All appeals are dismissed.

Costs of appeal shall be borne by each party.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. As to the protection period and starting point of the technical information of this case among the grounds of appeal by the plaintiff and the defendants

A. The purpose of prohibiting infringement of trade secrets is to prevent an infringer from taking undue advantage of his or her superior position than a fair competitor by such infringement, and to enable the person holding the trade secret to return the trade secret to the original location if the infringer had not been such infringement.

The prohibition of infringement of trade secrets shall be carried out within the protection period of trade secrets to achieve this purpose.

The trade secret protection period shall be determined by comprehensively taking into account the substance and difficulty of technical information, whether an infringer or another fair competitor was able to obtain a trade secret in a legitimate way such as independent development or reverse design, the time required to obtain the technical information from the person holding the trade secret, the development speed of relevant technology, the human and physical facilities of the infringer, the freedom of occupation selection of the former employee and the freedom of business activities, etc.

(see, e.g., Supreme Court Order 2018Ma7100, Mar. 14, 2019). Establishment of the scope of the protection period of trade secrets and the starting point to determine the completion period thereof, which is determined through fact-finding as to the protection period of trade secrets, belongs to the exclusive authority of the fact-finding court, unless it is deemed that it is considerably unreasonable in light

B. The lower court recognized the technical information of Article 13 as a detailed circuit design, and calculated the trade secret protection period for the circuit design part of the technical information of Article 13 used up to the latest among the Plaintiff’s technical information of this case (excluding the circuit design of the original register; hereinafter “instant circuit design information”).