New Supreme Court Decision on Doctrine of Equivalents in Korea

The rationales of the doctrine of equivalents in Korea are basically similar to those of the U.S. Namely, when an accused product or process performs substantially the same function in substantially the same way to obtain the substantially same result of the patented invention, the accused product or process infringes the patent right.

In particular, the Korean Supreme Court held that the accused product or process infringes a patent where an element of the patented invention is substituted with another element and, if (i) the technical concepts or principle to solve the objective of the patented invention and the accused invention are the same or common; (ii) the substituted element in the accused invention performs substantially the same function in substantially the same way to obtain the substantially same result of the patented invention; (iii) such substitution is obvious to an ordinarily skilled person in the art. However, the doctrine of equivalents shall not be applicable to the circumstances that (iv) the accused substitution was already known to skilled persons in the art at the time of filing an application and (v) the accused element was excluded from the claimed invention during prosecution.

On July 24, 2014, the Supreme Court further clarified the scope and meaning of the above (1) requirement of DOE; the technical concepts or principle to solve the objective of the patented invention and the accused invention must be the same or common.

The patent claimed a cutter for dry seaweed. The seaweed cutter has cutting blades laid out in a grid pattern. Seaweed is placed on top of the cutting blades and pressed from top to down and then sliding down into a container through a grid-patterned box attached to the bottom of the cutting blades. The patented invention can achieve a cutting and storing of seaweed in a single process.

The accused cutter is different from the patented cutter in which the accused cutter has moving blades that move from top to down and cut seaweed. Instead, the patented invention does not have moving blades. Except the position of blades, other technical features of the two devices are the same. Two cutters perform the same function in the substantially same way and achieve the same result.

However, the Seoul High Court denied patent infringement under DOE because the accused cutter did not meet the (1) requirement of DOE. The accused cutter cut seaweed in a different way from the patent technology; there is no the same technical principle of resolving the technical problem.

The Supreme Court vacated the lower court decision. The Court held that the "essence or core of the technical idea" must be determined between two cutters in order to apply DOE and then found that two cutters used the same technical idea because it should be the incline of the grid patterned box that allowed seaweed to be automatically stored after being cut and it is found in two cutters although two cutters employed different embodiments. The Court found that the change to position of the cutting blades was obvious. The Supreme Court decision clarified (1) requirements of DOE under the Korean patent law. In practice, patentees may have higher chance to apply DOE under the recent decision.

Joint Ownership of Patents in South Korea

Under the Korean patent law, when there are joint inventors of a single invention, each inventor is entitled to be a joint owner in the right to obtain a patent of the invention. Without any agreement to assign his right, the joint owners must file an application for a patent together. Otherwise, the application shall be rejected or the granted patent shall be invalid. In the absence of an agreement to the contrary, each joint owner has an equal partial interest in the invention as a whole. When a company is an employer of an employee inventor and the employee is a co-inventor, the company shall be a joint owner of the invention through assignment.

The Korean patent law provides that joint patent owners may freely make, use and practice the patented invention without consent to the other joint owners. In this regard, each co-owner does not have the duty to account profits to the others.

However, each co-owner may not assign the partial right of the patent to a 3rd party without consent of the other co-owners. Namely a joint owner may sell his own interest in the paten only when the other joint owners consent such an assignment.

Furthermore, a joint owner may not license the patented technology to a third party based on his co-ownership of the patented invention unless he has obtained consent of the other joint owners about the license.

The Korean Patent Act has specific provisions for such restrictions of joint ownership. This principle of the Korean patent law is to protect each co-owner from an unreasonable change of co-ownership. If a joint owner may freely assign or license the jointly owned patent, other co-owners may be at the mercy of the co-owner. For example, in case a co-owner assigned his co-ownership to a large company and the other co-owner is a very small company and then a new co-owner large company may use and practice the patented technology as a whole independently without any duty of account profits to the other co-owners, the new joint may have the whole value of the patent and the small company does not have any profit.

However, joint owners may vary their rights by contract. The statutory default rule under the Korean patent law controls unless there is an agreement to the contrary.

Requirements and Procedures when a foreign applicant claims 12-months Grace Period in Korea

Based on 12 months grace period under the Korean patent law, an inventor or his assignee may obtain a patent through filing an application for any already disclosed invention within 12 months from the date of novelty destroying event. The disclosure of an invention as novelty destroying event might be done by an inventor, his assignee or a 3rd party. In order obtain such benefit of grace period under the Korean patent law, a foreign applicant must meet substantive and procedural requirements as follows:

1. Priority claim under the Paris Convention or PCT may not apply beyond 12 months from the first disclosure.


For example, an inventor disclosed his invention on October 1, 2013 and filed a patent application with claiming benefit of grace period on December 1, 2013 at USPTO. Later, the applicant filed a Korean patent application based on the US patent application with priority claim under the Paris Convention on December 1, 2014. The applicant may not obtain a patent in Korea because the disclosure of the invention on October 1, 2013 shall destroy the novelty of the invention filed at KIPO. Because an applicant did not file the application within 12 months from the first event of invention disclosure, he may not claim benefit of 12 months grace period. Accordingly the priority claim under the Paris Convention cannot save the lost of novelty.

Therefore, a foreign applicant must file a Korean patent application at KIPO with 12 months from the first disclosure event regardless of claiming priority under the Paris Convention or PCT. Otherwise, a foreign applicant will lose an chance to obtain a patent in Korea under 12 months grace period.

2. An applicant must disclose all and each event of invention disclosures when files a patent application at KIPO


When an inventor had disclosed his invention several times before he has filed a patent application before KIPO, the applicant must disclose all of them and request benefits of 12 months grace period for all and each events of invention disclosures. Otherwise, the unreported event may be a basis to deny the novelty of the filed invention.

For example, (1) an inventor disclosed an abstract about his invention in a brochure of a conference on October 1, 2013 and (2) gave a detailed presentation about his invention before audience in the conference on October 10, 2013 and then (3) published his article about the invention on November 1, 2013 and further (4) the organizer of the conference uploaded the inventor's presentation at an official website of the conference on November 10, 2013.

In order to be safe based on benefits of grace period under the Korean patent law, an inventor must disclose all of the above 4 events and claims benefits of 12 months grace period for all of them when he files a patent application at KIPO within October 1, 2014. For example, if an applicant did not report No. 4 event of posting his presentation at the conference website, it may be a basis for denying novelty of the invention. However, in my view, it may be possible to argue that the inventor could not know the event and did not have any intent to deceive KIPO. Accordingly an applicant may probably overcome such a hurdle but it is better to check all possible events of disclosures and report all and each of them to KIPO. On the other hand, in case an applicant did not disclose No. 2 event or No. 3 event, he cannot save his application from loss of novelty by his disclosing the invention before the filing date.

Steady Increase of Patent Applications to KIPO from Foreign Applicants

The number of patent applications in Korea has steadily increased in 5 recent years. According to statistics from KIPO, the number of patent applications in 2013 was 204,589 that was 8.6% increase compared to that of 2012. 44,894 new patent applications among them were filed by foreign applicants. It has increased by 11.7% compared with the numbers during the same period in 2012. We could observe the steady increases in the numbers of patent applications from foreign applicants by in recent 5 years that ranges from 5.8% to 11.7%.

Considering the background of such steady increases, we could observe that many Korean companies became key players in the world's major manufacturers and sellers of smartphones, semiconductors, display panels, TVs, etc. Accordingly manufacturers of parts and raw materials have critical interests in Korean market, too. Naturally they need IP protection about their businesses in Korea and have filed more patent applications in Korea.

Amendments to the Korean Patent Act from January 1, 2015

1. An applicant may file an English specification without the Korean translation


An applicant may file a provisional application in English without the Korean translation in order to obtain a patent filing number and date in Korea. The description of an invention in English does not have to be a formal patent specification. A simple literature about an invention should be sufficient if it describe all elements of an invention clearly. Under the current law, an applicant may file a provisional application in Korean without claims. Furthermore, an applicant may file a formal application in English without the Korean translation in order to obtain a patent filing number and date in Korea. Within 14 months from the earliest priority date, an applicant must file the Korean translation and claims.

2. 32 months deadline for submitting the Korean translation for national entry of PCT application


Under the current Korean law, a PCT applicant must enter a Korean national phase of a PCT application through filing documents for entering a Korean national phase of a PCT application that includes the Korean translation of a PCT specification. However, under the new law, a PCT applicant may request a one-month extension of time for submitting the Korean translation and thus may submit the Korean translation within 32 months from the earliest priority date. But, an applicant may not extend the 31 months deadline for national entry of a PCT application in Korea.

3. An applicant may correct Korean translation errors based on an original foreign language specification


Under the current Korean law, any amendment beyond the scope of the Korean translation filed shall be regarded as new matter even though the amendment has been based in the original specification in foreign language. Accordingly it is critical once there is any translational error in the Korean translation. The revised new law allows that an applicant may correct any translational errors based on the original foreign language specification and the PCT specification in foreign language.