Electric Storage Battery Co. v. Shimadzu

Background

The dispute involves a Japanese inventor who conceived and reduced to practice certain methods and an apparatus for making finely divided lead powder in August 1919, and a U.S. manufacturer that began using a similar machine and process in early 1921 and reached commercial production by June 1921. The Japanese inventor filed three U.S. patent applications in 1922, 1923, and 1926. The U.S. company challenged the patents, and the lower courts found in favor of the Japanese inventor on the date of invention and infringement.

Reasoning

The Court addressed three questions: whether a foreign inventor may prove an earlier date of invention; whether delay or concealment by the patentee barred relief; and whether commercial use in the United States more than two years before filing prevents a patent. The Court held that the statutes do not limit the inventor’s proof by place of invention, so a foreign inventor may show an earlier actual invention date. The Court also explained that abandonment must be pleaded and proved and found the defense was not properly presented. But the Court found that commercial production in the United States beginning in June 1921 constituted a statutory “public use” and therefore barred two of the patents (the 1923 and 1926 applications).

Real world impact

As applied here, two patents were invalidated because U.S. commercial use began more than two years before the U.S. applications, while the earliest patent (filed January 1922) was not barred and was returned to the trial court for further determination of validity and infringement. The decision lets foreign inventors prove early invention dates, but it upholds the two-year public-use bar against later-filed patents.