| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem, wherein in the conventional optical sensor circuits for motor vehicles which directly amplifies current from a photodiode, its amplifier is saturated depending on the brightness of sunlight, and as a result, the detection of artificial light becomes delayed, and lighting headlights is delayed when entering a tunnel. SOLUTION: An optical sensor circuit 1 for motor vehicles, which amplifies an output from a light-receiving element 2a by using an amplifying circuit and obtains an output for decision, used for deciding the properties of the light received, is equipped with an AC-amplifying circuit 4, a DC-amplifying circuit 5 and an operation circuit 6. The output for decision is obtained through the operation circuit, by adding a signal output amplified by the AC amplifying circuit, to a signal output amplified by the DC amplifying circuit. COPYRIGHT: (C)2005,JPO&NCIPI
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