[Patent Infringement Litigation in Korea - 3] Check Points & Actions Must Be Considered Before Enforcement Actions

Patented claims must be valid and infringed in theory. However such claims are not common in reality. Accordingly a patentee must check strength of his patent before enforcing his patent against accused infringers. To be a valid patent claim, it should be strong enough to sustain invalidity challenges. The scope of the claim must be narrow enough to be novel and non-obvious over the prior art. On the other hand, a claim should be infringed by the competitor’s product or process. For this purpose, the scope of a claim must be broad enough to cover competitor’s product or process. These are contradictory and it is really hard to achieve desirable balance between two opposites.

 

Before filing a patent infringement lawsuit, it is desirable for a patentee to check strength of each patented claim based on thorough prior art search. Usually, it is necessary to fix any errors in issued patents, protect claims from possible invalidity challenges through amending claims to be novel and non-obvious over the prior art; and further pursue claims directed to competitor’s products or process if possible.

 

Two ways are available to amend patented claims after granting a patent in Korea. Before a patent infringement action, a patentee may amend claims as precautionary measure through ex parte proceeding at the IPT of KIPO. Namely, the first way is an independent petition to request amendment as like re-issue request in the U.S. Actually, Korea use a different terminology of “correct” for granted patents rather than “amend” for pending application before grant. It is to differentiate from each other because two terms do not have the same meaning.

The second option to amend a patented claim is correlated with an invalidity proceeding. During invalidity proceeding, a patentee may request to amend granted claims as a defense. It is very common to file a motion to correct patents during invalidity proceeding. This is inter partes proceedings between a patentee and a challenger and consolidated in invalidity proceeding. Both parties may argue whether or not such amendment to be allowed.

 

A patentee may amend granted claims of a patent within the scope of original disclosure and within the scope of protection of the patent as granted. In reality, post grant corrections of claims are allowed within a very limited scope. The correction must be made to (1) narrow a claim, (2) correct typological errors, or (3) clarify ambiguous description. The correction must not broaden or alter the scope of the patent right.

[Patent Infringement Litigation in Korea - 2] Claim Interpretation under Korean Patent Law

1. All Elements Rule

The scope of a patent is defined by the elements of a claim. It is well settled that each element in a claim is deemed material to defining the scope of the patented invention. Therefore, only when every element defined in a claim is found in an accused product or process, the accused product or process literally infringes the patent right.

2. Doctrine of Equivalents

 

It has been long time for the Patent Court and the Supreme Court to adopt the doctrine of equivalents as a part of Korean patent law for interpreting claims.

 

The rationales of the doctrine of equivalents in Korea are similar to those of the U.S. Thus, it is true that if the 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 infringes the patent in Korea.

 

In particular, the 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.

 3. Prosecution History Estoppel

Based on the doctrine of equivalents, a patentee cannot regain his rights to any elements that were abandoned through an amendment or a response during prosecution. For example, when an element is excluded through an amendment in order to secure novelty and non-obviousness in response to the examiner’s rejection, an invention with an equivalent element is outside the scope of the patent.

The Supreme Court held that prosecution history estoppel should be applied in view of specification, opinions of an examiner from filing of the application to issuance of a patent and the intent of an applicant as indicated in the amendments and arguments during prosecution. Furthermore, in a patent containing more than one claim, the prosecution history of each claim should be independently reviewed to decide whether certain subject matter was intentionally excluded from the scope of the claim.

 

[Patent Infringement Litigation in Korea - 1] Cease and Desist Letter – Warning Letter

When a patentee finds his patent right being infringed by a third party, he may send an alleged infringer a cease and desist letter. It is to warn the infringer of legal responsibilities and demand the cessation of infringement activities. Furthermore, the accused infringer, at least from the day of receiving the warning letter, will not be able to deny his intent or negligence in the infringement activities.

 

This warning letter plays an important role in proving the claim of damage compensation as well as the criminal liability for infringement. For criminal action, it is required to prove the intent of an infringer regarding infringing acts of a patent without doubt. In particularly, infringer’s intent in the infringement shall not be presumed even if a patent marking is present on the patented product. With a warning letter, it is easy and convenient to prove the infringer’s intent beyond reasonable doubt. Therefore, a patentee has often sent warning letters to infringers to point out the ownership of the patent and their infringing activities.

The Doctrine of Equivalents (DOE) 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.

Practical Points Under Korean Patent law on Joint Ownership of Patent in 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. Or anyone may obtain the joint ownership through buying a portion of a patent ownership.

The joint owners of an invention before a registered patent 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 owners of a patent 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 his right of the patent in part 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, under Korean patent law, 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.

For example, in case 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 determine and vary their rights by contract. The statutory default rule under the Korean patent law controls unless there is an agreement to the contrary.