Electric Storage Battery v. Shimadzu

Electric Storage Battery v. Shimadzu

Electric Storage Battery v. Shimadzu

In the Electric Storage Battery v. Shimadzu case from 1934, the plaintiff Shimadzu was granted patent protection after the Circuit Court had taken protection away. The decision to remand back to the District Court’s decision was made because prior public use could not be proven by the defense. The plaintiff was granted protection based on the patent obtained before commercial use of his product began by the defendant.

Case Description

The plaintiff had developed a battery that featured never before used chemicals and other substances. The battery was built to last longer and was more powerful than others on the market. The plaintiff had developed the battery in his country of residence, Japan. The plaintiff did not patent his product in Japan nor expose it to anyone in the United States.

A former employee, the defendant, had worked in the factory that made the new batteries. He began manufacturing his own batteries that used some of the same new chemicals as the plaintiffs. The plaintiff successfully filed for his patent in the United States but the defendant claimed his battery was already being used by the public prior to the plaintiff obtaining a patent.


The original ruling by the District Court was upheld and the plaintiff's patent was ruled valid. The public use claim by the defendant had two problems: the public use had to occur for a full two years before the plaintiff’s patent was granted. Also, the defendant’s battery was ruled to be in its experimental stage. An item in its experimental stage does not qualify as being a part of public use. The plaintiff was ruled the original patent holder of the battery and his patent claim was deemed valid. The defendant was guilty of patent infringement due to the failure of his public use defense.




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