Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi LtdfiledCriticalHitachi Ltd
Priority to JP1488976ApriorityCriticalpatent/JPS5298586A/en
Publication of JPS5298586ApublicationCriticalpatent/JPS5298586A/en