Japan / Patents / Doctrine of Equivalents

In the Journal of the Japanese branch of AIPPI for March, 2000, (Volume 25, No 2), an article by David Bannerman and Chris Hamer compares the different approaches to the "Doctrine of Equivalents" in Japan, the United Kingdom, the United States and Germany. The doctrine determines in effect the narrowness with which a claim of infringement of a patent may be determined by the Courts. In Germany, for example, "the protection given by the patent extends to cover all equivalents to the claimed feature which a skilled person would regard as alternative solutions to the problem posed by the invention if it would have been obvious to such a skilled person that the use of an equivalent element would give the same result as that achieved by the feature defined in the claim". The authors discuss the ruling by the Japanese Supreme Court in February 1998 (following the decision of the Osaka High Court in the tissue plasminogen activator case), which sets out the five requirements for the doctrine of equivalents to apply, and compare the tests to those applied in the United Kingdom. The authors put the ruling in the context of a number of cases from the British, German and US courts and conclude that "there seems to be an international tendency towards convergence of the law on the doctrine of equivalents, at least as regards Europe and Japan".[20013]