To accurately control the color of emitted light regardless of changes in ambient temperatures by compensating detected output variations by temperature characteristics of a light quantity sensor, and to reduce the cost of a lighting system by dispensing with a temperature sensor.
This lighting system 1 is equipped with a light quantity sensor part 5, a memory part 6, a temperature estimating part 71, and a correction part 72, The memory part 6 memorizes a first table for estimating the ambient temperatures, and a second table showing a relation between the ambient temperatures and correction values almost equal to the detected output variations by the temperature characteristics of the light quantity sensor part 5. Since the temperature estimating part 71 estimates the ambient temperature on reference to the first table, no temperature sensor is required, and the cost reduction can be attained. In addition, since the correction part 72 refers to the second table, and corrects the detected output by using the correction value corresponding to the estimated ambient temperature, the detected output variations by the temperature characteristics of the light quantity sensor 5 can be compensated. Accordingly, color temperatures of emitted light can be highly accurately controlled regardless of changes in the ambient temperatures.
KOBAYASHI MASAKI
Katsumi Taguchi
Shinichi Mizuta