Open Decision Ledger · IP, data & telecommunications
Claim clarity and the description requirement for a product invention
Supreme Court, Aug. 28, 2025, 2024Hu10108 (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: 등록무효(특)
Official text on the National Law Information Center
Question
Where a patent claim uses a term that expresses the invention obscurely, may it be registered, and when does a product invention meet the description requirements of Article 42(3)(i) of the Patent Act?
Holding
No, in principle. Article 42(4)(ii) of the Patent Act requires the claims to be clear and concise, and Article 97 makes the scope of protection follow what is written in the claims, so an obscure expression of the invention's composition is not allowed; whether the invention is clearly described is decided case by case, by asking whether a person skilled in the art can clearly grasp the invention from the claim items, in view of the description, drawings and the common general knowledge at the filing date. For a product invention, working the invention means producing or using the article, and the requirement of Article 42(3)(i) is met where a skilled person, without undue experiment or special knowledge, can produce and use the article from what is written in the description and can sufficiently predict the effect even without experimental proof. The disputed simulator claim met both requirements, because the adjustment value term and the feedback control could be understood in that way.
Points at issue, verbatim
특허출원 시 청구항에 발명의 구성을 불명료하게 표현하는 용어를 기재할 수 있는지 여부(원칙적 소극) 및 발명이 명확하게 적혀 있는지 판단하는 방법
Unofficial English translation
Whether, upon filing a patent application, a term that ambiguously expresses the components of the invention may be recited in the claims (in principle, negative) and the method of determining whether the invention is clearly described
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
구체적인 실험 등으로 증명이 되어 있지 않더라도 특허출원 당시의 기술수준으로 보아 통상의 기술자가 발명 효과의 발생을 충분히 예측할 수 있다면, 위 조항에서 정한 기재요건을 충족한다고 볼 수 있다
Unofficial English translation
Even if it has not been proved by specific experiments or the like, if a person of ordinary skill in the art can sufficiently predict the occurrence of the effects of the invention in light of the level of technology at the time of filing the patent application, the description requirements prescribed in that paragraph may be regarded as satisfied
Factors
- 특허출원 시 청구항에 발명의 구성을 불명료하게 표현하는 용어를 기재할 수 있는지 여부(원칙적 소극)
- 발명이 명확하게 적혀 있는지 판단하는 방법
- 특허법 제42조 제3항 제1호의 규정 취지
- ‘물건의 발명’에서 발명 ‘실시’의 의미
- 위 조항에서 정한 기재요건을 충족하는 경우
Unofficial English translation
• Whether, upon filing a patent application, a term that ambiguously expresses the components of the invention may be recited in the claims (in principle, negative)
• The method of determining whether the invention is clearly described
• The purpose of Article 42 (3) subparagraph 1 of the Patent Act
• The meaning of "working" of an invention in an "invention of a product"
• Cases where the description requirements prescribed in that paragraph are satisfied
Relation to precedent
Follows earlier decisions Stated in the decision
대법원 2006. 11. 24. 선고 2003후2072 판결(공2007상, 72)
Unofficial English translation
Supreme Court Decision 2003Hu2072 decided November 24, 2006 (Gong 2007 Sang, 72)
Decisions referred to
[1] 대법원 2006. 11. 24. 선고 2003후2072 판결(공2007상, 72), 대법원 2014. 7. 24. 선고 2012후1613 판결, 대법원 2022. 1. 27. 선고 2019다277751 판결 / [2] 대법원 2011. 10. 13. 선고 2010후2582 판결(공2011하, 2381), 대법원 2016. 5. 26. 선고 2014후2061 판결(공2016하, 893), 대법원 2018. 10. 25. 선고 2016후601 판결, 대법원 2021. 12. 30. 선고 2017후1298 판결(공2022상, 273)
Burden of proof
Not addressed Not in the decision
Open question and revisit condition
How far may the description cure an obscure term in a claim, when the scope of protection is fixed by what is written in the claim items under Article 97?
The Patent Court's judgment on remand, applying this standard to the same simulator claims and to the other grounds of appeal, would require this entry to be read again. So would an amendment to Article 42(3)(i), Article 42(4)(ii) or Article 97 of the Patent Act, or a later Supreme Court decision changing the clarity or enablement test.
Cross-family AI independent reading & axis check
7 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 7 of the 8 axes; the readings differed on axis 8 (open question and revisit condition).
Axis 8 (Open question and revisit condition): Primary “How far may the description cure an obscure term in a claim, when the scope of protection is fixed by what is written in the claim items under Article 97?” vs Independent “How should the remaining grounds of appeal, which the Court did not address, be resolved?”
The primary asks how far the description can cure an obscure claim term given that scope is fixed by the claims, while the independent asks how the remaining grounds of appeal should be resolved, which is a different unresolved point.
특허출원 시 청구항에 발명의 구성을 불명료하게 표현하는 용어를 기재할 수 있는지 여부(원칙적 소극) 및 발명이 명확하게 적혀 있는지 판단하는 방법Raw 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 20 December 2023 (2023Heo11050), held that claim 1 contained an obscure statement in its claim items, so that a person skilled in the art could not clearly grasp the invention, and that the description of the invention was not written clearly and in detail enough for a skilled person to work it easily. It therefore held that claims 1, 2 and 3 all failed the requirements of Article 42(4)(ii) and Article 42(3)(i) of the Patent Act, and that the registration had to be invalid.
Supreme Court standard: The Supreme Court held that the Patent Court had misapprehended the legal principle on the description requirements and had failed to hold the necessary examination, which affected the judgment. Reading the technical problem, the means of solving it and the description together, it found that a skilled person could clearly grasp the simulator invention from the claim items, that the adjustment value means the current and voltage values corresponding to the output signal the drive unit is expected to produce when the controller sends the control signal, and that feedback control to make that value equal to the input value could be understood. The Court therefore reversed the judgment and remanded the case to the Patent Court, with the unanimous agreement of the participating Justices, leaving the other grounds of appeal unexamined.
Distinguishing conditions
- A claim term that remains obscure even when the description, drawings and the common general knowledge at the filing date are taken into account.
- A case in which a skilled person cannot produce and use the article from what is written in the description without undue experiment or special knowledge.
- A case in which the occurrence of the invention's effect cannot be sufficiently predicted at the technical level of the filing date, so that the effect rests on unproven expectations.
Record verification notes
Set each disputed claim term against the description and drawings as a whole, since the Court read the adjustment value and the feedback control from the description and the stated technical problem rather than from the claim alone. Then test enablement separately: whether the article can be produced and used without undue experiment, and whether the effect can be predicted without experimental proof. Note also that the Court decided only claim 1 expressly and left the other grounds of appeal undecided, so a different ground of invalidity is untouched by this entry.
From the official text
Points at issue
[1] 특허출원 시 청구항에 발명의 구성을 불명료하게 표현하는 용어를 기재할 수 있는지 여부(원칙적 소극) 및 발명이 명확하게 적혀 있는지 판단하는 방법 [2] 특허법 제42조 제3항 제1호의 규정 취지 / ‘물건의 발명’에서 발명 ‘실시’의 의미 및 위 조항에서 정한 기재요건을 충족하는 경우
Unofficial English translation
[1] Whether, upon filing a patent application, a term that ambiguously expresses the components of the invention may be recited in the claims (in principle, negative) and the method of determining whether the invention is clearly described [2] The purpose of Article 42 (3) subparagraph 1 of the Patent Act / the meaning of "working" of an invention in an "invention of a product" and cases where the description requirements prescribed in that paragraph are satisfied
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 제42조 제4항 제2호, 제97조 [2] 특허법 제42조 제3항 제1호
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.
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