In patent infringement cases, the “infringement discussion” (whether or not the alleged infringing product actually infringes the patent right) is the first hurdle in the courts in any country. When it is actually determined to be “infringing”, the discussion shifts to “damage discussion” (how much damage is caused to the patentee by the infringement). Patent doctrine of equivalents discussions in Japan & Comparisons with the United States, Europe and China are truly important.
Please see our previous article on the Doctrine of Equivalents and the differences in its application in Japan as compared to other countries.
Also, please see the JPAA’s 2021 Patent Committee, Five requirements paper for greater background detail.
In infringement discussions, whether or not the accused object is identical to the invention described in the claims (literal infringement) is determined. However, in many cases, there are not perfect copies of patented inventions: ie. where all the elements of the claimed invention have been implemented identically. In many cases, however, some of the elements of the patented invention are modified. In other words, there are overwhelmingly more cases where it is not a literal infringement, but they overlap considerably. In such cases, whether the case should be considered an infringement turns to the question of the “Doctrine of Equivalents”.
The “Doctrine of Equivalents” was long denied by the Japanese courts. Historically, the Doctrine of Equivalents was a patent infringement theory formed in United Kingdom case law in days gone by, and upon which various important verdicts were issued in the US courts. Therefore, it was born in the U.K. and grew up in the U.S. Since 1950, many famous decisions have been issued involving the Doctrine of Equivalents.
In Japan, the Doctrine of Equivalents was first recognized by a Supreme Court decision in 1998. There are no provisions for the Doctrine of Equivalents under the Patent Law in Japan (Articles 70 and 68 of the Japanese Patent Law). Thus, this theory has been recognized by the court in case law.
In the U.S., the doctrine of equivalents has been approved in the courts since the 1950s. It has been discussed and considered in numerous cases since then, various viewpoints have been added and the establishment of the Doctrine has been solidified.
On the other hand, there are still not many cases where the doctrine of equivalents has been tolerated by the Japanese courts. At present, there is no reliable data from the courts, but according to certain information sources, it seems that in about 1 in 10 cases it will be accepted. Then, infringement under the Doctrine of Equivalents in Japan is not as familiar to patent holders as in the United States.
I do speak from experience here. I used the Doctrine of Equivalents in the Osaka District Court in a current infringement lawsuit, but in the end, it was not accepted.
In my opinion, the reason for this somewhat unique Japanese situation – that the Doctrine of Equivalents is rarely accepted – comes from the requirements for its establishment. The requirements for establishing the Doctrine of Equivalents are too strict. I am concerned that legitimate patent holders are not properly protected, and also that the number of infringement lawsuits will remain low. In fact, the total number of patent infringement lawsuits is very low compared to that of the U.S. and China. This point should be considered in comparison with other countries, and I do so below.
Comparison of “establishment requirements of the doctrine of equivalent” in each country.
Below, I cite some of the relevant country-specific patent law, or key related elements of courts’ patent decision-making thinking that apply. I offer little narrative, and as such will be understandable mainly by patent professionals.
- The United States
Basically, in many cases, asserted infringement based on the Doctrine of Equivalents is admitted by the courts. Largely this is due to the presence of the following:
- All element rule
- FWR test (FUNCTION / WAY / RESULT)
- Substitution of elements obviousness/substitutability
- Estoppel
(2) Japan
- The difference is not an essential part*
- Substitutable: the same effect is achieved even if replaced with a difference)
- Easy realization possibility: replacement can be easily conceived at the time of manufacturing counterfeit products
- Easy inference: counterfeit products could be easily inferred at the time of filing
- There is no conscious exclusion: there is no reason for the counterfeit product to be consciously excluded in the application procedure).
* These five requirements were established by the supreme court in 1989. In my opinion, this is very strict in total. Especially for patent holders, in many cases, it has been difficult to persuade Judges of the first requirement: this is the biggest difficulty for patent holders. There are so often clear differences of opinion between patent holders, alleged infringers, and Judges regarding “what is essential” regarding the first requirement.
(3) Europe
German Supreme Court decision
- The means have been changed: Does it have the same objective effect even if it is used?
- Can it be easily conceived that the changing means have the same effect?
- Equivalence of solutions: Can a person skilled in the art evaluate the equivalent even if the means are changed?
* It is said that requirement iii is difficult to clear. As a result, it is similar to the requirements for establishing the Doctrine of Equivalents in Japan.
(4) China
- Identity of function, action, means, and effect: the same as the requirements for establishment in the United States
In China, the Supreme Court admitted the Doctrine of Equivalents in 2015. It is more widely recognized than Japan and even the U.S.
*It is estimated that 50% of the cases claiming the Doctrine of Equivalents are tolerated in China.
Final Comments
As seen above, the reason that the Doctrine of Equivalents is difficult to accept in Japanese infringement lawsuits is the strict associated requirements.
The Doctrine of Equivalents is a theory used in court decisions, not in the provision of the actual law. As a result, whether or not to accept it becomes a question of to what extent the “monopoly by patent rights” is allowed in the economic society of a country.
Even in the U.S, the situation on the Doctrine of Equivalents has changed as between Patent law and Antimonopoly Law, especially, the economic policy of the government.
The low rate of acceptance by the Japanese courts of the Doctrine of Equivalents relates to Japan’s social structure as a non-litigation society.
This matter must be considered from the viewpoint of the socio-economic balance between, on the one hand, the liberal social ideas that respect rights and prioritize the public interest and, on the other, the protection of the public interest where the rights of third parties are restricted by patent rights.
Unfortunately, however, there remain important differences in the protection of patent holders between countries, In my opinion, some sort of international harmonization is needed, for example by WIPO. We must recall that Patent doctrine of equivalents discussions in Japan & Comparisons with the United States, Europe and China are truly important.
