What are the Criteria for Patent Infringement? An Explanation of Case Law

The patent system is a system in which the government grants a “patent right” to those who have made inventions that contribute to industrial development. In exchange for disclosing the content of the invention, the inventor is granted the exclusive right to implement the invention.

If a patented invention is implemented without a legitimate right or reason, it constitutes an infringement of the patent right.

In this article, we will explain what specific actions constitute patent infringement, and what actions have been judged as patent infringement in court.

https://monolith.law/corporate/patent-infringement-law[ja]

Three Types of Patent Infringement

Patent infringement is broadly divided into direct and indirect infringement, with direct infringement further divided into literal infringement and equivalent infringement.

• Patent Infringement
• Direct Infringement (Literal Infringement and Equivalent Infringement)
• Indirect Infringement

We will explain each of these three types of patent infringement.

Literal Infringement

The technical scope protected by a patented invention is determined based on the description in the claims (“claims”) attached to the application submitted to the Commissioner of the Japanese Patent Office at the time of patent application. A patented invention is composed as a whole by the constituent elements (elements necessary to identify the invention) described in the claims, so in order for patent infringement to occur, the target product or method must satisfy all of these constituent elements.

If the manner of infringement lacks even a part of the constituent elements of the patented invention, it is considered that patent infringement does not occur.

This is referred to as literal infringement, a type of direct infringement.

However, a patented invention is a technical idea concretized by the description in the claims (Article 2, Paragraph 1 of the Japanese Patent Act), so it is difficult to fully express the technical scope by the description of the text.

Also, if the wording of the claims is interpreted too strictly, it becomes easy to avoid infringing the patent right, which may result in insufficient protection of the patented invention.

Therefore, the technical scope is determined through the interpretation of the text described in the claims.

In interpreting the meaning of the terms described in the claims, the description and drawings attached to the application can be considered. Also, the application history and known technology may be referred to in interpreting the scope of rights.

Equivalent Infringement

It is extremely difficult for a patentee to anticipate all possible forms of infringement and describe them in the claims when applying for a patent.

Also, if the other party can easily avoid the exercise of rights such as injunctions by the patentee by replacing a part of the structure described in the claims with a substance or technology that became apparent after the patent application, it would discourage the general public’s motivation to invent.

This not only contradicts the purpose of the Patent Act, which contributes to the development of industry through the protection and encouragement of inventions, but also goes against social justice and the principle of equity, and could lead to unfair results.

Therefore, there is a legal principle that aims to properly protect patented inventions by interpreting the wording of the claims somewhat expansively, even if the content described as the claims and the content of the technology in question are partially different, as long as they are within the same technical scope.

This is called the doctrine of equivalents.

The doctrine of equivalents does not allow unlimited expansive interpretation of the technical scope.

“Even if there is a difference between the structure described in the claims and the target product suspected of infringement, if the following five requirements are met, the target product is judged to belong to the technical scope of the patented invention as equivalent to the structure described in the claims.” – Supreme Court Judgment, February 24, 1998

This is the doctrine of equivalents, and cases where infringement of rights is recognized by adopting this doctrine are generally called equivalent infringement.

• The different part is not an essential part of the patented invention.
• Even if the different part is replaced with the one in the target product, the purpose of the patented invention can be achieved, and the same effect can be produced.

It is easy for a person skilled in the art to conceive of replacing the different part at the time of manufacturing the target product, etc.

• The target product, etc., is not the same as or easily inferred from the known technology at the time of the patent application for the patented invention.

There are no special circumstances such as the target product, etc., being something that was consciously excluded from the claims during the application procedure for the patented invention.

• If all of these five requirements are met, even if there are parts where the constituent elements do not match, patent infringement may exceptionally occur.

Indirect Infringement

Even if an act does not satisfy all the invention-specific matters described in the claims and therefore cannot be considered direct infringement, for example, the supply of dedicated parts that are only used in products that would infringe the patent right, has a very high potential to induce direct infringement.

If such acts are not regulated at all, the patentee would be unable to do anything even if they are likely to have their patent rights infringed.

The Patent Act provides that certain acts that have a very high likelihood of inducing direct infringement among such preliminary or auxiliary acts of infringement are considered to infringe the patent right or exclusive right to use (Article 101 of the Japanese Patent Act). This is what is called indirect infringement, and it enhances the effectiveness of the protection of patented inventions.

On this point, the Patent Act stipulates:

Article 101 of the Japanese Patent Act (Acts considered to infringe)

The following acts are considered to infringe the patent right or the exclusive right to use.

1. In the case where a patent is granted for an invention of a product, the act of producing, transferring, etc., or offering to transfer, etc., a product that is only used for the production of that product as a business

(2, 3 omitted)

4. In the case where a patent is granted for an invention of a method, the act of producing, transferring, etc., or offering to transfer, etc., a product that is only used for the use of that method as a business

It is stipulated as such.

Although Items 1 and 4 can be said to be essentially the same provision, the term “only” here means that a certain product is only used for the production of a product that directly infringes a patented invention, and that it has “no practical other uses”.

Examples of Patent Infringement

We will look at actual cases of the three types of patent infringement that we have explained.

Residential Map Case

A plaintiff who received the exclusive right to implement a patent named “Residential Map” from the patent holder claimed that the electronic map created by the defendant, Yahoo!, and made available to users on the internet, falls within the technical scope of the patented invention. The plaintiff sought damages from the defendant for this alleged infringement.

In the trial, the court explained the components of the invention from the scope of the patent claim and the description in the specification as follows:

1. In a residential map,
2. General residences and buildings, excluding public facilities and famous buildings that serve as search references, are described only by polygons and addresses, omitting the names of residents and building names,
3. A map with a wide bird’s-eye view is created by compressing the scale,
4. Each page with the map described is appropriately divided and sectioned,
5. An index column is provided as an attachment,
6. All the addresses where the houses and buildings described on the map are located are listed in the index column in correspondence with the page and section numbers where the houses and buildings are described on the map,
7. These are the features of the residential map.

The court judged whether each component constituted a literal infringement. However, for the component “4. Each page with the map described is appropriately divided and sectioned,” the court stated:

Users are looking at the map displayed on the screen, and it cannot be said that they can recognize the section corresponding to the address where the building they are searching for is located among the multiple sections on the page by lines or other methods and symbol numbers. (…) Therefore, it cannot be said that the defendant’s map allows users to recognize the section corresponding to the address where the building they are searching for is located among the multiple sections on the page by lines or other methods and symbol numbers. Thus, it cannot be said that each page of the defendant’s map is “appropriately divided and sectioned.”

Tokyo District Court, January 31, 2019 (2019)

As a result, the court did not recognize a literal infringement and dismissed the plaintiff’s claim. Although the other components were satisfied, component 4 was not.

Ball Spline Case

There was a case where the plaintiff, who owns the patent for an “infinite sliding ball spline bearing,” sought damages for patent infringement against the defendant for manufacturing and selling the product. This is an example of the doctrine of equivalents infringement.

This lawsuit was brought to the Supreme Court, which affirmed the doctrine of equivalents and presented five criteria for its acceptance. The Supreme Court also stated:

Considering these points, the substantial value of a patented invention extends to technology that can be easily conceived as substantially identical to the structure described in the scope of the patent claim by a third party, and it is reasonable to interpret that a third party should anticipate this.

Supreme Court, February 24, 1998 (1998)

The Patent Office’s homepage section on “Patent Examination” states that the doctrine of equivalents is “intended to recognize a broader scope of patent rights.”

Foreign Object Separation and Removal Device Case

The plaintiff, who owns a patent for an invention named “Device for Preventing Co-rotation in a Raw Seaweed Foreign Object Separation and Removal Device,” claimed that the “Raw Algae Foreign Object Removal Washer,” etc. (defendant’s device) manufactured and sold by the defendant, falls within the technical scope of the patented invention. The plaintiff also claimed that the rotating plate and plate board, which are parts of the defendant’s device, fall under the “articles solely for the production” of Article 101, Paragraph 1 of the Japanese Patent Act, and sought an injunction against the manufacture and sale of the defendant’s device and its destruction, as well as damages for tort under Article 100 of the same Act.

The court found that in the patented invention, the rotating plate is an essential component of the “co-rotation prevention device,” and in the defendant’s device, the rotating plate, together with the plate board, is an essential component to prevent clogging of the clearance and the occurrence of co-rotation. The court stated:

In the case of the rotating plate in question, it is not possible to recognize a usage pattern in which only the function not implementing the patented invention is continuously used, and the function implementing the invention is not used at all, as an economic, commercial, or practical usage pattern of the product. Therefore, it is reasonable to recognize that both the rotating plate and the plate board in question are articles used solely for the production of the defendant’s device, which falls within the technical scope of the patented invention 3.

Intellectual Property High Court, June 23, 2011 (2011)

The court ruled that the defendant’s act of manufacturing and selling the rotating plate and plate board constitutes an infringement of the plaintiff’s patent rights.

If a component that forms part of a patented invention is a component used “solely” in a product that constitutes patent infringement, the act of making that component is considered patent infringement.

Summary: Consult Experienced Lawyers to Judge Patent Infringement

Even if it is not a direct infringement, there may be cases where it is exceptionally considered as a patent infringement, such as equal infringement or indirect infringement.

Just because it does not match all the elements of a patented invention, it does not mean that it will never be a patent infringement.

Patent infringement is very difficult to judge, including these matters, so please consult with an experienced lawyer.