Is beforehand configurated there is a intruder and it is large, are distinguished

摘要

PROBLEM TO BE SOLVED: To obtain an image with which a night trespasser can be discriminated by controlling a light source so that the light source is light when its periphery, is light dark in the night, and intermediately light in the evening. ;SOLUTION: In daytime, since the CdS detection voltage of 1st and 2nd comparators 3 and 4 are higher than comparison voltages for the evening and night, the collectors of transistors(TR) 6 and 7 for LED light intensity adjustment at H level, and the base of a Tr₅ for LED driving is held at H and a maximum current flows, so that an LED1 emits light with maximum illuminance. In the evening, when the ambient illuminance reaches an evening comparison voltage, the comparator 3 operates to turn on the Tr₆ and turns off the Tr₅, thereby supplying an intermediate current to the LED1. In the night, when the ambient illuminance reaches a night comparison voltage, the comparator 4 operates to turn on the Tr₆ and turn off the Tr₅. At the same time, the comparator 3 turns off via a diode D₃ and a resistance R₂ in order and the minimum collector current of the Tr₇ flows to the LED1.;COPYRIGHT: (C)1997,JPO