Reiterating that patent infringement should be determined by reviewing solely whether the accused product has all elements recited in a patent claim, either literally or under the doctrine of equivalents, the Korean Supreme Court overturned the Patent Court’s decision, rendered under the improper rationale that absence of the defendant’s intent for having certain claim elements in the defendant's product for the purpose of achieving certain effect (that is recited in the patent claim) constituted an exculpatory or exonerating factor (Case No. 2017 Da 227516 rendered on January 30, 2020).

▶Background of the Case  

The patent-in-suit related to an LED lighting apparatus.  Specifically, claim 1 was directed to an air-cooling type LED light apparatus comprised of (i) a main body having an internal space, an inverter-holding part, a base extending from the inverter-holding part and a plurality of air-outlets communicating with the interior space; (ii) an LED module facing a lower surface of the base and equipped with LED lights; (iii) an inverter located in the inverter-holding part and connected to the LED lights so as to supply electric power to the LED lights; (iv) a diffusion cover combined with the main body and housing the LED module; and (v) a holding cover combined with the main body and housing the inverter, (vi) wherein internal air inside the diffusion cover flows into the internal space of the main body and emits through the air-outlets, and (vii) external air flows into the inside of the diffusion cover through a gap between the diffusion cover and the base, so as to cool the LED module.

The patentee filed an infringement action based on the subject patent against a competitor.  The district court ruled against the patentee, finding that the defendant's product did not fall within the scope of the subject patent.  The patentee filed an appeal before the Patent Court. 

▶Patent Court Decision 

On appeal, there was no dispute between the parties that the defendant's product contained elements (i) to (v) recited in claim 1 of the subject patent. 

As to elements (vi) and (vii), however, the Patent Court interpreted that these elements were meant to be provided for the specific purpose of cooling the LED module.  In this respect, the Court found that, in the accused product, the LED module was bent slightly downwards due to its weight, so as to naturally form a tiny space between the LED module and the base; and the diffusion cover was attached to the base by inserting the hooks of the diffusion cover to holes in the base, resulting in a small gap between the attached diffusion cover and the base.  Based on the above analysis, the Patent Court determined that the tiny space and the small gap did not correspond to elements (vi) and (vii) of the subject patent since they were not provided by design or intentionally for the specific purpose of cooling the LED module, but were formed as a result of the assembly of the LED product. 

Accordingly, the Patent Court affirmed the district court’s decision based on the determination that the defendant's product lacked elements (vi) and (vii).  The patentee appealed to the Supreme Court. 

▶Supreme Court Decision

The Supreme Court recognized that the accused product had a tiny space between the LED module and the base, air-outlets in the main body, and a small gap between the diffusion cover and the base; external air flowed into the inside of the diffusion cover through the small gap, while internal air inside of the diffusion cover flowed out through the tiny space and the air-outlets, thereby cooling the LED module. 

However, the Highest Court admonished that the Patent Court misconstrued the standard for determining patent infringement, by improperly taking into consideration lack of the defendant's purposeful intent in forming the tiny space and the small gap in the defendant’s product. 

Accordingly, the Supreme Court overturned the Patent Court decision and remanded the case to the lower court. 

▶Implication of the Decision

The Supreme Court reconfirmed the well established edict that a claim shall be held infringed if each and every element recited in the claim reads on the accused product or process.  This decision further elucidated that if an effect or result produced by an element is recited in a claim, patent infringement should be decided by examining whether the effect or result is actually produced by the element regardless of whether such element has been provided intentionally so as to attain the specific effect.