In a recent decision, the Korean Supreme Court reaffirmed the claim interpretation principle that the scope of patent protection shall be determined by the description of the patent claim, and cannot be restricted or expanded upon by other disclosures contained in the specification, when it can be determined based solely on the patent claim (Case No. 2021 Da 217011 rendered on June 30, 2021).

▶Background of the Case

Claim 1 of the subject patent (Korean Patent No. 1031432) entitled “Virtual Golf Simulation Apparatus and Method for Compensating a Reduction Rate of a Driving Distance” relates to a virtual golf simulation apparatus for a user to play virtual golf on a hitting mat having a fairway region and a trouble region (rough or bunker). Claim 1 of the subject patent comprises, inter alia, a control unit (“Element 4”) configured to adjust a driving distance according to the trajectory of a golf ball simulated based on a topography of an area where a golf ball is located on a virtual golf course (“topography factor”) and a region on a hitting mat where an actual golf ball detected by a sensing unit is placed (“mat factor”).

The patentee of the subject patent lodged an infringement action against a competitor who also manufactured a virtual golf simulation system (“accused system”). The main issue in dispute between the parties was whether or not the accused system included a feature corresponding to Element 4 of claim 1.

▶The Patent Court Decision

The Patent Court first noted that, from the literal wording of Element 4 alone, the meaning and method of adjustment in the control unit could not be clearly ascertained.

Then, noting that the scope of Element 4 should be objectively and reasonably determined in consideration of the general meaning of claim language and the detailed description of the invention or drawings, the Court ruled that, in light of the technical problem to be solved, the title of the invention, and the entire description of the specification including the drawings, it is reasonable to narrowly interpret the meaning of Element 4 as “adjusting a driving distance by arithmetically calculating a correction value predetermined according to the mat factor with the reduction rate of a driving distance set according to the topography factor.”

Furthermore, the Patent Court pointed out that if Element 4 were broadly interpreted as covering “all cases where the driving distance is adjusted in consideration of both the topography factor and the mat factor,” as asserted by Plaintiff, Element 4 could include what was not supported by the specification of the subject patent or even conventional technologies, which would lead to an unreasonable consequence.

Following the interpretation of Element 4 indicated above, therefore, the Patent Court found that the accused system did not fall within the scope of claim1.

▶The Supreme Court Decision

On appeal, the Supreme Court first reiterated the claim interpretation principle previously enunciated, as follows:

The scope of protection of a patented invention shall be determined by the matters described in the claim (Article 97 of the Korean Patent Act). However, the matters described in the claim . . . should be objectively and reasonably construed by way of examining the technical significance represented by the literal claim wording in consideration of the disclosures of the specification and drawings or the general meaning of the claim wording. However, even in the case of referring to the disclosures of the specification and drawings in claim interpretation, the scope of patent protection cannot be reduced or expanded based on such disclosures in the specification or drawings (see, e.g., Supreme Court Case No. 2011 Hu 3230 rendered on December 27, 2012 and Supreme Court Case Nos. 2019 Da 222782 and 2019 Da 222799 rendered on October 17, 2019).

Applying the claim interpretation principle, the Supreme Court found that:

(1) The technical significance of Element 4 recited in claim 1 of the subject patent lies in simultaneously considering two factors, i.e., the topography factor and the mat factor, in adjusting the driving distance to improve the accuracy of the simulation result.

(2) Claim 1 does not literally specify any concrete method for “adjusting the driving distance in accordance with the topography factor and the mat factor” and the specification of the subject patent does not further define or limit the meaning of “adjusting the driving distance in accordance with the topography factor and the mat factor” with a specific adjustment method. Hence, so long as the topography factor and 3 the mat factor are simultaneously considered in a method for driving distance adjustment, such method may fall within the scope of claim 1.

(3) The accused system is also a virtual golf simulation device, which includes the features of detecting the topography condition near a ball location on a virtual golf course, detecting the mat condition by the sensing device, and adjusting the driving distance in consideration of the two conditions, and the other features that are identical with those recited in claim 1 of the subject patent. Thus, it is reasonable to decide that the accused system, which has the feature of adjusting a driving distance in consideration of both the topography factor and the mat factor, literally infringes claim 1 of the subject patent, since each and every element recited in claim 1 including Element 4 reads on the accused system.

Accordingly, the Supreme Court reversed the Patent Court decision, which had found for non-infringement of claim 1 by limiting the scope of Element 4 to the exemplary embodiments illustrated in the specification.

▶Implication of the Decision

The Supreme Court reaffirmed the well-established claim interpretation principle that the scope of patent protection shall be determined by the wording of the claim in principle, and cannot be restricted or reduced based on other disclosures of the specification or drawings.