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
Priority claimed from JP56140971Aexternal-prioritypatent/JPS5843689A/en
Priority claimed from JP57053822Aexternal-prioritypatent/JPS58172096A/en
Application filed by Hitachi LtdfiledCriticalHitachi Ltd
Priority claimed from EP19820304682external-prioritypatent/EP0076047B1/en
Application grantedgrantedCritical
Publication of ATE21475T1publicationCriticalpatent/ATE21475T1/en