Patent Court 2023Na11276: Enhanced Damages for Willful Patent Infringement
Pine IP Firm
April 29, 2025
The Patent Act amendment effective July 9, 2019 allowed enhanced damages of up to three times the proven amount for willful patent infringement. Patent Court Case No. 2023Na11276, decided October 31, 2024, addresses willfulness, application of the amendment to continuing infringement, and calculation of the multiplier.
A kitchenware manufacturer sued a competitor for manufacturing and selling vacuum-pot products that used a patented cooking-vessel lid without authorization.
The court's factual findings included the following:
The Patent Court found willful infringement based on the defendant's prior knowledge, failed licensing discussions, continued conduct after the cease-and-desist demand, and sales after the related proceedings had concluded.
An expert opinion on patent invalidity and a change in management did not negate intent. The opinion was prepared after infringement began, stated that it had no binding legal effect, and was inconsistent with the outcome of the related proceedings.
The defendant argued that enhanced damages were unavailable because the infringement began before the amendment took effect. Article 3 of the supplementary provisions stated that the amended rules would apply from the first infringing act occurring after enforcement.
The court interpreted that provision as defining the period of recoverable enhanced damages. Infringing acts committed after July 9, 2019 were subject to the amended rule even though the course of infringement began earlier. The multiplier was therefore limited to damages arising from post-effective-date acts.
The court calculated damages under Article 128(4) of the Patent Act using the infringer's profits. It applied a 7.6% deemed profit margin to approximately KRW 50.1 billion in sales and then applied a 20% contribution rate for the patented invention. The resulting basic damages were approximately KRW 760 million.
The 20% contribution rate reflected the patented lid's contribution to sealing performance and visual differentiation. The court also considered other patented or designed features, including the check valve, packing structure, and standing handle, together with nontechnical contributions such as capital and marketing.
The court applied a twofold multiplier to approximately KRW 88 million in damages arising from infringement between July 9, 2019 and October 31, 2022.
The multiplier reflected the factors listed in Article 128(9), including the parties' relative positions, the degree of intent, the duration and number of infringing acts, economic benefit, financial condition, and the defendant's limited remedial efforts.
The final award was KRW 850,664,056 plus delay interest. The amount combined the damages calculated for the period before the amendment with twice the damages calculated for the post-amendment period.
