Legal status (The legal status 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 status listed.)
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 JP730983ApriorityCriticalpatent/JPS59133440A/ja
Publication of JPS59133440ApublicationCriticalpatent/JPS59133440A/ja
Publication of JPH0371647B2publicationCriticalpatent/JPH0371647B2/ja
G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
G01J1/00—Photometry, e.g. photographic exposure meter
G01J1/10—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void
G01J1/16—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void using electric radiation detectors
G01J1/1626—Arrangements with two photodetectors, the signals of which are compared