【PATENT★】”LEARNING IMPLEMENT” Appeal Case: A case in which the Court found that the plaintiff’s (appellant’s) product merely produces an additional effect in addition to producing the effect of the patented invention, and acknowledged the existence of the second requirement of the doctrine of equivalents.

Even if, within the structure stated in the scope of the claims, there is a part that is different from a product manufactured or a process used by the other party (the “subject product”), it is reasonable to understand that the subject product falls under the technical scope of the patented invention as an equivalent to the structure stated in the scope of the claims if the following requirements are fulfilled:

(i) said part is not the essential part of the patented invention [Non-essential Part];

(ii) even if said part is replaced with a part in the subject product, the purpose of the patented invention can be achieved, and the same function and effect can be obtained [Interchangeability];

(iii) a person ordinarily skilled in the art could have easily conceived of such replacement at the time of the manufacturing of the subject product [Conceivability of Interchange];

(iv) the subject product etc. is neither identical with art publicly known at the time of the filing of the patent application for the patented invention nor one that a person ordinarily skilled in the art could have easily conceived of at the time of said filing based on such publicly known art [Non-obviousness]; and

(v) there are no special circumstances such as the fact that the subject product falls under inventions that were intentionally excluded from the scope of the claims in the patent application procedures for the patented invention [No Special Circumstances].

(ii) [E]ven if said part is replaced with a part in the subject product, the purpose of the patented invention can be achieved, and the same function and effect can be obtained

…”Whether or not the purpose of the patented invention can be achieved, and the same function and effect can be obtained” by the subject product is determined depending on whether the subject product can solve the problem that could not be solved by conventional art but could be solved by the patented invention, comparing art publicly known before filing the application for the patented invention with the patented invention.

In other words, the “purpose” and “function and effect” of the patented invention mentioned above are to be determined by comparing art publicly known at the time of the filing the application for the patented invention with the patented invention, and basically, they should be determined based on the “problems to be solved by the invention” in the “detailed description of the invention” section, or descriptions in the “effect of the invention” section of the patent specification.

In determining the same, it is not reasonable to judge the existence of the second requirement of the doctrine of equivalents by considering any function and effect which can be recognized in addition to the function and effect for solving the problem, or function and effect specific to embodiments in the specification as the “purpose” or “function and effect” of the patented invention referred to in the second requirement. If the subject product is required to achieve such additional function and effect in addition to the function and effect for solving the problem, or function and effect specific to embodiments, there exists almost no room for acknowledging patent infringement under the doctrine of equivalents….

…  (The plaintiff’s product) merely produces an additional effect in addition to producing the effect of the patented invention and does not form the basis of denying the fulfilment of the second requirement of the doctrine of equivalents. (The Court acknowledged the existence of the second requirement of the doctrine of equivalents.)