In a recent decision, the Supreme Court invalidated a patent for failure to meet the description requirements, i.e., the enabling disclosure requirement for specification and the clarity requirement for claims (Supreme Court Case No. 2020 Hu 10292 rendered on January 11, 2024).

▶Background of the Case

In the subject patent, titled "Process for Production of Polycrystalline Silicon," claim 1 was directed to a technical feature of controlling a parameter defined by the correlation of multiple process variables within a specific numerical range. However, the specification of the subject patent lacked instructions on how to measure these process variables (e.g., rod volume inside the reactor, temperature of the reactor wall, and volume flow of the reaction gas), essential for determining the numerical range of the parameter.

The main issues regarding the invalidity of the subject patent were, therefore, whether the specification fulfilled the enablement requirement under Article 42(3)(i) of the Korean Patent Act (KPA) ("The specification shall describe the invention clearly and in detail so as to enable a person having ordinary skill in the art to easily practice the invention") and whether the claims met the clarity requirement under Article 42(4)(ii) of the KPA ("The claims shall define the invention clearly and concisely").

Both the Trial Board and the IP High Court concluded that the patent failed to satisfy these description requirements for the specification and claims.

▶Decision of the Supreme Court

The Supreme Court affirmed the lower court decision, ruling that the subject patent violated both the enablement and clarity requirements for the following reasons:

Enablement requirement for the specification:

●The technical feature of the patented invention resides in the optimization of the reaction process by adjusting a parameter defined by the correlation of multiple process variables within a specific numerical range through the control of the interrelated process variables during the reaction. Therefore, the measurements of the process variables during the reaction process were technically crucial for carrying out the patented invention.

●However, the specification fails to disclose the methods for measuring these process variables necessary for determining the numerical range of the parameter. Further, the evidence submitted during the trial failed to demonstrate that a person having ordinary skill in the art, as of the priority date of the subject patent, could easily determine the methods for the measurement of these process variables.

●Therefore, given the technical level at the priority date of the subject patent, it was not feasible for a person of ordinary skill in the art to implement the patented invention, which is defined by the parameter, without resorting to undue experimentation or specialized knowledge. Hence, the specification of the patent is not considered to describe the claimed invention to the extent that a person skilled in the art can readily carry out same.

Clarity requirement for claims:

●The clarity of a claim depends on whether a person of ordinary skill in the art can clearly understand the claimed invention from the disclosures made in the specification, drawings, etc., and the common technical knowledge at the time of filing the application.

●Although the claimed invention includes a parameter composed of process variables such as the volume of the rod, the temperature of the reactor wall, and the volume flow of the reaction gas, the measurement methods of these variables cannot be garnered from the disclosures of the specification. Therefore, the claims of the patent are not considered to clearly describe the inventions.

▶Implications of the Supreme Court Decision

There has been a notable trend in attempting to create new parameters by combining certain variables to secure patents for improved inventions. This strategy may be advantageous for novelty, as such parameters per se are newly introduced.

However, if the variables are measured by using a method/equipment known only to the patentee which is not disclosed in the specification, then a third party would not be able to understand or recreate the invention. The decision, therefore, highlights the necessity of providing clear and detailed descriptions in patent specifications, particularly for parameter inventions. It is essential to delineate the technical significance, measurement methods, conditions, and other relevant details of each process variable constituting the parameter.