1. Case Overview
Defendant holds a patent related to a ventilation device for air respirator masks. Plaintiff (a competitor) filed an invalidity trial, arguing that the defendant's patent lacked an inventive step. On December 7, 2023, the Korean Intellectual Property Tribunal (KIPT) dismissed the invalidity claim. The plaintiff then filed a lawsuit to cancel the KIPT decision in the Patent Court, presenting a modeling result based on prior art to support its inventive step challenge.

2. Key Legal Issue
Can a patent be deemed obvious based on a modeling result derived from prior art, rather than the prior art itself?

3. Our Defense
We demonstrated that the plaintiff's modeling was not a direct reproduction of the prior art. Even if the prior art could theoretically lead to the plaintiff's modeled result, this would represent only one among many possibilities, not an obvious extension of prior art. We successfully proved that a person of ordinary skill in the field would not have easily arrived at the patented invention based on the prior art.

4. Court's Decision
On January 23, 2025, accepting our arguments, the Patent Court upheld the validity of the defendant's patent and dismissed the plaintiff's claims (Patent Court Decision No. 2024Heo10634, dated January 23, 2025).

5. Significance of the Decision
This decision clarifies that a prior art-based model cannot serve as direct evidence of lack of inventive step unless the modeled result is explicitly disclosed in the prior art. This decision sets an important precedent for future patent disputes allegedly based on modeling techniques used to challenge inventive step.