Invalid as "Unclear & Non-Enabled"? Korean Supreme Court Reaffirms Standard for Simulation Patents (2024Hu10108)

In a significant decision for innovators in software, simulation, and digital twin technologies, the Korean Supreme Court issued a pro-patent ruling that clarifies the requirements for patent clarity and enablement.

On August 28, 2025, the Supreme Court (Decision 2024Hu10108) reversed a lower court's decision, upholding the validity of a patent for a simulation apparatus that had been invalidated for being "unclear" and "non-enabled."

This ruling provides critical guidance, particularly on the pressing question: Is concrete experimental data required to enable a simulation or software-based invention? The Supreme Court's answer offers powerful support for patentees.

1. Case Background: A Simulator Patent Under Attack

The patent at the heart of this dispute (the "Invention") was for an apparatus—a simulator—designed to verify the normal operation of a controller for a drive unit (specifically, a water hammer facility) without having to run the actual, physical equipment.

The core idea was to:

1. Generate virtual sensor signals (e.g., pressure, water level) instead of using real sensors.
2. Feed these signals as input values (current/voltage) to the controller.
3. Receive the controller's "expected output value" (termed the "adjustment value")—that is, the output the controller thinks the drive unit should produce based on the virtual input.
4. Compare this "adjustment value" (expected output) with the initial "input value" (virtual sensor data) in a feedback loop.

This process allows for verification of the controller's stability and normal operation in a safe, cost-effective virtual environment.

However, a party seeking invalidation (the Defendant) argued that the patent's claims were invalid, violating the Korean Patent Act's description requirements:

• Lack of Clarity (Art. 42(4)(2)): The term "adjustment value (⑤)" was allegedly ambiguous and indefinite.
• Lack of Enablement (Art. 42(3)(1)): The phrase "performs feedback control so that the adjustment value (⑤) is identical to the input value (②)" was argued to be impossible for a person skilled in the art (POSITA) to understand or implement.

The Patent Tribunal agreed with the challenger and invalidated the patent. The Supreme Court, however, emphatically reversed this decision.

2. The Supreme Court's Rulings: Re-Setting the Bar

The Supreme Court's decision clarified the standards for both clarity and enablement, especially as they apply to high-tech inventions.

(1) The Standard for Clarity: "Through the Eyes of a POSITA"

The Court first reaffirmed the familiar standard for clarity:

A claim term is not "unclear" simply because it is abstract or lacks a prior dictionary definition.

The test for clarity is whether a POSITA, after considering the entire specification, drawings, and common technical knowledge at the time of filing, can clearly and unambiguously grasp the technical scope of the invention.

The Court signaled that terms must be read in context. As long as the specification provides a clear context for a POSITA to understand what a term means, even a novel or abstract term, it is not "unclear."

(2) The Standard for Enablement: "Experimental Data Not Always Required"

Most critically, the Supreme Court provided a clear standard for enablement (i.e., the "written description" requirement) for a product (apparatus) invention:

• Enablement is satisfied if a POSITA can produce and use the product.
• The specification must be sufficient for a POSITA to do so without "excessive experimentation" or "special knowledge."
• If a POSITA can sufficiently predict the invention's effect based on the description, the requirement is met—even if the specification lacks concrete experimental data.

This is a crucial clarification. It pushes back against a common invalidation tactic where challengers claim a simulation or software patent is non-enabled simply because it lacks test data from a physical prototype.

3. Applying the Law to the Simulator Patent

The Supreme Court found that the Patent Tribunal had misunderstood these legal principles.

• Was "Adjustment Value" Unclear?No. The Supreme Court held that a POSITA in control engineering would, by reading the specification and diagrams, understand the "adjustment value" to be:

"The current or voltage value corresponding to the expected output signal (④) that the controller (30) predicts the drive unit (40) would generate in response to its control signal (③)."This concept of a predicted or "expected" output is standard in simulation and control systems.

• Was the "Feedback Loop" Non-Enabled?No. The Court interpreted this phrase not as a physical impossibility, but as describing the verification logic of the simulator itself. A POSITA would understand this to mean:

"The simulator inputs a value (②), receives the controller's expected output (the 'adjustment value' ⑤), and compares the two to check for identity. This comparison loop verifies the controller's normal operation and stability."This is a standard verification routine in simulation environments.

Conclusion: The Supreme Court concluded that the patent was both clear and enabled. The specification provided a concrete structure (computer, simulator, controller) and described its operation in a way that a POSITA could build and use the simulator and predict its effect (verifying controller stability).

4. Practical Implications: What This Means for Your IP Strategy

This decision is a strong, favorable signal for high-tech patents. At Pine IP Firm, we see the following key takeaways.

1) For Patent Owners and Applicants (Defense)

• Focus on Context, Not Definitions: When drafting claims with novel or abstract terms ("virtual signal," "expected value"), the key is to ensure the specification (especially flowcharts, block diagrams, and operational descriptions) provides a clear context for a POSITA to understand them.
• Don't Fear a Lack of Physical Data (for Simulations): This case is a powerful shield. For simulation, digital twin, or AI inventions, you do not necessarily need data from a physical-world test. Instead, invest in a detailed description of the logic, the algorithm, the data flow, and the component interactions. This is what provides enablement.
• Use Block Diagrams and Flowcharts: For control and software patents, diagrams are not optional. They are the most effective way to make abstract concepts (like the signal flow in this case) concrete, satisfying both clarity and enablement requirements.

2) For Competitors and Challengers (Attack)

• "It's Vague" Is Not Enough: Simply arguing that a term is "unfamiliar" or "abstract" will likely fail. An invalidity challenge must now technically prove why even a POSITA, reading the entire specification, would be unable to understand or implement the invention.
• "No Experimental Data" Is a Weak Argument: This decision significantly weakens invalidity attacks based solely on a lack of experimental data. A challenger must now show why the lack of data renders the invention non-enabled—for example, by proving that the logic is fatally flawed or that "excessive experimentation" (not just any experimentation) would be required to implement it.

Conclusion: A Favorable Wind for Software & Simulation Patents

The Supreme Court's 2024Hu10108 decision reinforces a practical, pro-innovation approach to patent law. It recognizes that for cutting-edge fields like digital twins, virtual commissioning, and AI-driven control systems, abstract concepts are a necessary part of the invention.

The court has made it clear: as long as the patent specification provides a sufficient blueprint for a skilled person to understand and build the invention, it should not be easily invalidated on "clarity" or "enablement" grounds.