Open Decision Ledger · IP, data & telecommunications
Core of the technical idea and the three elements of equivalence
Supreme Court, Feb. 14, 2019, 2015Hu2327 (judgment)
No holding summary · checked against points at issue. The official text publishes no summary of the holding for this decision. The quotation and factors in this record are copied verbatim from the points at issue; the evidence for each axis is taken from the points at issue, the order and the reasons.
Case name: 권리범위확인(특)
Official text on the National Law Information Center
Question
Where a subject invention differs from part of the configuration described in the claims of a patented invention, when does it still fall within the scope of rights as equivalent to that configuration, and how is it decided whether the two share the same problem-solving principle?
Holding
The subject invention remains within the scope of rights, unless special circumstances exist, when it shares the same problem-solving principle as the patented invention, produces substantially the same function and effect, and the modification is of a degree that any person with ordinary knowledge in the technical field could readily have conceived. To decide whether the problem-solving principle is the same, the Court does not formally extract part of the claimed configuration, but ascertains in substance, with the description in the specification and the state of the art at the filing date taken into account, what the core of the technical idea is on which the means unique to the patented invention rests in contrast to the prior art. Whether the function and effect are substantially the same is judged chiefly by whether the subject invention too solves the technical problem that the patented invention solved; where that core is embodied in the accused product the effects are substantially the same in principle, and where the core was already public at the filing date or was no different from it, the individual functions and roles of the elements concerned are compared.
Points at issue, verbatim
확인대상 발명에서 특허발명의 특허청구범위에 기재된 구성 중 변경된 부분이 있는 경우, 확인대상 발명이 특허발명의 특허청구범위에 기재된 구성과 균등한 것으로서 특허발명의 권리범위에 속한다고 볼 수 있는 요건 및 확인대상 발명과 특허발명의 ‘과제 해결원리가 동일’한지 판단하는 방법
Unofficial English translation
The requirements for the invention to be confirmed, where it has portions of the elements recited in the claims of the patented invention modified, to be regarded as belonging to the scope of the patent right as equivalent to the elements recited in the claims of the patented invention, and the method of determining whether the invention to be confirmed and the patented invention have 'the same principle of solving the problem'
Disposition
Reversed and remanded Stated in the decision
원심판결을 파기하고, 사건을 특허법원에 환송한다.
Unofficial English translation
The judgment of the court below is reversed, and the case is remanded to the Patent Court.
Form of the test
Elements stated Stated in the decision
확인대상 발명에서 특허발명의 특허청구범위에 기재된 구성 중 변경된 부분이 있는 경우에도, 특허발명과 과제 해결원리가 동일하고, 특허발명에서와 실질적으로 동일한 작용효과를 나타내며, 그와 같이 변경하는 것이 그 발명이 속하는 기술분야에서 통상의 지식을 가진 사람이라면 누구나 쉽게 생각해 낼 수 있는 정도라면, 특별한 사정이 없는 한 확인대상 발명은 특허발명의 특허청구범위에 기재된 구성과 균등한 것으로서 여전히 특허발명의 권리범위에 속한다고 보아야 한다.
Unofficial English translation
Even where the invention to be confirmed has portions of the elements recited in the claims of the patented invention modified, if the invention to be confirmed has the same principle of solving the problem as the patented invention, exhibits substantially the same function and effect as in the patented invention, and such modification is at a level that could be readily conceived of by anyone having ordinary knowledge in the technical field to which the invention pertains, then, absent special circumstances, the invention to be confirmed must be regarded as being equivalent to the elements recited in the claims of the patented invention and as still belonging to the scope of the patent right.
Factors
- 확인대상 발명에서 특허발명의 특허청구범위에 기재된 구성 중 변경된 부분이 있는 경우
- 확인대상 발명이 특허발명의 특허청구범위에 기재된 구성과 균등한 것으로서 특허발명의 권리범위에 속한다고 볼 수 있는 요건 및 확인대상 발명과 특허발명의 ‘과제 해결원리가 동일’한지 판단하는 방법
- 발명의 상세한 설명의 기재와 출원 당시의 공지기술 등을 참작하여 파악되는 특허발명에 특유한 해결수단이 기초하고 있는 기술사상의 핵심이 침해제품 등에서도 구현되어 있는 경우, 작용효과가 실질적으로 동일한지 여부(원칙적 적극)
- 기술사상의 핵심이 특허발명의 출원 당시에 이미 공지되었거나 그와 다름없는 것에 불과한 경우, 작용효과가 실질적으로 동일한지 판단하는 방법
Unofficial English translation
• Where the invention to be confirmed has portions of the elements recited in the claims of the patented invention modified
• The requirements for the invention to be confirmed to be regarded as belonging to the scope of the patent right as equivalent to the elements recited in the claims of the patented invention, and the method of determining whether the invention to be confirmed and the patented invention have 'the same principle of solving the problem'
• Where the core of the technical idea, on which the means for solving the problem unique to the patented invention as ascertained by taking into consideration the description in the detailed description of the invention and the known art as of the filing date is based, is also embodied in the infringing products, etc., whether the function and effect are substantially identical (affirmative in principle)
• The method of determining whether the function and effect are substantially identical where the core of the technical idea was already publicly known as of the filing date of the patented invention or is no different therefrom
Relation to precedent
Follows earlier decisions Stated in the decision
대법원 2014. 7. 24. 선고 2012후1132 판결(공2014하, 1753)
Unofficial English translation
Supreme Court Decision 2012Hu1132 decided July 24, 2014 (Gong 2014 Ha, 1753)
Decisions referred to
[1] 대법원 2009. 6. 25. 선고 2007후3806 판결(공2009하, 1239), 대법원 2010. 5. 27. 선고 2010후296 판결(공2010하, 1296), 대법원 2011. 7. 28. 선고 2010후67 판결(공2011하, 1853), 대법원 2014. 5. 29. 선고 2012후498 판결(공2014하, 1351), 대법원 2014. 7. 24. 선고 2012후1132 판결(공2014하, 1753), 대법원 2015. 5. 14. 선고 2014후2788 판결(공2015상, 821), 대법원 2018. 5. 30. 선고 2016후2119 판결(공2018하, 1200), 대법원 2019. 1. 31. 선고 2017후424 판결(공2019상, 702) / [2] 대법원 2019. 1. 31. 선고 2018다267252 판결(공2019상, 633)
Burden of proof
Not addressed Not in the decision
Open question and revisit condition
How is it decided whether a modification of part of a claimed configuration is of a degree that any person with ordinary knowledge in the technical field could readily have conceived?
The Patent Court's findings on remand, on the remaining grounds of appeal and on whether any special circumstances exist, would show how the three conditions are applied to this spacer. A later Supreme Court decision altering the rule on whether the function and effect are substantially the same as stated in Supreme Court Decision 2018Da267252, or an amendment to Article 97 and Article 135 of the Patent Act, would call for this entry to be read again.
Cross-family AI independent reading & axis check
8 of 8 axes matched GPT-6 Astra (OpenAI, codex CLI) · 2026-10-25
A reader from another model family (GPT-6 Astra), given the official text but not the primary reading, agreed on all 8 axes.
Raw responses and comparison record: Protocol · Blind readings (JSONL) · Axis comparison (JSONL) · SHA-256 (JSON)
Lower-court contrast & scope of application
Lower-court reading vs. Supreme Court holding
Lower-court context: The Patent Court, in its judgment of 19 November 2015 (2015Heo2440), held that the configuration corresponding to element 3 of the claim 1 invention differed from the accused configuration in the number of welded portions and the like, and on that basis held that the subject invention did not produce a function and effect substantially the same as the invention of claim 1. The decision does not record how the court below assessed whether the problem-solving principle was the same.
Supreme Court standard: The Supreme Court held that, reading the specification, including the paragraphs on the problem of the prior art and the effect of the spacer head, together with the state of the art at the filing date, the core of the technical idea on which the patented invention's unique means rests is connecting two spacer bodies with a spacer head that does not easily come off and welding that head to each lower chord under the truss girder to secure sufficient support or embedment against vertical load. Because the accused configuration embodies that same core, the two share the same problem-solving principle, and a difference in the number of welded portions and the like cannot show that the core is not embodied, so the function and effect of element 3 are substantially the same. The court below misapprehended the law on determining the scope of protection of a patent in a way that affected the result, and the whole judgment was reversed and remanded to the Patent Court.
Distinguishing conditions
- A case in which the core of the technical idea, contrasted with the prior art, was already public at the filing date or was no different from it, so that equivalence is decided by comparing the individual functions and roles of the elements concerned.
- A case in which special circumstances are shown, so that the three conditions do not place the subject invention within the scope of rights.
- A case in which every configuration described in the claims is met literally and no changed portion is in issue, since the rule addresses a difference from that configuration.
Record verification notes
Set the accused configuration beside the description of the specification and the registered patent and design publications cited as the state of the art, and state the core of the technical idea that the specification itself claims as unique. Then test each difference the court below relied on, here the shape of the support and the number of welded portions, against that core rather than against the wording of the claim. Confirm as well which grounds of appeal were left undecided on remand, since the Supreme Court omitted them.
From the official text
Points at issue
[1] 확인대상 발명에서 특허발명의 특허청구범위에 기재된 구성 중 변경된 부분이 있는 경우, 확인대상 발명이 특허발명의 특허청구범위에 기재된 구성과 균등한 것으로서 특허발명의 권리범위에 속한다고 볼 수 있는 요건 및 확인대상 발명과 특허발명의 ‘과제 해결원리가 동일’한지 판단하는 방법 [2] 발명의 상세한 설명의 기재와 출원 당시의 공지기술 등을 참작하여 파악되는 특허발명에 특유한 해결수단이 기초하고 있는 기술사상의 핵심이 침해제품 등에서도 구현되어 있는 경우, 작용효과가 실질적으로 동일한지 여부(원칙적 적극) 및 기술사상의 핵심이 특허발명의 출원 당시에 이미 공지되었거나 그와 다름없는 것에 불과한 경우, 작용효과가 실질적으로 동일한지 판단하는 방법
Unofficial English translation
[1] The requirements for the invention to be confirmed, where it has portions of the elements recited in the claims of the patented invention modified, to be regarded as belonging to the scope of the patent right as equivalent to the elements recited in the claims of the patented invention, and the method of determining whether the invention to be confirmed and the patented invention have 'the same principle of solving the problem' [2] Where the core of the technical idea, on which the means for solving the problem unique to the patented invention as ascertained by taking into consideration the description in the detailed description of the invention and the known art as of the filing date is based, is also embodied in the infringing products, etc., whether the function and effect are substantially identical (affirmative in principle), and the method of determining whether the function and effect are substantially identical where the core of the technical idea was already publicly known as of the filing date of the patented invention or is no different therefrom
Summary of the holding
The official text publishes no summary of the holding for this decision. The quotation and factors in this record are copied verbatim from the points at issue; the evidence for each axis is taken from the points at issue, the order and the reasons.
Order
원심판결을 파기하고, 사건을 특허법원에 환송한다.
Unofficial English translation
The judgment of the court below is reversed, and the case is remanded to the Patent Court.
Provisions referred to
[1] 특허법 제97조, 제135조 [2] 특허법 제97조, 제135조
Read 2026-10-25 · Cross-read 2026-10-25. All quotes matched against the official text. The Chinese-character placeholders the court used for anonymised parties are given in their Korean readings, and parenthetical Chinese-character glosses are omitted.
Every entry is published only after all quotes have been matched character by character against the official text, and audited by an independent second reading from a different model family across all eight axes. Both agreed axes and text-grounded interpretive divergences are recorded openly. The ledger is a research record, not an assessment of the court or advice on any matter.
Back to the ledger