as a matter of course in patent infringement litigation. The extent is “to the extent they are inconsistent with this Opinion”. [1]

What the court held 2: in this case it could not be said to be clear

Even after setting this standard, the Supreme Court reversed the lower judgment. For one claim, the lower court had found it clear that inventive step would be denied on the basis of three pieces of prior art. The Supreme Court decided differently. [1]

The Supreme Court compared the elements of that claim with the prior art one by one. It found that some elements were disclosed as they are in the prior art. It found that there was no particular difficulty in adopting some other elements from the prior art. The one remaining element was different. The Supreme Court found that the technical idea of that element was neither disclosed nor suggested in the prior art. [1]

The Supreme Court viewed the claim as a whole in which the individual elements are organically combined. Viewed in that way, it held, difficulty of the technical configuration and a remarkable effect are recognized. It therefore held that it could not be said to be clear that the patent would be invalidated, and that the plaintiff’s claim was not an abuse of rights. [1]

In this decision, the abuse of rights defense was not accepted. The Supreme Court did not separately define what a “clear case” is. It also gave no example of “special circumstances”. [1]

What the court held 3: the trial decision for correction and the scope of the reversal

The reasoning for the remaining claims was different. The plaintiff filed a petition for a trial for correction. On 21 July 2011, after the lower judgment was rendered, a trial decision correcting those claims was issued, and it became final and conclusive around that time. [1]

The Supreme Court held that the patent application and the registration of the grant of a patent (registration of establishment of a patent right) must be deemed to have been made according to the specification as corrected. It found that the lower judgment, which had decided on the invention before the correction, had the ground for retrial in Article 451(1), subparagraph 8 of the Civil Procedure Act (민사소송법). [1] The ground for retrial in this subparagraph is where an administrative disposition on which the judgment was based has been altered by a different administrative disposition. [15]

The Supreme Court reversed the lower judgment in its entirety. The reason is that, for a judgment that dismisses all of the claims joined in the alternative, the whole judgment must be reversed even if the final appeal is well founded for only some of the claims. [1]

The 2020 en banc decision held that a trial decision for correction that becomes final and conclusive after the closure of pleadings of fact-finding proceedings is not a ground for retrial. [6] This is covered under “Before and after this decision” below.

What the court did not decide

• Whether there was infringement. The Supreme Court did not decide whether the defendant’s products fall within the scope of protection of the patented inventions. [1]
• Grounds for invalidation other than inventive step. The requirement stated in this decision is the case where inventive step is denied. A defense based on novelty or on the description requirements for the specification was not a subject of this decision. [1]
• The result after the remand. The judgment of the Seoul High Court after the remand could not be confirmed.

Before and after this decision: earlier precedents, later decisions, and later changes in the law

Decisions before and after this decision

The 2004 decision used the framework of abuse of rights first. The wording of that decision is “ground for invalidation”, and it was not limited to inventive step. [4] The 2012 en banc decision did not cite the 2004 decision. [1]

Did later decisions change this decision?

The standard for the abuse of rights defense has not changed. The case search of the Ministry of Government Legislation (법제처) showed no en banc decision that overruled this standard (searched on 9 October 2026). In the decision of 30 January 2020, the lower court had found it clear that the patent would be invalidated because inventive step was denied. As an additional determination, the lower court had rejected the claim based on that patent right as an abuse of rights. The Supreme Court held that there was no error in this determination. [11]

The 2014 en banc decision drew a line on the scope of application. The Majority Opinion held that, in a trial to confirm the scope of a right, the scope of the right must not be denied on the ground that inventive step is denied. It held that, where the patent was public knowledge or in public use at the time of filing, the scope of the right can be denied in a trial to confirm the scope of a right as well. There was a Dissenting Opinion by two Justices. The Dissenting Opinion applied the reasoning of the 2012 decision to the trial to confirm the scope of a right. It stated that, if it is clear that the patent will be invalidated for lack of inventive step, there is no interest in claiming the trial. In its opinion, such a petition is unlawful and must be dismissed. [5]

Not every way of using prior art in a trial to confirm the scope of a right is closed. The 2017 decision dealt with the case where the accused invention is free-to-work technology. This is the case where the accused invention consists only of publicly known art, or where a person skilled in the art could easily work it from publicly known art. In this case, the accused invention does not fall within the scope of the right, with no need to compare it with the patented invention. The Supreme Court held that this legal principle also applies where there is literal infringement. [17]

The part on correction is in a different position. The Majority Opinion of the 2020 en banc decision held that there is no ground for retrial even if a trial decision for correction becomes final and conclusive after the closure of pleadings of fact-finding proceedings. That case was an action requesting revocation of a decision rendered by the IPTAB (legal proceedings against trial rulings) in a trial for invalidation. The Majority Opinion stated that this legal principle must apply in the same way to civil litigation based on infringement of a patent right. There was a Concurring Opinion by two Justices. [6]

The 2020 decision named the decisions that it overruled. For patent infringement litigation, it named the 2004 decision. The 2012 en banc decision is not among those names. However, the 2020 decision stated that it overrules all “decisions to the same effect” to the extent they are inconsistent. [6]

What the 2020 decision overruled is the decisions to the effect that a trial decision for correction that became final and conclusive is a ground for retrial under Article 451(1), subparagraph 8 of the Civil Procedure Act. [6] The 2012 decision treated a trial decision for correction that became final and conclusive after the lower judgment was rendered as a ground for retrial under that very subparagraph. [1] This part of the 2012 decision therefore falls within the “decisions to the same effect” that the 2020 decision overruled. The standard for the abuse of rights defense is not a subject of the overruling.

The 2020 decision also dealt with correction in patent infringement litigation. Where an abuse of rights defense is raised, the patentee can raise a counter-defense (재항변). The counter-defense is that the ground for invalidation has been cured, or can be cured, by a petition for a trial for correction or by a request for correction. If the patentee did not raise this counter-defense, the patentee cannot contest the determination made in the fact-finding proceedings on the ground of a trial decision for correction that became final and conclusive after the closure of pleadings of fact-finding proceedings. [6]

There is also a decision on another ground for invalidation. In the 2022 decision, the lower court had found that the patent should be invalidated because the claims were not clear. The lower court had therefore held that the exercise of the patent right was an abuse of rights. The Supreme Court held that it was difficult to find that those claims failed to meet the description requirements. The Supreme Court reversed the part of the lower judgment on the claim for relief concerned. This 2022 decision did not state a general standard for an abuse of rights defense based on a failure to meet the description requirements. [10]

Has the law applied by the decision changed since then?

The articles are in the same place. The wording and the jurisdiction have changed.

• Article 29(2) of the Patent Act. The wording at the time of the decision was that a person skilled in the art “용이하게 발명할 수 있는 것” (an invention that the person could easily make). [13] The current wording is “쉽게 발명할 수 있으면” (if the person could easily make the invention). [12] The changed wording entered into force on 1 January 2015 under Act No. 12753. Article 8 of the Addenda to this Act makes the former provisions apply to patent applications filed before the enforcement date and to the examination and trials of those patent applications. [13]
• Article 133 of the Patent Act. The grounds on which a petition for a trial for invalidation can be filed include a violation of Article 29, at the time of the decision and at present. It is also the same that the patent right is deemed never to have existed when a trial decision for invalidation becomes final and conclusive. [12] [13] The petitioner has changed. The proviso to Article 133(1) at the time of the decision set a period in which any person could file a petition for a trial for invalidation. The period ran from the date of registration until three months after the date of publication of registration, and the ground in subparagraph 2 was excluded. [13] Act No. 14035 deleted this proviso and newly introduced the request for revocation of a granted patent (특허취소신청) (Art. 132-2). This Act entered into force on 1 March 2017. Any person can file a request for revocation of a granted patent from the date of registration until the date six months after the date of publication of registration. The provisions on the request for revocation of a granted patent apply from patent rights registered on or after the enforcement date (Addenda, Art. 10). The petitioner in a trial for invalidation of a patent right registered before the enforcement date is governed by the former provisions (Addenda, Art. 21). [18]
• Articles 126 and 128 of the Patent Act. The right to seek an injunction against infringement in Article 126(1) has the same content at the time of the decision and at present. [12] [13] At the time of the decision, Article 128 had the title “Presumption, etc. of the Amount of Damages” (손해액의 추정등) and provided for the calculation and presumption of the amount of damages. [13] The current Article 128(1), which provides that damages can be claimed, was newly inserted by Act No. 14112. This Act entered into force on 30 June 2016. [18]
• The provision on the effect of a correction. At the time of the decision, it was Article 136(8) of the Patent Act. For one of the patents, the Supreme Court applied Article 136(9) as it stood before the amendment by Act No. 6411 of 3 February 2001. [1] At present, it is Article 136(10). The paragraph number was changed by Act No. 14035, and this Act entered into force on 1 March 2017. [12] [13]
• Jurisdiction over the appeal. The lower court in this case was the Seoul High Court. [1] The current Article 24(2) of the Civil Procedure Act sets the jurisdiction over actions concerning intellectual property rights such as patent rights. Exclusive jurisdiction lies with the district court located at the seat of the high court that has jurisdiction over the location of the court competent under the general provisions. The district court located at the seat of the Seoul High Court is limited to the Seoul Central District Court. Under paragraph (3) of the same Article, a party can also file the action with the Seoul Central District Court. [15] The appeal in those cases is judged by the Intellectual Property High Court of Korea (Patent Court of Korea) (특허법원) (Court Organization Act (법원조직법), Art. 28-4, subparagraph 2). [16]

The jurisdiction provisions entered into force on 1 January 2016. The amended provisions of the Civil Procedure Act apply from cases in which the complaint is first received after the Act enters into force (Addenda to Act No. 13521, Art. 2). [15] Article 28-4, subparagraph 2 of the Court Organization Act also applies in some cases that were pending before the enforcement date. These are the cases in which the judgment of first instance is rendered after the Act enters into force (Addenda to Act No. 13522, Art. 2). [16]

The provision for patent infringement litigation and a trial for invalidation that proceed together is Article 164 of the Patent Act. Where necessary in litigation, a court can suspend the legal proceedings. The suspension can last until a decision on a request for revocation of a granted patent or a trial decision on the patent becomes final and conclusive. The court can do so ex officio or at the request of a party (Art. 164(2)). When an action on infringement is filed, the court must notify the President of the Intellectual Property Trial and Appeal Board to that effect. When a petition for a trial for invalidation, etc. is filed in response to that action, the President of the Intellectual Property Trial and Appeal Board must notify the court (Art. 164(3) and (4)). [12]

The amended Patent Act (Act No. 21955) enters into force on 16 March 2027. This amendment does not change Articles 1, 29, 126, 128, 133, 136 or 164. [12] The amended Civil Procedure Act (Act No. 21455), which enters into force on 1 March 2028, does not change Article 24(2) or (3). [15] The amended Court Organization Act that enters into force in 2028 also does not change Article 28-4. [16]

How far inventive step can be contested in each procedure

The procedure of a trial for invalidation is covered in “How does a trial for invalidation work in Korea?“. The trial to confirm the scope of a right is covered in “What is a trial to confirm the scope of a right in Korea?”. Correction is covered in “How can a granted Korean patent be corrected?”. The standard for determining inventive step is in “What is the inventive step standard under Article 29(2) of the Korean Patent Act?“.

What changes in practice

The following is the opinion of DEFINE IP Law Firm. The response in an individual case depends on the facts, so please confirm with your agent.

• In general, we suggest that a party that receives an infringement claim consider the abuse of rights defense and a trial for invalidation together. Even if the defense is accepted, the patent is not invalid as against everyone. The procedure that makes the patent right deemed never to have existed is a trial for invalidation.
• The requirement for the defense is a “clear case” that the patent will be invalidated. In this decision too, the lower court’s finding that it was clear was overturned at the Supreme Court. When contesting inventive step by a combination of prior art, we suggest first checking whether every element of the claim is disclosed or suggested in the prior art.
• In a trial to confirm the scope of a right, the argument that the inventive step of the patented invention is denied is not accepted. We suggest reflecting this point in the plan. Prior art can be used for the argument that the accused invention is free-to-work technology.
• We suggest that a patentee check again the inventive step of the claims to be asserted before filing an action. If a correction is needed, we suggest asserting it as a counter-defense of correction before the closure of pleadings of fact-finding proceedings. The 2020 en banc decision dealt with a patentee who did not raise the counter-defense of correction. That patentee cannot contest the determination made in the fact-finding proceedings on the ground of a trial decision for correction that became final and conclusive after the closure of pleadings.
• We suggest that a company that conducts patent infringement litigation in Korea together with litigation in other countries reflect the appellate court in its schedule. The appeal in patent infringement litigation is judged by the IP High Court of Korea.

FAQ

Can a Korean court in patent infringement litigation invalidate a patent?

No. The Supreme Court held that the patent is not invalid as against everyone unless a trial decision for invalidation becomes final and conclusive. The court deliberates and decides on inventive step as a premise for determining the propriety of the abuse of rights defense. [1]

Can a defendant raise only the defense in patent infringement litigation, without filing a petition for a trial for invalidation?

This decision held that the defense can be raised even before a trial decision for invalidation becomes final and conclusive. The requirements stated in the written judgment do not include that a petition for a trial for invalidation must have been filed. [1]

Can the abuse of rights defense also be based on a ground for invalidation other than inventive step?

The standard set in this decision concerns the case where inventive step is denied. [1] The 2004 decision wrote more broadly of the case where a “ground for invalidation” is evident. [4] There are separate decisions for trademarks and designs. [7] [8]

Can lack of inventive step also be argued in a trial to confirm the scope of a right?

According to the Majority Opinion of the 2014 en banc decision, the scope of the right cannot be denied by that argument. Where the patent was public knowledge or in public use at the time of filing, the scope of the right can be denied. [5] The argument that the accused invention is free-to-work technology can be made. [17]

Does patent infringement litigation stop until the result of the trial for invalidation is issued?

It does not stop automatically. Where necessary, the court can suspend the legal proceedings until a decision on a request for revocation of a granted patent or a trial decision on the patent becomes final and conclusive (Patent Act, Art. 164(2)). [12]

How DEFINE IP Law Firm handles this

When DEFINE IP Law Firm receives an inquiry about an infringement claim, we review a trial for invalidation and the abuse of rights defense in patent infringement litigation side by side. We organize the prior art for contesting inventive step by comparing it with each element of the claim. We do not present as the standard of a decision anything that is not in the written judgment. For questions about invalidity arguments against Korean patents and responses to infringement claims, please write to contact@defineip.kr.

Sources

1. Supreme Court of Korea (대법원), Supreme Court en banc Decision 2010Da95390 Decided January 19, 2012 (대법원 2012. 1. 19. 선고 2010다95390 전원합의체 판결). https://www.law.go.kr/판례/(2010다95390) (verified 9 October 2026)
2. Supreme Court of Korea, Supreme Court Order 91Ma540 Dated June 2, 1992 (대법원 1992. 6. 2. 자 91마540 결정). https://www.law.go.kr/판례/(91마540) (verified 9 October 2026)
3. Supreme Court of Korea, Supreme Court Decision 98Da7209 Decided March 23, 2001 (대법원 2001. 3. 23. 선고 98다7209 판결). https://www.law.go.kr/판례/(98다7209) (verified 9 October 2026)
4. Supreme Court of Korea, Supreme Court Decision 2000Da69194 Decided October 28, 2004 (대법원 2004. 10. 28. 선고 2000다69194 판결). https://www.law.go.kr/판례/(2000다69194) (verified 9 October 2026)
5. Supreme Court of Korea, Supreme Court en banc Decision 2012Hu4162 Decided March 20, 2014 (대법원 2014. 3. 20. 선고 2012후4162 전원합의체 판결). https://www.law.go.kr/판례/(2012후4162) (verified 9 October 2026)
6. Supreme Court of Korea, Supreme Court en banc Decision 2016Hu2522 Decided January 22, 2020 (대법원 2020. 1. 22. 선고 2016후2522 전원합의체 판결). https://www.law.go.kr/판례/(2016후2522) (verified 9 October 2026)
7. Supreme Court of Korea, Supreme Court en banc Decision 2010Da103000 Decided October 18, 2012 (대법원 2012. 10. 18. 선고 2010다103000 전원합의체 판결). https://www.law.go.kr/판례/(2010다103000) (verified 9 October 2026)
8. Supreme Court of Korea, Supreme Court Decision 2016Da219150 Decided September 28, 2018 (대법원 2018. 9. 28. 선고 2016다219150 판결). https://www.law.go.kr/판례/(2016다219150) (verified 9 October 2026)
9. Supreme Court of Korea, Supreme Court Decision 2010Da42082 Decided July 12, 2012 (대법원 2012. 7. 12. 선고 2010다42082 판결). https://www.law.go.kr/판례/(2010다42082) (verified 9 October 2026)
10. Supreme Court of Korea, Supreme Court Decision 2019Da277751 Decided January 27, 2022 (대법원 2022. 1. 27. 선고 2019다277751 판결). https://www.law.go.kr/판례/(2019다277751) (verified 9 October 2026)
11. Supreme Court of Korea, Supreme Court Decision 2017Da227516 Decided January 30, 2020 (대법원 2020. 1. 30. 선고 2017다227516 판결). https://www.law.go.kr/판례/(2017다227516) (verified 9 October 2026)
12. Patent Act (특허법), Act No. 21134, in force from 11 November 2025. Articles 1, 29, 126, 128, 132-16, 133, 136 and 164. The same Articles of the Patent Act, Act No. 21955, promulgated on 15 September 2026, in force from 16 March 2027. https://www.law.go.kr/법령/특허법 (verified 9 October 2026)
13. Patent Act (특허법), Act No. 10716, in force from 1 July 2011 (the version at the time the decision was rendered). Articles 29, 126, 128, 133 and 136. Patent Act, Act No. 12753, promulgated on 11 June 2014, in force from 1 January 2015, Addenda, Art. 8. Patent Act, Act No. 14035, promulgated on 29 February 2016, in force from 1 March 2017, Article 136. Version history at https://www.law.go.kr/법령/특허법 (verified 9 October 2026)
14. Civil Act (민법), Act No. 21454, in force from 17 March 2026. Article 2. https://www.law.go.kr/법령/민법 (verified 9 October 2026)
15. Civil Procedure Act (민사소송법), Act No. 21993, in force from 2 October 2026. Article 24, Article 451(1), subparagraph 8, and Article 2 of the Addenda (Act No. 13521, promulgated on 1 December 2015, in force from 1 January 2016). Article 24 of the Civil Procedure Act, Act No. 21455, promulgated on 17 March 2026, in force from 1 March 2028. https://www.law.go.kr/법령/민사소송법 (verified 9 October 2026)
16. Court Organization Act (법원조직법), Act No. 22054, in force from 2 October 2026. Article 28-4 and Article 2 of the Addenda (Act No. 13522, promulgated on 1 December 2015, in force from 1 January 2016). https://www.law.go.kr/법령/법원조직법 (verified 9 October 2026)
17. Supreme Court of Korea, Supreme Court Decision 2016Hu366 Decided November 14, 2017 (대법원 2017. 11. 14. 선고 2016후366 판결). https://www.law.go.kr/판례/(2016후366) (verified 9 October 2026)
18. Patent Act (특허법), Act No. 14112, promulgated on 29 March 2016, in force from 30 June 2016, Article 128. Patent Act, Act No. 14035, promulgated on 29 February 2016, in force from 1 March 2017, Articles 132-2, 133 and 164, and Addenda, Arts. 10 and 21. Patent Act, Act No. 21134, in force from 11 November 2025, Articles 132-2 and 132-16. Version history at https://www.law.go.kr/법령/특허법 (verified 9 October 2026)