The Korean Supreme Court recently held that a divisional application was eligible for the 12 month grace period for self-disclosure based on the filing date of the parent application even if the grace period was not claimed at the time of filing the parent application (Supreme Court 2020Hu11479 rendered on August 31, 2022).

When determining novelty/inventiveness, self-disclosure can serve as a prior art reference, but the Korean Patent Act ("KPA") allows for a grace period for self-disclosure within 12 months of filing a patent application. The grace period is not automatically applied. Instead, the applicant should request the grace period at the time of filing and submit supporting documents within 30 days from the filing date.

In 2015, the KPA was amended to expand the period for claiming the grace period. More specifically, applicants could request the grace period even after the filing date under certain circumstances. For a divisional application, however, the Patent Court had held that the applicant cannot claim the grace period if the applicant did not request it in the parent application. The Supreme Court 2020Hu11479 Decision overruled this Patent Court's decision.

In the 2020Hu11479 case, Plaintiff filed a parent application on December 23, 2014, within 12 months after Plaintiff's self-disclosure that is identical to the invention of the parent application. When filing the parent application, Plaintiff did not claim a grace period for self-disclosure. Subsequently, Plaintiff filed a divisional application on August 30, 2016 and claimed the grace period for self-disclosure based on the filing date of the parent application. The Supreme Court held that if a divisional application is properly filed, it is deemed to have been filed on the filing date of the parent application according to Article 52(2) of the KPA. Thus, according to the Supreme Court, as long as the procedural requirements for a grace period for self-disclosure are satisfied, the grace period for self-disclosure should be recognized for the divisional application based on the filing date of the parent application, even when the grace period was not claimed at the filing of the parent application. Further, the Supreme Court explained that there exists a practical need to recognize the grace period for divisional applications because there may be a situation where the claims of a divisional application relate to the applicant's self-disclosure, while the claims of a parent application do not. Accordingly, the Supreme Court ruled that Plaintiff's self-disclosure will not be considered as prior art for novelty or inventiveness during the prosecution of the divisional application.

In brief, the Supreme Court decision clarified the requirements for claiming the grace period by holding that the grace period for self-disclosure with respect to the divisional application can be claimed based on the filing date of the parent application even when the grace period was not claimed in the parent application. In order to enjoy the grace period for self-disclosure, Applicant may (i) claim the grace period at the time of filing an application pursuant to Article 30(2) of the KPA, (ii) claim the grace period within the period during which the application can be amended pursuant to Article 30(3) of the KPA, or (iii) claim the grace period for a divisional application pursuant to Article 52(1) of the KPA, even when the grace period was not sought in the parent application.